Increased Tumor Cell Research Articles

PX-478 induces apoptosis in acute myeloid leukemia under hypoxia by inhibiting the PI3K/AKT/mTOR pathway through downregulation of GBE1

Acute myeloid leukemia (AML) is a highly heterogeneous hematologic malignancy characterized by limited therapeutic options and a pronounced tendency for relapse. PX-478, a novel inhibitor of hypoxia-inducible factor 1-alpha (HIF-1α), has demonstrated antitumor activity across various cancer models, but its specific role in AML remains unexplored. This study aimed to explore the potential target and mechanism of PX-478-induced AML cell apoptosis. First, PX-478 induced AML cell apoptosis in vitro under hypoxia via modulation of the Bcl-2 family and activation of the mitochondria-mediated caspase cascade, exhibiting a concentration-dependent effect. Additionally, in vivo administration of PX-478 led to notable inhibition of subcutaneous AML xenograft growth in mice, coupled with increased tumor cell apoptosis. RNA sequencing and cellular studies revealed downregulation of the PI3K/AKT/mTOR signaling pathway in PX-478-treated cells. Consistently, cellular studies also implicated PI3K/AKT/mTOR pathway in PX-478-induced AML cell apoptosis. Furthermore, by screening for RNA sequencing differential genes and subsequent experimental verification, Glycogen branching enzyme 1 (GBE1) may be involved in PX-478-induced apoptosis in AML cells. We found that inhibiting GBE1 expression in AML cells (siGBE1) led to downregulation of the PI3K/AKT/mTOR pathway and induced apoptosis. In experiments using AML cells with reduced GBE1 expression (shGBE1), PX-478 treatment did not further downregulate the pathway or enhance apoptosis. Re-expression of GBE1 in shGBE1 cells alleviated apoptosis and reduced PX-478- induced apoptosis and pathway downregulation. In conclusion, our findings provide convincing evidence that PX-478 induces apoptosis by inhibiting the PI3K/AKT/mTOR pathway through downregulation of GBE1 in AML cells

Uncovering the protective role of lipid droplet accumulation against acid-induced oxidative stress and cell death in osteosarcoma

Extracellular acidosis stemming from altered tumor metabolism promotes cancer progression by enabling tumor cell adaptation to the hostile microenvironment. In osteosarcoma, we have previously shown that acidosis increases tumor cell survival alongside substantial lipid droplet accumulation. In this study, we explored the role of lipid droplet formation in mitigating cellular stress induced by extracellular acidosis in osteosarcoma cells, thereby enhancing tumor survival during progression. Specifically, we examined how lipid droplets shield against reactive oxygen species induced by extracellular acidosis. We demonstrated that lipid droplet biogenesis is critical for acid-exposed tumor cell survival, as it starts shortly after acid exposure (24 h) and inversely correlates with ROS levels (DCFH-DA assay), lipid peroxidation (Bodipy assay), and the antioxidant response, as also revealed by NRF2 transcript. Additionally, extracellular metabolites, such as lactate, and interaction with mesenchymal stromal cells within the tumor microenvironment intensify lipid droplet build-up in osteosarcoma cells. Critically, upon targeting two key proteins implicated in LD formation - PLIN2 and DGAT1 - cell viability significantly declined while ROS production escalated. In summary, our findings underscore the vital reliance of acid-exposed tumor cells on lipid droplet formation to scavenge oxidative stress. We conclude that the rewiring of lipid metabolism driven by microenvironmental cues is of paramount importance for the survival of metabolically altered osteosarcoma cells in acidic condition. Overall, we suggest that targeting key members of lipid droplet biogenesis may eradicate more aggressive and resistant tumor cells, uncovering potential new treatment strategies for osteosarcoma.

Lactate reprograms glioblastoma immunity through CBX3-regulated histone lactylation.

Glioblastoma (GBM), an aggressive brain malignancy with a cellular hierarchy dominated by GBM stem cells (GSCs), evades antitumor immunity through mechanisms that remain incompletely understood. Like most cancers, GBMs undergo metabolic reprogramming toward glycolysis to generate lactate. Here, we show that lactate production by patient-derived GSCs and microglia/macrophages induces tumor cell epigenetic reprogramming through histone lactylation, an activating modification that leads to immunosuppressive transcriptional programs and suppression of phagocytosis via transcriptional upregulation of CD47, a "don't eat me" signal, in GBM cells. Leveraging these findings, pharmacologic targeting of lactate production augments efficacy of anti-CD47 therapy. Mechanistically, lactylated histone interacts with the heterochromatin component chromobox protein homolog 3 (CBX3). Although CBX3 does not possess direct lactyltransferase activity, CBX3 binds histone acetyltransferase (HAT) EP300 to induce increased EP300 substrate specificity toward lactyl-CoA and a transcriptional shift toward an immunosuppressive cytokine profile. Targeting CBX3 inhibits tumor growth by both tumor cell-intrinsic mechanisms and increased tumor cell phagocytosis. Collectively, these results suggest that lactate mediates metabolism-induced epigenetic reprogramming in GBM that contributes to CD47-dependent immune evasion, which can be leveraged to augment efficacy of immuno-oncology therapies.

Actin Dysregulation Induces Neuroendocrine Plasticity and Immune Evasion: A Vulnerability of Small Cell Lung Cancer.

Small cell lung cancer (SCLC) is aggressive with limited therapeutic options. Despite recent advances in targeted therapies and immunotherapies, therapy resistance is a recurring issue, which might be partly due to tumor cell plasticity, a change in cell fate. Nonetheless, the mechanisms underlying tumor cell plasticity and immune evasion in SCLC remain elusive. CRACD, a capping protein inhibitor that promotes actin polymerization, is frequently inactivated in SCLC. Cracd knockout (KO) transforms preneoplastic cells into SCLC tumor-like cells and promotes in vivo SCLC development driven by Rb1, Trp53, and Rbl2 triple KO. Cracd KO induces neuroendocrine (NE) plasticity and increases tumor cell heterogeneity of SCLC tumor cells via dysregulated NOTCH1 signaling by actin cytoskeleton disruption. CRACD depletion also reduces nuclear actin and induces EZH2-mediated H3K27 methylation. This nuclear event suppresses the MHC-I genes and thereby depletes intratumoral CD8+ T cells for accelerated SCLC tumorigenesis. Pharmacological blockade of EZH2 inhibits CRACD-negative SCLC tumorigenesis by restoring MHC-I expression and immune surveillance. Unsupervised single-cell transcriptomics identifies SCLC patient tumors with concomitant inactivation of CRACD and downregulated MHC-I pathway. This study defines CRACD, an actin regulator, as a tumor suppressor that limits cell plasticity and immune evasion and proposes EZH2 blockade as a viable therapeutic option for CRACD-negative SCLC.

TMIC-58. LEVERAGING VIRO-IMMUNOTHERAPY BY TARGETING IGF2-IGF1R SIGNALING

Abstract While an FDA-approved oncolytic herpes simplex-1 virus (oHSV) has shown therapeutic promise with superior safety, accumulating clinical data revealed that its therapeutic efficacy is observed in a small subset of patients. Here, we show that NFκB-mediated Insulin-like Growth Factor 2 (IGF2)/Insulin-like Growth Factor-1 Receptor (IGF1R) signaling pathway as a key modulator for oHSV therapy-mediated tumor resistance. RNA sequencing on the oHSV-infected primary glioblastoma (GBM) and breast cancer (BC) cells identified IGF2 as one of the top 10 upregulated secretomes. Transcriptomic analysis also revealed significant upregulation/enrichment of genes related to IGF2-IGF1R-MAPK pathway in oHSV-treated tumor cells. Infection with oHSV in GBM and BC cells up-regulated IGF2 transcription via direct binding of NFκB in the IGF2 promoter 3. Compromising the IGF2-IGF1R signaling pathway using IGF2 neutralizing antibody significantly increased oHSV-mediated tumor cell killing in vitro and mice survival in vivo. To circumvent this and promptly translate our findings in clinical settings, we have developed a novel oHSV, oHSV-D11mt, by incorporating modified IGF2R domain 11 into the parental oHSV genome to function as IGF2 decoy receptor as a single-agent modality. oHSV-D11mt specifically bind to IGF2 not IGF1, blocks oHSV-induced IGF2-IGF1R signaling, increases tumor cell killing, decreases oHSV-induced neutrophils/PMN-MDSCs infiltration, immune suppressive/proangiogenic cytokine secretion, and increases CD8+ cytotoxic T lymphocytes (CTLs) activation, resulting in increased virus propagation and mice survival. These findings suggest that IGF2-IGF1R signaling is a novel target to overcome oHSV therapy resistance and oHSV-D11mt could be used for improved viro-immunotherapy.

EXTH-69. DEVELOPMENT OF A NOVEL, HUMAN ANTIBODY TO IMPROVE ONCOLYTIC VIRUS THERAPY FOR GLIOBLASTOMA

Abstract Glioblastoma (GBM) is the most aggressive, malignant, primary brain tumor with abysmal overall survival. GBM is regarded as an “immune cold” tumor due to poor immune cell infiltration and immunosuppressive signaling in the tumor microenvironment (TME). Oncolytic herpes virus (oHSV) therapy has emerged as a possible therapeutic avenue for solid tumors such as GBM. We have observed that oHSV-treated tumor cells release extracellular ATP (eATP) which functions as immunostimulatory signaling molecule. In the TME, eATP is rapidly hydrolyzed into immunosuppressive adenosine by ectoenzymes CD39 and CD73. Using global CD73 knock out (CD73KO) mice or a function-blocking murine antibody, we found that blocking CD73 activity improves oHSV therapy in vivo. Intracranial tumor-bearing CD73KO mice respond significantly better to oHSV therapy than wild type (WT). These long-term survivors also rejected a subsequent tumor challenge, demonstrating development of a memory response. scRNA-seq revealed significantly increased immune cell infiltration in CD73KO mice compared to WT. We evaluated cellular crosstalk using CellChat and uncovered a major CCL-directed signaling pathway in the CD73KO mice. Furthermore, we identified a novel, human CD73 antibody from panning an scFv phage display library derived from human tonsils. This antibody, Ab6, demonstrated functional inhibition of purified CD73 and very high binding affinity for CD73. Co-culture of human GBM cells treated with OV and Ab6 and donor PBMCs resulted in increased tumor cell death. Additionally, human DCs exposed to Ab6 and OV-treated conditioned media were better able to activate T cells. To evaluate in vivo efficacy of this novel antibody, we have generated custom humanized CD73 knock-in mice wherein human CD73 has replaced murine CD73. We are currently evaluating the efficacy of Ab6 and oHSV in these mice against intracranial glioma. These results will support the translation of Ab6 as a potential immune therapeutic to add to the arsenal against brain tumors.

DDDR-37. OHSV AND RADIATION THERAPIES SENSITIZE GLIOBLASTOMA TO IGF1R-TARGETED THERAPY AND SYNERGIZE IN TRIPLE COMBINATION THERAPY

Abstract Glioblastoma (GBM) continues to have a dismal prognosis despite remarkable advances in the field due to both tumor-intrinsic factors (i.e., IDH1 or EGFRvIII mutations) and extrinsic factors (i.e., relating to the tumor microenvironment (TME)), necessitating therapeutic innovation. Oncolytic herpes simplex virus-1 (oHSV) is an FDA-approved therapy that has shown promising results in clinical trials; however, therapeutic efficacy is limited to a small subset of patients. Thus, elucidating both the tumor-TME interplay and feedback/feedforward tumor-cell signaling in the context of viro-immunotherapy is essential in augmenting therapeutic outcomes. We recently discovered a novel mechanism of resistance to oHSVs, in which infection increases secretion of Insulin-like growth factor 2 (IGF2), activating the Insulin-like Growth Factor-1 Receptor (IGF1R). Upregulation of the IGF1R signaling pathway in GBM is correlated with poor prognosis and has been implicated in resistance to conventional therapies including radiotherapy (RTx). Herein, we further elucidate the impact of oHSVs on IGF1R activation, demonstrating a dose-dependent enhancement of downstream signaling. While IGF1R targeting therapies (e.g., OSI-966, Picropodophyllin (PPP)) have displayed limited efficacy in clinical trials, they significantly increased oHSV-induced cytotoxicity in all tested primary GBM cells compared to either agent alone in vitro and in vivo, resulting in a dose-dependent increase in PARP and caspase 3 activity by western blot and immunohistochemistry. We further found that RTx-induced IGF1 secretion and subsequent IGF1R activation were enhanced when combined with oHSV treatment. Triple combination therapy with oHSV, IGF1R inhibition, and RTx significantly increased tumor cell killing in vitro and improved survival of orthotopic GBM tumor-bearing mice. Collectively, our study provides preclinical evidence of enhanced therapeutic efficacy of oHSVs and RTx in combination with IGF1R blockade, supporting future use of IGF1R inhibitors in combination with the standard of care and FDA-approved oHSV therapies in patients with GBM.

Hsa_circ_0109320 Serves as a Novel Circular RNA Biomarker in Non-small Cell Lung Cancer by Promoting Metastasis.

Non-small cell lung cancer (NSCLC), including squamous cell carcinoma and adenocarcinoma, ranks among the top 10 cancers worldwide in terms of prevalence and mortality. NSCLC, a highly malignant tumor, exhibits distant invasion and migration as well as an unfavorable prognosis. As an innovative circular RNA, hsa _circ_0109320 (circ_0109320) has been recognized as a promising cancer modulator. However, our understanding of the influence of circ_0109320 in NSCLC remains insufficient. Our research explored the clinical significance and effects of circ_0109320 on oncogenic non-small cell lung cancer (NSCLC) phenotypes. Microarray analysis and qPCR indicated that circ_0109320 expression in NSCLC specimens increased relative to that in adjacent normal tissues and was further elevated in metastatic lymph nodes. The specimens acquired from 25 patients confirmed these findings. Additionally, circ_0109320 indicated a good score (AUC = 0.688, P = 0.013) on the ROC curves, which suggests its suitability as a promising biomarker for lung cancer. Meanwhile, circ_0109320 was noticeably upregulated in lung cancer (LC) cell lines compared to human bronchial epithelial cells. Next, we performed loss- and gain-of-function experiments to examine the role of circ_0109320 in the tumor phenotypes of the cell lines. We observed that depletion or overexpression of circ_0109320 did not alter cell viability. However, the ectopic removal of circ_0109320 repressed the migration and invasion of A549 and SK-MES-1 cells, whereas circ_0109320 overexpression promoted cell migration and invasion. Furthermore, the examination of epithelial-mesenchymal transition (EMT) markers indicated that circ_0109320 elevates cell EMT activity. In conclusion, circ_0109320 level was highly associated with increased tumor cell proliferation and metastasis. circ_0109320 could be a promising predictor of clinical outcomes and a reliable target to treat NSCLC by inhibiting metastasis.

Liposomes-mediated enhanced antitumor effect of docetaxel with BRD4-PROTAC as synergist for breast cancer chemotherapy/immunotherapy.

It has been reported that proteolysis-targeting chimeras (PROTACs) can effectively degrade intracellular oncogenic proteins, providing an ideal strategy for cancer treatment. ARV825, a bromodomain-containing protein 4 (BRD4)-PROTAC, has demonstrated the capacity to enhance the antitumor effect of the classic chemotherapeutic agent docetaxel (DTX). However, there are three major challenges to the broader in vivo application of ARV825: poor solubility, poor permeability, and off-target effects. Additionally, the efficient co-delivery of ARV825 and DTX to tumor tissues for a synergistic therapeutic effect remains unresolved. In this study, liposomes were utilized as co-delivery vehicles for ARV825 and DTX to effectively address these issues. The well-established liposomes significantly improved the solubility of both ARV825 and DTX while maintaining a sustained release profile in blood-mimetic conditions. The co-loaded liposomes accumulated in tumor tissues via the enhanced permeability and retention (EPR) effect. After internalization, ARV825 effectively degraded intracellular BRD4 proteins and downregulated the expression of both Bcl-2 and PD-L1 proteins, thereby increasing tumor cell apoptosis and enhancing the tumor immune response. This, in turn, augmented the antitumor effect of DTX in vivo without undesired side effects. In conclusion, BRD4-PROTAC may serve as a promising synergistic agent alongside the conventional chemotherapeutic agent DTX, with liposomes functioning as effective co-delivery vehicles.

TGF-β Signaling Loop in Pancreatic Ductal Adenocarcinoma Activates Fibroblasts and Increases Tumor Cell Aggressiveness.

The interaction between cancer cells and cancer-associated fibroblasts (CAFs) is a key determinant of the rapid progression, high invasiveness, and chemoresistance of aggressive desmoplastic cancers such as pancreatic ductal adenocarcinoma (PDAC). Tumor cells are known to reprogram fibroblasts into CAFs by secreting transforming growth factor beta (TGF-β), amongst other cytokines. In turn, CAFs produce soluble factors that promote tumor-cell invasiveness and chemoresistance, including TGF-β itself, which has a major role in myofibroblastic CAFs. Such a high level of complexity has hampered progress toward a clear view of the TGFβ signaling loop between stromal fibroblasts and PDAC cells. Here, we tackled this issue by using co-culture settings that allow paracrine signaling alone (transwell systems) or paracrine and contact-mediated signaling (3D spheroids). We found that TGF-β is critically involved in the activation of normal human fibroblasts into alpha-smooth muscle actin (α-SMA)-positive CAFs. The TGF-β released by CAFs accounted for the enhanced proliferation and resistance to gemcitabine of PDAC cells. This was accompanied by a partial epithelial-to-mesenchymal transition in PDAC cells, with no increase in their migratory abilities. Nevertheless, 3D heterospheroids comprising PDAC cells and fibroblasts allowed monitoring the pro-invasive effects of CAFs on cancer cells, possibly due to combined paracrine and physical contact-mediated signals. We conclude that TGF-β is only one of the players that mediates the communication between PDAC cells and fibroblasts and controls the acquisition of aggressive phenotypes. Hence, these advanced in vitro models may be exploited to further investigate these events and to design innovative anti-PDAC therapies.

The Biological Roles of ZKSCAN3 (ZNF306) in the Hallmarks of Cancer: From Mechanisms to Therapeutics.

ZKSCAN3 (also known as ZNF306) plays a pivotal role in the regulation of various cellular processes that are fundamental to the development of cancer. It has been widely acknowledged as a key contributor to cancer progression, with its overexpression consistently reported in a broad spectrum of malignancies. Importantly, clinical studies have demonstrated a significant association between elevated ZKSCAN3 levels and adverse prognosis, as well as resistance to therapeutic drugs. Specifically, ZKSCAN3 promotes tumor progression by enhancing multiple hallmark features of cancer and promoting the acquisition of cancer-specific phenotypes. These effects manifest as increased tumor cell proliferation, invasion, and metastasis, accompanied by inhibiting tumor cell apoptosis and modulating autophagy. Consequently, ZKSCAN3 emerges as a promising prognostic marker, and targeting its inhibition represents a potential strategy for anti-tumor therapy. In this review, we provide an updated perspective on the role of ZKSCAN3 in governing tumor characteristics and the underlying molecular mechanisms. Furthermore, we underscore the clinical relevance of ZKSCAN3 and its potential implications for tumor prognosis and therapeutic strategies.

Enhanced Antitumor Efficacy of Oncolytic Vaccinia Virus Therapy Through Keratin-Mediated Delivery in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) represents an aggressive subtype characterized by high rates of recurrence and metastasis, necessitating the exploration of alternative treatment strategies. Oncolytic vaccinia virus (OVV) therapy has emerged as a promising approach, selectively infecting and destroying tumor cells. However, its efficacy is often hampered by inadequate viral distribution within the tumor microenvironment. Here, we investigate the potential of keratin (KTN) as a carrier for OVV delivery to enhance viral distribution and antitumor efficacy. In vitro assays revealed that KTN significantly improves OVV stability, leading to increased tumor cell apoptosis and necrosis. Furthermore, KTN effectively inhibits cancer cell migration by suppressing the epithelial-mesenchymal transition (EMT) process and downregulating metastasis-related proteins. These findings are corroborated in a syngeneic TNBC mouse model, where KTN-mediated OVV delivery enhances cytotoxic T cell-mediated antitumor immune responses without compromising the anti-angiogenic effects of the virus. Notably, KTN alone exhibits antitumor effects by suppressing tumor growth and metastasis, underscoring its potential as a standalone therapeutic agent. In conclusion, our study underscores the promise of KTN-mediated OVV delivery as a promising therapeutic strategy for TNBC. By improving viral distribution, suppressing EMT, and enhancing antitumor immunity, this approach holds significant potential for enhancing patient outcomes in TNBC treatment. Further investigation is warranted to explore the broader utility of KTN in various cancer therapy approaches.

Cell Populations in Human Breast Cancers are Molecularly and Biologically Distinct with Age.

Aging is associated with increased breast cancer risk and outcomes are worse for the oldest and youngest patients, regardless of subtype. It is not known how cells in the breast tumor microenvironment are impacted by age and how they might contribute to age-related disease pathology. Here, we discover age-associated differences in cell states and interactions in human estrogen receptor-positive (ER+) and triple-negative breast cancers (TNBC) using new computational analyses of existing single-cell gene expression data. Age-specific program enrichment (ASPEN) analysis reveals age-related changes, including increased tumor cell epithelial-mesenchymal transition, cancer-associated fibroblast inflammatory responses, and T cell stress responses and apoptosis in TNBC. ER+ breast cancer is dominated by increased cancer cell estrogen receptor 1 (ESR1) and luminal cell activity, reduced immune cell metabolism, and decreased vascular and extracellular matrix (ECM) remodeling with age. Cell interactome analysis reveals candidate signaling pathways that drive many of these cell states. This work lays a foundation for discovery of age-adapted therapeutic interventions for breast cancer.

Is Immunohistochemical Galectin-3 Expression Associated with the Epithelial-Mesenchymal Transition in High- and Low-Grade Invasive Urothelial Carcinomas of the Bladder?

Background/Objectives: Bladder cancer, predominantly urothelial carcinoma, is an important malignancy of the urinary system. Despite the same histologic grade and stage, some patients seem to have a worse prognosis. In this context, the epithelial-mesenchymal transition (EMT), characterized by the loss of E-cadherin and gain of vimentin expression, is an important process in tumor progression. Galectin-3, a lactose-binding protein involved in various cellular processes, has been associated with increased tumor cell migration, invasion, and treatment resistance. Methods: In this study, 223 bladder cancer cases were examined, and E-cadherin, vimentin, and galectin-3 expression was evaluated by immunohistochemical staining in tumor budding areas and invasive components. These markers were also correlated with clinicopathological parameters, including tumor grade and stage. Results: The results indicated a significant decrease in E-cadherin expression and an increase in vimentin staining in higher-grade and higher-stage tumors, supporting EMT involvement. Galectin-3 expression was notably higher in T1 high-grade tumors but decreased in T2 stage tumors. Despite this, no significant correlation was found between galectin-3 and E-cadherin or vimentin, suggesting a complex role of galectin-3 in EMT. Conclusions: High galectin-3 expression in T1 high-grade tumors highlights its potential role in early tumor progression and as a therapeutic target. However, the decrease in its expression in advanced stages underscores the need for further research to understand its multifaceted involvement in bladder cancer. These findings suggest that while galectin-3 may contribute to the EMT and early tumor progression, its exact role and potential as a therapeutic target require more detailed investigation.

Reprogramming the Tumor Immune Microenvironment Through Activatable Photothermal Therapy and GSH depletion Using Liposomal Gold Nanocages to Potentiate Anti-Metastatic Immunotherapy.

Cancer immunotherapy offers significant clinical benefits for patients with advanced or metastatic tumors. However, immunotherapeutic efficacy is often hindered by the tumor microenvironment's high redox levels, leading to variable patient outcomes. Herein, a therapeutic liposomal gold nanocage (MGL) is innovatively developed based on photo-triggered hyperthermia and a releasable strategy by combining a glutathione (GSH) depletion to remodel the tumor immune microenvironment, fostering a more robust anti-tumor immune response. MGL comprises a thermosensitive liposome shell and a gold nanocage core loaded with maleimide. The flexible shell promotes efficient uptake by cancer cells, enabling targeted destruction through photothermal therapy while triggering immunogenic cell death and the maturation of antigen-presenting cells. The photoactivated release of maleimide depletes intracellular GSH, increasing tumor cell sensitivity to oxidative stress and thermal damage. Conversely, GSH reduction also diminishes immunosuppressive cell activity, enhances antigen presentation, and activates T cells. Moreover, photothermal immunotherapy decreases elevated levels of heat shock proteins in tumor cells, further increasing their sensitivity to hyperthermia. In summary, MGL elicited a robust systemic antitumor immune response through GSH depletion, facilitating an effective photothermal immunotherapeutic strategy that reprograms the tumor microenvironment and significantly inhibits primary and metastatic tumors. This approach demonstrates considerable translational potential and clinical applicability.

Exploring Autophagy in Cancer: Therapeutic Perspectives

Autophagy is a catabolic mechanism crucial for sustaining cellular homeostasis, and in this process, encapsulated degraded inside repurposed to facilitate metabolic processes. In cancer, autophagy has a dual role: it acts as a tumor suppressor by preventing the buildup of damaged cellular components, but also as a survival mechanism, that supports tumor growth under stress. Cancer cells often trigger autophagy to manage the increased metabolic demands of rapid growth. This stress tolerance allows tumor cells to maintain energy production, contributing to both tumor progression and resistance to treatment. Preclinical studies have shown that autophagy inhibition reinstates chemotherapeutic sensitivity and increases tumor cell mortality. These findings indicate that targeting autophagy may represent a viable therapeutic approach, with early-phase clinical trials exploring the use of hydroxychloroquine alongside chemotherapy or targeted treatments. As comprehension of autophagy in oncology advances, there is an increasing interest in creating more targeted and efficacious autophagy inhibitors for therapeutic applications.

Nimodipine Used with Vincristine: Protects Schwann Cells and Neuronal Cells from Vincristine-Induced Cell Death but Increases Tumor Cell Susceptibility.

The chemotherapeutic agent vincristine is commonly used for a variety of hematologic cancers, as well as solid tumors of the head and neck, bronchial carcinoma, as part of the procarbazine, lomustine and vincristine (PCV) regimen, for glioma. Damage to nerve tissue (neuropathy) is often dose-limiting and restricts treatment. Nimodipine is a calcium antagonist that has also shown neuroprotective properties in preliminary studies. In this approach here, we investigated the effects of the combination of vincristine and nimodipine on three cancer cell lines (A549, SAS and LN229) and neuronal cells (RN33B, SW10). Fluorescence microscopy, lactate dehydrogenase (LDH) assays and Western blot analyses were used. Nimodipine was able to enhance the cell death effects of vincristine in all tumor cells, while neuronal cells were protected and showed less cell death. There was an opposite change in the protein levels of Ak strain transforming/protein kinase B (AKT) in tumor cells (down) and neuronal cells (up), with simultaneous increased protein levels of cyclic adenosine monophosphate response element-binding protein (CREB) in all cell lines. In the future, this approach may improve tumor response to chemotherapy and reduce unwanted side effects such as neuropathy.

Intracellular zinc protects tumours from T cell-mediated cytotoxicity

Tumour immune evasion presents a significant challenge to the effectiveness of cancer immunotherapies. Recent advances in high-throughput screening techniques have uncovered that loss of antigen presentation and cytokine signalling pathways are central mechanisms by which tumours evade T cell immunity. To uncover additional vulnerabilities in tumour cells beyond the well-recognized antigen presentation pathway, we conducted a genome-wide CRISPR/Cas9 screen to identify genes that mediate resistance to chimeric-antigen receptor (CAR)-T cells, which function independently of classical antigen presentation. Our study revealed that loss of core-binding factor subunit beta (CBFβ) enhances tumour cell resistance to T cell killing, mediated through T cell-derived TNF. Mechanistically, RNA-sequencing and elemental analyses revealed that deletion of CBFβ disrupts numerous pathways including those involved in zinc homoeostasis. Moreover, we demonstrated that modulation of cellular zinc, achieved by supplementation or chelation, significantly altered tumour cell susceptibility to TNF by regulating the levels of inhibitor of apoptosis proteins. Consistent with this, treatment of tumour cells with a membrane-permeable zinc chelator had no impact on tumour cell viability alone, but significantly increased tumour cell lysis by CD8+ T cells in a TNF-dependent but perforin-independent manner. These results underscore the crucial role of intracellular zinc in regulating tumour cell susceptibility to T cell-mediated killing, revealing a novel vulnerability in tumour cells that might be exploited for the development of future cancer immunotherapeutics.

CD98hc promotes drug resistance in extranodal natural killer/T cell lymphoma through tumor cell-derived small extracellular vesicles.

Extranodal natural killer/T cell lymphoma (ENKTL) shows a high rate of recurrence after chemoradiotherapy. Drug resistance can be mediated by the cargo of small extracellular vesicles (sEVs). Here, we show that high abundance of the transmembrane glycoprotein CD98hc in tumor cells and serum sEVs was associated with ENKTL progression and drug resistance. Mechanistically, PEGylated-asparaginase (PEG-asp) treatment, a common therapy against ENKTL, promoted the translocation of the transcription factor ATF4 to the nucleus, where it was stabilized by USP1 and subsequently increased CD98hc expression. CD98hc delivered in tumor cell-derived sEVs increased tumor cell proliferation and drug resistance in a cultured human NK lymphoma cell line, animal models, and samples from patients with refractory/relapse ENKTL. Moreover, inhibiting both USP1 and EV secretion synergistically enhanced the cytotoxicity of PEG-asp. These data suggest that targeting CD98hc in the treatment of ENKTL may be beneficial in overcoming drug resistance.

Low ozone concentrations do not exert cytoprotective effects on tamoxifen-treated breast cancer cells in vitro.

Medical treatment with low ozone concentrations proved to exert therapeutic effects in various diseases by inducing a cytoprotective antioxidant response through the nuclear factor erythroid derived-like 2 (Nrf2) transcription factor pathway. Low ozone doses are increasingly administered to oncological patients as a complementary treatment to mitigate some adverse side-effects of antitumor treatments. However, a widespread concern exists about the possibility that the cytoprotective effect of Nrf2 activation may confer drug resistance to cancer cells or at least reduce the efficacy of antitumor agents. In this study, the effect of low ozone concentrations on tamoxifen-treated MCF7 human breast cancer cells has been investigated in vitro by histochemical and molecular techniques. Results demonstrated that cell viability, proliferation and migration were generally similar in tamoxifen-treated cells as in cells concomitantly treated with tamoxifen and ozone. Notably, low ozone concentrations were unable to overstimulate the antioxidant response through the Nfr2 pathway, thus excluding a possible ozone-driven cytoprotective effect that would lead to increased tumor cell survival during the antineoplastic treatment. These findings, though obtained in an in vitro model, support the hypothesis that low ozone concentrations do not interfere with the tamoxifen-induced effects on breast cancer cells.