Pancreatic Cancer Xenograft Model Research Articles

Biological impact and therapeutic potential of a novel camptothecin derivative (FLQY2) in pancreatic cancer through inactivation of the PDK1/AKT/mTOR pathway

BackgroundCamptothecin (CPT), a pentacyclic alkaloid with antitumor properties, is derived from the Camptotheca acuminata. Topotecan and irinotecan (CPT derivatives) were first approved by the Food and Drug Administration for cancer treatment over 25 years ago and remain key anticancer drugs today. However, their use is often limited by clinical toxicity. Despite extensive development efforts, many of these derivatives have not succeeded clinically, particularly in their effectiveness against pancreatic cancer which remains modest. Aim of the studyThis study aimed to evaluate the therapeutic activity of FLQY2, a CPT derivative synthesized in our laboratory, against pancreatic cancer, comparing its efficacy and mechanism of action with those of established clinical drugs. MethodsThe cytotoxic effects of FLQY2 on cancer cells were assessed using an MTT assay. Patient-derived organoid (PDO) models were employed to compare the sensitivity of FLQY2 to existing clinical drugs across various cancers. The impact of FLQY2 on apoptosis and cell cycle arrest in Mia Paca-2 pancreatic cancer cells was examined through flow cytometry. Transcriptomic and proteomic analyses were conducted to explore the underlying mechanisms of FLQY2′s antitumor activity. Western blotting was used to determine the levels of proteins regulated by FLQY2. Additionally, the antitumor efficacy of FLQY2 in vivo was evaluated in a pancreatic cancer xenograft model. ResultsFLQY2 demonstrated (1) potent cytotoxicity; (2) superior tumor-suppressive activity in PDO models compared to current clinical drugs such as gemcitabine, 5-fluorouracil, cisplatin, paclitaxel, ivosidenib, infinitinib, and lenvatinib; (3) significantly greater tumor inhibition than paclitaxel liposomes in a pancreatic cancer xenograft model; (4) robust antitumor effects, closely associated with the inhibition of the TOP I and PDK1/AKT/mTOR signaling pathways. In vitro studies revealed that FLQY2 inhibited cell proliferation, colony formation, induced apoptosis, and caused cell cycle arrest at nanomolar concentrations. Furthermore, the combination of FLQY2 and gemcitabine exhibited significant inhibitory and synergistic effects. ConclusionThe study confirmed the involvement of topoisomerase I and the PDK1/AKT/mTOR pathways in mediating the antitumor activity of FLQY2 in treating Mia Paca-2 pancreatic cancer. Therefore, FLQY2 has potential as a novel therapeutic option for patients with pancreatic cancer.

Abstract LB268: Discovery of a potent, selective and brain penetrating PARP1 inhibitor, XZP-7797

Abstract First-generation PARP1/2 inhibitors are approved for the treatment of cancers, such as ovarian, prostate, pancreas, and breast cancers, with maximal activity against tumors harboring BRCA1/2 mutation or homologous recombination deficiency (HRD). However, PARP1/2 inhibitors in clinical use have severe hematological toxicities due to the inhibition of PARP2, which has been shown to play an important role in the survival of hematopoietic progenitor cells. Furthermore, the current data indicate that synthetic lethality with BRCA mutations is primarily caused by PARP1 inhibition and trapping, whereas PARP2 inhibition and trapping are not critical for anticancer activity. Therefore, the development of selective PARP1 inhibitors is expected to reduce the hematological adverse effects associated with PARP2 inhibition while maintaining the required efficacy. XZP-7797 is a potent, selective, and brain-penetrating PARP1 inhibitor with trapping ability. In biochemical assays, XZP-7797 is more than 1000-fold selective for PARP1 over PARP2 and other members of the PARP family, including PARP3, PARP5a, PARP5b, and PARP6. XZP-7797 can significantly inhibit MDA-MB-436 cell proliferation in vitro (IC50=2.4nM). In MDA-MB-436 tumor cells, XZP-7797 inhibits PARylation and increases γH2AX level in a concentration-dependent manner. XZP-7797 demonstrates rapid tumor regression in a dose-dependent manner in the BRCA1 mutant MDA-MB-436 breast cancer xenograft model. In a pancreatic cancer xenograft model, XZP-7797 can also significantly inhibit tumor growth. To evaluate the ability of XZP-7797 to cross the blood-brain barrier, an intracranial xenograft model of breast cancer is used. The results show that XZP-7797 can significantly inhibit the growth of intracranial tumors in mice at a dose of 10 mg/kg, demonstrating the brain-penetrating ability of XZP-7797. Additionally, XZP-7797 has great PK profiles in preclinical species after oral dosing and good ADME properties. In a 14-day toxicology study of XZP-7797 in SD Rats, XZP-7797 has no hematological adverse effects at the exposure that is 10 times higher than the exposure required to achieve superior efficacy. Citation Format: Yeqing Gao, Yuqian Lu, Bo Chen, Benke Jiang, Feng Wang, Genyan Zhang, Xifeng Ma, Dapeng Zhou, Chunmin Shi, Yunling Wang, Zhipeng Liu, Jun Sun, Huimin Zhou, Mei Xu, Jiakui Li, Bin Liu. Discovery of a potent, selective and brain penetrating PARP1 inhibitor, XZP-7797 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB268.

Abstract LB045: Exploiting biparatopic binding to deliver novel, differentiated ALPP/ALPPL2 targeting protein drug conjugates

Abstract The placental alkaline phosphatases ALPP and ALPPL2 are attractive targets for antibody and protein-drug conjugate (ADC and PDC) approaches. These GPI-anchored cell-surface proteins, which share very high sequence identity, are over-expressed in a number of different solid tumor indications including testicular, ovarian, endometrial, gastric, pancreatic and non-small cell lung cancers but have very little expression on normal adult tissues. Consequently, there is significant interest in exploiting ALPP/ALPPL2 for the development of new targeted oncology therapeutics, and an ALPP/ALPPL2 ADC, utilizing a classical full-length IgG antibody, is currently in Phase I clinical trials. The exploitation of biparatopic binding is an attractive approach for improving the therapeutic index of ADCs. This mode of target engagement increases the effective number of binding sites on the tumor cells and can promote internalisation and trafficking, thereby delivering increased efficacy for the same payload bolus and opening up patient populations with lower target expression. This can lead to a widening of the therapeutic window, by improving the efficacy achievable for a given amount of payload administered (often defined as the “platform” toxicity). For the development of biparatopic conjugates, the use of small protein domain binders offers advantages over the use of full-length antibodies, as they can readily be reformatted into a variety of biparatopic architectures to deliver homogeneous drug conjugates in high yield. Additionally, smaller protein formats have the capacity to penetrate deeper into solid tumors than large antibodies. We have identified a series of highly selective, high affinity ALPP/ALPPL2 single domain VHH binders, which target distinct epitopes on the protein and which, importantly, show no binding to the closely related ALPI or ALPL isoforms (which have high normal tissue expression). Using protein engineering approaches, a series of homogenous site-specifically labelled biparatopic PDCs have been developed employing the clinically validated vcMMAE (vedotin) payload. In pre-clinical studies, these PDC agents demonstrate excellent anti-tumor efficacy in vivo in ALPP/ALPPL2 positive cell-line derived xenograft models of gastric, pancreatic and ovarian cancer displaying a range of target expression. In benchmarking studies, lead biparatopic PDCs show increased internalisation and target-mediated in vitro cell kill potency compared to an ALPP/ALPPL2 targeting ADC. Additionally, in multiple CDX models, lead biparatopic PDCs demonstrate improved efficacy over an ALPP/ALPPL2 ADC both on a mg/kg and on a payload equivalents basis, in both single dose and multi-dose studies, providing complete regressions. Based on this excellent efficacy profile and favourable developability characteristics, preclinical development activities have been initiated. Citation Format: Graham Cotton, Estelle G. McLean, Paul Trumper, Mark Wappett, Stephanie Gatdula, Stacey Bell, Greg Papadakos, Kieron Lucas, Stephanie Burton, Chiara Saladino, Georgiana Parau, Aidan McCann, Jennifer Thom, Aaron N. Cranston, Tim Harrison. Exploiting biparatopic binding to deliver novel, differentiated ALPP/ALPPL2 targeting protein drug conjugates [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB045.

Abstract LB048: Unleashing the power of p53 mRNA therapeutics to suppress proliferation of p53 mutant tumors

Abstract The p53 protein, recognized as the guardian of the genome, plays a pivotal role in suppressing tumor formation. The TP53 gene, which encodes the p53 protein, is commonly subject to mutations and deletions in many cancer types resulting in loss of tumor suppressor activity. A significant proportion of patients diagnosed with lung, pancreatic, ovarian, and head and neck cancers exhibit the expression of mutant p53 in their tumors, correlating with unfavorable prognosis and survival outcomes.This study endeavors to assess the efficacy of therapeutic tumor suppressive mRNA which induces expression of wild-type p53 protein across diverse cancer types. Optimization of the 5’ and 3’ untranslated regions (UTRs) and the 5’ cap has been undertaken to enhance the efficient expression of p53 mRNA. The growth inhibitory potential of p53 mRNA therapy has been evaluated across p53 mutant cancer cell lines representing various cancer origins, along with normal or p53 wild-type cancer cell lines. We have substantiated that the p53 mRNA therapeutics can selectively inhibit the proliferation of p53 mutant cancer cells. Furthermore, we have confirmed that p53 mRNA treatment upregulated modulator of apoptosis (PUMA) and B-cell translocation gene 2 (BTG2) and cell cycle arrest via p21 upregulation. In vivo efficacy assessments of the lipid nanoparticle (LNP)-encapsulated p53 mRNA have been conducted in lung, pancreatic, and ovarian cancer xenograft models. Both regional intratumoral (i.t) and systemic intravenous (i.v) administrations of the p53 mRNA therapeutics have shown substantial suppression of tumor growth, leading to prolonged mouse survival. These results underscore the potential of the p53 mRNA therapeutics as a promising avenue for targeted cancer treatment, offering insights into the selective inhibition of p53 mutant cancer cells. Citation Format: Yong Ho Heo, Seung-Hyun Shin, Youngjin Han, Chang Gyu Lim, Innah Kim, Ji Hee Lee, Gunwoo Lee, Seongju Jeong, Yunjae Kim, Jooyun Byun, Daejin Kim, In Young Choi. Unleashing the power of p53 mRNA therapeutics to suppress proliferation of p53 mutant tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB048.

DR30318, a novel tri-specific T cell engager for Claudin 18.2 positive cancers immunotherapy

BackgroundClaudin 18.2 (CLDN18.2) is a highly anticipated target for solid tumor therapy, especially in advanced gastric carcinoma and pancreatic carcinoma. The T cell engager targeting CLDN18.2 represents a compelling strategy for enhancing anti-cancer efficacy.MethodsBased on the in-house screened anti-CLDN18.2 VHH, we have developed a novel tri-specific T cell engager targeting CLDN18.2 for gastric and pancreatic cancer immunotherapy. This tri-specific antibody was designed with binding to CLDN18.2, human serum albumin (HSA) and CD3 on T cells.ResultsThe DR30318 demonstrated binding affinity to CLDN18.2, HSA and CD3, and exhibited T cell-dependent cellular cytotoxicity (TDCC) activity in vitro. Pharmacokinetic analysis revealed a half-life of 22.2–28.6 h in rodents and 41.8 h in cynomolgus monkeys, respectively. The administration of DR30318 resulted in a slight increase in the levels of IL-6 and C-reactive protein (CRP) in cynomolgus monkeys. Furthermore, after incubation with human PBMCs and CLDN18.2 expressing cells, DR30318 induced TDCC activity and the production of interleukin-6 (IL-6) and interferon-gamma (IFN-γ). Notably, DR30318 demonstrated significant tumor suppression effects on gastric cancer xenograft models NUGC4/hCLDN18.2 and pancreatic cancer xenograft model BxPC3/hCLDN18.2 without affecting the body weight of mice.

Abstract 4737: The combination of the BET inhibitor JQ1 and gemcitabine induces regressions in gemcitabine resistant patient-derived xenograft models of pancreatic cancer

Abstract Efforts to develop targeted therapies for drug resistant tumors have been relatively unsuccessful. The 5-year survival for patients with advanced pancreatic cancer is ~3%. Gemcitabine is usually combined with nab-paclitaxel as a standard of care for treatment of locally advanced or metastatic pancreatic ductal adenocarcinoma (PDAC). However, no chemotherapeutic regimens thus far evaluated have been curative. We developed the first PDAC patient-derived xenograft (PDX) models in which resistance against gemcitabine was acquired in vivo. We used RNA-seq and ingenuity pathway analysis to compare expression profiles of paired parent vs gemcitabine resistant PDX models. This comparison suggested a previously unreported mechanism for gemcitabine resistance, involving aberrations of cholesterol biosynthesis and lipid metabolism pathways. We also made the unexpected observation that gemcitabine-resistant PDAC models derived from primary tumors have high levels of 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2), an enzyme essential to cholesterol biosynthesis and rate limiting in ketogenesis. Notably, the BET bromodomain inhibitor JQ1 decreases HMGCS2 levels; and BET inhibitors + gemcitabine exert synergistic cytotoxicity in gemcitabine-resistant PDAC cells. We determined that the BET bromodomain inhibitor JQ1 + gemcitabine induces regressions of two in vivo gemcitabine-resistant tumor models which we developed directly from primary human tumor tissue. These mechanism-based studies suggest that inhibiting HMGCS2 represents a novel approach to therapy for PDAC. We propose that combining gemcitabine with agents that decrease levels of HMGCS2 comprises effective treatment for patients with drug resistant PDAC. Citation Format: Aubrey L. Miller, Samuel C. Fehling, Eric Josh Brown, Eric O. Heard, Tracy L. Gamblin, Rebecca B. Vance, Karina J. Yoon. The combination of the BET inhibitor JQ1 and gemcitabine induces regressions in gemcitabine resistant patient-derived xenograft models of pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4737.

Abstract 1597: CD144+cancer-associated fibroblasts drive the malignancy of pancreatic cancer via stimulating inflammatory paracrine

Abstract Purpose: Cancer-associated fibroblasts (CAFs) are highly heterogeneous in pancreatic ductal adenocarcinoma (PDAC). We previously reported that CAFs can acquire an endothelial phenotype under stress. Thus, we hypothesized that there are CAFs highly expressing endothelial markers and substantiated a novel subtype of CAFs promoting tumor progression. Experimental design: We performed single-cell RNA sequencing to identify the existence of CD144+CAFs. The prospective and retrospective analysis were combined to figure out the correlation between CD144+CAFs proportion and clinical outcome. The proliferation and invasion assay of cell lines, organoids and pancreatic cancer xenograft model were used to detect the effect of CD144+CAFs on tumor progression. Cytokine array assay, RNA-sequencing, IP-mass spectrum, Ch-IP and luciferase analysis were conducted to elucidate the underlying mechanism. siRNA delivery nanosystem was designed and administrated to precisely target CD144+CAFs in vivo. Results: CD144+CAFs were present in tumor microenvironment of PDAC and breast cancer and patients with a higher CD144+CAFs proportion have worse prognosis in PDAC. CD144+CAFs can promote the metastasis of PDAC through enhancing epithelial-mesenchymal transition. CD144-β-catenin-STAT3 signaling axis was activated and downstream inflammatory secreted cytokines were transcriptionally upregulated to maintain the functions and phenotype of CD144+CAFs. A novel CAF-targeting siRNA delivery nanosystem, loading FAPα and siCDH5, was designed and administrated to precisely target CD144+CAFs, which substantially inhibited the protumoral roles in vivo. Conclusion: CD144+CAFs can promote the growth and metastasis of PDAC by activating CD144-β-catenin-STAT3 signaling axis and stimulating inflammatory secretion. CAF-targeting siRNA delivery nanosystem can inhibit tumor progression by precisely targeting CD144+CAFs. Citation Format: Xugang Sun, Jun Yu, Tiansuo Zhao, Jihui Hao. CD144+cancer-associated fibroblasts drive the malignancy of pancreatic cancer via stimulating inflammatory paracrine [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1597.

Abstract 3121: Therapeutic potential of a HER3 antibody-drug conjugate for the treatment of HER3-expressing cancers

Abstract To address the need for targeted therapy in the treatment of HER3-positive solid tumors, the human HER3 mAb, seribantumab, was evaluated in the context of an antibody-drug conjugate (ADC). As a proof-of-concept, seribantumab was conjugated with a cleavable valine-citrulline linker and monomethyl auristatin E (MMAE) payload via the stochastic cysteine conjugation method to yield HER3-ADC1. A drug-antibody ratio of 4 was selected for preclinical assessment in HER3-expressing models. Methods: HER3-ADC1 was evaluated in vitro and in vivo, with patritumab deruxtecan (patri-DXd) as a comparator. Binding to BT474 breast carcinoma cells (HER3 high; immunohistochemical (IHC) staining intensity 3+) was measured by flow cytometry. Internalization properties were established using seribantumab and patritumab coupled to Fab-AF488 following 4 hours incubation in SK-BR-3 breast adenocarcinoma (HER3 high; IHC 3+) and HCC1569 breast carcinoma (HER3 low; IHC 0-1+) cell lines. In vitro cytotoxicity was evaluated for HER3-ADC1, isotype-MMAE and free MMAE payload as well as patri-DXd, isotype-DXd and free deruxtecan payload in BT474 cells, SK-BR-3 cells and NCI-H446 lung carcinoma (HER3 low; IHC 0-1+) cells. In vivo anti-tumor activity was assessed for HER3-ADC1, isotype-MMAE, patri-DXd and isotype-DXd in patient derived xenograft (PDX) models of pancreatic (HER3 high; IHC 3+) and breast cancer (HER3 low; IHC 0-1+). Results: HER3-ADC1 binding to cancer cells, endocytosis, MMAE release, and inhibition of proliferation were dependent on HER3 expression. In assays investigating antibody internalization, seribantumab displayed similar internalization capacity as patritumab. For both HER3 mAbs, internalization was greater in a HER3 high than a HER3 low cell line. In cytotoxicity assays, HER3-ADC1 and patri-DXd displayed HER3 expression level-dependent cell killing. HER3-ADC1 outperformed patri-DXd in HER3 high cell lines based on in vitro cytotoxicity. HER3-ADC1 and patri-DXd were ineffective against NCI-H466 cells with low HER3 expression. In a PDX model of pancreatic cancer (HER3 high), HER3-ADC1 induced tumor regression, while isotype-MMAE had only a moderate anti-tumor effect. Both patri-DXd and isotype-DXd had moderate anti-tumor effects, indicating a lack of HER3 target dependence. In a PDX model of breast cancer (HER3 low), HER3-ADC1 and isotype-MMAE lacked anti-tumor activity; isotype-DXd had a moderate anti-tumor effect and patri-DXd had a substantial anti-tumor effect. Conclusions: HER3-ADC1 demonstrated target-dependent in vitro cytotoxicity and in vivo anti-tumor activity in a HER3-expressing pancreatic cancer PDX model. Results from in vitro and in vivo studies highlight the promising therapeutic potential of a seribantumab-based ADC for patients with HER3-expressing cancers. Additional results on the optimization and characterization of HER3-ADC1 will be presented. Citation Format: Thomas O'Hare, Jaclyn Cleveland, Valerie M. Jansen, David Dornan. Therapeutic potential of a HER3 antibody-drug conjugate for the treatment of HER3-expressing cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3121.

Abstract 6487: The selective WEE1 inhibitor azenosertib shows synergistic anti-tumor activity with KRASG12C inhibitors in multiple KRASG12C models

Abstract KRASG12C is a potent oncogenic driver which results in downstream hyperactivation of MAPK signaling and unchecked oncogenic growth, while simultaneously increasing replication stress (RS) and accumulation of DNA damage. KRASG12C-specific inhibitors are approved and/or recommended in metastatic non-small cell lung cancer (NSCLC) and colorectal cancer (CRC), and while responses are robust, some patients are inherently resistant, and most responders acquire resistance. Resistance mechanisms include reactivation of MAPK signaling, and cancer cells which escape MAPKi are reported to have high levels of genomic instability. WEE1 is a kinase involved in cell cycle progression, allowing cells to repair damaged DNA before entering the next cell cycle phase. Consequently, inhibition of WEE1 leads to premature cell cycle entry and RS, thereby driving cancer cells through the cell cycle with unchecked accumulation of DNA damage, ultimately resulting in mitotic catastrophe and cell death. We hypothesized that high levels of genomic instability and RS in KRASG12C mutant and KRASG12C inhibitor-resistant tumors present a vulnerability to WEE1 inhibition and provide rationale for combining azenosertib, a novel, selective, and orally bioavailable WEE1 inhibitor, with KRASG12C inhibitors. Here, we report azenosertib in combination with KRASG12C inhibitors as an effective therapeutic strategy for KRASG12C tumors. In vitro combination of azenosertib with multiple KRASG12C inhibitors demonstrated synergistic cell growth inhibition across a panel of KRASG12C cell lines in both 2D and 3D assays. In vivo treatment with azenosertib in KRASG12C inhibitor-sensitive cell line-derived xenograft (CDX) models of NSCLC (NCI-H358, NCI-H2122, NCI-H1792), CRC (SW837, SW1463), and pancreatic cancer (MIA PaCa-2) demonstrated significant monotherapy activity as well as synergistic tumor growth inhibition (TGI) when combined with KRASG12C inhibitors, including tumor regression in some models. Importantly, the KRASG12C inhibitor-resistant SW1573 NSCLC CDX model demonstrated synergistic TGI in the combo arm (84%) when compared against monotherapy azenosertib (31%) or adagrasib (58%). Similarly, treatment of a KRASG12C inhibitor-resistant patient-derived xenograft (PDX) model of CRC resulted in synergistic TGI in the combination arm (61%) relative to monotherapy azenosertib (17%) or adagrasib (2%). Finally, analysis of biomarkers from both in vitro and in vivo tumor samples demonstrated synergistic increases in protein markers of RS, DNA damage, and apoptosis with combination therapy. Taken together, our results suggest that the combination of azenosertib with KRASG12C inhibitors enhances tumor growth inhibition over single agent therapy and may be an effective treatment option for patients with KRASG12C tumors. Citation Format: Nathan M. Jameson, Gabriel Kim, Catherine Lee, Blake Skrable, Alexandra Shea, Monah Abed, Olivier Harismendy, Jianhui Ma, Doris Kim, Mark R. Lackner. The selective WEE1 inhibitor azenosertib shows synergistic anti-tumor activity with KRASG12C inhibitors in multiple KRASG12C models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6487.

Abstract 3137: Development of AT2604, a highly efficacious ADC targeting alkaline phosphatases ALPP and ALPPL2​

Abstract Placental alkaline phosphatases, ALPP and ALPPL2, are highly homologous, membrane-bound proteins involved in fetal development. Despite having limited expression in normal tissues, they are highly differentiated in tumor cells making them ideal targets for antibody drug conjugate (ADC) development. AT2604 is an ADC that consists of a humanized IgG1 anti-ALPP/ALPPL2 antibody that displays specificity over other human alkaline phosphatases and is cross reactive to NHP ALPPL2 but not to murine ALPPL2. The anti-ALPP/ALPPL2 antibody shows high target binding affinity and internalization into ALPP and ALPPL2 positive cells.​ AT2604 utilizes AxcynCYSTM technology for site-specific conjugation to achieve a highly homogeneous (>97%) DAR4 ADC product. The payload is the clinically validated microtubule disrupting agent monomethyl auristatin E (MMAE) conjugated to the antibody via a protease-cleavable peptide linker approved for ADC use. When evaluated in mouse xenograft models of gastric (NCI-N87) and pancreatic (HPAC) cancer, AT2604 displayed strong tumor growth inhibition (>90%) at 1 mg/kg (QW3 × 2 dosing) in both models. Furthermore, a pre-tox study in non-human primates concluded AT2604 has a HNSTD of 10 mg/kg (QW3 × 3 dosing) and did not exhibit any non-reversible adverse effects; implying that AT2604 possesses an improved safety profile over other vedotin-based ADCs. Taken together, the data supports the continued development of AT2604 towards evaluation in human trials.​ Citation Format: Bryan K. Yeung, Xiao Hui Koh, Wei Li Ling, Weiqi Tan, You Xue Wu, Xi Yun Zhang, Hong Yee Tan, Shao Jun Liu, Chen Zhong, Bin Zou. Development of AT2604, a highly efficacious ADC targeting alkaline phosphatases ALPP and ALPPL2​ [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3137.

Abstract 2795: An investigation to identify the phylogeny of bacterial communities in the pancreatic cancer microbiome by 16SrDNA sequencing and bioinformatic analysis

Abstract The microbiome refers to the diverse community of microorganisms, including bacteria, viruses, fungi, and other microbes, that inhabit various parts of the human body, such as the skin, mouth, gut, and other mucosal surfaces. The role of the microbiome in cancer is a complex and evolving area of research. While much is still being learned, there is evidence suggesting that the microbiome can influence cancer development and progression in several ways. Some bacteria within the microbiome can produce substances that may be either carcinogenic or protective against cancer. For instance, the conversion of certain dietary components by gut bacteria can produce metabolites that may either promote or inhibit cancer development. Different cancers may be associated with specific alterations in the microbiome, for example, the gut microbiome has been extensively studied in relation to colorectal cancer, with certain bacterial species potentially contributing to the development of this cancer. However, the role of microbiome in Pancreatic cancer is still not extensively studied, henceforth, we did a preliminary study to identify novel bacterial communities around pancreatic cancer microbiome by 16SrDNA sequencing in human pancreatic cancer xenograft model mice. Isolating total genomic DNA from the pancreatic model mice feces, 16SrDNA PCR was done using specific primers and the amplicon obtained as PCR product was confirmed by standard DNA gel electrophoresis with a 1 kb standard ladder to be 1.5kb in size universal for all bacterial 16SrDNA. The amplicon was then sent for Next Generation Sequencing at Zymo Research Corporation (CA). The resultant DNA sequences were analyzed by bioinformatics studies and their phylogeny identified by comparing with 16SrDNA data base. Differential abundance of the bacteria’s of the genera Lachnoclostridium, Robinsoniella, Alistipes, Akkermansia and Lactobacillus were observed analyzing the data along with other bacterial communities. We are currently continuing the project to identify more bacterial communities of significance in the pancreatic cancer microbiome and investigating the role and significance of these bacterial communities in pancreatic cancer tumor microenvironment. Acknowledgement This study was done by a joint collaboration between scientists and students of Elizabeth City State University (ECSU) campus of the University of North Carolina Systems and Mayo Clinic, Jacksonville. This research is supported by the NIH-NIGMS grant#T34GM100831-10 to Dr. H. Banerjee and a University of North Carolina General Administration Grant to Dr. Colby Hunter at ECSU. Citation Format: Hirendra N. Banerjee, Colby Hunter, Narendra Banerjee, Karrington Perry, Khadimou Dia, Anasua Banerjee, Santanu Bhattacharya, Hari Krishnareddy Rachamala, Enfang Wang, Shamit Dutta. An investigation to identify the phylogeny of bacterial communities in the pancreatic cancer microbiome by 16SrDNA sequencing and bioinformatic analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2795.

Pre-clinical Efficacy and Safety Pharmacology of PEGylated Recombinant Human Endostatin.

This study aimed to outline the pre-clinical efficacy and safety pharmacology of PEGylated recombinant human endostatin (M2ES) according to the requirements of new drug application. The purity of M2ES was evaluated by using silver staining. Transwell migration assay was applied to detect the bioactivity of M2ES in vitro. The antitumor efficacy of M2ES was evaluated in an athymic nude mouse xenograft model of pancreatic cancer (Panc-1) and gastric cancer (MNK45). BALB/C mice were treated with different doses of M2ES (6, 12 and 24 mg/kg) intravenously, both autonomic activity and cooperative sleep were monitored before and after drug administration. The apparent molecular weight of M2ES was about 50 kDa, and the purity was greater than 98%. Compared with the control group, M2ES significantly inhibits human micro-vascular endothelial cells (HMECs) migration in vitro. Notably, weekly administration of M2ES showed a significant antitumor efficacy when compared with the control group. Treatment of M2ES (24mg/kg or below) showed no obvious effect on both autonomic activity and hypnosis. On the basis of the pre-clinical efficacy and safety pharmacology data of M2ES, M2ES can be authorized to carry out further clinical studies.

IMN041 is an immunotherapeutic and an effective treatment in mouse xenograft models of pancreatic cancer, renal cancer and triple negative breast cancer

BackgroundiMN013 (5-aza-2',2'-difluorodeoxycytidine), a DNA methyl transferase inhibitor and ribonucleotide reductase inhibitor, and its prodrug iMN041 (3',5'-di-trimethylsilyl-2',2'-difluro-5- azadeoxycytidine), have been shown to be active in mouse xenograft models of hematogenous and solid tumors. In a xenograft of non-small cell lung cancer (NCI-H460), iMN041 treated mice demonstrated a marked inflammatory response upon analysis of tumor histology, which was hypothesized to be mediated by upregulation of natural killer (NK) cells. This study aimed to characterize the antitumor immune responses generated by iMN041 and test the efficacy iMN041 in solid tumors with poor prognosis.MethodsIn the Renca syngeneic mouse model, tumors were harvested following two doses of iMN041 or vehicle control, and analyzed by fluorescent-activated cell sorting for an antitumor immune response. iMN041 was also tested for tumor growth inhibition and animal survival for up to 42 days in xenograft models of pancreatic, renal, and triple negative breast cancer.ResultsTumors from mice implanted with the Renca cell line and treated with iMN041 demonstrated an increase in granzyme B in NK (p = 0.024) and NKT cells (p = 0.004), an increase in the ratios of CD8-T to regulatory T cells (Treg) (p = 0.0026) and CD4-T to Treg cells (p = 0.022) and a decrease in myeloid-derived suppressor cells (p = 0.040), compared to vehicle controls. A significant decrease in MAGE-A positive tumor cells in treated mice, concordant with a proportional decrease in all live tumor cells, suggests that these cells are one of the main targets of the activated immune system. Xenograft models of the triple negative breast cancer cell line DU4475, renal cancer cell lines 786-O and Caki-1, and pancreatic cancer cell lines CFPAC-1 and SW1990, demonstrated significantly lower tumor volumes, and, where there were a sufficient number of events, significantly improved survival in treated mice compared to vehicle control mice.ConclusionsIn mouse cancer models, iMN041 is an effective treatment for solid tumors mediated in part through a unique antitumor immune response.

Cancer-associated fibroblasts promote stemness maintenance and gemcitabine resistance via HIF-1α/miR-21 axis under hypoxic conditions in pancreatic cancer.

Gemcitabine (GEM) resistance affects chemotherapy efficacy of pancreatic cancer (PC). Cancer-associated fibroblasts (CAFs) possess the ability of regulating chemoresistance. This study probed the mechanism of hypoxia-treated CAFs regulating cell stemness and GEM resistance in PC. Miapaca-2/SW1990 were co-cultured with PC-derived CAFs under normoxic/hypoxic conditions. Cell viability/self-renewal ability was determined by MTT/sphere formation assays, respectively. Protein levels of CD44, CD133, Oct4, and Sox2 were determined by western blot. GEM tumoricidal assay was performed. PC cell GEM resistance was evaluated by MTT assay. CAFs were cultured at normoxia/hypoxia. HIF-1α and miR-21 expression levels were assessed by RT-qPCR and western blot, with their binding sites and binding relationship predicted and verified. CAF-extracellular vesicles (EVs) were incubated with Miapaca-2 cells. The RAS/AKT/ERK pathway activation was detected by western blot. PC xenograft models were established and treated with hypoxic CAF-EVs and GEM. CAFs and PC cell co-culture increased cell stemness maintenance, GEM resistance, cell viability, stem cell sphere number, and protein levels of CD44, CD133, Oct4, and Sox2, and weakened GEM tumoricidal ability to PC cells, with the effects further enhanced by hypoxia. Hypoxia induced HIF-1α and miR-21 overexpression in CAFs. Hypoxia promoted CAFs to secrete high-level miR-21 EVs via the HIF-1α/miR-21 axis, and activated the miR-21/RAS/AKT/ERK pathway. CAF-EVs promoted GEM resistance in PC via the miR-21/RAS/ATK/ERK pathway in vivo. Hypoxia promoted CAFs to secrete high-level miR-21 EVs through the HIF-1α/miR-21 axis, and activated the miR-21/RAS/AKT/ERK pathway via EVs to trigger stemness maintenance and GEM resistance in PC.

Self-assembled nanomicelles for oral delivery of luteolin utilizing the intestinal lymphatic pathway to target pancreatic cancer.

Pancreatic cancer is one of the major cause of cancer-related deaths worldwide, and is mainly associated with carcinomas of the pancreatic tissue. Current therapies for treating pancreatic cancer have a major drawback related to their low bioavailability and non-specificity, which leads to low therapeutic efficacy and side effects. Luteolin (LUT) has been clinically used for treatment of various types of cancer, although its clinical use has declined owing to its low oral bioavailability. In this work, we prepared an effervescent-based nanocarrier (NG) that rapidly triggers an effervescent reaction and transforms into nanomicelles to modulate the oral bioavailability of the hydrophobic drug Luteolin (LUT). Furthermore, we performed tests to assess its in vitro epithelial cell permeability and cellular internalization on a Caco-2 monolayer. We also performed in vivo toxicity assessment using animal models. Further, we evaluated the nanocarrier system's in vivo efficacy in tumor xenograft pancreatic cancer models. We validated that being pH responsive, our effervescent carrier disassembles at intestinal pH and is absorbed through the intestinal lymphatic system (ILS) to further site-specifically invade the pancreatic cancer cells. Furthermore, the negative surface charge and particle size (450 ± 100 nm) of the nanomicelles helped to internalize LUT through the ILS. We observed that LUT-loaded nanomicelles have significant antipancreatic cancer efficacy by activating caspase-3 activity and downregulating VEGF-A, FAK, TNF-α, and Ki-67. Unlike other drug-delivery systems, we developed noninvasive nanocarrier system has the capability of transporting the hydrophobic drug LUT from the intestine to the tumor site by utilizing the ILS.

Translational PK-PD/TD modeling of antitumor effects and peripheral neuropathy in gemcitabine and nab-paclitaxel chemotherapy from xenograft mice to patients for optimal dose and schedule.

Gemcitabine and nab-paclitaxel (GnP) treatment, the standard first-line chemotherapy for unresectable pancreatic cancer, often causes peripheral neuropathy (PN). To develop alternative dosing strategies to avoid severe PN, understanding the relationship between pharmacokinetics (PK) and pharmacodynamics/toxicodynamics (PD/TD) is necessary. We established a PK-PD/TD model of GnP treatment to develop an optimal dose schedule. A mouse xenograft model of human pancreatic cancer was generated to measure drug concentrations in the plasma and tumor, antitumor effects, and PN after GnP treatment. The Simeoni tumor growth inhibition model with tumor concentrations and empirical indirect response models were used for the PD and TD models, respectively. Clinical outcomes were predicted with reported population estimates of PK parameters in cancer patients. The PK-PD/TD model simultaneously described the observed tumor volume and paw withdrawal frequency in the von Frey test. For the standard GnP regimen, the model predicted clinical overall response (75.1%), which was overestimated compared to that in a recent phase II study (42.1%) but lower than the observed disease control rate (96.5%). Model simulation showed that dose reduction to less than 40% GnP dose was not effective; a change of dose schedule from every week for 3weeks to every 2weeks was a more favorable approach than dose reduction to 60% every week. The PK-PD/TD model-based translational approach provides a guide for optimal dose determination to avoid severe PN while maintaining antitumor effects during GnP chemotherapy. Further research is needed to enhance its applicability and potential for combination chemotherapy regimens.

Myoglobin improves doxycycline sensitivity in pancreatic cancer through promoting heme oxygenase-1-mediated ferroptosis.

Ferroptosis is expected to be a therapeutic target for cancers including pancreatic cancer. We aimed to screen genes that regulate ferroptosis and doxycycline resistance in pancreatic cancer and to explore the underlying mechanisms. Bioinformatics analysis was performed to identify genes that respond to ferroptosis in two human pancreatic cancer cells with GOT1 knocked down or not. 325 and 842 genes were upregulated in MiaPaCa and Tu8902 cells in response to GOT1 knockdown, with 43 genes shared. Among the 43 genes, 14 genes were identified to interact with ferroptosis key genes. MB and HMOX1 were the genes most sensitive to Erastin and doxycycline. Moreover, MB and HMOX1 expression was higher in human normal pancreatic duct epithelial cells than in pancreatic cancer cells. MB and HMOX1 proteins physically bound and promoted each other's expression. By interacting with HMOX1, MB suppressed pancreatic cancer cell proliferation, colony formation and invasion, and promoted cell ferroptosis and sensitivity to erastin and doxycycline. Silencing HMOX1 reversed the promoting effect of MB on cell ferroptosis and sensitivity to doxycycline. A pancreatic cancer xenograft model was established by subcutaneous injection of Panc-1 cells transfected with or without Ad-MB, and doxycycline was administered intraperitoneally. Overexpression of MB enhanced the inhibitory effect of doxycycline on xenograft growth. In conclusion, MB facilitated doxycycline sensitivity in pancreatic cancer cells through promoting HMOX1-mediated ferroptosis.

Mobilization of Circulating Tumor Cells after Short- and Long-Term FOLFIRINOX and GEM/nab-PTX Chemotherapy in Xenograft Mouse Models of Human Pancreatic Cancer.

Mobilization of CTCs after various types of therapy, such as radiation therapy, has been reported, but systematic study of CTCs after chemotherapy remained quite limited. In this study, we sequentially examined CTC numbers after single-dose and repetitive-dose chemotherapy, including FORFIRINOX (FFX) and Gemcitabine and nab-Paclitaxel (GnP) using two pancreatic cancer xenograft models. CTC was detected by the immunocytology-based microfluidic platform. We further examined the dynamic change in the histology of primary tumor tissues during chemotherapy. We confirmed a transient increase in CTCs 1-2 weeks after single-dose and repetitive-dose of FFX/GnP chemotherapy. Histological examination of the primary tumors revealed that the peak period of CTC at 1-2 weeks after chemotherapy corresponded to the maximal destructive phase consisting of cell cycle arrest, apoptosis of tumor cells, and blood vessel destruction without secondary reparative tissue reactions and regeneration of tumor cells. These findings indicate that mobilization of CTCs early after chemotherapy is mediated by the shedding of degenerated tumor cells into the disrupted blood vessels driven by the pure destructive histological changes in primary tumor tissues. These results suggest that sequential CTC monitoring during chemotherapy can be a useful liquid biopsy diagnostic tool to predict tumor chemosensitivity and resistance in preclinical and clinical settings.

TROP2-directed nanobody-drug conjugate elicited potent antitumor effect in pancreatic cancer

BackgroundPancreatic cancer is a highly aggressive malignancy with limited treatment options and a poor prognosis. Trophoblast cell surface antigen 2 (TROP2), a cell surface antigen overexpressed in the tumors of more than half of pancreatic cancer patients, has been identified as a potential target for antibody–drug conjugates (ADCs). Almost all reported TROP2-targeted ADCs are of the IgG type and have been poorly studied in pancreatic cancer. Here, we aimed to develop a novel nanobody-drug conjugate (NDC) targeting TROP2 for the treatment of pancreatic cancer.ResultsIn this study, we developed a novel TROP2-targeted NDC, HuNbTROP2-HSA-MMAE, for the treatment of TROP2-positive pancreatic cancer. HuNbTROP2-HSA-MMAE is characterized by the use of nanobodies against TROP2 and human serum albumin (HSA) and has a drug-antibody ratio of 1. HuNbTROP2-HSA-MMAE exhibited specific binding to TROP2 and was internalized into tumor cells with high endocytosis efficiency within 5 h, followed by intracellular translocation to lysosomes and release of MMAE to induce cell apoptosis in TROP2-positive pancreatic cancer cells through the caspase-3/9 pathway. In a xenograft model of pancreatic cancer, doses of 0.2 mg/kg and 1 mg/kg HuNbTROP2-HSA-MMAE demonstrated significant antitumor effects, and a dose of 5 mg/kg even eradicated the tumor.ConclusionHuNbTROP2-HSA-MMAE has desirable affinity, internalization efficiency and antitumor activity. It holds significant promise as a potential therapeutic option for the treatment of TROP2-positive pancreatic cancer.Graphical

Lactobacillus casei combined with Lactobacillus reuteri alleviate pancreatic cancer by inhibiting TLR4 to promote macrophage M1 polarization and regulate gut microbial homeostasis

BackgroundPancreatic cancer is a highly lethal disease with no effective treatments. Lactobacillus casei (L. casei) and Lactobacillus reuteri (L. reuteri) exhibited therapeutic effects on several cancers, but their roles in pancreatic cancer are unknown. This study aims to explore how L. casei & L. reuteri influence pancreatic cancer and the underlying mechanisms.MethodsPancreatic cancer cells were treated with L. casei & L. reuteri and co-cultured with macrophages in a transwell system in vitro. Pancreatic cancer xenograft model was established and L. casei & L. reuteri was used to treat mice in vivo. MTT, CCK-8 assay or immunohistochemical staining were used to determine the proliferation of pancreatic cancer cells or tumor tissues. Transwell assay was applied to test the migration and invasion of pancreatic cells. RT-qPCR was utilized to assess TLR4 and MyD88 expressions in pancreatic cells or tumor tissues. WB, immunofluorescence staining, or flow cytometry was used to evaluate the M1/M2 polarization of macrophages. Besides, the composition of gut microbiota of tumor-bearing mice was determined by 16 S rRNA sequencing, and ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS) untargeted metabolomics was used to evaluate the metabolic profiles of feces.ResultsL. casei & L. reuteri inhibited the proliferation, migration, invasion of pancreatic cancer cells and pancreatic cancer cell-induced M2 polarization of macrophages by suppressing TLR4. Meanwhile, L. casei & L. reuteri repressed pancreatic cancer growth and promoted M1 macrophage polarization. Besides, L. casei & L. reuteri reduced fecal Alloprevotella and increased fecal azelate and glutamate in nude mice, while TLR4 inhibitor TAK-242 increased Clostridia UCG-014, azelate, uridine, methionine sulfoxide, oxypurinol, and decreased glyceryl monoester in the feces of pancreatic tumor-bearing mice. Fecal oxypurinol and glyceryl monoester levels were positively or negatively associated with gut Clostridia UCG-014 abundance, respectively.ConclusionL. casei & L. reuteri alleviate pancreatic cancer by inhibiting TLR4 to promote macrophage M1 polarization and regulate gut microbial homeostasis.