bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 5749: The association between physical health-related quality of life, physical functioning and risk of contralateral breast cancer
Authors: Mukand Nita , Nabulsi Nadia , Alobaidi Ali , Asfaw Alemseged , Chiu Brian C. , Ko Naomi Y. , Calip Gregory S.
Published: September 2020

Background: Physical limitations and disability among older cancer patients can lead to suboptimal treatment and surveillance for secondary cancers. Our objective was to evaluate the effects of poor physical health-related quality of life (PQOL) and physical functioning (PF) on contralateral breast cancer (CBC) risk among older women diagnosed with unilateral breast cancer (UBC).

Methods: We performed a nested case-control study within a cohort from the Surveillance, Epidemiology and End Results Medicare Health Outcomes Survey (MHOS) database. Women were required to have first primary UBC without prophylactic contralateral mastectomy. Among 2,938 women ages 65 years and older with stages I-III UBC between 1997 and 2011, we identified 100 subsequent CBC cases and 915 controls using incidence density sampling without replacement matched on age, race, and quarter-year of diagnosis. PQOL and PF were determined from survey responses to the Medical Outcomes Trust Short Form 36 component scores. Conditional logistic regression models were used to estimate relative risks (RR) and 95% confidence intervals (CI) for metachronous CBC.

Results: Cases and controls were similar with respect to comorbidities, stage, surgery and radiation treatments but differed by hormone receptor status (ER/PR-negative, cases 23% and controls 11%). Cases had lower mean PQOL (-1.8; 95% CI -4.3, 0.7) and PF (-2.2, 95% CI -4.9, 0.5) component scores, but these differences were not statistically significant. In multivariable models, estimates suggest increased CBC risk for women in the lowest quartile of PQOL compared to those in the upper quartile (RR=1.8; 95% CI 0.8, 4.3). Compared to women in the upper quartile of physical functioning scores, women in the lower three quartiles had a 2.6-fold (95% CI 1.2, 5.9) increased risk of CBC.

Conclusions: Our findings indicate that low physical health-related quality of life is common among older women diagnosed with breast cancer, and poor physical functioning is related to risk of CBC. Efforts to understand and minimize declines in physical functioning post-breast cancer diagnosis may help optimize treatment strategies to reduce the risk of this adverse outcome.

Citation Format: Nita Mukand, Nadia Nabulsi, Ali Alobaidi, Alemseged Asfaw, Brian C. Chiu, Naomi Y. Ko, Gregory S. Calip. The association between physical health-related quality of life, physical functioning and risk of contralateral 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 5749.
Abstract 575: Disulfiram plus copper synergizes with etoposide for the treatment of Merkel cell carcinoma
Authors: Hill Natasha Tremayne , Gelb Tara , Urban Dan , Kellenberger Tyler , Hall Matthew , Brownell Isaac
Published: September 2020

Merkel cell carcinoma (MCC) is an aggressive neuroendocrine skin cancer with limited treatment options. Currently two immunotherapies are approved for the treatment of MCC, the PD-L1 inhibitor avelumab and the PD-1 inhibitor pembrolizumab. Unfortunately, these treatments only have durable benefit for less than half of patients that can be treated with immunotherapy. Therefore, new and effective treatments are needed for MCC. To address this, we conducted a high-throughput drug screening of ~4,000 small molecules. Our drug screen identified disulfiram (DSF), an aldehyde dehydrogenase inhibitor used in the treatment of alcoholism, as an agent that selectively reduced MCC cell viability. Recent studies suggest that DSF complexed with copper can have anti-cancer effects. Consistent with this, the addition copper at physiological levels increased the potency of DSF in MCC cells lines. Next, we demonstrated that disulfiram combined with copper synergized with the topoisomerase II inhibitor etoposide, lowering the effective dose of etoposide required to reduce MCC cell viability. Mechanistically, combining DSF, copper and etoposide was cytotoxic but did not induce apoptosis in MCC cell lines. This combination increased the formation of double stranded DNA breaks while disulfiram plus copper induced autophagy, which could mechanistically be an indication of immunogenic cell death signaling. Taken together, our data suggest that disulfiram combined with copper and etoposide could be repurposed for the effective treatment of advanced MCC. One strong advantage of this combination is that all agents can be given orally and at dosages with minimal adverse effects.

Citation Format: Natasha Tremayne Hill, Tara Gelb, Dan Urban, Tyler Kellenberger, Matthew Hall, Isaac Brownell. Disulfiram plus copper synergizes with etoposide for the treatment of Merkel cell carcinoma [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 575.
Abstract 5779: The association of instrument assisted deliveries and the development of childhood brain tumors: A matched case control study
Authors: Yeh Karen , Hansen Johnni , Heck Julia E.
Published: September 2020

Background: Pediatric brain tumors are the second most common type of childhood cancer and have the highest mortality rate among all pediatric cancer types. New information on potentially preventative measures would be of great value. Previous studies have suggested that instrument-assisted delivery (forceps and vacuum) may be associated with an increased risk for childhood brain tumors. The goal of this study was to determine if there was an association of exposure to instrument-assisted deliveries with childhood brain tumors in Denmark. We additionally examined risk with emergency or planned cesarean section.

Methods: This was a matched case-control study with childhood brain tumor cases in Denmark diagnosed from 1978-2013. Cases were identified from the Danish Cancer Registry. Birth outcomes, maternal procedures and covariates were obtained from the Danish Medical Births Register and the nationwide Hospital Register. A total of 3,698 brain tumor cases were recruited and 25 controls were matched to each case based on child's sex and birth year (N=89,554). We used conditional logistic regression to determine associations of delivery instruments types with various childhood brain tumors.

Results: Compared to children birthed by spontaneous vaginal delivery, children who later developed ependymomas (N=136) had a greater likelihood of having been delivered by vacuum assisted deliveries (OR=1.69, 95% CI 1.01-2.83). An overall increased risk for cesarean section with any CNS tumor (OR= 1.20, 95% CI 1.06-1.36) dropped to 1.10 when we limited the age range to 4 or older (N=1,087). This suggests no clear increased risk for cancer with cesarean section, as there is a possibility that the CNS tumor was present before birth and influenced a larger head size, thus requiring a cesarean section. Planned cesarean and emergency cesarean section were not related to risk increases. While the use of forceps was rare in this population (1.2% in controls), we could not confirm previously reported associations with astrocytoma (OR=0.84), though there was a weak increase for ependymoma with wide confidence intervals (OR=2.69, 95% CI 0.77, 9.38).

Conclusions: Based on objective data, the findings in our study suggest that there might be an association between vacuum assisted deliveries and ependymomas. Our data did not support a strong association of childhood brain tumors with cesarean sections.

Citation Format: Karen Yeh, Johnni Hansen, Julia E. Heck. The association of instrument assisted deliveries and the development of childhood brain tumors: A matched case control study [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 5779.
Abstract 578: Pharmacokinetic proprieties of a locked nucleic acid oligonucleotide targeting miR-221
Authors: Di Martino Maria Teresa
Published: September 2020

MiR-221 is overexpressed in several malignancies where it promotes tumor growth and survival by interfering with gene transcripts, including p27Kip1, PUMA, PTEN, and p57Kip2. We previously demonstrated that a novel 13-mer miR-221 inhibitor (LNA-i-miR-221) exerts antitumor activity against human cancer with a pilot favorable pharmacokinetics and safety profile in mice and non-naive monkeys. Next we performed and here report a non-GLP/GLP dose-finding investigation of LNA-i-miR-221 in Sprague Dawley rats. The safety of the intravenous dose (125 mg/kg/day) for four consecutive days, two treatment cycles, was investigated by a first non-GLP study. Toxicokinetics profile of LNA-i-miR-221 was next explored in a GLP study at three different doses (5, 12.5 and 125 mg/kg/day). Slight changes in blood parameters and histological findings in kidney were observed at the highest dose. These effects were reversible and consistent with in vivo ASO class effect. Based on these findings the NOAEL was established at 5 mg/kg/day. The plasma exposure of LNA-i-miR-221, based on C0 and AUC, suggested no differential sex effect. Slight accumulation occurred between cycles one and two but was not observed after four consecutive administrations. These findings demonstrate a safety profile of LNA-i-miR-221 in Sprague Dawley rats and provide a reference translational framework and path for the development of other LNA miR inhibitors in Phase I clinical study. In addition to understand the pharmacokinetics properties of this new agent, including unbound/total clearance, we investigated the LNA-i-miR-221 protein binding in three different species including rat (Sprague Dawley), monkey (Macaca fascicularis) and human. To this aim, we generated a suitable ultrafiltration method to study the binding of LNA-i-miR-221 to plasma proteins. We identified that the fraction of LNA-i-miR-221 (at concentration of 1 and 10 µM) bound to rat, monkey and human plasma proteins is high and ranges from 98.2 to 99.05%. This high protein binding of LNA-i-miR-221 to plasma proteins in all the species tested translates into a pharmacokinetic advantage by preventing rapid renal clearance. The integration of these results into multiple allometric interspecies scaling methods have been then used to draw inferences about LNA-i-miR-221 pharmacokinetics in humans, therefore providing a framework for definition of safe starting and escalation doses toward a first-in-human clinical trial of LNA-i-miR-221.

This work was supported by the Italian Association for Cancer Research (AIRC), PI: PT. “Special Program Molecular Clinical Oncology - 5 per mille" n. 9980, 2010/15 and its Extension Program 2016/17 n.9980.

Citation Format: Maria Teresa Di Martino. Pharmacokinetic proprieties of a locked nucleic acid oligonucleotide targeting miR-221 [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 578.
Abstract 5811: Combined inhibition of CDK2 and CDK4/6 overcomes acquired resistance to CDK4/6 inhibitors in breast cancer via RB-independent pathway
Authors: Pandey Kamal
Published: September 2020

Objective: FDA-approved CDK4/6 inhibitors (palbociclib, ribociclib and abemaciclib) are widely used to treat metastatic hormone receptor-positive (HR+) breast cancer. Despite the excellent disease control with CDK4/6 inhibitors, acquired resistance emerges in almost all cases. The strategies to combat the resistance are not yet defined. We investigated therapeutic strategies as well as mechanisms of resistance to CDK4/6 inhibitors in breast cancer.

Methods: Palbociclib resistant cells (MCF7-PR and T47D-PR) were generated from the parental MCF and T47D cell lines by treating them with gradually increasing concentration of palbociclib for over 9 months. Cell viability assay, cell cycle, and western blot were performed to confirm the acquired resistance. Microarray analyses were carried out to identify altered gene expression. We validated the overexpressed genes by qRT-PCR and western blot and further confirmed the significant inhibition by CDK2 siRNA in combination with palbociclib both in vitro and in vivo.

Results: Palbociclib-resistant MCF7 and T47D cells had about 10 fold higher half maximal inhibitory concentration (IC50), compared with parental cells. Morphological changes and alteration in EMT markers were observed in resistant cells. Loss of RB and overexpression of cyclin E1 confirmed that the cells gained resistance. Overexpression of C-MYC was observed in resistant cells compared to sensitive counterparts. Furthermore, from analysis of pleural effusion samples from HR+ breast cancer patients, we confirmed again that loss of RB and overexpression of cyclin E are significantly correlated with resistance to CDK4/6 inhibitors. Mechanistically, we found that, cyclin E-CDK2 mediated phosphorylation of C-MYC was responsible for suppressing C-MYC induced senescence. To overcome CDK4/6 inhibitor resistance, combined inhibition of CDK2 and CDK4/6 showed a synergistic effect in palbociclib-resistant in vitro and in vivo model. Further, combination-treated group showed significantly higher β-galactosidase expression compared to no- treatment control or palbociclib alone treated group.

Conclusion: The synergistic anti-proliferative effect of the combined inhibition of CDK2 and CDK4/6 overcame acquired resistance to CDK4/6 inhibitors via RB-independent pathway, that is, suppressing C-MYC. These findings could pave the way for the development of next generation CDK2 inhibitor in CDK4/6 inhibitor-resistant breast cancer, which is characterized by overexpressed cyclin E and C-MYC.

Keywords: CDK4/6, hormone receptor-positive breast cancer, drug resistance

Citation Format: Kamal Pandey. Combined inhibition of CDK2 and CDK4/6 overcomes acquired resistance to CDK4/6 inhibitors in breast cancer via RB-independent pathway [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 5811.
Abstract 5828: Effect of Roscovitine and mifepristone in luminal breast cancer cells
Authors: Vottero Lucía , Lanari Claudia , Fabris Victoria T.
Published: September 2020

The cyclin dependent kinase (CDK)4/6 inhibitors have been recently approved in combination with endocrine therapy for luminal breast cancer treatment. On the other hand, the use of CDK2 inhibitors, such as Roscovitine, appears as a therapeutic alternative to overcome the acquisition of resistance to CDK4/6 inhibitors. However, there are few clinical trials using CDK2 inhibitors for breast cancer treatment. Most of the reports on the effects of Roscovitine were performed in MCF-7 or MDA-MB-231 cells. The aim of this work was to evaluate the effect of Roscovitine on cell proliferation in T47D human breast cancer cells which express both progesterone receptor (PR) isoforms PRA and PRB, and in the T47D-YA and T47D-YB cell lines expressing only PRA or PRB, respectively. We have previously demonstrated that cells overexpressing PRB showed higher levels of cyclin A as compared with those overexpressing PRA, thus we hypothesized that they would be more sensitive to CDK2 inhibitors. Roscovitine inhibited cell proliferation in a dose dependent manner similarly in both MCF-7 cells (used as positive control) and in T47D cells, with IC50 of 11.99 µM and 11.93 µM respectively. In addition, Roscovitine inhibited cell proliferation induced by estrogen treatment in both cell lines (p<0.01); however the percentage of inhibition was higher in MCF-7 compared with T47D cells (70% versus 50%, respectively; p<0.05). Roscovitine also inhibited cell proliferation induced by the fibroblast growth factor FGF2 in T47D cells (Roscovitine 2 µM p<0.001 and 5 µM p<0.05). Whereas both T47D-YA and -YB cells were similarly inhibited by Roscovitine, only in T47D-YA cells the combination of the antiprogestin mifepristone (MFP; 10 nM) and Roscovitine 1 µM in the presence of FGF2 induced a higher inhibitory effect than MFP or Roscovitine single treatments (p<0.01). We conclude that CDK2 inhibitors may be an option for luminal breast cancer treatment independent of the levels of cyclin A, and that they might be used in combination with antiprogestins only in breast cancer cells overexpressing PRA isoform.

Citation Format: Lucía Vottero, Claudia Lanari, Victoria T. Fabris. Effect of Roscovitine and mifepristone in luminal breast cancer cells [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 5828.
Abstract 5833: Senescence is a central response to chemotherapy in ovarian cancer
Authors: Skulimowski Michael , Calvo-Gonzales Llilians , Cheng Shuofei , Clément Isabelle , Portelance Lise , Zhan Yu , Carmona Euridice , de Ladurantaye Manon , Lafontaine Julie , Rahimi Kurosh , Provencher Diane , Mes-Masson Anne-Marie , Rodier Francis
Published: September 2020

High-grade serous ovarian carcinoma (HGSOC) commonly responds to initial therapy, but this response is rarely durable. Understanding the cell fate decisions taken by HGSOC cells in response to treatment could guide new therapeutic opportunities. Here, we find that more than 90% of tissue-derived primary HGSOC cultures, reflecting the original disease, retain the capacity to undergo stress-induced cellular senescence and primarily undergo therapy-induced senescence (TIS) in response to first-line carboplatin/taxol chemotherapy. HGSOC-TIS displays senescence-associated hallmarks, including a stable proliferation arrest, increased p16INK4A expression, persistent DNA damage, an inflammatory secretome, and senolytic sensitivity, suggesting new avenues for selective pharmacological manipulation of these cells. Comparison of pre- and post-chemotherapy patient HGSOC tissue samples revealed changes in physio-pathological senescence biomarkers supporting the occurrence of post-treatment TIS. Whether cell senescence induced by cancer therapy is beneficial or detrimental to treatment outcomes remains unknown. We find that patients with stronger TIS biomarkers in post-chemotherapy tissues have a more favorale 5-year survival, suggesting that the induction of senescence in HGSOC cells accounts, at least in part, for beneficial responses to treatment. Given that HGSOC cells almost universally retain the capacity to undergo senescence and that senescence appears beneficial in this context, senescence-centric therapeutic avenues should be further explored.

Citation Format: Michael Skulimowski, Llilians Calvo-Gonzales, Shuofei Cheng, Isabelle Clément, Lise Portelance, Yu Zhan, Euridice Carmona, Manon de Ladurantaye, Julie Lafontaine, Kurosh Rahimi, Diane Provencher, Anne-Marie Mes-Masson, Francis Rodier. Senescence is a central response to chemotherapy in ovarian 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 5833.
Abstract 5838: RNA methylation regulates autophagy via unfolded protein response in cancers
Authors: Subbarayalu Panneerdoss , Yadav Pooja , Rao Manjeet
Published: September 2020

N6-methyladenosine (m6A) RNA methylation is a dynamic, reversible and most abundant epitranscriptomic modification found on mRNA and long-non coding RNAs. M6A is regulated by methyl transferases (writes m6A), demethylases (erases m6A) and read by specific RNA binding proteins known as m6A readers that can modulate the fate of specific transcript. Recent studies have suggested that RNA methylation affects several fundamental cellular and molecular functions including mRNA splicing, stability, export, stem cell fate, circadian rhythms, DNA repair and cell survival. In addition, we and others have shown that RNA methylation plays an important role in tumor growth and progression. Here, we discovered that m6A may regulate tumorigenesis by regulating autophagy in cancer cells. Our results revealed that altering the levels of m6A methylation led to increased levels of LC3, which is a universal marker for autophagy. In addition, autophagy initiation protein ULK1 and other autophagy complex proteins including ATG5, ATG12, ATG16L1, and LAMP1 levels were significantly increased in cells with altered m6A methylation. Importantly, we discovered that change in m6A levels by altering the RNA demethylase protein induced the unfolded protein response (UPR) pathway, which is a known activator of autophagy. To understand the molecular mechanism of autophagy induction, we looked into three branches of UPR pathways and discovered that protein kinase RNA like kinase (PERK) UPR signaling pathway is highly activated in ALKBH5 depleted cancer cells and might regulate autophagy induction and cancer cell survival. In conclusion, our study is the first investigation to show that RNA methylation plays an important role in cancer growth by regulating autophagy via UPR.

Citation Format: Panneerdoss Subbarayalu, Pooja Yadav, Manjeet Rao. RNA methylation regulates autophagy via unfolded protein response in cancers [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 5838.
Abstract 5843: XBP1 regulates the expression of cell cycle associated genes in ERα positive breast cancer cells
Authors: Barua David , Sultana Afrin , Islam Md Nahidul , Gupta Ananya , Gupta Sanjeev
Published: September 2020

Estrogen receptor α (ERα)-positive breast cancer is a heterogeneous disease with distinct molecular features. Over the time of treatment, endocrine resistance develops in these types of cancers which is major challenge in recent times and finding a better treatment options against these resistant cancers is urgent. Several studies have suggested the association of XBP1 in therapy resistance in ERα-positive breast cancers. Indeed, XBP1 physically interacts with ER and activates ER-dependent transcription in a ligand-independent manner. Moreover, overexpression of XBP1 in ERα-positive breast cancer cells confers estrogen independent growth and reduced sensitivity to anti-estrogen. Despite growing evidence about the involvement of XBP1 in ERα-positive breast cancer, molecular targets of XBP1 is poorly understood. The aim of current study is to identify the XBP1-regulated targets in ERα-positive breast cancer cells. XBP1 deficient sub-clones in MCF7 cells were generated by using CRISPR-CAS9 mediated gene knockout strategy. Cell viability and anti-estrogen sensitivity were determined by MTS assay, cell proliferation was evaluated by colony formation assay, cell death was determined by flow cytometry. XBP1-regulated genes were identified by analysing transcriptomic data from control and XBP1-knockdown T47D cells (GSE49955). Relative expression of genes were analysed by qPCR. RRM2 overexpression clones were generated by transfecting RRM2 vector using nucleofector. Deficiency of XBP1 in MCF7 cells showed decreased growth and proliferation as compared to control MCF7 cells. Deletion of XBP1 in MCF7 cells demonstrated compromised E2-mediated cell growth and reduced activation of E2-dependent genes. Moreover, XBP1 deficiency in MCF7 cells increases sensitivity towards anti-estrogens including tamoxifen and fulvestrant. Expression of cell cycle associated genes RRM2, CDC6 and TOP2A were found significantly reduced in all ERα-positive breast cancer cell lines with compromised function of XBP1. RRM2, CDC6 and TOP2A have been previously reported as direct targets of XBP1 in other cell types (i.e., muscle, pancreatic β-cell, and plasma cell) and helper T-cells. Furthermore, overexpression of RRM2 in XBP1 deficient MCF7 sub-clones rescued the cell growth and proliferation same as control MCF7 clones. Therefore, this study has revealed XBP1 regulated new targets in ERα-positive breast cancer cells which could be instrumental in providing new insights for better therapeutic potential in this context.

Citation Format: David Barua, Afrin Sultana, Md Nahidul Islam, Ananya Gupta, Sanjeev Gupta. XBP1 regulates the expression of cell cycle associated genes in ERα positive breast cancer cells [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 5843.
Abstract 5857: Molecular characterization of response to interferon alpha in sensitive and resistant bladder cancer models
Authors: Osterhout Robin , Green Jennifer , McDonnell Scott , Klova Amy , Kamal Adeela
Published: September 2020

Background:

Over 70% of patients newly diagnosed with bladder cancer will present with non-muscle invasive disease (NMIBC). The standard of care treatment to prevent recurrence and progression is tumor resection followed by Bacillus Calmette-Guerin (BCG). While this treatment regimen is effective for many patients, a significant fraction become resistant over time. Adenoviral-delivered IFNα gene therapy is emerging as a safe and efficacious treatment for BCG-refractory NMIBC. IFNα is a type 1 interferon that mediates complex tumor-immune interactions, and also has direct cytotoxic effect on tumors. While the mechanisms of IFNα have been extensively studied, it is unclear which of these mechanisms are most relevant for driving therapeutic response. It is also poorly understood why some tumors are sensitive to the direct cytotoxic effects of IFNα and others are resistant.

Methods:

Here, we investigate the molecular mechanisms of tumor-intrinsic sensitivity and resistance to IFNα. We characterized response of a panel of bladder cancer cell lines to treatment with IFNα, and performed concomitant gene expression profiling to identify molecular features and pathways associated with response and sensitivity. These features were then compared across responsive and non-responsive cancer cell line models from other tissues of origin including skin, pancreas, liver and lung.

Results/Conclusions:

Several bladder cancer models exhibited a dose-dependent cytotoxic response to IFNα treatments, while others were resistant to these effects. Genomic and mRNA features associated with IFNα sensitivity/resistance were identified. Pan-cancer cell line analysis identified conserved and putative tissue-specific differences in IFNα downstream signaling genes in resistant vs sensitive cell lines. These features are being evaluated and will inform future investigation of the mechanism of IFNα anti-tumor activity in patients.

Citation Format: Robin Osterhout, Jennifer Green, Scott McDonnell, Amy Klova, Adeela Kamal. Molecular characterization of response to interferon alpha in sensitive and resistant bladder cancer models [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 5857.
Abstract 5859: Genomic correlates of response to immune checkpoint inhibitors in advanced head and neck squamous cell carcinoma
Authors: Patel Nisarg A. , Vokes Natalie I. , Elmarakeby Haitham , Hanna Glenn J. , Van Allen Eliezer M.
Published: September 2020

Background:

Objective response rates for patients with advanced head and neck squamous cell carcinoma (HNSCC) receiving PD-1/L1 immune checkpoint inhibitors (ICI) without chemotherapy remain under 25%. Some studies suggest that HNSCC patients with human papillomavirus (HPV)-associated disease and high tumor mutational burden (TMB) derive greater benefit, although these findings do not yet guide patient selection. We hypothesized that uniform genomic analysis of a larger cohort may help place the predictive value of TMB in a broader biological context and identify more robust predictors of response.

Methods:

274 patients with biopsy-proven HNSCC treated with ICI at our institution from June 2014 to September 2018 were identified. Following targeted massively parallel sequencing, single nucleotide variant calling, and quality control measures, 127 samples were available for analysis. Clinical records were reviewed to determine radiographic response and overall survival. Responders included complete or partial responders by RECIST v1.1. Nonresponders included those with progressive or stable disease. We evaluated associations between genomic features and response using standard statistical methods.

Results:

TMB for the entire cohort was significantly higher among responders (p = 0.01, Fisher's); however, it had poor predictive power (AUROC = 0.68). Among the entire cohort, somatic mutations in NOTCH1 were enriched in responders (12/26 R, 17/101 NR, p = 0.003). After correcting for TMB, NOTCH1 remained associated with complete or partial response (p < 0.05, logistic regression). After adjusting for mutations in NOTCH1, no significant difference in TMB was observed between responders and nonresponders (p > 0.05, logistic regression). Among HPV-negative responders, somatic mutations in CDK12, a transcription-associated kinase whose loss is associated with genomic instability, neoantigen burden, and T cell infiltration, were enriched (3/26 R, 0/101 NR, p = 0.008, Fisher's).

Conclusion:

Through uniform genomic analysis of the largest ICI-treated HNSCC cohort to-date, we validated prior findings regarding the significance of TMB and NOTCH1 as correlates of response for ICI in HNSCC. We also show that TMB alone is insufficient as a predictor of response. We identify CDK12 as a variant with a mechanistic relationship to tumor immunology as a possible correlate of response in HPV-negative patients, which warrants further investigation.

Citation Format: Nisarg A. Patel, Natalie I. Vokes, Haitham Elmarakeby, Glenn J. Hanna, Eliezer M. Van Allen. Genomic correlates of response to immune checkpoint inhibitors in advanced head and neck squamous cell carcinoma [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 5859.
Abstract 5866: SCAR (Selective CRISPR Antigen Removal) vector system expands cancer immunology discovery with in vivo functional genomics
Authors: Dubrot Juan , Lane-Reticker Sarah Kate , Kessler Emily , Wolfe Clara , Mahapatra Animesh , Du Peter , Manguso Robert T.
Published: September 2020

The ability to make rapid genetic alterations to tumor cells with CRISPR for screens and single-gene studies has been transformative for studying cancer biology. Recently, we and others have used CRISPR in murine tumor models in vivo to identify targets and resistance mechanisms for immunotherapy. However, the use of these techniques in immunocompetent mice is limited by endogenous immune recognition of CRISPR components such as Cas9. Here we report the design of a screening-compatible lentiviral vector system which allows selective CRISPR antigen removal (SCAR) from tumor cells before they are implanted in vivo. The SCAR system enables highly efficient genome engineering and reverses CD8+ T cell-mediated rejection of CRISPR modified tumor cells in vivo. Using this technology, we conducted a pooled, in vivo screen designed to probe tumor-immune interactions in the highly immunogenic CT26 colon carcinoma model and discovered that these tumors require intact interferon signaling to evade immune destruction. The SCAR system enables the study of tumor-immune interactions in any cancer model and can be more broadly applied to generate non-immunogenic lentivirally-engineered cells.

Citation Format: Juan Dubrot, Sarah Kate Lane-Reticker, Emily Kessler, Clara Wolfe, Animesh Mahapatra, Peter Du, Robert T. Manguso. SCAR (Selective CRISPR Antigen Removal) vector system expands cancer immunology discovery with in vivo functional genomics [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 5866.
Abstract 5882: Genomic correlates of differential response to EGFR-directed tyrosine kinase inhibitors
Authors: Vokes Natalie , Nguyen Tom , Lydon Christine , Chambers Emily , Sholl Lynette , Nishino Mizuki , Van Allen Eliezer , Janne Pasi
Published: September 2020

Background: Oncogenic mutations in EGFR are powerful biomarkers of response to EGFR tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer (NSCLC). However, there remains significant heterogeneity in duration of response to therapy and overall survival. TP53 mutations have been linked with worse outcomes, thought to be due to increased likelihood of small cell transformation.

Methods: We identified NSCLC patients at our institution with sensitizing oncogenic EGFR mutations who had been treated with EGFR TKI(s) and who had at least one tumor specimen profiled via targeted next generation sequencing (OncoPanel). Progression free survival (PFS) on first-line EGFR TKI, overall survival (OS), and resistance mechanism were assessed. Patients were defined as TP53 mutant positive (TP53+) or wild type (TP53-). Pathogenic TP53 mutations were identified and associated with outcome and resistance mechanism.

Results: We identified 270 patients for inclusion in our cohort. 70% were female (190/270), 60% were never smokers (163/270), and median age was 62 (range 29-93). Sensitizing EGFR mutations were predominantly exon 19 deletion (51%, 138/270) or L858R (38%, 103/270). 94% of patients were treated with first-line erlotinib (253/270), and 30% received second-line osimertinib (82/270). TP53+ patients were as likely to achieve objective radiographic response as TP53- (p=0.615), but had shorter PFS (HR 1.56, CI 1.1-2.2, p=0.011). TP53+ patients were no more likely to develop SCLC transformation (p=0.637). Among patients with T790M as their resistance mechanism, TP53+ patients still had shorter PFS compared to TP53- (HR 1.9, CI 1.2-3, p=0.003). Pre-treatment TP53 mutations were associated with a higher tumor mutational burden (p=0.017) and copy number burden (p=0.0026).

Conclusion: While TP53 mutations associate with shorter PFS, there is no association with baseline TP53 mutation status and small cell transformation, and TP53+ patients also develop the T790M resistance mutation earlier than TP53- patients. Higher mutation and copy number burden in TP53+ patients suggests greater genomic instability and may act as a mechanism of earlier resistance development.

Citation Format: Natalie Vokes, Tom Nguyen, Christine Lydon, Emily Chambers, Lynette Sholl, Mizuki Nishino, Eliezer Van Allen, Pasi Janne. Genomic correlates of differential response to EGFR-directed tyrosine kinase 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 5882.
Abstract 5918: The role of the cell-adhesion molecule Metadherin in inflammatory breast cancer progression
Authors: Ortiz-Soto Gabriela , Suárez-Arroyo Ivette J. , Martínez-Montemayor Michelle M.
Published: September 2020

Inflammatory breast cancer (IBC) is the most lethal form of breast cancer where patients display a lower 5-year survival rate. The lethality of IBC originates from its nature of invading the vascular and lymphatic systems, absence of a tumor mass, and generation of tumor emboli. Currently, the accurate and early diagnosis and the development of effective targeted therapies remains a challenge. Thus, in an attempt to discover potential biomarkers, we characterized the IBC cell surface proteome. Plasma membrane proteins were identified via SILAC and MS quantitative proteomics using the IBC SUM-149 vs. MCF-10A a non-cancerous mammary epithelial cell line. SILAC results showed overexpression of Metadherin (MTDH) in IBC cells (>2.0 FCh) and was validated in IBC tissues and emboli. MTDH is a cell adhesion molecule overexpressed in many cancer types, including breast cancer. MTDH promotes cancer progression by modulating various signaling pathways including NF-kB, which is related to cell survival, proliferation, invasion and metastasis. Thus, the aim of this study is to assess the functional role of MTDH in IBC progression. To elucidate the mechanism of action of MTDH in colony formation and tumor spheroids we silenced MTDH (CRISPR or shRNA) SUM-149 and SUM-190 IBC cells. We assessed the expression of MTDH by immunoblotting and immunofluorescence where we observed reduced MDTH levels. The number of colonies formed in SUM-149 MTDH silenced cells was ~40% lower when compared to non-silenced cells. Tumor spheroids of SUM-149 and SUM-190 MTDH silenced cells were smaller than non-silenced cells. Additionally, MTDH silencing results in a decrease in the phosphorylation of the p65 subunit of NF-kB while no changes are observed in total protein abundance in SUM-149 cells. We can conclude from our preliminary results that MTDH serves as a potential IBC target for IBC progression. This work was supported by NIH NIGMS #GM111171 (MMM), SGRP 2017-00143 (MMM and GOS), NIMHD #MD007583 (MMM), GM103475 (UPR MMM), Title-V-PPOHA #P031M105050, Title-V-Cooperative #P031S130068 from the U.S. Dept. of Education and Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health #P20GM103475 (GOS).

Citation Format: Gabriela Ortiz-Soto, Ivette J. Suárez-Arroyo, Michelle M. Martínez-Montemayor. The role of the cell-adhesion molecule Metadherin in inflammatory breast cancer progression [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 5918.
Abstract 5949: Artesunate influences the transcripts for Eph receptors and ephrin ligands in breast cancer cells
Authors: Zadeh Tanin , Lucero Mariana , Kandpal Raj
Published: September 2020

Purpose: Artesunate (ART), an anti-malarial drug, has been shown to induce apoptosis in breast cancer cells. The current study was conducted to explore the involvement of Eph receptor and ephrin ligand transcript levels in mediating apoptotic functions of ART in three phenotypically distinct breast cell lines. The specific involvement Eph receptors and ephrin ligands in apoptosis may potentially lead to novel approaches for therapeutic intervention of breast cancer.

Methods: We cultured three cell lines that represent non-tumorigenic breast epithelium (MCF10A), non-invasive breast carcinoma (MCF7), and invasive triple negative breast carcinoma (MDA- MB-231) in the presence of varying concentrations of ART. Total RNA was isolated from untreated and ART-treated cell lines, and the relative abundance of Eph receptor and ephrin ligand transcripts was determined by qPCR. The changes in selected transcripts were confirmed by immunocytochemistry and western blot analysis.

Results: Our study revealed that the transcripts corresponding to various Eph receptors and ephrin ligands are differentially expressed in a cell line specific manner in ART-treated cells. Specifically, EphA5 was upregulated and EphB4 was significantly downregulated in MCF10A cells. However, MDA-MB-231 cells were distinguished by upregulation of ephrinA2 and downregulation of EphA7, respectively. MCF7 also showed distinct response to ART treatment. Combinatorial alterations in transcript abundance for a subset of Eph receptors and ephrin ligands are likely to provide meaningful insights in the apoptotic effects of ART in breast cancer cells.

Conclusions: A variety of experiments directly or indirectly support the role of Eph receptors and ephrin ligands in apoptosis of numerous cell types. To our knowledge, there have been no conclusive studies to implicate these molecules in ART-mediated cell death. We have demonstrated cell line-specific alterations in the levels of Eph/ephrin transcripts in cells primed for apoptosis by ART-treatment. Specifically, EphA5, EphA7, EphB4 and ephrin A2 appear to transduce apoptotic signals in ART-treated cells. These observations set the basis for pursuing additional mechanistic investigations to decipher novel mediators of apoptosis in breast cancer cells.

Citation Format: Tanin Zadeh, Mariana Lucero, Raj Kandpal. Artesunate influences the transcripts for Eph receptors and ephrin ligands in breast cancer cells [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 5949.
Abstract 5953: Regulation of androgen receptor stability by nuclear export protein CRM1
Authors: Thomas Naiju , Kumar Rajendra , Topiwala Deven , Boyapati Kavya , Kanacharoen Suthicha , Carducci Michael , Denmeade Samuel , Kachhap Sushant K.
Published: September 2020

Import of ligand-bound androgen receptor (AR) into the nucleus occurs with the help of nuclear importin. Past studies have identified a nuclear export signal (NES) in AR. CRM1 (also called XPO1 or Exportin1) is a well-studied exportin that exports proteins and RNA from the nucleus to the cytoplasm. GTP-bound active Ran, CRM1, and the cargo protein form a ternary complex that is exported through the nuclear pore complex. Previous experimental data indicate that RanGTP plays a vital role in Prostate cancer (PCa) progression. Our analyses further suggest that patients who have overexpression of CRM1 and/or Ran have significantly decreased survival. These results indicate that nucleocytoplasmic transport is essential for prostate cancer progression and inhibiting CRM1 could selectively inhibit cancer cell growth. We demonstrate that CRM1 does not affect the nuclear export of AR protein. However, quite surprisingly, we provide novel evidence that CRM1 binds to AR mRNA and is also required for AR protein stability. Inhibiting CRM1 using CRM1 inhibitor results in a dose-dependent rapid loss of AR and AR-V7 splice variants in PCa cells. This observation opens up an entirely new avenue to therapeutically regulate AR signaling using CRM1 inhibitors.

Citation Format: Naiju Thomas, Rajendra Kumar, Deven Topiwala, Kavya Boyapati, Suthicha Kanacharoen, Michael Carducci, Samuel Denmeade, Sushant K. Kachhap. Regulation of androgen receptor stability by nuclear export protein CRM1 [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 5953.
Abstract 5963: NGS-based murine pan-cancer gene expression panel for immuno-oncology and tumor microenvironment studies
Authors: Chen Xiaobo , Xue Jia , Li Qixiang , Guo Sheng
Published: September 2020

INTRODUCTION: Cancer is a heterogeneous disease and highly related to the immunological system. The significance of fully understanding the interactions between cancer and immunity in cancer therapeutics has been broadly noted, particularly for immunotherapies. Experimental murine models derived from a variety of biological technologies are essential preclinical model systems utilized before clinical studies. Molecular pathology techniques, such as gene expression biomarkers, are widely used to systematically profile and characterize these models. So far, however, there has been no robust and cost-effective assay designed for murine clinical immuno-oncology (I/O) research to characterize tumor-immune interactions at a gene expression level.

METHODS: Marker genes were identified by combining public and in-house reference genomic data for non-tumor bearing mice as well as tumor mouse models. Oligonucleotide-based hybridization/capture techniques analogous to exome sequencing, targeting specific regions are well established on Illumina Novaseq and BGI MGIseq platforms. These methods were applied to the murine I/O panel assay, with accuracy and reproducibility verified across these two sequencing platforms. The results were further qualified using a PCR array platform.

RESULTS: A mouse gene panel involving 1080 genes that encompass surface markers and transcriptomic biomarkers for the immune system, key pathways at the interface of the tumor, tumor microenvironment (TME), and immune response, as well as internal reference genes for data normalization has been established. By combining advanced NGS technologies and specific bioinformatic pipelines, we were able to detect and distinguish various immune and stromal cells involved in the complex interaction between the tumor and its microenvironment, allowing for a multifaceted characterization of disease biology and the interrogation of immune response and evasion. We validated the sensitivity, specificity, and repeatability of the panel by qPCR experiments.

CONCLUSIONS: We have established a murine-I/O NGS panel involving 1080 genes to characterize tumor-immune interactions more efficiently and in a cost-effective manner for preclinical studies. This provides an enhanced insight into the TME, with high-content data that has the potential to translate more effectively to the clinic as well as for early identification of immunotherapy companion diagnostics.

Citation Format: Xiaobo Chen, Jia Xue, Qixiang Li, Sheng Guo. NGS-based murine pan-cancer gene expression panel for immuno-oncology and tumor microenvironment studies [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 5963.
Abstract 5977: Maf1 suppresses hepatocarcinogenesis in mice through inhibition of Akt-mTOR signaling
Authors: Cao Di , Li Xiaoxing , Yang Yang , Zhou Yu-Feng , Zhang Mei-Yin , Zhang Shan-Shan , Ren Qian-Nan , Zhang Hui-Zhong , Zhang Yao-Jun , Mai Shi-Juan , Wang Hui-Yun
Published: September 2020

Maf1 is a transcriptional repressor downstream of mTORC1by inhibiting transcription of lipogenic genes by RNA Pol II and ribosomal/transfer RNA genes by RNA Pol III. We recently showed that Maf1 suppresses the growth of cultured liver cancer cells and xenograft tumors by blocking Akt-mTOR signaling through the tumor suppressor PTEN. However, whether Maf1 has tumor suppressor activity has never been demonstrated in physiologically relevant tumor models. Here, we investigated the role of Maf1 in hepatocarcinogenesis in NRas/Akt- and c-Myc-driven mouse liver cancer models generated by hydrodynamic transfection (HDT). We found that Maf1 or Maf1-4A, a non-phosphorylatable and active form of Maf1, significantly attenuated the development of NRas/Akt-driven liver tumors. On the other hand, while knockdown of Maf1 alone did not cause any discernible abnormality in the mouse liver, down-regulation of Maf1 markedly accelerated c-Myc-induced liver tumor development. At the molecular level, Maf1 strongly suppressed phosphorylation of Akt-mTOR pathway components, including Akt and S6. Conclusions: Maf1 suppresses hepatocarcinogenesis through restraining Akt/mTOR signaling. These new findings provide first in vivo evidence that Maf1 is a liver tumor suppressor.

Citation Format: Di Cao, Xiaoxing Li, Yang Yang, Yu-Feng Zhou, Mei-Yin Zhang, Shan-Shan Zhang, Qian-Nan Ren, Hui-Zhong Zhang, Yao-Jun Zhang, Shi-Juan Mai, Hui-Yun Wang. Maf1 suppresses hepatocarcinogenesis in mice through inhibition of Akt-mTOR signaling [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 5977.