Cellular Survival Research Articles

LPA5-Dependent signaling regulates regeneration of the intestinal epithelium following irradiation.

Lysophosphatidic acid (LPA) is a bioactive lipid molecule that regulates a wide array of cellular functions, including proliferation, differentiation, and survival, via activation of cognate receptors. The LPA5 receptor is highly expressed in the intestinal epithelium, but its function in restoring intestinal epithelial integrity following injury has not been examined. Here, we use a radiation-induced injury model to study the role of LPA5 in regulating intestinal epithelial regeneration. Control mice (Lpar5f/f) and mice with an inducible, epithelial cell-specific deletion of Lpar5 in the small intestine (Lpar5IECKO) were subjected to 10 Gy total body X-ray irradiation and analyzed during recovery. Repair of the intestinal mucosa was delayed in Lpar5IECKO mice with reduced epithelial proliferation and increased crypt cell apoptosis. These effects were accompanied by reduced numbers of OLFM4+ intestinal stem cells (ISCs). The effects of LPA5 on ISCs were corroborated by studies using organoids derived from Lgr5-lineage tracking reporter mice with deletion of Lpar5 in Lgr5+-stem cells (Lgr5Cont or Lgr5ΔLpar5). Irradiation of organoids resulted in fewer numbers of Lgr5ΔLpar5 organoids retaining Lgr5+-derived progenitor cells compared with Lgr5Cont organoids. Finally, we observed that impaired regeneration in Lpar5IECKO mice was associated with reduced numbers of Paneth cells and decreased expression of Yes-associated protein (YAP), a critical factor for intestinal epithelial repair. Our study highlights a novel role for LPA5 in regeneration of the intestinal epithelium following irradiation and its effect on the maintenance of Paneth cells that support the stem cell niche.NEW & NOTEWORTHY We used mice lacking expression of the lysophosphatidic acid receptor 5 (LPA5) in intestinal epithelial cells and intestinal organoids to show that the LPA5 receptor protects intestinal stem cells and progenitors from radiation-induced injury. We show that LPA5 induces YAP signaling and regulates Paneth cells.

The Intricate Balance between Life and Death: ROS, Cathepsins, and Their Interplay in Cell Death and Autophagy.

Cellular survival hinges on a delicate balance between accumulating damages and repair mechanisms. In this intricate equilibrium, oxidants, currently considered physiological molecules, can compromise vital cellular components, ultimately triggering cell death. On the other hand, cells possess countermeasures, such as autophagy, which degrades and recycles damaged molecules and organelles, restoring homeostasis. Lysosomes and their enzymatic arsenal, including cathepsins, play critical roles in this balance, influencing the cell's fate toward either apoptosis and other mechanisms of regulated cell death or autophagy. However, the interplay between reactive oxygen species (ROS) and cathepsins in these life-or-death pathways transcends a simple cause-and-effect relationship. These elements directly and indirectly influence each other's activities, creating a complex web of interactions. This review delves into the inner workings of regulated cell death and autophagy, highlighting the pivotal role of ROS and cathepsins in these pathways and their intricate interplay.

Effects of nucleoside analogues, lipophilic prodrugs and elaidic acids on core signaling pathways in cancer cells

Objectives Nucleoside analogs such as gemcitabine (GEM; dFdC) and cytarabine (Ara-C) require nucleoside transporters to enter cells, and deficiency in equilibrative nucleoside transporter 1 (ENT1) can lead to resistance to these drugs. To facilitate transport-independent uptake, prodrugs with a fatty acid chain attached to the 5’-position of the ribose group of gemcitabine or cytarabine were developed (CP-4126 and CP-4055, respectively). As antimetabolites can activate cellular survival pathways, we investigated whether the prodrugs or their side-chains had similar or decreased effects. Methods Two cell lines A549 (non-small cell lung cancer) and WiDr (colon cancer cells) were exposed for 2-24hr to IC50 concentrations of GEM, Ara-C, CP-4126, CP4055 and elaidic acid (EA) concentrations corresponding to the CP-4126 and CP-4055 IC50. Cells were harvested and analyzed for proteins in cell survival pathways (p-AKT/AKT, p-ERK/ERK, p-P38/P38, GSK-3β/pGSK-3β) by using Western Blotting. Results All drugs and their derivatives showed time- and cell-line-dependent effects. In A549 cells, GEM, CP-4126 and EA-4126 decreased the p-AKT/AKT ratio at 2 and 24 hr. For the p-ERK/ERK ratio, GEM, EA-4126, Ara-C, CP-4045 and EA-4055 exposure led to an increase after 6 hr in A549 cells. Interestingly, Ara-C, CP-4055 and EA-4055 decreased p-ERK/ERK ratio in WiDr cells after 4 hr. In A549 cells, the p-GSK-3β/GSK-3β ratio decreased after exposure to Ara-C and CP-4055 but in WiDr cells increased after 24 hr. In A549 cells treatment with Ara-C, CP-4055 and EA-4126 decreased the p-P38/P38 after 6 hr. Conclusions The findings suggest that both parent drugs, prodrugs, and the EA chain influence cell survival and signaling pathways.

USP7 Deregulation Impairs S Phase Specific DNA Repair after Irradiation in Breast Cancer Cells.

The ubiquitin specific protease 7 (USP7) is a deubiquitinating enzyme with numerous substrates. Aberrant expression of USP7 is associated with tumor progression. This study aims to investigate how a deregulated USP7 expression affects chromosomal instability and prognosis of breast cancer patients in silico and radiosensitivity and DNA repair in breast cancer cells in vitro. The investigations in silico were performed using overall survival and USP7 mRNA expression data of breast cancer patients. The results showed that a high USP7 expression was associated with increased chromosomal instability and decreased overall survival. The in vitro experiments were performed in a luminal and a triple-negative breast cancer cell line. Proliferation, DNA repair, DNA replication stress, and survival after USP7 overexpression or inhibition and irradiation were analyzed. Both, USP7 inhibition and overexpression resulted in decreased cellular survival, distinct radiosensitization and an increased number of residual DNA double-strand breaks in the S phase following irradiation. RAD51 recruitment and base incorporation were decreased after USP7 inhibition plus irradiation and more single-stranded DNA was detected. The results show that deregulation of USP7 activity disrupts DNA repair in the S phase by increasing DNA replication stress and presents USP7 as a promising target to overcome the radioresistance of breast tumors.

Structure-based multitargeted docking screening, pharmacokinetics, DFT, and dynamics simulation studies reveal mitoglitazone as a potent inhibitor of cellular survival and stress response proteins of lung cancer.

Lung cancer is a disease in which lung cells grow abnormally and uncontrollably, and the cause of it is direct smoking, secondhand smoke, radon, asbestos, and certain chemicals. The worldwide leading cause of death is lung cancer, which is responsible for more than 1.8 million deaths yearly and is expected to rise to 2.2 million by 2030. The most common type of lung cancer is non-small cell lung cancer (NSCLC), which accounts for about 80% and small cell lung cancer (SCLC), which is more aggressive than NSCLC and is often diagnosed later and accounts for 20% of cases. The global concern for lung cancer demands efficient drugs with the slightest chance of developing resistance, and the idea of multitargeted drug designing came up with the solution. In this study, we have performed multitargeted molecular docking studies of Drug Bank compounds with HTVS, SP and XP algorithms followed by MM\GBSA against the four proteins of lung cancer cellular survival and stress responses, which revealed Mitoglitazone as a multitargeted inhibitor with a docking and MM\GBSA score ranging from - 5.784 to - 7.739 kcal/mol and - 25.81 to - 47.65kcal/mol, respectively. Moreover, we performed pharmacokinetics studies and QM-based DFT analysis, showing suitable candidate and interaction pattern analysis revealed the most count of interacting residues was 4GLY, 5PHE, 6ASP, 6GLU, 6LYS, and 6THR. Further, the results were validated with SPC water model-based MD simulation for 100ns in neutralised condition, showing the cumulative deviation and fluctuation < 2Å with many intermolecular interactions. The whole analysis has suggested that Mitoglitazone can be used as a multitargeted inhibitor against lung cancer-however, experimental studies are needed before human use.

The role of Na+-coupled bicarbonate transporters (NCBT) in health and disease.

Cellular and organism survival depends upon the regulation of pH, which is regulated by highly specialized cell membrane transporters, the solute carriers (SLC) (For a comprehensive list of the solute carrier family members, see: https://www.bioparadigms.org/slc/ ). The SLC4 family of bicarbonate (HCO3-) transporters consists of ten members, sorted by their coupling to either sodium (NBCe1, NBCe2, NBCn1, NBCn2, NDCBE), chloride (AE1, AE2, AE3), or borate (BTR1). The ionic coupling of SLC4A9 (AE4) remains controversial. These SLC4 bicarbonate transporters may be controlled by cellular ionic gradients, cellular membrane voltage, and signaling molecules to maintain critical cellular and systemic pH (acid-base) balance. There are profound consequences when blood pH deviates even a small amount outside the normal range (7.35-7.45). Chiefly, Na+-coupled bicarbonate transporters (NCBT) control intracellular pH in nearly every living cell, maintaining the biological pH required for life. Additionally, NCBTs have important roles to regulate cell volume and maintain salt balance as well as absorption and secretion of acid-base equivalents. Due to their varied tissue expression, NCBTs have roles in pathophysiology, which become apparent in physiologic responses when their expression is reduced or genetically deleted. Variations in physiological pH are seen in a wide variety of conditions, from canonically acid-base related conditions to pathologies not necessarily associated with acid-base dysfunction such as cancer, glaucoma, or various neurological diseases. The membranous location of the SLC4 transporters as well as recent advances in discovering their structural biology makes them accessible and attractive as a druggable target in a disease context. The role of sodium-coupled bicarbonate transporters in such a large array of conditions illustrates the potential of treating a wide range of disease states by modifying function of these transporters, whether that be through inhibition or enhancement.

Impaired autophagy following ex vivo cooling of simulated hypothermic temperatures in peripheral blood mononuclear cells from young and older adults

Hypothermia is a critical consequence of extreme cold exposure that increases the risk of cold-related injury and death in humans. While the initiation of cytoprotective mechanisms including the process of autophagy and the heat shock response (HSR) is crucial to cellular survival during periods of stress, age-related decrements in these systems may underlie cold-induced cellular vulnerability in older adults. Moreover, whether potential sex-related differences in autophagic regulation influence the human cold stress response remain unknown. We evaluated the effect of age and sex on mechanisms of cytoprotection (autophagy and the HSR) and cellular stress (apoptotic signaling and the acute inflammatory response) during ex vivo hypothermic cooling. Venous blood samples from 20 healthy young (10 females; mean [SD]: 22 [2] years) and 20 healthy older (10 females; 66 [5] years) adults were either isolated immediately (baseline) for peripheral blood mononuclear cells (PBMCs) or exposed to water bath temperatures maintained at 37, 35, 33, 31, or 4 °C for 90 min before PBMC isolation. Proteins associated with autophagy, apoptosis, the HSR, and inflammation were analyzed via Western blotting. Indicators of autophagic initiation and signaling (LC3, ULK1, and beclin-2) and the HSR (HSP90 and HSP70) increased when exposed to hypothermic temperatures in young and older adults (all p ≤ 0.007). Sex-related differences were only observed with autophagic initiation (ULK1; p = 0.015). However, despite increases in autophagic initiators ULK1 and beclin-2 (all p < 0.001), this was paralleled by autophagic dysfunction (increased p62) in all groups (all p < 0.001). Further, apoptotic (cleaved-caspase-3) and inflammatory (IL-6 and TNF-α) signaling increased in all groups (all p < 0.001). We demonstrated that exposure to hypothermic conditions is associated with autophagic dysfunction, irrespective of age or sex, although there may exist innate sex-related differences in cytoprotection in response to cold exposure as evidenced through altered autophagic initiation.

Swollen Feet: Considering the Paradoxical Roles of Interleukins in Nephrotic Syndrome.

Interleukins are a family of 40 bioactive peptides that act through cell surface receptors to induce a variety of intracellular responses. While interleukins are most commonly associated with destructive, pro-inflammatory signaling in cells, some also play a role in promoting cellular resilience and survival. This review will highlight recent evidence of the cytoprotective actions of the interleukin 1 receptor (IL-1R)- and common gamma chain receptor (IL-Rγc)-signaling cytokines in nephrotic syndrome (NS). NS results from the injury or loss of glomerular visceral epithelial cells (i.e., podocytes). Although the causes of podocyte dysfunction vary, it is clear that pro-inflammatory cytokines play a significant role in regulating the propagation, duration and severity of disease. Pro-inflammatory cytokines signaling through IL-1R and IL-Rγc have been shown to exert anti-apoptotic effects in podocytes through the phosphoinositol-3-kinase (PI-3K)/AKT pathway, highlighting the potential utility of IL-1R- and IL-Rγc-signaling interleukins for the treatment of podocytopathy in NS. The paradoxical role of interleukins as drivers and mitigators of podocyte injury is complex and ill-defined. Emerging evidence of the cytoprotective role of some interleukins in NS highlights the urgent need for a nuanced understanding of their pro-survival benefits and reveals their potential as podocyte-sparing therapeutics for NS.

Abstract 3349: Identification of new potential vulnerabilities for differentiation-based therapeutic strategies against osteosarcoma

Abstract Osteosarcoma (OS), a mesenchymal bone tumor affecting mainly children and adolescents is characterized by a particularly aggressive behavior, with 20% of patients showing lung metastasis already at diagnosis. Current OS treatment strategies rely on multi-drug chemotherapy, and the prognosis for metastatic cases remains grim, underscoring the pressing need for novel therapeutic approaches. OS is considered a differentiation-related disorder, stemming from the inability of mesenchymal stem cells or osteoblastic progenitors to progress towards terminal differentiation. In our study we explored the impact of targeting ZEB1, a transcription factor known to play a pivotal role in maintaining mesenchymal and stemness characteristics in cancer, on OS cells. We employed CRISPR-Cas9 and shRNA interference techniques to inhibit ZEB1 expression in mouse immune competent OS models. In vitro, ZEB1 deficiency significantly diminished the stemness potential of OS cells, as assessed by spheroid formation assays, while promoting osteogenic differentiation. In vivo, ZEB1 deletion in OS cells led to a significant reduction in primary tumor growth. Tumors originating from ZEB1 KO cells exhibited a more differentiated morphology and higher extracellular matrix deposition compared to controls. Intriguingly, the absence of ZEB1 in tumor cells also influenced the immune infiltrate, with ZEB1-deficient tumors showing significantly fewer pro-tumoral CD206+ M2-like macrophages. This observation is in line with the significant down-modulation of CCL2 expression we detected in ZEB1 KO cells. When injected intravenously, ZEB1-deficient cells produced fewer and smaller lung metastases than control cells. Transcriptional changes induced by ZEB1 deletion were investigated by gene expression profile (GEP) and identified 849 down-regulated and 1093 up-regulated genes in ZEB1 knockout (KO) clones versus ZEB1-competent controls. Gene set enrichment analysis showed a down-modulation of pathways related to cellular proliferation and survival, such as MTORC1 signaling, MYC targets, GM2 checkpoint, E2F targets and oxidative phosphorylation in the absence of ZEB1. Single gene analysis identified among the most up-regulated genes in ZEB1-deficient cells Sfrp1, a negative regulator of the WNT/b-CAT pathway, which in turn regulates MYC, whose pathway is indeed repressed in ZEB1 KO cells. We hypothesize that a high expression of SFRP1 could vicariate the effects of ZEB1 inhibition on OS cell stemness, differentiation state, and in vivo aggressiveness, and therefore could act as a tumor suppressor, which could be potentially exploited for therapeutic strategies. Citation Format: Caterina Cascini, Daniele Lecis, Valeria Cancila, Katia Scotlandi, Claudio Tripodo, Mario P. Colombo, Claudia Chiodoni. Identification of new potential vulnerabilities for differentiation-based therapeutic strategies against osteosarcoma [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 3349.

Abstract 1873: AST-05X: A novel GCN2 inhibitor as a promising anti-cancer approach for sarcoma

Abstract Background Integrated stress response (ISR) is an adaptive signaling pathway that responds to stress and plays an important role in cell fate determination. This pathway enables cellular adaptation and survival under stress conditions by activating specific genes that reduce protein synthesis. Tumors exist in a state characterized by heightened intrinsic and extrinsic stress, heavily relying on a balanced ISR to manage the metabolic demands for rapid growth. ISR (Integrated Stress Response) consists of four major kinases: GCN2, PERK, HRI, and PKR. GCN2 is activated by stress due to amino acid deprivation. Amino acids are crucial for cell survival, and cancer cells, require higher amounts than normal cells, particularly depending on conditionally essential amino acids like glutamine, asparagine, and arginine. GCN2 activation acts as a key mechanism for cancer cells to overcome amino acid deficiencies, making GCN2 a potential target, especially in conjunction with anticancer drugs like asparaginase. In this study, we aimed to identify a potential GCN2 inhibitor to explore a promising anti-cancer approach in sarcoma, a rare cancer with no new therapeutic alternatives. Method The activity verification of ISR kinases was characterized using in-vitro enzyme assays. In-vitro panel assays were employed to determine the selectivity profiling for oncology kinases. The modulation of the ISR pathway was validated using a sarcoma cell line (HT-1080) and a cell line derived from sarcoma patients. Western blot or ELISA assays were employed to measure phospho-GCN2, ATF4, phospho-eIF2a, and CHOP under both basal conditions and amino acid starvation conditions. Gene expression profiling (GEP) of sarcoma patient tissue samples(n=17) was conducted through RNA sequencing (RNAseq) analysis. Results AST-05X is a selective and potent GCN2 inhibitor. AST-05X inhibits the expression of GCN2 and ISR downstream factors (p-eIF2a, ATF, CHOP) in vitro cell-based experiments under amino acid deprivation. In addition, based on the results of ISR-related gene expression profiling GEP analysis, we identified potential CDx biomarkers for evaluating the diagnosis and treatment response of sarcoma. Conclusion This study is currently investigating the efficacy of the drug in sarcoma patient-derived xenograft models. AST-05X is a GCN2 inhibitor that has the potential to validate the inhibition of GCN2 as a promising anti-cancer approach for sarcoma, a rare cancer with limited therapeutic alternatives. Citation Format: Youngki Choi, Jinback Lim, Hyo-Hyun Park, Jinho Kang, Hyosong Kim, Kumhee Yun, Hun Jung. AST-05X: A novel GCN2 inhibitor as a promising anti-cancer approach for sarcoma [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 1873.

N-Acetylcysteine Alleviates D-Galactose-Induced Injury of Ovarian Granulosa Cells in Female Rabbits by Regulating the PI3K/Akt/mTOR Signaling Pathway.

The ovary plays a crucial role in the reproductive system of female animals. Ovarian problems such as ovarian insufficiency, premature aging, polycystic ovary syndrome, and ovarian cysts may lead to ovulation disorders, abnormal hormone secretion, or luteal dysfunction, thereby increasing the risk of infertility and abortion. Only when the ovarian function and other organs in the reproductive system remain healthy and work normally can female animals be ensured to carry out reproductive activities regularly, improve the pregnancy rate and litter size, promote the healthy development of the fetus, and then improve their economic value. The follicle, as the functional unit of the ovary, is composed of theca cells, granulosa cells (GCs), and oocytes. GCs are the largest cell population and main functional unit in follicles and provide the necessary nutrients for the growth and development of follicles. N-acetylcysteine (NAC) is a prevalent and cell-permeable antioxidant molecule that effectively prevents apoptosis and promotes cellular survival. Over the past few years, its function in boosting reproductive performance in animals at the cellular level has been widely acknowledged. However, its specific role and mechanism in influencing GCs is yet to be fully understood. The objective of this study was to examine the effects of NAC on ovarian damage in female rabbits. For this purpose, D-galactose (D-gal) was first used to establish a model of damaged GCs, with exposure to 1.5 mg/mL of D-gal leading to substantial damage. Subsequently, varying concentrations of NAC were introduced to determine the precise mechanism through which it influences cell damage. Based on the results of the Cell Counting Kit-8 assay, flow cytometry, and Western blotting, it was found that 0.5 mg/mL of NAC could significantly suppress cell apoptosis and promote proliferation. In particular, it decreased the expression levels of Bax, p53, and Caspase-9 genes, while concurrently upregulating the expression of the BCL-2 gene. Moreover, NAC was found to alleviate intracellular oxidative stress, suppress the discharge of mitochondrial Cytochrome c, and boost the enzymatic activities of CAT (Catalase), GSH (Glutathione), and SOD (Superoxide dismutase). RNA sequencing analysis subsequently underscored the critical role of the PI3K/Akt/mTOR pathway in governing proliferation and apoptosis within GCs. These findings demonstrated that NAC could significantly influence gene expression within this pathway, thereby clarifying the exact relationship between the PI3K/Akt/mTOR signaling cascade and the underlying cellular processes controlling proliferation and apoptosis. In conclusion, NAC can reduce the expression of Bax, p53, and Caspase-9 genes, inhibit the apoptosis of GCs, improve cell viability, and resist D-gal-induced oxidative stress by increasing the activity of CAT, GSH, and SOD. The molecular mechanism of NAC in alleviating D-gal-induced ovarian GC injury in female rabbits by regulating the PI3K/Akt/mTOR signaling pathway provides experimental evidence for the effect of NAC on animal reproductive function at the cellular level.

Abstract 125: Development of humanized VEGFA models to assess preclinical efficacy of novel therapeutics in vivo

Abstract VEGFA is an essential growth factor required for angiogenesis in the context of normal wound healing as well as malignant tissue growth, ultimately facilitating the delivery of oxygen and nutrients to fuel cellular survival, expansion, and repair. VEGFA signaling has also been reported to exert effects on cancer cells and immune cells directly, with evidence suggesting that the pathway can both support tumor growth and inhibit immune surveillance. Thus, targeting VEGFA has been intensely explored as a therapeutic strategy for several cancer indications. Here, we generated a novel humanized VEGFA model (B-hVEGFA mice) to explore the ability of novel VEGFA-targeting therapeutics to curb cancer cell growth and angiogenesis in vivo. This was achieved by replacing the murine Vegfa gene with the corresponding human VEGFA coding region. We confirmed exclusive expression of human VEGF in lung homogenates of the humanized model at levels comparable to murine VEGF quantified in wild-type C57BL/6 mice. Immunohistochemical analysis at 8 weeks of age demonstrates no significant difference in the CD31+ area in several organs of the humanized mice when compared to wild-type C57BL/6 mice, including kidney, heart, liver, and eye. To assess the functional utility of this model in evaluating VEGFA modulators, tumor studies were conducted: murine colon cancer MC38 cells that were also engineered to express VEGFA in a similar manner (B-hVEGFA MC38 cells) were subcutaneously implanted into homozygous B-hVEGFA mice. Treatment with bevacizumab analog essentially abolished tumor growth in the humanized mice, while control tumors continued to expand over the 3 week study. To further evaluate the role of novel combination therapies or bispecific antibodies targeting VEGFA and PD-1, we also generated a triple humanized model expressing human VEGF, PD-1, and PD-L1 (B-hPD-1/hPD-L1/hVEGFA mice) by crossing B-hVEGFA mice with our B-hPD-1/hPD-L1 mice model, which expresses the extracellular domains of human PD-1 and PD-L1. Flow cytometric analysis of this model is currently underway to validate the model for further efficacy testing. Together, these humanized VEGF models provide robust in vivo platforms to evaluate novel VEGFA therapeutic candidates. Citation Format: Shujin Zhang, Chonghui Liu, Jin Guo, Zhiyuan Shen, James Jin, Bahetiyaer Huwatibieke, Yang Shen. Development of humanized VEGFA models to assess preclinical efficacy of novel therapeutics in vivo [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 125.

Abstract 2517: The amplification of TPX2 is a potential biomarker of oxaliplatin-sensitivity of colorectal cancers (CRCs) with CIN phenotype

Abstract The amplification of Chr20q11.21 harboring TPX2 gene is the most frequent copy number alteration among the cases of colorectal cancers (CRCs), especially left-sided ones. We retrospectively examined 2828 cases of CRC patients who took cancer-genome panel tests in Japan between June 2019 and November 2022. The time to first-line treatment failure was longer with regimen with oxaliplatin than with those with irinotecan in CRC patients with Chr20q11,21 amplification (12.2 versus 9.2 months, p=0.0481). Oxaliplatin induces double-strand breaks (DSBs) and then cellular apoptosis. A key event of the DNA damage response to DSBs for cellular survival is the extensive phosphorylation of Ser139 of Histone H2AX adjacent to the chromosomal break. TPX2 whose gene resides in Chr20q11,21 has been reported to repress the phosphorylation of H2AX upon ionizing radiation. The purpose of this study is to identify the relationship between the amplification of TPX2 and oxaliplatin sensitivity in human CRCs. The knockdown of TPX2 decreased the oxaliplatin-susceptibility of COLO320 and Caco-2, CIN phenotype CRC cell lines which highly expressed TPX2. However, TPX2 knockdown did not reduce the oxaliplatin sensitivity of HCT-116, an MSI phenotype CRC cell line with low-level of TPX2 expression. The knockdown of TPX2 in CIN phenotype CRC cells, not in the MSI phenotype CRC cells, enhanced the phosphorylation of H2AX upon the DNA-damage induced by oxaliplatin. These findings suggest that amplification of TPX2 contributes to the oxaliplatin-susceptibility of CRCs with CIN phenotype through DNA repair machinery. Citation Format: Shohei Ueno, Taichi Isobe, Ryosuke Taguchi, Kenji Tsuchihashi, Koichi Akashi, Eishi Baba. The amplification of TPX2 is a potential biomarker of oxaliplatin-sensitivity of colorectal cancers (CRCs) with CIN phenotype [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 2517.

Abstract 5262: MBO enhances anti-tumor immunity in pancreatic ductal adenocarcinoma by inducing immunogenic apoptosis

Abstract Pancreatic ductal adenocarcinoma (PDAC) poses significant therapeutic challenges due to its aggressive nature and limited treatment options. In this study, we explored the anti-cancer potential of MBO, a compound selected through drug repurposing strategy based on its cytotoxic ability and modulation of key survival pathways in PDAC. Our preliminary in vitro experiments demonstrated MBO's potent cytotoxicity against various PDAC cell lines, inhibiting cellular growth and clonogenicity. MBO induced G1 phase cell cycle arrest in a concentration-dependent manner. In the next step, in vivo, studies using xenograft and orthotopic mouse models confirmed MBO's ability to suppress tumor growth and increase CD8+ T cell infiltration. MBO demonstrated a favorable tumor suppressive activity wherein it suppressed tumor growth by approximately 49% and 56% in xenograft and orthotopic models, respectively. A CD8+ T cell depletion experiment revealed partial dependence on CD8+ T cells for MBO's overall anti-tumor efficacy. Further, combining MBO with anti-PD1 therapy exhibited a synergistic effect, enhancing overall T cell infiltration, particularly CD8+ T cells. Our mechanistic studies revealed that MBO induced immunogenic apoptosis, as evidenced by increased expression of immunogenic cell death markers (HSP90 and calreticulin) and apoptotic markers. To further delineate the mechanism, we performed RPPA profiling. RPPA analysis indicated MBO's impact on mitochondrial gene expression and stress response pathways, suggesting its involvement in disrupting cellular survival mechanisms along with stress-induced immunogenic marker expression. Overall, this study demonstrates MBO as a promising anti-cancer agent with the potential to serve as an immune adjuvant. Particularly, in combination with immunotherapies, MBO can serve as a potential option to improve immunotherapeutic response in PDAC tumors providing valuable insights for developing novel therapeutic strategies in PDAC. Citation Format: Shreyas Ramchandra Gaikwad, Sanjay K. Srivastava. MBO enhances anti-tumor immunity in pancreatic ductal adenocarcinoma by inducing immunogenic apoptosis [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 5262.

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 &amp; 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.

Clinical Insights into Structure, Regulation, and Targeting of ABL Kinases in Human Leukemia.

Chronic myeloid leukemia is a multistep, multi-lineage myeloproliferative disease that originates from a translocation event between chromosome 9 and chromosome 22 within the hematopoietic stem cell compartment. The resultant fusion protein BCR::ABL1 is a constitutively active tyrosine kinase that can phosphorylate multiple downstream signaling molecules to promote cellular survival and inhibit apoptosis. Currently, tyrosine kinase inhibitors (TKIs), which impair ABL1 kinase activity by preventing ATP entry, are widely used as a successful therapeutic in CML treatment. However, disease relapses and the emergence of resistant clones have become a critical issue for CML therapeutics. Two main reasons behind the persisting obstacles to treatment are the acquired mutations in the ABL1 kinase domain and the presence of quiescent CML leukemia stem cells (LSCs) in the bone marrow, both of which can confer resistance to TKI therapy. In this article, we systemically review the structural and molecular properties of the critical domains of BCR::ABL1 and how understanding the essential role of BCR::ABL1 kinase activity has provided a solid foundation for the successful development of molecularly targeted therapy in CML. Comparison of responses and resistance to multiple BCR::ABL1 TKIs in clinical studies and current combination treatment strategies are also extensively discussed in this article.

Surface-Engineered Titanium with Nanoceria to Enhance Soft Tissue Integration Via Reactive Oxygen Species Modulation and Nanotopographical Sensing.

The design of implantable biomaterials involves precise tuning of surface features because the early cellular fate on such engineered surfaces is highly influenced by many physicochemical factors [roughness, hydrophilicity, reactive oxygen species (ROS) responsiveness, etc.]. Herein, to enhance soft tissue integration for successful implantation, Ti substrates decorated with uniform layers of nanoceria (Ce), called Ti@Ce, were optimally developed by a simple and cost-effective in situ immersion coating technique. The characterization of Ti@Ce shows a uniform Ce distribution with enhanced roughness (∼3-fold increase) and hydrophilicity (∼4-fold increase) and adopted ROS-scavenging capacity by nanoceria coating. When human gingival fibroblasts were seeded on Ti@Ce under oxidative stress conditions, Ti@Ce supported cellular adhesion, spreading, and survivability by its cellular ROS-scavenging capacity. Mechanistically, the unique nanocoating resulted in higher expression of amphiphysin (a nanotopology sensor), paxillin (a focal adhesion protein), and cell adhesive proteins (collagen-1 and fibronectin). Ti@Ce also led to global chromatin condensation by decreasing histone 3 acetylation as an early differentiation feature. Transcriptome analysis by RNA sequencing confirmed the chromatin remodeling, antiapoptosis, antioxidant, cell adhesion, and TGF-β signaling-related gene signatures in Ti@Ce. As key fibroblast transcription (co)factors, Ti@Ce promotes serum response factor and MRTF-α nucleus localization. Considering all of this, it is proposed that the surface engineering approach using Ce could improve the biological properties of Ti implants, supporting their functioning at soft tissue interfaces and utilization as a bioactive implant for clinical conditions such as peri-implantitis.

The Multiple Roles of Heat Shock Proteins in the Development of Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD), a chronic inflammatory condition of the human intestine, comprises Crohn's Disease (CD) and Ulcerative Colitis (UC). IBD causes severe gastrointestinal symptoms and increases the risk of developing colorectal carcinoma. Although the etiology of IBD remains ambiguous, complex interactions between genetic predisposition, microbiota, epithelial barrier, and immune factors have been implicated. The disruption of intestinal homeostasis is a cardinal characteristic of IBD. Patients with IBD exhibit intestinal microbiota dysbiosis, impaired epithelial tight junctions, and immune dysregulation; however, the relationship between them is not completely understood. As the largest body surface is exposed to the external environment, the gastrointestinal tract epithelium is continuously subjected to environmental and endogenous stressors that can disrupt cellular homeostasis and survival. Heat shock proteins (HSPs) are endogenous factors that play crucial roles in various physiological processes, such as maintaining intestinal homeostasis and influencing IBD progression. Specifically, HSPs share an intricate association with microbes, intestinal epithelium, and the immune system. In this review, we aim to elucidate the impact of HSPs on IBD development by examining their involvement in the interactions between the intestinal microbiota, epithelial barrier, and immune system. The recent clinical and animal models and cellular research delineating the relationship between HSPs and IBD are summarized. Additionally, new perspectives on IBD treatment approaches have been proposed.

Recent advances in mitochondria-targeting theranostic agents.

For its vital role in maintaining cellular activity and survival, mitochondrion is highly involved in various diseases, and several strategies to target mitochondria have been developed for specific imaging and treatment. Among these approaches, theranostic may realize both diagnosis and therapy with one integrated material, benefiting the simplification of treatment process and candidate drug evaluation. A variety of mitochondria-targeting theranostic agents have been designed based on the differential structure and composition of mitochondria, which enable more precise localization within cellular mitochondria at disease sites, facilitating the unveiling of pathological information while concurrently performing therapeutic interventions. Here, progress of mitochondria-targeting theranostic materials reported in recent years along with background information on mitochondria-targeting and therapy have been briefly summarized, determining to deliver updated status and design ideas in this field to readers.

Abstract B093: Investigating early events of ovarian cancer transcoelomic metastasis identifies the small Rho-GTPase RHOV as an essential gene for cellular detachment and aggregate formation

Abstract B093: Investigating early events of ovarian cancer transcoelomic metastasis identifies the small Rho-GTPase RHOV as an essential gene for cellular detachment and aggregate formation