Patient-derived Primary Tumor Cells Research Articles

Prediction of Clinical Precision Chemotherapy by Patient-Derived 3D Bioprinting Models of Colorectal Cancer and Its Liver Metastases.

Methods accurately predicting the responses of colorectal cancer (CRC) and colorectal cancer liver metastasis (CRLM) to personalized chemotherapy remain limited due to tumor heterogeneity. This study introduces an innovative patient-derived CRC and CRLM tumor model for preclinical investigation, utilizing 3d-bioprinting (3DP) technology. Efficient construction of homogeneous in vitro 3D models of CRC/CRLM is achieved through the application of patient-derived primary tumor cells and 3D bioprinting with bioink. Genomic and histological analyses affirm that the CRC/CRLM 3DP tumor models effectively retain parental tumor biomarkers and mutation profiles. In vitro tests evaluating chemotherapeutic drug sensitivities reveal substantial tumor heterogeneity in chemotherapy responses within the 3DP CRC/CRLM models. Furthermore, a robust correlation is evident between the drug response in the CRLM 3DP model and the clinical outcomes of neoadjuvant chemotherapy. These findings imply a significant potential for the application of patient-derived 3DP cancer models in precision chemotherapy prediction and preclinical research for CRC/CRLM.

Chimeric antigen receptor clustering via cysteines enhances T-cell efficacy against tumor.

Chimeric antigen receptor (CAR) T-cell therapy achieves great success for hematological malignancies. However, clinical trials have revealed some limitations in both improving the efficacy and reducing the relapse, which calls for innovative strategies to engineer more powerful CAR-T cells. Promoting the formation of CAR clusters provides an alternative approach and potentially improves current CAR T-cell therapy against cancers. Here, we generated CARCys-T cells using a 4-1BB-derived hinge region including 11 cysteines residues. The cysteines in the hinge were found to facilitate CARCys clustering upon antigen stimulation and promote the antitumor activity of CAR-T cells. Compared with most conventionally used CAR-T cells with CD8α-derived hinge (CARconv-T cells), CARCys-T cells exhibited larger diameter of CAR clusters and enhanced antigen-specific tumor lysis both in vitro and in vivo. In addition, the CARCys-mediated enhancement could be applied to HER2, CD19 as well as GPC3-targeted CAR-T cells. More importantly, CARCys-T cells showed potent antitumor efficacy in clinically relevant patient-derived primary tumor cells and organoids. Thus, the novel hinge containing 11 cysteines provides a promising strategy to facilitate CAR clustering and maximize anti-tumor activity of CAR-T cells, which emphasizes the importance of CAR clustering to improve CAR T-cell therapy in the clinic.

Rapid screening for individualized chemotherapy optimization of colorectal cancer: A novel conditional reprogramming technology-based functional diagnostic assay.

BackgroundIn vitro patient tumor models such as patient-derived organoids (PDO) and conditionally reprogrammed (CR) cell culture are important for translational research and pre-clinical drug testing. In this study we present a personalized drug sensitivity test for late stage, potentially operable colorectal cancer (CRC) using patient-derived primary tumor cells isolated with i-CR technology, an optimized CR method. We explored the clinical feasibility of using i-CR platform to guide CRC chemotherapy, and established the correlation between in vitro drug sensitivity and patient clinical response. MethodsPrimary CRC tumor cells were isolated and cultured with the i-CR technology. NGS was performed and the WES and CNV results of i-CR cells were compared with that of the original patient tumor samples. In vitro drug screenings were done with guideline chemotherapy drugs for CRC. In vivo drug response was examined with paired PDX mouse models. A double-blind co-clinical cohort study was carried out and the clinical outcomes of the enrolled patients were compared with the i-CR results. Resultsi-CR platform could be used to rapidly propagate primary colorectal tumor cells that represent individual patient tumors effectively by keeping the clonal heterogeneity and the genetic characteristics. Chemotherapy drug screenings with i-CR cells were comparable with that of PDX models. More importantly, i-CR results showed high accordance with the clinical outcomes of the enrolled CRC patients. Conclusioni-CR platform was capable to test and optimize therapeutic regimens pre-clinically, study cancer cell biology, and model tumor re-emergence to identify new targeted therapeutics from an effective personalized medicine standpoint.

A reproduceable in situ xenograft model of spinal glioma

BackgroundSpinal glioma is a nervous system tumor that tends to relapse and has no specific prognostic molecular biomarkers. Thus, a stable and reproduceable animal research model of spinal glioma is urgently needed. New methodWe established a new in situ tumor xenograft model of spinal glioma using nude mice. In this study, we implanted tumors into the cervical spinal cord of nude mice to mimic the pathological characteristics of the original tumors. ResultsThrough anatomical experiments, we found that the cervical lamina of mice was thinner, the intervertebral space was much wider, and the adhesion muscles were more easily separated. According to the examination of spinal cord sections, the best puncture point we identified was located 0.9 mm lateral to the posterior median line at the level of the line between the midpoints of the scapulae and at a depth of 0.9 mm. In the nude mouse xenograft experiment, the implanted tumor tissue retained the pathological characteristics of the original tumor. Comparison with existing method(s)This model used the cervical spinal cord as the puncture site and patient-derived primary tumor cells, which has never been performed before. Tumor cells could be injected directly without damaging the lamina. Thus, we could reduce the risk of man-made spinal cord injury and infection and avoid destroying the stability and integrity of the spine. ConclusionsThis study established a stable and reliable animal model of spinal glioma for further molecular research and targeted therapy development.

Abstract 4159: Ovarian cancer ex vivo 3D tumor cultures predict patient specific drug sensitivity

Abstract Introduction While systemic treatment has been quite static in the past decade in ovarian cancer, the challenge for the coming years is to stratify patients for optimal and new treatment strategies, such as targeting DNA damage response pathways, or immune modulation. Patient primary tumor from resections, biopsy or ascites can be cultured such that tumor heterogeneity and resident immune cells are preserved. These can be used to predict treatment response in patients or to test new cancer therapies. Here we present a high throughput short-term 3D ex-vivo culture platform combined with high content image-based analysis. This platform allows visualization and quantification of standard of care therapy and new drugs on fresh and cryopreserved patient derived ovarian cancer tumoroids. Methods Patients with advanced primary or relapsing ovarian carcinoma are included in ongoing multi-center clinical trials in the Netherlands. Ovarian cancer derived tumoroids, freshly isolated or cryopreserved, are embedded in a protein-rich hydrogel and exposed to up to 20 drugs during a short term 3D culture. The automated high content imaging analysis platform measures a large panel of tumoroid morphological features, and responses such as tumor cell killing, growth arrest and local invasion are measured to define the response for each drug. In addition, clinical response data from the ongoing trials are collected to be correlated to clinical outcome of patients treated with systemic therapy. Results We present results of drug sensitivity testing in patient-derived primary tumor cells of fresh and cryopreserved ascites and solid tumor. Patient-specific drug sensitivity is identified for up to 20 drugs including standard of care (e.g. carboplatin, paclitaxel) and novel treatment strategies (e.g. PARP inhibitors). Activity of immunomodulatory drugs were also monitored successfully in vitro. Accurate response evaluation demonstrates the feasibility of high-throughput drug screening on patient primary material within OcellO's platform. Our results show a high reproducibility in testing freshly isolated or cryopreserved material, highlighting the potential of a cryopreserved collection of patient derived primary material to test new drugs. Conclusion OcellO's advanced 3D image analysis of patient primary material represents a rapid and biologically relevant approach to test various candidate compounds (e.g. antibodies, antibody-drug conjugates and small molecules) for ovarian cancer. The availability of drug response data combined with patient clinical data, including BRCA mutation and cytology/histology pathologist evaluation is expected to support drug discovery, improve the efficiency of clinical trials and establish predictive testing in the clinical setting. Citation Format: Fanny Grillet, Abbas Jariani, Juul Overkamp, Lidia Daszkiewicz, Kuan Yan, Leo S. Price, Willemijn Vader. Ovarian cancer ex vivo 3D tumor cultures predict patient specific drug sensitivity [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4159.

Bioprinting of patient-derived in vitro intrahepatic cholangiocarcinoma tumor model: establishment, evaluation and anti-cancer drug testing

Towards the development of in vivo-mimicking tumor model for extensive study of tumorigenesis and establishment of personalized therapy, patient-derived primary tumor cells were employed in this work for three-dimensional (3D) bioprinting. Intrahepatic cholangiocarcinoma cells isolated from patient were bioprinted using a composite hydrogel system of gelatin-alginate-MatrigelTM into pre-designed grid architecture. ICC cells were observed to process a colony forming ability with high survival rate and active proliferation. Expression levels of tumor markers, cancer stem cell markers, matrix metalloproteinase protein, index of tumor fibrosis, index of liver function, and epithelial-mesenchymal transition regulatory proteins confirmed the development of the invasive and metastatic phenotype of the intrahepatic cholangiocarcinoma cells in the 3D printed tumor microenvironment. Similar results were obtained in anti-cancer drug resistance of the intrahepatic cholangiocarcinoma cells in the 3D bioprinted construct that demonstrated stem-like properties, which suggested the promising potential of current 3D printed tumor model in the development of personalized therapy, especially for discovery of more conducive targeted drugs.

MDL-800, an allosteric activator of SIRT6, suppresses proliferation and enhances EGFR-TKIs therapy in non-small cell lung cancer.

Sirtuin 6 (SIRT6), a member of the sirtuin family, is a nicotinamide adenine dinucleotide (NAD+)-dependent deacetylase that is involved in various physiological and pathological processes. SIRT6 is generally downregulated and linked to tumorigenesis in non-small cell lung carcinoma (NSCLC), thus regarded as a promising therapeutic target of NSCLC. In this study, we investigated whether MDL-800, an allosteric activator of SIRT6, exerted antiproliferation effect against NSCLC cells in vitro and in vivo. We showed that MDL-800 increased SIRT6 deacetylase activity with an EC50 value of 11.0 ± 0.3 μM; MDL-800 (10-50 μM) induced dose-dependent deacetylation of histone H3 in 12 NSCLC cell lines. Treatment with MDL-800 dose dependently inhibited the proliferation of 12 NSCLC cell lines with IC50 values ranging from 21.5 to 34.5 μM. The antiproliferation effect of MDL-800 was significantly diminished by SIRT6 knockout. Treatment with MDL-800 induced remarkable cell cycle arrest at the G0/G1 phase in NSCLC HCC827 and PC9 cells. Furthermore, MDL-800 (25, 50 μM) enhanced the antiproliferation of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) in osimertinib-resistant HCC827 and PC9 cells as well as in patient-derived primary tumor cells, and suppressed mitogen-activated protein kinase (MAPK) pathway. In HCC827 cell-derived xenograft nude mice, intraperitoneal administration of MDL-800 (80 mg · kg-1 · d-1, for 14 days) markedly suppressed the tumor growth, accompanied by enhanced SIRT6-dependent histone H3 deacetylation and decreased p-MEK and p-ERK in tumor tissues. Our results provide the pharmacological evidence for future clinical investigation of MDL-800 as a promising lead compound for NSCLC treatment alone or in combination with EGFR-TKIs.

Abstract B047: Advanced glycation end products promote prostate tumor growth and are a potential biologic consequence of lifestyle factors contributing to cancer disparity

Abstract Advanced glycation end-products (AGEs), are reactive metabolites produced endogenously as a consequence of glucose uptake during glycolysis. AGEs accumulate in tissues and organs as we grow older to promote multiple chronic disease phenotypes. AGE pathogenic effects are mediated through modification of protein function, genetic fidelity, stress responses and cellular signaling pathways. Critically, cancer disparity factors such as a sedentary lifestyle, obesity and an unhealthy diet are external influences that also contribute to the AGE accumulation pool in the body. This research group examined circulating and tumor AGE levels in clinical specimens of prostate cancer and identified a race specific, tumor-dependent pattern of accumulation. AGE levels were highest in aggressive tumors, especially those from men with African ancestry. Increased AGE levels correlated with an upregulation in the receptor for advanced glycation end products (RAGE) and activated NFkB. In a syngeneic subcutaneous prostate cancer mouse model, chronic consumption of AGE resulted in a 3-fold increase in tumor growth. Strikingly, dietary-AGE mediated increases in tumor growth were accompanied by a cytoplasmic accumulation of AR, elevation in MYC, RAGE, and AGE as well as increased cell proliferation. Cytoplasmic accumulation of AR is elevated in CRPC tissue and is an independent predictor of biochemical recurrence. Our data show that treatment of prostate cancer cells with AGEs induces a neuroendocrine differentiated phenotype by promoting a more mesenchymal morphology and increasing the expression of associated marker genes including ENO2, MYC and SYP and the prostate cancer stem cell marker CD44 as well as the downregulation of AR. The aberrant activation and recruitment of immune cells is a major pathogenic consequence of AGE accumulation, and a series of studies have highlighted the tumor-associated immune response as a critical pathway contributing to cancer disparity. Using patient-derived primary tumor cells, the investigators found that AGEs released into the extracellular matrix may recapitulate the tumor-associated immune response observed in ancestry-specific prostate tumor tissues. Further preliminary studies indicate that AGE treatment of prostate cancer cells can alter how cancer cells metabolize glucose to promote an aggressive phenotype. The investigators' studies support the concept that AGE metabolites represent a biologic consequence of the socioeconomic and environmental factors that promote cancer health disparity. As our understanding of tumor biology advances, it is becoming increasingly clear that these inter-related lifestyle factors have distinct molecular consequences on the biologic makeup of tumors, altering cell signaling events and gene expression profiles to contribute to cancer disparity outcomes such as its earlier development or its progression to more aggressive disease. Citation Format: Pamela Woods, Bradley A. Krisanits, Dion Foster, Lourdes M. Nogueira, Laura Spruill, Marvella E. Ford, Michael B. Lilly, Victoria J. Findlay, David P. Turner. Advanced glycation end products promote prostate tumor growth and are a potential biologic consequence of lifestyle factors contributing to cancer disparity [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr B047.

Metabolism-based GP-2250 in combination with gemcitabine as a novel approach to pancreatic cancer: A mouse xenograft study.

e16750 Background: GP-2250, a novel oxathiazine derivative, displayed apoptotic cytotoxicity against various tumor cell lines but not normal cells. It was therefore tested whether its antineoplastic potential - alone or in combination – could be leveraged specifically against pancreatic cancer. Methods: GP-2250 is a cancer metabolism-based therapeutic. It depleted metabolic energy through inhibition of the enzyme GAPDH (glyceraldehyde-3-phosphate dehydrogenase) which is rate limiting for aerobic glycolysis. ATP was decreased in a time- and dose-dependent manner in pancreatic tumor cell lines and ROS was increased. Mitochondrial dysfunction was triggered by an increased expression of Bax and decreased expression of Bcl2, leading to apoptosis. Cytotoxicity of GP-2250 was ROS-dependent. It was blocked by N-acetylcysteine. Results: GP-2250 substantially increased the sensitivity of pancreatic tumor cells to various chemotherapeutics in particular to gemcitabine (Gem). At doses which were inactive or barely active per se, the combination of GP-2250 and Gem caused striking cytotoxicity in patient-derived primary tumor cells in vitro, pointing to a strong synergy between the two agents. This finding was substantiated in vivo by patient-derived xenograft (PDX) studies in nude mice. While GP-2250 and Gem, given as monotherapy (500 mg/kg and 50 mg/kg respectively, 2x/week), showed only a limited antineoplastic response, the combination treatment resulted in a significantly higher anti-tumor activity as shown in further PDX. Tumor regression was found in 5 out of 9 PDX based on RECIST criteria. Stable disease was reached in 3 of the remaining grafts. In 1 xenograft, which was unresponsive to Gem, the combination treatment nevertheless achieved a reduction in tumor growth which significantly exceeded that of GP-2250 monotherapy. Conclusions: GP-2250 is a novel cancer metabolism-based therapeutic. GP-2250, in combination with Gem, strongly reduces tumor growth in patient-derived xenografts exceeding by far the response to monotherapy. GP-2250 is being evaluated in a Phase I clinical trial in patients diagnosed with advanced pancreatic cancer (Clinical Trial NCT03854110).

Diphenhydramine increases the therapeutic window for platinum drugs by simultaneously sensitizing tumor cells and protecting normal cells.

Platinum‐based compounds remain a well‐established chemotherapy for cancer treatment despite their adverse effects which substantially restrict the therapeutic windows of the drugs. Both the cell type‐specific toxicity and the clinical responsiveness of tumors have been associated with mechanisms that alter drug entry and export. We sought to identify pharmacological agents that promote cisplatin (CP) efficacy by augmenting the levels of drug‐induced DNA lesions in malignant cells and simultaneously protecting normal tissues from accumulating such damage and from functional loss. Formation and persistence of platination products in the DNA of individual nuclei were measured in drug‐exposed cell lines, in primary human tumor cells and in tissue sections using an immunocytochemical method. Using a mouse model of CP‐induced toxicity, the antihistaminic drug diphenhydramine (DIPH) and two methylated derivatives decreased DNA platination in normal tissues and also ameliorated nephrotoxicity, ototoxicity, and neurotoxicity. In addition, DIPH sensitized multiple cancer cell types, particularly ovarian cancer cells, to CP by increasing intracellular uptake, DNA platination, and/or apoptosis in cell lines and in patient‐derived primary tumor cells. Mechanistically, DIPH diminished transport capacity of CP efflux pumps MRP2, MRP3, and MRP5 particularly in its C2+C6 bimethylated form. Overall, we demonstrate that DIPH reduces side effects of platinum‐based chemotherapy and simultaneously inhibits key mechanisms of platinum resistance. We propose that measuring DNA platination after ex vivo exposure may predict the responsiveness of individual tumors to DIPH‐like modulators.

Taxotere Induces Dephosphorylation of MET in Patient-derived Tumor Models.

Although molecular targeting therapy is an attractive treatment for cancer, resistance eventually develops in most cases. Here, we evaluated chemotherapeutic efficacy on non-small cell lung cancer (NSCLC) with acquired resistance to epidermal growth factor receptor inhibitors mechanistically. Antitumor effects of taxotere were evaluated using multiple models, including xenograft, and patient-derived models developed from adenocarcinoma cancer patients. Protein expressions were analyzed after drug treatment. Taxotere inhibited tumor growth of NSCLC cells harboring drug resistance, and reduced the expression of phosphorylated MET proto-oncogene, receptor tyrosine kinase (MET). A tumor-inhibitory effect of taxotere was also demonstrated in vivo in xenografts in mice, patient-derived primary lung tumor cells and patient-derived xenograft with concomitant repression of phosphorylated MET expression. Chemotherapeutic and MET-targeting drug exhibited a synergistic cell growth-inhibitory effect. These results suggest that the anticancer drug taxane may be an adjuvant for lung tumors exhibiting enhanced signaling of MET networks.

Abstract B139: Patient specific drug sensitivity to novel treatment approaches in ovarian cancer ex vivo 3D tumor cultures

Abstract Background: Many new drugs and treatment strategies are in development for ovarian cancer. While systemic treatment has been quite static in the past decade, the challenge for the coming years is to stratify ovarian cancer patients for optimal treatment strategies, like targeting DNA damage response pathways or immune modulatory approaches. Patient primary tumor material collection offers cryopreserved viable primary tumor cell clusters, containing the whole heterogeneity found in the patient ascites (including potential immune cells) to predict treatment response in patients or to test new cancer therapies. Here we present a high throughput short-term 3D ex-vivo culture platform combined with high content image-based analysis. This platform allows visualization and quantification of standard of care therapy and new drugs on fresh and cryopreserved patient derived ovarian cancer tumoroids. Methods: Patients with ovarian carcinoma are included in ongoing multi-center clinical trials in the Netherlands. Ovarian cancer derived primary tumoroids, freshly isolated or cryopreserved, are embedded in a protein-rich hydrogel and exposed to up to 20 drugs during a short term 3D culture. The automated high content imaging analysis platform measures a large panel of tumoroid morphological features, and responses such as tumor cell killing, growth arrest and local invasion are measured to define the response for each drug. In addition, clinical response data from the ongoing trials will be correlated to clinical outcome of patients treated with systemic therapy. Results:We present first results of drug sensitivity in patient-derived primary tumor cells of fresh and cryopreserved ascites. Patient-specific drug sensitivity is identified for up to 20 drugs including standard of care (e.g. carboplatin, paclitaxel) and novel treatment strategies (e.g. PARP inhibitors). Accurate response evaluation demonstrates the feasibility of high-throughput drug screening on patient primary material within OcellO’s platform. Our results show a high reproducibility in testing freshly isolated or cryopreserved material, highlighting the potential of a cryopreserved collection of patient derived primary material to test new drugs. Conclusion: OcellO’s advanced 3D image analysis of patient primary material represents a rapid and biologically relevant approach to test various candidate compounds (e.g. antibodies, antibody-drug conjugates and small molecules) for ovarian cancer. The availability of drug response data combined with patient clinical data, including BRCA mutation and cytology/histology pathologist evaluation is expected to support drug discovery, improve the efficiency of clinical trials and establish predictive testing in the clinical setting. Citation Format: Fanny Grillet, Abbas Jariani, Juul Overkamp, Lidia Daszkiewicz, Kuan Yan, Leo Price, Willemijn Vader. Patient specific drug sensitivity to novel treatment approaches in ovarian cancer ex vivo 3D tumor cultures [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B139. doi:10.1158/1535-7163.TARG-19-B139

PRMT5 Is a Key Epigenetic Regulator That Promotes Transcriptional Activation in Mantle Cell Lymphoma By Regulating the Lysine Methyltransferase SETD7 and MLL1 Activity

Introduction: Post-translational histone modifications directly modify chromatin structure to influence a wide variety of cellular events including gene expression, DNA replication and repair, and cell cycle control. While histone lysine methylation can confer either transcriptionally active or repressive states, the symmetric dimethylation of arginine residues on histone tails is generally associated with transcriptional repression. Overexpression and dysregulation of PRMT5, the major type II protein arginine methyltransferase, has been shown to drive cellular proliferation and survival of multiple cancer types including mantle cell lymphoma (MCL), a subtype of non-Hodgkin lymphoma associated with poor prognosis. Our work has shown that PRMT5 drives the symmetric dimethylation of arginine (histones H3R8 and H4R3) and attenuates RB/E2F regulatory pathways leading to the expression and activation of the PRC2 lysine methylation programs. We have previously shown that PRMT5 promotes constitutive expression of the WNT/β-CATENIN target genes (MYC, CCND1, and SURVIVIN) via the epigenetic repression of AXIN2 and WIF1 regulatory genes. This PRMT5 mediated epigenetic program allows for constitutive activation of WNT and PI3/AKT downstream pathways relevant to MCL growth and survival. The inhibition of PRMT5 triggers histone deacetylation and H3K4me3 demethylation on promoters of β-CATENIN target genes. H3K4 is modified by several enzymes containing SET domains including the SETD7 and MLL1 proteins. We hypothesized that PRMT5 inhibition, through its ability to repress AKT phosphorylation, would regulate SETD7 and MLL1 activity and regulate downstream pathways relevant to lymphomagenesis. Methods: PRMT5 inhibition of patient-derived MCL cell lines and primary lymphoma tumor cells was achieved with sh-PRMT5 lentivirus (or sh-GFP control) and utilization of a selective small molecule, SAM-competitive PRMT5 inhibitor (PRT382). Gene and protein expression was monitored by reverse transcription (RT) real time PCR and western immunoblotting, respectively. Recruitment of target proteins to promoter regions was examined by ChIP-PCR assays. Interactions within the transcriptional complex were examined by co-immunoprecipitation. Cellular growth and apoptosis was assessed by proliferation assays and FACS analysis. Results: Inhibition of PRMT5 by shRNA-mediated knock down or treatment with PRT382 (Prelude Therapeutics) reduced H3K4me2 in MCL cells via indirect epigenetic repression of SETD7. ChIP-PCR studies showed PRMT5 to be recruited to the SETD7 promoter, suggesting that the activity of PRMT5 promoted the transcription of this lysine methyltransferase. Our findings show that reduced phosphor-AKT by PRMT5 inhibition inhibits dimerization of the MLL1 complex leading to dissociation of MLL1 from the transcriptional activation complex and decreased H3K4me1 and H3K4me3. PRMT5 inhibition led to dissociation of the BCL9- Pygopus-MLL1 transcriptional activating complex and to assembly of repressive LSD1 (the histone demethylase affecting H3K4me3)-HDAC2 (the histone lysine deacetylase) containing complexes. Furthermore, PRMT5 inhibition led to differentially enhanced recruitment of this repressive LSD1/HDAC2 complex and decreased H3K9Ac and H3K14Ac epigenetic marks on promoters of β-CATENIN target genes. PRMT5 inhibition regulates lysine methylation at H3K4 through epigenetic silencing of SETD7 and MLL1 activity, as well as histone H3 acetylation driven by histone acetyltransferase KAT2A. ChIP-Seq studies examining SETD7 and PRC2 recruitment in context of PRMT5 inhibition are currently underway. Conclusions: Our observations show that dysregulated PRMT5 activity acts as a master epigenetic regulator affecting arginine and lysine histone marks. PRMT5 can act directly to repress target tumor suppressor genes while simultaneously indirectly activating SETD7 and MLL1 to drive transcriptional activation of key oncogenes that promote the proliferation and survival of MCL. These results support the notion that inhibiting PRMT5 leads to erasure of repressive histone arginine and lysine marks and promote the restoration of normal growth and survival checkpoints in this disease. Disclosures Scherle: Prelude Therapeutics: Employment. Vaddi:Prelude Therapeutics: Employment. Baiocchi:Prelude: Consultancy.

Abstract 98: Stromal-targeting with quercetin in patient-derived models of head and neck squamous cell carcinoma (HNSCC)

Abstract Head and neck squamous cell carcinoma (HNSCC) is an aggressive cancer with a high recurrence rate. Recurrences occur in ~25% cases of early -stage patients (Stage I-II) and 50-60% cases of advanced stage (Stage II-IV) patients. Cumulative evidences suggest that tumor stroma, especially cancer-associated fibroblast (CAF) plays a protective role and contributes to drug-resistance in HNSCC, leading to recurrences after treatment. Quercetin is a flavonoid purified from natural plants, such as green tea, onions and berries. It has been reported to suppress CAFs and reduce collagen accumulation surrounding tumors, potentially facilitating drug delivery to tumors. Here, we hypothesize that quercetin targeting of CAFs may enhance the anti-tumor efficacy of cisplatin, and potentially other antitumor therapies in HNSCC. Using a primary co-culture system with primary HNSCC cells (70%) and the paired CAFs (30%) from HNSCC patients, we investigated the effect of quercetin and cisplatin combination treatment in vitro. We found that combination of quercetin and cisplatin elicited a significantly greater growth inhibition (70% of inhibition) as compared to 37% of inhibition with cisplatin and 15% of inhibition with quercetin alone. This result appeared to demonstrate some anti-CAF effects and antitumor effects exerted by this combination strategy.Using patient-derived HNSCC primary tumor cells, stromal-rich xenografts were successfully developed in vivo. The stromal-suppressive effect of quercetin was then examined upon treatment with increasing doses of quercetin (DMF, 2.5, 5 or 10 μM in 5 microliter volume, 2 times injection). Potential alteration of the tumor architecture by quercetin (vs. vehicle treatment) was examined by H&E staining. A marked reduction of stromal component was found in quercetin -treated tumors vs. vehicle-treated tumors. Importantly, we also found that these quercetin-treated tumors have 80.4% reduction in α-SMA protein expression (6.0% in vehicle vs.1.2% in treatment group), strongly indicating a significant stromal suppressive action of quercetin in an HNSCC primary culture-derived xenograft model. Furthermore, quercetin (10 μM) treatment reduced collagen expression by ~80% (vs. vehicle treatment) in the HNSCC primary culture-derived xenograft model by Masson’s trichrome staining. In conclusion, quercetin can effectively suppress the activated status of CAFs and may potentially enhance anti-tumor effect of cisplatin in an HNSCC patient-relevant manner. The antitumor efficacy of quercetin combination strategies should warrant further investigations. Citation Format: Hui Li, Wenying Piao, Pik Yuk Lau, Chin Wang Lau, Jason Ying Kuen Chan, Yu Xiong Su, Leaf Huang, Kai Li Hu, Vivian Wai Yan Lui. Stromal-targeting with quercetin in patient-derived models of head and neck squamous cell carcinoma (HNSCC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 98.

Exploring Cancer Cell Behavior In Vitro in Three-Dimensional Multicellular Bioprintable Collagen-Based Hydrogels.

In vitro cancer 3D models are valuable tools to provide mechanistic insight into solid tumor growth, invasion, and drug delivery. The 3D spheroid model of solid tumors has been the most popular cancer model in use until now. However, previous studies have shown that these spheroid models lack sufficient morphological parameters, which may affect their response to chemicals. In this work, we proposed the fabrication of miniaturized 3D cancer models using collagen type I-based bioprintable bioinks. In the context of a mimicking model for advanced neuroblastoma studies, we showed that cancer cells contained in bioprintable bioinks formed Homer Wright-like rosettes, maintained their proliferative capacities and produced an equivalent Vimentin-rich matrix unlike that of non-bioprintable bioinks which made for poorer models. In addition, bioprintable bioinks were successfully bioprinted as compartmentalized 3D models in the centimeter scale, which was not feasible using non-bioprintable bioinks. In contrast to non-bioprintable hydrogels, we did not observe contraction in their bioprintable counterparts, which is an advantage for prospective 3D bioprinted models that should attain stable rheological and mechanical properties after bioprinting. By adopting this proposed system for the use of patient-derived primary tumor cells, the approach could be introduced as a first line strategy in precision medicine for testing the response of neuroblastoma cells to drugs, especially when disease progresses rapidly or patients do not respond to actual therapy regimens.

Abstract 887: The effect of anticancer chemotherapeutics on immune microenvironment of lung adenocarcinoma with EGFR mutation in vivomicroenvironment of lung adenocarcinoma with EGFR mutation in vivo

Abstract Lung cancer is the leading cause of cancer related deaths worldwide. Molecular targeting therapy is an attractive treatment for lung cancer, although it eventually develops resistance in most cases. In this report, we tested taxan antitumor effect on lung adenocarcinomas in vitro and in vivo. It could inhibit cell growth of many NSCLC cells tested, exhibiting reduced expression of c-MET and STAT3. The nascent effect of taxan on lung tumor cells were also proved on patient-derived primary lung tumor cells and patient-derived xenograft model that highly expresses c-MET. The antitumor effect of this chemotherapeutics was also observed on T790M mutant cells. Interestingly, the antitumor effect of taxan was synergistic in combination of c-Met inhibitor on lung tumor cells as well as patient-derived primary lung tumor cells. However, single treatment of taxan was sufficient for halting tumor growth in vivo, as no combinational effect of c-Met inhibitor was obvious. Not only c-Met inhibitor but also taxan reduced phosphorylated c-MET and STAT3, although cytokines on downstream of c-MET and STAT3 were explosively increased in vitro setting resulting in high expression of chemokines/cytokines. Importantly, the effect was not true in in vivo setting, in which the expressions of chemokines/cytokines as well as phosphorylated c-MET and STAT3 were influenced with this agent. These results suggest that taxane is one of the comparative adjuvant for lung tumors exhibiting targeted drug resistance, especially for enhanced signaling of MET-STAT-immuno-microenvironment. Citation Format: Young-Ah Suh, Hyemin Mun, Sun-Hye Lee, Se-Young Jo, Ju-Hee Oh, Chu-Hee Lee. The effect of anticancer chemotherapeutics on immune microenvironment of lung adenocarcinoma with EGFR mutation in vivomicroenvironment of lung adenocarcinoma with EGFR mutation in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 887.

Identification and Characterization of a Small-Molecule Inhibitor of Wnt Signaling in Glioblastoma Cells

Glioblastoma multiforme (GBM) is the most common and prognostically unfavorable form of brain tumor. The aggressive and highly invasive phenotype of these tumors makes them among the most anatomically damaging human cancers with a median survival of less than 1 year. Although canonical Wnt pathway activation in cancers has been historically linked to the presence of mutations involving key components of the pathway (APC, β-catenin, or Axin proteins), an increasing number of studies suggest that elevated Wnt signaling in GBM is initiated by several alternative mechanisms that are involved in different steps of the disease. Therefore, inhibition of Wnt signaling may represent a therapeutically relevant approach for GBM treatment. After the selection of a GBM cell model responsive to Wnt inhibition, we set out to develop a screening approach for the identification of compounds capable of modulating canonical Wnt signaling and associated proliferative responses in GBM cells. Here, we show that the small molecule SEN461 inhibits the canonical Wnt signaling pathway in GBM cells, with relevant effects at both molecular and phenotypic levels in vitro and in vivo. These include SEN461-induced Axin stabilization, increased β-catenin phosphorylation/degradation, and inhibition of anchorage-independent growth of human GBM cell lines and patient-derived primary tumor cells in vitro. Moreover, in vivo administration of SEN461 antagonized Wnt signaling in Xenopus embryos and reduced tumor growth in a GBM xenograft model. These data represent the first demonstration that small-molecule-mediated inhibition of Wnt signaling may be a potential approach for GBM therapeutics.

Abstract 2794: Ex vivo chemoresponse assay using patient-derived tumor xenografts in combination with high content imaging platform as models for oncology drug development.

Abstract Current strategies for developing new anticancer drugs rely heavily on preclinical testing in cancer cell lines and their derived in vivo cell line xenograft models. The value of a predictive assay is heavily dependent on the extent to which it can recapitulate the biology of disease. It has been reported that heterogeneity of cell populations within the tumor microenvironment has significant correlation with the efficacy of any treatment regimen. Cell line models fail to recapitulate the heterogeneous nature of tumor. The purpose of this study was to investigate whether the use of patient-derived primary tumor cells (PTC) could be expanded as xenografts for in vitro chemosensitivity assays to predict clinical outcomes in anticancer drug testing. We have developed preclinical cancer models using PTCs grown in 3D cultures that better mimic in vivo conditions. One of the disadvantages of using patient derived cells is the limited number of cells available from biopsy samples. We utilized patient-derived xenografts (PDX) as a strategy to expand the human tumor cells in mice, while taking efforts to retain the actual tumor biology of the patient. We used high content imaging to evaluate colony segmentation, morphological features, proliferative and apoptotic endpoints to determine efficacy of oncology drug candidates. We conducted a retrospective study using PTCs from solid tumor indications including endometrial and lung to evaluate the correlation between various models and usefulness in predicting the outcome of a specific drug candidate. Our results indicate that PDX models in combination with 3D PTC models have predictive value and enable secondary interrogation beyond single agent anti-proliferative activity to better profile the antitumor activity of targeted agents. Improved preclinical models are required to advance our understanding of the molecular aberrations that underpin cancer and are critical for developing and deploying targeted therapies that will improve patients’ lives. Citation Format: Mansi Garg, Martin Vo, Jill Ricono, Thomas Broudy, Cyrus Mirsaidi, Kesavan Nair Praveen. Ex vivo chemoresponse assay using patient-derived tumor xenografts in combination with high content imaging platform as models for oncology drug development. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2794. doi:10.1158/1538-7445.AM2013-2794

Non-small cell lung cancer stem/progenitor cells are enriched in multiple distinct phenotypic subpopulations and exhibit plasticity

Cancer stem cells (CSCs) represent a population of cancer cells that possess unique self-renewal and differentiation characteristics required for tumorigenesis and are resistant to chemotherapy-induced apoptosis. Lung CSCs can be enriched by several markers including drug-resistant side population (SP), CD133pos and ALDHhigh. Using human non-small cell lung adenocarcinoma cell lines and patient-derived primary tumor cells, we demonstrate that SP cells represent a subpopulation distinct from other cancer stem/progenitor cell (CS/PC) populations marked by CD133pos or ALDHhigh. The non-CS/PCs and CS/PCs of each subpopulation are interconvertible. Epithelial-mesenchymal transition (EMT) promotes the formation of CD133pos and ALDHhigh CS/PC subpopulations while suppressing the SP CS/PC subpopulation. Rac1 GTPase activity is significantly increased in cells that have undergone EMT, and targeting Rac1 is effective in inhibiting the dynamic conversion of non-CS/PCs to CS/PCs, as well as the CS/PC activity. These results imply that various subpopulations of CS/PCs and non-CS/PCs may achieve a stochastic equilibrium in a defined microenvironment, and eliminating multiple subpopulations of CS/PCs and effectively blocking non-CS/PC to CS/PC transition, by an approach such as targeting Rac1, can be a more effective therapy.

Abstract 5270: Evaluation of Cell-able spheroid culture system for culturing patient derived primary tumor cells

Abstract Tumor cell microenvironment has significant impact on growth kinetics, cell signaling and response to drug treatments. 3D models are more biologically relevant models compared to 2D models and have gained preference among researchers and drug developers. It is well recognized that primary tumor cell cultures grown in 2D monolayer quickly lose the ability to proliferate while 3D culture conditions on extracellular matrix allows for spheroid formation and proliferation. Cell-able, a novel micropatterned plate has cell adhesion areas in the well bottom where the size and shape of these areas are tightly controlled. Micro-fabrication of the well bottom enables rapid cell attachment and spheroid formation. Cell-able plates are potentially an alternative to culturing cells in 3D without extracellular matrix. We have evaluated spheroid formation, morphology, duration of viability, histopathology and expression of markers in patient-derived primary tumor cells from different tumor types when cultured on Cell-able plates compared to Cultrex extracellular matrix (ECM) coated plates. In addition we have utilized Cell-able plates to grow patient-derived tumor cells and evaluate the anti-proliferative responses to cytotoxic and targeted agents using high content imaging coupled with immunofluorescence characterization enabling subpopulation analysis within the spheroids. Our results indicate that patient-derived tumor cells from multiple indications as well as tumor cell lines can be cultured on Cell-able plates as spheroids that resemble the micro architecture of tumors and are therefore a suitable 3D model. The results of high content imaging analysis suggest that Cell-able plates could be used as a valuable tool in in vitro predictive assay models in oncology drug development. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5270. doi:1538-7445.AM2012-5270