Molecular Mechanisms of Autophagy in Cancer Development, Progression, and Therapy

The RNA-binding protein ELAVL1 promotes Beclin1-mediated cellular autophagy and thus endometrial cancer development by affecting LncRNA-neat stability

Our study aims to investigate the roles of embryonic lethal abnormal vision-like 1 (ELAVL1) and long non-coding RNA (LncRNA) NEAT1 in endometrial cancer (EC), focusing on their underlying molecular mechanisms.We obtained EC cell lines (HEC-1A, Ishikawa, RL95-2, HEC-1B, and AN3CA) from ATCC. We used siRNAs (si-ELAVL1#1 and si-ELAVL1#2) and overexpression RNAs (OE ELAVL1 and OE-NEAT1) for knockdown or overexpression of ELAVL1 and LncRNA NEAT1. We also employed 3-MA (5mM) or rapamycin (100µM) to inhibit or promote autophagy. Moreover, we conducted RNA immunoprecipitation (RIP) assays to confirm the interaction between LncRNA NEAT1 and ELAVL1. Cell Counting Kit-8 (CCK-8) and transwell assays were utilized to assess cell proliferation and migration. Additionally, we measured the expression of ELAVL1 and Beclin1 through Western blotting and RT-qPCR.ELAVL1 was found to be highly expressed in EC. Furthermore, ELAVL1 promoted the proliferation, invasion, and migration of EC cells through the regulation of Beclin1-related pathways. RIP assays revealed a direct interaction between LncRNA NEAT1 and ELAVL1, with ELAVL1 stabilizing LncRNA NEAT1 mRNA in EC cells. Additionally, we observed that ELAVL1 influenced EC cell proliferation, invasion, and migration through the regulation of LncRNA NEAT1-mediated regulation of Beclin1 expression. Moreover, in an animal study, we determined that ELAVL1 influenced endometrial cancer tumor growth through its interaction with LncRNA NEAT1, which mediated Beclin1 expression in vivo.In summary, our study showed that ELAVL1 regulated the malignant behavior of endometrial cancer cells through the modulation of LncRNA NEAT1-mediated regulation of Beclin1 expression.

Polysaccharides as therapeutic vehicles in pancreatic cancer

Pancreatic cancer (PC) is highly aggressive, with rising incidence and mortality rates. It has significant therapy obstacles due to the limited clinical options, late-stage identification, dense tumor microenvironment (TME), and resistance to therapy. Recent advances might improve treatment consequences in therapy strategies that target important TME components. Moreover, new polymeric drug delivery techniques based on polysaccharides such as polymeric micelles, liposomes, and nanoparticles enhance the solubility of drugs, drug stability, and tumor-specific targeting, which increase the chances of circumventing resistance and improving the efficacy of treatment. Preclinical research has suggested that by modulating the TME and enhancing the efficacy of chemotherapy, polysaccharide-based therapy, such as RP02-1 and DPLL-functionalized amylose, may help treat PC.

Evaluation of autophagy related ATG4B gene, protein and miR-655-3p expression levels in endometrial cancer and hyperplasia

OBJECTIVE

The pathogenesis of endometrial cancer (EC) and hyperplasia is complex and poorly understood. Autophagy has emerged as a crucial aspect of this process.

METHODS

This study examines the role of autophagy in the pathogenesis of EC and hyperplasia by investigating the expression of the autophagy-related 4B cysteine peptidase (ATG4B) gene, protein, and miR-665-3p levels in patients compared to a control group. This cross-sectional case control study analyzed 90 endometrial tissues, including 30 tumors, 30 normal controls, and 30 hyperplasia, using quantitative reverse transcription polymerase chain reaction and Western blot to assess ATG4B gene and protein levels.

RESULTS

Higher ATG4B gene expression levels were found in the endometrial tissue of EC patients than in hyperplasia patients and controls. Furthermore, protein levels of ATG4B were also higher in EC and hyperplasia patients than in controls. ATG4B gene expression and protein levels were positively correlated in EC patients. However, in EC patients, miR-655-3p showed a significant negative correlation with the ATG4B gene and protein levels.

CONCLUSION

ATG4B gene and protein expression is elevated in EC tissue, suggesting their role as a tumor promoter. Evaluating their levels could serve as markers for monitoring EC progression and prognosis.

Role of Non-coding RNAs on the Radiotherapy Sensitivity and Resistance in Cancer Cells

Radiotherapy (RT) is an integral part of treatment management in cancer patients. However, one of the limitations of this treatment method is the resistance of cancer cells to radiotherapy. These restrictions necessitate the introduction of modalities for the radiosensitization of cancer cells. It has been shown that Noncoding RNAs (ncRNAs), along with modifiers, can act as radiosensitivity and radioresistant regulators in a variety of cancers by affecting double strand break (DSB), wnt signaling, glycolysis, irradiation induced apoptosis, ferroptosis and cell autophagy. This review will provide an overview of the latest research on the roles and regulatory mechanisms of ncRNA after RT in in vitro and preclinical researches.

Homogeneous Polyporus polysaccharide exerts anti-bladder cancer effects via autophagy induction

CONTEXT

Polyporus polysaccharide (PPS), the leading bioactive ingredient extracted from Polyporus umbellatus (Pers.) Fr. (Polyporaceae), has been demonstrated to exert anti-bladder cancer and immunomodulatory functions in macrophages.

OBJECTIVE

To explore the effects of homogeneous Polyporus polysaccharide (HPP) on the proliferation and autophagy of bladder cancer cells co-cultured with macrophages.

MATERIALS AND METHODS

MB49 bladder cancer cells and RAW264.7 macrophages were co-cultured with or without HPP intervention (50, 100, or 200 μg/mL) for 24 h. The cell counting kit-8 (CCK-8) assay and 5-ethynyl-2″-deoxyuridine (EdU) staining evaluated MB49 cell proliferation. Monodansylcadaverine (MDC) staining and transmission electron microscopy (TEM) observed autophagosomes. Western blotting detected the expression levels of autophagy-related proteins and PI3K/Akt/mTOR pathway proteins.

RESULTS

HPP inhibited the proliferation of MB49 cells co-cultured with RAW264.7 cells but not MB49 cells alone. HPP altered the expression of autophagy-related proteins and promoted the formation of autophagosomes in MB49 cells in the co-culture system. Autophagy inhibitors 3-methyladenine (3-MA) and chloroquine (CQ) not only antagonized HPP-induced autophagy but also attenuated the inhibitory effects of HPP on MB49 cell proliferation in the co-culture system. HPP or RAW264.7 alone was not sufficient to induce autophagy in MB49 cells. In addition, HPP suppressed the protein expression of the PI3K/Akt/mTOR pathway in MB49 cells in the co-culture system.

DISCUSSION AND CONCLUSIONS

HPP induced bladder cancer cell autophagy by regulating macrophages in the co-culture system, resulting in the inhibition of cancer cell proliferation. The PI3K/Akt/mTOR pathway was involved in HPP-induced autophagy in the co-culture system.

Curcumin enhances ATG3-dependent autophagy and inhibits metastasis in cervical carcinoma

Cervical carcinoma poses a significant health threat, with traditional treatments proving inadequate in advanced stages. Curcumin, a bioactive compound derived from turmeric, exhibits notable anti-inflammatory, antioxidant, and antineoplastic properties, potentially modulating autophagy, and metastasis in cancer cells. This study examines curcumin's impact on autophagy and metastasis in cervical carcinoma, focusing on its interaction with autophagy-related gene 3 (ATG3). SiHa and HeLa cervical carcinoma cell lines were treated with curcumin, ATG3 knockdown (shATG3), and their combination. Cell migration was evaluated via wound healing assays, while cell proliferation was evaluated with CCK-8 assays. LC3 expression was assessed using immunofluorescence and western blotting. Molecular docking simulations identified curcumin's binding interactions with key proteins. Curcumin and shATG3 significantly inhibited both cell migration and proliferation, with a synergistic effect observed when combined. LC3 expression was enhanced, indicating increased autophagy. Docking studies revealed curcumin's potential binding to MMP2, MMP9, TGF-β, ATG3, LC3, and p62, suggesting modulation of these pathways. The combination of curcumin and ATG3 knockdown significantly inhibited cervical carcinoma cell migration and proliferation, while also enhancing autophagy, supporting the potential of curcumin as a therapeutic agent for cervical carcinoma. Further clinical research is needed to validate these findings.

MiR-29a-laden extracellular vesicles efficiently induced apoptosis through autophagy blockage in HCC cells

BACKGROUND

In spite of significant advancements in theraputic modalities for hepatocellular carcinoma (HCC), there is still a high annual mortality rate with a rising incidence. Major challenges in the HCC clinical managment are related to the development of therapy resistance, and evasion of tumor cells apoptosis which leading unsatisfactory outcomes in HCC patients. Previous investigations have shown that autophagy plays crucial role in contributing to drug resistance development in HCC. Although, miR-29a is known to counteract authophagy, increasing evidence revealed a down-regulation of miR-29a in HCC patients which correlates with poor prognosis. Beside, evidences showed that miR-29a serves as a negative regulator of autophagy in other cancers. In the current study, we aim to investigate the impact of miR-29a on the autophagy and apoptosis in HCC cells using extracellular vesicles (EVs) as a natural delivery system given their potential in the miRNA delivery both in vitro and in vivo.

METHOD

Human Wharton's Jelly mesenchymal stromal cell-derived extracellular vesicles were lately isolated through 20,000 or 110,000 × g centrifugation (EV20K or EV110K, respectively), characterized by western blot (WB), scanning electron microscopy (SEM), and dynamic light scattering (DLS). miR-29a was subsequently loaded into these EVs and its loading efficiency was evaluated via RT-qPCR. Comprehensive in vitro and in vivo assessments were then performed on Huh-7 and HepG2 cell lines.

RESULTS

EV20K-miR-29a treatment significantly induces cell apoptosis and reduces both cell proliferation and colony formation in Huh-7 and HepG2 cell lines. In addition, LC3-II/LC3-I ratio was increased while the expression of key autophagy regulators TFEB and ATG9A were downregulated by this treatment. These findings suggest an effective blockade of autophagy by EV20K-miR-29a leading to apoptosis in the HCC cell lines through concomitant targeting of critical mediators within each pathway.

Targeting autophagy can synergize the efficacy of immune checkpoint inhibitors against therapeutic resistance: New promising strategy to reinvigorate cancer therapy

Immune checkpoints are a set of inhibitory and stimulatory molecules/mechanisms that affect the activity of immune cells to maintain the existing balance between pro- and anti-inflammatory signaling pathways and avoid the progression of autoimmune disorders. Tumor cells can employ these checkpoints to evade immune system. The discovery and development of immune checkpoint inhibitors (ICIs) was thereby a milestone in the area of immuno-oncology. ICIs stimulate anti-tumor immune responses primarily by disrupting co-inhibitory signaling mechanisms and accelerate immune-mediated killing of tumor cells. Despite the beneficial effects of ICIs, they sometimes encounter some degrees of therapeutic resistance, and thereby do not effectively act against tumors. Among multiple combination therapies have been introduced to date, targeting autophagy, as a cellular degradative process to remove expired organelles and subcellular constituents, has represented with potential capacities to overcome ICI-related therapy resistance. It has experimentally been illuminated that autophagy induction blocks the immune checkpoint molecules when administered in conjugation with ICIs, suggesting that autophagy activation may restrict therapeutic challenges that ICIs have encountered with. However, the autophagy flux can also provoke the immune escape of tumors, which must be considered. Since the conventional FDA-approved ICIs have designed and developed to target programmed cell death receptor/ligand 1 (PD-1/PD-L1) as well as cytotoxic T lymphocyte-associated molecule 4 (CTLA-4) immune checkpoint molecules, we aim to review the effects of autophagy targeting in combination with anti-PD-1/PD-L1- and anti-CTLA-4-based ICIs on cancer therapeutic resistance and tumor immune evasion.

Epithelial-mesenchymal plasticity in cancer: signaling pathways and therapeutic targets

Currently, cancer is still a leading cause of human death globally. Tumor deterioration comprises multiple events including metastasis, therapeutic resistance and immune evasion, all of which are tightly related to the phenotypic plasticity especially epithelial-mesenchymal plasticity (EMP). Tumor cells with EMP are manifest in three states as epithelial-mesenchymal transition (EMT), partial EMT, and mesenchymal-epithelial transition, which orchestrate the phenotypic switch and heterogeneity of tumor cells via transcriptional regulation and a series of signaling pathways, including transforming growth factor-β, Wnt/β-catenin, and Notch. However, due to the complicated nature of EMP, the diverse process of EMP is still not fully understood. In this review, we systematically conclude the biological background, regulating mechanisms of EMP as well as the role of EMP in therapy response. We also summarize a range of small molecule inhibitors, immune-related therapeutic approaches, and combination therapies that have been developed to target EMP for the outstanding role of EMP-driven tumor deterioration. Additionally, we explore the potential technique for EMP-based tumor mechanistic investigation and therapeutic research, which may burst vigorous prospects. Overall, we elucidate the multifaceted aspects of EMP in tumor progression and suggest a promising direction of cancer treatment based on targeting EMP.

Exploring Importance and Regulation of Autophagy in Cancer Stem Cells and Stem Cell-Based Therapies

Autophagy is a globally conserved cellular activity that plays a critical role in maintaining cellular homeostasis through the breakdown and recycling of cellular constituents. In recent years, there has been much emphasis given to its complex role in cancer stem cells (CSCs) and stem cell treatment. This study examines the molecular processes that support autophagy and how it is regulated in the context of CSCs and stem cell treatment. Although autophagy plays a dual role in the management of CSCs, affecting their removal as well as their maintenance, the intricate interaction between the several signaling channels that control cellular survival and death as part of the molecular mechanism of autophagy has not been well elucidated. Given that CSCs have a role in the development, progression, and resistance to treatment of tumors, it is imperative to comprehend their biological activities. CSCs are important for cancer biology because they also show a tissue regeneration model that helps with organoid regeneration. In other words, the manipulation of autophagy is a viable therapeutic approach in the treatment of cancer and stem cell therapy. Both synthetic and natural substances that target autophagy pathways have demonstrated promise in improving stem cell-based therapies and eliminating CSCs. Nevertheless, there are difficulties associated with the limitations of autophagy in CSC regulation, including resistance mechanisms and off-target effects. Thus, the regulation of autophagy offers a versatile strategy for focusing on CSCs and enhancing the results of stem cell therapy. Therefore, understanding the complex interactions between autophagy and CSC biology would be essential for creating therapeutic treatments that work in both regenerative medicine and cancer treatment.

Exploring the Antiproliferative and Modulatory Effects of 1-Methoxyisobrassinin on Ovarian Cancer Cells: Insights into Cell Cycle Regulation, Apoptosis, Autophagy, and Its Interactions with NAC

Ovarian cancer, a highly lethal malignancy among reproductive organ cancers, poses a significant challenge with its high mortality rate, particularly in advanced-stage cases resistant to platinum-based chemotherapy. This study explores the potential therapeutic efficacy of 1-methoxyisobrassinin (MB-591), a derivative of indole phytoalexins found in Cruciferae family plants, on both cisplatin-sensitive (A2780) and cisplatin-resistant ovarian cancer cells (A2780 cis). The findings reveal that MB-591 exhibits an antiproliferative effect on both cell lines, with significantly increased potency against cisplatin-sensitive cells. The substance induces alterations in the distribution of the cell cycle, particularly in the S and G2/M phases, accompanied by changes in key regulatory proteins. Moreover, MB-591 triggers apoptosis in both cell lines, involving caspase-9 cleavage, PARP cleavage induction, and DNA damage, accompanied by the generation of reactive oxygen species (ROS) and mitochondrial dysfunction. Notably, the substance selectively induces autophagy in cisplatin-resistant cells, suggesting potential targeted therapeutic applications. The study further explores the interplay between MB-591 and antioxidant N-acetylcysteine (NAC), in modulating cellular processes. NAC demonstrates a protective effect against MB-591-induced cytotoxicity, affecting cell cycle distribution and apoptosis-related proteins. Additionally, NAC exhibits inhibitory effects on autophagy initiation in cisplatin-resistant cells, suggesting its potential role in overcoming resistance mechanisms.

WITHDRAWN: The dysregulated autophagy in osteoarthritis: Revisiting molecular profile

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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 enhances the anticancer effect of Schisandrin B on head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is among the most common malignant tumors worldwide and has a poor prognosis. Autophagy regulation has been proposed as a possible treatment option for HNSCC. Schisandrin B (Sch B) exerts anticancer effects by regulating apoptosis and autophagy, but the anticancer effect of Sch B in HNSCC remains unclear. This study aimed to investigate the effects of Sch B on human Cal27 HNSCC cells and to further reveal its potential regulatory mechanisms. The anticancer effect of Sch B was evaluated in vitro by flow cytometry, clonogenic assays, and Western blot analysis. The regulatory mechanism of Sch B-induced apoptosis and autophagy was further explored by polymerase chain reaction, luciferase assay, and reactive oxygen species (ROS) detection. The results showed that Sch B significantly induced apoptosis and autophagy in Cal27 cells and that inhibition of autophagy enhanced the apoptotic effect of Sch B on Cal27 cells. Additionally, Sch B-activated autophagy in Cal27 cells was dependent on the nuclear factor-kappa B (NF-κB) pathway, and ROS acted as a regulator of the NF-B pathway. N-acetylcysteine, a scavenger of ROS, inhibited Sch B-dependent autophagy via the NF-κB pathway. Based on the results, Sch B is a potential therapeutic agent for HNSCC and activates the NF-κB pathway by increasing ROS production, which subsequently promotes autophagy in HNSCC cells. Therefore, the strategy of enhancing the anticancer effect of Sch B by inhibiting autophagy deserves further attention.

JSI-124 inhibits cell proliferation and tumor growth by inducing autophagy and apoptosis in murine malignant mesothelioma

Malignant pleural mesothelioma (MPM), mainly caused by asbestos exposure, has a poor prognosis and lacks effective treatment compared with other cancer types. The intracellular transcription factor signal transducer and activator of transcription 3 (STAT3) is overexpressed and hyperactivated in most human cancers. In this study, the role of STAT3 in murine MPM was examined. Inhibition of the Janus kinase 2 (JAK2)/STAT3 pathway with the selective inhibitor JSI-124 has an antitumor effect in murine MPM. Specifically, we demonstrated that JSI-124 inhibits murine MPM cell growth and induces apoptotic and autophagic cell death. Exposure of RN5 and AB12 cells to JSI-124 resulted in apoptosis via the Bcl-2 family of proteins. JSI-124 triggered autophagosome formation, accumulation, and conversion of LC3I to LC3II. Autophagy inhibitors, Chloroquine (CQ) and Bafilomycin A1 (Baf-A1), inhibited autophagy and sensitized RN5 and AB12 cells to JSI-124-induced apoptosis. Our data indicate that JSI-124 is a promising therapeutic agent for MPM treatment.

Targeting autophagy and beyond: Deconvoluting the complexity of Beclin-1 from biological function to cancer therapy

Beclin-1 is the firstly-identified mammalian protein of the autophagy machinery, which functions as a molecular scaffold for the assembly of PI3KC3 (class III phosphatidylinositol 3 kinase) complex, thus controlling autophagy induction and other cellular trafficking events. Notably, there is mounting evidence establishing the implications of Beclin-1 in diverse tumorigenesis processes, including tumor suppression and progression as well as resistance to cancer therapeutics and CSC (cancer stem-like cell) maintenance. More importantly, Beclin-1 has been confirmed as a potential target for the treatment of multiple cancers. In this review, we provide a comprehensive survey of the structure, functions, and regulations of Beclin-1, and we discuss recent advances in understanding the controversial roles of Beclin-1 in oncology. Moreover, we focus on summarizing the targeted Beclin-1-regulating strategies in cancer therapy, providing novel insights into a promising strategy for regulating Beclin-1 to improve cancer therapeutics in the future.

Piperine Induces Apoptosis and Autophagy in HSC-3 Human Oral Cancer Cells by Regulating PI3K Signaling Pathway

Currently, therapies for treating oral cancer have various side effects; therefore, research on treatment methods employing natural substances is being conducted. This study aimed to investigate piperine-induced apoptosis and autophagy in HSC-3 human oral cancer cells and their effects on tumor growth in vivo. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay demonstrated that piperine reduced the viability of HSC-3 cells and 4',6-diamidino-2-phenylindole staining, annexin-V/propidium iodide staining, and analysis of apoptosis-related protein expression confirmed that piperine induces apoptosis in HSC-3 cells. Additionally, piperine-induced autophagy was confirmed by the observation of increased acidic vesicular organelles and autophagy marker proteins, demonstrating that autophagy in HSC-3 cells induces apoptosis. Mechanistically, piperine induced apoptosis and autophagy by inhibiting the phosphatidylinositol-3-kinase (PI3K)/protein kinase B/mammalian target of rapamycin pathway in HSC-3 cells. We also confirmed that piperine inhibits oral cancer tumor growth in vivo via antitumor effects related to apoptosis and PI3K signaling pathway inhibition. Therefore, we suggest that piperine can be considered a natural anticancer agent for human oral cancer.

Induction of Apoptosis and Decrease of Autophagy in Colon Cancer Cells by an Extract of Lyophilized Mango Pulp

Previous studies have indicated that mango fruit has a chemopreventive capacity against colorectal cancer cells. The objective of this research was to evaluate the effect of an aqueous extract of lyophilized mango pulp (LMPE) on colon adenocarcinoma cells (SW480) and their metastatic derivatives (SW620) death and cellular invasion. DNA fragmentation was assessed by TUNEL assay; autophagy and expression of DR4 and Bcl-2 by flow cytometry; the expression of 35 apoptosis-related proteins and of matrix metalloproteinases 7 and 9 by immunodetection; and the invasive capacity of the cells by Boyden chamber. The results showed that LMPE at 30 mg/mL and 48 h of exposure results in DNA fragmentation and apoptosis in SW480 (p < 0.001) and SW620 (p < 0.01) cells. Additionally, LMPE decreased autophagy in the SW480 and SW620 cell lines (p < 0.001), which could sensitize them to the DNA damage generated by LMPE. The LMPE did not modulate the expression of matrix metalloproteinases 7 and 9, nor did it affect cellular invasion processes in the SW480 and SW620 cell lines. In conclusion, LMPE induces apoptosis and decreases autophagy in SW480 and SW620 cells.

Recent Advances in Cellular Signaling Interplay between Redox Metabolism and Autophagy Modulation in Cancer: An Overview of Molecular Mechanisms and Therapeutic Interventions

Autophagy is a fundamental homeostatic process in which certain cellular components are ingested by double-membrane autophagosomes and then degraded to create energy or to maintain cellular homeostasis and survival. It is typically observed in nutrient-deprived cells as a survival mechanism. However, it has also been identified as a crucial process in maintaining cellular homeostasis and disease progression. Normal cellular metabolism produces reactive oxygen (ROS) and nitrogen species at low levels. However, increased production causes oxidative stress, which can lead to diabetes, cardiovascular diseases, neurological disorders, and cancer. It was recently shown that maintaining redox equilibrium via autophagy is critical for cellular responses to oxidative stress. However, little is understood about the molecular cancer processes that connect to the control of autophagy. In cancer cells, oncogenic mutations, carcinogens, and metabolic reprogramming cause increased ROS generation and oxidative stress. Recent studies have suggested that increased ROS generation activates survival pathways that promote cancer development and metastasis. Moreover, the relationship between metabolic programming and ROS in cancer cells is involved in redox homeostasis and the malignant phenotype. Currently, while the signaling events governing autophagy and how redox homeostasis affects signaling cascades are well understood, very little is known about molecular events related to autophagy. In this review, we focus on current knowledge about autophagy modulation and the role of redox metabolism to further the knowledge of oxidative stress and disease progression in cancer regulation. Therefore, this review focuses on understanding how oxidation/reduction events fine-tune autophagy to help understand how oxidative stress and autophagy govern cancer, either as processes leading to cell death or as survival strategies for maintaining redox homeostasis in cancer.

Recent Update and Drug Target in Molecular and Pharmacological Insights into Autophagy Modulation in Cancer Treatment and Future Progress

Recent evidence suggests that autophagy is a governed catabolic framework enabling the recycling of nutrients from injured organelles and other cellular constituents via a lysosomal breakdown. This mechanism has been associated with the development of various pathologic conditions, including cancer and neurological disorders; however, recently updated studies have indicated that autophagy plays a dual role in cancer, acting as a cytoprotective or cytotoxic mechanism. Numerous preclinical and clinical investigations have shown that inhibiting autophagy enhances an anticancer medicine's effectiveness in various malignancies. Autophagy antagonists, including chloroquine and hydroxychloroquine, have previously been authorized in clinical trials, encouraging the development of medication-combination therapies targeting the autophagic processes for cancer. In this review, we provide an update on the recent research examining the anticancer efficacy of combining drugs that activate cytoprotective autophagy with autophagy inhibitors. Additionally, we highlight the difficulties and progress toward using cytoprotective autophagy targeting as a cancer treatment strategy. Importantly, we must enable the use of suitable autophagy inhibitors and coadministration delivery systems in conjunction with anticancer agents. Therefore, this review briefly summarizes the general molecular process behind autophagy and its bifunctional role that is important in cancer suppression and in encouraging tumor growth and resistance to chemotherapy and metastasis regulation. We then emphasize how autophagy and cancer cells interacting with one another is a promising therapeutic target in cancer treatment.

The Emerging Role of Autophagy as a Target of Environmental Pollutants: An Update on Mechanisms

Autophagy is an evolutionarily conserved cellular system crucial for cellular homeostasis that protects cells from a broad range of internal and extracellular stresses. Autophagy decreases metabolic load and toxicity by removing damaged cellular components. Environmental contaminants, particularly industrial substances, can influence autophagic flux by enhancing it as a protective response, preventing it, or converting its protective function into a pro-cell death mechanism. Environmental toxic materials are also notorious for their tendency to bioaccumulate and induce pathophysiological vulnerability. Many environmental pollutants have been found to influence stress which increases autophagy. Increasing autophagy was recently shown to improve stress resistance and reduce genetic damage. Moreover, suppressing autophagy or depleting its resources either increases or decreases toxicity, depending on the circumstances. The essential process of selective autophagy is utilized by mammalian cells in order to eliminate particulate matter, nanoparticles, toxic metals, and smoke exposure without inflicting damage on cytosolic components. Moreover, cigarette smoke and aging are the chief causes of chronic obstructive pulmonary disease (COPD)-emphysema; however, the disease's molecular mechanism is poorly known. Therefore, understanding the impacts of environmental exposure via autophagy offers new approaches for risk assessment, protection, and preventative actions which will counter the harmful effects of environmental contaminants on human and animal health.

Lysosomes as a Target of Anticancer Therapy

Lysosomes are organelles containing acidic hydrolases that are responsible for lysosomal degradation and the maintenance of cellular homeostasis. They play an important role in autophagy, as well as in various cell death pathways, such as lysosomal and apoptotic death. Various agents, including drugs, can induce lysosomal membrane permeability, resulting in the translocation of acidic hydrolases into the cytoplasm, which promotes lysosomal-mediated death. This type of death may be of great importance in anti-cancer therapy, as both cancer cells with disturbed pathways leading to apoptosis and drug-resistant cells can undergo it. Important compounds that damage the lysosomal membrane include lysosomotropic compounds, antihistamines, immunosuppressants, DNA-damaging drugs, chemotherapeutics, photosensitizers and various plant compounds. An interesting approach in the treatment of cancer and the search for ways to overcome the chemoresistance of cancer cells may also be combining lysosomotropic compounds with targeted modulators of autophagy to induce cell death. These compounds may be an alternative in oncological treatment, and lysosomes may become a promising therapeutic target for many diseases, including cancer. Understanding the functional relationships between autophagy and apoptosis and the possibilities of their regulation, both in relation to normal and cancer cells, can be used to develop new and more effective anticancer therapies.

Pharmacological Activities of Ginkgolic Acids in Relation to Autophagy

Plant-derived natural compounds are widely used as alternative medicine in healthcare throughout the world. Ginkgolic acids, the phenolic compounds isolated from the leaves and seeds of Ginkgo biloba, are among the chemicals that have been explored the most. Ginkgolic acids exhibit cytotoxic activity against a vast number of human cancers in various preclinical models in vitro and in vivo. Additionally, the pharmacological activities of ginkgolic acids are also involved in antidiabetic, anti-bacteria, anti-virus, anti-fibrosis, and reno/neuroprotection. Autophagy as a highly conserved self-cleaning process that plays a crucial role in maintaining cellular and tissue homeostasis and has been proven to serve as a protective mechanism in the pathogenesis of many diseases, including neurodegenerative diseases, cancer, and infectious diseases. In this review, we surveyed the pharmacological activities of the major three forms of ginkgolic acids (C13:0, C15:1, and C17:1) that are linked to autophagic activity and the mechanisms to which these compounds may participate. A growing body of studies in last decade suggests that ginkgolic acids may represent promising chemical compounds in future drug development and an alternative remedy in humans.

Focusing on the Role of Natural Products in Overcoming Cancer Drug Resistance: An Autophagy-Based Perspective

Autophagy is a critical cellular adaptive response in tumor formation. Nutritional deficiency and hypoxia exacerbate autophagic flux in established malignancies, promoting tumor cell proliferation, migration, metastasis, and resistance to therapeutic interventions. Pro-survival autophagy inhibition may be a promising treatment option for advanced cancer. Furthermore, excessive or persistent autophagy is cytotoxic, resulting in tumor cell death. Targeted autophagy activation has also shown significant promise in the fight against tumor drug resistance. Several research groups have examined the ability of natural products (NPs) such as alkaloids, terpenoids, polyphenols, and anthraquinones to serve as autophagy inhibitors or activators. The data support the capacity of NPs that promote lethal autophagy or inhibit pro-survival autophagy from being employed against tumor drug resistance. This paper discusses the potential applications of NPs that regulate autophagy in the fight against tumor drug resistance, some limitations of the current studies, and future research needs and priorities.