bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 5708: Silence exportin 7 sensitizes esophageal squamous cell cancer to CDK4/6 inhibition through block the cell cycle coresectory
Authors: Wu Zhong , Xu Lin , Jiang Chuang , Bass Adam , Zhou Jin
Published: March 2024

Introduction: There is a lack of effective target therapies for esophageal squamous cell cancer. Our previous studies have demonstrated that CDK4/6 is a potency target for ESCC and combination with ERBB inhibitors is sufficient to achieve durable response. The aim of the current study is to prospectively map the landscape of sensitivity and resistance to CDK4/6 inhibition and develop novel combination therapies in ESCC.

Experimental Procedures: We performed a genome-wide functional genetic screening and mini-pool designed CRISPR screen approaches to identify the modulators whose depletion sensitize CDK4/6 inhibition or confer resistance to the CDK4/6 inhibitor Palbociclib and elucidate new therapeutic strategies.

Results: Our screen identified RB as the most enriched sgRNA, while guides targeting CCNE1 and CDK2 as the most depletion sgRNAs after CDK4/6 inhibition. These results validates our experimental approach as RB loss and CCNE1/CDK2 reactivation is the main mechanisms of CDK4/6 resistance. After gathering potential candidates from both screens, we found that genetically ablation of Exportin 7, a nuclear export factor, strongly sensitize CDK4/6 inhibition both in vitro and in vivo. RNAseq revealed a further repression of transcriptional activity of E2F and G2M by addition of XPO7depletion under CDK4/6 inhibitor treatment. To increase our insight in the molecular mechanism that could explain the synergy between XPO7 and CDK4/6, we further performed proteomics of nuclear and cytoplasm in ESCC lines with or without CDK4/6 inhibition. We found that silence XPO7 result in nuclear accumulation of mitosis-regulated genes such as CENPM, KIF4A and WEE1. Combined CDK4/6 inhibition with XPO7 depletion results in further downregulate of CENPM and KIF4A expression in nucleus, abrogating compensatory activation of cell cycle regulation and promote the cytostatic effect in ESCC. We further validated that CENPM and KIF4A depletion also sensitize CDK4/6 inhibition, and consequentially use WEE1 inhibitor after CDK4/6 inhibitor also effectively block the growth of ESCC lines.

Conclusion: Overall, our comprehensive functional genetic screening approach revealed modulation of sensitive and resistance to the inhibition of CDK4/6 in ESCC. XPO7 was identified as a driver to change cell cycle landscape and merits as a therapeutic target combined with CDK4/6 inhibition in ESCC, which is beneficial to provide a novel treatment strategy.

Citation Format: Zhong Wu, Lin Xu, Chuang Jiang, Adam Bass, Jin Zhou. Silence exportin 7 sensitizes esophageal squamous cell cancer to CDK4/6 inhibition through block the cell cycle coresectory [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5708.
Abstract 5716: CDK7 as a drug target in advanced stage uveal melanoma
Authors: Waltrich Francis J.
Published: March 2024

Uveal melanoma (UM) metastasizes predominantly to the liver, and most metastatic UM are BAP1-deficient. Targeted therapies, such as MEK inhibitors, have failed clinically. There are few FDA-approved therapies for metastatic UM, but these therapies are limited to only a subset of patients and have modest survival benefits. Hence, there is a need to identify novel and effective treatment strategies. Due to the low mutational burden in UM, targeting transcriptional may be an effective strategy. Here, we identified Cyclin Dependent Kinase 7 (CDK7), a key regulator of transcription, as an essential and druggable target in UM. CDK7 directly phosphorylates RNA polymerase II and is expressed in all UMs. siRNA-mediated knockdown of CDK7 decreased the growth of three BAP1-deficient UM cell lines. We tested a clinically relevant, highly specific CDK7 inhibitor, SY-5609, developed by Syros Pharmaceuticals and similarly showed that the cell lines were sensitive to the growth inhibitory effects of SY-5609. Furthermore, we observed synergistic effects on cell growth inhibition when combined with a MEK inhibitor (Trametinib). We performed RNA sequencing and identified several Hallmark Genesets to be positively enriched, including interferon-gamma response, TGF-beta signaling, and NFκB signaling after treatment with SY-5609. These results are validated using a multi-omic approach, utilizing Reverse Phase Protein Array (RPPA) data to validate transcriptome to proteome expression of these enriched pathways. Overall, our studies indicate that targeting CDK7 in uveal melanoma is a potential treatment strategy for BAP1-deficient UM and enhances MEK inhibitor efficacy.

Citation Format: Francis J. Waltrich. CDK7 as a drug target in advanced stage uveal melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5716.
Abstract 5724: Preclinical evaluation of a novel CHK1 inhibitor encapsulated within the liposome, SMP-3124, for the treatment of solid cancer
Authors: Kumagai Yuka , Inagaki Ryosaku , Shimizu Kana , Hirose Wataru , Shimada Naoaki , Hayashi Kento , Fukuoka Yoshiko , Matsuoka Makoto , Kamioka Seiji , Ban Hitoshi , Umehara Hiroki , Sawayama Yusuke
Published: March 2024

Checkpoint kinase 1 (CHK1) is a serine/threonine kinase which plays a critical role for DNA damage responses (DDR) throughout the cell cycle in human cells. CHK1 is mainly activated by replication stress resulting in single-stranded DNA breaks induced by chemotherapeutic agents or mutations in DNA repair related genes. These kinds of stresses are reported to increase the dependency on DDR pathway molecule including CHK1. Therefore, targeting CHK1 is promising strategy for drug discovery. In fact, CHK1 inhibition induces S phase arrest and inhibits cell growth in wide range of cancer cell lines. Recently, a number of drugs in this pathway are tested in clinical trials. Although some of them showed obvious clinical responses in both monotherapy and combination therapy, their efficacies are limited because of their toxicities. To maximize the efficacy, we utilized CHK1 inhibitor with liposomal formulation which changes drug distribution to achieve longer drug retention in plasma and accumulation in tumor. Here, we generated SMP-3124, a novel and selective CHK1 inhibitor encapsulated within the liposome. SMP-3124 showed durable pharmacodynamic response due to the liposomal accumulation in the tumor in xenograft model. We confirmed potent anti-tumor activities of SMP-3124 in multiple subcutaneous xenografted models without severe side effects. In addition, SMP-3124 showed prolonged overall survival in both peritoneal dissemination and orthotopic model using human ovarian cancer cells. SMP-3124 synergistically inhibited tumor growth in combination with gemcitabine without additional hematological toxicities induced by gemcitabine. We are planning to an investigational new drug application in 2024.

Citation Format: Yuka Kumagai, Ryosaku Inagaki, Kana Shimizu, Wataru Hirose, Naoaki Shimada, Kento Hayashi, Yoshiko Fukuoka, Makoto Matsuoka, Seiji Kamioka, Hitoshi Ban, Hiroki Umehara, Yusuke Sawayama. Preclinical evaluation of a novel CHK1 inhibitor encapsulated within the liposome, SMP-3124, for the treatment of solid cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5724.
Abstract 5742: Therapeutic efficacy of CA102N in pancreatic cancer
Authors: Lin Louis , Tu Shuling , Tchaparian Eskouhie
Published: March 2024

Pancreatic ductal adenocarcinoma (PDAC) is a challenging cancer to treat due to its aggressive nature and late-stage diagnosis. Considering the lack of effective therapies, there is an urgent need to develop new and effective therapeutics to improve the prognosis of patients. CA102N is a carrier-mediated novel anticancer product where hyaluronic acid is conjugated to Nimesulide-NH2. CA102N is currently under development for the treatment of solid tumors, including colorectal cancer. CA102N was safe and well tolerated in the first-in-human trial in patients with locally advanced or metastatic solid tumors. In the present study, the in vitro anticancer activity of CA102N was investigated in K-ras mutant PANC-1 pancreatic cancer cells. The antitumor efficacy was also tested in vivo in the PANC-1 mice model. Results demonstrated that CA102N inhibits cell growth, cell migration, angiogenesis, and cell proliferation in both K-ras mutant PANC-1 pancreatic cancer cells or tumors. Administration of CA102N in PANC-1 xenografts resulted in a dose-dependent and statistically significant decrease in tumor growth at 9.8 mg/kg and 14.7 mg/kg Nim equivalents, respectively, compared to the vehicle control group. A significant decrease (80%) in liver metastasis was also noted in the PANC-1 orthotopic mice model at 19.6 mg/kg Nim equivalents dose level. Mechanistically, CA102N was found to suppress the PI3k/Akt/mTOR and Raf/MEK/ERK signaling pathways, in addition to reducing the expressions of the N6-methyladenosine (m6A) reader and writer proteins, OCT3/4 transcription factor and RAS levels in vivo. CA102N also modified the tumor stroma and improved drug permeability in vivo. Based on this compelling data, CA102N shows promise as a potential treatment for pancreatic cancer. Combination therapies and regimens are currently being explored in in vivo models as a strategy for clinical development.

Citation Format: Louis Lin, Shuling Tu, Eskouhie Tchaparian. Therapeutic efficacy of CA102N in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5742.
Abstract 576: The pan-quadruplex drug QN-302 selectively down-regulates key pathway targets in pancreatic cancer cells that are up-regulated in human pancreatic cancer
Authors: Neidle Stephen , Ahmed Ahmed A. , Arshad Tariq
Published: March 2024

We have previously disclosed (Ahmed et al, ACS Med Chem Lett, 2020) a novel small molecule G-quadruplex binding compound, QN-302, that is highly potent in pancreatic ductal adenocarcinoma (PDAC) cells and in several in vivo models for this disease. QN-302 was invented at University College London UK and has been subsequently developed by Qualigen Therapeutics Inc. It was cleared by the FDA in August 2023 for Phase 1a clinical trials in USA and is currently under clinical evaluation. RNA-seq whole-genome transcriptome analysis revealed that QN-302 selectively targets G-quadruplexes in cancer-related genes, notably by forming stable G-quadruplex complexes with appropriate promoter sequences. This results in the transcriptional down regulation of affected genes, which map to for example, the hedgehog, axon guidance, WNT/β-catenin and P38 signal transduction pathways. In many instances individual expression changes are modest, though statistically significant: cumulatively, they affect whole pathways. We have revisited the RNA-seq data for QN-302 in PDAC MIA-PACA2 cells (GSE151741 at https://www.ncbi.nlm.nih.gov/geo/) in detail and now identify a small group of eleven down-regulated genes, all with >3-fold expression changes. Interestingly all these genes and their genes products have been previously identified as playing a role in human PDAC (they also have varying roles in other cancer types). Some have been validated as anticancer targets. 10/11 of these genes (https://www.proteinatlas.org/) have been previously reported as being over-expressed in significant fractions of large (>150) groups of human cancer patients from The Cancer Genome Atlas (TCGA) project. Cellular transcriptome data on these eleven genes is presented here, which together with earlier reports on them, supports the designation of QN-302 as a pan-G-quadruplex agent targeting a group of major genes involved in PDAC maintenance and metastasis. Data from a xenograft model for pancreatic cancer is also available for four of these genes, which concurs with the cellular data. We suggest that the identification of these 11 genes may also provide a basis for biomarker selection and possible patient stratification based on transcriptome data.

Citation Format: Stephen Neidle, Ahmed A. Ahmed, Tariq Arshad. The pan-quadruplex drug QN-302 selectively down-regulates key pathway targets in pancreatic cancer cells that are up-regulated in human pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 576.
Abstract 5786: Epstein-Barr virus nuclear antigen 1 (EBNA1)-targeting probes stimulate interferon-β production by nasopharyngeal carcinoma (NPC) cells to enhance the natural killer cell-mediated cytotoxicity against NPC
Authors: Chen Luo , Liu Xiao Han , Yuen Hei Tung , Cho William C. , Wong Ka-Leung , Lung Hong Lok
Published: March 2024

Introduction: The prevailing histologic subtype of nasopharyngeal carcinoma (NPC) in the endemic regions is non-keratinizing carcinoma which shows almost consistent association with latent infection by Epstein-Barr virus (EBV). Previously our group developed a series of Epstein-Barr virus nuclear antigen 1 (EBNA1)-targeting probes, which can disrupt the EBV latency maintained by EBNA1, and such lytic induction could alert the immune cells.

Methods: Natural killer (NK) cells of the innate immunity play a significant role in controlling EBV infection. In this study, we investigated whether our EBNA1 probes (ZRL5P4 & L2P4) could activate NK cells to eliminate NPC.

Results: Studies of clinical specimens indicated that tumor infiltration of the cytotoxic NK cell subset is a favorable prognostic marker for NPC patients. Furthermore, the cytotoxicity of circulating NK cells derived from NPC patients is equally well the cells from healthy individuals. If those patients’ NK cells can be attracted to infiltrate into the tumors, the tumor burden should be relieved. Indeed, the NPC xenograft with the ZRL5P4 treatment showed heavy mouse NK cell infiltration and tumor size reduction. The essential role of those mouse NK cells was demonstrated. Next, we showed that ZRL5P4 could induce the production of a soluble factor by NPC cells to stimulate the NK cell cytotoxicity. Such NK cell activity was verified in a metastasis NPC model. Mechanistically, the EBNA1 probe treatment could induce the expression of EBV early lytic gene Rta and EBNA1 itself. Both Rta and EBNA1 are known transcription factors to drive the expression of LMP1, the NF-κB signaling was then activated, which turned on the production of the well-known NK cell activation cytokine IFN-β.

Conclusion: Taken together, our results demonstrated that our EBNA1 probes can mobilize NK cells to the tumor sites and activate their anti-tumor activity via the EBV reactivation and stimulation of IFN-β production.

Citation Format: Luo Chen, Xiao Han Liu, Hei Tung Yuen, William C. Cho, Ka-Leung Wong, Hong Lok Lung. Epstein-Barr virus nuclear antigen 1 (EBNA1)-targeting probes stimulate interferon-β production by nasopharyngeal carcinoma (NPC) cells to enhance the natural killer cell-mediated cytotoxicity against NPC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5786.
Abstract 5815: Next-generation RNAi therapeutics: siRNA-loaded exosomes targeting KRAS G12C in non-small cell lung cancer (NSCLC)
Authors: Kim Hyo Kyeong , Choi Yujeong , Kim Kyoung Hwa , Byun Yeongju , Kim Tae Hee , Kim Jae Hwan , An Shung Hyun , Bae DaeHo , Choi MyeongKwan , Chung Jihwa , Kwon Kihwan
Published: March 2024

Background: NSCLC represents the predominant subtype of lung cancer, boasting an overall 5-year survival rate of 26%, a figure that fluctuates based on the disease stage. Within NSCLC, certain cancer gene mutations, notably KRAS G12C, are currently classified as 'undruggable targets,' creating hurdles in achieving effective treatment. The development of innovative anticancer drugs aimed at these challenging targets is expected to present a viable solution to these difficulties.

Methods: Exosomes have garnered attention as an inventive drug delivery system for in vivo gene delivery through systemic injection. We used a new post-loading approach by actively loading KRAS G12C siRNA into exosomes using the shock waves (SWEET: shock wave exosome engineering technology ) in this study. The effect of in vitro and in vivo were tested in NCI-H358 (KRAS G12C mt NSCLC) cells and its xenograft mouse model. The tumor size and weight were measured twice a week.

Results: We developed an exosome-based therapeutic using siRNA to effectively inhibit KRAS G12C, targeting NSCLC. The SWEET platform's post-loading method showed a high efficiency in loading KRAS G12C siRNA into exosomes. The KRAS G12C siRNA-loaded exosomes effectively silenced oncogenic KRAS G12C expression in cancer cells; they inhibited tumor growth when administered intravenously in a NSCLC xenograft mouse model. Remarkably, the anticancer effect of KRAS G12C-loaded exosome was similar to that of Sotorasib, a KRAS G12C mutation targeting anti-cancer drug.

Conclusion: Our study showed KRAS G12C siRNA loaded exosomes were effectively delivered to NSCLC tumor tissue via intravenous (IV) administration. And its anti-cancer effects were very similar to sotorasib, showing potential as a treatment for KRAS G12C mutation-expressing cancer. The effective delivery of siRNA to tumor tissues through exosomes highlights the potential of this technology as a promising approach for developing new RNAi therapeutics for cancer.

Citation Format: Hyo Kyeong Kim, Yujeong Choi, Kyoung Hwa Kim, Yeongju Byun, Tae Hee Kim, Jae Hwan Kim, Shung Hyun An, DaeHo Bae, MyeongKwan Choi, Jihwa Chung, Kihwan Kwon. Next-generation RNAi therapeutics: siRNA-loaded exosomes targeting KRAS G12C in non-small cell lung cancer (NSCLC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5815.
Abstract 5858: Systematic identification of pathways associated with antibody drug conjugate sensitivity in breast cancer
Authors: Wu Bogang , Sun Sheng , Thimmiah Nayana , Nagayama Aiko , Coates James T. , Liu Ting , Thant Win , Bitman Elena , Li David , Doench John , Bardia Aditya , Ellisen Leif W.
Published: March 2024

Antibody drug conjugates (ADCs) are revolutionizing precision therapeutics in oncology. Sacituzumab Govitecan (SG), combining a Topoisomerase I (TOP1) inhibitor payload (SN38) and the tumor-selective antigen TROP2-targeting antibody hRS7, has demonstrated efficacy in challenging cancers including triple negative breast cancer (TNBC). Despite its promising clinical efficacy, the intricacies of sensitivity and resistance mechanisms to SG remain elusive.

To systematically interrogate ADC sensitivity mechanisms, we employed genome-wide CRISPR-Cas9 knockout screening to discover novel regulators influencing SG sensitivity in human TNBC cells. Interactome analysis of top SG sensitizing hits showed clustered pathways of interest, including DNA repair/replication, mTORC1/metabolism, ubiquitin/proteolysis and endosome trafficking/sorting. A top druggable hit sensitizing to SG was PARP1, encoding the poly (ADP-ribose) polymerase 1 that is a key enzyme required for single-strand break repair pathways and for DNA replication fork stability. Furthermore, the synergistic lethality between SG and PARP1 was confirmed in experiments combining SG with PARP inhibitor treatment of TNBC cell lines. To selectively identify SG/ADC-specific genes and pathways, we performed a secondary round of CRISPR knockout and activation screens using a custom library comprising top hits discovered in the primary screen, treating cells in parallel with either SG or cytotoxic payload SN38 alone. Pathway analysis of genes selectively modulating sensitivity to SG but not SN38 revealed novel mediators involved in TROP2 turnover and recycling. We then performed validation and mechanistic studies to elucidate how specific genetic permutations regulate antibody delivery and sensitivity to SG.

In summary, employing a systematic CRISPR screening method, we uncovered numerous novel pathways associated with both resistance and sensitization, playing a role in ADC delivery and target protein turnover. Our current focus involves prioritizing druggable genes and pathways, laying the foundation for proof-of-concept studies that will combine ADCs with specific targeted therapeutics, aiming to enhance tumor-killing efficacy.

Citation Format: Bogang Wu, Sheng Sun, Nayana Thimmiah, Aiko Nagayama, James T. Coates, Ting Liu, Win Thant, Elena Bitman, David Li, John Doench, Aditya Bardia, Leif W. Ellisen. Systematic identification of pathways associated with antibody drug conjugate sensitivity in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5858.
Abstract 5865: Characterization and resistance mechanisms of PNP inhibitor forodesin-resistant cell lines
Authors: Hosono Naoko , Oiwa Kana , Tasaki Toshiki , Nishi Rie , Scott Luigi , O’Connor Owen A. , Yamauchi Takahiro
Published: March 2024

Background: The enzyme purine nucleoside phosphorylase (PNP) is involved in the purine salvage pathway and is present at high levels in lymphoid tissues. Children born with PNP deficiency are known to have significantly reduced T-cell counts but relatively normal B-cell immunity, suggesting PNP as one of the most promising therapeutic targets for T-cell malignancies. Forodesine (For, BCX-1777), a novel PNP inhibitor, was approved in Japan for the treatment of relapsed/refractory PTCL. To understand the cytotoxic effect of For and its mechanism of action, we established a For-resistant (For-R) leukemia cell line and explored the mechanism of resistance.

Methods: We established two For-R T-lymphoblastic leukemia cell lines (CCRF-CEM and MOLT4) through repeated escalating exposure to For and 2’-deoxyguanosined(dGuo). Gene expression analysis was performed to identify the mechanisms of resistance.

Results: For-R cells showed very high resistance compared to parental cells (IC50 value, CEM/CEM-R 4.2nM/>5x105nM, MOLT4/MOLT4-R 8nM/>5x105nM). When cross-resistance was examined in these For-R cells showed mild resistance to cytarabine. The expression of hENT1, a nucleoside transporter, was examined and found to be upregulated in both CEM-R and MOLT4-R cells, while the expression level of deoxycytidine kinase (dCK) was unchanged in both cells. Next, high performance liquid chromatography was used to assess the intracellular dGTP in each parental and its For-R cells. In the parental cells, intracellular dGTP levels increased promptly 4-6 hours after fosteredin administration, whereas in resistant cells, intracellular dGTP levels were higher than before fosteredin administration, and there was little change in dGTP levels after administration.

Conclusion: The established For-R cell line acquired a high resistance to For and showed high intracellular dGTP levels. Imbalance in intracellular GTP levels may be involved in the induction of cell death by For.

IC50 value of each cell lines

Citation Format: Naoko Hosono, Kana Oiwa, Toshiki Tasaki, Rie Nishi, Luigi Scott, Owen A. O’Connor, Takahiro Yamauchi. Characterization and resistance mechanisms of PNP inhibitor forodesin-resistant cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5865.
Abstract 5873: ERα coordinates with squalene synthase to confer statin resistance in lung cancer
Authors: Yang Yi-Fang
Published: March 2024

Statins are widely used to treat hypercholesterolemia by inhibiting hydroxymethylglutaryl coenzyme A reductase (HMGCR). Accumulating evidence suggests that statins also have protective effects against cancer recurrence. However, the role of statins in preventing lung cancer and biomarkers for predicting statin treatment response remains lacking. This study analyzes molecular features that dictate statin sensitivity in lung cancer by correlating large-scale statin sensitivity data and basal gene expression in a collection of 125 lung cancer patients. We identified a gene signature associated with lovastatin sensitivity and showed that gene expression in mesenchymal molecular features, the cholesterol biosynthesis pathway, and estrogen receptor alpha (ERα) signaling were key determinants of lovastatin sensitivity in lung cancer cells. To this end, we further discovered that overexpression of a committed step enzyme in cholesterol biosynthesis farnesyl-diphosphate farnesyltransferase 1 (FDFT1), also known as squalene synthase (SQS), is capable of activating ERα and is associated with increased statin tolerance. In clinical specimens, overexpression of SQS positively correlated with nuclear expression of ERα in lung cancer patients, and the combination of SQS and ERα is a powerful prognostic predictor for lung cancer.

Activation of the SQS-ERα signaling axis and epithelial-to-mesenchymal transition (EMT) status represents two important features in determining statin sensitivity in lung cancer.

Keywords: Statin, cholesterol biosynthesis, squalene synthase, estrogen receptor α, Epithelial-mesenchymal transition

Citation Format: Yi-Fang Yang. ERα coordinates with squalene synthase to confer statin resistance in lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5873.
Abstract 5897: Understanding and targeting fatty acid CoA ligase ACSL4 in human prostate cancer
Authors: Wu Jinjin , Wang Mu-En , Chen Ming , Jeong Pyeong Hwa , Hong Jiyong , Wan Lixin
Published: March 2024

Prostate cancer (PCa) is the most common non-cutaneous malignancy among men. Although localized prostate cancer is curable, recurrence of metastatic castration-resistant prostate cancer (mCRPC) is almost inevitable and is the major cause of death in human PCa. Recent findings from our lab and others demonstrate that RB1 loss drives lineage plasticity, metastasis, and lethality of prostate tumors initiated by PTEN loss. A downstream target upregulated by RB1 loss is acyl CoA synthetase long chain family member 4 (ACSL4), a fatty acid ligase with an essential role in utilization of long chain fatty acids. ACSL4 has been reported to be upregulated in cancers of various histological origins, including prostate cancer, and its high expression is correlated with aggressiveness of cancer. We hypothesize that ACSL4 is a critical downstream effector of RB1 loss-driven prostate tumorigenesis and pharmacological inhibition of ACSL4 could represent a novel therapeutic approach to the treatment of lethal RB1 deficient or ACSL4 overexpressing prostate cancer. Here we aim to develop novel ACSL4 inhibitors for preclinical studies. Through a structure based virtual screening that targeted ATP binding domains of ACSL4, we successfully identified 15 potential ACSL4 inhibitors. To validate the result, we performed an in vitro screening using various parental and isogenic human PCa cell lines, and found that 4 out of 15 compounds effectively inhibited PCa cell proliferation in a dose-response manner and their inhibitory effects positively correlated with cellular levels of ACSL4. Next, we will perform isotope-labeling enzyme activity assays to determine the specificity of the 4 candidate drugs, and PDPK analyses followed by characterizing their in vivo efficacies in preclinical studies, with a final goal to develop a well-validated ACSL4 inhibitor. Successful completion of this work will provide great insights into contributions of ACSL4 to prostate tumorigenesis as well as preclinical data of ACSL4 inhibitors to treat lethal prostate cancer.

Citation Format: Jinjin Wu, Mu-En Wang, Ming Chen, Pyeong Hwa Jeong, Jiyong Hong, Lixin Wan. Understanding and targeting fatty acid CoA ligase ACSL4 in human prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5897.
Abstract 5933: Identifying MC4R-targeted small molecule to investigate MC4R impact on cachexia progression
Authors: Stokes Julia , Tailor Dhanir , Foss Marie , Grau Benedikt , Malhotra Sanjay
Published: March 2024

Background: The melanocortin system participates in energy homeostasis and appetiteregulation. This metabolic system is primarily located in the central nervous system,specifically in the hypothalamus and brainstem region. Within the melanocortin system,there are five established melanocortin receptors (MCR). MCRs are g-protein-coupledreceptors (GPCRs) and when these receptors are activated, they can increase neuronexcitation, regulate neurotransmitter release, regulate synaptic input, and alterconnection and strength. When Melanocortin-4 Receptor (MC4R) plays a critical role inthe progression of multiple metabolic diseases including cachexia. Cachexia is definedas the reduction of fat and lean mass, which is caused not just by lack of appetite, but byinflammatory impact. Cachexia is a symptom seen in numerous chronic diseases fromcancer to mitochondrial dysfunction to autoimmune inflictions. This makes MC4R apotentially strong therapeutic target.

Method: In-silico and high-throughput methods were used to identify small moleculesthat target and inhibit MC4R. For high-throughput screen, Hek293 cells withconstitutively active MC4R tagged with a nanoluciferase were used to identify molecules,specifically with inhibitory qualities. cAMP accumulation and β-arrestin recruitmentassay were used to determine the impact on MC4R functionality.

Results: 4738 small molecules were screened using high-throughput methods. Using a60% cutoff, 21 small molecules were identified as potential MC4R inhibitors. 17 arecurrently under investigation to confirm high-throughput results and identify functionalimpact. Several of these molecules have shown promising potential in vitro and will likelymove forward into in vivo studies.

Conclusion: This study identifies prospective small molecule inhibitors that targetMC4R and may be used as a probe to explore MC4R biology.

Citation Format: Julia Stokes, Dhanir Tailor, Marie Foss, Benedikt Grau, Sanjay Malhotra. Identifying MC4R-targeted small molecule to investigate MC4R impact on cachexia progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5933.
Abstract 5994: Neutrophils internalized through LC3-associated phagocytosis trigger tumor ferroptotic cell death in glioblastoma
Authors: Lu Tong Y. , Yee Patricia P. , Chih Stephen Y. , Aregawi Dawit G. , Glantz Michael J. , Zacharia Brad E. , Wang Hong-Gang , Li Wei
Published: March 2024

Necrosis is commonly found in various solid tumors and predicts worse outcome. Chronic ischemia can initiate tumor necrosis, however, how the damaged tissue further expands is unclear. Previous studies found that neutrophils associate with necrosis and could contribute the necrosis development in glioblastoma (GBM) through transferring myeloperoxidase-containing granules into tumor cells and inducing tumor cell ferroptosis. How the neutrophilic granule transfer occurs is unknown. Here, through an unbiased small molecule screen, we found that statins can inhibit the neutrophil-induced tumor cell death through blocking the neutrophilic content transfer into tumor cells. Surprisingly, we found that neutrophils are engulfed by tumor cells before they are fragmented and release the MPO-containing contents in tumor cells. This process is through LC3-associated phagocytosis (LAP) and can be blocked by inhibiting the Vps34-UVRAG-containing PI3K complex. Inhibition of MPO or depletion of Vps34 in an orthotopic xenograft GBM mouse model showed that necrosis formation is reduced, and the tumor-bearing mice can survive longer. Therefore, this study revealed that the neutrophilic granule transfer is through LAP-mediated neutrophil internalization, which then trigger tumor ferroptotic cell death in glioblastoma. Blocking this process may improve prognosis of GBM.

Citation Format: Tong Y. Lu, Patricia P. Yee, Stephen Y. Chih, Dawit G. Aregawi, Michael J. Glantz, Brad E. Zacharia, Hong-Gang Wang, Wei Li. Neutrophils internalized through LC3-associated phagocytosis trigger tumor ferroptotic cell death in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5994.
Abstract 6051: Discovery of oral SMARCA2 degraders for the treatment of SMARCA4 mutant tumors
Authors: Clemente Jose C. , Harikrishnan Lal , Knight Steve , Samanta Debangshu , Li Zhenwu , Nagilla Rakesh , Kendsersky Nathan , Joshi Shreyas , Orth Peter , Tudor Matt , Deng Qiaolin , Aguilar-Bonavides Clemente , Behshad Elham , Sui Zhihua , Strickland Corey , Jolivette Larry J. , Mohammad Helai P.
Published: March 2024

The paralog enzymes SMARCA2 and SMARCA4 are mutually exclusive members within the SWI/SNF chromatin remodeling complex. This complex plays a crucial role in governing gene expression by altering the chromatin and rendering it accessible to transcription machinery. The process of chromatin remodeling by the SWI/SNF complex is dependent on ATP hydrolysis. Within the complex, either SMARCA2 or SMARCA4 serves as the sole component capable of catalyzing ATP hydrolysis and are thereby essential to the activity of the complex. SMARCA4 has been found to be mutated in various cancer types, including non-small cell lung carcinoma, colon adenocarcinoma, bladder, and endometrial cancer. In cancer cells where SMARCA4 is deleted, the functionality of the SWI/SNF complex and cell survival is dependent on the presence of SMARCA2, thereby resulting in synthetic lethality if SMARCA2 is depleted. Utilizing in vitro and in vivo model systems we have discovered potent, selective, and orally bioavailable heterobifunctional degraders targeting SMARCA2. Our lead molecules exhibit potent and selective degradation of SMARCA2 (DC50 < 10 nM) with no impact on SMARCA4 (DC50 > 1000 nM). Furthermore, a striking selective activity in proliferation assays was observed with SMARCA4 deleted cells exhibiting gIC50 ranging from 1 -10 nM and SMARCA4 WT cells > 1000 nM. Oral administration in mice harboring human cancer cell line xenografts revealed dose-dependent and selective in vivo degradation of SMARCA2. Degradation of SMARCA2 led to significant anti-tumor activity in SMARCA4 mutant NSCLC xenograft models. Together, these data demonstrate a foundation for the development of a best-in-class degrader for the treatment of SMARCA4 deleted cancers.

Citation Format: Jose C. Clemente, Lal Harikrishnan, Steve Knight, Debangshu Samanta, Zhenwu Li, Rakesh Nagilla, Nathan Kendsersky, Shreyas Joshi, Peter Orth, Matt Tudor, Qiaolin Deng, Clemente Aguilar-Bonavides, Elham Behshad, Zhihua Sui, Corey Strickland, Larry J. Jolivette, Helai P. Mohammad. Discovery of oral SMARCA2 degraders for the treatment of SMARCA4 mutant tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6051.
Abstract 6066: An inhibitor of deubiquitinating enzyme UCHL5/USP14, VLX1570, enhances the cytotoxic effects of temsirolimus by suppressing PCNA in uuman renal cell carcinoma
Authors: Kuo Kuan-Lin , Chow Po-Ming , Hsu Chen-Hsun , Liao Shih-Ming , Chiu Yen-Ling , Dong Jun-Ren , Ke Tzu-Yao , Huang Kuo-How
Published: March 2024

Renal cell carcinoma (RCC) is a common type of kidney cancer. The overall 5-year survival rate is 74%, but it drops to only 8% for Stage 4 cancers. Several treatments are available for metastatic RCC, including tyrosine kinase inhibitors, mTOR inhibitors, and immune checkpoint inhibitors. However, these treatments have limited success. VLX1570 is an inhibitor of deubiquitylating enzymes UCHL5/USP14 that is currently in Phase I clinical trials. It has shown promise in various cancer models, but its effects on RCC have not been reported. This study investigated the impact of UCHL5/USP14 expression on tumor progression and patient survival in a clinical cohort. The results showed that VLX1570 induced apoptosis and cell cycle arrest in RCC cells, leading to reduced cell viability. Additionally, VLX1570 synergized with temsirolimus in vitro, likely by inhibiting PCNA. Moreover, the combination treatment suppressed tumor growth in vivo more effectively than either VLX1570 or temsirolimus alone. These findings suggest that UCHL5/USP14 plays a role in RCC progression and prognosis, making it a promising therapeutic target for overcoming drug resistance in this cancer.

Citation Format: Kuan-Lin Kuo, Po-Ming Chow, Chen-Hsun Hsu, Shih-Ming Liao, Yen-Ling Chiu, Jun-Ren Dong, Tzu-Yao Ke, Kuo-How Huang. An inhibitor of deubiquitinating enzyme UCHL5/USP14, VLX1570, enhances the cytotoxic effects of temsirolimus by suppressing PCNA in uuman renal cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6066.
Abstract 6067: Identification of selective CBP degraders with robust preclinical PK, PD, efficacy and safety across solid tumor indications
Authors: Sappal Darshan , Adam Ammar , Ahmad Hafiz , Adams Benjamin , Adhikari Ketaki , Austin Wesley , Bullock Breanna , Bernardo Julie Di , Dixon Thomas , Daniels Danette , Dominici Claudia , Elliot GiNell , Ethell Brian , Gervais Anais , Hossain Md Imran , Huang David , Lahr Dave , Lin Mei Yun , Mayhew David , Mizeracka Karolina , Negretti Solymar , Nguyen Tyler , Prifti Olga , Schiller Shawn , Sherbanee Brenna , Terry David , Ucisik Nihan , Wittenborn Elizabeth , Zhou Qianhe , Zimmerman Mark , La Bonte Laura
Published: March 2024

CREB binding protein (CBP) and E1A binding protein (EP300) are paralog histone acetyltransferases involved in many cellular processes via their activity as transcription factor co-activators. Dysregulation of one or both proteins has been implicated in various cancer types, and functional genomic screens have revealed a bidirectional synthetic lethal relationship between these two paralogs in tumor cells. Due to the high homology between CBP and EP300, identifying selective chemical matter that selectively disrupts the activity of CBP has proven challenging. Small molecule inhibitors targeting the HAT or bromodomain of CBP/EP300 have been developed, however these agents exhibit hematopoietic toxicity resulting from dual inhibition, which limits their therapeutic window. Herein, we describe the PK, PD, and efficacy of selective, potent CBP degraders across various EP300-mutant cancer xenograft models. Our results show deep and sustained CBP degradation, leading to significant tumor growth inhibition in solid tumors. This anti-tumor activity was not associated with significant body weight loss or hematopoietic toxicity. Our CBP-selective protein degraders have the potential to be a first-in-class therapeutic option for patients with tumors harboring EP300 mutations.

Citation Format: Darshan Sappal, Ammar Adam, Hafiz Ahmad, Benjamin Adams, Ketaki Adhikari, Wesley Austin, Breanna Bullock, Julie Di Bernardo, Thomas Dixon, Danette Daniels, Claudia Dominici, GiNell Elliot, Brian Ethell, Anais Gervais, Md Imran Hossain, David Huang, Dave Lahr, Mei Yun Lin, David Mayhew, Karolina Mizeracka, Solymar Negretti, Tyler Nguyen, Olga Prifti, Shawn Schiller, Brenna Sherbanee, David Terry, Nihan Ucisik, Elizabeth Wittenborn, Qianhe Zhou, Mark Zimmerman, Laura La Bonte. Identification of selective CBP degraders with robust preclinical PK, PD, efficacy and safety across solid tumor indications [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6067.
Abstract 6107: Survival differences by socioeconomic status in Merkel cell carcinoma: A retrospective analysis using the National Cancer Database
Authors: Chang Rachel C. , Brunsgaard Elise K. , Reid David
Published: March 2024

Introduction: Merkel cell carcinoma (MCC) is a rare and aggressive skin cancer whose incidence and survival outcomes demonstrate disparities based on patients’ socioeconomic status (SES). This study aims to evaluate the impact of SES on MCC diagnosis age, comorbidity burden, treatment modalities, and survival outcomes using the National Cancer Database.

Methods: We conducted a retrospective analysis of 9742 patients diagnosed with MCC from 2016 to 2020 in the United States. To assess how socioeconomic status influences outcomes, a composite score was created by adding income and education quartile assignments (1, 2, 3, 4), to create new composite SES quartiles of 2-3, 4-5, 6-7, and 8. Patients were stratified into quartiles based on their SES (lowest Q1 to highest Q4). Binomial test was performed for categorical variables and ANOVA was performed for continuous. Survival differences were examined with Cox proportional hazards models and Kaplan-Meier curves.

Results: Patients with lower SES presented with MCC at younger ages, with the average age of patients in the lowest SES Q1 being 73.8 years (95% CI 73.15-74.35) and the highest SES Q4 being 75.0 years (95% CI 74.48-75.46). Patients in SES Q1 also had higher Charson-Deyo scores, indicating more comorbidities than patients in SES Q4 (8.41% vs 5.8%, p < 0.001). They were also more likely to have advanced stage 4 MCC (9.67% vs 7.79%, p < 0.01) compared to patients in SES Q4. When treated with surgery, patients in SES Q1 were more likely to be treated with local tumor excision (14.39% vs 10.83%, p < 0.001) whereas patients in SES Q4 were more likely treated with Mohs surgery (5.02% vs 3.56%, p < 0.01). Survival probabilities for patients SES Q1 were worse at 1 year (82.99% vs 85.81%, p<0.001), 3 years (61.18% vs 68.49%, p < 0.001) and 5 years (45.99% vs 55.09%, p < 0.001) compared to patients in SES Q4.

Conclusion: This study highlights disparities in age at diagnosis, comorbidities, treatment, and survival outcomes in MCC patients based on SES. Patients in lower SES quartiles are diagnosed younger, bear higher comorbidity burdens, and have worse rates of survival.

Citation Format: Rachel C. Chang, Elise K. Brunsgaard, David Reid. Survival differences by socioeconomic status in Merkel cell carcinoma: A retrospective analysis using the National Cancer Database [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6107.
Abstract 611: Discovery of LNX231, a multi-kinase inhibitor mainly target FLT3 with robust in vivo efficacy in FLT3 mutant AML models
Authors: Zhao Lizhi , Hao Guizhou , Deng Rong , Zhang Naihua , Yao Jingchun , Zhu Anguo , Li Guangyan , Wang Enli , Li Zhenyu , Liu Zhong , Zhang Guimin
Published: March 2024

LNX231 is a multi-kinase inhibitor mainly target FLT3, which could both directly kill cancer cells and promote tumor immunity. LNX231 potently inhibits FLT3 activity in biochemical assay, with a 50% inhibitory concentration (IC50) of 3.5 nM, significantly inhibits FLT3-D835Y and FLT3 ITD, the values of IC50 are 20 nM and 4.4 nM. LNX231 inhibits the proliferation of FLT3 mutant AML cell lines via RAS-MARK and JAK-STAT pathway. LNX231 significantly decreases the phosphorylation of STAT5 and ERK in MV-4-11 cells at the high concentration, but has no effect on the phosphorylation of FLT3 and AKT. LNX231 significantly decreases the phosphorylation of FLT3, STAT5 and ERK in MOLM-13 cells at the high concentration, but has no effect on the phosphorylation of AKT. In FLT3 mutated AML models, LNX231 induced sustained tumor shrinkage as a single agent and was well tolerated. At the same dose, LNX231 was more potent than the FDA-approved drug Gilteritinib. In the MC38 tumor-bearing model, the efficacy of LNX231 was better than Sunitinib and Lenvatinib. LNX231 has good oral bioavailability in different species, such as mouse, rat, dog and monkey. DMPK data predicted oral QD dosing in human. It also showed excellent ADMET profile as a pre-clinical candidate. Safety tolerability studies were conducted in mice and dogs. LNX231 has low cardiotoxicity (IC50 of hERG is 25.84 µM) and 5-6 times safety window. In conclusion, we discovered LNX231 as a multi-kinase inhibitor for FLT3 mutated AML.

Citation Format: Lizhi Zhao, Guizhou Hao, Rong Deng, Naihua Zhang, Jingchun Yao, Anguo Zhu, Guangyan Li, Enli Wang, Zhenyu Li, Zhong Liu, Guimin Zhang. Discovery of LNX231, a multi-kinase inhibitor mainly target FLT3 with robust in vivo efficacy in FLT3 mutant AML models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 611.