New insights on the role of autophagy in the pathogenesis and treatment of melanoma

The impact of nanomaterials on autophagy across health and disease conditions

Autophagy, a catabolic process integral to cellular homeostasis, is constitutively active under physiological and stress conditions. The role of autophagy as a cellular defense response becomes particularly evident upon exposure to nanomaterials (NMs), especially environmental nanoparticles (NPs) and nanoplastics (nPs). This has positioned autophagy modulation at the forefront of nanotechnology-based therapeutic interventions. While NMs can exploit autophagy to enhance therapeutic outcomes, they can also trigger it as a pro-survival response against NP-induced toxicity. Conversely, a heightened autophagy response may also lead to regulated cell death (RCD), in particular autophagic cell death, upon NP exposure. Thus, the relationship between NMs and autophagy exhibits a dual nature with therapeutic and environmental interventions. Recognizing and decoding these intricate patterns are essential for pioneering next-generation autophagy-regulating NMs. This review delves into the present-day therapeutic potential of autophagy-modulating NMs, shedding light on their status in clinical trials, intervention of autophagy in the therapeutic applications of NMs, discusses the potency of autophagy for application as early indicator of NM toxicity.

Isoalantolactone exerts anti-melanoma effects via inhibiting PI3K/AKT/mTOR and STAT3 signaling in cell and mouse models

BACKGROUND AND AIM

Although the anti-cancer activity of isoalantolactone (IATL) has been extensively studied, the anti-melanoma effects of IATL are still unknown. Here, we have investigated the anti-melanoma effects and mechanism of action of IATL. MTT and crystal violet staining assays were performed to detect the inhibitory effect of IATL on melanoma cell viability. Apoptosis and cell cycle arrest induced by IATL were examined using flow cytometry. The molecular mechanism of IATL was explored by Western blotting, confocal microscope analysis, molecular docking, and cellular thermal shift assay (CETSA). A B16F10 allograft mouse model was constructed to determine the anti-melanoma effects of IATL in vivo. The results showed that IATL exerted anti-melanoma effects in vitro and in vivo. IATL induced cytoprotective autophagy in melanoma cells by inhibiting the PI3K/AKT/mTOR signaling. Moreover, IATL inhibited STAT3 activation both in melanoma cells and allograft tumors not only by binding to the SH2 domain of STAT3 but also by suppressing the activity of its upstream kinase Src. These findings demonstrate that IATL exerts anti-melanoma effects via inhibiting the STAT3 and PI3K/AKT/mTOR signaling pathways, and provides a pharmacological basis for developing IATL as a novel phytotherapeutic agent for treating melanoma clinically.

Emerging dimensions of autophagy in melanoma

Macroautophagy/autophagy has previously been regarded as simply a way for cells to deal with nutrient emergency. But explosive work in the last 15 years has given increasingly new knowledge to our understanding of this process. Many of the functions of autophagy that are unveiled from recent studies, however, cannot be reconciled with this conventional view of cell survival but, instead, point to autophagy being integrally involved at a deeper level of cell biology, playing a critical role in maintaining homeostasis and promoting an integrated stress/immune response. The new appreciation of the role of autophagy in the evolutionary trajectory of cancer and cancer interaction with the immune system provides a mechanistic framework for understanding the clinical benefits of autophagy-based therapies. Here, we examine current knowledge of the mechanisms and functions of autophagy in highly plastic and aggressive melanoma as a model disease of human malignancy, while highlighting emerging dimensions indicating that autophagy is at play beyond its classical face.Abbreviation: AMBRA1: autophagy and beclin 1 regulator 1; AMPK: AMP-activated protein kinase; ATF4: activating transcription factor 4; ATG: autophagy related; BRAF: B-Raf proto-oncogene, serine/threonine kinase; CAFs: cancer-associated fibroblasts; CCL5: C-C motif chemokine ligand 5; CQ: chloroquine; CRISPR: clustered regularly interspaced short palindromic repeats; CTLA4: cytotoxic T-lymphocyte associated protein 4; CTL: cytotoxic T lymphocyte; DAMPs: danger/damage-associated molecular patterns; EGFR: epidermal growth factor receptor; EIF2A/eIF2α: eukaryotic translation initiation factor 2A; EIF2AK3/PERK: eukaryotic translation initiation factor 2 alpha kinase 3; ER: endoplasmic reticulum; FITM2: fat storage inducing transmembrane protein 2; HCQ: hydroxychloroquine; ICB: immune checkpoint blockade; ICD: immunogenic cell death; LDH: lactate dehydrogenase; MAPK: mitogen-activated protein kinase; MTORC1: mechanistic target of rapamycin kinase complex 1; NDP52: nuclear dot protein 52; NFKB/NF-κ B: nuclear factor kappa B; NBR1: the neighbor of BRCA1; NK: natural killer; NRF1: nuclear respiratory factor 1; NSCLC: non-small-cell lung cancer; OPTN: optineurin; PDAC: pancreatic ductal adenocarcinoma; PDCD1/PD-1: programmed cell death 1; PPT1: palmitoyl-protein thioesterase 1; PTEN: phosphatase and tensin homolog; PTK2/FAK1: protein tyrosine kinase 2; RAS: rat sarcoma; SQSTM1/p62: sequestosome 1; STK11/LKB1: serine/threonine kinase 11; TAX1BP1: Tax1 binding protein 1; TFEB: transcription factor EB; TGFB/TGF-β: transforming growth factor beta; TMB: tumor mutational burden; TME: tumor microenvironment; TSC1: TSC complex subunit 1; TSC2: TSC complex subunit 2; ULK1: unc-51 like autophagy activating kinase 1; UVRAG: UV radiation resistance associated.

The Role of Autophagy in Human Uveal Melanoma and the Development of Potential Disease Biomarkers and Novel Therapeutic Paradigms

Autophagy is a form of programmed cell degradation that enables the maintenance of homeostasis in response to extracellular stress stimuli. Autophagy is primarily activated by starvation and mediates the degradation, removal, or recycling of cell cytoplasm, organelles, and intracellular components in eukaryotic cells. Autophagy is also involved in the pathogenesis of human diseases, including several cancers. Human uveal melanoma (UM) is the primary intraocular malignancy in adults and has an extremely poor prognosis; at present there are no effective therapies. Several studies have suggested that autophagy is important in UM. By understanding the mechanisms of activation of autophagy in UM it may be possible to develop biomarkers to provide more definitive disease prognoses and to identify potential drug targets for the development of new therapeutic strategies. This article reviews the current information regarding autophagy in UM that could facilitate biomarker and drug development.

Inhibition of Autophagy Aggravates Arachis hypogaea L. Skin Extracts-Induced Apoptosis in Cancer Cells

The skin of Arachis hypogaea L. (peanut or groundnut) is a rich source of polyphenols, which have been shown to exhibit a wider spectrum of noteworthy biological activities, including anticancer effects. However, the anticancer activity of peanut skin extracts against melanoma and colorectal cancer (CRC) cells remains elusive. In this study, we systematically investigated the cytotoxic, antiproliferative, pro-apoptotic, and anti-migration effects of peanut skin ethanolic extract and its fractions on melanoma and CRC cells. Cell viability results showed that the ethyl acetate fraction (AHE) of peanut skin ethanolic crude extract and one of the methanolic fractions (AHE-2) from ethyl acetate extraction exhibited the highest cytotoxicity against melanoma and CRC cells but not in nonmalignant human skin fibroblasts. AHE and AHE-2 effectively modulated the cell cycle-related proteins, including the suppression of cyclin-dependent kinase 4 (CDK4), cyclin-dependent kinase 6 (CDK6), phosphorylation of Retinoblastoma (p-Rb), E2F1, Cyclin A, and activation of tumor suppressor p53, which was associated with cell cycle arrest and paralleled their antiproliferative efficacies. AHE and AHE-2 could also induce caspase-dependent apoptosis and inhibit migration activities in melanoma and CRC cells. Moreover, it is noteworthy that autophagy, manifested by microtubule-associated protein light chain 3B (LC3B) conversion and the aggregation of GFP-LC3, was detected after AHE and AHE-2 treatment and provided protective responses in cancer cells. Significantly, inhibition of autophagy enhanced AHE- and AHE-2-induced cytotoxicity and apoptosis. Together, these findings not only elucidate the anticancer potential of peanut skin extracts against melanoma and CRC cells but also provide a new insight into autophagy implicated in peanut skin extracts-induced cancer cell death.

Assessment of Autophagy in Tumor Cells of Human Skin Melanoma of Different Stages

High levels of autophagy can increase the viability of tumor cells as well as their resistance to chemotherapy. Evaluation of the dynamics of autophagy processes at different stages of carcinogenesis can extend our understanding of melanoma pathogenesis to develop new therapeutic approaches. We performed a comparative study of tumor cell autophagy in stages II and III human skin melanoma. Tumor cells were characterized by high content of structures associated with autophagy (autophagosomes and autolysosomes). In stage III melanoma characterized by the presence of regional metastases in the lymph nodes, tumor cells showed higher expression of the autophagy marker protein LC3beta in comparison with stage II melanoma cells, which can indicate the involvement of autophagy processes in tumor progression and the formation of metastases in the lymph nodes.

The association and application of sonodynamic therapy and autophagy in diseases

Sonodynamic therapy (SDT) is a new non-invasive treatment method proposed based on photodynamic therapy (PDT). It has advantages such as high precision, strong tissue penetration, minimal side effects, and good patient compliance. With the maturation of nanomedicine, the application of nanosonosensitizers has further propelled the development of SDT. In recent years, people have developed many new types of sonosensitizers and explored the mechanisms of SDT. Among them, the studies about the relationship between autophagy and SDT have attracted increasing attention. After the SDT, cells usually undergo autophagy as a self-protective mechanism to resist external stimuli and reduce cell damage, which is beneficial for the treatment of atherosclerosis (AS), diabetes, and myocardial infarction but counterproductive in cancer treatment. However, under certain treatment conditions, excessive upregulation of autophagy can also promote cell death, which is beneficial for cancer treatment. This article reviews the latest research progress on the relationship between SDT and autophagy in cancers, AS, diabetes, and myocardial infarction. We also discuss and propose the challenges and prospects in enhancing SDT efficacy by regulating autophagy, with the hope of promoting the development of this promising therapeutic approach.

Evaluating the Serum Levels of Beclin-1 and Mammalian/Mechanistic Target of Rapamycin (mTOR) in Three Different Professional Categories

BACKGROUND

The possible associations between occupational factors and autophagy - a catabolic process that is evolutionarily conserved and serves as a vital cornerstone in maintaining cellular balance - remain largely unexplored.

OBJECTIVES

We assessed serum levels of beclin-1, a principal effector of autophagy, and the mammalian/mechanistic target of rapamycin (mTOR), a protein recognized for its part in suppressing autophagy, within a group of healthy individuals hailing from three different professional fields, each characterized by its unique working conditions.

METHODS

A total of 60 men were recruited from three distinct occupational categories: airline pilots, construction laborers, and fitness trainers. Each group consisted of 20 subjects who were selected during routine occupational health appointments. Serum levels of beclin-1 and mTOR were measured using commercially available immunoassays and compared among the three categories.

RESULTS

Fitness instructors had the highest concentration of beclin-1 (3.1 ± 0.9 ng/mL). Construction workers followed with a mean of 2.4 ± 0.4 ng/mL, while airline pilots had the lowest levels at 1.9 ± 0.5 ng/mL (one-way analysis of variance, P < 0.001). In terms of mTOR levels, construction workers had the highest concentration (5.9 ± 1.9 ng/mL), followed by airline pilots (4.4 ± 1.7 ng/mL). Fitness instructors, on the other hand, had the lowest mTOR levels (3.5 ± 1.2 ng/mL; one-way analysis of variance, P < 0.001).

CONCLUSIONS

Serum levels of autophagy biomarkers can vary among healthy individuals based on their professional roles. Considering the crucial function autophagy serves in both health and disease, further investigations are crucial to deepen our comprehension of the potential implications of autophagy in the field of occupational medicine.

Autophagy in BRAF-mutant cutaneous melanoma: recent advances and therapeutic perspective

Macroautophagy, hereafter referred to as autophagy, represents a highly conserved catabolic process that maintains cellular homeostasis. At present, the role of autophagy in cutaneous melanoma (CM) is still controversial, since it appears to be tumor-suppressive at early stages of malignant transformation and cancer-promoting during disease progression. Interestingly, autophagy has been found to be often increased in CM harboring BRAF mutation and to impair the response to targeted therapy. In addition to autophagy, numerous studies have recently conducted in cancer to elucidate the molecular mechanisms of mitophagy, a selective form of mitochondria autophagy, and secretory autophagy, a process that facilitates unconventional cellular secretion. Although several aspects of mitophagy and secretory autophagy have been investigated in depth, their involvement in BRAF-mutant CM biology has only recently emerged. In this review, we aim to overview autophagy dysregulation in BRAF-mutant CM, along with the therapeutic advantages that may arise from combining autophagy inhibitors with targeted therapy. In addition, the recent advances on mitophagy and secretory autophagy involvement in BRAF-mutant CM will be also discussed. Finally, since a number of autophagy-related non-coding RNAs (ncRNAs) have been identified so far, we will briefly discussed recent advances linking ncRNAs to autophagy regulation in BRAF-mutant CM.

A comprehensive signature based on endoplasmic reticulum stress-related genes in predicting prognosis and immunotherapy response in melanoma

Melanoma is considered as one of the most invasion types of skin cancer with high mortality rates. Although combination of immune checkpoint therapy with local surgical excision provide a novel promising therapeutic strategies, the overall prognosis of melanoma patients remains unsatisfactory. Endoplasmic reticulum (ER) stress, a process of protein misfolding and undue accumulation, has been proven to play an indispensable regulatory role in tumor progression and tumor immunity. However, whether the signature based ER genes has predictive value for the prognosis and immunotherapy of melanoma has not been systematically manifested. In this study, the LASSO regression and multivariate Cox regression were applied to construct a novel signature for predicting melanoma prognosis both in the training and testing set. Intriguingly, we found that patients endowed with high- and low-risk scores displayed differences in clinicopathologic classification, immune cell infiltration level, tumor microenvironment, and immune checkpoint treatment response. Subsequently, based on molecular biology experiments, we validated that silencing the expression of RAC1, an ERG composed of the risk signature, could restrain the proliferation and migration, promote apoptosis, as well as increase the expression of PD-1/PD-L1 and CTLA4 in melanoma cells. Taken together, the risk signature was regarded as promising predictors for melanoma prognosis and might provide prospective strategies to ameliorate patients' response to immunotherapy.

Autophagy modulation in breast cancer utilizing nanomaterials and nanoparticles

Autophagy regenerates cellular nutrients, recycles metabolites, and maintains hemostasis through multistep signaling pathways, in conjunction with lysosomal degradation mechanisms. In tumor cells, autophagy has been shown to play a dual role as both tumor suppressor and tumor promoter, leading to the discovery of new therapeutic strategies for cancer. Therefore, regulation of autophagy is essential during cancer progression. In this regard, the use of nanoparticles (NPs) is a promising technique in the clinic to modulate autophagy pathways. Here, we summarized the importance of breast cancer worldwide, and we discussed its classification, current treatment strategies, and the strengths and weaknesses of available treatments. We have also described the application of NPs and nanocarriers (NCs) in breast cancer treatment and their capability to modulate autophagy. Then the advantages and disadvantaged of NPs in cancer therapy along with future applications will be disscussed. The purpose of this review is to provide up-to-date information on NPs used in breast cancer treatment and their impacts on autophagy pathways for researchers.

Shining Light on Autophagy in Skin Pigmentation and Pigmentary Disorders

Autophagy is a vital process for cell survival and it preserves homeostasis by recycling or disassembling unnecessary or dysfunctional cellular constituents. Autophagy ameliorates skin integrity, regulating epidermal differentiation and constitutive pigmentation. It induces melanogenesis and contributes to skin color through melanosome turnover. Autophagy activity is involved in skin phenotypic plasticity and cell function maintenance and, if altered, it concurs to the onset and/or progression of hypopigmentary and hyperpigmentary disorders. Overexpression of autophagy exerts a protective role against the intrinsic metabolic stress occurring in vitiligo skin, while its dysfunction has been linked to the tuberous sclerosis complex hypopigmentation. Again, autophagy impairment reduces melanosome degradation by concurring to pigment accumulation characterizing senile lentigo and melasma. Here we provide an updated review that describes recent findings on the crucial role of autophagy in skin pigmentation, thus revealing the complex interplay among melanocyte biology, skin environment and autophagy. Hence, targeting this process may also represent a promising strategy for treating pigmentary disorders.

Autophagy: Guardian of Skin Barrier

Autophagy is a major degradation pathway that removes harmful intracellular substances to maintain homeostasis. Various stressors, such as starvation and oxidative stress, upregulate autophagy, and the dysregulation of autophagy is associated with various human diseases, including cancer and skin diseases. The skin is the first defense barrier against external environmental hazards such as invading pathogens, ultraviolet rays, chemical toxins, and heat. Although the skin is exposed to various stressors that can activate autophagy, the roles of autophagy in the skin have not yet been fully elucidated. Accumulating evidence suggests that autophagy is closely associated with pathogenesis and the treatment of immune-related skin diseases. In this study, we review how autophagy interacts with skin cells, including keratinocytes and immune cells, enabling them to successfully perform their protective functions by eliminating pathogens and maintaining skin homeostasis. Furthermore, we discuss the implications of autophagy in immune-related skin diseases, such as alopecia areata, psoriasis, and atopic dermatitis, and suggest that a combination of autophagy modulators with conventional therapies may be a better strategy for the treatment of these diseases.

Lithium Enhances Autophagy and Cell Death in Skin Melanoma: An Ultrastructural and Immunohistochemical Study

Lithium is an inhibitor of glycogen synthase kinase 3 beta, which is traditionally used in the treatment of bipolar disorders and has antitumor effects. The aim of the current study was to determine if lithium salt causes autophagy and apoptosis in skin melanoma cells to enhance cell death. Light microscopy, transmission electron microscopy, immunohistochemistry, and immunofluorescence were used to study the mechanism of action of lithium carbonate in B16 melanoma cells in vivo. Proliferating cell nuclear antigen immunofluorescence assay revealed that the proliferation of B16 melanoma cells was suppressed by lithium treatment for 7 days. Electron microscopy demonstrated a significant increase in the number of autophagic vacuoles in lithium-treated cells relative to control. In addition, levels of autophagy markers LC3 beta and LAMP1 found in lithium-treated tumor xenografts were higher than levels of these markers in the control tumors. Lithium induced caspase-3 expression and apoptotic cell death in tumor cells. Thus, lithium carbonate is the compound that inhibits cell proliferation and stimulates cell death in melanoma cells through induction of autophagy and apoptosis. Stimulation of autophagy by lithium could contribute to the development of autophagic cell death in tumor cells.

Preclinical Development of Seriniquinones as Selective Dermcidin Modulators for the Treatment of Melanoma

The bioactive natural product seriniquinone was discovered as a potential melanoma drug, which was produced by the as-yet-undescribed marine bacterium of the rare genus Serinicoccus. As part of a long-term research program aimed at the discovery of new agents for the treatment of cancer, seriniquinone revealed remarkable in vitro activity against a diversity of cancer cell lines in the US National Cancer Institute 60-cell line screening. Target deconvolution studies defined the seriniquinones as a new class of melanoma-selective agents that act in part by targeting dermcidin (DCD). The targeted DCD peptide has been recently examined and defined as a “pro-survival peptide” in cancer cells. While DCD was first isolated from human skin and thought to be only an antimicrobial peptide, currently DCD has been also identified as a peptide associated with the survival of cancer cells, through what is believed to be a disulfide-based conjugation with proteins that would normally induce apoptosis. However, the significantly enhanced potency of seriniquinone was of particular interest against the melanoma cell lines assessed in the NCI 60-cell line panel. This observed selectivity provided a driving force that resulted in a multidimensional program for the discovery of a usable drug with a new anticancer target and, therefore, a novel mode of action. Here, we provided an overview of the discovery and development efforts to date.

Oxidative Stress and Autophagy as Key Targets in Melanoma Cell Fate

Melanoma originates from the malignant transformation of melanocytes and is one of the most aggressive forms of cancer. The recent approval of several drugs has increased the chance of survival although a significant subset of patients with metastatic melanoma do not show a long-lasting response to these treatments. The complex cross-talk between oxidative stress and the catabolic process autophagy seems to play a central role in all aspects of melanoma pathophysiology, from initiation to progression and metastasis, including drug resistance. However, determining the fine role of autophagy in cancer death and in response to redox disruption is still a fundamental challenge in order to advance both basic and translational aspects of this field. In order to summarize the interactions among reactive oxygen and nitrogen species, autophagy machinery and proliferation/growth/death/apoptosis/survival, we provide here a narrative review of the preclinical evidence for drugs/treatments that modulate oxidative stress and autophagy in melanoma cells. The significance and the potential for pharmacological targeting (also through multiple and combination approaches) of these two different events, which can contribute independently or simultaneously to the fate of melanoma, may help to define new processes and their interconnections underlying skin cancer biology and unravel new reliable approaches.

The Challenging Melanoma Landscape: From Early Drug Discovery to Clinical Approval

Melanoma is recognized as the most dangerous type of skin cancer, with high mortality and resistance to currently used treatments. To overcome the limitations of the available therapeutic options, the discovery and development of new, more effective, and safer therapies is required. In this review, the different research steps involved in the process of antimelanoma drug evaluation and selection are explored, including information regarding in silico, in vitro, and in vivo experiments, as well as clinical trial phases. Details are given about the most used cell lines and assays to perform both two- and three-dimensional in vitro screening of drug candidates towards melanoma. For in vivo studies, murine models are, undoubtedly, the most widely used for assessing the therapeutic potential of new compounds and to study the underlying mechanisms of action. Here, the main melanoma murine models are described as well as other animal species. A section is dedicated to ongoing clinical studies, demonstrating the wide interest and successful efforts devoted to melanoma therapy, in particular at advanced stages of the disease, and a final section includes some considerations regarding approval for marketing by regulatory agencies. Overall, considerable commitment is being directed to the continuous development of optimized experimental models, important for the understanding of melanoma biology and for the evaluation and validation of novel therapeutic strategies.

Preclinical Study of Immunological Isoxazole Derivatives as a Potential Support for Melanoma Chemotherapy

(1) Background: Melanoma is an aggressive neoplasm derived from melanocyte precursors with a high metastatic potential. Responses to chemotherapy and immunotherapy for melanoma remain weak, underlining the urgent need to develop new therapeutic strategies for the treatment of melanoma. (2) Methods: The viability of NHDF and A375 cell cultures after the administration of the tested isoxazole derivatives was assessed after 24-h and 48-h incubation periods with the test compounds in the MTT test. ROS and NO scavenging analyses, a glycoprotein-P activity analysis, a migration assay, a test of apoptosis, and a multiple-criteria decision analysis were also performed. (3) Results: All compounds that were tested resulted in a slower migration of melanoma neoplastic cells. The mechanism of the antitumor activity of the tested compounds was confirmed-i.e., the pro-apoptotic activity of the compounds in A375 cell cultures. Compound O7K qualified for further research. (4) Conclusions: All the tested compounds inhibited the formation of melanoma metastases and demonstrated the ability to reduce the risk of developing drug resistance in the tumor. The MCDA results showed that O7K showed the strongest antitumor activity.