Standard Of Care Drugs Research Articles

Patient-derived acellular ascites fluid affects drug responses in ovarian cancer cell lines through the activation of key signalling pathways.

Malignant ascites is commonly produced in advanced epithelial ovarian cancer (EOC) and serves as unique microenvironment for tumour cells. Acellular ascites fluid (AAF) is rich in signalling molecules and has been proposed to play a role in the induction of chemoresistance. Through in vitro testing of drug sensitivity and by assessing intracellular phosphorylation status in response to mono- and combination treatment of five EOC cell lines after incubation with AAFs derived from 20 different patients, we investigated the chemoresistance-inducing potential of ascites. We show that the addition of AAFs to the culture media of EOC cell lines has the potential to induce resistance to standard-of-care drugs (SCDs). We also show that AAFs induce time- and concentration-dependent activation of downstream signalling to signal transducer and activator of transcription 3 (STAT3), and concomitantly altered phosphorylation of mitogen-activated protein kinase kinase (MEK), phosphoinositide 3-kinase (PI3K)-protein kinase B (AKT) and nuclear factor NF-kappa-B (NFκB). Antibodies targeting the interleukin-6 receptor (IL6R) effectively blocked phosphorylation of STAT3 and STAT1. Treatments with SCDs were effective in reducing cell viability in only a third of 30 clinically relevant conditions examined, defined as combinations of drugs, different cell lines and AAFs. Combinations of SCDs and novel therapeutics such as trametinib, fludarabine or rapamycin were superior in another third. Notably, we could nominate effective treatment combinations in almost all conditions except in 4 out of 30 conditions, in which trametinib or fludarabine showed higher efficacy alone. Taken together, our study underscores the importance of the molecular characterisation of individual patients' AAFs and the impact on treatment resistance as providing clinically meaningful information for future precision treatment approaches in EOC.

Abstract 5957: Development of a selective, oral ATP-competitive CDK9 inhibitor, BLX-3030, for treatment of pancreatic cancer

Abstract Introduction Transcription regulators, such as cyclin-dependent kinase 9 (CDK9), have been implicated in the super-enhancer driven transcriptional control of oncogenes in multiple cancers including pancreatic cancer. CDK9 has been shown to be employed by cancer cells for the constant production of short-lived oncoproteins such as c-Myc to maintain their survival. Due to its critical role in regulating transcription in cancer cells, CDK9 has emerged as a potential therapeutic target. Here, we report the antitumor activity of a selective, oral ATP-competitive CDK9 inhibitor, BLX-3030, in preclinical models for pancreatic cancer. Experimental Procedures Fragment-based MolecuLern driven AI workflow methods were used to design a series of ATP-competitive CDK9 specific kinase inhibitors. BLX-3030 was selected as one of the most potent leads with an IC50 of 1.1 nM in a cell-free CDK9 kinase assay. A Sulforhodamine B (SRB) assay was used to evaluate the cell growth inhibitory activity of BLX-3030 in a panel of 10 pancreatic ductal adenocarcinoma (PDAC) and 2 pancreatic neuroendocrine tumor (pNET) cell lines. Western blotting was used to determine the effects of BLX-3030 treatment on c-Myc expression in cancer cells. The combination effects between BLX-3030 and standard of care regimen, gemcitabine (GEM) and nab-paclitaxel (NP), was assessed using the SRB assay. Finally, the in vivo antitumor activity of BLX-3030 alone or in combination with GEM and NP was evaluated in a mouse cell line xenograft model for pancreatic cancer. Results BLX-3030 exhibited potent cell growth inhibitory activity in the panel of pancreatic cancer cell lines with IC50 values ranging from 133.5 nM to 508.1 nM. The potency of BLX-3030 in the cell lines appears to correlate with the expression level of c-Myc in the cell lines. BLX-3030 showed similar activities in PDAC and pNET cell lines with mean IC50 values of 244.5 nM and 194.6 nM, respectively. However, treatment with BLX-3030 for 48 hours did not seem to significantly reduce c-Myc expression in PSN-1 PDAC cells. When combined with GEM and NP, BLX-3030 demonstrated mostly additive effects in PSN-1 cells. Preliminary data from the in vivo study show that BLX-3030 improves the antitumor activity of GEM and NP. Conclusion In summary, BLX-3030 potently inhibited the growth of both PDAC and pNET cells in vitro. The growth inhibitory activity of BLX-3030 in PDAC cell lines correlates with their c-Myc expression levels. BLX-3030 showed an additive effect when combined with standard of care drugs (GEM and NP) in PDAC cell lines. Overall, the novel CDK9 inhibitor, BLX-3030, demonstrated potent activity in pancreatic cancer cell line models and presents a promising preclinical lead for pancreatic cancer. (This work was supported in part by Biolexis Therapeutics and the Seena Magowitz Foundation). Citation Format: Yesenia Barrera-Millan, Zhaoliang Li, Hariprasad Vankayalapati, David J. Bearss, Daniel D. Von Hoff, Haiyong Han. Development of a selective, oral ATP-competitive CDK9 inhibitor, BLX-3030, for treatment 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 5957.

Abstract 6492: KRAS inhibitor-based combinations in pancreatic cancer identified through Optim.AI

Abstract PURPOSE: KRAS is the most frequently mutated oncogene in almost all cancers, including pancreatic ductal carcinoma (PDAC) and colorectal cancer. Increased development efforts targeting KRAS mutations have yielded recent FDA approvals of two KRAS G12C inhibitors. However, this is beneficial for only a small proportion of patients especially with indications like PDAC, where G12C mutations are rare (1%) while G12D mutations account for approximately 45%. Hence, there is a need to develop methods to target a broader range of KRAS mutations. Beyond direct gene mutation, activation of oncogenic KRAS and downstream or parallel signaling through other genomic alterations may benefit from KRAS-specific therapeutic strategies, especially combination therapy. In this study, Optim.AI™, a hybrid computational-experimental platform is harnessed to identify mutation-specific optimal therapies and to stratify efficacious drug combinations containing KRAS inhibitors in pancreatic cancer. METHODS: Optim.AI™ utilizes small datasets to rationally converge upon optimal drug combinations within a defined drug search space. By mapping experimental data points to a second-order quadratic function, Optim.AI™ predicts cell killing efficacies for all possible combinations, independent of the background of the models utilized. In this study, pancreatic cancer cell lines, with varying KRAS mutations, were tested with an array of 155 different combinations consisting of 12 drugs at varying concentrations. The drugs include KRAS G12C inhibitors, Sotorasib and Adagrasib, KRAS inhibitors in development, and approved therapies used clinically for PDAC. Post-drug treatment viability was measured and used for Optim.AI™ analysis, to rank and compare the top therapies across the different cell lines. RESULTS: Through Optim.AI™ analysis, we observed a range of sensitivities towards KRAS inhibition, even for both Sotorasib and Adagrasib. Compared against HT-29 cell line, harboring wild type KRAS, we have identified distinct combinations of KRAS inhibitors with standard of care drugs on cell lines with G12D, G12V and G12C KRAS mutants. Subsequent validation of the top and bottom ranked combinations for the respective cell lines correspond to the predicted Optim.AI™ results. CONCLUSIONS: This study has demonstrated the differential sensitivities of the KRAS inhibitors across several pancreatic cancer cell lines, with different KRAS mutational profiles. Notably, we have identified KRAS inhibitor-based combinations that are distinctly different from wild type KRAS cell line. These preliminary findings could be used to drive precision medicine by identifying suitable biomarkers to potentially stratify pancreatic cancer patients and improve treatment outcomes. Future work includes evaluating the clinical significance of these combinations by validating them on patient-derived organoids. Citation Format: Jhin Jieh Lim, Edward Kai-Hua Chow, Masturah Rashid. KRAS inhibitor-based combinations in pancreatic cancer identified through Optim.AI [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 6492.

Abstract 4235: PD3D®models as jacks-of-all-trades for cancer research and therapy response prediction

Abstract Physiologically relevant in vitro tumor models are crucial in any research setting from preclinical drug development to functional precision oncology. Patient-derived 3D cell culture models (PD3D®) are validated cancer models which recapitulate the biology of the original tumor tissue. PD3D® can be used to model intratumoral heterogeneity in medium and high throughput screens. Using a reverse clinical engineering approach, PD3D® models are already applied in personalized oncology to identify treatment for an individual patient. We successfully established a living biobank of more than 500 PD3D® models, spanning from common cancers like colorectal, breast (incl. TNBC), non-small cell lung and pancreatic carcinoma, to orphan indications including various subtypes of sarcomas. Not surprisingly, PD3D® model morphology and culture requirements differ between tumor entities. Treating PD3D® models with standard of care drugs in a semi-automated high-throughput assay, we observed heterogeneity in drug sensitivity between models of the same cancer type, recapitulating clinical response of patients. Combining drug sensitivity profiles with genomic and proteomic data of the same PD3D® models, we successfully identified a biomarker for predicting chemosensitivity towards MEK-targeting drugs. For application of PD3D® in truly personalized oncology, we developed a protocol that allows us to generate a PD3D® culture and perform a drug sensitivity assay for an individual patient within a therapy-relevant timeframe. Within 38 days we identified a systemic therapy for a young patient with a relapsed metastasized synovial sarcoma. After surgery and initiation of recommended chemotherapy, the patient is now under remission. To further expand the scope of PD3D® for therapy response prediction, we established a method for irradiation of PD3D® cultures with different dosages of photon and proton radiation. We observed significant, model specific differences in radiosensitivity between PD3D® sarcoma models which also reflect clinically heterogenous responses. Additionally, PD3D® models can be employed for a tumor organoid-on-chip platform (TumOC), delivering real-time information on physiological parameters like drug response-mediated oxygen consumption in a microfluidic system. In conclusion, PD3D® models act as jacks-of-all-trades in current and future cancer research, delivering robust and reliable data that not only is of academic value, but speeds up the drug development process, and are ready for prime time in functional precision oncology. Citation Format: Lena Wedeken, Samantha Forbrig, Katja Herrera-Glomm, Juergen Loskutov, Ulrike Pfohl, Irina Piven, Michael Poehle, Manuela J. Regenbrecht, Barbara Seller, Cynthia Yapto, Sabine Finkler, Larissa Ruhe, Quirin Graf Adelmann, Christoph Reinhard, Marie Flechner, Katja Uhlig, David Kaul, Siyer Roohani, Maya Niethard, Rica Sauer, Christian R. Regenbrecht. PD3D®models as jacks-of-all-trades for cancer research and therapy response prediction [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 4235.

Macropinocytosis As a Means of Selectively Targeting RAS-Mutant Multiple Myeloma

Introduction Roughly, 50% of multiple myeloma (MM) is driven by mutant RAS, both at presentation and more at relapse. Currently, in MM there are no clinical approaches to target this disease subset and ongoing strategies to inhibit RAS function or downstream effectors have had limited clinical success in other tumors. This has prompted our team to look into other more indirect modes of RAS-selective targeting. Oncogenic RAS-driven cancers use a unique actin-driven endocytosis pathway, termed macropinocytosis (MP), to increase the nutrient supply and sustain proliferation. To create a strategy for targeting RAS mutant MM, we have investigated whether RAS-mutant MM cells undergo MP and whether this process can be exploited as a therapeutic vulnerability, by utilizing this pro-oncogenic biochemical mechanism to selectively deliver a toxin to the MM clone using a MP selective monobody-drug conjugate (MDC). Methods The MDC relies on a proprietary fibronectin-based scaffold (monobody) identified based on its physiochemical properties that facilitates MP selective internalization, and therefore targets RAS-mutant MM tumor cells, with a very favorable pharmacokinetic profile. MMAE was attached to the monobody with a cathepsin-cleavable linker and a maleimide group for conjugation to the C-terminal free cysteine on the monobody protein (MDC-MMAE). MDC-MMAE was pre-clinically evaluated both in-vitro and in-vivo, in human MM cell lines, patient cells and a doxycycline inducible mutant KRAS cell system. Results In-vitro cell line and patient cell studies demonstrated that RAS-mutant MM cells undergo MP whereas wild type (WT) cells do not. To understand the role of mutant RAS in driving uptake of the MDC, a doxycycline-inducible mutant KRAS V12 KMS11 system was established. The functionality of the inducibility of the cell system was verified using protein expression and membrane ruffling in the presence of doxycycline. Fluorescently-labeled monobody (MDC-Cy5.5) and TMR-Dextran underwent a high level of uptake in the presence of induced mutant RAS. In contrast, in conditions where MP was absent, no uptake of MDC-Cy5.5 and TMR-Dextran was seen. Furthermore, when KMS11 KRASV12 and WT KMS11 were treated with MDC-MMAE, a 2-fold increase in cell death was observed in the mutant RAS cell line compared to wild type RAS. In-vivo studies showed that the pharmacological properties of the drug when conjugated to the monobody enabled faster serum clearance compared to antibody drug conjugates (ADCs) and nanomaterials, while maintaining cellular impermeability allowing enhanced drug uptake via MP. Importantly, in-vivo the MDC-MMAE technology had an improved toxicity profile compared to ADC-MMAE, increasing tolerable drug delivery by upwards of 15-fold. To test the anti-tumor effects in-vivo, the L363 (NRAS Q61), WT KMS11, and KMS11 KRASV12 cell lines were subcutaneously injected into MM murine models. After tumors were established, 0.5mg/kg MDC-MMAE was administered every 7 days. Mutant RAS L363 and KMS11 KRASV12 tumors treated with MDC-MMAE exhibited roughly a 6-fold decrease in tumor size after 21 days while WT KMS11 tumors showed no significant difference in tumor volume. MDC-MMAE at 5mg/kg showed complete tumor regression as a single agent in L363 tumors. Improved outcomes were seen with MDC-MMAE in combination with standard of care options at lower doses. Additionally, MDC-MMAE has displayed enhanced immunogenic cell death that has not been seen with other chemotherapeutic options, making it an ideal partner for immunotherapy combination. Conclusion Limited clinical options exist for the treatment of mutant RAS MM tumors. We show that by taking advantage of MP, a process upregulated in RAS-mutant cancers, MDC-MMAE specifically targets and inhibits MM growth and improves survival in murine models. It can also be combined with other MM standard of care drugs and with immunotherapy drugs to have a potentially important clinical effect. In collaboration with Tezcat Biosciences, the MDC-MMAE technology has achieved a phase II SBIR for advancement to clinical application.

Abstract 207: Ex vivo modeling of multiple myeloma: A novel drug sensitivity screening platform

Abstract Multiple Myeloma (MM) is a heterogeneous malignancy characterized by abnormal clonal plasma cell infiltration in the bone marrow. It is the second most common hematologic malignancy, after non-Hodgkin’s Lymphoma. This deadly disease globally affects 1 to 5 people in every 100,000 people each year. After initial diagnosis, the 5-year survival rate is 44% because there is no curative therapy, and most patients will eventually experience relapse, and some become refractory. Large inter-patient and intra-patient genetic heterogeneity limit the identification of universal drivers of MM. However, several oncogenic dependencies such as primary events related to driver gene mutations and primary translocations can be targeted for better treatment strategies for R/R multiple myeloma. To establish a robust drug sensitivity screening platform, both MM cell lines and cryopreserved primary MM patient samples were used. MM cell lines screen with H929, MM1R and RPMI-8226 was performed to narrow down optimal concentrations of investigative test agents. During assay development, a panel of FDA approved agents for relapsed MM including panobinostat, bortezomib, melphalan, omacetaxine, and selinexor were tested. The cells were seeded at 50,000 cells per well in triplicates in a 96-well plate on day 0. The test agents were added in 9 concentrations with the top concentration being 25 uM with 2-fold dilutions. After 6- days of incubation, a luminescent cell viability assay was performed to calculate relative viability with drug treatment and IC50 was computed by fitting data using a standard four-parameter logistic model. For primary multiple myeloma samples, bone marrow aspirates were collected from Multiple Myeloma patients procured from different providers. BM mononuclear (BMMNC) cells were separated by Ficoll-Hypaque density sedimentation. Unfractionated BMMNC cells were used in these assays to preserve intra-tumor heterogeneity. Primary cells were seeded in triplicates per dose point on day 0 in Champions’ proprietary media. The test agents were also added on day 0 and were incubated for 6 days. On Day 6, the relative cell viability was measured based on Cell Titer Glo readout. The cryopreserved primary MM patient samples were viable in culture for the entire assay duration validating assay feasibility. A panel of FDA approved, standard of care drugs were tested in numerous clinically well-annotated and diverse MM patient models. Primary model selection was based on disease burden including plasma cell count from Core Biopsy and BM aspirates. Multiparametric flow cytometric immunophenotyping was also performed in these primary samples using monoclonal antibodies against CD56, CD19, CD117, CD27, CD138, and CD38. For the first time, we demonstrate the feasibility of a novel, ex-vivo drug sensitivity screening platform with cryopreserved, primary multiple myeloma cells from diverse, clinically well-annotated patient samples. Citation Format: Vaishnavi Sambandam, Sharvari Inamdar, Haoting Hsu, Brandon Walling, Paolo Schiviani, Abhay Andar, Marianna Zipeto, Michael Ritchie, Karin Abarca Heidemann, Maria Mancini. Ex vivo modeling of multiple myeloma: A novel drug sensitivity screening platform [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 207.

RF01 | PMON168 Hedgehog-Induced Somatostatin Receptor Expression is Inhibited by the Activation of the Glucocorticoid Receptor Signaling Pathway in Human Pituitary Adenoma Organoids

Abstract Background Cushing's disease (CD) is an endocrine disorder caused by an ACTH-secreting pituitary adenoma that is associated with increased morbidity and mortality. Because somatostatin inhibits pituitary ACTH secretion, the somatostatin receptor subtypes (SSTR) 2 and 5 have been targets of medical therapies for CD. The SSTR5 is most consistently and strongly expressed in corticotroph pituitary tumors but the SSTR dynamics in CD during treatment and responses to cortisol level changes are far from being understood. Studies in adult stomach demonstrated that the Hedgehog (Hh) signaling pathway is critical for the regulation of somatostatin and SSTR signaling. While Hh signaling is known to be essential during the embryonic development of the pituitary and in the adult gland, the mechanism by which Hh signaling regulates SSTR expression in CD is unknown. Hypothesis Activation of glucocorticoid receptor (NR3C1, GR) results in the inhibition of Hh transcription factor GLI1 leading to reduced SSTR expression. Methods We developed a human pituitary adenoma organoid model (hPITOiPSC) from induced pluripotent stem cells treated with the glucocorticoid receptor (GR) antagonist mifepristone, and co-treated them with or without SSTR agonists pasireotide or octreotide. In a separate series of experiments, the role of Hh transcription factor GLI1 was identified using hPITOiPSC treated with mifepristone with or without GANT61 (GLI inhibitor) or ketoconazole (Smoothened, SMO inhibitor). CRISPR-Cas9 gene editing of hPITOiPSC pituitary organoids were used to model the development of pituitary corticotroph adenomas in the presence of BRAF, USP48 and USP8 mutations. Human pituitary adenoma tissue harvested fresh during pituitary surgery was used to generate pituitary corticotroph subtype adenoma organoids (hPITOs). Dose responses using standard of care drugs were performed using the hPITOs. Results 1) At baseline SSTR2 was abundantly expressed within hPITOiPSC. Mifepristone induced significant increases in ACTH secretion and POMC expression that correlated with induced SSTR2 and 5. Mifepristone-induced SSTR2 and 5 expression was significantly inhibited in the presence of GANT61, whereas SMO inhibitor ketoconazole had a minimal effect on mifepristone-induced SSTR2/5, POMC expression and ACTH secretion. Dexamethasone alone significantly inhibited both GLI1 and SSTR2 and 5. 2) While pituitary organoids that were differentiated from control iPSCs (iPSCCtrl) expressed all major hormone-producing cell lineages, there was a significant increase in ACTH expression with loss of PIT1, GH, FSH, LH and PRL in iPCSs expressing mutated BRAF, USP48 and USP8. Organoids expressing a mutation in BRAF had significantly higher SSTR2 expression levels compared to controls. 3) HPITOs generated from pituitary adenomas of CD patients showed differential organoid responses to pasireotide, mifepristone, and ketoconazole. Conclusion Within pituitary adenomas, the SSTR is a transcriptional target of Gli1, and this response is blocked by the activation of the GR. These data form the basis of combination therapy for CD with mifepristone and pasireotide. Presentation: Saturday, June 11, 2022 1:37 p.m. - 1:42 p.m., Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.

115 (PB105) - New patient derived lymphoma xenograft (PDX) panel for drug development, immuno-oncology and translational research

Lymphomas represent a very heterogeneous group of hematological malignancies and, despite successful therapies, they are a major challenge in clinical practice. Lymphomas often develop resistance to treatment with standard of care drugs (SoC) and have a high relapse rate. Therefore, new therapies are needed to improve long-term remission and patient survival. Recent advances in high-throughput molecular profiling have helped to identify genetic factors and genetic subtypes of diffuse large B-cell lymphoma (DLBCL).

Abstract 5492: Activity of RP7214, a novel, selective, and potent small molecule inhibitor of DHODH, in AML

Abstract Background: Dihydroorotate dehydrogenase (DHODH), a rate limiting enzyme in pyrimidine synthesis, is overexpressed in certain cancers and impedes tumor cell proliferation via cell cycle arrest. RP7214 is a novel and potent DHODH inhibitor that inhibited DHODH activity in enzyme and PHA induced HWB/PBMC proliferation with IC50 and EC50 values of 7.8 & 2.5/0.60 nM respectively. Herein, we describe the efficacy of RP7214 as a single agent and in combination with standard of care drugs in preclinical models of AML Methods: Cell viability of AML cell lines (U937, HL-60, THP-1, and KG-1) following incubation with RP7214 as a single agent or in combination with Azacytidine or Venetolcax for 72 h was determined in an MTT-based assay. Cell surface expression of CD11b in THP-1 and human primary bone marrow AML mononuclear cells in presence of RP7214 was evaluated by flow cytometry. Apoptosis was evaluated following incubation of cell lines with compound for 48 or 72 h, subsequent staining with Annexin-V-PE and 7-AAD, and analysis by flow cytometry. Anti-tumor potential of RP7214 as single agent was tested in subcutaneous MV-4-11 human leukemia xenograft model. Results: RP7214 inhibited AML cell proliferation in all the four cell lines tested with GI50 ranging from 2.4 to 7.6 µM. Expression of the CD11b marker on THP-1 cell surface was enhanced by 40% following incubation with 5 µM compound; effect of which was reduced to 15% in the presence of 300 µM Uridine. Incubation of primary human bone marrow AML mononuclear cells with 10 µM of RP7214 increased the CD11b+ cells by > 15 %. Combination of 3 µM-RP7214 and 1 µM-Azacytidine inhibited cell proliferation by > 25% (P < 0.05) compared to single agents in MV-4-11 cells. Similarly, combination of 3 µM-RP7214 with 3 nM Venetoclax demonstrated 15% (P < 0.05) inhibition of cell growth compared to single agents in MV-4-11 cell line. RP7214 at 3, 10, and 30 mg/kg BID demonstrated significant anti-tumor activities in both tumor size and tumor weight in subcutaneous MV-4-11 human leukemia xenograft model. Conclusions: Results demonstrate the utility of RP7214 as a single agent and in combination with standard of care drugs in inducing apoptosis and promoting differentiation to fully mature cells in AML. A Phase 2a trial in AML patients is planned. Citation Format: Srikant Viswanadha, Satyanarayana Eleswarapu, Swaroop Vakkalanka. Activity of RP7214, a novel, selective, and potent small molecule inhibitor of DHODH, in AML [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 5492.

Abstract 6223: PD3D®models: New age in cancer research and clinical diagnostics

Abstract Patient-derived 3D cell culture models (PD3D®) developed as a powerful tool for disease modelling, biomarker and drug discovery. Currently, they are gaining increasing significance in the field of personalized oncology, as they recapitulate the histopathology of the original tumor tissue and preserve its genetic markup. PD3D® can be used to model intratumoral heterogeneity and for medium and high throughput drug screens. Using a reverse clinical engineering approach, PD3D® models allow identification of chemoresistance/sensitivity signatures (i.e., biomarkers) and can be applied in personalized oncology to identify treatment for an individual patient. We successfully established PD3D® models from more than 300 tumor tissue samples, ranging from more prevalent cancers like colorectal, breast and pancreas carcinoma, to rare tumor entities including various sarcoma types and thymoma. PD3D® models from different tumor entities differ in morphology and culture media requirements. When treating PD3D® from the same tumor entity with standard of care drugs, we found that their response differed, as does clinical response of patients. Furthermore, we successfully used PD3D® models to identify a biomarker for predicting chemosensitivity towards a targeted drug. For application of PD3D® in truly personalized oncology, we developed a protocol that allows us to generate a PD3D® culture and perform a drug sensitivity assay for an individual patient within a therapy-relevant timeframe. Using this protocol, we identified a combination therapy for a pretreated, metastasized appendix carcinoma within 29 days, that resulted in stable disease of the patient. In conclusion, PD3D® models can be derived from various cancer entities and used to analyze drug response in cohorts of models for drug development or identification of signatures related to drug resistance or sensitivity. Furthermore, PD3D® models can be used to predict a patient tumor’s drug response in a personalized manner, supporting the oncologist to identify the best treatment option for the patient. Citation Format: Alina Pflaume, Samantha Exner, Katja Herrera-Glomm, Jürgen Loskutov, Ulrike Pfohl, Manuela Regenbrecht, Sushmitha Sankarasubramanian, Lena Wedeken, Sabine Finkler, Larissa Ruhe, Quirin Graf Adelmann, Christoph Reinhard, Philipp Stroebel, Christian R. Regenbrecht. PD3D®models: New age in cancer research and clinical diagnostics [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 6223.

Abstract 3980: Targeting Ewing sarcoma based on RNA expression

Abstract Purpose: Ewing sarcoma (ES) is the second most common malignant bone sarcoma in children and young adults. Current treatment for Ewing sarcoma includes a combination of cytotoxic chemotherapeutic agents and local control with radiation and/or surgery. The survival rate of those with Ewing sarcoma has seen very little improvement over the past several decades and remains dismal for those with recurrent or metastatic disease. The purpose of this study is to identify novel agents currently available for use in Ewing sarcoma. Methods: Novel targeted approaches for the treatment of ES were identified using RNA sequencing performed on 15 ES patient derived cell lines with bioinformatic analysis of gene expression. Targeted agents were tested on patient cell lines at escalating doses. At 48 hours cell viability was assessed with CellTiter-Glo 2.0 and analyzed with GraphPad Prism to determine the IC50. At 24- and 48-hours western blot analysis was performed to evaluate the effect on cell cycle and apoptosis. Combination studies with standard chemotherapy were performed to evaluate for synergy using SynergyFinder 2.0. Results: RNA analysis identified HDAC2, ALK and JAK1 as a potential therapeutic targets. The pan-HDAC inhibitor, Panobinostat, was cytotoxic to all Ewing sarcoma cell lines tested with clinically relevant IC50s (≤200nM) and repressed expression of Cyclin D1 and pRB. ALK inhibition was cytotoxic at doses slightly higher than that of clinical relevance. HDAC and ALK expression levels correlated to cell sensitivity. JAK1 inhibition does not appear to have efficacy at clinically relevant dosing. Panobinostat synergizes with Doxorubicin at clinically relevant doses. Conclusion: This work highlights that RNA expression may identify potential targets which could be effective in treating Ewing sarcoma or potentially improve the efficacy of standard of care drugs. HDAC and ALK inhibition show a decrease in cell viability in ES cell line models. Future studies of HDAC and ALK inhibitors will aim to determine efficacy in xenograft models. Citation Format: Kaitlyn Smith, Divya Gandra, Kimberly McKinney, Karl Dykema, Abhinav Nagulapally, Giselle S. Sholler, Javier Oesterheld, Erin Trovillion. Targeting Ewing sarcoma based on RNA expression [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 3980.

Abstract 177: Ex vivo 3D culture of adenoid cystic carcinoma PDX models recapitulate disease biomarkers and predict drug response

Abstract Adenoid cystic carcinoma (ACC) is a rare, glandular cancer whose incidence rate and limited 2D cell culture capability make it difficult to study primary patient samples. Although well characterized ACC patient-derived xenografts (PDX) have proven to be a useful model to study disease mechanisms and therapeutic sensitives, animal drug studies are relatively low throughput, costly, and take months to accomplish. Ex vivo 3D cell culture can provide a high-throughput, less costly, and significantly faster platform for these drug studies but are hampered by the rarity of tissue. To address this unmet need for models of rare tumor types we developed 3D spheroid (3D-XPDXs™) and microtumor (3D-XPDXmt™) models of ACC using PDX as the primary tissue source. ACC PDX cells readily formed spheroids in our 3D-XPDXs™ platform, remained viable for up to 14 days, and maintained disease-relevant biomarkers such as MYB and c-kit. 3D-XPDXmt™ represent a more complex model of ACC by incorporating extracellular matrix. ACC 3D-XPDXmt™ displayed tumor-like morphologies concordant with the parental tumors and exhibited MYB and c-kit biomarker expression for up to 56 days in culture. Drug response profiling (DRP) was performed using the 3D-XPDXs™ ACC model with KIYATEC’s validated KIYA-PREDICT™ DRP platform. The screening panel consisted of drugs and drug-like compounds currently in use or under investigation for use in ACC, including broad-spectrum chemotherapies and targeted agents. Individualized drug responses were noted for each model as they exhibited differential sensitivities to DNA-damaging agents, microtubule stabilizers, and c-kit targeting kinase inhibitors mirroring the diversity of clinical outcomes. KIYA-PREDICT™ also identified drugs and drug-like compounds that uniformly inhibited viability. This is significant because there is currently no standard of care drugs for ACC, as few, if any have demonstrated homogenous responses in test populations. Monensin has been shown to inhibit activity of the MYB transcription factor, making it an attractive candidate drug for the treatment of ACCs which have a high prevalence of MYB activating alterations. In our study, monensin was effective in all three models with IC50 concentrations in the low micromolar range. These results correlate well with immunohistochemical staining of MYB in ACC 3D-XPDXs™ and 3D-XPDXmt™. Taken together, this data represents a new ex vivo 3D cell culture platform for the study of ACC biology and potential therapies. Citation Format: Melissa Millard, Teresa M. DesRochers, Michael J. Wick, Jeffrey Kaufman, Nicole Spardy Burr. Ex vivo 3D culture of adenoid cystic carcinoma PDX models recapitulate disease biomarkers and predict drug response [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 177.

A phase 1b/2 study of batiraxcept (AVB-S6-500) in combination with cabozantinib, cabozantinib and nivolumab, and as monotherapy in patients with advanced or metastatic clear cell renal cell carcinoma (NCT04300140).

TPS4599 Background: In clear cell renal cell carcinoma (ccRCC) the constitutive expression of hypoxia induced factor 1-α leads to increased expression of AXL. AXL overexpression has been associated with the development of resistance to VEGF inhibitors and suppression of the innate immune response through inhibition of macrophage-driven inflammation. Batiraxcept is a recombinant fusion protein dimer containing an extracellular region of human AXL combined with the human immunoglobulin G1 heavy chain (Fc), which demonstrates highly potent, specific AXL inhibition. In preclinical studies using the 786-O, M62, and SN12L1 tumors, batiraxcept monotherapy resulted in a significant reduction of tumor growth compared to control. In healthy volunteer and ovarian cancer clinical studies, batiraxcept was well tolerated with no dose-related adverse events, and a maximum tolerated dose was not reached. Therefore, batiraxcept could be tested as either a monotherapy or in combination with standard of care drugs in patients with metastatic ccRCC. The Phase 1b dose-escalation portion of this study evaluated batiraxcept in combination with standard of care cabozantanib in patients who progressed on or after first line therapy. No DLT was observed at either of two batiraxcept doses evaluated. The recommended Phase 2 dose of batiraxcept has been identified as 15 mg/kg every 2 weeks (q2w) with cabozantinib 60 mg based upon safety, PK/PD, and preliminary efficacy data. Methods: This Phase 2, multi-center, open-label study includes three parts: Part A) batiraxcept 15 mg/kg q2w in combination with cabozantinib 60 mg daily for ccRCC subjects who have progressed on or after one line of therapy, n=25. Part B) batiraxcept 15 mg/kg q2w with cabozantinib 40 mg daily and nivolumab at the investigator’s choice (240 mg q2w or 480 mg q4w) for first line treatment of advanced or metastatic ccRCC subjects, n=20. If no safety signals are observed in the first 6 subjects enrolled, 10 subjects will be enrolled in the first stage of a Simon 2-stage minmax statistical design. If ≥ 6/10 subjects achieve PR or CR, stage 2 will open to enroll up to 20 total subjects. Part C) batiraxcept 15 mg/kg q2w monotherapy for subjects with advanced/metastatic ccRCC ineligible for curative intent therapies, n=10. The primary objective for each arm is objective response rate by RECIST v1.1. Secondary objectives include safety, duration of response, clinical benefit rate, progression free survival by RECIST v1.1, and overall survival. Exploratory objectives include pharmacokinetic and pharmacodynamic assessments. The Phase 2 portion of this Ph1b/2 study is currently enrolling. Clinical trial information: NCT04300140.

Establishment of PD3D models of sarcomas: A promising preclinical tool for improvement of sarcoma treatment.

e23538 Background: Compared to the progress in understanding and treating carcinomas in the past decade, the options and related clinical benefit in terms of response rates and overall survival for sarcoma patients lacks behind. Increasing incidence, low 5-year-survival rates and nearly endless heterogeneity of sarcomas are challenging oncologists every day. The necessity of so far missing representative preclinical models is obvious. PD3D cell culture models have already proven to be a useful tool to reverse clinical engineer patient outcome in carcinomas. Here we report the establishing and refining of PD3D models for the plethora of sarcoma entities. Methods: We obtained viable sarcoma tissue samples from incisional biopsies or tumor resections. We continuously optimized media conditions. For quality control and pathological evaluation, we embedded the cells in FFPE, stained patient-specific models according to original tumor samples and evaluated them pathologically. Upon histopathological evaluation, we performed semi-automated drug response assays on patient-specific models with up to 12 drugs and drug combinations, including standard of care drugs plus a selection of additional drugs. In the fashion of a prospective observatory study, we compared the results from the in vitro screen with the actual clinical outcome. Results: More than 25 patient derived 3D-cell culture models have been established from various subtypes of sarcomas. Optimized media conditions and sampling operation improved the take rates from ca. 10 to 80% irrespective of the tumor subtype. Pathological examination of the models confirmed original diagnoses and revealed that the patient-specific models recapitulate the key properties of the original tumor. Negative predictive value of drug sensitivity testing was close to 100 %, while the positive predictive value was > 80 %. These results in a limited number of cases puts the predictive value en par with recently published data about the predictive value of patient-derived organoids in carcinomas. Conclusions: Patient derived 3D-cell culture models of sarcomas can be routinely established, irrespective of subtype Models can be used for multi-omics analyses including drug sensitivity screenings Pretherapeutic drug sensitivity screenings could support clinical decision making Findings need to be confirmed in a prospective observatory trial.

The identification of the anthracycline aclarubicin as an effective cytotoxic agent for pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal types of cancer, mainly due to its delayed diagnosis and lack of effective therapeutic options. Therefore, it is imperative to find novel treatment options for PDAC. Here, we tested a series of conventional chemotherapeutics together with anthracycline compounds as single agents or in combination, determining their effectivity against established commercial and patient-derived, low-passage PDAC cell lines. Proliferation and colony formation assays were performed to determine the anticancer activity of anthracyclines; aclarubicin and doxorubicin, on commercial and patient-derived, low-passage PDAC cell lines. In addition, the effect of standard-of-care drugs gemcitabine and individual components of FOLFIRINOX were also investigated. To evaluate which mechanisms of cell death were involved in drug response, cleavage of poly(ADP-ribose)polymerase was evaluated by western blot. Aclarubicin showed superior antitumor activity compared to other anthracyclines and standard of care drugs (gemcitabine and individual components of FOLFIRINOX) in a patient-derived, low-passage PDAC cell line and in commercial cell lines. Importantly, the combination of gemcitabine and aclarubicin showed a synergistic effect at a dose range where the single agents by themselves were ineffective. In parallel, evaluation of the antitumor activity of aclarubicin demonstrated an apoptotic effect in all PDAC cell lines. Aclarubicin is cytotoxic for commercial and patient-derived low-passage PDAC cell lines, at doses lower than peak serum concentrations for patient treatment. Our findings support a (re)consideration of aclarubicin as a backbone of new combination regimens for pancreatic cancer patients.

Anisomycin is active in preclinical models of pediatric acute myeloid leukemia via specifically inhibiting mitochondrial respiration.

The poor outcomes in acute myeloid leukemia (AML) necessitate new treatments. In this work, we identified that anisomycin is a potential selective anti-AML candidate, particularly for those with FLT3-ITD mutation. We found that anisomycin potently inhibited proliferation and induced apoptosis in multiple AML cell lines. Anisomycin was effective in targeting progenitor cells isolated from all tested pediatric AML patients, while sparing normal counterparts. Using AML xenograft mouse models, anisomycin exhibited inhibitory effect on tumor growth throughout the whole duration without causing toxicity in mice. The combination of anisomycin with standard of care drugs is synergistic and selective in AML cell culture system and mouse model. In addition, FLT3-ITD cells were more sensitive to anisomycin than FLT3 WT cells. Mechanistic studies revealed that anisomycin acted on AML in a p38-independent manner. We found that anisomycin decreased mitochondrial respiration by disrupting complex I activity, leading to intracellular oxidative stress. AML ρ0 cells that lack of mitochondrial respiration exhibited resistance to anisomycin. Finally, we showed that mitochondrial biogenesis contributes to differential sensitivity of FLT3-ITD and FLT3 WT cells to anisomycin. Our work is the first to systematically demonstrate that anisomycin is a useful addition to the treatment armamentarium for AML. Our findings highlight the therapeutic value of mitochondrial respiration inhibition in AML patients harboring FLT3-ITD mutation.

Abstract 1004: Defining stearoyl-CoA desaturase 1 as a molecular therapeutic target against cholangiocarcinoma

Abstract Cancer cells increase lipid metabolism by up-regulation lipogenic enzymes such as stearoyl-CoA desaturase 1 (SCD1). It is the rate-limiting enzyme in the de novo synthesis of fatty acids (FAs), catalyzing the conversion and biosynthesis of saturated fatty acids (SFAs) into monounsaturated fatty acids (MUFAs). We developed SSI-4, a novel highly specific SCD1 inhibitor. The anti-tumor activity ofSSI-4 was examined against different cholangiocarcinoma (CCA) models that included human and mouseCCA cell lines, CCA patient-derived xenografts (PDX) NOD SCID gamma (NSG) mouse models, and CCA PDX derived organoids. Using cell proliferation assay, we examined twelve CCA cell lines and 4 were very sensitive to SSI-4 (1-40 nM IC50). The remaining CCA cell lines showed moderate to no sensitivity to SSI-4. Studies at the protein level have shown that SCD1 is present in both sensitive and non-sensitive cells. Thus, SCD1 must be present in sensitive cells but is not predictive of response to an SCD1 inhibitor. In an effort to identify biomarkers predicting response to therapy, we performed assays, such as lipid, lactate, or energy phenotype which identified elevated lactate and unsaturated fatty acid levels as well as a glycolytic energy phenotype. In vivo, CCA PDX models have demonstrated that SSI-4strongly inhibited tumor growth. Immunohistochemical analysis of CCA tumors revealed elevated glycolytic genes in sensitive cells and thus, a potential predictive biomarker. We are currently pursuing a better understanding of the relationship between glycolysis and fatty acid synthesis/metabolism. We are also testing novel combination therapy of SSI-4 with the standard of care and other drugs to develop novel treatments for CCA. Using CCA PDX derived organoids showed synergistic antitumor activity of SSI-4in combination with cancer standard of care drugs such as gemcitabine and cisplatin. Collectively, we expect to develop a biomarker-driven selection of CCA patients sensitive to SCD1 inhibitors and novel SSI-4 combination therapy leading to improved patient survival. Citation Format: Justyna J. Gleba, Laura A. Marlow, Erin E. Miller, James L. Miller, Aylin Alasonyalilar-Demirer, Yi Guo, Kabir Mody, Lewis R. Roberts, Steven R. Alberts, Mark J. Truty, Tushar C. Patel, John A. Copland. Defining stearoyl-CoA desaturase 1 as a molecular therapeutic target against cholangiocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1004.

Abstract 203: SCLC-CellMiner: An extensive cell line genomic and pharmacology resource identifies a subgroup of small cell lung cancers sensitive to targeted therapies and immunotherapies

Abstract The typical low life expectancy and limited therapeutic options for patients with small cell lung cancer (SCLC) caused the National Cancer Institute (NCI) to categorize SCLC as “recalcitrant” cancer. SCLC-CellMiner (https://discover.nci.nih.gov/SclcCellMinerCDB) integrates drug sensitivity and genomic data from 118 patient-derived SCLC cell lines, providing a unique genomic and pharmacological resource. Transcriptomic profiling validates the SCLC consensus nomenclature based on expression of 4 master transcription factors NEUROD1, ASCL1, POU2F3 and YAP1 (NAPY classification) and demonstrate differential transcriptional networks driven by these lineage specific transcription factors. Our analyses reveal transcription networks linking SCLC subtypes with MYC and its paralogs MYCL and MYCN and inactivation of the NOTCH pathway in the neuroendocrine SCLC (N, A & P subgroups). By contrast, YAP1-driven SCLC (SCLC-Y) express the NOTCH pathway and co-express both YAP/TAZ and its negative regulator genes driving the Hippo pathway. SCLC-Y cell lines show the greatest resistance to the standard of care drugs (etoposide, cisplatin and topotecan) while PI3K-AKT-mTOR inhibitors show a higher activity in this subgroup. To explore the immune pathways and the potential value of the transciption factors based classification for selecting SCLC patients likely to respond to immune checkpoint inhibitors, we explored a transcriptome signature based on 18 established native immune response and antigen-presenting genes (APM score). The SCLC-Y cell lines are the only subset expressing innate immune response genes. SCLC-CellMiner is a powerfull tool demonstrating the value of cancer cell line genomic and pharmacological databases. Our analyses suggest the potential genomic molecular classifications to select patients for targeted therapies and immunotherapy, such as patients in the SCLC-Y subgroup who may be most responsive to immune checkpoints modulators. Citation Format: Camille Tlemsani, Lorinc Pongor, Fathi Elloumi, Luc Girard, Kenneth Huffman, Nitin Roper, Sudhir Varma, Augustin Luna, Vinodh Rajapakse, Pascaline Boudou-Rouquette, Robin Sebastian, Kurt Kohn, Julia Krushkal, Mirit Aladjem, Beverly Teicher, Paul Meltzer, William Reinhold, John Minna, Anish Thomas, Yves Pommier. SCLC-CellMiner: An extensive cell line genomic and pharmacology resource identifies a subgroup of small cell lung cancers sensitive to targeted therapies and immunotherapies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 203.

Consensus statement: improvement in care and outcomes for patients with ST‐elevation myocardial infarction with timely reperfusion therapy: a pharmaco-invasive approach

The prevalence of cardiovascular diseases continues to increase in India, with a rapid epidemiological transition. Timely management of ST-elevation myocardial infarction (STEMI)is the key to decrease mortality and morbidity rates. In India, patients most often do not receive optimal therapy owing to a number of factors such as socio-economic constraints, lack of knowledge, geographical restrictions etc, leading to suboptimal outcomes. The timely delivery of optimal reperfusion strategy for STEMI patients is immensely challenging for physicians, due to several reasons. Primary percutaneous coronary Intervention (PCI) is still a global gold standard for the treatment of STEMI. Delayed case presentation is a significant challenge, especially in Indian tier towns/cities, because of prolonged transportation time or traffic delays with regards to reaching a PCI facility. Keeping in mind the accessibility to PCI facility because of geographical locations as well as affordability concerns especially in smaller Indian towns, pharmaco-invasive approach is almost as effective and a practical approach for reduction of morbidity and mortality rates. Timely establishment of reperfusion therapy is critical for improving myocardial salvage in patients with STEMI. There is an urgent need for developing strategies for efficient STEMI management, such as timely delivery of reperfusion therapy; reinforcement of health system and professionals, implementation of guideline-based interventions, streamlined insurance policy and greater emphasis on patient awareness for detection of symptoms. In addition to the timely reperfusion therapy and other standard care drugs, statins and potassium channel activators have demonstrated clinically significant improvements in the outcome of STEMI management.

Regulatory T cells for minimising immune suppression in kidney transplantation: phase I/IIa clinical trial

ObjectiveTo assess whether reshaping of the immune balance by infusion of autologous natural regulatory T cells (nTregs) in patients after kidney transplantation is safe, feasible, and enables the tapering of...