Oncogene In Cancer Research Articles

Transcription factor KLF5 regulates MsrB1 to promote colorectal cancer progression by inhibiting ferroptosis through β-catenin.

Transcription factor KLF5 regulates MsrB1 to promote colorectal cancer progression by inhibiting ferroptosis through β-catenin.

Site-directed antibodies targeting driver mutations of the KRAS protein.

Site-directed antibodies targeting driver mutations of the KRAS protein.

RBM5 recruiting MGC32805 in a sandwich mode and inducing ΔFAS neoantigen and triggering FAS properties switch: implication in colorectal cancer.

Pre-mRNA alternative splicing (AS) is a crucial process, which plays a significant role in inducing tumor subtype-specific alterations and the hallmark of epigenetic heterogeneity in tumorigenesis. However, the regulatory mechanisms of pre-mRNA AS remain obscure. This study demonstrates that splicing factor RBM5 recruits long non-coding RNA MGC32805, and they act in concert as oncogenes in colorectal cancer (CRC) cells by preventing apoptosis, as well as promoting migration and resistance to 5-Fluorouracil (5-FU). Specifically, they promote the exclusion of exon 6 in the FAS pre-mRNA, leading to decreased expression of mFAS (an apoptotic isoform) and increased expression of ΔFAS (an anti-apoptotic isoform) in both CRC cells and a mouse xenograft model. RBM5, which contains Leu650 and Arg681 residues in the ZnF-C2H2 domain, recognizes the "GUACG" (-1299 to -1303) motif in MGC32805. Furthermore, MGC32805 blocks the binding site (Lys645) of the E3 ubiquitin ligase PRPF19, which targets RBM5 for degradation, thus increasing the stability of RBM5. The His665 and Leu668 residues of RBM5 specifically bind to the FAS exon 6 adjacent element (GAACAAA), which drives FAS-AS events and increases the expression ratio of the ΔFAS/mFAS isoforms. These findings introduce a novel research strategy to investigate the epigenetic heterogeneity and plasticity of tumorigenesis. They also shed light on the mechanism of MGC32805-mediated transformation of the FAS tumor neoantigen function from a tumor suppressor to an oncogene at the AS level through its interactions with RBM5.

Targeting super-enhancers in liver cancer: from pathogenic mechanisms to clinical applications.

Liver cancer, especially primary liver cancer (PLC), stands as the third leading cause of cancer-related mortality globally, posing a significant threat to human health. Super-enhancers (SEs), clusters of enhancer elements with high histone modifications and transcriptional activity levels, play crucial roles in diverse biological processes and are closely associated with the pathogenesis of various diseases, including liver cancer. This review first delves into the pathogenic mechanisms of super - enhancers in liver cancer. SEs can drive the aberrant expression of oncogenes in liver cancer. Through interactions with transcription factors and chromatin-modifying enzymes, SEs can reshape the chromatin architecture, facilitating the access of transcriptional machinery to oncogene promoters and resulting in their overexpression. Additionally, abnormal activation of signaling pathways in liver cancer can also regulate the formation and activity of SEs, creating a positive - feedback loop that fuels tumor development. We further explore how targeting SEs may translate into clinical applications for liver cancer. Therapeutic strategies, such as using small inhibitors that disrupt the function of key components in SE-mediated transcriptional complexes, have shown promise in pre-clinical studies. These inhibitors can specifically block the activity of SEs, leading to the downregulation of oncogene expression and subsequent suppression of tumor cell growth. In addition, gene-editing technologies provide new tools for precisely modulating super-enhancer activity in liver cancer cells. By deleting or modifying specific enhancer elements within SEs, the expression of oncogenes can be effectively controlled. In conclusion, understanding the pathogenic mechanisms of SEs in liver cancer and their clinical applications offers a new perspective on the diagnosis, treatment, and prognosis of liver cancer. However, more in-depth research is required to fully realize the potential of super-enhancer-targeted therapy in clinical settings in order to provide more effective treatment options for liver cancer patients.

Regulation of Stemness by NR1D2 in Colorectal Cancer

Background: Nuclear Receptor Subfamily 1 Group D Member 2 (NR1D2), a transcription factor that regulates the circadian clock, has been described as an oncogene in colorectal cancer (CRC). In several types of cancer, NR1D2 regulates cancer progression and relapse through cancer stem cells (CSCs), although this aspect has not been studied in CRC. On the other hand, p53 is a tumour suppressor gene that appears mutated in approximately a 50% CRCs. Interestingly, p53 is considered to be a crucial nexus between circadian clock deregulation and cancer. In addition, p53 regulates CSC phenotypes. Methods: We developed an in vitro model in which NR1D2 was silenced in three isogenic cell lines with different p53 status. In addition, we analysed the expression of NR1D2 in a cohort of patients and determined its relationship with the characteristics of patients and tumours. Results: In the in vitro model, NRID2 silencing reduces cell growth and decreases stemness, although only in cells harbouring a wild type p53. In contrast, in cells lacking a functional p53 or harbouring a mutated one, NR1D2 knockout increases cell growth and stemness. In patients, NR1D2 expression correlates with poorly differentiated tumours and high expression of CSCs markers, although only in tumours with a wild type p53, corroborating the results obtained in the in vitro model. Conclusions: Although more research is needed to analyse the mechanism by which NR1D2 regulates stemness in a p53-dependent manner, our results highlight the possibility of using NR1D2 antagonists for treating this type of patient and to develop personalised medicine.

NUCKS1 promotes invasion and metastasis of colorectal cancer by stabilizing HDAC2 and activating AKT

Nuclear ubiquitous casein and cyclin-dependent kinase substrate 1 (NUCKS1) functions as an oncogene in colorectal cancer (CRC), promotes the progression of CRC, and is associated with poor prognosis in patients. Studies have found that NUCKS1 promotes tumor cell metastasis, yet its role in CRC invasion and metastasis remains unclear. Our findings revealed higher NUCKS1 expression in metastatic CRC compared to non-metastatic samples. Upregulation of NUCKS1 expression promoted the migration and invasion of CRC cells, while knockdown of NUCKS1 significantly inhibited the migration and invasion of CRC cells. Mechanistically, NUCKS1 was initially found to upregulate HDAC2 expression by inhibiting the lysosomal pathway, activating AKT, and thus promoting CRC invasion and metastasis. Moreover, HDAC2 inhibitor Santacruzamate A or AKT inhibitor LY294002 rescued the migration and invasion of CRC cells caused by NUCKS1 overexpression. In vivo, by injecting CRC cells into the tail vein of a nude mouse model, we found that overexpression of NUCKS1-induced lung and liver metastasis was suppressed by HDAC2 knockdown or intraperitoneal administration of the HDAC2 inhibitor Santacruzamate A. Meanwhile, AKT inhibitor LY294002 significantly inhibited lung and liver metastasis caused by overexpression of HDAC2. The expression levels of NUCKS1, HDAC2, and phosphorylated AKT were significantly positively correlated in human CRC tissues. These findings suggest that NUCKS1 contributes to CRC invasion and metastasis by stabilizing HDAC2 and activating AKT, highlighting NUCKS1 and HDAC2 as potential therapeutic targets for CRC.

Abstract P5-06-16: Preclinical Characterization of LAE118, a Novel Allosteric Pan-mutant Selective PI3Kα Inhibitor

Abstract PIK3CA is one of the most frequently mutated oncogenes in cancer, found in approximately 13% human cancers. PI3Kα mutations are prevalent in patients with breast, colorectal, lung, endometrial, and numerous other cancers. Three hotspot mutations (H1047R, E545K, E542K) on the p110α subunit of PI3Kα are recognized activating mutations accounting for approximately 1/3 of all PI3Kα mutations. Targeting PI3Kα in cancer has been validated as a therapeutic strategy, as evidenced by the approved drug Alpelisib and the positive clincal trial result of Inavolisib, demonstrating clinical efficacy either alone or in combincation with other therapies. However, treament with non-mutant selective inhibitors raises tolerability concerns such as hyperglycimea, due to the inhibition of wild type PI3Kα. Moreover, the clinical use of PI3Kα orthosteric inhibitors, such as Alpelisib and Invaolvisib, has led to the emergency of secondary mutations (e.g. Q859K & W780R) in the ATP binding pocket resulting in resistance to these drugs. Therefore, there is a pressing need to develop novel PI3Kα-targeted therapies that can minimize on-target toxicities and overcome drug ressistance. LAE118 is a novel allosteric pan-mutant selective PI3Kα inhibitor. LAE118 demonstrates excellent in vitro anti-proliferation activities in PI3Kα mutant cell lines and remains active against cells resistant to orthosteric PI3Kα inhibitors. LAE118 shows strong anti-tumor growth effect in Xenograft models at a dose that is much lower than other allosteric inhibitors and has less effect on glucose homeostasis compared to orthosteric inhibitors. In pre-clinical toxicology studies, LAE118 also demonstrated good tolerability. These data indicate that LAE118 offers improved efficacy and larger safety window. LAE118 is currently in IND enabling stage. Citation Format: Ming Li, Ruipeng Zhang, Junyan Chen, Meijuan Hu, Xiaofen Lin, Justin Gu. Preclinical Characterization of LAE118, a Novel Allosteric Pan-mutant Selective PI3Kα Inhibitor [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2024; 2024 Dec 10-13; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(12 Suppl):Abstract nr P5-06-16.

Abstract P5-02-24: Targeting FOXK2 signaling in breast cancers with FOXK2 amplification/overexpression and PIK3CA oncogenic mutations: a promising therapeutic strategy?

Abstract Oncogene activation through DNA amplification or overexpression plays a critical role in cancer initiation and progression. Chromosome 17 harbors numerous cancer-associated genetic anomalies, some of which are strongly linked to poor prognosis in breast cancer patients. The FOXK2 gene, located on 17q25, encodes a transcription factor with a forkhead DNA binding domain. Integrative analyses of publicly available genomic datasets reveal that FOXK2 is frequently amplified and overexpressed in breast cancer, correlating with poor overall survival. FOXK2 knockdown via shRNA significantly inhibited the proliferation, migration, and anchorage-independent growth of breast cancer cells, causing G0/G1 cell cycle arrest. The C-terminal nuclear localization signal (NLS) is crucial for FOXK2's oncological function. Additionally, FOXK2 knockdown in MCF7 breast cancer cells delayed tumor growth in a xenograft mouse model. Inhibiting FOXK2 expression also sensitized breast cancer cells to frontline chemotherapy agents, including doxorubicin, 5-fluorouracil, and etoposide in vitro. Co-overexpression of FOXK2 and PI3KCA with oncogenic mutations (E545K or H1047R) induced the transformation of non-tumorigenic MCF-10A cells, suggesting that FOXK2 acts as an oncogene in breast cancer and contributes to PI3KCA-driven tumorigenesis. CCNE2, PDK1, and ESR1 were identified as direct transcriptional targets of FOXK2 in MCF-7 cells. Moreover, co-inhibition of FOXK2 function, either through knockdown or inhibition of its transcriptional targets (CCNE2/CDK2 by Dinaciclib or PDK1 by DCA) and PI3KCA by alpelisib, had synergistic anti-tumor effects in breast cancer cells with FOXK2 overexpression and PI3KCA oncogenic mutations. FOXK2 functional inhibition by the CDK2 inhibitor Dinaciclib enhanced the tumor-suppressive effect of alpelisib in a MCF7 breast cancer xenograft mouse model. These findings provide compelling evidence that FOXK2 plays an oncogenic role in breast tumorigenesis. The combination of PIK3CA and CCNE2/CDK2 inhibition by alpelisib and Dinaciclib offers a potential therapeutic strategy for breast cancer with FOXK2 overexpression and PIK3CA oncogenic mutation. Citation Format: Hong Zhang, Yang Yu, Weng-Ming Cao, Feng Cheng, Edaise da silva, Higinio Dopeso, Hui Chen, Xiaosong Wang, Chunchao Zhang. Targeting FOXK2 signaling in breast cancers with FOXK2 amplification/overexpression and PIK3CA oncogenic mutations: a promising therapeutic strategy? [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2024; 2024 Dec 10-13; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(12 Suppl):Abstract nr P5-02-24.

Abstract P3-02-27: circAXIN1 promotes EMT-mediated metastasis and doxorubicin resistance via Wnt/β-catenin pathway by regulating miR-486-3p/BCL11A axis in TNBC

Abstract Circular RNAs (circRNAs) represent a novel type of regulatory RNA characterized by high evolutionary conservation and stability. CircRNAs are expected to be potential diagnostic biomarkers and therapeutic targets for various malignancies. However, the regulatory functions and underlying mechanisms of circRNAs in triple-negative breast cancer (TNBC) are largely unknown. Using a high-throughput microarray assay, this study identified a novel circRNA, circAXIN1(hsa_circ_0005838), which was upregulated in TNBC tissues and cell lines. We found that circAXIN1 expression was increased in doxorubicin-resistance TNBC tissues and cells. Functionally, we demonstrated that circAXIN1 significantly promoted epithelial-mesenchymal transition(EMT)-mediated cell migration and invasion and enhanced doxorubicin resistance in vitro and in vivo. Mechanistically, RNA pull-down assay, RNA immunoprecipitation, and dual luciferase reporter assay disclosed that circAXIN1 was identified as a miR-486-3p sponge. We also found that BCL11A was a direct target of miR-486-3p, which functioned as an oncogene in breast cancer. Thereby, circAXIN1 upregulated BCL11A protein expression and accelerate TNBC progression. The rescue experiments also revealed that miR-486-3p overexpression or BCL11A knockdown partially reversed the regulatory functions of circAXIN1 on TNBC cell migration, invasion, and doxorubicin resistance. Furthermore, we showed that circAXIN1 promoted BCL11A expression via competitive interaction with miR-486-3p and then activated the Wnt/β-catenin signaling pathway. Additionally, in vitro and in vivo functional experiments demonstrated that circAXIN1/miR-486-3p/BCL11A axis promoted TNBC EMT-mediated metastasis and doxorubicin resistance via activating the Wnt/β-catenin signaling pathway. Collectively, our findings clarified a hitherto unexplored mechanism of the circAXIN1/miR-486-3p/BCL11A axis in EMT-mediated tumor metastasis and doxorubicin resistance in TNBC. Citation Format: Yan Liu, Shichao Zhang, Xinyu Liu, Shunan Wang. circAXIN1 promotes EMT-mediated metastasis and doxorubicin resistance via Wnt/β-catenin pathway by regulating miR-486-3p/BCL11A axis in TNBC [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2024; 2024 Dec 10-13; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(12 Suppl):Abstract nr P3-02-27.

Actin-Like Protein 6A as an Oncogene and Therapeutic Target in Cancer

Actin-Like Protein 6A as an Oncogene and Therapeutic Target in Cancer

Functional Characterization of Variants of Unknown Significance of Fibroblast Growth Factor Receptors 1-4 and Comparison With AI Model–Based Prediction

PURPOSEFibroblast growth factor receptors (FGFRs; FGFR1, FGFR2, FGFR3, FGFR4) are frequently mutated oncogenes in solid cancers. The oncogenic potential of FGFR rearrangements and few hotspot point mutations is well established, but the majority of variants resulting from point mutations especially outside of the tyrosine kinase domain are currently considered variants of unknown significance (VUS).MATERIALS AND METHODSRecurrent nonkinase domain FGFR VUS variants were collected from the Catalog of Somatic Mutations in Cancer and their oncogenic potential was assessed in vitro by different functional assays. We compiled published clinical and preclinical data on FGFR variants and compared the data with results from our functional assays and pathogenicity predictions of state-of-the-art artificial intelligence (AI) models.RESULTSWe identified 12 novel FGFR extracellular small variants with potential driver function. Comparison of clinical and preclinical data on FGFR variants with pathogenicity predictions of state-of-the-art AI models showed limited usefulness of the AI predictions. Sensitivity profiles of activating FGFR variants to targeted inhibitors were recorded and showed good targetability of FGFR nonkinase domain variants.CONCLUSIONThe collected results extend the spectrum of suitable FGFR variants for potential treatment with FGFR inhibitors in the context of clinical trials and beyond. Current AI models for variant pathogenicity prediction require further refinement for use in oncogenic decision making.

The clinicopathological characteristics of co-mutations in exon 2 and 3 of the KRAS gene in patients with colorectal cancer.

The clinicopathological characteristics of co-mutations in exon 2 and 3 of the KRAS gene in patients with colorectal cancer.

PRMT1 promotes immune escape in hepatocellular carcinoma by regulating arginine methylation modification of MYC protein

ABSTRACT Arginine methyltransferase 1 (PRMT1) is widely recognized as an oncogene in various cancers. However, its specific role and underlying mechanisms in hepatocellular carcinoma (HCC) remain insufficiently understood. This study investigated the function of PRMT1 in HCC development and immune evasion. A comprehensive approach combining database analysis (including TCGA, The Human Protein Atlas, Kaplan-Meier Plotter, and TIMER2.0), molecular techniques (such as RT-qPCR, Western blot analysis, and co-immunoprecipitation), cell-based assays (including MTT, colony formation, transwell, and T cell killing assays), and in vivo models was employed to explore PRMT1’s role in HCC. The findings revealed a marked upregulation of PRMT1 in both HCC clinical samples and cell lines. Depletion of PRMT1 inhibited cell proliferation and immune evasion while reducing cell migration and invasion. Mechanistically, PRMT1 was shown to interact with MYC, facilitating its arginine methylation and enhancing its protein stability. Moreover, re-expression of MYC significantly reversed the anti-tumour effects associated with PRMT1 depletion. In vivo experiments further corroborated these results. Collectively, PRMT1 promotes HCC progression and immune escape by mediating ADMA methylation of MYC, thereby regulating its stability and expression.

Abstract ND01: AMG 410: An H/NRAS-sparing pan-KRAS inhibitor with dual GTP(on)/GDP(off)-state activity for the treatment of diverse KRAS-mutant tumors

Abstract KRAS is one of the most frequently mutated oncogenes in human cancer (present in ∼25% of cancers). Recent approvals of covalent KRAS G12C inhibitors (KRAS G12Ci) have demonstrated that this once “undruggable” target can now be inhibited with small-molecule allosteric inhibitors to deliver meaningful clinical benefit. Approved inhibitors (sotorasib & adagrasib) are only effective for tumors harboring the KRAS G12C mutation, however, and major unmet need remains for the larger population of patients (∼140k patients/year, USA) that bear other oncogenic KRAS mutations (e.g., KRAS G12D, G12V, etc.). Leveraging insights from KRAS G12Ci, we here report the structure- and property-based design of a non-covalent “pan-KRAS” inhibitor, AMG 410, which binds to the most clinically relevant KRAS mutants (e.g., G12D, G12V, G13D; IC50 values = 1-4 nM) via the same allosteric pocket employed by approved KRAS G12C inhibitors. AMG 410 shows potent antiproliferative activity in KRAS-mutant cells (median IC50 = 12 nM). Importantly, AMG 410 is highly specific for KRAS, demonstrating greater than 100-fold selectivity against both HRAS and NRAS, differentiating AMG 410 from pan-RAS inhibitors through its ability to avoid anti-proliferative effects in non-KRAS-transformed cells (median IC50 >5 µM). In contrast to “on”-state-only inhibitors, AMG 410 is a dual GTP(on)- and GDP(off)-state inhibitor (KD(GDP-state) = 1 nM; KD(GTP-state) = 22 nM), enabling blockade of KRAS signaling in a cycling state-independent manner, while also allowing AMG 410 to block proliferation in wildtype KRAS-amplified tumor cells. AMG 410 demonstrates strong pre-clinical efficacy, robustly lowing phosphorylated ERK levels throughout dosing cycles and achieving tumor stasis or regression across a broad set of colorectal, pancreatic, and lung cancer cell line-derived xenograft (CDX) and patient-derived xenograft (PDX) models harboring a diverse set of KRAS mutant alleles including G12D, G12V, G12C, & G13D. AMG 410 also shows enhanced in vivo efficacy in combination with other targeted therapies or immunotherapy and good pre-clinical tolerability, highlighting the potential of an HRAS- and NRAS-sparing pan-KRAS inhibitor to show improved efficacy and clinical tolerability in the combination setting. Based on a promising non-clinical safety and efficacy profile, a first-in-human study with AMG 410 in a range of solid tumor indications (CRC, PDAC, NSCLC) is planned. Citation Format: Brian A. Lanman, Ryan P. Wurz, Rati Verma, Tao Osgood, Kevin Gaida, Deanna Mohn, Ying-Chu Chen, Gilbert Diaz, Anne Y. Saiki, Paul E. Hughes, Christopher Mohr, Amit Vaish, Yanyan Tudor, Upendra P. Dahal, Prashant Agarwal, Christine Mollica. AMG 410: An H/NRAS-sparing pan-KRAS inhibitor with dual GTP(on)/GDP(off)-state activity for the treatment of diverse KRAS-mutant tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_2):Abstract nr ND01.

Blocking C-terminal processing of KRAS4b via a direct covalent attack on the CaaX-box cysteine

RAS is the most frequently mutated oncogene in cancer. RAS proteins show high sequence similarities in their G-domains but are significantly different in their C-terminal hypervariable regions (HVR). These regions interact with the cell membrane via lipid anchors that result from posttranslational modifications (PTM) of cysteine residues. KRAS4b is unique as it has only one cysteine that undergoes PTM, C185. Small molecule covalent modification of C185 would block any form of prenylation and subsequently inhibit attachment of KRAS4b to the cell membrane, blocking its biological activity. We translated this concept to the discovery and development of disulfide tethering screen hits into irreversible covalent modifiers of C185. These compounds inhibited proliferation of KRAS4b-driven mouse embryonic fibroblasts, but not cells driven by N-myristoylated KRAS4b that harbor a C185S mutation and are not dependent on C185 prenylation. Top-down proteomics was used to confirm target engagement in cells. These compounds bind in a pocket formed when the HVR folds back between helix 3 and 4 in the G-domain (HVR-α3-α4). This interaction can happen in the absence of small molecules as predicted by molecular dynamics simulations and is stabilized in the presence of C185 binders as confirmed by small-angle X-ray scattering and solution NMR. NOESY-HSQC, an NMR approach that measures internuclear distances of 6 Å or less, and structure analysis identified the critical residues and interactions that define the HVR-α3-α4 pocket. Further development of compounds that bind to this pocket could be the basis of a new approach to targeting KRAS cancers.

SLC7A11-HSPB1 Axis: A Novel Mechanism for Hepatocellular Carcinoma Progression and Ferroptosis Regulation.

SLC7A11-HSPB1 Axis: A Novel Mechanism for Hepatocellular Carcinoma Progression and Ferroptosis Regulation.

EZH2: A Crucial Competing Endogenous RNA in Cancer Research-A Scoping Review.

Recently, research on the competing endogenous RNAs (ceRNAs) in cancer has been in full swing, emphasizing their importance as critical RNAs in cancer progression. Enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2) is a ceRNA that has been introduced as a potential therapeutic target in many cancers. Due to EZH2's dual role as an oncogene and tumor suppressor in cancer, a more thorough exploration of its ceRNA functions may enhance clinical cancer treatment approaches. In the current scoping review, we searched several online databases to identify experimentally validated ceRNA axes, including EZH2 in human cancers. We identified 66 unique axes consisting of 30 microRNAs (miRNAs), 32 long non-coding RNAs (lncRNAs), 9 messenger RNAs (mRNAs), and 14 circular RNAs (circRNAs). Notably, SPRY4-IT1 - miR-101-3p - EZH2 and XIST - miR-101-3p - EZH2 were recurrent axes observed in multiple cancer types. Among the most frequent miRNAs were miR-101-3p, miR-144-3p and miR-124-3p, and ceRNAs including SPRY4-IT1, XIST, SNHG6, HOXA11-AS, MALAT1, and TUG1 emerged as frequent competitors of EZH2 for miRNA binding. This scoping review highlights the diversity of EZH2-containing ceRNA axes in cancer, suggesting their potential as therapeutic targets. Further studies are needed to clarify their roles and clinical utility.

MARCH8 ubiquitinates and degrades CEMIP to induce colorectal cancer cell ferroptosis through inactivating PI3K/AKT pathway.

MARCH8 ubiquitinates and degrades CEMIP to induce colorectal cancer cell ferroptosis through inactivating PI3K/AKT pathway.

YAP-mediated DDX3X confers resistance to ferroptosis in breast cancer cells by reducing lipid peroxidation.

YAP-mediated DDX3X confers resistance to ferroptosis in breast cancer cells by reducing lipid peroxidation.

Abstract 1675: Evaluation of combination strategies with RAS-targeted inhibitors in multi-cell type spheroids

Abstract RAS genes are among the most frequently mutated oncogenes in cancer. Though previously considered undruggable, agents have recently been developed that specifically target RAS. The agents can be categorized as (1) those that selectively target specific RAS oncoproteins and (2) pan-RAS inhibitors that target a wide range of RAS alterations, including oncogenic variants and amplifications. This study evaluated the activity of four novel RAS-targeted inhibitors in combination with other targeted agents in thirty solid tumor cell lines of diverse cancer types. These included twenty-six patient-derived cancer cell lines from the NCI Patient-Derived Models Repository (https://pdmr.cancer.gov/) and four established cell lines. The cells were grown as multi-cell type (mct) tumor spheroids from 60% malignant cells, 25% endothelial cells, and 15% mesenchymal stem cells. All agents were tested at concentrations up to the clinical Cmax value, if known or 10 µM. As single agents, the KRAS-G12C inhibitors RMC-6291 and divarasib, along with the KRAS-G12D inhibitor MRTX-1133, demonstrated selective activity against the mct tumor spheroids harboring the targeted variants. In contrast, the pan-RAS(ON) inhibitor RMC-6236 demonstrated activity against the mct tumor spheroids harboring a range of KRAS variants or wild-type KRAS. When used in combination, each of the four RAS-targeted inhibitors exhibited strong synergistic effects with SHP2 inhibitors as determined by the Bliss independence model and reductions in cell viability and spheroid volume. In tumor models harboring different KRAS variants, the pan-RAS(ON) inhibitor showed increased cytotoxicity with the MEK inhibitor cobimetinib, as well as PI3K-AKT-mTOR pathway inhibitors, such as inavolisib (PI3Kα), ipatasertib (AKT), and sapanisertib (mTORC1/2). When the same agents were combined with variant-specific KRAS inhibitors similar effects were observed in mct tumor spheroids carrying the corresponding RAS variant. These preclinical findings might provide guidance for the selection of combination regimens with KRAS inhibitors to improve clinical efficacy. Funded by NCI Contract No. 75N91019D00024. Citation Format: Thomas S. Dexheimer, Nathan P. Coussens, Thomas E. Silvers, Eric M. Jones, Naoko Takebe, James H. Doroshow, Beverly A. Teicher. Evaluation of combination strategies with RAS-targeted inhibitors in multi-cell type spheroids [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 1675.