bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 1964: The mutational pattern of cell cycle checkpoints and regulators in Egyptian colorectal cancer patients
Authors: El-Din Youssef Amira Salah , Lotfy Mai M. , Nassar Auhood , Zekri Abdel-Rahman N. 
Published: July 2021

Abstract
Background: Uncontrolled proliferation is a hallmark of cancer cells. Many cell cycle checkpoints and regulators are altered in tumors which in turn results in the accumulation of genetic aberrations. So, this study aimed to identify the mutational profile of cell cycle checkpoints and regulators in tissue biopsies in Egyptian Colorectal Cancer patients.
Material and Methods: Sixty two fresh tissues samples were collected from Egyptian patients with CRC. The libraries were performed using Qiaseq UMI-based targeted panel.The detected genetic variants with an average coverage of 500x were annotated using Ingenuity Variant analysis (IVA) and pathway analysis was performed using Ingenuity Pathway analysis (IPA).
Results: Data analysis revealed that TP53& ATM genes; the checkpoints at G1/S and G2/M phases, were highly mutated. They harbored 12 and 9 pathogenic mutations respectively, which cause loss of functionality. The most frequently detected pathogenic variants were c.121delG (58%) in the TP53 & c.640delT (29%) in the ATM. While CHECK2; the checkpoint at G2/M phase, harbored 4 pathogenic variants; c.430delC (16%) was the most detected one. Also, two pathogenic variants were detected in the M phase checkpoint BUB1B and the most frequently detected one was c.1669delA (37%). We also detected pathogenic variants involved in the G1/S phase regulators; SMAD4 (c.1241delT (23%)), CDKN2A (c.238delG (18%)), STK11 (c.340delG (11%)), and CDH1 (c.1955delT (19%)). Other pathogenic variants involved in G2/M phase regulators were also detected; BRCA1 (c.3214delC (16%)) & EP300 (c.4408delA (19%)). Moreover, we detected 2 pathogenic variants in M phase regulator; CDC27 (c.1998delA (7%) & c.2070delA (5%)).
Conclusion: Our data showed the deregulated pattern of cell cycle checkpoints and regulators that are crucial for understanding colorectal cancer progression in Egyptian patients. Also, it may help in developing personalized targeted therapies that efficiently target the cell cycle genes mutations, thereby limits the CRC progression in those patients.
Citation Format: Amira Salah El-Din Youssef, Mai M. Lotfy, Auhood Nassar, Abdel-Rahman N. Zekri. The mutational pattern of cell cycle checkpoints and regulators in Egyptian colorectal cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1964.
Abstract 1965: Discovery of ZN-c3, a potent Wee-1 inhibitor with a differentiated pharmacologic and kinase selectivity profile
Authors: Li Jiali , Boren Brant , Huang Peter Q. , Bunker Kevin D. , Doñate Fernando , Samatar Ahmed A. 
Published: July 2021

Abstract
Genome instability initiated by DNA damage or DNA replication stress is a driver of tumor development. To ensure the accuracy of DNA replication, DNA damage response (DDR) mediated by various cell cycle checkpoints activate the DNA repair system. One such checkpoint system is the G2-M checkpoint which is involved in the repair and prevention of excessive DNA damage. A key regulator of the G2-M checkpoint is the Wee1 kinase which causes cell cycle arrest to prevent damaged cells from entering mitosis. Thus, inhibition of Wee1 should prevent G2-M checkpoint activation which would lead to unscheduled mitotic entry and induction of apoptosis. Small-molecule inhibitors of Wee1 are currently being tested in several tumor types. Preliminary results show promising clinical activity of AZD-1775, a potent inhibitor of Wee1, however, achieving an optimal dose and a schedule that is well-tolerated has been a challenge. Here, we describe the characterization of ZN-c3, a potent, selective and orally bioavailable small-molecule inhibitor of Wee1. ZN-c3 exhibits potent anti-proliferative activity across multiple tumor cell lines. Compared to AZD-1775, ZN-c3 has superior selectivity profile against a panel of kinases. In vivo, ZN-c3 induced tumor regression as a single agent in several tumor models including non-small cell lung cancer, ovarian cancer, and uterine sarcoma. In combination studies, ZN-c3 potentiates the antitumor efficacies of carboplatin and gemcitabine. The pharmacokinetic and efficacy profiles of ZN-c3 and AZD-1775 were compared in tumor xenograft models. ZN-c3 showed higher plasma and tumor exposure than AZD-1775, which correlated with more potent tumor growth inhibition than AZD-1775. In summary, ZN-c3, with its key differentiated pharmacologic and kinase selectivity profile, is a promising new generation of DDR inhibitor. ZN-c3 is currently in clinical development for the treatment of advanced solid cancers.
Citation Format: Jiali Li, Brant Boren, Peter Q. Huang, Kevin D. Bunker, Fernando Doñate, Ahmed A. Samatar. Discovery of ZN-c3, a potent Wee-1 inhibitor with a differentiated pharmacologic and kinase selectivity profile [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1965.
Abstract 1980: Non-canonical regulation and function of anti-apoptotic protein c-FLIP
Authors: Tsegaye Matyas Abel , McGeehan Kyle , Nemera Mati , Schafer Zachary T. 
Published: July 2021

Abstract
The metastasis of cancer cells to distant sites accounts for over 90% of cancer related deaths. In order to metastasize, cancer cells must be able to survive during extracellular matrix (ECM) detachment, namely by blocking anoikis (a caspase-dependent cell death) and restoring metabolic deficiencies. Such barriers during tumorigenesis are abrogated through activation of oncogenic signaling, and/or inhibition of tumor suppressors. Elucidating the signaling pathways involved in cancer cell metastasis is a crucial step in designing effective therapeutic interventions. Surprisingly, our investigation has revealed that cellular FLICE-like Inhibitory Protein (c-FLIP), a protein well known for its pro-survival function, instead antagonizes the viability of ECM-detached cancer cells. Additionally, we demonstrated that signaling emanating from oncogenic growth factor receptors results in the downregulation of c-FLIP expression providing additional evidence that cancer cells may benefit from diminished FLIP levels. Interestingly, this repression of c-FLIP expression by activated oncogenes is a consequence of PI3K signaling. Our study also suggests that low c-FLIP levels are beneficial in cancer cells due to capacity of c-FLIP to induce β-catenin degradation. Taken together, our study has revealed an unexpected role for c-FLIP in restricting the viability of tumor cells and raises the idea that the c-FLIP may have context-dependent pro- and anti-cell death roles during tumorigenesis.
Citation Format: Matyas Abel Tsegaye, Kyle McGeehan, Mati Nemera, Zachary T. Schafer. Non-canonical regulation and function of anti-apoptotic protein c-FLIP [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1980.
Abstract 1981: TGF-β induced PLEK2 promotes metastasis and chemoresistance in ESCC by up-regulation of LCN2
Authors: Wang Feng , Zhang Chaoqi , Liu Chengming , Cheng Hong , Sun Nan , He Jie 
Published: July 2021

Abstract
Background: Esophageal squamous cell carcinoma (ESCC) patients suffer from poor prognosis in general. Novel molecular markers to predict prognosis and serve as potential therapy target are much needed. Our previous research has established a comprehensive database of ESCC (GSE53625). Combined with data from TCGA, we found Pleckstrin 2 (PLEK2) predicts poor prognosis in ESCC. Meanwhile, its role in ESCC progression remains unknown.
Methods: The TCGA database and GSE53625 are used to establish the expression profiles of PLEK2 and overall survival rates. Loss-of-function assays were performed to examine the effect of PLEK2 on proliferation, migration and invasion of ESCC cells in vitro and in vivo. ChIP assay was used to detect the relationship between TGF-β and PLEK2. Western blot and quantitative real time PCR (qRT-PCR) were carried out to reveal the interrelation between PLEK2 and LCN2.
Results: PLEK2 had a higher expression in ESCCs and predicted poor overall survival (OS). PLEK2 attenuation by shRNA was sufficient to decrease ESCC cells proliferation, clonogenicity, migration and invasion in vitro and tumorigenicity and distant metastasis in vivo. Conversely, elevating PLEK2 levels performed opposite effects. Downregulation of PLEK2 led to higher proportions of apoptotic ESCC cells when induced by Cisplatin. The high expression of PLEK2 in ESCC patients also linked to shorter OS of patients who received adjuvant chemotherapy. TGF-β could increase the expression of PLEK2 by stimulation of Smad2/3 which can bind directly with the promoter sequences of PLEK2. Analyses of transcriptome profiling suggested LCN2 as the downstream of PLEK2. Overexpression LCN2 in PLEK2 stable knockdown ESCC cells can reverse the decreased migration and invasion, but not the proliferation of ESCC cells. TGF-β increased the expression of LCN2, but the effect disappeared when PLEK2 was knockdown. We also find that AKT pathway is involved in the whole regulatory processes.
Conclusion: Our results revealed the significance of PLEK2 in driving oncogenesis and metastasis in ESCC by regulating LCN2 which activates AKT pathway. We also indicated that PLEK2 was associated with chemo-resistance. Our findings indicates the potential use of PLEK2 as a prognostic biomarker and a candidate therapeutic target in ESCC.
Keywords: PLEK2; ESCC; TGF-β; chemo-resistance
Citation Format: Feng Wang, Chaoqi Zhang, Chengming Liu, Hong Cheng, Nan Sun, Jie He. TGF-β induced PLEK2 promotes metastasis and chemoresistance in ESCC by up-regulation of LCN2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1981.
Abstract 1986: p53/FBXL20 axis negatively regulates the protein stability of PR55α, a PP2A regulatory subunit
Authors: Yan Ying , Madduri Lepakshe , Brandquist Nichole , Palanivel Chitra , Zhou Sumin , Enke Charles , Ouellette Michel 
Published: July 2021

Abstract
PP2A holoenzymes are the majority of Ser/Thr phosphatases in human cells and each PP2A complex contains one scaffold subunit, one catalytic subunit, and one regulatory subunit. PP2A regulatory subunits, existing in four sub-families encoded by 15 genes, determine the substrate specificities and intracellular localizations of PP2A. We previously reported an essential role for PR55α, a PP2A regulatory subunit, in the support of malignant potential of pancreatic cancer cells, which includes promoting YAP-activation that supports anchorage-independent growth and metastasis. Furthermore, our data showed that PR55α level is elevated in pancreatic cancer relative to normal tissues and high PR55α levels correlate with poor patient survival. The studies in this report reveal a novel mechanism by which the p53 tumor suppressor negatively regulates PR55α protein stability. The results show that p53 inactivation by siRNA-knockdown, gene-deletion, HPV-E6 promoted degradation, or p53R175H mutant expression all results in the increase of PR55α expression. Subsequent studies demonstrate that this p53 function is mediated through its target gene FBXL20, a substrate recognition component of the SCF (Skp_Cullin_F-box) ubiquitin ligase complex that facilitates proteasomal degradation. As a result, the expression of mutant p53R175H in human pancreatic ductal cells mimics the PR55α effect, increasing c-Myc protein stability, and promoting anchorage-independent proliferation. Additionally, FBXL20 mRNA levels are significantly reduced in pancreatic cancers relative to normal control, and low FBXL20 levels correlate with poor patient survival, both of which inversely resemble the pathological effects of PR55α in pancreatic cancer. Collectively, these results define a novel p53 function in the suppression of PR55α expression.
Citation Format: Ying Yan, Lepakshe Madduri, Nichole Brandquist, Chitra Palanivel, Sumin Zhou, Charles Enke, Michel Ouellette. p53/FBXL20 axis negatively regulates the protein stability of PR55α, a PP2A regulatory subunit [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1986.
Abstract 1988: Association between CEACAMs and hypoxia defines gastric cancer progression
Authors: Poirah Indrajit , Chakraborty Debashish , Dixit Pragyesh , Samal Supriya , Padhan Pratyush Kumar , Barik Alok , Singh Shivaram Prasad , Singer Bernhard B. , Bhattacharyya Asima 
Published: July 2021

Abstract
Background: Gastric cancer is one of the most prevalent cancers. As in many other solid tumors, hypoxia is a notable feature in gastric cancer as well. The hypoxic microenvironment promotes cancer by modulating expression of several master regulator oncoproteins. Carcinoembryonic antigen-related cell adhesion molecules or (CEACAMs) are adhesion proteins that have been associated with many epithelial tumors but their expression pattern in hypoxic gastric epithelial cells are not known. Since these membrane proteins have widespread roles in the intracellular and intercellular signaling, inflammation, angiogenesis and metastasis, we examined hypoxia-mediated regulation of CEACAM proteins.
Methods: AGS, MKN45 and primary gastric epithelial cells were subjected to hypoxia of varying degrees and the changes in the CEACAM protein profile were evaluated by immunoblotting, FACS assay and immunofluorescence microscopy. In vitro DNA-binding assay and luciferase assays were performed to assess the transcriptional regulation of CEACAMs. Overexpression and suppression studies were also performed to elucidate upstream regulations of CEACAM proteins. Gastric cancer biopsy tissues were examined from consenting patients by performing fluorescence and confocal microscopy.
Results: We found that varying degrees of hypoxia differentially modulate CEACAM expression in gastric cancer epithelial cells which in turn leads to altered proliferation and invasiveness of cancer cells. Interestingly, gastric adenocarcinoma and metastatic gastric cancer biopsies show distinct CEACAM signatures. These findings unfold further avenues highlighting the importance of CEACAM proteins as biomarkers of gastric cancer and as therapeutic targets to treat gastric cancer.
Funding: Department of Atomic Energy (DAE).
Citation Format: Indrajit Poirah, Debashish Chakraborty, Pragyesh Dixit, Supriya Samal, Pratyush Kumar Padhan, Alok Barik, Shivaram Prasad Singh, Bernhard B. Singer, Asima Bhattacharyya. Association between CEACAMs and hypoxia defines gastric cancer progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1988.
Abstract 1993: Off-target effects of ultra-low dose dimethyl sulfoxide on targetable signaling events in lung cancer in vitro models
Authors: Baldelli Elisa , Subramanian Mahalakshmi , Alsubaie Abduljalil M. , Baglivo Sara , Hodge K A. , Bianconi Fortunato , Ludovini Vienna , Crino' Lucio , Petricoin Emanuel F. , Pierobon Mariaelena 
Published: July 2021

Abstract
Background: The identification of targetable alterations in cancer continues to offer novel opportunities to the drug discovery process. However, pre-clinical testing often requires solubilization of these drugs in cosolvents like dimethyl sulfoxide (DMSO). Using commercially available models commonly used for in vitro drug screening and pre-clinical testing, we explored the DMSO off-target effects on functional signaling networks, drug targets, and downstream substrates.
Materials and Methods: Eight commercially available Non-Small Cell Lung Cancer (NSCLC) cell lines were incubated with three ultra-low concentrations of DMSO (0.0008%, 0.002%, and 0.004% v/v, respectively) for 5 min, as well as 1, 6 and 24 hours. Following incubation, expression and activation levels of 183 proteins were captured using Reverse Phase Protein Array (RPPA) technology, of which 134 were kinases and downstream substrates.
Results: The DMSO effect was heterogenous across cell lines and varied based on multiple factors including: concentration, exposure time, and cell line. Of the 183 proteins measured, 88% were statistically significant at the highest DMSO concentration, followed by 81% and 67% at lower concentrations. Only 28 proteins were found statistically different in more than 5 cell lines indicating heterogenous response across models. pERK 1/2 T202/Y204 emerged as the most frequently affected node along with stress-induced response and mitogenic proteins. These cell line specific DMSO-induced alterations, may modulate response to targeted agents and chemotherapeutics.
Conclusions: Ultra-low DMSO concentrations have broad and heterogenous effects on targetable signaling proteins which are model, time, and concentration dependent. As such, off-target effects need to be carefully evaluated in the design and implementation of pre-clinical drug screening and testing.
Citation Format: Elisa Baldelli, Mahalakshmi Subramanian, Abduljalil M. Alsubaie, Sara Baglivo, K A. Hodge, Fortunato Bianconi, Vienna Ludovini, Lucio Crino', Emanuel F. Petricoin, Mariaelena Pierobon. Off-target effects of ultra-low dose dimethyl sulfoxide on targetable signaling events in lung cancer in vitro models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1993.
Abstract 2014: Identification of Smurf2 as a HIF-1α degrading E3 ubiquitin ligase
Authors: Zhao Shuai , El-Deiry Wafik S. 
Published: July 2021

Abstract
The major adaptive response to hypoxia involves HIF-1α which is conventionally regulated by VHL E3 ligase. Our previous experiments suggested a stabilization of HIF-1α by CDK1 and CDK4/6 that is independent of VHL, hypoxia or p53, and that CDK4/6 inhibitors destabilizes HIF-1α under normoxia and hypoxia. To further investigate the molecular mechanism of HIF-1α destabilization by CDK1 or CDK4/6 inhibitors, we performed a proteomic screen on immunoprecipitated HIF-1α from hypoxic colorectal cancer cells that were either untreated or treated with CDK1 inhibitor Ro3306 and CDK4/6 inhibitor palbociclib. Our proteomics screen identified a number of candidates that were enriched in palbociclib-treated hypoxic cells including SMAD specific E3 ubiquitin protein ligase 2 (Smurf2). In addition, we identified a HIF-1α peptide that appeared to be differentially phosphorylated after palbociclib treatment. Gene knockdown of Smurf2 increased basal expression of HIF-1α that was further increased in the presence of Ro3306 or two different CDK4/6 inhibitors, palbociclib and abemaciclib. Overexpression of Smurf2 inhibited expression of HIF-1α and enhanced HIF-1α ubiquitination in normoxia. Proteasome inhibitor MG-132 partially rescued HIF-1α expression when Smurf2 was overexpressed. Overexpression of Smurf2 is correlated with improved disease-free survival and overall survival in clear cell renal cell cancer. Our results unravel a previously unknown mechanism involving Smurf2 for HIF-1α destabilization in CDK4/6 inhibitor-treated cells, thereby shedding light on VHL-independent HIF-1α regulation.
Citation Format: Shuai Zhao, Wafik S. El-Deiry. Identification of Smurf2 as a HIF-1α degrading E3 ubiquitin ligase [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2014.
Abstract 2019: Drug repositioning to induce the synthetic lethality in cancer cells with GSH-depleting therapy
Authors: Otsuki Yuji , Nagano Osamu , Saya Hideyuki 
Published: July 2021

Abstract
The major cellular antioxidant glutathione (GSH) protects cancer cells from oxidative damage that can lead to the induction of ferroptosis. Inhibitor of the GSH synthesis including buthionine sulfoximine (BSO) and cystine-glutamate antiporter subunit xCT, which mediates the uptake of extracellular cystine and thereby promotes GSH synthesis, thus potential anticancer agents. However, the efficacy of xCT or GSH synthesis-targeted therapy has been found to be diminished by metabolic reprogramming that affects redox status in cancer cells. In this study, we performed a synthetic lethal screen of a drug library to identify agents that sensitize the GSH deficiency-resistant cancer cells to the xCT inhibitor sulfasalazine (SSZ). This screen identified the oral anesthetic dyclonine (DYC) which act as a covalent inhibitor for aldehyde dehydrogenases (ALDHs). Treatment with DYC induced intracellular accumulation of the toxic aldehyde 4-hydroxynonenal (4-HNE) in a cooperative manner with SSZ. The combination of DYC and SSZ cooperatively suppressed the growth of SSZ-resistant tumors. Furthermore, we recently found that a vasodilator oxyfedrine (OXY) also possess the similar structure with dyclonine and induce cell death in BSO-resistant cancer cells both in vitro and in vivo. Microarray analysis of tumor xenograft tissue showed cyclooxygenase-2 expression as a potential biomarker for the efficacy of such combination therapy. Moreover, OXY-mediated ALDH inhibition was found to sensitize cancer cells to GSH depletion induced by radiation therapy in vitro. Our findings thus establish a rationale for repurposing of OXY as a sensitizing drug for cancer treatment with agents that induce GSH depletion.
Citation Format: Yuji Otsuki, Osamu Nagano, Hideyuki Saya. Drug repositioning to induce the synthetic lethality in cancer cells with GSH-depleting therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2019.