Patient-Derived Cancer Models Research Articles

107 (PB097) - Preclinical characterization of TOS-358, a potent and selective covalent inhibitor of wild-type and mutant PI3Kα with superior anticancer activity

Phosphoinositide 3-kinase alpha (PI3Kα) is the most frequently mutated oncogene in cancer, inferring a critical role for this protein in neoplasia. The molecular biology of PI3Kα reveals it to be a protein that integrates a large and diverse set of cellular signals. In the development of small molecule inhibitors of this target protein it has been demonstrated that deep but also durable inhibition is critical to potent anti-cancer activity, an area traditionally challenging for reversible competitive and allosteric inhibitors. TOS-358 was developed to inhibit covalently both wild-type and mutant PI3Kα with observed IC50 s of 2.2 nM for WT PI3Kα and 4.1 nM for mutant PI3Ka (H1047R). TOS-358 is highly selective in a kinome-wide screen and selective for PI3Kα over other isoforms. We confirmed covalent binding to PI3Kα by NanoBRET in washout experiments, where it was observed that TOS-358 maintained 90% binding at 100 nM 6 hours after washout; in contrast, binding of Alpelisib at 100 nM was completely lost over the same time frame. Irreversible binding was further established using TR-FRET assay in which Kinact/KI was found to be 5.6 × 107 M−1s−1. Importantly, we also noted that TOS-358 produced sustained inhibition of phosphorylated AKT(S473) to 48 hours while allosteric inhibitors lose >60% inhibition. TOS-358 mediated cell growth inhibition has been evaluated in a panel of 120 cell lines and compared with Alpelisib in the same panel. This analysis revealed approximately 50% more cell lines to be responsive to TOS-358 compared with Alpelisib. There was no strong association of response and PI3Kα mutation status, and in fact for both TOS-358 and Alpelisib there was a higher frequency of WT PI3Kα cell lines responding to either treatment. TOS-358 activity has been tested in multiple different cell-derived and patient-derived xenograft cancer models and was found to produce reproducible and substantial tumor growth inhibition. Indeed, in several PDX models, TOS-358 induced tumor regressions while the clinical stage molecules Alpelisib and Inavolisib were unable to generate similar tumor regressions despite pharmacokinetic exposures comparable to, or in excess of, TOS-358. Finally, TOS-358 generated little or no glucose impact in mice and dogs at exposures that produced superior efficacy in these cancer models. Taken together, our in vitro and in vivo data reveal TOS-358 to be a potent, selective covalent inhibitor of PI3Kα with superior anticancer activity to comparator molecules. Conflict of interest: Ownership: The authors are employees of and may hold equity in Totus Medicines.

Multiple-low-dose therapy: effective killing of high-grade serous ovarian cancer cells with ATR and CHK1 inhibitors.

High-grade serous ovarian cancer (HGSOC) is an aggressive disease that typically develops drug resistance, thus novel biomarker-driven strategies are required. Targeted therapy focuses on synthetic lethality-pioneered by PARP inhibition of BRCA1/2-mutant disease. Subsequently, targeting the DNA replication stress response (RSR) is of clinical interest. However, further mechanistic insight is required for biomarker discovery, requiring sensitive models that closely recapitulate HGSOC. We describe an optimized proliferation assay that we use to screen 16 patient-derived ovarian cancer models (OCMs) for response to RSR inhibitors (CHK1i, WEE1i, ATRi, PARGi). Despite genomic heterogeneity characteristic of HGSOC, measurement of OCM proliferation was reproducible and reflected intrinsic tumour-cell properties. Surprisingly, RSR targeting drugs were not interchangeable, as sensitivity to the four inhibitors was not correlated. Therefore, to overcome RSR redundancy, we screened the OCMs with all two-, three- and four-drug combinations in a multiple-low-dose strategy. We found that low-dose CHK1i-ATRi had a potent anti-proliferative effect on 15 of the 16 OCMs, and was synergistic with potential to minimise treatment resistance and toxicity. Low-dose ATRi-CHK1i induced replication catastrophe followed by mitotic exit and post-mitotic arrest or death. Therefore, this study demonstrates the potential of the living biobank of OCMs as a drug discovery platform for HGSOC.

Establishment and genetically characterization of patient-derived xenograft models of cervical cancer

PurposePatient-derived xenograft (PDX) models were established to reproduce the clinical situation of original cancers and have increasingly been applied to preclinical cancer research. Our study was designed to establish and genetically characterize cervical cancer PDX models.MethodsA total of 91 fresh fragments obtained from 22 surgically resected cervical cancer tissues were subcutaneously engrafted into female NOD-SCID mice. Hematoxylin and eosin (H&E) staining was performed to assess whether the established PDX models conserved the histological features of original patient cervical cancer tissues. Moreover, a Venn diagram was applied to display the overlap of all mutations detected in whole-genome sequencing (WGS) data from patient original cervical cancer (F0) and F2-, F3-PDX models. The whole exome sequencing (WES) and the “maftools” package were applied to determine the somatic mutations among primary cervical cancers and the established PDX models.ResultsOur study successfully developed a panel of cervical cancer PDX models and the latency time of cervical cancer PDX model establishment was variable with a progressive decrease as the passage number increased, with a mean time to initial growth of 94.71 days in F1 engraftment to 40.65 days in F3 engraftment. Moreover, the cervical cancer PDX models preserved the histological features of their original cervical cancer. WGS revealed that the genome of original cervical cancer was preserved with high fidelity in cervical cancer PDX models throughout the xenografting and passaging process. Furthermore, WES demonstrated that the cervical cancer PDX models maintained the majority somatic mutations of original cervical cancer, of which the KMT2D, LRP1B, NAV3, TP53, FAT1, MKI67 and PKHD1L1 genes were identified as the most frequently mutated genes.ConclusionsThe cervical cancer PDX models preserved the histologic and genetic characteristics of their original cervical cancer, which helped to gain a deeper insight into the genetic alterations and lay a foundation for further investigation of the molecular targeted therapy of cervical cancer.

Heterogeneity, inherent and acquired drug resistance in patient-derived organoid models of primary liver cancer.

We aimed to elucidate the applicability of tumor organoids for inherent drug resistance of primary liver cancer (PLC) and mechanisms of acquired drug resistance. PLC tissues were used to establish organoids, organoid-derived xenograft (ODX) and patient-derived xenograft (PDX) models. Acquired drug resistance was induced in hepatocellular carcinoma (HCC) organoids. Gene expression profiling was performed by RNA-sequencing. Fifty-two organoids were established from 153 PLC patients. Compared with establishing PDX models, establishing organoids of HCC showed a trend toward a higher success rate (29.0% vs. 23.7%) and took less time (13.0 ± 4.7 vs. 25.1 ± 5.4days, p = 2.28 × 10-13). Larger tumors, vascular invasion, higher serum AFP levels, advanced stages and upregulation of stemness- and proliferation-related genes were significantly associated with the successful establishment of HCC organoids and PDX. Organoids and ODX recapitulated PLC histopathological features, but were enriched in more aggressive cell types. PLC organoids were mostly resistant to lenvatinib in vitro but sensitive to lenvatinib in ODX models. Stemness- and epithelial-mesenchymal transition (EMT)-related gene sets were found to be upregulated, whereas liver development- and liver specific molecule-related gene sets were downregulated in acquired sorafenib-resistant organoids. Targeting the mTOR signaling pathway was effective in treating acquired sorafenib-resistant HCC organoids, possibly via inducing phosphorylated S6 kinase. Genes upregulated in acquired sorafenib-resistant HCC organoids were associated with an unfavorable prognosis. HCC organoids perform better than PDX for drug screening. Acquired sorafenib resistance in organoids promotes HCC aggressiveness via facilitating stemness, retro-differentiation and EMT. Phosphorylated S6 kinase may be predictive for drug resistance in HCC.

Patient-derived cancer models: Valuable platforms for anticancer drug testing.

Molecularly targeted treatments and immunotherapy are cornerstones in oncology, with demonstrated efficacy across different tumor types. Nevertheless, the overwhelming majority metastatic disease is incurable due to the onset of drug resistance. Preclinical models including genetically engineered mouse models, patient-derived xenografts and two- and three-dimensional cell cultures have emerged as a useful resource to study mechanisms of cancer progression and predict efficacy of anticancer drugs. However, variables including tumor heterogeneity and the complexities of the microenvironment can impair the faithfulness of these platforms. Here, we will discuss advantages and limitations of these preclinical models, their applicability for drug testing and in co-clinical trials and potential strategies to increase their reliability in predicting responsiveness to anticancer medications.

Enhanced biological activity of liposomal methylated resveratrol analog 3′-hydroxy-3,4,5,4′-tetramethoxystilbene (DMU-214) in 3D patient-derived ovarian cancer model

3′-hydroxy-3,4,5,4′-tetramethoxystilbene (DMU-214) belongs to methoxystilbenes family and is an active metabolite of 3,4,5,4′-tetramethoxystilbene (DMU-212). In several of our previous studies, the anti-apoptotic activity of DMU-214 was significantly higher than that of the parent compound, especially in ovarian cancer cells. Due to increased lipophilicity and limited solubility, methoxystilbenes require a solubilization strategy enabling DMU-214 administration to the aqueous environment. In this study, DMU-214-loaded liposomes were developed for the first time, and its antitumor activity was tested in the ovarian cancer model. First, several liposomal formulations of DMU-214 were obtained by the thin lipid film hydration method followed by extrusion and then characterized. The diameter of the resulting vesicles was in the range of 118.0-155.5 nm, and samples presented monodisperse size distribution. The release of DMU-214 from the studied liposomes was governed by the contribution of two mechanisms, Fickian diffusion and liposome relaxation. Subsequently, in vitro activity of DMU-214 in the form of a free compound or liposome-bound was studied, including commercial cell line SK-OV-3 and patient-derived ovarian cancer cells in monolayer and spheroid cell culture models. DMU-214 liposomal formulations were found to be more potent (had lower IC50 values) than the free DMU-214 both in the monolayer and, more significantly, in both examined spheroid models. The above results, with particular emphasis on the patient-derived ovarian cancer model, indicate the importance of further development of liposomal DMU-214 as a potential anticancer formulation for ovarian cancer treatment.

Highlights from Recent Cancer Literature

Highlights from Recent Cancer Literature

Combination of T-DM1 and platinum-based chemotherapy in patient-derived xenograft models of muscle-invasive bladder cancer.

Objective(s):To assess the efficacy and safety of T-DM1, as an anti-HER2 antibody-drug conjugate (ADC), alone and in combination with two platinum-based chemotherapy regimens in patient-derived xenografts (PDXs) of muscle-invasive bladder cancer (MIBC) established in immunodeficient mice. Materials and Methods:After treatment initiation, tumor size was measured twice a week. Percent of tumor growth inhibition (TGI) and tumor response rates were calculated as efficacy endpoints. To evaluate treatment toxicity, relative body weight (RBW) was calculated for each group. For comparison of TGIs between treatment groups, the Kruskal-Wallis test was used. Also, the significance of the overall response (OR) rate between placebo groups with treatment groups was analyzed using Fisher’s exact test. Immunohistochemistry and fluorescence in situ hybridization techniques were used to evaluate the level of HER2 expression.Results:Our data showed that T-DM1 alone induced a moderate antitumor activity. While chemotherapy regimens induced a slight TGI when administered alone, interestingly, they showed strong antitumor activity when administered combined with T-DM1. The OR rates were higher when T-DM1 was combined with chemotherapy regimens than T-DM1 alone. When compared with the placebo group, the OR rates of combination groups were statistically significant. Our data also showed that the administered dose of each drug was well tolerated in mice. Conclusion:The combination of T-DM1 and platinum-based chemotherapy may represent a new treatment option for bladder tumors with even low HER2 expression, and could also provide substantial novel insight into tackling the challenges of MIBC management.

Abstract 3085: Establishment and characterization of two novel patient-derived organoid xenograft models of advanced prostate cancer

Abstract Introduction: An important clinical need remains to improve survival of men with advanced metastatic prostate cancer (PCa). A better understanding of the mechanisms underlying PCa progression and treatment resistance is a prerequisite to address this challenge, which is currently limited by the scarcity of experimental models. Here, we aimed at establishing and characterizing new patient-derived organoids xenograft (PDOX) models of advanced PCa. Materials & methods: We used two patient-derived organoid lines (PDOs), previously generated in our laboratory. P20-11 PDOs were derived from a lung metastasis obtained from a patient with hormone-naïve PCa. P20-23 PDOs were derived from a transurethral prostate resection obtained from a patient with metastatic castration-resistant PCa, previously treated with goserelin, docetaxel, and enzalutamide. PDOX were generated by subcutaneous injection of PDOs in NOD scid gamma (NSG) male mice. Organoids were derived from the PDOX tumors (PDOX-O). Matched patients’ tumor, PDOs, PDOX and PDOX-O samples were characterized using immunohistochemistry (IHC), immunofluorescence (IF), and whole exome sequencing (WES). Organoids were treated with different concentrations of drugs and cell viability was measured using CellTiter-Glo 3D, after a 5-day long treatment. Results: P20-11 PDOs developed tumors in 2 out of 6 mice, 10 months after injection. IHC analysis highlighted a loss of PTEN expression, overexpression of ERG and P53, as well as strong AR and NKX3.1 expression in the tumor, PDOs, PDOX and PDOX-O samples. WES analysis uncovered mutations in CTNNB1, PTEN and TP53 in all samples, and approximately 87% of shared non-synonymous mutations between the PDOX and the original patients’ tumor. Similar to the original PDOs, P20-11 PDOX-O displayed androgen sensitivity in vitro. P20-23 PDOs formed tumors in 3 out of 3 mice 8 months following injection. IHC and IF analyses highlighted a strong expression of CK8, PSMA, AR and NKX3.1, as well as a loss of PTEN expression in the tumor, PDOs, PDOX and PDOX-O samples. WES identified a pathogenic mutation in the PCa-associated gene ZMYM3 in all samples, associated with loss of protein expression. The activating AR point mutation L702H, previously linked to AR signaling inhibitors resistance, was detected in the tumor and in 2 out of 3 PDOX and their derived organoids. Overall, an average of 80% of non-synonymous mutations were shared between the patients’ tumor and PDOX. Finally, P20-23 PDOX-O did not respond to docetaxel or enzalutamide but exhibited sensitivity to the PI3K/AKT inhibitor ipatasertib. Conclusion: We have successfully generated two novel PDOX models, which highly resemble the original patients’ tumor and can be further cultured as organoids. These models are representative of relevant clinical and molecular subtypes of advanced PCa, providing further opportunities for translational studies. Citation Format: Raphaëlle Servant, Zoi Diamantopoulou, Michele Garioni, Luca Roma, Tatjana Vlajnic, Arnoud J. Templeton, Heike Pueschel, Salvatore Piscuoglio, Nicola Aceto, Helge Seifert, Cyrill A. Rentsch, Bubendorf Lukas, Clémentine Le Magnen. Establishment and characterization of two novel patient-derived organoid xenograft models of advanced prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3085.

Abstract 3494: Characterizing the relationship between genotype and phenotype in DNA damage response-altered pancreatic cancer models

Abstract Alterations in DNA damage response (DDR) proteins are prevalent across cancers and present unique opportunities for the therapeutic induction of synthetic lethality (i.e., two gene deficiencies in the same pathway synergize to kill tumor cells). In pancreatic adenocarcinoma, patients harboring alterations in DDR genes, such as in homology-directed repair (HDR), comprise the 10-20% of patients that may benefit from the recent FDA approval of Olaparib, a poly (ADP-ribose) polymerase inhibitor that disrupts non-homologous end joining (NHEJ). Despite being the best-in-class targeted therapy for DDR-altered pancreatic cancers, a subset of patients fails to respond to Olaparib and those that initially respond eventually go on to develop resistance. The mechanisms underlying resistance are poorly elucidated but suggest that some patients harboring DDR-altered tumors are HDR-proficient or revert to HDR-proficiency during therapy, bypassing the second gene deficiency requisite for synthetic lethal induction with targeted therapy (e.g., Olaparib). Utilizing patient-derived models of cancer, we are actively investigating DDR-altered, pancreatic tumor cell lines and exploring the relationship between DDR-alterations and HDR-deficiency with three goals: [1] To evaluate the prevalence of HDR-proficiency in BRCA-altered tumors, [2] to understand the extent to which patient-derived models of cancer are concordant and predictive of clinical outcomes, and [3] to identify novel therapeutic strategies for resistant patients. So far, we have observed HDR-proficiency by functional assays (e.g., RAD51 foci formation) in DDR-altered patient-derived cell lines that corresponds with poor response to Olaparib in vitro, and resistance to platinum therapy clinically. Whereas DDR-altered HDR-deficient lines had greater sensitivity to Olaparib and platinum therapy. These early data suggest that measures of HDR by functional assay may be more predictive of clinical therapeutic responses than the use of genetic signatures alone. Citation Format: James R. Carroll, Jason M. Link, Jonathan R. Brody. Characterizing the relationship between genotype and phenotype in DNA damage response-altered pancreatic cancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3494.

Abstract 3115: Establishment and characterization of patient-derived breast cancer models for cancer studies

Abstract BACKGROUND: Despite the progress and development of targeted agents and Immunotherapeutics, breast cancer is still the leading cause of death among women worldwide. At present, targeted therapy for breast cancers include endocrine blockage therapy for estrogen receptor positive (ER+) tumors and trastuzumab or lapatinib for HER2 positive (HER2+) tumors and CDK inhibitors for HER negative (HER-) tumors as well as PARP inhibitors for BRCA1/2 mutations. There is still a high unmet need for triple negative breast cancer (TNBC) and relapsed breast cancers with specific mutations. Breast cancer is a highly heterogeneous disease and reliable breast cancer models are needed to develop new clinical therapies and better reflect tumor biology. Patient-derived xenograft (PDX) models have been widely used for understanding tumor characteristics and represent human heterogeneity more faithfully and thus are suitable for mouse clinical studies for predicting drug efficacy in the clinic. Here we report the establishment and characterization of a panel of breast cancer (BC) PDX for preclinical research. METHODS: Tumor samples from patients’ breast tumor or metastastic lesion obtained via surgery, biopsy, or pleural effusions/ascites were engrafted subcutaneously in immunodeficient mice to establish PDX models. The models were classified and characterized by histopathology, immunohistochemistry (IHC), and breast cancer specific biomarkers such as estrogen receptor (ER), progesterone receptor (PR) and HER2. Genomic analysis of these models was performed by next generation sequencing (NGS). In these breast cancer models, the effects of estrogen on tumor growth and targeted endocrine therapy such as Fulvestrant were evaluated. The change of tumor volume over time was used to determine the growth rate and response to treatment in mice. RESULTS: A series of BC PDX models derived from primary patient breast tumor or metastatic lesions were successfully established and characterized. Key characteristics of parental tumors, such as histopathology, clinical markers, gene expression and copy number, as well as estrogen dependence was retained. The IHC data indicated various expression levels of ER, PR and HER2 across the panel, with TNBC being the dominant subtype. ESR1 mutation, which may play an important role in BC progression and endocrine therapy resistance, was also identified in an estrogen-independent model. In vivo, these models showed distinct tumor growth rates and different pharmacodynamic responses to standard of care agents. For example, ESR1 mutant model was responsive to Fulvestrant. CONCLUSIONS: The established BC PDX panel represent a range or ER/PR/HER2 expression status from primary and advanced cancer providing a series of preclinical models for breast cancer research and potential for mouse clinical trial enrollment. Citation Format: Leilei Chen, Xueying Yang, Likun Zhang, Xiaobo Chen, Henry Q.X. Li, Jingjing Wang. Establishment and characterization of patient-derived breast cancer models for cancer studies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3115.

Abstract 180: Automation and high content imaging of 3D triple negative breast cancer patient-derived tumoroids assay for compound screening

Abstract Introduction: Currently there are no clinically approved small molecule targeted therapies for triple negative breast cancer, underlining the critical need to discover new therapeutic targets. Patient-derived cell-based 3D cancer models are highly valuable tools for cancer research and drug development. Primary tumor-derived models can recapitulate tumor heterogeneity and morphology, as well as complex genetic and molecular composition accelerating drug development and drug testing. However, the complexity of performing 3D assays remains a hurdle for adopting these methods for compound screening. In the present study we describe automation of imaging and cell culture methods that enables scaling up complex 3D cell-based assays and compound screening. Methods: We developed an integrated workcell that includes a confocal imaging system, an automated CO2 incubator, an automated liquid handler, and a Collaborative Robot combining different instruments. Workcell allows automation of compound testing, culture monitoring, and evaluation of phenotypic effects of drugs with high content imaging. Tumoroids were formed from primary cells isolated from a patient-derived tumor explant, TU-BcX-4IC, that represents metaplastic breast cancer with a triple-negative breast cancer subtype. Cells were expanded in 2D format, then tumoroids were formed by plating 2,000 cells per well in U-shape low attachment 384 plates. Tumoroids (200 μm in diameter) were formed 48 hr after plating and were treated with 165 compounds of approved cancer drugs from the NCI library at multiple concentrations (10 nM to 100 μM). Compound dilutions, additions, media additions, and staining were performed using liquid handler. During incubation with compounds, tumoroids were monitored daily using transmitted light imaging. For end point assay tumoroids were stained with viability dyes and imaged using automated confocal imaging system. Advanced image analysis included 3D reconstitution and complex phenotypic evaluation of tumoroids. Results: We characterized multiple quantitative descriptors that can be used for studying tumor phenotypes and compound effects including characterization of size and integrity, cell morphology and viability, as well as determining presence and expression levels for various cell markers. Concentration-dependent effects of numerous compounds were observed across multiple read-outs that indicate cytotoxic effects, with 8 compounds demonstrating effects at 10 nM (e.g, romidepsin, trametinib, bortezomib, carfilzomib, and panobinostat). These compounds include HDAC inhibitors and proteosome inhibitors. Conclusions: We demonstrated methods for increased throughput and automation in 3D cancer assays and compound screening, and also analysis approaches and descriptors that provide information about cell phenotypes and compound effects. Citation Format: Oksana Sirenko, Angeline Lim, Courtney K. Brock, Katya Nikolov, Cathy Olsen, Evan F. Cromwell, Margarite D. Matossian, Matthew E. Burow. Automation and high content imaging of 3D triple negative breast cancer patient-derived tumoroids assay for compound screening [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 180.

Abstract 1753: IKS014, a HER2-targeting antibody drug conjugate incorporating novel bioconjugation and tumor-selective linker technology with improved in vivo efficacy and tolerability

Abstract HER2 has long been a target of high interest for antibody and antibody drug conjugate (ADC) therapeutics due to its well-documented overexpression in breast, gastric and lung cancer. While trastuzumab and ado-trastuzumab emtansine (T-DM1) have become an integral part of treatment paradigms for HER2-positive cancer, the more recent approvals of the fam-trastuzumab deruxtecan (DS-8201) ADC and the Fc-engineered margetuximab antibody have highlighted the potential for continued improvement over existing HER2-targeting therapies. IKS014 is a HER2-directed ADC that incorporates site-directed conjugation and tumor-selective glucuronide-trigger linker technology to reduce systemic off-target toxicity while maximizing efficient intracellular lysosomal payload release, thus holding the promise of a wider therapeutic index. IKS014 was generated by site-specific conjugation via a proprietary beta-glucuronide linker to the microtubule agent MMAF with a drug-to-antibody ratio (DAR) 2. In vitro and in vivo activity was evaluated in HER2-positive preclinical models with varying HER2 expression levels in comparison to benchmark ADCs. Pharmacokinetics (PK) and tolerability studies were conducted in rodent and cynomolgus monkey. IKS014 conjugation resulted in a homogeneous ADC with defined DAR and good physio-chemical properties. In vitro, IKS014 demonstrated dose dependent specific cytotoxicity against Her2-positive cell lines. In JIMT-1 breast cancer xenografts with moderate HER2-expression (HER2 IHC 2+), IKS014 causes complete regressions at a single dose of 5 mg/kg and partial regressions at 1 mg/kg, while T-DM1 results in only tumor growth inhibition even at 15 mg/kg. Anti-tumor efficacy of IKS014 in NCI-N87 (HER2 3+) gastric xenografts is comparable to DS-8201 but superior to T-DM1 at equivalent single doses ranging from 1 to 5 mg/kg. In a HER2-positive patient-derived gastric cancer model (HER2 2+), IKS014 was highly active at 5mg/kg Q2W x2, while T-DM1 was inactive at the same dosing schedule. IKS014 demonstrated stable PK with a terminal half-life of 8.7 days in rat and 4.6 days in monkey, and DAR 2 was maintained for up to 4 weeks. In cynomolgus monkeys, IKS014 was tolerated at 12 mg/kg single dose and 5 mg/kg repeat dose without ocular or lung toxicity findings. IKS014 was highly efficacious against HER2-positive tumor xenografts in vivo, including models with moderate target expression, and compared favorably to clinically validated benchmark ADCs. This improved preclinical efficacy combined with stable PK and good tolerability profile warrants further development of this novel ADC for HER2-positive cancers. Citation Format: Jutta Deckert, Jenny Thirlway, Yun-Hee Park, Ho Young Song, Chul-Woong Chung, Xuesong Wang, Zhenshan Zhang, Robert J. Lutz. IKS014, a HER2-targeting antibody drug conjugate incorporating novel bioconjugation and tumor-selective linker technology with improved in vivo efficacy and tolerability [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1753.

Abstract 1190: MMHCdb: A knowledgebase for the evolving landscape of mouse models of human cancer

Abstract The laboratory mouse is the premier mammalian model organism for interrogating the genetic and molecular basis of human cancer and for preclinical investigations into targets for the prevention and treatment of cancer. The distributed and heterogenous nature of information about these model systems makes it difficult for researchers to integrate and interpret the information to determine the state of the field and to identify the most relevant models for basic and preclinical research. The Mouse Models of Human Cancer database (http://tumor.informatics.jax.org) is an expertly curated knowledgebase about genetically defined mouse strains and Patient Derived Xenograft (PDX) models of human cancer. Data in MMHCdb are obtained from peer-reviewed scientific publications and direct data submissions from individual investigators and large-scale programs. MMHCdb is built on FAIR data management principles (Findable, Accessible, Interoperable, Reusable). The enforcement of metadata standards and official gene, allele and strain nomenclature ensure accurate and comprehensive search results for cancer models. MMHCdb has long represented data from spontaneous or endogenously induced tumors from genetically defined mice and for PDXs which have been the foundation of basic cancer research and preclinical studies for decades. MMHCdb has expanded to include cancer models such as Diversity Outbred and Collaborative Cross mice which are ideally suited for research into the relationship of genetic variation with cancer susceptibility and for modeling the genetics of variability in treatment responses. The MMHCdb contains over 109,266 curated tumor frequency records for over 8,275 mouse strains. Tumor types in the database have been indexed to over 21,000 literature citations. PDX models and data available in MMHCdb are also accessible from the Patient Derived Cancer Models resource at EMBL-EBI which currently provides information for over 4,000 PDXs (https://cancermodels.org).MMHCdb is supported by NCI R01 CA089713 Citation Format: Dale A. Begley, Debbie M. Krupke, Steven Neuhauser, John Sundberg, Carol J. Bult. MMHCdb: A knowledgebase for the evolving landscape of mouse models of human cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1190.

Abstract 3105: PDCM Finder: An open global cancer research platform for patient-derived cancer models

Abstract PDCM Finder (https://cancermodels.org) is a new portal that aggregates patient-derived models (xenografts, cell lines and organoids) from 27 academic and commercial providers, enables users to search and compare over 6000 models and associated molecular data, and connects users with model providers to facilitate collaboration among researchers. Users can search for models of interest by either (1) exploring molecular data summaries for models of specific cancer types, or (2) using the intuitive search and faceted filtering options of the web user interface or (3) access resource database via REST API to run their own analysis. The data includes gene expression, gene mutation, copy number alteration, cytogenetics, patient treatment and drug dosing studies. We link external resources like publication platforms and cancer specific annotation tools enabling exploration and prioritization of PDCM variation data (COSMIC, CIViC, OncoMX, OpenCRAVAT). In addition to exploring PDCM metadata and data, the portal enables users to validate their PDX models against PDX MI standard, get a FAIRness score of the model of interest, explore originating resource data processing protocols, training materials and contact the model supplier/provider. PDCM Finder builds on the success of the PDX Finder resource (PMID:30535239). Critical PDCM attributes, such as diagnosis, drug names and genes, are harmonized and integrated into a cohesive ontological model based on the PDX Minimal information standard (PDX MI, PMID: 29092942). PDX MI has become established in the community for data exchange, adopted by the PDX providers, consortia and informatics tools integrating PDX data. We are working with the community on the PDCM Minimal Information standard in an effort to make PDCM datasets adhere to the FAIR data principles. We are driving the development of and promoting the use of descriptive standards to facilitate data interoperability and promote global sharing of models. We provide expertise and software components to support several worldwide consortia including PDXNet, PDMR and EurOPDX. PDCM Finder is freely available under an Apache 2.0 license (https://github.com/PDCMFinder). This work is supported by NCI U24 CA204781 01, U24 CA253539, and R01 CA089713. We welcome feedback on the resource and are looking for participants for usability studies - please get in touch if interested. Citation Format: Zinaida Perova, Csaba Halmagyi, Alex Follette, Mauricio Martinez, Federico Lopez-Gomez, Jeremy Mason, Abayomi Mosaku, Nathalie Conte, Ross Thorne, Steven Neuhauser, Dale Begley, Debra Krupke, Terrence Meehan, Carol Bult, Helen Parkinson. PDCM Finder: An open global cancer research platform for patient-derived cancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3105.

Abplatin(IV) inhibited tumor growth on a patient derived cancer model of hepatocellular carcinoma and its comparative multi-omics study with cisplatin

BackgroundCisplatin, the alkylating agent of platinum(II) (Pt(II)), is the most common antitumor drug in clinic; however, it has many side effects, therefore it is higly desired to develop low toxicity platinum(IV) (Pt(IV)) drugs. Multi-omics analysis, as a powerful tool, has been frequently employed for the mechanism study of a certain therapy at the molecular level, which might be helpful for elucidating the mechanism of platinum drugs and facilitating their clinical application.MethodsStrating form cisplatin, a hydrophobic Pt(IV) prodrug (CisPt(IV)) with two hydrophobic aliphatic chains was synthesized, and further encapsulated with a drug carrier, human serum albumin (HSA), to form nanoparticles, namely AbPlatin(IV). The anticancer effect of AbPlatin(IV) was investigated in vitro and in vivo. Moreover, transcriptomics, metabolomics and lipidomics were performed to explore the mechanism of AbPlatin(IV).ResultsCompared with cisplatin, Abplatin(IV) exhibited better tumor-targeting effect and greater tumor inhibition rate. Lipidomics study showed that Abplatin(IV) might induce the changes of BEL-7404 cell membrane, and cause the disorder of glycerophospholipids and sphingolipids. In addition, transcriptomics and metabolomics study showed that Abplatin(IV) significantly disturbed the purine metabolism pathway.ConclusionsThis research highlighted the development of Abplatin(IV) and the use of multi-omics for the mechanism elucidation of prodrug, which is the key to the clinical translation of prodrug.Graphical

Phase 1 study of SGN-B7H4V, a novel, investigational vedotin antibody–drug conjugate directed to B7-H4, in patients with advanced solid tumors (SGNB7H4V-001, trial in progress).

TPS3155 Background: B7-H4, a B7 immune checkpoint ligand, is expressed at low levels in normal tissue and negatively regulates T-cell function by inhibiting T-cell proliferation and cytokine production. B7-H4 expression is elevated in solid tumors, including breast, ovarian, and endometrial cancers. Targeting B7-H4–expressing tumor cells may relieve B7-H4–mediated T-cell inhibition. SGN-B7H4V is a novel, investigational vedotin antibody–drug conjugate directed to B7-H4 with proposed mechanisms of action including monomethyl auristatin E (MMAE)-directed cytotoxicity, bystander effect, antibody-dependent cellular cytotoxicity, and antibody-dependent cellular phagocytosis. SGN-B7H4V elicited antitumor activity in cell line-derived xenograft models of triple-negative breast cancer (TNBC) and patient-derived xenograft models of TNBC and ovarian cancer (Gray et al 2021), providing a rationale to evaluate SGN-B7H4V in patients (pts) with advanced solid tumors. Methods: SGNB7H4V-001 (NCT05194072) is a phase 1, first-in-human, multicenter, open-label trial evaluating the safety, tolerability, pharmacokinetics (PK), and antitumor activity of SGN-B7H4V in pts with advanced solid tumors. This study includes 3 parts: dose escalation (Part A), dose and schedule optimization (Part B), and dose expansion in disease-specific cohorts and a biology cohort (Part C). Adult pts (≥18 years) with histologically/cytologically confirmed locally advanced unresectable or metastatic solid tumors including high-grade serous epithelial ovarian cancer, primary peritoneal cancer, fallopian tube cancer, human epidermal growth factor receptor 2-negative and hormone receptor-positive breast cancer, TNBC, endometrial carcinoma, squamous non-small cell lung cancer, cholangiocarcinoma, or gallbladder carcinoma, are eligible. Pts must have ECOG PS 0–1 and relapsed/refractory disease or be intolerant to standard-of-care therapies. Prior treatment with an MMAE-containing agent or a B7-H4–targeted agent is not permitted. Primary endpoints include the rate of adverse events, laboratory abnormalities, dose-limiting toxicities, and cumulative dose-level safety. Secondary endpoints are objective response rate (ORR), complete response rate, duration of objective response (DOR), progression-free survival (PFS), overall survival (OS), PK, and incidence of antidrug antibodies. Exploratory endpoints include pharmacodynamic (PD) analyses, PD and PK exposure measurements, B7-H4 characterization on malignant cells, and biomarker analyses. Safety and antitumor activity endpoints will be assessed using descriptive statistics. ORR will be analyzed by tumor type and dose. DOR, PFS, and OS will be estimated using the Kaplan–Meier method. Enrollment for Part A is ongoing in North America and is planned in Europe. Clinical trial information: NCT05194072.

A2B adenosine receptor antagonists rescue lymphocyte activity in adenosine-producing patient-derived cancer models

BackgroundAdenosine is a metabolite that suppresses antitumor immune response of T and NK cells via extracellular binding to the two subtypes of adenosine-2 receptors, A2ARs. While blockade of the A2AARs...

Progenitor cells derived from gene-engineered human induced pluripotent stem cells as synthetic cancer cell alternatives for in vitro pharmacology.

Limitations in genetic stability and recapitulating accurate physiological disease properties challenge the utility of patient-derived (PD) cancer models for reproducible and translational research. A portfolio of isogenic human induced pluripotent stem cells (hiPSCs) with different pan-cancer relevant oncoprotein signatures followed by differentiation into lineage-committed progenitor cells was genetically engineered. Characterization on molecular and biological level validated successful stable genetic alterations in pluripotency state as well as upon differentiation to prove the functionality of our approach. Meanwhile proposing core molecular networks possibly involved in early dysregulation of stem cell homeostasis, the application of our cell systems in comparative substance testing indicates the potential for cancer research such as identification of augmented therapy resistance of stem cells in response to activation of distinct oncogenic signatures.

Establishment and characterization of NCC-DDLPS5-C1: a novel patient-derived cell line of dedifferentiated liposarcoma.

Dedifferentiated liposarcoma (DDLPS) is a highly aggressive subtype of liposarcoma that is morphologically defined as a transition from a well-differentiated lipomatous component to a non-lipogenic one. Curative therapy for DDLPS is complete resection, and the benefits of current systemic chemotherapy remain marginal. Although DDLPS is molecularly characterized by co-amplification of MDM2 and CDK4 (12q14-15) and detailed genomic analyses have been conducted by multiple research groups, the effects of molecular targeted drugs are marginal, and novel therapeutic modalities are required. Although patient-derived cell lines are pivotal for cancer research, no DDLPS cell lines are currently available from public cell repositories. Accordingly, in this study, we established a novel DDLPS cell line, NCC-DDLPS5-C1, using surgically resected tumor tissues from a patient with DDLPS. NCC-DDLPS5-C1 cells exhibited typical gene amplification, overexpression of MDM2 and CDK4, and other DNA copy number alterations. The NCC-DDLPS5-C1 cells were capable of rapid cell proliferation, aggressive invasion, and spheroid formation, but not tumor formation in mice. We reported the utility of NCC-DDLPS5-C1 cells for a drug-response assay to detect anticancer drugs that significantly attenuated cell proliferation. Thus, we concluded that the NCC-DDLPS5-C1 cell line could be a useful resource for the study of DDLPS. Considering the diversity of disease in terms of clinical outcomes, continuous efforts are required to develop more patient-derived cancer models with different clinical and pathological backgrounds.