Role of ROS‑mediated autophagy in melanoma (Review)

The Role of Intermittent Fasting in the Activation of Autophagy Processes in the Context of Cancer Diseases

Intermittent fasting (IF) is a dietary approach that influences key metabolic pathways, including autophagy-a crucial mechanism in maintaining cellular homeostasis. Autophagy plays a dual role in oncogenesis, acting both as a tumor suppressor and a survival mechanism under metabolic stress. IF has shown potential for reducing cancer risk and enhancing therapeutic efficacy by sensitizing tumor cells to chemotherapy and radiotherapy. However, its effects depend heavily on the type and stage of cancer. Potential risks, such as excessive weight loss and malnutrition, require careful evaluation. Further clinical studies are needed to optimize IF protocols as adjuncts to cancer therapy. This review discusses autophagy mechanisms induced by IF, their therapeutic implications in oncology, and the limitations of this dietary strategy.

Bmal1 upregulates ATG5 expression to promote autophagy in skin cutaneous melanoma

BACKGROUND

Skin cutaneous melanoma (SKCM) is a highly aggressive and malignant tumor that arises from the malignant transformation of melanocytes. In light of the limitations of existing treatment modalities, there is a pressing need to identify new drug targets for SKCM. Aryl-hydrocarbon receptor nuclear translocator-like (ARNTL), also known as Bmal1, is a gene that has been linked to the onset and progression of cancer. However, its role in SKCM remains understudied.

METHODS

The expression of Bmal1 mRNA and protein was detected using TCGA, GTEx, CCLE, and ULCAN databases. Moreover, survival analysis was performed to investigate the association between Bmal1 and immune invasion and gene expression in immune infiltrating cells via CIBERSORT, R programming, TIMER, Sangerbox, Kaplan-Meier. The study also explored the role of proteins associated with Bmal1 by using R programming and databases (STRING and GSEA). Both in vitro and in vivo studies were conducted to examine the potential role of Bmal1 in SKCM.

RESULTS

Compared to normal tissues, the expression level of Bmal1 was significantly reduced in SKCM. Which has been associated with its poor prognosis. Similarly, its expression in SKCM was substantially correlated with immune infiltration, while biogenic analysis indicated that it could potentially influence the tumor immune microenvironment (TME) by influencing tumor-associated neutrophils (TANs). Moreover, Bmal1 overexpression suppressed the proliferation and invasion of melanoma cells and enhanced apoptosis, migration, and cell colony formation.

CONCLUSION

This study concluded that Bmal1 is a novel biomarker that functions as both a diagnostic and prognostic indicator for the progression of SKCM.

Dual intervention of Boeravinone B and Chebulinic Acid mitigates BHT-Induced toxicity in HepG2 cells: modulating apoptosis and autophagy

Butylated Hydroxytoluene (BHT) is found to exert cellular toxicity through induction of oxidative stress although being used as antioxidant in many food products. This study investigates the protective effects of two herbal compounds Boeravinone B (BB) and Chebulinic acid (CA) in combination (B4C3 i.e. BB 4 µg/mL and CA 3 µg/mL). Key findings revealed that BHT exerted toxicity through induction of ROS (234.47 a.u.) and RNS (0.042 µM/mL), but B4C3 has significantly reduced it (115.46 a.u. and 0.018 µM/mL respecctively). BHT exposure raised the activities of antioxidant enzymes such as SOD (70.9%), CAT (7.08 units/mL), GPX (1.21 units/mL), levels of protein carbonyls (3.52 units/mg) and lipid peroxides (418.34%). Whereas treatment with B4C3 decreased the levels of SOD (29.92%), CAT (3.12 units/mL), GPX (0.36 units/mL), protein carbonyls (0.91 units/mg of protein) and lipid peroxides (106.67%) during BHT exposure. It was found that 20.56% cells were apoptotic while 73.83% were autophagic during BHT treatment. However, proposed phytotherapy rescued the cells from apoptotic and autophagic death and supported cell growth which was confirmed by RT-PCR and growth analysis. Collectively, B4C3 offered a significant protection against BHT-induced cellular damage, suggesting its potential as therapeutic agents for oxidative stress-related hepatotoxicity.

Current Insights into the Role of UV Radiation-Induced Oxidative Stress in Melanoma Pathogenesis

Cutaneous melanoma accounts for the majority of skin cancer-related deaths, and its incidence increases each year. The growing number of melanoma cases, especially in advanced stages, poses a significant socio-medical challenge throughout the world. Extensive research on melanoma pathogenesis identifies UV radiation as the most important factor in melanocytic transformation. Oxidative effects of UV irradiation exert their influence on melanoma pathogenesis primarily through modification of nucleic acids, proteins, and lipids, further disrupting cellular signaling and cell cycle regulation. Its effects extend beyond melanocytes, leading to immunosuppression in the exposed skin tissue, which consequently creates conditions for immune surveillance evasion and further progression. In this review, we focus on the specific molecular changes observed in the UV-dependent oxidative stress environment and their biological consequences in the course of the disease, which have not been considered in previous reviews on melanoma. Nonetheless, data show that the exact role of oxidative stress in melanoma initiation and progression remains unclear, as it affects cancerous cells differently depending on the specific context. A better understanding of the pathophysiological basis of melanoma development holds promise for identifying potential targets, which could lead to effective melanoma prevention strategies.

Integrative analysis of autophagy-related genes reveals that CAPNS1 is a novel prognostic biomarker and promotes the malignancy of melanoma via Notch signaling pathway

Skin cutaneous melanoma (SKCM) is a highly fatal form of skin cancer that develops from the malignant transformation of epidermal melanocytes. There is substantial evidence linking autophagy to cancer etiology and immunotherapy efficacy. This study aimed to conduct a comprehensive analysis of autophagy-related genes (ARGs) using TCGA datasets and further explore the potential function of critical ARGs in SKCM progression. We performed comprehensive bioinformatics analysis uses the TCGA dataset. RT-PCR was applied to examine the expression of CAPNS1 in SKCM cells. Lost-of-function experiments were performed to detect the expression of the related proteins. In this search, we screed 70 differentially expressed autophagy-related genes (DE-ARGs), including 33 up-DE-ARGs and 37 down-DE-ARGs. Enrichment assays revealed that these 70 DE-ARGs may exert influence on critical cellular processes such as autophagy, protein kinase activity, and signaling pathways, impacting cell growth, differentiation, survival, and tumor development. Then, we further explore the prognostic value of 70 DE-ARGs and confirmed 18 survival-related DE-ARGs in SKCM patients. Nearly all the 18 DE-ARGs' methylation was negatively correlated with their corresponding expression in SKCM. The 12 survival-related DE-ARGs were used to develop a unique predictive model that effectively classified SKCM patients into high- and low-risk groups with regard to overall survival. Furthermore, tumor environment analysis indicated that the risk score was associated with several immune cells. Among the 12 survival-related DE-ARGs, our attention focused on CAPNS1 which was highly expressed in SKCM patients and predicted a poor prognosis. In addition, we confirmed that knockdown of CAPNS1 distinctly suppressed the proliferation, metastasis and EMT of SKCM cells, and promoted autophagy via regulating Notch signaling pathway. Overall, this study enhances our understanding of the intricate molecular landscape of SKCM progression and presents promising avenues for future research and clinical applications.

Sunset Yellow protects against oxidative damage and exhibits chemoprevention in chemically induced skin cancer model

Skin cancer and other skin-related inflammatory pathologies are rising due to heightened exposure to environmental pollutants and carcinogens. In this context, natural products and repurposed compounds hold promise as novel therapeutic and preventive agents. Strengthening the skin's antioxidant defense mechanisms is pivotal in neutralizing reactive oxygen species (ROS) and mitigating oxidative stress. Sunset Yellow (SY) exhibits immunomodulatory characteristics, evidenced by its capacity to partially inhibit the secretion of proinflammatory cytokines, regulate immune cell populations, and modulate the activation of lymphocytes. This study aimed to investigate the antioxidant and anti-genotoxic properties of SY using in-silico, in vitro, and physiochemical test systems, and to further explore its potential role in 7,12-dimethylbenz(a) anthracene (DMBA)/ 12-o-tetradecanoylphorbol-13-acetate (TPA)-induced two-stage skin carcinogenesis. In vitro experiments showed that pre-treatment of SY significantly enhanced the cell viability of HaCaT cells when exposed to tertiary-Butyl Hydrogen Peroxide (tBHP). This increase was accompanied by reduced ROS levels, restoration of mitochondrial membrane potential, and notable reduction in DNA damage in (SY + tBHP) treated cells. Mechanistic investigations using DPPH chemical antioxidant activity test and potentiometric titrations confirmed SY's antioxidant properties, with a standard reduction potential (E o ) of 0.211 V. Remarkably, evaluating the effect of topical application of SY in DMBA/TPA-induced two-step skin carcinogenesis model revealed dose-dependent decreases in tumor latency, incidence, yield, and burden over 21-weeks. Furthermore, computational analysis and experimental validations identified GSK3β, KEAP1 and EGFR as putative molecular targets of SY. Collectively, our findings reveal that SY enhances cellular antioxidant defenses, exhibits anti-genotoxic effects, and functions as a promising chemopreventive agent.

Naturally Derived Phenethyl Isothiocyanate Modulates Induction of Oxidative Stress via Its N-Acetylated Cysteine Conjugated form in Malignant Melanoma

Phenethyl isothiocyanate (PEITC) is a secondary metabolic product yielded upon the hydrolysis of gluconasturtiin and it is highly accumulated in the flowers of watercress. The aim of the current study was to assess the role of a naturally derived PEITC-enriched extract in the induction of oxidative stress and to evaluate its anti-melanoma potency through the regulation of its metabolism with the concurrent production of the N-acetyl cysteine conjugated by-product. For this purpose, an in vitro melanoma model was utilized consisting of human primary (A375) cells as well as metastatic (COLO-679) malignant melanoma cells together with non-tumorigenic immortalized keratinocytes (HaCaT). Cytotoxicity was assessed via the Alamar Blue assay whereas the antioxidant/prooxidant activity of PEITC was determined via spectrophotometric assays. Finally, kinetic characterization of the end-product of PEITC metabolism was monitored via UPLC coupled to a tandem mass spectrometry (MS/MS). Our results indicate that although PhEF showed very minor antioxidant activity in a cell-free system, in a cell-based system, it can modulate the activity of key enzyme(s) involved in cellular antioxidant defense mechanism(s). In addition, we have shown that PhEF induces lipid and protein oxidation in a concentration-dependent manner, while its cytotoxicity is not only dependent on PEITC itself but also on its N-acetylated cysteine conjugated form.

Cancer Metabolism: The Role of ROS in DNA Damage and Induction of Apoptosis in Cancer Cells

Cancer is a huge challenge for people worldwide. High reactive oxygen species (ROS) levels are a recognized hallmark of cancer and an important aspect of cancer treatment research. Abnormally elevated ROS levels are often attributable to alterations in cellular metabolic activities and increased oxidative stress, which affects both the development and maintenance of cancer. Moderately high levels of ROS are beneficial to maintain tumor cell genesis and development, while toxic levels of ROS have been shown to be an important force in destroying cancer cells. ROS has become an important anticancer target based on the proapoptotic effect of toxic levels of ROS. Therefore, this review summarizes the role of increased ROS in DNA damage and the apoptosis of cancer cells caused by changes in cancer cell metabolism, as well as various anticancer therapies targeting ROS generation, in order to provide references for cancer therapies based on ROS generation.

Tumor-homing bacterium-adsorbed liposomes encapsulating perfluorohexane/doxorubicin enhance pulsed-focused ultrasound for tumor therapy

Objective: To make up for the insufficient ultrasound ablation of tumors, the energy output or synergist is increased but faces the big challenge of normal tissue damage. In this study, we report a tumor-homing bacterium, Bifidobacterium bifidum (B. bifidum), adsorbing liposomes that encapsulate perfluorohexane (PFH) and doxorubicin (DOX) to enhance the pulsed-focused ultrasound (PFUS) for tumor therapy, so as to improve the efficacy, safety and controllability of ultrasound treatment. Methods: The PFH and DOX co-loaded cationic liposomal nanoparticles (CL-PFH-DOX-NPs) were prepared for ultrasound (US) imaging, cell-killing, and B. bifidum adsorption for the reactive oxygen species (ROS) testing. The aggregation of B. bifidum and CL-PFH-DOX-NPs is called tumor-homing aggregation (B. bifidum@CL-PFH-DOX-NPs) in this study, and the synergistic effects of B. bifidum@CL-PFH-DOX-NPs were analyzed in vivo. Results: Comprehensive studies validated that CL-PFH-DOX-NPs can enhance US imaging and cell-killing and B. bifidum can promote ROS, and B. bifidum@CL-PFH-DOX-NPs achieve PFUS synergism in vivo. Importantly, active homing of B. bifidum facilitated the delivery and retention of CL-PFH-DOX-NPs in tumors, reducing dispersion in normal tissues, achieving the targeting ability of B. bifidum@CL-PFH-DOX-NPs. The best sonication time was chosen according to the distribution of CL-PFH-DOX-NPs in vivo to achieve efficient therapy. Especially, B. bifidum@CL-PFH-DOX-NPs amplified cavitation and the immune-boosting effects. Conclusion: Multifunctional B. bifidum@CL-PFH-DOX-NPs were successfully constructed with well targeting, which not only realized US imaging monitoring, strong cavitation and complementary killing during PFUS, but also achieved immunity enhancement after PFUS. The combination of PFUS, B. bifidum and CL-PFH-DOX-NPs provides a new idea for the potential application of ultrasound therapy in solid tumors.