bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract B013: PP2A regulated macropinocytosis and therapeutic vulnerabilities in pancreatic cancer
Authors: Baral Garima , Pfeffer Claire M. , Allen-Petersen Brittany L. , Doraivel Indiraa 
Published: November 2022

Abstract
Pancreatic Ductal Adenocarcinoma (PDAC) is the fourth leading cause of cancer related deaths in the US, with the lowest five-year survival rate of all cancers. Nutrients in the PDAC microenvironment are commonly depleted, with the vital amino acid glutamine among the most deficient metabolites. In an attempt to circumvent this deprivation, PDAC cells initiate KRAS dependent macropinocytosis, an actin-driven nutrient scavenging pathway. Macropinocytosis allows cells to replenish the nutrients required for proliferation and survival. As glutamine is essential for PDAC cell survival, therapeutic inhibition of macropinocytosis represents a novel strategy to suppress nutrient acquisition and drive cell death in PDAC. Protein phosphatase 2A (PP2A) is a heterotrimeric Serine/Threonine phosphatase known to inhibit downstream targets of the KRAS signaling cascade and is implicated in macropinocytosis regulation. We demonstrate that pharmacological activation of PDAC cell lines with the small molecule activator of PP2A, DT061, leads to significant accumulation of intracellular vesicles. Therefore, we hypothesize that PP2A activation results in methuosis, a non-apoptotic cell death process driven by aberrant macropinocytosis. Using high molecular weight TMR-Dextran, we confirmed that these vesicles are macropinosomes. PP2A activation prevented the colocalization of macropinosomes with lysosomes, likely limiting the nutrients supply to PDAC cells. RNA sequencing analysis showed that glutamine deprivation genes are significantly enriched with acute activation of PP2A, and the oxidative phosphorylation pathway was observed to be significantly inhibited. Further, combination of DT061 with Glutamine transport inhibitor V-9302 significantly inhibits the survival of PDAC cells. Together, these findings indicate that activation of PP2A in late stage PDAC promotes aberrant macropinocytosis and establishes a novel role of PP2A in nutrient scavenging and cell death. These pathways can be further exploited to identify potential therapeutics in PDAC.
Citation Format: Garima Baral, Claire M. Pfeffer, Brittany L. Allen-Petersen, Indiraa Doraivel. PP2A regulated macropinocytosis and therapeutic vulnerabilities in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr B013.
Abstract B023: RHAMMB promotes pancreatic cancer metastasis
Authors: Chen Xiang , Zhang Tiantian , Lee Seung Koo , Wang Dunrui , Chen Zhengming , Tung Ching-Hsuan , Chen Yao-Tseng , Du Yi-Chieh Nancy 
Published: November 2022

Abstract
Pancreatic cancer is a leading cause of cancer-related death. The most common type of pancreatic cancer is pancreatic ductal adenocarcinoma (PDAC), and pancreatic neuroendocrine tumor (PNET) is the second common malignancy of pancreas. Pancreatic cancer patients are often diagnosed with metastatic diseases. The 5-year survival is lowest for pancreatic cancer among all cancers. There is an urgent need to understand the key regulators for pancreatic cancer metastasis and develop new therapeutic strategies. We found that Receptor for hyaluronan-mediated motility (RHAMM) is overexpressed in pancreatic cancer, but it is absent or limited in normal human tissues and not expressed in adult pancreas. RHAMM was initially identified as a protein that binds to hyaluronic acid (HA). RHAMM promotes HA-induced motility, modulates cytoskeletal organization, and activates extracellular-regulated kinase (Erk). RHAMM encodes 18 exons and alternative splicing yields different isoforms, RHAMMv1-4. We found that RHAMMB (known as RHAMMv3) is the most prominent alternative splicing isoform in PDAC and PNET, and high RHAMMB mRNA levels correlate with inferior survival of pancreatic cancer patients in TCGA cohort. We demonstrated that RHAMMB overexpression promotes metastasis of pancreatic cancer in mouse models and knockdown of RHAMM by shRNA suppresses migration and metastasis. Given RHAMM’s tumor-specific overexpression patten, we developed nanoparticles to target RHAMMB-overexpressing pancreatic cancer. We demonstrated that RHAMM-targeting nanoparticles loaded with multiple therapeutics can be used as a systemic therapy to suppress RHAMMB-overexpressing tumors in immunocompetent mice. Taken together, RHAMMB plays an important role for pancreatic cancer metastasis and serves as a therapeutic gateway for pancreatic cancer treatment.
Citation Format: Xiang Chen, Tiantian Zhang, Seung Koo Lee, Dunrui Wang, Zhengming Chen, Ching-Hsuan Tung, Yao-Tseng Chen, Yi-Chieh Nancy Du. RHAMMB promotes pancreatic cancer metastasis [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr B023.
Abstract B024: Phosphoinositide focused CRISPR screen reveals ITGAV as a critical gene in pancreatic cancer growth and invasion
Authors: Lee Daniel K.C. , Loke Ryan , To Lydia , Chen Keyue , Chow Jonathan T.S. , Salmena Leonardo 
Published: November 2022

Abstract
Background: Pancreatic Cancer (PC) is one of the most aggressive cancer types, with less than 10% of patients surviving at 5-years. One hallmark of PC is the frequent mutation of the oncogene KRAS resulting in the constitutive activation of the phosphoinositide-3-kinase (PI3K) signaling pathway. The PI3K pathway is an intracellular signaling pathway that regulates cell growth, metabolism, and survival in response to extracellular signals. Given the importance of deregulated phosphoinositide (PI) signaling in PC, we hypothesize that genes coding for PI-metabolizing enzymes and effectors may have significant and unappreciated roles in PC. Methods: We generated a CRISPR knockout (KO) library that targets 1,534 PI-associated genes to discover novel essential genes in PC. Results: In a PANC-1 screen, we identified 106 essential genes across all timepoints, including 28 novel candidate genes and 78 previously identified essential genes. Among six validated candidate genes, we demonstrate that Integrin Subunit Alpha V (ITGAV) is a protein with clinical importance in PC. Treatment of PC cell lines with an ITGAV integrin antagonist as well as KO of ITGAV resulted in reduced cancer associated phenotypes in vitro, including reduced proliferation rate and compromised migration and invasion capacity. Ongoing studies will investigate perturbations in signaling pathways associated with ITGAV, and aim to elucidate roles for ITGAV in metastatic progression and therapy response. Conclusions: Overall, these findings indicate that ITGAV inhibition represents a putative strategy for the treatment of PC.
Citation Format: Daniel K.C. Lee, Ryan Loke, Lydia To, Keyue Chen, Jonathan T.S. Chow, Leonardo Salmena. Phosphoinositide focused CRISPR screen reveals ITGAV as a critical gene in pancreatic cancer growth and invasion [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr B024.
Abstract B036: The role of whole genome duplication in progression of pancreatic ductal adenocarcinoma
Authors: Hummel Lauren , Xie Irene , Ng Karen , Zhang Amy , Ramotar Stephanie , Dodd Anna , O'Kane Grainne , Knox Jennifer , Wilson Julie , Gallinger Steven , Notta Faiyaz 
Published: November 2022

Abstract
Introduction: Pancreatic ductal adenocarcinoma (PDA) is a lethal disease that tends to present at an advanced stage, but the evolutionary mechanisms responsible for rapid progression in PDA are poorly understood. Whole genome duplication (WGD) is a hallmark of cancer observed more frequently in late-stage tumors that predicts poorer overall patient survival across cancer types, including PDA. The genome-wide instability that occurs during WGD events can lead to gene dosage imbalances that promote tumor progression and may explain the rapid progression of aneuploidy. Although WGD has been studied extensively in advanced cancer, there is limited data on WGD in primary tumors. We hypothesize that WGD occurs frequently in primary PDA and promotes the rapid progression and high rate of relapse in early stage PDA. We leveraged scWGS to infer copy number profiles and WGD events from tumor cells to determine the rate of subclonal WGD in primary PDA tumors and understand how aneuploidy and genome instability evolve in the earliest stages of tumor progression. Methods: Single cell barcoded libraries from primary treatment naive tumors were prepared with the 10X Genomics Single Cell CNV platform and sequenced to a depth of 20-60x per tumor. Reads were processed using CellRanger DNA pipeline, demultiplexed, and analyzed with Gingko CNV. A total of 10,323 cells from 8 primary PDA tumors (range, 192 – 3146; median = 1286) were recovered, resulting in an average coverage of 0.06x per single cell (range, 0.02x – 0.14x). Results: 5/8 tumors analyzed had evidence of at least one WGD event. The WGD event was identified as a minor subclone in 3 of these 5. Copy number profiles revealed 1-6 distinct subclones in each tumor, demonstrating copy number evolution is ongoing. WGD+ tumors trend towards having higher diversity and higher percentage of genome altered. Conclusion: WGD occurs more frequently in primary PDA than previously understood, and may confer high levels of genetic instability.
Citation Format: Lauren Hummel, Irene Xie, Karen Ng, Amy Zhang, Stephanie Ramotar, Anna Dodd, Grainne O'Kane, Jennifer Knox, Julie Wilson, Steven Gallinger, Faiyaz Notta. The role of whole genome duplication in progression of pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr B036.
Abstract B039: Development of a selective therapeutic intervention for p53 mutant for pancreatic adenocarcinoma
Authors: Alruwaili Mohammed M. , Zonneville Justin , Alqarni Mohammed A. , Rajan Priyanka , Serio Hannah , Straubinger Robert , Fountzilas Christos , Bakin Andrei 
Published: November 2022

Abstract
Genetic alterations in the tumor suppressor p53 gene (TP53) are found in over 70% of Pancreatic Adenocarcinoma (PAAD) and contribute to poor prognosis, cancer progression and metastasis. Existing treatment options for p53 mutant (p53mut) cancer are limited and there is an urgent need for better therapeutic interventions that can be greatly beneficial to a large proportion of patients with PAAD. Here we present a novel therapeutic strategy for selective targeting p53mut pancreatic tumors. Genomic data revealed that p53-deficient PAADs express high levels of DNA replication genes as well as genes involved in Base Excision (BER) and Mismatch (MMR) Repair, indicating activation of these mechanisms. Evaluation of BER activity by a novel methodology with a modified deoxyuridine analogue showed a significant dysregulation in BER mediated repair in p53mut cancer cells leading to accumulation of p53mut tumor cells in late S/G2 phase. By exploiting this defect, we found that treatment with a deoxyuridine analogue such as trifluorothymidine (TFT, a component of TAS102) resulted in accumulation of DNA breaks selectively in p53mut cells. A deoxyuridine analogue (TFT) did not block DNA replication but rather activated DNA repair leading to DNA breaks in p53mut cells whereas p53 wild type cells accumulated in G1 with minimal DNA damage. Further, we found that inhibition of poly (ADP) ribose polymerase (PARP) enhanced DNA damage and increased cell death selectively in p53mut tumor cells although PARP inhibitor alone was not effective. In contrast, the TAS102-PARPi did not induce DNA damage in the normal cells such as hTERT-immortalized Human Pancreatic Nestin Expressing cells (HPNE). A new TAS102-PARPi combination regimen demonstrated greater inhibition of tumor growth and improved the survival rates in p53mut PAAD xenograft models including Cell-Derived Xenograft (CDX) and Patient-Derived xenograft (PDX) models, compared to either drug alone without adverse effects in mice. Thus, this preclinical work identified a novel and immediately feasible strategy for p53mut disease that may improve treatment and the quality of life for a significant proportion of patients with PAAD while limiting toxic effects on normal tissues.
Citation Format: Mohammed M. Alruwaili, Justin Zonneville, Mohammed A. Alqarni, Priyanka Rajan, Hannah Serio, Robert Straubinger, Christos Fountzilas, Andrei Bakin. Development of a selective therapeutic intervention for p53 mutant for pancreatic adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr B039.
Abstract B041: DCLK1 isoforms 2 and 4 c-terminal extracellular binding domain mediates PDAC tumorigenesis through protein-protein interactions
Authors: Chandrakesan Parthasarathy , Moore Landon , May Randal , Pitts Kamille , Bannerman-Menson Edwin , Brown Milton , Houchen Courtney 
Published: November 2022

Abstract
Doublecortin-like kinase 1 (DCLK1) plays a major role in tumor initiation, progression, and metastasis of solid tumors including pancreatic ductal adenocarcinoma (PDAC). Elevated expression of DCLK1 in patient tumors leads to poor overall survival, however, the precise mechanisms that regulate the pro-tumorigenic functions of DCLK1 continue to be explored. We have reported that the proprietary monoclonal antibody, CBT-15, binds to the C-terminal extracellular domain of DCLK1 isoforms 2/4 in PDAC and treatment with CBT-15 resulted in tumor xenograft growth arrest in PDAC and reduced tumor growth in the KPC mouse model of PDAC. To determine the functional activity of the DCLK1 isoform 2/4 extracellular domain and CBT-15 action, we screened a peptide library against DCLK1 isoform 4 and identified eight peptides that bound to the C-terminal extracellular domain. In this study, we evaluated the biological impact of these peptides on colony and spheroid formation using AsPC-1 and Capan-1 pancreatic cancer cell lines. We found a greater than 90% reduction in spheroid formation compared to vehicle control for Capan-1 cells treated with peptide #1 (1 μM). Furthermore, peptide #1 treatment of AsPC-1 cells derived mouse xenografts resulted in a greater than 65% reduction in xenograft growth (P-value &lt; 0.01, 10 mg/kg, i.p.). This highly active peptide binds the extracellular domain with 60% inhibition at 50 nM determined by SPR and has a Kd of 30±10 nM. To identify potential DCLK1 extracellular domain binding partners, we developed an algorithm that identified five proteins that are key regulators of tumorigenesis and exhibit structural characteristics that would allow for binding to the DCLK1 extracellular domain. Further work is focused on confirming the interactions between DCLK1 extracellular domain and candidate targets as well as whether peptide #1 blockade of protein-protein interactions disrupts pro-tumorigenic functions of DCLK1.
Citation Format: Parthasarathy Chandrakesan, Landon Moore, Randal May, Kamille Pitts, Edwin Bannerman-Menson, Milton Brown, Courtney Houchen. DCLK1 isoforms 2 and 4 c-terminal extracellular binding domain mediates PDAC tumorigenesis through protein-protein interactions [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr B041.
Abstract B044: Bromodomain and Extra-Terminal Protein inhibition decreases pancreatic cancer proliferation via MYC-independent pathways
Authors: Rana Manjul , Kansal Rita G. , Fang Jie , Allen Benjamin T. , Yang Jun , Glazer Evan S. 
Published: November 2022

Abstract
Introduction: The bromodomain and extra-terminal (BET) protein family contains proteins which have evolutionarily conserved bromodomains (BRDs) that specifically recognize acetylated lysine residues on the histone tails of chromatin and regulate gene transcription. Deregulation of these BRD-containing proteins has been seen in carcinogenesis as they are also known to play role in the regulation of the cell-cycle and MYC oncogenes. BMS-986158 is an oral BET inhibitor which has been used in the clinical trials for both hematologic and advanced solid tumor cancers. We hypothesized that BET inhibition (BETi) decreases pancreatic ductal adenocarcinoma (PDA) proliferation. Methods: Pancreatic cancer cell lines and patient-derived cell-lines (PDCLs) were treated with 2.5 to 100nM BMS-986158 for 72 hours to study dose-response effect with Incucyte. We performed RNA-seq, qPCR, protein analysis, and flow cytometry to evaluate comprehensive changes and underlying mechanisms/pathways including epithelial to mesenchymal transition (EMT) and the cancer stem cell (CSC) phenotype. Various doses of BMS-986158 were used in PDCL and PDA patient-derived organoids (PDO) in combination with chemotherapy drug to evaluate combinational effects. Results: We found that BETi induced dose-dependent decrease in growth of PDA and PDCLs and induced cancer cell death. BETi demonstrated PDO growth inhibition which was enhanced when combined with gemcitabine and paclitaxel chemotherapy. Next, we found that BETi did not affect MYC expression but decreased expression of the SNAI1 (a mesenchymal marker) protein and increased E-cadherin protein expression in PDA cell line and PDO consistent with decreased activation of an EMT program. BETi also decreased expression of CD133, a marker of CSCs in PDO. BETi also induced G1/S Phase cell cycle arrest in PDA PDCLs. Furthermore, RNA-seq studies revealed that BETi treatment inhibits KRAS pathway and upregulates pathways involved in metabolism of lipids and lysosomal degradation. RNA-seq and qPCR demonstrated that GPX3 (glutathione peroxidase 3, a key protein in reactive oxygen species response) gene expression is upregulated in BETi treated samples. Conclusions: Thus, our data demonstrate that BETi through BMS-986158 is an additional therapy for inhibiting PDA growth through mechanisms that are independent of MYC pathway, inhibition of abnormal lipid metabolism and scavenging of reactive oxygen species.
Citation Format: Manjul Rana, Rita G. Kansal, Jie Fang, Benjamin T. Allen, Jun Yang, Evan S. Glazer. Bromodomain and Extra-Terminal Protein inhibition decreases pancreatic cancer proliferation via MYC-independent pathways [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr B044.
Abstract B056: Wild-type RAS/MAPK signaling complexes mediate adaptive resistance to KRAS inhibition in PDAC
Authors: Ge Xiangyu , Ruiz Christian F. , Li Wenxue , Quiñones-Avilés Yanixa , Muzumdar Mandar Deepak 
Published: November 2022

Abstract
Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy and predicted to be the second most common cause of death in the US within the next decade. A striking hallmark of PDAC is the presence of activating KRAS mutations in &gt;90% of all cases. Studies in animal models and cell lines have suggested that oncogenic KRAS is important for both the initiation and progression of PDAC, making KRAS an attractive target for therapy. Recent FDA approvals of KRAS mutant-specific inhibitors has advanced the clinical treatment of patients with cancers harboring mutant KRAS, yet resistance inevitably occurs through both genetic (second-site mutations, bypass pathways) and non-genetic (adaptive) mechanisms. Elucidating the adaptive mechanisms by which cancers evade KRAS inhibition in PDAC will enable the development of more efficacious and durable combinatorial therapeutic strategies with emerging KRAS inhibitors. To address this gap in knowledge, we used CRISPR/Cas-mediated gene knockout technology to model KRAS inhibition in PDAC and found that KRAS is dispensable in a subset of human and mouse PDAC cells, arguing that KRAS is not absolutely required for tumor maintenance. KRAS-deficient cells showed enhanced sensitivity to phosphoinositide 3-kinase (PI3K) inhibitors (PI3Ki), which functioned not only to block canonical AKT signaling but also, unexpectedly, to suppress mitogen-activated protein kinase (MAPK) signaling through rapid attenuation of wild-type RAS/MAPK activity in single cells. Importantly, we confirmed this novel regulatory role of PI3K in mediating RAS/MAPK activity across multiple wild-type KRAS-expressing malignant and non-malignant cell lines, supporting the generalizability of this signaling axis. Furthermore, unbiased proximity protein labeling (BioID) revealed that PI3K inhibition reduces the interaction of KRAS with canonical regulators, effectors, and scaffolds in RAS/MAPK signaling. Parallel genome-wide CRISPR screens comparing KRAS intact and isogenic KRAS-deficient PDAC cells revealed specific RAS/MAPK scaffold/docking proteins as essential for PDAC cell fitness following KRAS ablation. Together, our work sheds new light into the regulatory role of PI3K in wild-type RAS/MAPK signaling, highlights the importance of functional wild-type RAS/MAPK signaling complexes in adaptive resistance to KRAS inhibition, and nominates potential therapeutic targets to overcome resistance to KRAS inhibition in PDAC and possibly other KRAS mutant cancers.
Citation Format: Xiangyu Ge, Christian F. Ruiz, Wenxue Li, Yanixa Quiñones-Avilés, Mandar Deepak Muzumdar. Wild-type RAS/MAPK signaling complexes mediate adaptive resistance to KRAS inhibition in PDAC [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr B056.
Abstract B062: Activation of the MAPK pathway by altered RNA splicing in cancer
Authors: Zhang Yushan , Siraj Md Afjalus , Chakrabarty Prabir , Tseng Robert , Das Shamik , Bhattacharya Resham , Escobar-Hoyos Luisa , Mukherjee Priyabrata 
Published: November 2022

Abstract
Many cancers carry recurrent, change-of-function mutations affecting RNA splicing factors, however, less is known about the consequences of upregulated RNA splicing factors (SFs) in cancer. Here, we describe a role of survival motor neuron domain containing 1 (SMNDC1) protein, a poorly studied SF that we found to be upregulated in pancreatic ductal adenocarcinoma (PDAC) and high-grade serous ovarian cancers (HGSOCs) and associated with poor patient prognosis. By loss- and gain-of- function approaches we found that SMNDC1 promotes cancer cell proliferation, clonal expansion and tumor growth. Mechanistically, SMNDC1 promoted the retention of A/C-rich exons which otherwise would be excluded or less retained after RNA splicing in normal cells. Inclusion of exon 4 (E4) of MAPK3 (ERK1), which encodes both phosphorylation sites (Thr202/Tyr204) of the kinase, was among the promoted exons by SMNDC1. Forced exclusion of MAPK3 E4 using anti-sense oligos in vitro and in vivo, inhibited the phosphorylation of ERK1/2, the expression of downstream genes (Cyclin D1, Elk1) and increased proapoptotic proteins. These data provide a novel mechanism by which PDAC and HGSOC cells exploit a “splicing switch” that increases ERK1 phosphorylation, and offer a druggable alternative to target these cancer cells by jointly blocking oncogenic signaling and altered RNA splicing.
Citation Format: Yushan Zhang, Md Afjalus Siraj, Prabir Chakrabarty, Robert Tseng, Shamik Das, Resham Bhattacharya, Luisa Escobar-Hoyos, Priyabrata Mukherjee. Activation of the MAPK pathway by altered RNA splicing in cancer [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr B062.