Cellular Migration Research Articles

Abstract 3936: Altered endosomal pH regulation: molecular mechanisms of oncogenesis and therapeutic dependencies

Abstract ATP6AP1 and ATP6AP2, which we previously identified to be recurrently altered in granular cell tumors (GCTs), encode for accessory proteins of the vacuolar (V)-ATPase, which controls endosomal acidification. The mechanistic basis of how ATP6AP1/AP2 loss of function (LOF) leads to oncogenesis remains to be elucidated. Here, we sought to unravel the molecular mechanisms downstream of ATP6AP1/AP2 inactivation resulting in oncogenesis and identify associated therapeutic dependencies. Using CRISPR/Cas9 technologies, we generated ATP6AP1-knock out (KO), ATP6AP2-KO and non-target (NT) control immortalized Schwann cells, the likeliest cell of origin of GCTs. Compared to NT controls, ATP6AP1/AP2-KOs displayed increased cellular proliferation, migration, and anchorage independent growth. ATP6AP1/AP2-KOs, but not NT controls, demonstrated in vivo tumorigenesis upon subcutaneous implantation in NSG mice. In addition, ATP6AP1/AP2-KOs, compared to NT controls, displayed abnormal bulk endocytic function, evidenced by reduced endocytic cargo delivery to lysosomes in a DQ-Red BSA assay, and increased LC3BII/LC3BI ratio and expression of the autophagy marker GABARAP, indicating altered autophagic flux. ATAC-seq analysis of our cell modes revealed changes in chromatin accessibility upon ATP6AP1/AP2 inactivation, affecting transcription factors (TFs) associated to the Wnt pathway, including LEF/TCF (canonical Wnt) and NFAT (non-canonical Wnt), and TFs associated to autophagy pathways, among others. RNA-sequencing analysis revealed expression changes in key Wnt pathway components upon ATP6AP1/AP2 LOF, such as biphasic modulators (DKK1, DKK2 and SFRP1), secreted ligands (WNT2, WNT9a and WNT7B), transcriptional regulators (TLE1, TLE2, TLE3 and TLE4) and receptors (LGR5, FZD7 and FZD1). Consistent with these findings, ATP6AP1/AP2-KOs displayed upregulation of downstream canonical (MYC, Cyclin D1) and non-canonical (NFATC1, CALM1) Wnt targets at the mRNA and protein levels, and increased sensitivity to pharmacologic inhibition of the Wnt pathway, with significantly lower IC50s to IWR-1, compared to NT controls. Lastly, ATP6AP1/AP2-KOs displayed increased sensitivity to pharmacologic inhibition or induction of autophagy and/or endocytic processes, with lower IC50s to Chloroquine, N-Ethylmaleimide, Torin-1 and Bafilomycin-A1 compared to NT controls. Taken together, we demonstrate that ATP6AP1/AP2 inactivation leads to the acquisition of oncogenic properties in vitro and in vivo, altered endocytosis and autophagy. Furthermore, our findings suggest that ATP6AP1/AP2 LOF results in chromatin accessibility changes leading to activation of an oncogenic transcriptional program with increased signaling via the Wnt pathway. Notably, inactivation of these genes results in unique and previously unknown vulnerabilities, offering potential avenues for therapeutic exploration. Citation Format: Higinio Dopeso, Yingjie Zhu, Laxmi Gusain, Thais Basili, David Brown, Fatemeh Derakhshan, Edaise M. da Silva, Richard Koche, Pierre-Jacques Hamard, Xinyu Guo, Eneda Toska, Elisa DeStanchina, Hong Zhang, Jorge Reis-Filho, Britta Weigelt, Fresia Pareja. Altered endosomal pH regulation: molecular mechanisms of oncogenesis and therapeutic dependencies [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 3936.

Abstract 4582: HDAC6 inhibition reshapes the epigenome of cancer via P300 stabilization

Abstract Introduction: Histone deacetylases (HDACs)are crucial in regulating gene expression, DNA synthesis, and metabolic processes, including cancer, in various cellular environments. The unique structural and functional attributes of class IIb HDAC6 position it as a key player in influencing protein stability and chromatin dynamics. While its role in cancer progression and immunomodulation is well-recognized, the in-depth mechanisms following HDAC6 inactivation, particularly its influence on chromatin remodeling and gene regulation, are not thoroughly understood. This knowledge gap represents a critical area of investigation, given the potential of HDAC6 as a therapeutic target in oncology. This study aims to elucidate HDAC6 inactivation-dependent epigenetic effects of, exploring the possibility to exploit these latter for therapeutic purposes in cancer. This aim includes an examination of the stabilization of the lysine acetyltransferase P300 and its implications for chromatin structure and function. Methods & Results: In this study, ITF3756 and CRISPR/Cas9 were employed to inactivate HDAC6 across a variety of cancer cell lines (Jurkat, MDA 231, HCC1806, 4T1, and B16F10 melanoma). ATAC-seq and H3K27Ac ChIP-seq were used to investigate changes in chromatin accessibility, revealing significant alterations, particularly in introns and distal intergenic regions. Gene Ontology (GO) analysis further supported this alteration in the chromatin landscape, which indicated a differential expression of genes involved in critical cellular processes like cell proliferation, adhesion, migration, and apoptosis. A notable outcome of this study was the stabilization of P300 following ITF3756 treatment, an effect that was paralleled by changes in the expression of critical genes, including AKT1, ITGB3, GAS6, SOX9, NF1, TGFB2, and CASP7. These genes are integral to cellular survival mechanisms, and their modulation emphasizes the role of HDAC6 in cancer cell physiology. Conclusions: This research shows that the chemical or genetic inactivation of HDAC6 impacts cancer cell proliferation and chromatin architecture, underscoring the potential of HDAC6 as a target in cancer therapeutics.. A critical finding of this study is the stabilization of P300, which offers new perspectives on HDAC6's functionality and its role as an epigenetic modifier in cancer cells. This study contributes to the field by suggesting therapeutic strategies focusing on HDAC/HAT pharmacological targeting, thereby advancing our understanding of the role of HDAC6 in regulating cancer cell behavior and epigenetic landscape. Citation Format: Michela Gottardi Zamperla, Barbara Illi, Veronica Barbi, Chiara Cencioni, Stella Gagliardi, Maria Garofalo, Gabriele Antonio Zingale, Irene Pandino, Diego Sbardella, Lina Cipolla, Simone Sabbioneda, Antonella Farsetti, Chiara Ripamonti, Gianluca Fossati, Christian Steinkühler, Sandra Atlante, Carlo Gaetano. HDAC6 inhibition reshapes the epigenome of cancer via P300 stabilization [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 4582.

Abstract 2126: Efficacy and underlying mechanisms of surufatinib in non-small cell lung cancer treatment

Abstract Background: The prevalence and fatality of lung cancer, especially non-small cell lung cancer (NSCLC), highlight the urgency for efficacious therapies. Surufatinib, an inhibitor of tyrosine kinases like VEGF receptors (VEGFR) 1, 2, and 3, Fibroblast growth factor receptor 1 (FGFR1), and CSF-1R, shows potential in augmenting chemotherapy efficacy and reducing adverse effects. Preliminary clinical studies (NCT04922658) have indicated survival benefits for NSCLC patients treated with surufatinib. This investigation seeks to delineate the therapeutic efficacy of surufatinib, correlating clinical benefits with mechanistic insights. Methods: To elucidate mechanisms, proliferation assays (CCK8), migration (scratch assay), and apoptosis (flow cytometry) were conducted in A549 and H1299 cell lines. Angiogenesis and macrophage polarization were examined via vascular junction points and mRNA expression profiling. In nude mice, subcutaneous tumors were induced and treated with the study drugs, with tumor growth and angiogenic markers assessed. Results: In vitro, surufatinib potently inhibited angiogenesis and exerted a dose-dependent suppression of proliferation and colony formation in lung cancer A549 and PC9 cell lines. It also enhanced apoptosis and cell migration. Additionally, surufatinib shifted macrophage polarization towards an M1 phenotype while diminishing M2 macrophages, thereby, contributing to a more robust anti-tumor immune milieu. In vivo studies corroborated these findings, with surufatinib and vinorelbine combination therapy significantly curtailing tumor growth and reducing CD31 expression in tumor tissues, highlighting its potential for substantial therapeutic gains in NSCLC management. Conclusion: Surufatinib achieved notable antitumor effect consistent with clinical findings in NSCLC, effectively inhibiting cellular proliferation and migration, attenuating angiogenesis, and enhancing apoptosis. Significantly, it also modulated macrophage polarization to favor an M1/M2 balance, thus activating the immune response. Therapeutic strategies with surufatinib have underscored augmented antineoplastic efficacy, meriting additional clinical investigations. Citation Format: Yanfang Zheng, Binjie Shan, Meng Wang, Xiaoran Wu, Rui Cai, Feiyu Niu, Yan Yuan, Lu Liu, Xiongjie Zhu. Efficacy and underlying mechanisms of surufatinib in non-small cell lung cancer treatment [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 2126.

Abstract 5420: NLRX1 involves in prostate cancer cell growth, survival and migration

Abstract Prostate cancer (PCa) is one of the most common male cancer and is the second leading cause of death in men. The basic working components about its cause and progression are not surely known in the research as well as the practitioner community. The current curing therapies such as surgery, radiation therapy, cryotherapy, and hormone therapy are not very encouraging. Subsequently, there is a need to investigate new potential targets for focused treatment. NLRX1 (NOD9 or NLR family member X1) is one member among the NLRs and is a non-inflammasome forming NLR sub-group localized in mitochondria. Previous studies showed that NLRX1 is involved as a tumor suppressor in colorectal cancer and hepatocellular carcinoma. However, NLRX1 serves as tumor promoter in breast cancer and head and neck cancer sarcoma. The present study focuses on the role of NLRX1 in prostate cancer cells under stress conditions including serum-free and hydrogen peroxide (H2O2) to understand cell regulation and functions of NLRX1. We used human prostate cancer PC3 and LNCaP cell lines as the models and the following methods, including Annexin V/PI staining for cell viability, BrdU incorporation for cell proliferation, mitoSOX staining for mitochondrial ROS, wound healing assay for cell migration and Boyden chamber for cell invasion. First, we assessed the TCGA database via UCSC Xena and found that prostate cancer tumors have high NLRX1 expression than normal tissues. Next, we knock down the NLRX1 through lentivirus transduction. We found that silencing NLRX1 expression can decrease cell proliferation in PC3 cells. Furthermore, silencing NLRX1 can significantly decrease cell viability under H2O2 in PC3 cells and serum-free condition in both cancer cell lines. In addition, we found that H2O2-induced cell death is reversed by necroptosis inhibitor Nec-1. Moreover, NLRX1 silencing reduces cell migration in both PC3 and LNCaP cells and can inhibit cell invasion in both cell lines at 24 h. These results suggest that NLRX1 is a positive regulator of cell growth, migration and invasion in prostate cancer cells, and NLRX1 provides a cell-protective role in response to H2O2 and serum-free stress. Thus, this study will provide a potential target for the development of a therapeutic strategy for prostate cancer. Citation Format: Wan-Wan Lin, Varsha Rathore. NLRX1 involves in prostate cancer cell growth, survival and migration [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 5420.

Abstract 6537: A novel CCR4 antagonist induces potent anti-tumor response through inhibition of Treg migration into the tumor microenvironment

Abstract Regulatory T cells (Tregs), an immunosuppressive subset of CD4+ T cells, play a vital role in maintaining immune homeostasis by regulating response to self antigens and maintaining tolerance. On the contrary, Tregs infiltrating the tumor microenvironment (TME) impede effective anti-tumor immunity by inhibiting tumor-specific T cell responses and generating a suppressive TME, thus promoting tumor progression. Clinically, Tregs have been proven to play a significant role in resistance to immune checkpoint inhibitors (ICIs) leading to lower response rates. Hence, targeting Tregs would lead to activation of tumor-specific effector T cells and improved long-term anti-tumor immune responses with ICI treatment. CCR4, a chemokine receptor highly expressed on Tregs, spearhead the migration of Tregs and their accumulation in the TME, by responding to the chemokines CCL22 and CCL17 secreted by the inflamed cells in the tumor. CCR4 expression is associated with poor prognosis in various solid tumors. This warrants the therapeutic targeting of CCR4-expressing Tregs to enable effective and durable anti-tumor immune responses. We sought to discover and develop novel small molecule antagonists of CCR4 for use in cancer therapy. Multiple series of CCR4 antagonists were identified by iterative medicinal chemistry efforts and SAR based approach. These compounds were optimized towards attaining required potency, acceptable physicochemical properties, high selectivity and desirable pharmacokinetic profile to achieve anti-tumor activity. Aurigene’s CCR4 antagonists exhibited potent inhibition of CCR4 activity in the reporter-based β-arrestin recruitment assay. This translated well into potent inhibition of CCL22-mediated chemotaxis of CCR4-expressing Tregs in an in vitro cell migration assay. Furthemore, the lead compounds showed desirable drug-like properties and excellent pharmacokinetic exposure in rodents. In an ongoing study in a syngeneic mice tumor model, one of the lead compounds is being evaluated for impact on Treg infiltration, CD8:Treg ratio in the tumor and efficacy. In summary, we have identified novel CCR4 antagonists with desirable drug-like properties that are being evaluated further to identify a clinical candidate. Citation Format: Rashmi Nair, Chandrasekhar Abbineni, Krishna Chaitanya Talluri, Amit A Dhudashiya, Aravind AB, NaveenR Kumar, Ramya R, D Balasubramanyam, Pathur Obanna, Rabin Madhaiyan, DS Samiulla, Girish Daginakatte, Kishore Narayanan, Kavitha Nellore, Shekar Chelur, Susanta Samajdar, Murali Ramachandra. A novel CCR4 antagonist induces potent anti-tumor response through inhibition of Treg migration into the tumor microenvironment [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 6537.

Abstract 2037: Enhanced chemosensitivity to DNA-damaging agents in human high-grade glioma through 2-DG treatment

Abstract Background: Human high-grade gliomas are aggressive brain cancers known for their resistance to treatment. Targeted therapies with single agents have shown limited success, and the presence of tumor heterogeneity complicates treatment. Combining multiple chemotherapeutic agents has emerged as a potential strategy to overcome these challenges. 2-deoxy-D-glucose (2-DG) is a glucose analog known for its ability to disrupt glycolysis, protein folding, and the pentose phosphate pathway. This disruption renders cancer cells more susceptible to further damage from reactive oxygen species and DNA damage. Previous studies have demonstrated synergistic effects when combining 2-DG with chemotherapeutic drugs in various cancers. Our study examines combining 2-DG with DNA-damaging agents for high-grade gliomas to uncover potential synergies, theorizing that this combination enhances cell death and metabolic stress, offering insights for better treatments against these tumors. Methods: The cell proliferation, clonogenic growth, and cell migration assays assessed viability, clonogenic formation, and migration. Additionally, the cell cycle and reactive oxygen species analysis were employed to evaluate cell division, oxidative stress, and antioxidant capacity. The Illumina NovaSeq 6000 platform measured transcript levels, and Liquid Chromatography-High-Resolution Mass Spectrometry analyzed metabolite changes in high-grade glioma cell lines following 2-DG treatment. The Agilent Seahorse Mito Stress Test evaluated alterations in cellular bioenergetics. SYNERGYFINDER 3 quantified synergistic effects of 2-DG with DNA-damaging agents, while the Annexin V-FITC Conjugates and a ROS multiplex assay assessed cell death and metabolic stress. Results: Our findings demonstrate that when used as a single agent, 2-DG induces cell senescence and limits cell migration but is insufficient to trigger cell death. Moreover, 2-DG treatment shifts glioma cells towards oxidative phosphorylation for energy production, elevates ROS levels, and hampers DNA synthesis and repair mechanisms. Our synergy study reveals promising synergistic effects when combining 2-DG with DNA-damaging agents, including 5-FU, Methotrexate, Gemcitabine, and Lomustine. This combined therapy leads to significant ROS generation and increased cell death compared to single-agent treatments. Furthermore, prolonged exposure to 2-DG leads to increased levels of both glucogenic and ketogenic amino acids within glioma cells, potentially serving as an alternative energy source. This finding hints at a prospective therapeutic approach for targeting drug-resistant cells. Conclusions: Our results suggest that the anticancer therapeutic effect of 2-DG is enhanced when used in combination with DNA-damaging agents, indicating this strategy as a potential approach for treating human high-grade glioma. Citation Format: Tracy Miller, Esther Jane, Matthew Halbert, Taylor Gatesman, Stacey Wendell, Dinesh Mohanakrishnan, Sameer Agnihotri, Daniel Premkumar, Ian Pollack. Enhanced chemosensitivity to DNA-damaging agents in human high-grade glioma through 2-DG treatment [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 2037.

Abstract 3035: Bridging the gap: Exploring the roles of ETS- coactivator interactions in promoting prostate cancer

Abstract The ETS family of transcription factors is comprised of 28 members that all share a common C- terminal DNA-binding domain. ETS play essential roles in developmental processes, such as stem cell maintenance, blood vessel formation, and cellular fate. While absent in the normal prostate, four members of the ETS family become expressed in prostate tumors: ETV1, ETV4, ETV5 and ERG. Our lab has previously classified these proteins as oncogenic ETS for their ability to promote cellular migration in normal prostate epithelial RWPE1 cells. Transcription factors may need to interact with additional proteins to serve oncogenic roles. My research explores the interactions between 1) ETV1 and EWS, as well as 2) ERG and p53. Our lab has established that ETV1, ETV4 and ETV5 form essential interactions with EWS, a transcriptional coactivator that promotes ETS activity. In prostate tumors, chromosomal rearrangements result in the N-terminal truncations of ETV1, ETV4 and ETV5. I hypothesize that the EWS interaction domain is retained and that these truncated ETVs will remain oncogenic. Pulldown assays using purified full-length and truncated ETV1 suggests EWS interacts with both N-terminal and C-terminal portions ETV1. I am attempting to express truncated ETV1, ETV4 and ETV5 in RWPE1 cells. Upon stable expression, I will evaluate their interactions with EWS and their ability to promote migration in vitro. To identify putative proteins that bridge EWS to ETV1, immunoprecipitation mass spectrometry will be used. Mutations in p53, a tumor suppressor protein, promote oncogenesis and occur in nearly half of all cancer cases. We hypothesize that mutant p53 interacts with ETS to promote its recruitment to new genomic sites. Previous studies demonstrate that mutant p53 binds ETS2 at a higher affinity than wildtype p53 and we have expanded this list of interacting ETS to include ERG. We seek to explore whether ERG and mutant p53 cooperate to promote oncogenic phenotypes. I successfully cloned wildtype p53, mutant p53 (R248W) and double-mutant p53 (R248W, T81A) into a retroviral backbone. I then transduced RWPE1-Vector and RWPE1-ERG expressing cells to express these constructs. Although additional replicates are needed, it appears that mutant p53 promotes colony formation in both cell types relative to wildtype p53. I plan to validate these observations and generate an appropriate negative control cell line before extending into a mouse model. Through the continuation of this work, I will provide critical insight into the molecular mechanisms by which a subset of ETS factors achieve oncogenic function. We address the contributions of DNA-binding specificity and coactivator interactions in promoting the phenotypes associated with prostate cancer. Citation Format: Kaitlyn M. Mills, Nicholas Downing, Stephanie Metcalf, Peter Hollenhorst. Bridging the gap: Exploring the roles of ETS- coactivator interactions in promoting 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 3035.

The mechanism of the contribution of ICAM-1 to epithelial-mesenchymal transition (EMT) in bladder cancer.

Bladder cancer is one of the most prevalent cancers worldwide. Moreover, if not optimally treated, bladder cancer is a significant burden on healthcare systems due to multiple recurrences which often require more aggressive therapies. Therefore, targeted anti-cancer therapies, developed based on an in-depth understanding of specific proteins and molecular mechanisms, are promising in cancer treatment. Here, for the first time, we presented the new approaches indicating that intracellular adhesion molecule-1 (ICAM-1) may play a potential role in enhancing therapeutic effectiveness for bladder cancer. In the present study, we presented that ICAM-1 expression as well as its regulation in bladder cancer is strongly correlated with the high expression of N-cadherin. Importantly, the presence of N-cadherin and its regulator-TWIST-1 was abolished when ICAM-1 was silenced. We identified also that ICAM-1 is capable of regulating cellular migration, proliferation, and EMT progression in bladder cancer cells via the N-cadherin/SRC/AKT/GSK-3β/β-catenin signaling axis. Therefore, we propose ICAM-1 as a novel metastatic marker for EMT progression, which may also be used as a therapeutic target in bladder cancer.

Abstract 6643: Hyperthermic induction of immunotherapeutic response in in vitro melanoma model

Abstract Immunotherapy has revolutionized the treatment of advanced melanoma, yet challenges persist with non-responders, development of resistance, and dosage concerns. Our strategy to enhance checkpoint inhibitor efficacy is to combine it with hyperthermia. Moderate hyperthermia, 39-45°C, is an interesting anti-neoplastic therapy which induces production of tumor associated antigens rendering tumor sites more amenable to immunotherapy. To investigate temperature-induced alterations on carcinogenic phenotypes in vitro, B16-F10 melanoma cells were grown at 37°C under normal culture conditions, or incubated at 41°C for 2 hours for moderate, febrile hyperthermic induction. Hyperthermia-induced changes were analyzed by trypan blue exclusion assay, scratch wound assay, collection of conditioned media for cytokine array, and protein isolation for Western Blot. Conditioned media from the hyperthermia-treated group showed an inflammatory shift in cytokine and chemokine expression, with increased TNFa and decreased IL-4 expression. Prior studies found the hyperthermia-induced apoptotic effect is directly correlated to endogenous TNFa levels, elucidating a potential molecular mechanism. Treatment for two hours at 41°C decreased proliferation of B16-F10 cells by 62% after 48 hours and 94% after 72 hours. Additionally, hyperthermia decreased cellular migration by 70% after 24 hours. Further evaluation of cellular interactions in important pathways responsible for these hyperthermia-induced changes were investigated via Western blot. Expression of constitutively active MAPK signaling cascade effectors pERK and ERK was decreased by 86% and 50%, respectively, helping to regulate pro-tumorigenic proliferative signaling. Some cancer cells have been demonstrated to resist hyperthermia via mechanisms to inhibit induction of caspase-3, however, in our model caspase-3 expression increased by 31% following 41°C treatment, thus allowing for induction of apoptosis via caspase-3 in this model. Cellular stress may induce these cell death pathways, as well as heat shock responses. Following febrile hyperthermic induction, hsp70 expression increased by 188% compared to cells cultured at 37°C. Hsp70 has a well-established role in supporting tumor-specific immune responses. Induction of hyperthermia in combination with anti-PDL1, anti-PD-1, or IL-15 immunotherapy is currently being evaluated in a C57BL/6 mouse model by our group. These studies aim to assess if hyperthermia augments response to immunotherapies in vivo. Our current works suggests that moderate, non-ablative hyperthermia helps initiate anti-tumor immune responses, assisting in the induction of anti-tumorigenic cell programs and, potentially, the production of additional tumor associated antigens, thereby making it an interesting candidate for combination with immune checkpoint inhibition and other immunotherapeutic approaches. Citation Format: Tara Jarboe, Danielle Quaranto, Nicole R. DeSouza, Kaci Kopec, Jan Geliebter, Raj K. Tiwari, Mark D. Hurwitz. Hyperthermic induction of immunotherapeutic response in in vitro melanoma model [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 6643.

Abstract 1570: Lipid metabolism alterations promote TNBC metastasis and immunotherapy resistance via PD-L1 internalization and signaling

Abstract Programmed death-ligand 1, PD-L1 (CD274), is an immune checkpoint protein upregulated by cancer cells to facilitate immune evasion. PD-L1 also performs oncogenic functions within cancer cells, but the underlying mechanisms of PD-L1 internalization and signaling remain largely unknown. Here, we report a new mechanism whereby altered ceramide metabolism via ceramide synthase 4 (CerS4) drives PD-L1 internalization to potentiate a TGFβ/Shh/β-catenin signaling axis to drive triple-negative breast cancer (TNBC) migration and metastasis. In response to altered ceramide metabolism, we observed that PD-L1 is internalized via clathrin-mediated endocytosis and depends on S278/S279 in its cytoplasmic domain. Once internalized, PD-L1 directly interacts with Caprin-1, an RNA-binding protein previously unassociated with PD-L1 signaling. Through our analysis of clinical specimens, we established a positive association between PD-L1/Caprin-1 interaction and metastatic progression in human TNBC. In terms of mechanism, we determined that the PD-L1/Caprin-1 complex plays a pivotal role in mediating CerS4-dependent cell migration. This complex selectively binds and stabilizes mRNA, resulting in heightened TGFβ/Shh/β-catenin signaling. Conversely, CerS4 restoration in metastatic TNBC cells impaired cellular migration and the interaction between PD-L1 and Caprin-1. Genetic depletion of CerS4 enhanced lung metastasis derived from 4T1 orthotopic allografts and transgenic MMTV-PyMT breast tumors concomitant with PD-L1/Caprin-1 interaction and TGFβ/Shh/β-catenin signaling. Bioinformatics analysis of clinical datasets was used to validate the impact of the CerS4/PD-L1/Caprin-1 axis on metastatic progression in human TNBC. In alignment with enhanced tumor progression, CerS4 depletion in tumors promoted regulatory T-cell infiltration, suggesting an immunosuppressive tumor microenvironment (TME). Treatment with sonidegib, an FDA-approved Hedgehog (Hh) inhibitor, effectively prevented PD-L1 internalization and its interaction with Caprin-1. We hypothesized that sonidegib could synergize with immune checkpoint blockade to sensitize TNBC to immunotherapy, which typically has low response rates. Sonidegib, in combination with αPD-L1 therapy, was significantly more effective in controlling TNBC primary and metastatic tumor growth, especially when Cers4 was downregulated, compared to αPD-L1 monotherapy. Our data also suggested that this potent anti-tumor effect was due to immunotherapy sensitization after combined flow cytometry, multiplexed immunofluorescence, and bulk RNA-sequencing analyses. Altogether, these findings demonstrate a mechanism to define intracellular PD-L1 signaling in response to altered ceramide metabolism, providing a new therapeutic strategy to target TNBC metastasis and improve response to immunotherapy. Citation Format: Wyatt O. Wofford, Jisun Kim, Dosung Kim, Alhaji H. Janneh, Han Gyul Lee, F. Cansu Atilgan, Natalia Oleinik, Elizabeth Hill, Ozge Saatci, Salih Gencer, Paramita Chakraborty, Shikhar Mehrotra, Ozgur Sahin, Besim Ogretmen. Lipid metabolism alterations promote TNBC metastasis and immunotherapy resistance via PD-L1 internalization and signaling [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 1570.

New thiazolidine-2,4-diones as potential anticancer agents and apoptotic inducers targeting VEGFR-2 kinase: Design, synthesis, in silico and in vitro studies

BackgroundVEGFR-2 has emerged as a prominent positive regulator of cancer progression. AimDiscovery of new anticancer agents and apoptotic inducers targeting VEGFR-2. MethodsDesign and synthesis of new thiazolidine-2,4-diones followed by extensive in vitro studies, including VEGFR-2 inhibition assay, MTT assay, apoptosis analysis, and cell migration assay. In silico investigations including docking, MD simulations, ADMET, toxicity, and DFT studies were performed. ResultsCompound 15 showed the strongest VEGFR-2 inhibitory activity with an IC50 value of 0.066 μM. Additionally, most of the synthesized compounds showed anti-proliferative activity against HepG2 and MCF-7 cancer cell lines at the micromolar range with IC50 values ranging from 0.04 to 4.71 μM, relative to sorafenib (IC50 = 2.24 ± 0.06 and 3.17 ± 0.01 μM against HepG2 and MCF-7, respectively). Also, compound 15 showed selectivity indices of 1.36 and 2.08 against HepG2 and MCF-7, respectively. Furthermore, compound 15 showed a significant apoptotic effect and arrested the cell cycle of MCF-7 cells at the S phase. Moreover, compound 15 had a significant inhibitory effect on the ability of MCF-7 cells to heal from. Docking studies revealed that the synthesized thiazolidine-2,4-diones have a binding pattern approaching sorafenib. MD simulations indicated the stability of compound 15 in the active pocket of VEGFR-2 for 200 ns. ADMET and toxicity studies indicated an acceptable pharmacokinetic profile. DFT studies confirmed the ability of compound 15 to interact with VEGFR-2. ConclusionCompound 15 has promising anticancer activity targeting VEGFR-2 with significant activity as an apoptosis inducer.

HIF1A-dependent overexpression of MTFP1 promotes lung squamous cell carcinoma development by activating the glycolysis pathway

IntroductionMitochondrial fission process 1 (MTFP1) is an inner mitochondrial membrane (IMM) protein implicated in the development and progression of various tumors, particularly lung squamous cell carcinoma (LUSC). This study aims to provide a more theoretical basis for the treatment of LUSC. MethodsThrough bioinformatics analysis, MTFP1 was identified as a novel target gene of HIF1A. MTFP1 expression in LUSC was examined using The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), and Proteomics Data Commons (PDC) databases. The Kaplan-Meier plotter (KM plotter) database was utilized to evaluate its correlation with patient survival. Western blot and chromatin immunoprecipitation (ChIP) assays were employed to confirm the regulatory relationship between MTFP1 and HIF1A. Additionally, cell proliferation, colony formation, and migration assays were conducted to investigate the mechanism by which MTFP1 enhances LUSC cell proliferation and metastasis. ResultsOur findings revealed that MTFP1 overexpression correlated with poor prognosis in LUSC patients(P < 0.05). Moreover, MTFP1 was closely associated with hypoxia and glycolysis in LUSC (R = 0.203; P < 0.001, R = 0.391; P < 0.001). HIF1A was identified as a positive regulator of MTFP1. Functional enrichment analysis demonstrated that MTFP1 played a role in controlling LUSC cell proliferation. Cell proliferation, colony formation, and migration assays indicated that MTFP1 promoted LUSC cell proliferation and metastasis by activating the glycolytic pathway (P < 0.05). ConclusionsThis study establishes MTFP1 as a novel HIF1A target gene that promotes LUSC growth by activating the glycolytic pathway. Investigating MTFP1 may contribute to the development of effective therapies for LUSC patients, particularly those lacking targeted oncogene therapies.

Glycoprotein nonmetastatic melanoma protein B impacts the malignant potential of bladder cancer cells through its hem-immunoreceptor tyrosine-based activation motif.

Bladder cancer is one of the most common cancers among men worldwide. Although multiple genomic mutations and epigenetic alterations have been identified, an efficacious molecularly targeted therapy has yet to be established. Therefore, a novel approach is anticipated. Glycoprotein nonmetastatic melanoma protein B (GPNMB) is a type I transmembrane glycoprotein that is highly expressed in various cancers. In this study, we evaluated bladder cancer patient samples and found that GPNMB protein abundance is associated with high-grade tumors, and both univariate and multivariate analyses showed that GPNMB is a prognostic factor. Furthermore, the prognosis of patients with high GPNMB levels was significantly poorer in those with nonmuscle invasive bladder cancer (NMIBC) than in those with muscle invasive bladder cancer (MIBC). We then demonstrated that knockdown of GPNMB in MIBC cell lines with high GPNMB inhibits cellular migration and invasion, whereas overexpression of GPNMB further enhances cellular migration and invasion in MIBC cell lines with originally low GPNMB. Therefore, we propose that GPNMB is one of multiple driver molecules in the acquisition of cellular migratory and invasive potential in bladder cancers. Moreover, we revealed that the tyrosine residue in the hemi-immunoreceptor tyrosine-based activation motif (hemITAM) is required for GPNMB-induced cellular motility.

Anti-ENO1 antibody combined with metformin against tumor resistance: a novel antibody-based platform.

Antibody-based platforms (i.e., ADC) have emerged as one of the most encouraging tools for the cancer resistance caused by cancer stem cells (CSCs) enrichment. Our study might provide a promising therapeutic direction against drug resistance and serve as a potential precursor platform for screening ADC. The cell migration, invasion, drug resistance, and self-renewal were assessed by the cell invasion and migration assay, wound healing assay, CCK-8 assay, colony formation assay, and sphere formation assay, respectively. The expression profiles of CSCs (ALDH+ and CD44+) subpopulations were screened by flow cytometry. The western blot and cell immunofluorescence assay were used to evaluate pathway-related protein expression in both anti-ENO1 antibody, MET combined with DPP/CTX-treated CSCs. In the present study, western blot and flow cytometry verified that anti-ENO1 antibody target the CD44+ subpopulation by inhibiting the PI3K/AKT pathway, while metformin might target the ALDH+ subpopulation through activation of the AMPK pathway and thus reverse drug resistance to varying degrees. Subsequently, in vitro investigation indicated that anti-ENO1 antibody, metformin combined with cisplatin/cetuximab could simultaneously target ALDH+ and CD44+ subpopulations. The combination also inhibited the CSCs proliferation, migration, invasion, and sphere formation; which may result in overcoming the drug resistance. Then, molecular mechanism exploration verified that the anti-ENO1 antibody, metformin combined with cisplatin/cetuximab inhibited the Wnt/β-catenin signaling. The study preliminarily revealed anti-ENO1 antibody combined with metformin could overcome drug resistance against CSCs by inhibiting the Wnt//β-catenin pathway and might serve as a potential precursor platform for screening ADC. More importantly, it is reasonably believed that antibody-based drug combination therapy might function as an encouraging tool for oncotherapy.

Overexpression of TRPV1 activates autophagy in human lens epithelial cells under hyperosmotic stress through Ca2+-dependent AMPK/mTOR pathway.

To explore whether autophagy functions as a cellular adaptation mechanism in lens epithelial cells (LECs) under hyperosmotic stress. LECs were treated with hyperosmotic stress at the concentration of 270, 300, 400, 500, or 600 mOsm for 6, 12, 18, 24h in vitro. Polymerase chain reaction (PCR) was employed for the mRNA expression of autophagy-related genes, while Western blotting detected the targeted protein expression. The transfection of stub-RFP-sens-GFP-LC3 autophagy-related double fluorescence lentivirus was conducted to detect the level of autophagy flux. Scanning electron microscopy was used to detect the existence of autolysosome. Short interfering RNA of autophagy-related gene (ATG) 7, transient receptor potential vanilloid (TRPV) 1 overexpression plasmid, related agonists and inhibitors were employed to their influence on autophagy related pathway. Flow cytometry was employed to test the apoptosis and intracellular Ca2+ level. Mitochondrial membrane potential was measured by JC-1 staining. The cell counting kit-8 assay was used to calculate the cellular viability. The wound healing assay was used to evaluate the wound closure rate. GraphPad 6.0 software was utilized to evaluate the data. The hyperosmotic stress activated autophagy in a pressure- and time-dependent manner in LECs. Beclin 1 protein expression and conversion of LC3B II to LC3B I increased, whereas sequestosome-1 (SQSTM1) protein expression decreased. Transient Ca2+ influx was stimulated caused by hyperosmotic stress, levels of mammalian target of rapamycin (mTOR) phosphorylation decreased, and the level of AMP-activated protein kinase (AMPK) phosphorylation increased in the early stage. Based on this evidence, autophagy activation through the Ca2+-dependent AMPK/mTOR pathway might represent an adaptation process in LECs under hyperosmotic stress. Hyperosmotic stress decreased cellular viability and accelerated apoptosis in LECs and cellular migration decreased. Inhibition of autophagy by ATG7 knockdown had similar results. TRPV1 overexpression increased autophagy and might be crucial in the occurrence of autophagy promoted by hyperosmotic stress. A combination of hyperosmotic stress and autophagy inhibition may be a promising approach to decrease the number of LECs in the capsular bag and pave the way for improving prevention of posterior capsular opacification and capsular fibrosis.

Matrix confinement modulates 3D spheroid sorting and burst-like collective migration

While it is known that cells with differential adhesion tend to segregate and preferentially sort, the physical forces governing sorting and invasion in heterogeneous tumors remain poorly understood. To investigate this, we tune matrix confinement, mimicking changes in the stiffness and confinement of the tumor microenvironment, to explore how physical confinement influences individual and collective cell migration in 3D spheroids. High levels of confinement lead to cell sorting while reducing matrix confinement triggers the collective fluidization of cell motion. Cell sorting, which depends on cell-cell adhesion, is crucial to this phenomenon. Burst-like migration does not occur for spheroids that have not undergone sorting, regardless of the degree of matrix confinement. Using computational Self-Propelled Voronoi modeling, we show that spheroid sorting and invasion into the matrix depend on the balance between cell-generated forces and matrix resistance. The findings support a model where matrix confinement modulates 3D spheroid sorting and unjamming in an adhesion-dependent manner, providing insights into the mechanisms of cell sorting and migration in the primary tumor and toward distant metastatic sites. Statement of significanceThe mechanical properties of the tumor microenvironment significantly influence cancer cell migration within the primary tumor, yet how these properties affect intercellular interactions in heterogeneous tumors is not well understood. By utilizing calcium and calcium chelators, we dynamically alter collagen-alginate hydrogel stiffness and investigate tumor cell behavior within co-culture spheroids in response to varying degrees of matrix confinement. High confinement is found to trigger cell sorting while reducing confinement for sorted spheroids facilitates collective cell invasion. Notably, without prior sorting, spheroids do not exhibit burst-like migration, regardless of confinement levels. This work establishes that matrix confinement and intercellular adhesion regulate 3D spheroid dynamics, offering insights into cellular organization and migration within the primary tumor.

Butyrate attenuates the stemness of lung cancer cells through lysosome Fe2+- and SLC7A11-mediated ferroptosis

Cancer stem cells (CSCs) are considered key contributors to tumor progression, and ferroptosis has been identified as a potential target for CSCs. We have previously shown that butyrate enhances the ferroptosis induced by erastin in lung cancer cell, this study aimed to investigate the impact of butyrate on the progression of lung CSCs. To investigate these effects, we constructed a series of in vitro experiments, including 3D non-adherent sphere-formation, cytometry analysis, assessment of CSC marker expression, cell migration assay, and in vivo tumorigenesis analyses. Additionally, the influence of butyrate on chemotherapeutic sensitivity were determined through both in vitro and in vivo experiments. Mechanistically, immunofluorescence analysis was employed to examine the localization of biotin-conjugated butyrate. We identified that butyrate predominantly localized in the lysosome and concurrently recruited Fe2+ in lysosome. Moreover, butyrate reduced the stability of SLC7A11 protein stability in lung cancer cells through ubiquitination and proteasome degradation. Importantly, the effects of butyrate on lung CSCs were found to be dependent on lysosome Fe2+- and SLC7A11-mediated ferroptosis. In summary, our results demonstrate that butyrate could induce the ferroptosis in lung CSCs by recruiting Fe2+ in lysosome and promoting the ubiquitination-lysosome degradation of SLC7A11 protein.

Matrix Resistance Toward Proteolytic Cleavage Controls Contractility-Dependent Migration Modes During Angiogenic Sprouting.

Tissue homeostasis and disease states rely on the formation of new blood vessels through angiogenic sprouting, which is tightly regulated by the properties of the surrounding extracellular matrix. While physical cues, such as matrix stiffness or degradability, have evolved as major regulators of cell function in tissue microenvironments, it remains unknown whether and how physical cues regulate endothelial cell migration during angiogenesis. To investigate this, a biomimetic model of angiogenic sprouting inside a tunable synthetic hydrogel is created. It is shown that endothelial cells sense the resistance of the surrounding matrix toward proteolytic cleavage and respond by adjusting their migration phenotype. The resistance cells encounter is impacted by the number of covalent matrix crosslinks, crosslink degradability, and the proteolytic activity of cells. When matrix resistance is high, cells switch from a collective to an actomyosin contractility-dependent single cellular migration mode. This switch in collectivity is accompanied by a major reorganization of the actin cytoskeleton, where stress fibers are no longer visible, and F-actin aggregates in large punctate clusters. Matrix resistance is identified as a previously unknown regulator of angiogenic sprouting and, thus, provides a mechanism by which the physical properties of the matrix impact cell migration modes through cytoskeletal remodeling.

In vitro and in vivo assessment of gallic acid-chitosan/polycaprolactone conjugate electrospun nanofibers for wound healing

The development of innovative multifunctional wound healing materials based on natural bioactives has attracted a great deal of attention in recent years due to their ability to potentiate the healing process and minimize the challenges linked with conventional wound dressings. The current study demonstrates the development and evaluation of a novel nanofibrous wound healing mat made of Gallic acid-chitosan conjugate (GAC) incorporated within a polycaprolactone (PCL) matrix using an electrospinning technique. The GAC conjugate was synthesized by green synthesis using a free radical polymerization reaction to improve the chitosan's free radical scavenging properties. FTIR, DSC, XRD, and UV spectral analysis characterized the formation of GAC conjugate. The red shift observed in the UV spectrum suggested alterations in electronic transitions resulting from the creation of covalent bonds between Chitosan (CA) and Gallic acid (GA). The appearance of broader and weaker peaks in DSC and the reduced crystallinity in XRD spectrum, signify structural modifications, thereby providing valuable insights into the interaction and structural changes occurring in the GAC conjugates.The SEM image revealed a porous flake-like structural network of GAC conjugate due to the reduced intermolecular hydrogen bonding between them. The functional layer of the nanofibrous mat was produced by electrospinning GAC conjugate with polycaprolactone (PCL) to provide mechanical integrity to the nanofibrous mat. The electrospun nanofibers were characterized using FTIR, DSC, and SEM and evaluated for cell cytotoxicity, angiogenesis, and in vivo wound healing potential in female Wistar rats. The FTIR spectra confirmed the presence of GAC conjugate in the nanofibers, validating the conjugation process. The results demonstrated the successful incorporation of GAC conjugate within the PCL nanofibrous mat, thereby confirming the improvement in the biological properties of the mats. The nanofibrous mat showed angiogenesis activity in the yolk sac membrane assay confirming the property of nanofibers to facilitate cellular adhesion, migration and promotion of angiogenesis with no cytotoxic effect on the viability of mouse stromal cells. On the sixteenth day of therapy, wounds dressed with GAC/PCL nanofibrous mat exhibited a significant improvement in the percent wound closure (94.43%) as compared to the control group (p < 0.05). These results supported the application of GAC/PCL as a novel biomaterial for wound dressing to accelerate the process of wound healing.

Exosomes Derived from Mouse Breast Carcinoma Cells Facilitate Diabetic Wound Healing.

Exosomes derived from breast cancer have been reported to play a role in promoting cell proliferation, migration, and angiogenesis, which has the potential to accelerate the healing process of diabetic wounds. The aim of this investigation was to examine the function of exosomes originating from 4T1 mouse breast carcinoma cells (TEXs) in the process of diabetic wound healing. The assessment of primary mouse skin fibroblastscell proliferation and migration was conducted through the utilization of CCK-8 and wound healing assays, while the tube formation of HUVECs was evaluated by tube formation assay. High-throughput sequencing, RT-qPCR and cell experimentswere used to detect the roles ofmiR-126a-3pin HUVECsfunctions in vitro. The in vivo study employed a model of full-thickness excisional wounds in diabetic subjects to explore the potential therapeutic benefits of TEXs. Immunohistochemical and immunofluorescent techniques were utilized to evaluate histological changes in skin tissues. The findings suggested that TEXs facilitate diabetic wound healing through the activation of cell migration, proliferation, and angiogenesis. An upregulation of miR-126a-3p has been observed in TEXs, and it has demonstrated efficient transferability from 4T1 cells to HUVEC cells. The activation of the PI3K/Akt pathway has been attributed to miR-126a-3p derived from TEXs. The promotion of chronic wound healing can be facilitated by TEXs through the activation of cellular migration, proliferation, and angiogenesis. The activation of the PI3K/Akt pathway by miR-126a-3p originating from TEXs has been discovered, indicating a potential avenue for enhancing the regenerative capabilities of wounds treated with TEXs.