Synergistic Effect Research Articles

Abstract 2211: A novel combined immunotherapy of gut microbial metabolite butyrate and oncolytic adenovirus in colorectal cancer

Abstract Butyrate, a short-chain fatty acid (SCFA) produced by gut bacteria in the colon, serves as a critical energy source for colonocytes. Gut microbiota and its primary metabolite, butyrate, have been reported to potentially modulate tumor sensitivity to chemotherapy or immunotherapy, although the underlying mechanisms remain unclear. Oncolytic virotherapy is a promising antitumor treatment that selectively induces oncolytic cell death in tumor cells. Previously, we developed OBP-702, a telomerase-specific oncolytic adenovirus armed with the p53 tumor suppressor gene, which demonstrated potent antitumor effects across various cancer types. Oncolytic virotherapy is also known to stimulate antitumor immunity. In this study, we investigated the combined effects of OBP-702 and butyrate on colorectal cancer and elucidated the underlying mechanisms. In vitro, the combination of OBP-702 and butyrate exhibited synergistic cytotoxicity against various human and murine colorectal cancer cell lines. In vivo, the combination therapy significantly suppressed tumor growth in HCT116 and CT26 subcutaneous tumor models compared to monotherapy with either OBP-702 or butyrate alone. These synergistic effects were mediated by butyrate enhancing OBP-702's efficacy through the upregulation of coxsackievirus and adenovirus receptor (CAR) and integrin expression on tumor cells, improving viral infection efficiency. Butyrate also increased MHC-I expression on tumor cells through activation of the cGAS-STING pathway, leading to enhanced CXCL10 expression. This, in turn, activated antitumor immunity by recruiting CD8-positive T cells to the tumor microenvironment. The synergistic effects of butyrate and OBP-702 were further confirmed in an orthotopic colorectal tumor model with liver metastases using luciferase-expressing CT26 cells. In this model, the combination therapy not only reduced tumor growth but also improved survival by enhancing antitumor immunity mediated by CD8-positive T cells. To translate these findings into a more clinically relevant approach, butyrate-producing bacteria, Clostridium butyricum Miyairi 588 (CBM588), were used in place of butyrate. The combination therapy of CBM588 and OBP-702 demonstrated similar synergistic antitumor effects in mouse subcutaneous and rectal tumor models. In conclusion, the combination of OBP-702 and butyrate shows promise as a synergistic antitumor strategy and may represent a novel therapeutic approach for colorectal cancer. Citation Format: Tetsuya Katayama, Shinji Kuroda, Masaki Sakamoto Sakamoto, Eri Takeda, Yu Mikane, Shunya Hanzawa, Daisuke Kadowaki, Yusuke Yoshida Yoshida, Masashi Hashimoto, Nobuhiko Kanaya, Yoshihiko Kakiuchi, Satoru Kikuchi, Shunsuke Kagawa, Hiroshi Tazawa, Yasuo Urata, Toshiyoshi Fujiwara. A novel combined immunotherapy of gut microbial metabolite butyrate and oncolytic adenovirus in colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2211.

CDK4/6 Inhibitor Can Improve Niraparib Sensitivity and Reverse Acquired Drug Resistance Through Endonuclease G Nuclear Translocation in BRCA Wild-Type Ovarian Cancer: A Vitro Study.

To investigate whether the CDK4/6 inhibitor TQB-3616 has synergistic effects with niraparib ZL-2306 in suppressing BRCA wild-type ovarian cancer and to explore the mechanisms of combined therapy. In vitro study. Laboratory of a tertiary hospital and Experimental Animal Centre of Shanghai Jiaotong University School of Medicine. SKOV3 (human ovarian cancer cell line). The BRCA wild-type ovarian cancer cell line, SKOV3, was used, and the niraparib-resistant cell line (SKOV3-NR) was generated using a concentration-increasing method. The effects of combined therapy with TQB-3616 and ZL-2306 on cell viability, long-term survival, apoptosis and cell cycle were studied invitro and invivo, and DNA damage was detected. Proteomic mass spectrometry was performed to determine the mechanism of action underlying combined therapy. CDK4/6 and niraparib efficacy. A niraparib-resistant strain of the wild-type BRCA ovarian cancer cell line SKOV3 was generated, and the CDK4/6 inhibitor TQB-3616 was combined with niraparib ZL-2306 to inhibit the growth of ovarian cancer cells and reverse drug resistance. The feasibility and effectiveness of ZL-2306 in combination with TQB-3616 were demonstrated in a tumour-bearing nude mouse model. Combined therapy with the CDK4/6 inhibitor TQB-3616 and niraparib ZL-2306 showed synergistic antitumour effects against BRCA wild-type ovarian cancer without increasing the toxicity of each drug. The antitumour effect may be related to mitochondrial apoptosis, where EndoG nuclear translocation plays a critical role. This study proposes combined therapy of CDK4/6 and PARP inhibitors as a novel approach for the treatment of refractory ovarian cancer.

Abstract 3528: Combination therapy with HIF1α/c-MET peptide vaccine and bone-modifying agents is a promising strategy for suppressing bone metastases though a synergistic effect in mouse model of metastatic triple-negative breast cancer

Abstract Metastatic triple-negative breast cancer (mTNBC) remains incurable due to its aggressiveness and high metastatic potential, particularly to bones. Bone metastases activate osteoclasts, resulting in severe pain and bone destruction. While bone-modifying agents such as denosumab (anti-RANKL) and bisphosphonate (zoledronic acid; ZA) have been commonly used to inhibit the activity of osteoclasts, they have limitations such as high cost and jaw osteonecrosis. Due to the high immunogenicity and hypoxic tumor microenvironment (TME) of TNBC, immunotherapies such as immune checkpoint inhibitors (ICIs) and cancer vaccines are widely explored as treatment options. In our previous study, we demonstrated that HIF1α/c-MET peptide vaccine combined with anti-PD-1 effectively inhibited bone metastases. However, in clinical practice, many patients exhibit low response rates due to the heterogeneity of TNBC and its diverse immune evasion mechanism, highlighting the need for new strategies to reverse the TME. The synergistic effects of bone-modifying agents, such as denosumab or ZA have not yet been explored. This study aimed to evaluate whether the combination therapy of HIF1α/c-MET peptide vaccine with bone-modifying agents will provide a synergistic effect for suppressing bone metastases. We established the bone metastatic model by intracardiac inoculation of M6-bone cells in C3(1)Tag mouse. Mice were vaccinated with HIF1α/c-MET peptide vaccine weekly for three times and treated anti-PD-1 or anti-RNAKL or ZA. Control group received PBS vaccination and treated with IgG. Weekly In vivo imaging showed that combination therapy with HIF1α/c-MET peptide vaccine and bone-modifying agents reduced metastases. Through micro-CT and bone volume-to-total volume analysis, bone metastasis and destruction were reduced in the combination therapy of peptide vaccine with bone-modifying agents compared to the anti-PD-1 combination group. To understand the TME changes more comprehensively, immunofluorescence staining of HIF1α and c-MET is ongoing to confirm the inhibitory effects of the peptide vaccine on targeted oncogenic protein. Osteoclast activity is also being quantitatively assessed by analyzing the ratio of osteoclast surface to bone surface using tartrate-resistant acid phosphatase (TRAP) staining. To determine whether combination therapy can modulate the TME, tumor infiltrating lymphocytes (TILs) are being evaluated by assessing the expression of CD4 and CD8. Although further analysis of TME is necessary, we propose that the combination therapy of HIF1α/c-MET peptide vaccine with bone-modifying agents may provide a promising strategy for suppressing bone metastases in mTNBC. Citation Format: JinHwa Hong, Soon Young Lim, Hye Yeon Rho, Dong Ge Ra Mi Moon, Ju Won Kim, Jiwon Lee, Kyong Hwa Park. Combination therapy with HIF1α/c-MET peptide vaccine and bone-modifying agents is a promising strategy for suppressing bone metastases though a synergistic effect in mouse model of metastatic triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 3528.

Abstract 602: Synergistic anti-tumor effects of andrographis and lactoferrin in colorectal cancer via modulation of AXIN2/Wnt/E-cadherin signaling pathway

Abstract Background: Colorectal cancer (CRC) is one of the most common malignancies worldwide and 20-25% of patients experience metastatic colorectal cancer (mCRC) at initial diagnosis. However, the high mortality rates associated with mCRC are largely due to the inadequate efficacy of current treatments and the development of acquired resistance to conventional chemotherapy. Recent studies have indicated that Lactoferrin is frequently used as a drug transport carrier, enhancing drug absorption. Natural compounds like Andrographis offer cost-effective, multi-targeted treatments for tumors. Therefore, we hypothesize that Lactoferrin might serve as a transport carrier for Andrographis, improving its bioabsorption and in offering a more pronounced anticancer activity in CRC. Methods: We conducted a series of in-vitro and in-vivo experiments to evaluate the synergistic anticancer effects of Lactoferrin and Andrographis in CRC. Furthermore, we performed a genomewide transcriptomic analysis to identified specific growth-signaling pathways targeted by the combined treatment and subsequently validated these findings in cell lines and patient-derived 3D organoids. Results: The combined treatment with Lactoferrin and Andrographis exhibited excellent synergistic anti-tumor potential, affecting cell viability, proliferation, migration, and invasion in CRC cells. In CRC, metastasis commonly occurs through the epithelial-mesenchymal transition. This combination treatment exerted the most pronounced effects on β-catenin responsive transcription and E-cadherin promoter activity. Mechanistically, transcriptomic analysis revealed that the combined treatment resulted in the inhibition of AXIN2 which resulted in E-cadherin-mediated inhibition of Wnt signaling ([FC]: 3.46, P < 0.005). Additionally, we observed that the expression levels of AXIN2 were significantly higher in cancer vs. normal tissues (P < 0.005) in the TCGA dataset. Finally, in 3D organoid models, the combined treatment exhibited superior anti-cancer activity, significantly reducing both the number and size of organoids (P < 0.05). These findings highlight the therapeutic potential of targeting the AXIN2/Wnt/E-cadherin axis with Lactoferrin and Andrographis in CRC. Conclusion: We present evidence that the synergistic anticancer effects of Lactoferrin and Andrographis in CRC are mediated through the AXIN2/Wnt/E-cadherin axis, highlighting their potential as a therapeutic strategy. Citation Format: Yuan Li, Caiming Xu, Takayuki Noma, Ajay Goel. Synergistic anti-tumor effects of andrographis and lactoferrin in colorectal cancer via modulation of AXIN2/Wnt/E-cadherin signaling pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 602.

Abstract 4313: COPS5 inhibition synergizes the antitumor effect of trastuzumab by PTEN upregulation in HER2 amplified gastric cancer

Abstract COP9 Signalosome Subunit 5 (COPS5), a deubiquitinating enzyme, contributes to chemoresistance, and its expression is closely correlated with poor prognosis in patients with solid tumors. However, the role of COPS5 amplification in patients with gastric cancer (GC) and its inhibition in HER2-amplified GC models has never been elucidated. In the curated stomach adenocarcinoma cohort (n=294) from The Cancer Genome Atlas datasets, COPS5 amplification significantly co-occurred with HER2 amplification (10.5% vs. 2.7%, P=0.040) and was associated with worse disease-free survival (median 12.6 vs. 45.2 months, P=0.012) and overall survival (median 21.4 months vs. not reached, P=0.004) after surgery. In HER2-amplified GC cell lines, NCI-N87, SNU216, and OE19, COPS5 inhibition using CSN5i-3, a selective COPS5 inhibitor, synergistically enhanced the antiproliferative effect of trastuzumab. After CSN5i-3 treatment, COPS5 knock-out (KO) cell lines demonstrated a uniform increase in PTEN transcription and translation levels. This effect was mediated by SNAIL ubiquitination, suppressing the AKT downstream signaling pathway. However, in PTEN KO cell lines, the synergistic effect of CSN5i-3 and trastuzumab was not apparent. Similarly, reduced PTEN expression caused by SNAIL overexpression also decreased the responsiveness of CSN5i-3 treatment. Moreover, COPS5 KO cells exhibited increased sensitivity to the proliferative effect and downstream signaling inhibition of AKT inhibitors MK2206 and capivasertib compared to control cells. In a mouse xenograft model of NCI-N87 cells, CSN5i-3 treatment combined with trastuzumab yielded a synergistic anti-tumor effect compared to monotherapy without notable changes in body weight. This effect was accompanied by enhanced apoptosis and reduced SNAIL and AKT downstream signaling activity. In conclusion, the synergistic antiproliferative effect of COPS5 inhibition and trastuzumab was attributed to increased PTEN expression via SNAIL ubiquitination, resulting in the AKT downstream inhibition. These findings highlight the potential of COPS5 as a therapeutic target in combination with trastuzumab for HER2-amplified GC, warranting further clinical studies. Citation Format: Sung-Hyun Hwang, Ji-Won Kim, Kuijin Kim, Haseseong Park, Andrew Aguirre, Keun-Wook Lee. COPS5 inhibition synergizes the antitumor effect of trastuzumab by PTEN upregulation in HER2 amplified gastric cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 4313.

Abstract 2753: Potential novel interventions of oncohistones, epigenetic modifications, and RNA processing machinery in betel-nuts related HNSCC in Taiwan

Abstract Background: Betel nut chewing leads to strong invasion & recurrence. We found betel-nuts exposed HNSCC cell line, TW2.6, caused treatment refractoriness in Taiwan with high PDL1, defective p53 mutation, p16 loss, & BCL2 overexpression. PI3K/AKT/mTOR interventions, ALK/IGF1R inhibitor, CDK4/6 inhibitor, BCl2 inhibitor, WEE1 inhibitor, ATR inhibitor, DNA-PK inhibitor, AT2AR inhibitor, Mcl-1 inhibitor, MEK1/2 inhibitor, JAK2 inhibitor, CXCR4 inhibitor, FAK inhibitor, p53 reactivator, MDM2 inhibitor, SHP2 inhibitor, PARP7 inhibitor, IAP inhibitor, GLS1 inhibitor, eribulin, & VEGFR2/ PDGFR/FGFR or VEGFR2/c-MET/Axl triple blockage might be effective on TW2.6 and reverse treatment refractoriness, through the inhibition of mesenchymal transformation, pRB, & PI3K/AKT /mTOR signaling and modulation of stemness & PD1/PDL1 pathway. Besides, PLK inhibitor & GLS1 inhibitor seemed good radiosensitizers for TW2.6(AACR2024). The genomic signature of TW2.6 was figured out(AACR2020) with PIK3CA H1047R mutation, high TMB/MSS, VEGF-A amplification, p53/MYC/HRAS/DDR2/ PDGFRbeta/EPHB1/ATM mutations, FAT1 loss, amplification of TERT/ FGF10/CCND3/SOX9/IL-7R/SDHA/ RICTOR/FLCN, CDK12/PTPRD loss of function, deletions of STK11/ARID1B/MITF/ TNFAIP3, & SETD2(a histone lysine methyltransferase)/KDM5A(a lysine demethylase)/CDK8 mutations. H3K36 mutation and NSD1 defects altering H3K36 methylation will block cellular differentiation and promote oncogenesis. Disrupting NSD1 in HNSCC cell lines led to CpG hypomethylation & enhanced cisplatin sensitivity. Methods: TW2.6 used to test (1)in vitro drug sensitivity to (a)Chemical Modulators of Splicing; (b)PRMT5 inhibitor; (c)CDK9 inhibitor, EZH2i, DNMT3i, BRD/BET4i, and HDACi; (d)NSD1/SETD2 inhibitor; (e)METTL3 inhibitor; (2)synergistic effects with other therapies by MTT assay, colony formation, flow cytometry, & western blotting. Results: Epigenetic modifications were tested over TW2.6. AZD4573(CDK9 inhibitor), tazemetostat(EZH2 inhibitor), azacitidine(DNMT3 inhibitor), AZD5153(BRD4/BET inhibitor), and romidepsin(HDAC inhibitor) were effective over TW2.6 and enhanced ICIs efficacy. AZD4573 can synergize with tazemetostat, AZD5153, AZD6094(c-MET inhibitor), AZD5991(Mcl-1 inhibitor), & AZD2014(TOC1/2 inhibitor); but no synergistic effects with DDR interventions, such as AZD6738(ATR inhibitor) & olaparib except AZD1775(WEE1 inhibitor). AZD4573 will cause the drop of EMT signals, pRB, & p70S6K1 and prominent elevation of p-PARP. TW2.6 was also effective towards STM2457(METTL3 inhibitor) and JNJ64619178(PRMT5 inhibitor). Conclusions: TW2.6 was sensitive to epigenetic modifications due to CDK8/SETD2/KDM5A mutations & ARID1B loss. Novel RNA processing interventions and epigenetic modifications for radiosensitization & immuno-modulation may be future trends. Citation Format: Jo-Pai Chen, Jui-Ying Chang, Ruey-Long Hong. Potential novel interventions of oncohistones, epigenetic modifications, and RNA processing machinery in betel-nuts related HNSCC in Taiwan [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2753.

Abstract 6249: Probabilistic causal network models from real-world prostate cancer data identify potential synergistic combinations with CBP/P300 inhibitors

Abstract The current standard of care for metastatic castration resistant prostate cancer (mCRPC) includes androgen-receptor signaling inhibitors (ARSIs), chemotherapy, PARP inhibitors (PARPi), or PSMA-radioligand therapies. Although these novel therapies have yielded substantial benefits for patients, many fail to respond or quickly develop resistance. Previous work identified key regulatory programs driving AR-altered, ARSI-resistant, late-stage prostate cancer, and further identified and validated that treatment with the CBP/p300 inhibitor pocenbrodib inhibits cancer cell growth both in vitro and in vivo. Here, we focus on identifying targeted therapies where combination with pocenbrodib could improve clinical response in late-stage prostate cancer. Previous analyses identified that treatment of prostate cancer cell lines with pocenbrodib downregulates a group of genes, termed a subnetwork, capturing G2M, E2F, and DNA repair mechanisms, suggesting that combination with a therapy that induces DNA damage or inhibits DNA repair could be additive or synergistic. Cell cycle profiling following treatment of cell lines with pocenbrodib confirmed induction of G2M cell cycle arrest. Next, we systematically ranked current targeted therapies based on publicly available RNA-seq signatures and signatures derived from RWD (e.g. BRCA2 alterations) to identify therapies that target our subnetwork of genes enriched for G2M, E2F, and DNA repair mechanisms. Given that both PSMA-radioligand therapies and PARP inhibitors induce DNA damage or inhibit DNA repair, we hypothesize that these drugs in combination with pocenbrodib would lead to additive or synergistic effects by enhancing the PARPi and PSMA-radioligand efficacy via their known mechanisms of action. To validate these hypotheses, we treated a panel of 5 genetically-diverse prostate cancer PDX-derived organoids with pocenbrodib, the PARPi olaparib, and in combination. The combination of pocenbrodib with olaparib led to additive or synergistic effects in 3 out of the 5 organoids, consistent with those showing some level of response to olaparib as a single agent. To evaluate the potential for combination benefit with PSMA-radioligand therapy, an in vivo efficacy study was performed using the PSMA+ 22Rv1 prostate cancer xenograft model. Addition of a low dose of pocenbrodib to a single dose of Lu177-PSMA617 (60 MBq) led to better tumor growth inhibition control than either single agent on its own. Mechanistic analyses from RNAseq are ongoing. Together, our integrated omics and experimental analyses support the hypothesis that combination of pocenbrodib with DNA damage-inducing or -inhibiting targeted therapies may provide further therapeutic benefit to prostate cancer patients than single agent therapies alone. Citation Format: Veronica Calvo, Bonnie Dougherty, Ananya Dutta, Duo Xu, Qi Pan, Andrew Armstrong, Jens Renstrup, Jason Somarelli, Eric Schadt. Probabilistic causal network models from real-world prostate cancer data identify potential synergistic combinations with CBP/P300 inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 6249.

Abstract 2173: Targeting USP7 with MEK1/2 inhibition synergizes to induce pyroptosis and enhance immunotherapy in NRAS mutant melanoma

Introduction: There is an urgent need for targeted therapies in metastatic melanoma patients with NRAS mutations, who comprise more than 25% of this population. This study investigates the therapeutic potential of targeting Ubiquitin-Specific Peptidase 7 (USP7) with a highly selective inhibitor, FT671, in NRAS mutant melanoma. In addition, the synergistic effects of the combination of FT671 with MEK1/2 inhibitor (MEKi) on pyroptosis induction, tumor suppression and immune activation were evaluated. Moreover, the potency of triple combination of FT671, MEKi and anti-PD-1 antibody was assessed. Experimental Procedures: We employed a combination of genetic knockout models and pharmacological inhibition to validate the selectivity of FT671 in vitro. Cell proliferation assays were used to determine IC50s and the synergistic effects. Flow cytometry assays were performed to monitor cell cycle arrest and cell death and analyze intratumoral immune cells. Western blot assays were used to examine if the combinations markedly induced the cleavage of GSDME. A CRISPR based screen was performed to explore the mechanism of action of FT671. We also utilize isograft melanoma models in immunocompetent mice to assess tumor growth, immune cell infiltration, and therapeutic outcomes. Results: As a validated USP7 selective inhibitor (USP7i), FT671 treatment effectively induced cell cycle arrest, reduced cell proliferation in vitro, and delayed tumor growth in NRAS mutant melanoma models in vivo. Knockout of TP53BP1, TP53 or CDKN1A conferred resistance to FT671, indicating activation of a functional p53 pathway is a major mechanism of action for the efficacy of USP7i in melanoma. The combination of FT671 with MEKi resulted in synergistic effects, and induced pyroptosis in vitro. In vivo, the combined treatment significantly suppressed tumor growth, prolonged survival, and enhanced anti-tumor immunity, evidenced by increased infiltration of CD8+ T cells and mature dendritic cells in tumors. Notably, the triple therapy with FT671, MEKi, and anti-PD-1 antibody led to tumor regression and durable responses in an isograft melanoma model. Conclusions: These findings highlight the potential of USP7 inhibition, combined with MEKi, as a promising strategy for treating NRAS mutant melanoma, an 'undruggable' target. Moreover, this combinatorial approach is able to enhance the efficacy of anti-PD-1 antibody, providing a compelling rationale for its clinical application as an adjuvant for immune checkpoint inhibitors. Citation Format: Liya Su,Dinghao Wang,Timothy J. Purwin,Sophia Ran,Qi Yang,Qingrun Zhang,Weijia Cai. Targeting USP7 with MEK1/2 inhibition synergizes to induce pyroptosis and enhance immunotherapy in NRAS mutant melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2173.

Abstract 1770: HM100760, a potent and selective MAT2A inhibitor, demonstrates a synergistic anticancer effect when combined with a PRMT5 inhibitor in MTAP-deleted cancer

Abstract Methionine adenosyltransferase 2A (MAT2A) is the primary enzyme responsible for the synthesis of S-adenosylmethionine (SAM) from methionine and ATP. SAM serves as a universal methyl donor in various transmethylation and biosynthetic pathways. Recently, MAT2A has emerged as a synthetic lethal target in cancers harboring deletions of the methylthioadenosine phosphorylase (MTAP) gene, which occurs in approximately 15% of all cancers. MTAP deletion results in the accumulation of methylthioadenosine (MTA), which partially inhibits protein arginine methyltransferase 5 (PRMT5). Inhibition of MAT2A in MTAP-deficient cancers leads to reduced intracellular SAM levels, which sensitizes PRMT5 to further inhibition. Likewise, this interplay offers a strong rationale for the combinational use of MAT2A inhibitors, which block SAM synthesis, with MTA-cooperative PRMT5 inhibitors. Here, the biochemical activity of HM100760, a potent and selective MAT2A inhibitor, was evaluated in terms of its effect on MAT2A enzymatic function, cellular SAM levels, and symmetric dimethylarginine (SDMA) regulation. HM100760 exhibited strong inhibition of MAT2A catalytic activity, leading to significant reductions in SAM and SDMA levels in HCT116 MTAP-null cells. In addition, HM100760 displayed robust anti-proliferative effects across a range of MTAP-deficient cancer cell lines, including those derived from pancreatic, bladder, and non-small cell lung cancer (NSCLC). In preclinical in vivo studies, HM100760 demonstrated dose-dependent tumor growth inhibition in multiple MTAP-null xenograft models, including HCT116, KP-4, and LU99. Moreover, combining HM100760 with a PRMT5 inhibitor in the endogenous MTAP-null LU99 xenograft model resulted in a synergistic antitumor effect, outperforming monotherapy treatments. Notably, HM100760 achieved this therapeutic efficacy without causing significant body weight loss or observable clinical symptoms, underscoring its favorable safety profile. In conclusion, HM100760 is considered a promising therapeutic candidate for MTAP-deleted cancers. It exhibits potent antitumor activity as a monotherapy and demonstrates enhanced efficacy when combined with a PRMT5 inhibitor. Ongoing preclinical studies aim to further characterize HM100760’s therapeutic potential and broaden its application in MTAP-deficient cancer treatment. Citation Format: Minjeong Kim, Eun Joo Kwak, Miyoung Lee, Soonki Park, Hobin Lim, Soyeon Kim, Hye Sun Han, Seung Hyun Jung, Jooyun Byun, Sang Hyun Lee, Young Gil Ahn. HM100760, a potent and selective MAT2A inhibitor, demonstrates a synergistic anticancer effect when combined with a PRMT5 inhibitor in MTAP-deleted cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 1770.

Abstract 3036: Direct co-targeting of Bcl-xL and Mcl-1 exhibits synergistic anti-cancer effects in AR-V7-expressing mCRPC preclinical models

Abstract There is an unmet need to develop novel treatment options for patients with metastatic castration-resistant prostate cancer (mCRPC). Patients often develop resistance to hormonal therapies that target the AR-axis (e.g., abiraterone, enzalutamide). A splice variant of AR, AR-V7, is associated with resistance to these inhibitors as well as mCRPC progression and poor prognoses. We embarked upon a high-throughput screen to identify synergistic combinations of targeted therapies using two CRPC cell lines, LNCaP95 and VCaP-CR. The goal of the drug screen is to identify rational targeted combination therapies for mCRPC, where efficacy can be achieved at lower, equally effective doses in order to minimize toxicity. Extensive bioinformatic analysis identified several synergistic combinations, including dual targeting of Bcl-2 family proteins using BH3 mimetics. Combinations targeting Bcl-xL (A-1331852 and Navitoclax) and Mcl-1 (S63845) synergistically decreased cell viability and induced apoptotic activity via cleavage of PARP, caspase 3, and caspase 7 across AR-V7 expressing CRPC cell lines (LNCaP95, VCaP-CR, 22Rv1) as early as two hours post-treatment. The effect of the treatment combination on downstream targets was assessed via western blot analysis. We demonstrated synergistic anti-tumor effects with Mcl-1/Bcl-xL co-targeting in three-dimensional (3D) spheroid CRPC models and in the patient-derived LuCaP-167CR organoid model, which represents a more physiologically relevant model for evaluating drug response and efficacy. We also explored the use of a Bcl-xL-specific PROTAC to minimize platelet toxicity associated with Bcl-xL inhibitors in the clinic. We showed similar synergistic efficacy with the S63845/Bcl-xL targeting PROTAC combination in the 3D spheroid models compared to the small-molecule Bcl-xL inhibitors while also inducing apoptosis. Our findings provide unique insight into the dependence on Bcl-2 family proteins in mCRPC. Our findings also support further preclinical development of Bcl-xL and Mcl-1 inhibitors for mCRPC. Citation Format: Benjamin C. Brim Andres F. Leon Erica L. Beatson Jessica D. Kindrick Kinjal Bhadresha Xiaohu Zhang Giulia C. Napoli Emily N. Risdon Keith T. Schmidt Erin Beck Carleen Klumpp-Thomas Michele Cerebelli Douglas K. Price Cindy H. Chau Craig J. Thomas William D. Figg. Direct co-targeting of Bcl-xL and Mcl-1 exhibits synergistic anti-cancer effects in AR-V7-expressing mCRPC preclinical models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 3036.

Abstract 4234: Synergistic anti-proliferative effects of JIN-001, a novel HSP90 selective inhibitor, in combination with platinum-based drugs in ovarian cancer cell lines

Abstract Introduction: Heat shock proteins (HSPs) have been considered as a promising therapeutic target for ovarian cancer (OC), the most lethal gynecologic malignancy. HSPs facilitate tumor cell adaptation to short-term stress, promoting the development of more malignant phenotypes and the acquisition of resistance to therapeutic treatments over time. To date, Clinical trials of HSP90 inhibitors have shown modest benefits in advanced cancer patients, with no sufficient efficacy as monotherapy. Here, We investigated the anti-proliferative effects of JIN-001, a selective HSP90i, combined with platinum-based drugs in OC cell lines. Material and methods: We examined the co-treatment effects of JIN-001 and paclitaxel (PTX) or cisplatin (Cis, platinum-based) on viability in OC cell lines (OV90, TOV21G, and OVCAR3) and drug-resistance sublines (OV90/PTX200, TOV21G/PTX100, and OVCAR3-CisR). Drug-resistant OC sublines were generated by gradually exposing OC cells to increasing concentrations of PTX or Cis. Each drug was tested either for monotherapy or in 1:1 ratio combination. Also, we assessed the synergistic anti-proliferative effects of JIN-001 (0.1 or 0.05 μM) with Cis on OVCAR3 and OVCAR3-CisR. Results: Co-treatment of JIN-001 with PTX or Cis reduced IC50 in drug-resistant OC sublines compared to PTX or Cis alone. The IC50 of JIN-001 at a fixed dose in combination with Cis were lower in the OVACAR3 and OVCAR-CisR, compared to the single treatment. IC50 (μM) are shown below. Conclusion: The combination of JIN-001 with PTX or Cis enhanced anti-proliferative effects and reduced IC50 in OC cell lines and drug-resistant sublines compared to monotherapy. This suggests JIN-001’s potential as a combination therapy with platinum-based drugs in OC patients. Further studies are needed to examine whether the combination therapy of JIN-001 and the conventional drugs decelerates the tumor’s ability to adapt and develop drug resistance. Citation Format: Jue Young Kim, Ha-Yeon Shin, Anna Jo, Ethan Seah, Choonok Kim, Jae-Hoon Kim. Synergistic anti-proliferative effects of JIN-001, a novel HSP90 selective inhibitor, in combination with platinum-based drugs in ovarian cancer cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 4234.

Abstract 5648: Effects of olverembatinib (HQP1351) in combination with BCL-2 inhibitor lisaftoclax (APG-2575) in T-cell acute lymphoblastic leukemia (T ALL)

Background: T-ALL is a high-risk hematologic cancer arising from malignant transformation of T-cell progenitors, affecting approximately 15% of newly diagnosed pediatric and 25% of adult ALL cases. Survival in children, young adults, and patients with relapsed or refractory disease is poor with limited treatment options. Some T-ALL subtypes depend on pre-TCR/Src signaling and antiapoptotic BCL-2 family proteins for growth and survival. Olverembatinib, a novel multikinase inhibitor, targets oncogenic Src-family kinases (Lck, Fyn, and YES1) essential for T-cell differentiation, survival, and activation. Lisaftoclax is a novel BCL-2 inhibitor under investigation in late-stage clinical trials for multiple hematologic malignancies. Here, we examined the antitumor effects of olverembatinib combined with lisaftoclax in human T-ALL cell lines and explored potential mechanisms of action. Methods: Cellular proliferation was measured using CellTiter-Glo® assays and apoptosis by flow cytometry. Western blotting was used to elucidate potential mechanisms of action. In vivo activity was evaluated using a subcutaneous MOLT4 cell-derived xenograft mouse model. Results: Olverembatinib in combination with lisaftoclax exhibited strong synergistic antiproliferative effects in T-ALL cell lines MOLT4 and Jurkat, with combination indices of 0.2 and 0.1, respectively; apoptosis analyses revealed that the combination significantly increased the percentage of apoptotic cells compared to either agent alone (p < 0.0001). Olverembatinib 10 mg/kg or lisaftoclax 100 mg/kg alone resulted in no or limited tumor inhibition in MOLT4 xenograft model, with treatment-to-control (T/C) values of 113% and 89%, respectively. However, when co-administered, the combination enhanced tumor growth inhibition (T/C, 60%), achieving a synergy index of 1.67. Mechanistically, olverembatinib inhibited Lck activity, and when combined with lisaftoclax, synergistically reduced activity of downstream transcription factor NF-kB p65, leading to downregulation of the key antiapoptotic protein BCL-xL, which is typically upregulated in BCL-2 inhibitor-resistant T-ALL. In addition, the combination downregulated phosphorylation of AKT and GSK3b kinases, resulting in significant degradation of antiapoptotic protein MCL-1 and c-myc, an essential pro-survival oncogene in T-ALL. Increased cleavage of PARP and caspase-3 (markers of apoptosis) was also observed. Conclusions: Olverembatinib in combination with lisaftoclax demonstrated synergistic antitumor effects in T-ALL, providing a scientific rationale for further clinical evaluation of this novel combination therapy in patients with T-ALL. Citation Format: Bo Peng, Yan Xiong, Zhiyan Liang, Ping Min, Huidan Yu, Bingxing Wu, Guoqing Zhai, Zhou Yu, Dajun Yang, Yifan Zhai. Effects of olverembatinib (HQP1351) in combination with BCL-2 inhibitor lisaftoclax (APG-2575) in T-cell acute lymphoblastic leukemia (T-ALL) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5648.

Abstract 7217: Synergistic anti-cancer effects of dual IGF-1R and EGFR targeting in uveal melanoma

Abstract Uveal melanoma arises from melanocytes in the eye, with approximately 7, 000 patients reported worldwide every year. IGF-1R plays an important role in uveal melanoma metastatic progression, and promotes tumor cell proliferation and survival. However, in previously reported clinical trials, targeting IGF-1R did not significantly inhibit uveal melanoma metastatic spread or patient survival. This could be due to compensatory activation of other receptor signaling pathways. Therefore, the aim of this study is to find other activated receptors in uveal melanoma cells following IGF-1R inhibition which could be co-targeted in a novel combination treatment for metastatic uveal melanoma. Using several uveal melanoma cell lines (Mel202, Omm2.3, Omm2.5, Omm1, 92.1, MP38 and MM28), we found that treatment with linsitinib, an IGF-1R inhibitor, increased EGFR protein expression and activity. Targeting IGF-1R alone with linsitinib, or EGFR alone with gefitinib, did not significantly inhibit growth of uveal melanoma cells. However, combination treatment with linsitinib (10µM) and gefitinib (5µM) significantly inhibited both cell growth and anchorage-dependent/independent colony formation abilities in uveal melanoma cultures. Moreover, Linsitinib and gefitinib co-treatment dramatically increased cleaved PARP protein, an apoptotic maker. Our research suggests that dual targeting of IGF-1R and EGFR could be a novel treatment strategy to inhibit uveal melanoma metastatic dissemination and growth. Citation Format: Pei-Chi Tsai, Charles G. Eberhart, Su-Chan Lee. Synergistic anti-cancer effects of dual IGF-1R and EGFR targeting in uveal melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 7217.

Abstract 5518: Targeting FAK by Ifebemtinib synergizes with Pan RAS inhibitors in treating RAS mutant cancers

Pan-RAS inhibitors have been developed for the treatment of RAS-mutant cancers. Despite the challenges in achieving clinical benefits, targeting Pan-RAS represents a novel strategy for treating these previously considered untargetable malignancies. Previous studies have demonstrated that targeting FAK enhances the therapeutic efficacy of KRAS G12C inhibition in clinical settings, as hyperactivated FAK signaling is a major mechanism of acquired resistance following KRAS G12C inhibition. In the present study, we observed that Pan-RAS inhibitors can induce acquired hyperactivity of FAK, potentially rendering cancer cells resistant to Pan-RAS inhibition. Co-administration of a clinical-stage FAK inhibitor, Ifebemtinib (also known as Ifebe, IN10018), with RMC6236, a Pan-RAS inhibitor, exhibited synergistic cytotoxic effects in multiple RAS-mutant cancer cell lines. Furthermore, we evaluated the dual regimen in KRAS-mutant and NRAS-mutant animal models, where the combination therapy demonstrated superior tumor growth inhibition compared to monotherapy. Our previous findings indicated that FAK inhibition in conjunction with KRAS G12C/G12D inhibition enhances the anti-cancer effects of PD-1 blockade. Here, we confirmed that the combination of Ifebe and RMC6236 also augments the anti-tumor efficacy of PD-1 antibody therapy, suggesting that this treatment enhancement is independent of the specific RAS mutation type. In summary, our study reveals that the combination of FAK inhibitor Ifebe with Pan-RAS inhibitor exhibits synergistic anti-cancer effects and further improves the outcomes of PD-1 blockade therapy. These preclinical results support the need for further clinical investigation. Citation Format: Baoyuan Zhang, Ran Pang, Jiaming Gao, Jingwen Cheng, Ping Zhang, Natasha Qin, Leo Liu, Zaiqi Wang. Targeting FAK by Ifebemtinib synergizes with Pan RAS inhibitors in treating RAS mutant cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5518.

The use of Local Flora in Treating Diarrheal Diseases in Children

Diarrheal diseases remain a significant cause of morbidity and mortality among children under five, particularly in resource-limited settings. Traditional medicine, utilizing local flora, offers a cost-effective and accessible alternative for managing diarrhea. This paper examines the role of indigenous plants in treating diarrheal diseases, emphasizing their antimicrobial, anti-inflammatory, and antioxidant properties. Case studies from Uganda illustrate the potential of these plants in pediatric care. Despite challenges like limited safety data and integration into modern healthcare systems, the inclusion of local flora presents opportunities for sustainable, community-based solutions. Future directions include rigorous research on bioactive compounds, dosage optimization, and synergistic effects, fostering a bridge between traditional and evidence-based medicine. Keywords: Diarrheal diseases, children’s health, local flora, traditional medicine, ethnobotany, pediatric care.

Abstract 822: Combination of carboplatin and CHK1 inhibition to overcome platinum resistance in high grade serous ovarian cancer

Abstract Platinum based chemotherapy is the most effective treatment for high grade serous ovarian cancer (HGSOC). Resistance in the recurrent setting is a poor prognostic indicator with few treatment options. CHK1 inhibitors have been studied in HGSOC in preclinical and early phase trials alone and in combination with cytotoxic chemotherapy, but have not been studied in combination with platinum to our knowledge. We used the CHK1 inhibitor, prexasertib, as a strategy to overcome platinum resistance by promoting cell cycle progression, limiting repair of platinum induced DNA damage. Sensitivity to carboplatin and prexasertib alone and in combination were measured in a panel of pre-clinical HGSOC cell lines. DNA damage was detected using the Repair Assisted Damage Detection method in untreated and treated cells for 24h with carboplatin and prexasertib alone and in combination. An enzymatic cocktail of UDG, FPG, T4PDG, Endo IV, Endo VIII, and AAG was used to extract DNA damaged lesions. Damaged lesions were labeled for detection with polymerase and a Digoxigenin labeled dUTP. Samples were stained for anti-DIG and anti-pCHK1 S317, imaged on a confocal microscope, and analyzed in Nikon Elements software. Expression of pCHK1 S317 was confirmed via Western Blot. A synergistic effect was observed in all cell lines with the combination of carboplatin and prexasertib. In ES2 cells, carboplatin alone resulted in 15.4% cell death and increased to 72.5% (p<0.001) and 86.8% (p<0.0001) with the addition of prexasertib 5nM and 10nM, respectively. In SKOV3 cells, carboplatin resulted in 38.2% cell death and increased to 80.0% (p=0.0002) and 86.6% (p<0.0001). In OvCar4 cells, carboplatin resulted in 53.2% cell death and increased to 90.6% (p=0.0001) and 92.4% (p<0.0001). In OV90 cells, carboplatin resulted in 25.3% cell death and increased to 56.6% (p<0.0001) and 60.1% (p<0.0001). In OvCar8 cells, carboplatin resulted in 29.3% cell death and increased to 91.9% (p<0.0001) and 95.4% (p<0.0001). DNA damage increased in ES2 cells with prexasertib 10 nM + carboplatin (1.4-fold increase, p=0.03), SKOV3 with prexasertib 5 nM + carboplatin (257.0-fold increase, p=0.002), OvCar4 with prexasertib 10 nM + carboplatin (1.4 fold increase, p=0.03) and OvCar8 with prexasertib 10 nM + carboplatin (2.0-fold increase, p=0.0003). There was no difference in DNA damage in OV90 cells. pCHK1 S317 was increased significantly in all 5 cell lines treated with combination therapy, consistent with known phosphorylation of CHK1 at S317 by ATR in response to DNA damage and inhibition of p-CHK1 auto-phosphorylation by prexasertib leading to inactivation. The CHK1 inhibitor, prexasertib, demonstrated a synergistic effect when used in combination with carboplatin, correlating with an expected increase in DNA damage and p-CHK1 S317. The use of CHK1 inhibitors with platinum may be a new treatment strategy in platinum resistant HGSOC. Citation Format: Mackenzie Cummings, Jaden Williams, Jennifer Pierce, Nathaniel Jones, Kevin Lee. Combination of carboplatin and CHK1 inhibition to overcome platinum resistance in high grade serous ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 822.

Abstract 2988: Patient-survival linked TTLL12 isoform switching event sensitizes EAC cells to standard-of-care chemotherapy agents via chaperone-mediated autophagy

Abstract Esophageal adenocarcinoma (EAC) represents a growing health problem characterized by rising incidence and poor prognosis, despite current multimodal therapy. Although EAC has a high mutational burden, it lacks highly prevalent oncogenic drivers that can be therapeutically targeted, as TP53 mutation accounts for over 80% of mutational events in EAC. Recently, our group characterized isoform switching events, defined as a change of dominant gene isoforms between conditions, associated with EAC progression and identified 75 isoform switching events between Barrett’s low-grade dysplasia (BE.LGD) and Barrett’s high-grade dysplasia (BE.HGD) patient samples. Herein, we further investigated whether isoform-switching events may offer prognostic or therapeutic value in EAC. Isoform switching analysis was performed using RNA-seq data derived from 57 patient samples comparing BE.LGD to BE.HGD combined with EAC (BE.HGD+EAC) alone or in combination with TP53 mutations. Patients were further stratified into tertiles based on isoform expression levels, followed by survival analysis. Forty-two isoforms were significantly (P<0.05) linked with all-cause mortality, comparing BE.LGD with BE.HGD+EAC, whereas 39 isoforms were identified when TP53 mutation status was included. Among those identified to be significantly associated with all-cause mortality comparing BE.LGD with BE.HGD+EAC, isoforms of tubulin tyrosine ligase like 12 (TTLL12), a gene linked with aberrant cell proliferation, oxidative stress and cancer progression in other targets, were among the top isoforms switched. Isoform-specific genetic knockdown was performed via siRNA to target the protein-coding isoform of TTLL12 in two EAC cell lines (OE19 and OE33). Knockdown of the TTLL12 protein-coding isoform significantly inhibited cell viability and migration in both cell lines. In addition, synergistic effects on cell viability were observed for TTLL12 knockdown of EAC cells treated with standard-of-care chemotherapeutic agents (Paclitaxel and Carboplatin), suggesting a role for specific isoform-switching events in therapeutic sensitization. Protein-interaction prediction using STRING and immunoblot analysis further supported that TTLL12 is linked with the regulation of chaperone-mediated autophagy (CMA), as evidenced by the induction of LAMP2A and HSC70 in EAC cells. Because CMA is linked with the regulated degradation of CHK1 and mutant TP53 in other cancers, we are currently assessing the role of CMA in regulation of CHK1 and degradation of TP53 in EAC. Future directions include using FDA-approved agents to target CMA in EAC. In conclusion, isoform switching may provide fresh insight for the identification of prognostic markers and inform new potential therapeutic targets for EAC treatment or prevention. Citation Format: Yun Zhang, Rachel Israel, Bryce Vandenburg, Shari Barnett, Jean-Jack Riethoven, Jennifer Clarke, Michelle P. Lee, David A. Ntsiful, Kiran H. Lagisetty, Jules Lin, Rishindra M. Reddy, Chigozrim Ekeke, Andrew C. Chang, David Odell, Laura A. Kresty. Patient-survival linked TTLL12 isoform switching event sensitizes EAC cells to standard-of-care chemotherapy agents via chaperone-mediated autophagy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2988.

Abstract 3660: Machine learning-based combination prediction for Wee1 inhibitor

Abstract Motivation: Wee1 is the gatekeeper gene that allows proper DNA damage repair (DDR) during the G2/M cell cycle transition. Inhibiting the Wee1 gene will abrogate the DDR mechanism and lead cancer cells with high replication stress to premature catastrophic mitosis and eventually apoptosis. Several Wee1 inhibitors (Wee1i) are under active development in both preclinical and clinical studies. They have shown efficacy in multiple cancer types as monotherapy or as a combination with chemotherapies or targeted therapies. These studies suggest that a broader combination potential for Wee1i should be explored. Machine learning-based methods are promising and efficient approaches to model drug combination in a broader combination space. Here we have integrated two large combination studies and applied a tensor reconstruction based polynomial regression (comboLTR) method to predict the combination effects for Wee1i in expanded combinations. This work supports a machine learning approach in generating novel combination hypotheses in an expanded space from existing experimental data. Method: Two large published screening studies containing the Wee1i were normalized and integrated. This resulted in a combined screening study of 131 drugs and 53 cell line models. ComboLTR was applied to train drug combination response prediction models using collected known drug combination responses, drug molecular fingerprints, and model genomic features. The model performance was evaluated under different prediction scenarios, including the prediction of missing entries in a dose-response matrix and the prediction of entire dose-response matrices in new cell lines or with unknown drugs. The hyper-parameters were tuned separately for different prediction scenarios to reach the best performance. Three different synergy scores (HSA, Bliss, Loewe) were used to summarize the synergy effects of the predicted drug combinations. The average of the synergy scores was used to evaluate the combination partners for Wee1i. Results: We integrated drug combination response data from two publications and trained LTR models based on the data. In 5-fold cross-validations for the different prediction scenarios, new entry, new matrix, new drug combo, the model achieved a Pearson correlation of above 0.8 between predicted and measured response data. The final model was trained to predict responses of drug combinations between Wee1i and 130 other drugs in 53 cell lines. Based on these predictions, we calculated synergy scores for each drug combination and cell line triplet and ranked the synergy effect within each cancer type. Several compounds reported to be synergistic with Wee1i in selected cancer types were reproduced in the prediction, including dasatinib in ovarian cancer, SN38 in breast cancer, and CHK1i in ovarian cancer. The model also predicted these compounds as having synergistic effects with Wee1i in potential new cancer types which may be of future interest. Citation Format: Tianduanyi Wang, Juho Rousu, Lin Tang. Machine learning-based combination prediction for Wee1 inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 3660.

Abstract 2118: ABN501: A CLDN3-targeted monoclonal antibody with proven safety, pharmacokinetics, and synergistic anti-tumor efficacy

Abstract ABN501 is an afucosylated monoclonal antibody specifically designed to target claudin-3 (CLDN3), a protein frequently overexpressed in various solid tumors, including small-cell lung cancer (SCLC). Given the critical role of CLDN3 in cancer cell proliferation and tumorigenesis, it is recognized as a promising therapeutic target. In this study, we evaluated the preclinical safety and efficacy of ABN501, focusing on its potential for clinical development as a targeted cancer therapy. To identify suitable animal models for toxicity assessment, we investigated the cross-species reactivity of ABN501 with CLDN3. Our results confirmed that ABN501 binds to CLDN3 across human, mouse, rat, and cynomolgus monkey species. Based on these findings, rats and cynomolgus monkeys were selected for comprehensive toxicity evaluations, including single-dose and repeated-dose studies. Notably, even at the highest administered doses, ABN501 exhibited no significant changes in key toxicity markers, demonstrating its exceptional safety profile. We further assessed the therapeutic potential of ABN501 as both monotherapy and in combination with chemotherapy. Chemotherapy was shown to upregulate CLDN3 expression in lung cancer cell lines, thereby enhancing the antitumor activity of ABN501 and confirming a synergistic effect. In conclusion, our preclinical studies demonstrate that ABN501 is a safe and effective CLDN3-targeting monoclonal antibody for treating CLDN3-overexpressing cancers. Its excellent safety profile and synergistic effects in combination with chemotherapy present a promising strategy for improving treatment outcomes, particularly in cancers with limited targeted treatment options. These findings pave the way for further clinical investigation, particularly in lung cancer and other CLDN3-expressing malignancies. Citation Format: Saehyung Lee, Jae Choi, Sunghyun Hong, Ha Yeon Park, Ho Jin Lee, Jaemun Kim, Sangin Lee, Seung Hwa Jung, Myeung Ryun Seo, Hobin Yang, Sungyoul Hong, Jun Young Choi, Na Young Kim, Young Kee Shin. ABN501: A CLDN3-targeted monoclonal antibody with proven safety, pharmacokinetics, and synergistic anti-tumor efficacy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2118.

Abstract 6002: Tyrosine kinase inhibitor (TKI) plus PD-1 blockade in TKI-responsive MSS/pMMR metastatic colorectal adenocarcinoma (mCRC): Results of a multicenter, phase II trial (TRAP)

Abstract Background: There is an unmet need in immunotherapy for patients (pts) with MSS/pMMR mCRC. PD-1 blockade combined with antiangiogenic therapy has synergistic effects and has shown clinical benefits in these pts in several studies. TRAP (NCT04483219) aims to explore the efficacy and safety of antiangiogenic TKIs combined with PD-1 blockade in TKI-responsive MSS/pMMR mCRC pts refractory to standard treatment. Methods: Eligible pts were given 1 cycle of TKIs (fruquintinib 5mg or regorafenib 120mg, d1-21, q4w) and grouped by tumor response according to RECIST v1.1: arm A: reduction of target lesion to CR, PR or shrunken SD, or cavitation in metastatic lung lesions, or decrease in the density of liver metastatic target lesions ≥15%; arm B: enlarged SD; arm C: PD. Then arm B pts were given another cycle of TKIs and grouped again. Pts in arm A then received TKIs plus anti-PD-1 antibody (toripalimab 240mg, or sintilimab 200mg, i.v.gtt, q3w, until PD or up to 2 years), pts in arm B continued with TKIs until PD. The Simon 2-stage design tested the null 9-months (m) PFS rate of 27.1% vs. 55% (power = 0.90; α = 0.05). A total of >10 pts reaching ≥ 9-m PFS in 25 pts receiving TKI plus anti-PD-1 antibody is required to reject null hypothesis. Results: As of Sep 16, 2024 (data cutoff), 58 eligible pts were enrolled. Median age, 60 (34-75); male, 56.9%; ECOG PS 1, 96.6%; KRAS mutation, 48.3%; median prior regimens, 2 (1-4); prior anti-VEGF, 73.7%; prior anti-EGFR, 28.1%. 25 pts entered arm A and 29 entered arm C. Baseline characteristics of arm A were generally consistent with the overall population. In arm A, ORR was 20.0% (95%CI, 6.8%-40.7%). Median PFS was 11.5m (95% CI, 7.31-18.9), 6-m, 9-m and 12-m PFS rates were 87.1% (95% CI, 74.4%-100%), 58.1% (95% CI, 40.4%-83.4%) and 42.6% (95% CI, 25.7%-70.6%), respectively. At median follow-up of 31.1m (95% CI, 29.0-NA), median OS was 24.7m (95% CI, 17.0-NA), 12-m, 24-m and 36-m OS rates were 82.4% (95% CI, 68.1%-99.7%), 53.3% (95% CI, 35.6%-79.6%) and 35.5% (95% CI, 19.2%-65.5%), respectively. Median PFS and median OS were numerically longer in fruquintinib versus regorafenib treated pts (13.21m [95%Cl: 7.31-NA] vs 8.95m [95%CI: 6.82-NA], p=0.38; 29.0m [95%Cl: 17.0-NA] vs 19.5m [95%CI: 16.9-NA], p=54) and in KRAS wild-type and KRAS mutant pts (13.21m [95%CI: 8.95-NA] vs 7.31m [95%Cl: 4.85-NA], p=0.21; 26.6m [95%CI: 17.9-NA] vs 15.0m [95%Cl: 14.2-NA], p=0.24). The most common treatment-related adverse events (TRAEs) (total; Grade ≥3) were hand-foot skin reaction (43.8%; 18.8%), hypothyroidism (37.5%; 6.3%), hypertension (31.2%; 25.0%) and proteinuria (31.2%; 6.3%). No treatment related death was observed. Conclusions: TKIs combined with PD-1 blockade has shown encouraging efficacy with acceptable toxicities in MSS/pMMR mCRC pts responsive to TKI treatment. The regimen could be a preferred approach in pretreated MSS/pMMR mCRC. Citation Format: Jingdong Zhang, Qian Dong, Yuanhe Wang, Yanwen Diao, Xiujie Cui, Li Man, Jian Zhang, Yuyang Zhang, Tao Wu, Tiejun Chen, Yuyang Dong, Junwei Zhang, Yanyuan Huang, Siliang Wang. Tyrosine kinase inhibitor (TKI) plus PD-1 blockade in TKI-responsive MSS/pMMR metastatic colorectal adenocarcinoma (mCRC): Results of a multicenter, phase II trial (TRAP) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 6002.