bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 185: Longitudinal aqueous humor sampling reflects treatment response in retinoblastoma patients
Authors: Polski Ashley , Xu Liya , Prabakar Rishvanth K. , Kim Jonathan W. , Kuhn Peter , Cobrinik David , Hicks James , Berry Jesse L.
Published: September 2020

Purpose: The aqueous humor (AH) liquid biopsy for retinoblastoma (RB) facilitates in vivo sampling of tumor-derived cell-free DNA (cfDNA). We previously demonstrated that tumor-derived somatic copy number alterations (SCNAs) in AH predict poor ocular salvage. However, whether AH sampling can be used to monitor clinical response throughout therapy remains unknown. In this retrospective study, we hypothesize that SCNA amplitude (amp) and tumor fraction (TFx) of RB cfDNA in the AH correspond to treatment response over time.

Methods: Eyes that required intravitreal chemotherapy (IVM) for tumor seeding and had ≥3 sequential AH samples extracted during active IVM therapy and/or at secondary enucleation between 2015-2019 were included. Shallow whole-genome sequencing of AH cfDNA was performed to assess RB SCNA amp, and ichorCNA software estimated cfDNA TFx based on SCNAs present. Eyes without SCNAs in any sample were removed from final analysis. For each eye, clinical treatment response (regression vs progression) at each sample timepoint relative to the initial sample timepoint was determined from clinical records. Mann-Whitney U test was used for statistical analyses.

Results: Twenty eyes of 20 patients had ≥3 AH extractions during the study period; 6 eyes had no SCNAs and were excluded from final analysis. Disease progression at any timepoint was associated with significantly higher SCNA amp (1.65±0.34) and TFx (0.57±0.36) than disease regression (SCNA amp 1.22±0.34, P=0.0002; TFx 0.29±0.34, P=0.01). Relative increases in SCNA amp (Δamp 1.19±0.35) and TFx (ΔTFx 3.68±5.27) from start to end of longitudinal AH sampling were associated with overall disease progression, whereas relative decreases in SCNA amp (Δamp 0.78±0.08; P=0.005) and TFx (ΔTFx 0.55±0.52; P=0.006) were associated with overall disease regression.

Conclusions: We demonstrate that increases and decreases in AH-derived SCNA amp and TFx during therapy tend to correspond to clinical progression and regression of disease, respectively. Our findings suggest that longitudinal AH evaluation throughout active RB therapy may provide a novel quantitative method of monitoring RB treatment response.

Citation Format: Ashley Polski, Liya Xu, Rishvanth K. Prabakar, Jonathan W. Kim, Peter Kuhn, David Cobrinik, James Hicks, Jesse L. Berry. Longitudinal aqueous humor sampling reflects treatment response in retinoblastoma patients [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 185.
Abstract 1854: Oridonin inhibits cell growth of esophageal carcinoma cells via induction of apoptosis
Authors: Zhang Xiaojun , Xing Mengtao , Ma Yangcheng , Wang Xiao , Zhang Jianying
Published: September 2020

Esophageal Cancer estimated leading deaths are more than 400,000 every year in worldwide, while 80% due to esophageal squamous cell carcinoma. In worldwide, esophageal cancer leading death ranks in sixth among cancer leading causes of death, while the 5-year survival rate of esophageal cancer is 19%. Oridonin, a tetracyclic diterpenes compound, has been indicated the anti-tumor activity for digestive system tumors. To assess the anticancer activity of oridonin on esophageal cancer, we performed cell proliferation experiment of oridonin on esophageal squamous cell carcinoma cell line TE-8 using SRB assay. We found that IC50 of oridonin on TE-8 treated for 72h is 3.0μM, which is better than positive control Gemcitabine treatment on TE-8 for 72h (5.7 μM), as well as TE-8 cells shrunk and floated with increasing concentration on oridonin. At the same time, oridonin induced a dose-dependent inhibition of cell colony formation of esophageal cancer cell line. Colony numbers of TE-8 cell line treated with 1μM and 2μM oridonin are 111 and 54, respectively, which are significantly different (p<0.05). Accompanying with marked morphological changes, flow cytometer results showed that oridonin triggered sub-G0/G1 cell cycle arrest in a dose-dependent manner. After treatment by 10μM and 20μM oridonin for 24h, percentage of sub-G0/G1 cells were 25.5 and 55.3%, respectively, which are significantly different (p<0.05). The apoptosis results showed that oridonin treatment led to the accumulation of cells in early-(Annexin V+/PI-) and late-stage (Annexin V+/PI+) apoptosis in a dose-dependent manner.

Citation Format: Xiaojun Zhang, Mengtao Xing, Yangcheng Ma, Xiao Wang, Jianying Zhang. Oridonin inhibits cell growth of esophageal carcinoma cells via induction of apoptosis [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 1854.
Abstract 1864: Generation of a triple-mutation (T790M/C797S/L858R) NSCLC cell line for relevant drug discovery and development
Authors: Ma Huiying , Li Peixue , Zhang Peiran , Sun Fuyun , Lin Qing
Published: September 2020

Epidermal Growth Factor Receptor (EGFR) overexpression is observed in a large subset of patients with non-small-cell lung cancer (NSCLC) and correlated with poor prognosis. Current approved treatment for EGFR mutation-positive NSCLC has been revolutionized with three generations of EGFR tyrosine kinase inhibitors (TKIs): the first- and second-generation TKIs, such as gefitinib, erlotinib and afatinib, selectively targeting EGFR activating mutations existing in exon 19 and 21; and the third-generation EGFR-wild-type sparing, irreversible activating mutations/T790M inhibitor, osimertinib. Patients with somatic activating mutations in the EGFR gene have dramatic response initially, but would eventually develop resistance to these TKIs. One leading evidence of osimertinib resistance is mediated by occurrence of the point mutation C797S. There are no effective therapeutic strategies to overcome this triple-mutation (activating mutations/T790M/C797S) mediated resistance. Therefore, it is urged to develop new drug to target this particular mutant. There is still lack of triple-mutation in vitro model for the new generation drug discovery. In this study, a triple-mutation NSCLC model was generated in the NCI-H1975 lung cancer cell line, which harbors other naturally occurring EGFR genomic aberrations - double-mutation (T790M/L858R) - inherent in NSCLC. We utilized the CRISPR/Cas9 genome editing tool to target endogenous loci in human NSCLC cell line NCI-H1975 and created the intend point mutation, resulting in the triple mutation cell line (T790M/C797S/L858R). Further phenotypic analysis demonstrated that the triple-mutation cell line was resistant to the third generation inhibitors in contrast to the parental double-mutation cell line. This newly developed triple-mutation lung cancer cell line provided a very useful tool for oncology drug discovery for NSCLC.

Citation Format: Huiying Ma, Peixue Li, Peiran Zhang, Fuyun Sun, Qing Lin. Generation of a triple-mutation (T790M/C797S/L858R) NSCLC cell line for relevant drug discovery and development [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 1864.
Abstract 1873: Drivers of secondary resistance to anti-EGFR therapy in metastatic colorectal cancer
Authors: Noseir Soha Hussein , Hahn Stephan , Maghnouj Abdelouahid , Ladigan Swetlana
Published: September 2020

Secondary Resistance (SR) evolves in virtually all metastatic colorectal cancers (mCRC) treated with anti-EGFR targeting drugs such as Cetuximab (Cmab). Yet, SR patient-derived xenograft (pdx) models are largely lacking. Here, we established eight SR pdx models through chronic Cmab treatment of drug-sensitive mCRC pdx. All pdx models were initially wild-type for KRAS, NRAS, PI3K and BRAF, as required for Cmab treatment. Post SR establishment, two models showed KRAS mutations and were excluded from further studies. Whole exome sequencing of the remaining six SR pdx models did not reveal any known driver mutations which could confer SR. However, global gene expression analyses identified widespread transcriptional reprograming with many genes able to activate KRAS and/or PI3K signaling pathways. Among the highly dysregulated genes, fibroblast growth factors FGF13, FGF19, FGF20, and insulin-like growth factor IGF2 stood out as potential drivers of SR through upregulation of RTK signaling.

Functional molecular analyses of these factors were performed using lentiviral vector mediating gene transduction. Cell viability, proliferation assays and western blot (WB) analyses were applied to assess the molecular functionality of FGFs and IGF2-ligands in vitro. Finally, transgenic cell lines were injected into nude mice to test their therapeutic response towards Cmab treatment following upregulation or downregulation of the chosen candidates.

Stable lentiviral overexpression of FGF13 and IGF2 in drug-sensitive cell lines and pdx models triggered SR both in vitro and in vivo. WB analyses showed that FGF13 and IGF2 overexpression induced phosphorylation of pAKT, pS6, and pERK. Conversely, knockdown of IGF2 in a cell line with high endogenous IGF2 expression improved Cmab sensitivity. Lastly, when subjecting a Cmab SR pdx model with high endogenous overexpression of FGF13 and FGF19 to a Pan-FGF inhibitor (LY2874455) in combination with Cmab, we observed a conversion of the SR into partial response.

Taken together, these results support a role of IGF2 and FGFs as candidate proteins conferring SR in an autocrine fashion in the setting of KRAS wild-type mCRC under chronic anti-EGFR treatment. Importantly, these results also suggest that potential combination therapies of Cmab and an IGF2 or FGF inhibitor could prevent establishment of SR through these pathways and offer new treatment opportunities for patients with SR mCRC.

Citation Format: Soha Hussein Noseir, Stephan Hahn, Abdelouahid Maghnouj, Swetlana Ladigan. Drivers of secondary resistance to anti-EGFR therapy in metastatic colorectal cancer [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 1873.
Abstract 1887: Tumor-stroma interactions mediated by Semaphorin 6A as a determinant of drug resistance in BRAF-mut melanoma
Authors: Loria Rossella , Falcone Italia , Martile Marta Di , Caprara Valentina , Fraioli Rocco , Laquintana Valentina , Bon Giulia , Rosanò Laura , Bufalo Donatella Del , Ciuffreda Ludovica , Ferraresi Virginia , Milella Michele , Falcioni Rita
Published: September 2020

In BRAF-mutant (BRAF-mut) melanoma combined BRAF/MEK inhibition increases survival. However, pharmacological effects on the genetically “normal” tumor microenvironment (i.e. paradox MAPK activation) may set the stage for the development of drug resistance.

In melanoma specimens, we observed a significant correlation between BRAF-mut and the expression of Semaphorin 6A (Sema6A), a member of the semaphorin family that regulates actin cytoskeleton remodeling, motility and cell proliferation. In BRAF-mut melanoma cell lines, Sema6A is involved in cytoskeleton remodeling by regulation of YAP activity. Sema6A depletion induced a decrease in RhoA activation and, consequently, an increase in phospho-YAP and a reduction in cell proliferation rate. We thus hypothesized that actin cytoskeleton remodeling and dynamic evolutions may play a role in both cell autonomous and stroma-mediated mechanisms of drug-resistance in this context.

To assess the functional relevance of Sema6A expression in the regulation of melanoma/stroma interactions and sensitivity/resistance to pathway inhibitors, we performed an inducible Sema6A knock down in BRAF-mut melanoma cell lines and evaluated the response to BRAF/MEK inhibitors in monolayer and 2D co-culture systems. In contexts of partial response or resistance in vitro, BRAF inhibitors, alone or combined with MEK inhibitors, were increased Sema6A expression at the mRNA and protein levels in both monolayer and 2D co-culture systems. Furthermore, Sema6A silencing performed in 2D co-culture system abrogated the protective effect of melanoma/stroma interactions, resulting in a synergistic effect with BRAF/MEK inhibitors.

Overall, our results suggest that Sema6A could be a crucial mediator of protective tumor/stroma interactions, involved in resistance to MAPK inhibition in melanoma.

Citation Format: Rossella Loria, Italia Falcone, Marta Di Martile, Valentina Caprara, Rocco Fraioli, Valentina Laquintana, Giulia Bon, Laura Rosanò, Donatella Del Bufalo, Ludovica Ciuffreda, Virginia Ferraresi, Michele Milella, Rita Falcioni. Tumor-stroma interactions mediated by Semaphorin 6A as a determinant of drug resistance in BRAF-mut melanoma [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 1887.
Abstract 1896: Whole transcriptome analysis identifies TNS4 as a key effector of cetuximab and a regulator of the oncogenic activity of KRAS mutant colorectal cancer cell lines
Authors: Kim Sujin , Kim Nayoung , Kang Keunsoo , Kim Wonkyung , Won Jonghwa , Cho Jeonghee
Published: September 2020

Targeting of activated epidermal growth factor receptor (EGFR) with therapeutic anti-EGFR monoclonal antibodies (mAbs) such as cetuximab and panitumumab has been used as an effective strategy in treatment of colorectal cancer (CRC). However, its clinical efficacy occurs only in the limited number of patients. Here, we performed whole-transcriptome analysis in xenograft mouse tumors induced by KRASG12D mutation-bearing LS174T CRC cells following treatment with either cetuximab or PBS. By integrated analyses of differential gene expression with TCGA and CCLE public database, we identified TNS4, overexpressed in CRC patients and KRAS mutation-harboring CRC cell lines, significantly downregulated by cetuximab. While ablation of TNS4 expression via shRNA results in significant growth inhibition of LS174T, DLD1, WiDr, and DiFi CRC cell lines, conversely, its ectopic expression increases the oncogenic growth of these cells. Furthermore, TNS4 expression is transcriptionally regulated by MAP kinase signaling pathway. Consistent with this finding, selumetinib, a MEK1/2 inhibitor, suppressed oncogenic activity of CRC cells and this effect is more profound in combination with cetuximab. Altogether, we propose that TNS4 plays a crucial role in CRC tumorigenesis and that suppression of TNS4 would be an effective therapeutic strategy in treating a subset of cetuximab-refractory CRC patients including KRAS activating mutations.

Citation Format: Sujin Kim, Nayoung Kim, Keunsoo Kang, Wonkyung Kim, Jonghwa Won, Jeonghee Cho. Whole transcriptome analysis identifies TNS4 as a key effector of cetuximab and a regulator of the oncogenic activity of KRAS mutant colorectal cancer cell lines [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 1896.
Abstract 1908: Kinome rewiring upon acquisition of resistance to PI3K inhibitors in ER+ breast cancer
Authors: Griffin Jacqueline Reedy , Traphagen Nicole , Kettenbach Arminja , Miller Todd
Published: September 2020

Hyperactivation of the phosphatidylinositol-3 kinase (PI3K) pathway is a critical step in oncogenesis and plays a role in the development of treatment resistance in estrogen receptor-positive (ER+) breast cancer. Targeted inhibition of PI3K (PI3Ki) was recently approved in combination with endocrine therapy for advanced ER+ breast cancer. As most tumor-targeted therapies are encumbered by the development of secondary resistance, there remains a need to identify novel therapeutic strategies to prevent and overcome PI3Ki resistance. We treated mice bearing anti-estrogen-resistant ER+ breast cancer xenografts with the anti-estrogen fulvestrant +/- the pan-PI3Ki GDC-0941. The drug combination induced partial regression of tumors, followed by regrowth despite continued drug treatment. We harvested tumors before, during, and after acquisition of resistance to the drug combination and performed quantitative phosphoproteomic profiling. Using LC-MS/MS, we identified 203 phosphopeptides and 227 unique phosphorylation sites in the drug-resistant tumors, with clusters of 87 upregulated and 116 downregulated phosphopeptides. The NetPhorest analysis platform predicted hyperactivation of 6 kinases and hypoactivation of 16 kinases in drug-resistant tumors. Notably, two hyperactive kinases, MAPK1 and HIPK2, were predicted to target substrates MARKS (at Ser27 in the calcium binding domain) and NS1BP (at Ser322 in the homeodomain kelch repeat). MARCKS is a filamentous actin cross-linking protein, while the kelch repeats of NS1BP are known to associate with F-actin to stabilize actin filaments. In addition, the most significant predicted kinase among the cluster of 116 downregulated phosphopetides in the drug-resistant tumors was “PKCiota”, predicted to target PARD3 at Ser852. Previous work showed that PARD3 is central for the formation of tight junctions. These data collectively suggest a dynamic role of kinase-substrate interactions involved in resistance to combined anti-estrogen/PI3Ki treatment, including filamentation actin formation and stabilization, as well as the deregulation of tight junction formation.

Citation Format: Jacqueline Reedy Griffin, Nicole Traphagen, Arminja Kettenbach, Todd Miller. Kinome rewiring upon acquisition of resistance to PI3K inhibitors in ER+ breast cancer [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 1908.
Abstract 1922: Tamoxifen detection by molecular fluorescence in breast cancer patients as a screening for metabolizer classification
Authors: Costa Lorenna Larissa Ferreira , de Freitas Daniel Lucas Dantas , de Lima Kassio Michell Gomes , Lajus Tirzah Braz Petta
Published: September 2020

Breast cancer patients with polymorphic changes in the CYP2D6 gene show considerable variations in tamoxifen (TMX) bioavailability due to the need for bioactivation of this drug. Therefore, patients with such allelic changes have a worse prognosis compared to controls. Biospectroscopy allows the analysis of biofluids, providing the complete characterization of all molecules present in the biological matrix. Among spectroscopic techniques, molecular fluorescence stands out for its high analytical sensitivity in the broad identification of information obtained by the excitation-emission fluorescence matrix (EEM). This allows the specific measurement of fluorescent species in the sample. Quantification of TMX by fluorescence spectroscopy provides a phenotypic assessment of the patient's pharmacological metabolizing status, leading to a personalized and effective pharmacological therapy. We applied fluorescence spectroscopy to blood samples from n=20 women, who had genotyping of the CYP2D6*4_g.1846G>A allele, which confers decreased protein activity. We were able to demonstrate that the fluorescence signal generated by the TMX structure in plasma solution could be detected using our methodology. The data collected exhibited signal interference due to the numerous molecular species present in this matrix. However, using multivariate statistical algorithms we could extract relevant information from the analyte, improving the signal / noise of the emission-excitation matrix. Finally, we were able to demonstrate that low cost method, which can be performed rapidly, may allow for a simple point of care stratification of patients by the CYP2D6 status, which in turn may allow for increased personalization of tamoxifen therapy for breast cancer patients.

Citation Format: Lorenna Larissa Ferreira Costa, Daniel Lucas Dantas de Freitas, Kassio Michell Gomes de Lima, Tirzah Braz Petta Lajus. Tamoxifen detection by molecular fluorescence in breast cancer patients as a screening for metabolizer classification [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 1922.
Abstract 1928: Study of copy number amplification and chemo-response in triple negative breast cancer
Authors: Grainger Jordan Mark , Yu Jia , Kalari Krishna R. , Vedell Peter , Thompson Kevin , Goetz Matthew P. , Suman Vera J. , Boughey Judy C. , Wang Liewei
Published: September 2020

Triple negative breast cancer (TNBC) accounts for 15-20% of breast cancer cases in the United States. With currently no targeted therapies for TNBC, identification of novel biomarkers to improve chemo-response is vital. Recently, copy number amplifications (CNAs) have been implicated in treatment response in several diseases including breast cancer. Our clinical studies have associated a 5 Mb CNA in TNBC patients with chemo-response, which may elucidate novel biomarkers and treatment strategies for TNBC. Analysis of RNAseq and Whole Exome Sequencing data from 42 TNBC patient tumors enrolled in the BEAUTY Study, identified a 5 Mb CNA on chromosome 8q which associated with pathological complete response following taxane and anthracycline chemotherapy. By performing siRNA knockdown cytotoxicity studies in TNBC cell lines for genes within this amplified region, we identified RDH10 as a potential novel biomarker for increasing chemo-sensitivity. RDH10 is the rate limiting step in the synthesis of all-trans retinoic acid (ATRA). Previous studies have demonstrated ATRA to be a potent inhibitor of PIN1, a key regulator of several oncogenic signaling pathways, amplified in TNBC. We discovered overexpression of RDH10 to increase endogenous levels of ATRA, contributing to the degradation of PIN1 and taxane sensitivity. A rescue experiment with PIN1 was able to restore the chemo-resistance phenotype. Similarly, we found treating TNBC cells with ATRA phenocopied RDH10's effect on PIN1 and improved chemo-sensitivity. Furthermore, analyses of chemo-responsive PDX tumors containing the 5 Mb CNA, overexpressed RDH10 and exhibited lower levels of PIN1 when compared to non-responders. In conclusion, RDH10 amplification increases endogenous levels of ATRA and degrades PIN1 in TNBC. ATRA-mediated degradation of PIN1 sensitizes TNBC to chemotherapy, suggesting RDH10 as a novel biomarker for chemo-response and ATRA as a novel treatment to improve chemo-sensitivity.

Citation Format: Jordan Mark Grainger, Jia Yu, Krishna R. Kalari, Peter Vedell, Kevin Thompson, Matthew P. Goetz, Vera J. Suman, Judy C. Boughey, Liewei Wang. Study of copy number amplification and chemo-response in triple negative breast cancer [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 1928.
Abstract 1937: BPR6K609: An Aurora kinase inhibitor targeting small cell lung cancer with MYC amplification
Authors: Chi Ya-Hui , Chang Chun-Ping , Ke Yi-Yu , Lin Wen-Hsing , Wang Wan-Ping , Tsai Chia-Hua , Chen Yen-Ting , Su Yu-Jie , Hung Ming-Chun , Wu Zhong-Wei , Wu Mine-Hsine , Yeh Teng-Kuang , Chen Ching-Ping , Song Jen-Shin , Chen Chiung-Tong , Shih Chuan
Published: September 2020

Small cell lung cancer (SCLC) accounts for approximately 15% of all lung cancers, leading to ~30,000 deaths each year in the United States. SCLC patients often present with metastasis at time of diagnosis, excluding surgery as a treatment option. While patients show high response rate to standard chemotherapy such as cisplatin/etoposide, they soon develop drug resistance and disease progression. Therefore, new therapeutic strategies are urgently needed for SCLC. BPR6K609S0 is a novel Aurora kinase inhibitor which has been designed to inhibit the kinase activity of Aurora A, and induces proteasome-mediated degradation of MYC. The BPR6K609S0 active molecule provokes cell apoptosis and inhibits proliferation of several SCLC cell lines with IC50 < 100 nM. Oral administration of BPR6K609 induces >60 % tumor regression in a NCI-H446 xenograft mouse model. In addition, BPR6K609 further reduces tumor progression in NCI-H446 xenograft mice pre-treated with LY3295668, an Aurora A-selective inhibitor which is currently under clinical investigation. These results support the clinical potential of BRP6K609S0 for the treatment of SCLC.

Citation Format: Ya-Hui Chi, Chun-Ping Chang, Yi-Yu Ke, Wen-Hsing Lin, Wan-Ping Wang, Chia-Hua Tsai, Yen-Ting Chen, Yu-Jie Su, Ming-Chun Hung, Zhong-Wei Wu, Mine-Hsine Wu, Teng-Kuang Yeh, Ching-Ping Chen, Jen-Shin Song, Chiung-Tong Chen, Chuan Shih. BPR6K609: An Aurora kinase inhibitor targeting small cell lung cancer with MYC amplification [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 1937.
Abstract 1956: In vitro and in vivo characterization of novel MAT2A allosteric inhibitors
Authors: Pei Zhonghua , Alam Muzaffar , Bhola Neil , Cleary Leah , Drummond Jake , Fisher Marcus , Fleury Melissa , Garcia Candy , Givmanesh Atieh , Linghu Xin , McSpadden Ethan , Mounir Zineb , Neilan Claire , Newby Zach , Perumal Senthil , Steel Richard , Sutton James , Vaidya Kedar , Wagle Marie-Claire , Wang Jianhong , Yao Bing , Lackner Mark , Dillon Michael P.
Published: September 2020

Background: MAT2A (Methionine adenosyltransferase 2A) catalyzes the formation of S-adenosylmethionine (SAM) from methionine and ATP. PRMT5, a highly conserved protein arginine methyltransferase that is required for cell proliferation, uses SAM as its methyl donor. PRMT5 activity is inhibited by increased MTA levels in methylthioadenosine phosphorylase (MTAP)-deleted tumor cells. MTAP-deleted tumor cells are thus more vulnerable to MAT2A inhibition compared to MTAP-WT cells. This synthetic lethality between MTAP and MAT2A suggests that MAT2A inhibitors may be useful as anti-tumor agents in the MTAP-deleted cancers, which occurs in ~ 15% of all cancers.

Results: We have designed, synthesized and evaluated a novel series of small-molecule MAT2A inhibitors that are very potent in biochemical assays. Co-crystal structures of inhibitor-MAT2A complexes were solved and shed light on binding mode and key interactions. Biochemical mechanistic studies suggested that these compounds are allosteric inhibitors of MAT2A and are non-competitive inhibitors of MAT2A with respect to both ATP and methionine. These compounds displayed potent cellular anti-proliferation activity as well as cellular SAM modulation along with desired DMPK properties. Optimized compounds, upon oral dosing, demonstrated significant PD marker modulation and tumor growth inhibition in HCT116 MTAP-null and several endogenous MTAP-null xenograft mouse models. These agents demonstrated an acceptable safety profile in 7-day oral repeat dose tolerability studies in the rat.

Citation Format: Zhonghua Pei, Muzaffar Alam, Neil Bhola, Leah Cleary, Jake Drummond, Marcus Fisher, Melissa Fleury, Candy Garcia, Atieh Givmanesh, Xin Linghu, Ethan McSpadden, Zineb Mounir, Claire Neilan, Zach Newby, Senthil Perumal, Richard Steel, James Sutton, Kedar Vaidya, Marie-Claire Wagle, Jianhong Wang, Bing Yao, Mark Lackner, Michael P. Dillon. In vitro and in vivo characterization of novel MAT2A allosteric inhibitors [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 1956.
Abstract 1960: Targeted androgen receptor (AR) protein degradation for the treatment of metastatic castration-resistant prostate cancer (mCRPC)
Authors: Han Xin , Zhao Lijie , Xiang Weiguo , Qin Chong , Miao Bukeyan , Xu Tianfeng , Lu Jianfeng , Wang Mi , Wang Shaomeng
Published: September 2020

Androgen receptor (AR) and its downstream signaling play a critical role in the development and progression of both localized and metastatic prostate cancer. As a validated therapeutic target for the treatment of metastatic castration-resistant prostate cancer (mCRPC), previous strategies that successfully target AR signaling have focused on blocking androgen synthesis by drugs such as abiraterone and inhibition of AR function by AR antagonists such as enzalutamide and apalutamide (ARN-509). However, such agents become ineffective in advanced prostate cancer with AR gene amplification, mutation and alternate splicing. It is very clear however that in most patients with CRPC, the AR protein continues to be expressed and tumors are still dependent upon AR signaling.

Here we describe our design, synthesis and evaluation of small-molecule AR degraders based on the proteolysis targeting chimera (PROTAC) concept and our investigation of their therapeutic potential and mechanism of action in vitro and in vivo. In vitro, our potent AR degraders effectively induce degradation of AR protein in AR+ LNCaP, VCaP and 22Rv1 prostate cancer cell lines with DC50 values as low as 1 nM. AR degraders are capable of reducing the AR protein level by >95% in these AR+ cancer cell lines and effectively reduces AR-regulated gene expression suppression. In vivo, our AR degrader showed potent AR degradation effects and anti-tumor activities in multiple murine xenograft models of prostate cancer at well-tolerated dosing schedules. Our data provides clear evidence that targeting AR for degradation by the PROTAC methodology is a novel and very exciting therapeutic approach for the treatment of mCRPC.

Citation Format: Xin Han, Lijie Zhao, Weiguo Xiang, Chong Qin, Bukeyan Miao, Tianfeng Xu, Jianfeng Lu, Mi Wang, Shaomeng Wang. Targeted androgen receptor (AR) protein degradation for the treatment of metastatic castration-resistant prostate cancer (mCRPC) [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 1960.
Abstract 1972: The significance of liquid biopsy in colorectal cancer via GeneReader NGS Systems
Authors: Mujde Cem , Hanta Abdullah , Sonmezler Ozge , Rencuzogullari Ahmet , Boga Ibrahim , Bisgin Atil
Published: September 2020

Background: In terms of precision medicine, not only tumoral tissue samples but also with liquid biopsy for somatic variants detection, have been used routinely. It also helps to overcome the resampling difficulties that require an invasive procedure with the problem of tumor heterogeneity. With the Next Generation Sequencing (NGS) method which is accepted as the gold standard in molecular genetic testing, colorectal cancer patients ccfDNA (Circulating Cell-Free DNA) samples were next generation sequenced via a targeted multigene panel.

Methods: In our study, liquid biopsy samples of 63 colorectal cancer patients whom referred to Cukurova University AGENTEM (Adana Genetic Diseases Diagnosis and Treatment Center) were sequenced via GeneReader NGS Systems (Qiagen). The multi-gene panel which includes cancer related actionable 11 genes (KRAS, NRAS, KIT, BRAF, PDGFRA, ALK, EGFR, ERBB2, ERBB3, ESR1 and RAF1) were used to identify the variants of drug sensitivity and resistance. Sequencing data were analyzed by QCI-Analyze and QCI-Interpret bioinformatics tools.

Results: Forty-three clinically significant variants detected in 53.96% (n=34) of 63 patients. Total of 43 clinically significant variants in 7 genes (KRAS, NRAS, KIT, BRAF, EGFR, PDGFRA and ERBB2) were detected according to the ACMG (American College of Medical Genetics) and AMP (Association for Molecular Pathology) criteria in which 13.95%, 41.86% and 41.86% prospectively related to drug resistance, treatment sensitivity, and both treatment sensitivity and drug resistance. Moreover, 2.33% were classified as uncertain clinical significance due to data mining. Variants detected upon gene names were listed in Table 1.

Table 1:Genes and variants distribution in colorectal cancer patientsGene NameVariantsTotal %KRASp.G12A,p.G12C,p.G12D,p.G12V,p.G13S,p.G15S,p.A18V,p.I21M,p.A59T,p.A146T32.56KITp.M541L20.93BRAFp.T559I,p.V600E,p.K601R,p.R603*,p.P632S,p.639I20.93EGFRp.E282K,p.H773R,p.H773P,p.V834A,p.G863D11.63PDGFRAp.E241A,p.Y555H4.65NRASp.G13C,p.E31V,p.Q61R6.98ERBB2p.P1170V2.33

Conclusion: In terms of identifying potential target therapy options without the need of a invasive intervention becomes available with NGS multigene panel studies within high reliability that also have an effect on the quality of life in colorectal cancer patients.

Citation Format: Cem Mujde, Abdullah Hanta, Ozge Sonmezler, Ahmet Rencuzogullari, Ibrahim Boga, Atil Bisgin. The significance of liquid biopsy in colorectal cancer via GeneReader NGS Systems [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 1972.
Abstract 1982: Development of reference material for blood tumor mutational burden measurement
Authors: Butler Matthew G. , Konigshofer Yves , Clement Omoshile , Anfora Andrew , Brudzewsky Dan , Anekella Bharathi , Garlick Russell
Published: September 2020

Tumor mutational burden (TMB) is a measurement of the somatic mutations acquired by a tumor genome that cause nonsynonymous changes in proteins. TMB is a biomarker that serves as a proxy for the potential to produce neoantigens that will be recognized by T cells. Despite some reports to the contrary, TMB has successfully categorized the likelihood that an individual will respond positively to immune checkpoint inhibitors in some clinical trials. Although most TMB measurements are made from genomic DNA extracted from formalin-fixed and paraffin-embedded tissue sections, some diagnostic tests measure TMB in circulating tumor DNA (ctDNA) extracted from blood samples; an approach referred to as blood TMB (bTMB). Blood TMB is an attractive biomarker since it bypasses many of the obstacles encountered with resected and hard to biopsy tumors. Only a handful of diagnostic laboratories measure bTMB and their analytic validations rely on hard to obtain specimens acquired from ongoing drug trials or tissue repositories. This specimen scarcity impedes in depth analytic assay validation and the generation of harmonized bTMB data. For bTMB measurements to become routine, robust, and accessible to all diagnostic laboratories, we developed contrived patient-like bTMB reference materials. Blood TMB reference materials were formulated by blending and sizing genomic DNA purified from tumor and corresponding normal cell lines by proprietary methodology. Fragment analysis demonstrated that the bTMB reference materials mimic the size distribution typical of purified ctDNA. Sequencing by a targeted gene panel showed the bTMB reference materials had variant allele frequencies (VAFs) characteristic of ctDNA. For example, bTMB reference materials produced with either 2.0 or 0.5% tumor content had mean VAFs of approximately 1.0 and 0.3 %, respectively. Additional sequencing of bTMB reference materials by other gene panels demonstrated comparable results. Evaluation of contrived bTMB reference materials with various cancer gene panels will assist in the standardization of the measurement of bTMB, an emerging biomarker for clinical utility of immune checkpoint inhibitor therapy.

Citation Format: Matthew G. Butler, Yves Konigshofer, Omoshile Clement, Andrew Anfora, Dan Brudzewsky, Bharathi Anekella, Russell Garlick. Development of reference material for blood tumor mutational burden measurement [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 1982.
Abstract 2008: Pan-cancer profiling of the effect of biopsied site on tumor mutational burden measurements in a real-world data cohort
Authors: Papillon-Cavanagh Simon , Gao Chuan , Han G. Celine , Walsh Alice M.
Published: September 2020

Background: Tumor mutational burden (TMB) has been associated with efficacy of immune checkpoint therapy and is being investigated as a potential biomarker in several tumor types. The foundational studies evaluating TMB in clinical trials have not examined factors that may affect TMB estimates in real-world practice, such as the site of biopsy relative to the tumor tissue of origin.

Methods: We used the Flatiron Health/Foundation Medicine Clinico-Genomic Database (Presley CJ, et al. JAMA 2018; Singal G, et al. JAMA 2019), which contains deidentified patient-level clinical records from Flatiron Health (New York, NY), combined with genomic sequencing test results of tissue TMB from Foundation Medicine (Cambridge, MA). We examined patient records from 7 advanced cancer types: non-small cell lung cancer (NSCLC), breast cancer (BC), gastric/esophageal cancer (G/EC), melanoma (MEL), metastatic castration-resistant prostate cancer (CRPC), head and neck cancer (H&N), and small cell lung cancer (SCLC). We performed a multivariate mixed-model linear regression to test for associations between the site of tissue biopsy and TMB measurement. We used a cutoff of 10 mutations per megabase (mut/Mb) to classify specimens as high TMB.

Results: TMB data were available for 11,928 biopsy specimens from 11,567 patients: NSCLC, n = 5556; BC, n = 3381; G/EC, n = 1335; MEL, n = 528; CRPC, n = 506; H&N, n = 342; SCLC, n = 280. In multiple cancer types, we found that TMB estimates were significantly associated with the biopsied site. For example, brain metastasis specimens from patients with NSCLC had higher TMB (median 11.3 mut/Mb) than specimens collected from primary lung tissue (median 7.0 mut/Mb) or from pleura or pleural fluid (median 3.5 mut/Mb). TMB measurements were higher in brain metastases than in samples from the primary tissue across multiple cancer types. In contrast, biopsies from lymph nodes showed different TMB patterns depending on the cancer type. Consistent with those results, the proportion of patients with high TMB differed significantly by biopsied site.

Conclusion: We used a real-world database of clinical data linked with genomic tests to evaluate TMB values across tissue biopsy sites for multiple cancer types. Our results highlight the biopsied site as a potential source of variation for TMB results measurements in a cancer type–specific manner. This will be important to consider when performing research in heterogenous data sets.

Citation Format: Simon Papillon-Cavanagh, Chuan Gao, G. Celine Han, Alice M. Walsh. Pan-cancer profiling of the effect of biopsied site on tumor mutational burden measurements in a real-world data cohort [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 2008.
Abstract 2041: Lesion pathology and oral-cancer associated pain in the 4NQO oral carcinogenesis model
Authors: Naik Keyur , Janal Malvin N. , Chen Jason , Bandary Daniel E. , Brar Branden , Bhattacharya Aditi
Published: September 2020

Oral cancer is a painful and debilitating type of cancer. Oral cancer patients frequently experience severe pain while eating and talking. Pain is attributed to neuronal sensitization by the release of chemical mediators from the cancer cells and cancer microenvironment. Not all oral cancers are painful. Patients with painful oral cancers are more likely to have worse prognosis and metastatic disease, and their pain is not well managed with NSAIDs or opioid analgesics. Therefore, there is an unmet clinical need to identify the underlying mechanisms of oral cancer pain. This study was designed to identify pathological lesions associated with increased pain in a preclinical model of oral cancer and pain. Forty C57BL/6 female mice were treated with 4-nitroquinoline 1-oxide (4NQO) for 16 weeks, and followed for the development of tongue lesions for 12 weeks. Concurrently, change in nociceptive behavior (i.e., the animal equivalent of pain behavior) was measured using a validated operant assay and device for measuring functional mechanical allodynia (the dolognawmeter). Nociception (pain) scores and histopathological data were obtained from 36 animals. Mice developed a spectrum of tongue and esophageal lesions including hyperkeratoses, papillomas (exophytic lesions), dysplasias and cancers. Papillomas included lesions with benign and dysplastic pathological features, indicating that both lesion types were in the continuum of malignant transformation. Mice harbored lesions associated with low pain scores (n=9), intermediate pain scores (n=16) and high pain scores (n=11). Three pathological subsets of squamous cell carcinomas (SCCs) were identified that displayed stromal invasion (iSCC), deep stromal invasion >1.5mm depth (diSCC) and cancers with exophytic and invasive morphology associated with papillary lesions (pSCCs). Increased nociceptive behavior was associated with pSCCs in univariate and multivariate analyses. Cancers of the pSCC subtype are expected to be enriched for expression and release of nociceptive mediators. The study demonstrates that the 4NQO model recapitulates human cancer with respect to development of cancers differing in level of cancer associated nociception.

Citation Format: Keyur Naik, Malvin N. Janal, Jason Chen, Daniel E. Bandary, Branden Brar, Aditi Bhattacharya. Lesion pathology and oral-cancer associated pain in the 4NQO oral carcinogenesis model [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 2041.
Abstract 2079: Ceramide nanoliposomes a novel therapeutic option for androgen receptor negative prostate cancer
Authors: Costa-Pinheiro Pedro , Heher Abigail , Raymond Michael , Jividen Kasey , Fox Todd , Kester Mark
Published: September 2020

Prostate cancer (PCa) is estimated to account for 20% of newly diagnosed cancers and 10% of cancer-related deaths in US men during 2019. Prostate is a hormone-responsive gland that depends on male hormones, such as testosterone, for its normal growth and development. These hormones also play a role on the onset and progression of PCa. The androgen receptor (AR) is the main nuclear receptor activated by these hormones and regulates several key cellular pathways that contribute to worsening of the disease. Several antagonists for AR have been developed, as well as drugs that block the conversion of precursor steroids to testosterone. These drugs are extremely efficacious in patients, however within 24 months virtually all tumors recur and progress to castration resistant PCa (CRPC), a stage of disease that ultimately leads to death from PCa. To address this lack of efficacy and lack of therapeutics for CRPC, we decided to investigate the potential of ceramide nanoliposomes (CNL) as a new modality for PCa in preclinical models. Ceramide is a sphingolipid, a class of bioactive lipids that serve to keep membrane structure intact but also have the ability to trigger signaling cascades. CNL have been shown to be efficacious as a treatment in several tumor models including a successful phase 1 clinical trial in solid tumors. Strikingly, we observed that in vitro CNL is very efficacious against AR-negative PCa cells, which represent the later stages of the disease. However, in AR-positive this efficacy was reduced, but improved upon combination treatment with AR inhibitors. By combining CNL with Enzalutamide (AR antagonist) or Abiraterone acetate (testosterone synthesis inhibitor) we observed enhanced efficacy and synergistic effects. We then sought to understand the molecular mechanism underlying this synergistic effect. We observed that by blocking AR, cells were able to synthesize sphingolipids de novo and adding CNL further magnified this effect. We then looked at the expression of the key enzymes in this synthesis pathway and determined that AR negatively regulates an important subunit (SPTSSB) and this negative regulation hinders the efficacy of CNL. In conclusion, we have not only found a promising therapeutic for patients that currently have no treatment options, but also a novel molecular pathway regulated by AR in prostate cells.

Citation Format: Pedro Costa-Pinheiro, Abigail Heher, Michael Raymond, Kasey Jividen, Todd Fox, Mark Kester. Ceramide nanoliposomes a novel therapeutic option for androgen receptor negative prostate cancer [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 2079.
Abstract 2080: Tissue-specific tumorigenesis in multiple endocrine neoplasia type I
Authors: Gardiner Juliet C. , Libutti Steven K.
Published: September 2020

While a germline heterozygous mutation in the Multiple Endocrine Neoplasia type 1 (MEN1) gene predisposes tumor formation in specific tissues such as the endocrine pancreas, parathyroid glands and anterior pituitary, this tissue-specific tumorigenesis is not dependent on MEN1 mutations alone. In fact, a homozygous deletion of Men1 in mouse pancreatic exocrine tissue does not result in tumor formation, suggesting a tissue-specific mechanism. Loss of menin activates a menin-interacting protein retinoblastoma-binding-protein 5 (RBBP5). Since RBBP5 transcriptionally regulates DNA methyltransferase 1 (DNMT1), this causes global DNA hypermethylation and subsequent tumorigenesis in MEN1-target endocrine tissues. We hypothesize that while RBBP5 is ubiquitously expressed, it exclusively binds to the DNMT1 promoter in MEN1-target-tissues through its recruitment by tissue-specific factors. Using chromatin immunoprecipitation, we demonstrated that Rbbp5 is bound to the Dnmt1 promoter in MEN1-target-tissues, while not in non-target tissues. Following a high-throughput genome-wide approach, we identified two candidate factors that may recruit Rbbp5 to the Dnmt1 promoter. Immunohistochemistry showed MEN1-target-tissue-specific expression of these target factors. Co-immunoprecipitation revealed MEN1-target-tissue-specific binding of Rbbp5 to the factors. In conclusion, Rbbp5 binds the Dnmt1 promoter in MEN1-target-tissues and we have identified candidates for Rbbp5 recruitment to the Dnmt1 promoter that must be tested further to determine their role in the observed tissue specificity of MEN1-related tumorigenesis.

Citation Format: Juliet C. Gardiner, Steven K. Libutti. Tissue-specific tumorigenesis in multiple endocrine neoplasia type I [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 2080.