bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 4742: The influence of cellular developmental state on response to therapeutics in glioblastoma
Authors: Nuga Oluwademilade , deCarvalho Ana , Ruden Douglas , Brown Stephen , Datta Indrani , Malta Tathianne
Published: August 2019

Glioblastoma (GBM) is an aggressive tumor treated with ionizing radiation (IR) and temozolomide (TMZ). Here we investigate how developmental state of glioblastoma cells: cancer stem cells (CSC) or differentiated cells, influences cellular response to treatment. Tissue from untreated primary GBM tumors representing diverse genotype were dissociated and cultured in conditions selective for CSCs, which were subsequently differentiated into an astrocytic phenotype by culturing in media supplemented with 2% FBS. Stemness index was evaluated using a machine learning predictive algorithm. Sensitivity of both isogenic CSC and serum differentiated cell (SDC) populations to TMZ and IR was determined by non-linear fitting of dose-response curves, using CellTiterGlo to measure cell viability (n=5) . CSCs and SDCs were then subjected to sub-lethal TMZ, IR (4 Gy), or control treatments, in triplicate. Cells were harvested, and DNA was isolated and Illumina 450k DNA methylation array data was analyzed by using the Methylumi package in R software. RNA was isolated for sequencing, and differentially expressed genes were determined by NOISeq R package. Our results show that GBM CSCs are more vulnerable to both TMZ and IR treatment than the isogenic SDCs. Transcriptome profiling show that IR leads to increase in p53 mediated expression of pro-apoptotic genes such as MDM2, PUMA and BCL2 binding protein relative to control in CSCs. In differentiated cells, IR lead to an increase in WNT signaling, DNA-repair activity and histone modification /remodeling proteins. Enrichment analysis using Fisher’s exact test identified significant enrichment in lipid, fatty acid and metabolic processes as well as receptor tyrosine signaling. Globally, CSCs exhibited a decrease in protein coding genes and increase in regulatory RNA expression. DNA methylation show a global increase in CpG promoter methylation in differentiated cells relative to isogenic stem-like counterparts. We recovered significant differentially methylated probes between treatment groups (Wilcoxon signed rank test) as well as a global increase in CpG promoter methylation in IR treated cells relative to control. These findings underscore the challenge of treating a highly heterogeneous tumor and challenge a strategy of inducing differentiation to increase GBM sensitivity to treatment.

Citation Format: Oluwademilade Nuga, Ana deCarvalho, Douglas Ruden, Stephen Brown, Indrani Datta, Tathianne Malta. The influence of cellular developmental state on response to therapeutics in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4742.
Abstract 476: MEK inhibitors for treatment of oligodendroglioma
Authors: Majd Nazanin , Park Soon Young , Kraatz Marisela Martinez de , Balasubramaniyan Veerakumar , Sandeep Mittal , Hu Jian , Paik Jihye , Groot John de
Published: August 2019

Oligodendroglioma (OD) is defined by the 2016 WHO classification as IDH mutant gliomas with 1p19q co-deletion. Although ODs are sensitive to chemotherapy, they eventually recur leading to functional deficits and ultimately death. CIC gene mutations, located on chromosome 19q are seen in 60% of 1p19q co-deleted OD and have been linked to worse survival. Despite our growing knowledge of the molecular characteristics of OD, all recurrent OD patients are treated similarly mainly using radiation and/or poorly tolerated cytotoxic chemotherapy with modest benefit. There is therefore an urgent unmet medical need to understand the molecular consequence of recurrent mutations in OD in order to improve patient outcomes. CIC gene mutations result in truncated, degraded or non-functional CIC protein, disrupting CIC protein repressor functions. This leads to upregulation of ETS-Pea3 family of transcription factors which are known oncogenes in a variety of solid cancers. MAPK signaling pathway has been shown to directly activate ETS family of proteins in drosophila. However, the link between MAPK signaling, ETS proteins and CIC in OD is elusive. Here, we propose a model of aggressiveness in CIC mutant OD in which these cells are dependent on MAPK axis for activation of their augmented ETS proteins (i.e ETV1, ETV4) and therefore are sensitive to MAPK inhibition. To test our model, we evaluated mRNA and protein expression of ETS family of proteins in CIC mutant and CIC wild-type mouse OD cell lines and show that ETV1 and ETV4 have elevated protein and mRNA expression in CIC mutant OD cells, respectively. Consistent with our hypothesis, two different MEK inhibitors, trametinib and pimasertib, reduce cell viability of OD cell lines with greater reduction in CIC mutant than wild-type cells. As proof of concept, we demonstrate that CIC mutant cells have increased pERK expression when compared with CIC wild-type cells indicating that MAPK pathway is more active in CIC mutant cells. Overall, we were able to show that MEK inhibitors have anti-tumor effects in OD cell lines, with greater sensitivity seen in CIC mutant cells. This work lays the foundation for repurposing the widely clinically used MEK inhibitors for treatment oligodendroglioma patients with CIC mutation.

Citation Format: Nazanin Majd, Soon Young Park, Marisela Martinez de Kraatz, Veerakumar Balasubramaniyan, Mittal Sandeep, Jian Hu, Jihye Paik, John de Groot. MEK inhibitors for treatment of oligodendroglioma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 476.
Abstract 4762: Activation of AXL as a preclinical acquired resistance mechanism against osimertinib treatment in EGFR-mutant non-small cell lung cancer cells
Authors: Namba Kei , Shien Kazuhiko , Takahashi Yuta , Sato Hiroki , Yoshioka Takahiro , Suzawa Ken , Yamamoto Hiromasa , Soh Junichi , Tomida Shuta , Toyooka Shinichi
Published: August 2019

Osimertinib (AZD9291) has an efficacy superior to that of standard EGFR-tyrosine kinase inhibitors for the first-line treatment of EGFR-mutant advanced non-small cell lung cancer (NSCLC) patients. However, patients treated with osimertinib eventually acquire drug resistance, and novel therapeutic strategies to overcome acquired resistance are needed. In clinical or preclinical models, several mechanisms of acquired resistance to osimertinib have been elucidated. However, the acquired resistance mechanisms when osimertinib is initially used for EGFR-mutant NSCLC remain unclear. In this study, we experimentally established acquired osimertinib-resistance cell lines from EGFR-mutant NSCLC cell lines and investigated the molecular profiles of resistant cells to uncover the mechanisms of acquired resistance. Various resistance mechanisms were identified, including the acquisition of MET amplification, EMT induction, and the upregulation of AXL. Using targeted next-generation sequencing with a multi-gene panel, no secondary mutations were detected in our resistant cell lines. Among three MET-amplified cell lines, one cell line was sensitive to a combination of osimertinib and crizotinib. Acquired resistance cell lines derived from H1975 harboring the T790M mutation showed AXL upregulation, and the cell growth of these cell lines was suppressed by a combination of osimertinib and cabozantinib, an inhibitor of multiple tyrosine kinases including AXL, both in vitro and in vivo. Our results suggest that AXL might be a therapeutic target for overcoming acquired resistance to osimertinib.

Citation Format: Kei Namba, Kazuhiko Shien, Yuta Takahashi, Hiroki Sato, Takahiro Yoshioka, Ken Suzawa, Hiromasa Yamamoto, Junichi Soh, Shuta Tomida, Shinichi Toyooka. Activation of AXL as a preclinical acquired resistance mechanism against osimertinib treatment in EGFR-mutant non-small cell lung cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4762.
Abstract 4774: Engineering an oncolytic adenovirus to target CEA in colorectal cancer
Authors: Schaumburg Jessica C.
Published: August 2019

Colorectal cancer is the second leading cause of cancer-related deaths in the United States and the third most commonly diagnosed cancer overall. Screening methods can identify precancerous polyps before they progress, leading to five-year survival rates of 92%. However, if diagnosed in later stages the survival rates decrease to 12%. While treatment options are available for advanced stages, they remain inadequate to affect overall survival. Thus, new therapies are needed to improve treatment outcomes. Oncolytic virotherapy is a unique therapeutic approach in which a virus is genetically modified to target cancer cells while sparing normal tissue. Oncolytic virotherapy takes advantage of the lytic properties of the viral life cycle. These viruses are used replicate inside cancer cells, lyse them and spread to adjacent cells throughout the tumor. The adenovirus is a well-characterized vector that is easily manipulated and produced and is capable of infecting a wide range of cells. However, the endogenous receptor for adenovirus, the Coxsackie and adenovirus receptor (CXADR), is often downregulated in cancers, thus decreasing the ability to selectively infect cancer cells. In this study, an adenovirus was genetically engineered to present the single variable domain (VHH) derived from a camelid heavy chain antibody B2. The B2 antibody recognizes the human carcinoembryonic antigen (CEA), which is often overexpressed in a variety of cancers, including colorectal cancer. Here, the wild-type fiber and knob domain of the adenovirus fiber gene was replaced with a modified T4 fibritin fiber linked to the B2 VHH. To provide for visual tracking of adenovirus infection and biodistribution, a red fluorescent protein (RFP) marker gene was also fused to the capsid protein IX (pIX). This virus was rescued and amplified in the HEK293 F28 packaging cell line with a final round of amplification in HEK293 cells. The virus was purified by CsCl ultracentrifugation and dialysis. The resulting viral stock was titered and characterized for the presence of the modified fiber and knob. Subsequently, the vector was modified to express the human sodium-iodide symporter (NIS) transgene, to allow for noninvasive imaging of the adenovirus uptake and replication as well as radiotherapy using 131I. Further experiments will be completed to confirm viral selectivity for CEA and subsequent lysis of colorectal cancer cells. The results of this study will advance targeting oncolytic adenoviruses to metastatic colorectal cancer.

Note: This abstract was not presented at the meeting.

Citation Format: Jessica C. Schaumburg. Engineering an oncolytic adenovirus to target CEA in colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4774.
Abstract 4780: An antisense-based approach to induce anti-tumorigenic variants of MET receptor
Authors: Rathod Trushar , Cartegni Luca
Published: August 2019

Rational: Aberrant activity of MET receptor, a receptor tyrosine kinase (RTK), is implicated in various forms of cancer. Moreover, functional crosstalk of MET with other RTKs has been reported in tumors and MET has emerged both as a driver and as a primary mechanism of resistance, thus, making MET an attractive target for cancer therapeutics.

Aim: Recently, we have described natural soluble decoy variants for multiple RTKs (sdRKTs), including MET, which can antagonize RTK signaling by ligand sequestration and non-functional dimerization. These isoforms can be generated via intronic polyadenylation (IPA) of RTK’s pre-mRNA in a U1-snRNP dependent manner. Our aim is to activate IPA in MET pre-mRNA using antisense compounds and to increase mRNA variants that express dominant-negative soluble decoy MET (sdMET).

Methods: Identify actionable IPA sites within introns upstream of the transmembrane-coding exon. Express potential sdMET isoforms and characterize their biological properties. For sdMET isoforms with inhibitory functions, anti-sense compounds are utilized to block the upstream U1 binding site, activate IPA sites, and thus increase expression of sdMET variants in MET-dependent cancer cells.

Results: Ectopically expressed sdMET isoforms are secreted into the culture medium. When then added to MET-expressing cells, sdMET variants functioned in a dominant-negative manner over full length MET (FL-MET) and suppressed activation of AKT and MAPK pathways. Moreover, antisense compounds that induce IPA effectively convert oncogenic FL-MET into sdMET variants in multiple cell lines, leading to suppression of downstream pathways and dramatic reduction in cell viability of MET-dependent cells.

Conclusion: Most sdMET isoforms are secreted into extracellular space and have inhibitory function. Our anti-sense approach induces IPA, generates truncated sdMET variants at the expense of FL-MET and efficiently blocks FL-MET’s biological activity.

Citation Format: Trushar Rathod, Luca Cartegni. An antisense-based approach to induce anti-tumorigenic variants of MET receptor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4780.
Abstract 4784: Combination of sorafenib with liver cancer-targeted gene therapy exerts synergistic efficacy against hepatocellular carcinoma
Authors: Dai Huei-Yue , Li Long-Yuan
Published: August 2019

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide. Sorafenib, a multikinase inhibitor, is the first-line target therapy for patients with advanced HCC, but the response rate is low. Thus, development of more effective therapeutics for HCC is needed. Previously we have established a HCC-targeted BikDD gene therapy vector driven by a liver cancer-specific α-fetoprotein promoter/enhancer and transcriptional amplification module. Systemic administration of liposome-loaded HCC-targeted BikDD gene therapy vector effectively suppressed tumor growth and prolonged survival in multiple orthotopic HCC mouse models with no toxicity. Here, we further investigated whether combination of sorafenib with gene therapy could enhance anti-HCC activity. The results showed that combination of BikDD gene therapy with HCC targeted therapeutic agent sorafenib synergistically killed a panel of liver cancer cells but not normal cells in vitro by WST-1 assays and analysis of combination index according to the Chou and Talalay method. Moreover, a low dose of sorafenib combined with BikDD gene therapy augmented tumor inhibition and better mice survival compared with separate treatment alone in xenograft and syngeneic orthotopic HCC mouse models. These results suggest that sorafenib combined with HCC-targeted gene therapy may improve the therapeutic efficacy and may be a potential alternative therapeutics for HCC.

Citation Format: Huei-Yue Dai, Long-Yuan Li. Combination of sorafenib with liver cancer-targeted gene therapy exerts synergistic efficacy against hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4784.
Abstract 4805: Cannabinoid WIN 55,212-2 induces endoplasmic reticulum stress in prostate cancer cells through CB1and CB2receptors
Authors: Roberto Domenica , Klotz Laurence H. , Venkateswaran Vasundara
Published: August 2019

Cannabinoids have demonstrated anticarcinogenic properties in a variety of malignancies, including prostate cancer. WIN 55,212-2 (WIN) is a highly potent synthetic cannabinoid that binds to cannabinoid receptors (CB1 and CB2). We have previously demonstrated that WIN significantly reduces prostate cancer cell proliferation, migration, invasion, induces apoptosis, and arrests cells in the G0/G1 phase through a cannabinoid receptor 2 dependent manner. We also determined that these effects were mediated though a pathway involving cell cycle regulators p27, Cdk4, and pRb. The current study aims to examine the role of endoplasmic reticulum (ER) stress in apoptosis and investigates whether this effect is modulated by WIN and the cannabinoid receptors.

In this study, we evaluated the effect of WIN and CB receptors on ER stress induced apoptosis in established prostate cancer cells (DU145, PC3). Cells were treated with WIN, cannabinoid receptor 1 antagonist (AM251), and cannabinoid receptor 2 antagonist (AM630). Cell proliferation was determined using MTS assays. Quantitative PCR was used to examine changes in expression of ER stress related genes, including CHOP, TRIB3, and ATF4. Western blotting will be completed to determine changes in the expression of apoptotic markers after treatment with WIN and cannabinoid antagonists. Further studies are ongoing looking at the use of the ER stress inhibitor, Salubrinal, to determine whether ER stress is vital for WIN-induced apoptosis.

Our results reveal that treatment with 20μM WIN resulted in a significant reduction in the proliferation of DU145 and PC3 cells after 24 h compared to control (p<0.05). In contrast, treatment with 5μM of either AM251 or AM630 did not result in any significant changes in cell proliferation. Quantitative PCR studies revealed significant upregulation of ER stress genes CHOP, TRIB3 and ATF4 in WIN treated cells (p<0.05). Expression of ER stress genes were significantly downregulated after blocking CB1 and CB2 receptors (p<0.05).

Interim results suggest that WIN has significant antitumoral activity and modulates ER stress-induced apoptosis in prostate cancer cells, thus, may offer a novel therapeutic strategy in the treatment of prostate cancer.

Citation Format: Domenica Roberto, Laurence H. Klotz, Vasundara Venkateswaran. Cannabinoid WIN 55,212-2 induces endoplasmic reticulum stress in prostate cancer cells through CB1and CB2receptors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4805.
Abstract 4807: Pimavanserin suppresses pancreatic tumor growth and resistance to gemcitabine by inhibiting Akt/Gli1 signaling
Authors: Ramachandran Sharavan , Srivastava Sanjay K.
Published: August 2019

Despite major advances in cancer treatment, pancreatic cancer is still incurable and the treatment outcomes are limited. In the current study, we evaluated the anti-cancer effects of pimavanserin tartrate (PVT), a drug used for the treatment of Parkinson’s disease psychosis. Our observations indicated that, PVT significantly suppressed the proliferation of pancreatic cancer cells by inducing apoptosis without exerting any cytotoxic effects in normal human pancreatic ductal epithelial (HPDE-6) cells. The colony forming ability of pancreatic cancer cells was significantly inhibited with PVT treatment. Anti-proliferative and apoptosis inducing effects of PVT were mediated by the inhibition of pAkt (Ser473), Akt, Gli1, Oct-4, SOX-2, NANOG and c-Myc. Akt and Oct-4 inhibition by PVT treatment was further validated by immunofluorescence analysis. Moreover, PVT inhibited the formation of tumorspheres in PANC1 pancreatic cancer cells. Pharmacologically inhibiting or genetically knocking out Akt or Gli1 enhanced the growth suppressive effects of PVT in pancreatic cancer cells. Subsequently, we evaluated the effects of PVT in gemcitabine resistant cells. Our results demonstrated that, PVT reduced the survival of MIAPaCa2 gemcitabine resistant cells in a concentration and time-dependent manner. Further mechanistic analysis indicated that, PVT suppressed the phosphorylation of Akt at Ser 473 and inhibited the expression of Gli1, Oct-4 and c-Myc in MIAPaCa2 gemcitabine resistant cells. Moreover, PVT increased the cleavage of caspase-3 and PARP as an indicator of apoptosis. Oral administration of PVT suppressed BxPC3 tumor xenografts by 50% in athymic nude mice. In another in vivo experiment, PVT treatment inhibited the growth of orthotopically implanted PANC1 tumors by 75%. Chronic administration of PVT did not exhibit any general signs of toxicity or behavioral side effects in mice. Taken together, our results indicate that pancreatic tumor growth suppression by PVT is orchestrated by inhibition of Akt/Gli-1 signaling. Since PVT is already available in the clinic with an established safety profile, our results will accelerate its clinical development for the treatment of patients with pancreatic cancer.

Citation Format: Sharavan Ramachandran, Sanjay K. Srivastava. Pimavanserin suppresses pancreatic tumor growth and resistance to gemcitabine by inhibiting Akt/Gli1 signaling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4807.
Abstract 481: Distinct and overlapping patterns of B-cell growth pathway mutations in CD5-negative B-cell lymphoproliferative disorders
Authors: Shaddy Sophia , Zhao Weiqiang , Tu Huolin , Sisson Brianna , Ren Rongqin , Caruthers Sean , Long Susan , Ru Peng , Epperla Narendranath , Abruzzo Lynne , Maddocks Kami , Jones Dan
Published: August 2019

Low-grade CD5-negative B-cell lymphoproliferative disorders (CD5- LG B-LPD) encompass several entities that often show mutations in different growth regulatory pathways. These include MYD88 (TLR signaling), CD79A/B (BCR complex), CARD11 (CBM signalosome), CXCR4 (chemokine receptor), and NOTCH1/2 and are complemented by KLF2 mutations and BCL6 and MALT1 overexpression. Using targeted, next-generation sequencing (NGS) for 50 B-cell associated growth regulators and epigenetic modifiers (>1000X depth) and cytogenetic/FISH data, we sought to delineate the complementary mutation and gene amplification patterns in 45 consecutive cases of CD5- LG B-LPD. In mutation-negative cases, a 572-gene NGS panel was used to interrogate these pathways more completely. WHO diagnostic criteria were used, without reliance on molecular data, emphasizing morphology features, paraprotein level and type to distinguish lymphoplasmacytic lymphoma (LPL) from marginal zone lymphoma (MZL). As expected, MYD88 L265P mutations were seen in the majority of LPL (11/17, 65%), but also in CD5- chronic lymphocytic leukemia (CLL) (3/9, 33%) and splenic (S) MZL (1/6, 17%) but not in nodal MZL. In 4 LPL cases lacking MYD88 L265P, extra copies of chromosome 3 (BCL6), 6 (IRF4), 12 and/or 18 (MALT1) were seen, with CARD11 mutations in the other 2. NOTCH1/2 mutations were mostly associated with SLL/CLL (3/9, 33%). Mutations in epigenetic regulators (see Table) were seen in the majority of nodal MZL (8/13, 62%) but only few LPL (2/17, 12%) and SMZL (1/6, 17%). CXCR4 inactivating mutations were seen with MYD88 and CD79B mutations and +3/BCL6 alteration. CARD11 mutations were seen with KLF2, MYD88 and NOTCH1/2 mutations. Less common mutations targets included PTPRC and PLCG2 (pre-ibrutinib treatment). The higher rate of mutation in epigenetic regulators (along with loss of KLF2-mediated BCR signaling) supports a distinct pathogenesis for nodal MZL in contrast to other CD5- B-LPD.

Calls per gene in MYD88 negative cases; *TP53, TET2, ASXL1, DNMT3A, BCORCD79BCARD11NOTCH1/2CXCR4KLF2Epigenetic gene set*LPL023000010000000010CD5- CLL000002001001001000001000000001sMZL011010010000000001nMZL000002000022000001010011000101000001000001000001012010000200

Citation Format: Sophia Shaddy, Weiqiang Zhao, Huolin Tu, Brianna Sisson, Rongqin Ren, Sean Caruthers, Susan Long, Peng Ru, Narendranath Epperla, Lynne Abruzzo, Kami Maddocks, Dan Jones. Distinct and overlapping patterns of B-cell growth pathway mutations in CD5-negative B-cell lymphoproliferative disorders [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 481.
Abstract 4826: Enhancement of PTEN activity via peptidomimetics
Authors: Palumbo Emily , Teng Peng , Malaney Prerna , Wilson Jacob , Kearns Fiona , Kemp Michael T. , Tian Zhi , Uversky Vladimir , Allen-Gipson Diane , Chen Yu , Woodcock H. Lee , Cai Jianfeng , Dave Vrushank
Published: August 2019

Compromised PTEN function is associated with multiple cancers. As per the continuum model, variable degree of PTEN inactivation drives distinct cancer phenotypes. Loss of PTEN activity, via genomic/non-genomic mechanisms, leads to enhanced oncogenic PI3K signaling. While kinase inhibitors have proved effective in the clinic, they are increasingly met with off-target effects and therapy-resistance due to compensatory feedback mechanisms. Although PTEN restoration therapy has proved promising in experimental models; implementation of these therapies in the clinic remains challenging. To fill this therapy gap, we have targeted endogenous PTEN for activation via peptidomimetics, mitigating PI3K signaling. Our selected peptidomimetics reduced cell proliferation, migration and cell cycle activity after treatment of non-small cell lung cancer cells expressing endogenous PTEN. Computational studies utilizing PTEN crystal structures revealed a binding site at the interface of the Phosphatase Domain (PD) and C2 Domain (C2D). Induced fit docking indicated that a unique functional group is responsible for peptidomimetic-mediated enhancement of PTEN activity. Molecular dynamics analysis revealed energetically favorable binding of our lead peptidomimetic at the PD/C2D interface, which allosterically modulated the conformation of the active site. Binding of our peptidomimetic altered the active site orientation of PIP3, increasing its binding affinity. In summary, we have developed the first-known direct PTEN activators and analyzed their effects in suppressing oncogenic activities in lung cancer. Refinement of our peptidomimetics, complemented with in vivo studies, will provide a novel clinical rationale to reduce doses of standard therapy and their associated toxicities, decreasing morbidity and mortality observed in the clinic.

Citation Format: Emily Palumbo, Peng Teng, Prerna Malaney, Jacob Wilson, Fiona Kearns, Michael T. Kemp, Zhi Tian, Vladimir Uversky, Diane Allen-Gipson, Yu Chen, H. Lee Woodcock, Jianfeng Cai, Vrushank Dave. Enhancement of PTEN activity via peptidomimetics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4826.
Abstract 4832: Preclinical evaluation of neratinib plus T-DM1 in orthotopic PDX models of HER2-positive breast cancer brain metastases
Authors: Ni Jing , Wang Yanzhi , Diala Irmina , Kabraji Sheheryar , Freedman Rachel , Lin Nancy , Zhao Jean
Published: August 2019

Up to half of patients with metastatic HER2-positive breast cancer will develop brain metastases. Breast cancer brain metastases (BCBM) are a major cause of morbidity and mortality, despite multimodal management including surgery, radiotherapy, and systemic therapies. Therefore, there is an urgent need to develop novel, efficacious therapies. Neratinib is an orally bioavailable, irreversible pan-HER tyrosine kinase inhibitor that is FDA-approved in the extended adjuvant treatment setting for HER2-positive, early breast cancer. Neratinib has only modest activity as a single agent in clinical trials of patients with HER2-positive brain metastases. Though the combination of neratinib and capecitabine results in CNS responses in up to half of patients, patients eventually develop drug resistance, and toxicities have been a concern-thus exploration of alternative neratinib combinations is of significant clinical interest. Ado-trastuzumab emtansine (T-DM1) is an antibody-drug conjugate with reported single-agent activity against HER2-positive BCBM. Here, we used HER2-positive orthotopic patient derived xenograft (PDX) models of BCBM to test if combining neratinib with T-DM1 could improve tumor response. PDX cells are labelled with luciferase to allow tumor growth measurement in vivo. We found that neratinib is able to reduce phosphorylated HER2 in an orthotopic PDX tumor derived from HER2-positive BCBM, indicating that neratinib can cross the BBB and inhibit HER2 activation in BCBM PDX tissues. However, in the HER2-positive DF-BM354 PDX model, single agent neratinib did not block orthotopic tumor growth compared to vehicle control as monitored by bioluminescence measurements. In contrast, combined treatment of neratinib with T-DM1 significantly reduced tumor growth compared to single agent treatment of neratinib or T-DM1 alone at earlier time points. At later time points, the combined treatment is comparable to T-DM1 alone. These data warrant further testing of neratinib alone or in combination with T-DM1 in additional BCBM PDX models to better understand drivers of resistance and susceptibility to HER2-inhibitors in HER2-positive BCBMs. Furthermore, they support the launch of a prospective clinical trial (NCT01494662) to test the efficacy and tolerability of T-DM1 in combination with neratinib in patients with progressive HER2-positive BCBM.

Citation Format: Jing Ni, Yanzhi Wang, Irmina Diala, Sheheryar Kabraji, Rachel Freedman, Nancy Lin, Jean Zhao. Preclinical evaluation of neratinib plus T-DM1 in orthotopic PDX models of HER2-positive breast cancer brain metastases [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4832.
Abstract 4834: Effective treatment of squamous cell carcinoma of the head and neck (HNSCC) using a combined regimen of tipifarnib and cetuximab
Authors: Shu Lihua , Wang Dongsheng , Nannapaneni Sreenivas , Shin Dong M. , Saba Nabil F. , Chen Georgia Z.
Published: August 2019

Background: H-RAS driven carcinogenesis has been reported in many types of cancer including squamous cell carcinoma of the head and neck (HNSCC). The mutation rate of H-RAS in HNSCC is 4 - 8%. Tipifarnib is a potent and highly selective inhibitor of farnesyltransferase (FT). It is known that H-RAS, but not K-RAS and N-RAS, is delocalized into cytoplasm and inactivated by farnesyltransferase inhibitors (FTI), such as tipifarnib. Tipifarnib has demonstrated proof of concept activity in H-RAS mutant HNSCC in an ongoing clinical trial (NCT02383927). In this study, we examined H-RAS associated signaling pathway in HNSCC cell lines and PDX models to see if inhibition of wild-type HRAS signaling could re-sensitize cetuximab resistant cells and tumors to inhibition by cetuximab. UMSCC47 and SCC1-C are both H-RAS wild-type HNSCC cell lines, and SCC1-C is resistant to EGFR targeted therapy.

Methods: In vitro cell growth with and without tipifarnib and/or cetuximab treatments were examined by Sulforhodamine B (SRB) and colony formation assay. Patient derived xenograft (PDX) models were then used to study the efficacy of the tipifarnib treatment as a single agent or in combination with cetuximab. Western blot analyses were performed to verify the effect of these treatments on EGFR/ERK/AKT signaling pathways.

Results: Our results showed that tipifarnib could inhibit HNSCC growth, both in vitro and in the PDX model in a dose-dependent manner (control vs the low dose of tipifarnib, p = 0.02; control vs the high dose of tipifarnib, p = 0.001). However, the combined treatment with cetuximab significantly enhanced tipifarnib efficacy in the H-RAS wild type setting, particularly in the PDX model (control vs tipifarnib, p = 0.123; control vs cetuximab, p = 0.022; control vs the combination, p = 0.010). Western blot analyses showed that neither ERK nor AKT phosphorylation was effectively reduced after a prolonged treatment (48 hours) with tipifarnib alone. However, the addition of cetuximab reduced pERK.

Conclusions: Our study demonstrates that cetuximab enhances the anti-tumor effect of tipifarnib in the H-RAS wild type setting through ERK inhibition. This study supports the rationale for combining tipifarnib with EGFR inhibitors as a possible effective therapeutic approach in HNSCC.

Citation Format: Lihua Shu, Dongsheng Wang, Sreenivas Nannapaneni, Dong M. Shin, Nabil F. Saba, Georgia Z. Chen. Effective treatment of squamous cell carcinoma of the head and neck (HNSCC) using a combined regimen of tipifarnib and cetuximab [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4834.
Abstract 4843: TP53-stabilization with APR-246 enhances antitumor effects of immune checkpoint blockade in preclinical models
Authors: Ghosh Arnab , Michel Judith , Dong Lauren , Suek Nathan , Zhong Hong , Budhu Sadna , Henau Olivier de , Wolchok Jedd , Merghoub Taha
Published: August 2019

An emerging body of literature suggests a role of TP53 pathway in antitumor immunity including antigen presentation and T cell proliferation. Stabilization of TP53 could therefore alter the immune tumor microenvironment, enabling the immune system to target tumor cells more effectively. APR-246 covalently modifies the core domain of cellular TP53 through the alkylation of thiol groups, leading to reactivation of endogenous TP53 activity. To further study the effect of APR-246 on antitumor immunity we used a B16 pre-clinical melanoma mouse model. In vitro treatment of B16 cells with APR-246 caused intracellular accumulation of TP53, leading to increased apoptosis. However, treatment of B16-melanoma bearing mice with APR-246 monotherapy did not result in a statistically significant change in tumor growth or survival. Analyses of the tumor immune microenvironment showed increased immune potentiating M1 polarized tumor-associated macrophages, and Granzyme B activity in CD8+ T cells, suggesting enhanced anti-tumor immunity. Concomitantly, there was increased PD-L1 expression in the macrophages, PD-1 expression on CD8+ T cells, and Foxp3+ Tregs in tumors from APR-246 treated animals. Therefore, we decided to combine anti-PD-1 antibody (RMP-1) to APR-246 treatment in tumor-bearing mice. The combination led to a significant delay in tumor growth (P < 0.001) and improved survival of B16-bearing mice compared to anti-PD1 or APR-246 monotherapies (P < 0.01). Improved responses were also seen in MC38 colorectal cancer-bearing mice (P < 0.01). The anti-tumor effects of APR-246 and anti-PD1 were T cell dependent and abrogated in hosts lacking T cells. Analyses of the tumor immune microenvironment showed that the combination decreases proliferation but increases cytolytic activity of CD8+ T cells compared to anti-PD1 alone. We next studied the effect of combining APR-246 with anti-PD1+ anti-CTLA-4 (9B9). Combination of APR-246 with dual immune checkpoint blockade using anti-PD1 and anti-CTLA-4 showed further tumor growth inhibition in B16-melanoma compared to monotherapies (P < 0.001). Our studies support a role for restoring TP53 in the tumor microenvironment and provide evidence that reactivation of TP53 by APR-246 can enhance anti-tumor immune responses and inhibit tumor growth in preclinical models.

Citation Format: Arnab Ghosh, Judith Michel, Lauren Dong, Nathan Suek, Hong Zhong, Sadna Budhu, Olivier de Henau, Jedd Wolchok, Taha Merghoub. TP53-stabilization with APR-246 enhances antitumor effects of immune checkpoint blockade in preclinical models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4843.
Abstract 4844: A novel anti-TIGIT antibody (YH29143) enhances T cell activity and suppresses Treg cell activity and synergizes with anti-PD-L1 antibody
Authors: Lee Kwang-Hoon
Published: August 2019

TIGIT (T cell immunoreceptor with Ig and ITIM domains) is a T cell coinhibitory receptor, highly expressed on regulatory and memory CD4+, CD8+ T cells and natural killer (NK) cells. TIGIT binding of PVR (poliovirus receptor) on the surface of antigen presenting cells leads to downregulation of CD8+ T cell and NK cell responses in tumors. In this study, we sought to determine the efficacy of TIGIT blockade in antitumor immunity and demonstrate the synergistic effect of treatment with other checkpoint blockade such as anti-PD-L1.

We generated anti-TIGIT monoclonal antibody that binds TIGIT with high affinity and blocks ligand binding. Anti-TIGIT antibody YH29143 was shown to increase T cell activities and suppress Treg cell activities from in vitro cell-based assays. We determined the crystal structure of YH29143 Fab fragment in complex with TIGIT and identified its epitope that overlaps with the PVR-binding interface. We also studied in vivo efficacy of YH29143 whether to inhibit the growth of tumor in two syngeneic colon tumor-bearing mouse models (CT26 and MC38). YH29143 reduced growth of both tumors compared to that of control IgG. In addition to these results, YH29143 showed synergistic efficacy for inhibition of tumor growth in combination with anti-PD-L1 antibody. From these tumor tissues, the ratio of CD8+ T cells to Treg cells was increased by treatment of anti-TIGIT antibody.

Taken together, we evaluated the efficacy of YH29143, a potent anti-TIGIT monoclonal antibody, which enhanced T cell activation and suppressd Treg cell function in vitro, and efficiently inhibited tumor growth in vivo having synergistic effect with anti-PD-L1 antibody. These data also provide the rationale for YH29143 as a potential combination candidate for cancer immunotherapy with other immune checkpoint blockades.

Citation Format: Kwang-Hoon Lee. A novel anti-TIGIT antibody (YH29143) enhances T cell activity and suppresses Treg cell activity and synergizes with anti-PD-L1 antibody [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4844.
Abstract 4861: Chemotherapy improves overall survival in patients with T2N0M0 non-small cell lung cancer undergoing definitive radiation therapy: An analysis of the SEER database
Authors: Komiya Takefumi , Chaaya Gerard , Powell Emily
Published: August 2019

Objectives: Despite relatively routine practice and recommendations by clinical guidelines, an advantage of adding systemic chemotherapy to definitive radiation in patients with early stage non-small cell lung cancer (NSCLC) has never been demonstrated by randomized or large-scale studies. This study evaluates the role of chemotherapy in addition to thoracic radiation in T2N0M0 NSCLC patients who did not undergo surgical resection.

Materials and Methods: Using the Surveillance, Epidemiology, and End Results (SEER) database, we screened for patients with T2N0M0 NSCLC who received radiation therapy without surgical resection from 2004 to 2015. T-staging was defined according to the American Joint Committee on Cancer (AJCC) 6th (Year 2004+) and 7th(Year 2010+) versions. Kaplan-Meier curves and estimated overall survival according to chemotherapy status were determined by Log-rank test. Both univariate and multivariate analyses were conducted for the AJCC 6th (T2), 7th T2a, and 7th T2b groups. All the statistical analyses were performed using JMP software version 13 (SAS Institute, Cary, NC), and significance was achieved when P-value is below 0.05.

Results: A total of 6,075 and 3,138 patients were identified for AJCC 6th (T2; 3cm -7cm) and 7th (T2a; 3 - 5cm, T2b; 5-7 cm) version, respectively. Administration of chemotherapy was associated with younger age, male sex, non-adenocarcinoma, and high pathologic grade. Kaplan-Meier estimates demonstrated that the chemotherapy group had a statistically significant longer five-year overall survival than the non-chemotherapy group in patients with AJCC 6th T2 (19.9% vs 15.8%, p=0.0023) and AJCC 7th T2b (5-7cm, 20.9% vs 13.6%, p=0.0046) but not those with AJCC 7th T2a (3-5cm, 24.3% vs 21.1%, p=0.4369). Multivariate analyses also revealed that the use of chemotherapy was an independent prognostic factor in AJCC 6th T2 and AJCC 7th T2b.

Conclusions: This study strongly suggests that chemotherapy may benefit non-adenocarcinoma patients with primary tumor larger than 5cm (AJCC 8th T3) undergoing chest radiation.

Citation Format: Takefumi Komiya, Gerard Chaaya, Emily Powell. Chemotherapy improves overall survival in patients with T2N0M0 non-small cell lung cancer undergoing definitive radiation therapy: An analysis of the SEER database [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4861.
Abstract 4869: Chromosomal and telomeric biomarkers of normal tissue injury to evaluate risk of secondary malignancy following IMRT for prostate cancer
Authors: Luxton Jared J. , McKenna Miles J. , Taylor Lynn , Swanson Gregory P. , Bailey Susan M.
Published: August 2019

An overall intent of radiotherapy is to precisely target tumor cells, while minimizing exposures to surrounding normal tissue. Despite successes, there is growing concern that an unacceptably large volume of normal tissue is unavoidably exposed. Chromosome aberrations provide a direct measure of ionizing radiation (IR)-induced DNA damage, as well as an indirect measure of future risk since they are associated with virtually all known cancers. Such structural variants (SVs) include translocations (rearrangements between chromosomes) and inversions (rearrangements within chromosomes), the latter being recently identified as part of a distinctive mutational signature associated with radiation therapy-induced second malignancies. Directional Genomic Hybridization (dGH), is a strand-specific cytogenomics-based methodology for cell-by-cell, high-resolution detection of all SVs, particularly inversions, which when combined with compatible subtelomere probes (Telo-dGH), can be used to distinguish inversions from recombination events (sister chromatid exchange) involving chromosomal termini. Telomeres are critical structural elements that serve to protect the physical ends of chromosomes. Dysfunctional telomeres are associated with instability and carcinogenesis, as well as with a variety of other age-related pathologies (e.g., cardiovascular disease). We are validating Telo-dGH as a prospective “personalized” approach of evaluating normal tissue injury, and therefore future risk, associated with radiation therapy - regardless of tumor type or treatment modality. Here, we report results of monitoring prostate cancer patients before and after intensity-modulated radiation therapy (IMRT) to assess radiosensitivity (toxicity), as well as risk of secondary malignancy and other degenerative late effects. Such a strategy has the potential to better inform patient treatment and management decisions based on predicted individual risk.

Citation Format: Jared J. Luxton, Miles J. McKenna, Lynn Taylor, Gregory P. Swanson, Susan M. Bailey. Chromosomal and telomeric biomarkers of normal tissue injury to evaluate risk of secondary malignancy following IMRT for prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4869.
Abstract 4899: The impact of the EGFR-T790M mutation detection by re-biopsy in EGFR mutant NSCLC patients in the retrospective analysis
Authors: Yoshimura Akihiro , Yamada Tadaaki , Okura Naoko , Uchino Junji , Takayama Koichi
Published: August 2019

Background: EGFR-TKIs show a good anticancer effect in to most of patients with advanced non-small cell lung cancer (NSCLC) harboring EGFR activating mutations. However, it ultimately acquires resistance to EGFR-TKIs. We currently attempt to detect EGFR-T790M mutation by re-biopsy after disease progression, because the third generation EGFR-TKI osimertinib was effective against the refractory tumors with EGFR-T790M mutation. However, the re-biopsy from tumors is relatively invasive and some cases are impossible to biopsy. Therefore, it is a beneficial if we predict the EGFR-T790M mutation before re-biopsy. In this study, we analyzed the patients with disease progression after initial EGFR-TKIs to address the issues.

Methods: 78 advanced NSCLC patients with EGFR mutations were enrolled from five institutions in Japan. In all patients, re-biopsy samples were obtained successfully after the resistance to initial EGFR-TKI treatment We analyzed the relationship between the emergence of EGFR-T790M mutation and clinical parameters including clinical outcomes with EGFR-TKI treatment and EGFR activating mutation status.

Results: Of 78 advanced NSCLC patients with EGFR mutations, 39 patients were EGFR-T790M positive and 39 were negative based on the re-biopsy samples. Of 39 EGFR-T790M positive patients, 2 patients achieved complete response (CR), 33 partial response (PR), and 4 stable disease (SD) by initial EGFR-TKI treatment. In contrast, 1 patient experienced a CR, 19 a PR, 18 SD, and 1 progressive disease (PD) in 39 T790M negative patients. The objective response rate was higher in patients with T790M positive mutations than those with T790M negative mutations (89.7% versus 51.2%, p< 0.01). There was no statistically significant difference in progression free survival and time to failure treated with initial EGFR-TKIs between both groups.

Conclusion: The response to initial EGFR-TKIs treatment might be one of good predictors for emerging of refractory tumors with EGFR-T790M mutation.

Citation Format: Akihiro Yoshimura, Tadaaki Yamada, Naoko Okura, Junji Uchino, Koichi Takayama. The impact of the EGFR-T790M mutation detection by re-biopsy in EGFR mutant NSCLC patients in the retrospective analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4899.