The dual role of autophagy in cancer

Inhibition of MSH6 augments the antineoplastic efficacy of cisplatin in non-small cell lung cancer as autophagy modulator

The altered response to chemotherapeutic agents predominantly stems from heightened single-point mutations within coding regions and dysregulated expression levels of genes implicated in drug resistance mechanisms. The identification of biomarkers based on mutation profiles and expression levels is pivotal for elucidating the underlying mechanisms of altered drug responses and for refining combinatorial therapeutic strategies in the field of oncology. Utilizing comprehensive bioinformatic analyses, we investigated the impact of eight mismatch repair (MMR) genes on overall survival across 23 cancer types, encompassing more than 7500 tumors, by integrating their mutation profiles. Among these genes, MSH6 emerged as the most predictive biomarker, characterized by a pronounced mutation frequency and elevated expression levels, which correlated with poorer patient survival outcomes. The wet lab experiments disclosed the impact of MSH6 in mediating altered drug responses. Cytotoxic assays conducted revealed that the depletion of MSH6 in H460 non-small lung cancer cells augmented the efficacy of cisplatin, carboplatin, and gemcitabine. Pathway analyses further delineated the involvement of MSH6 as a modulator, influencing the delicate equilibrium between the pro-survival and pro-death functions of autophagy. Our study elucidates the intricate interplay between MSH6, autophagy, and cisplatin efficacy, highlighting MSH6 as a potential therapeutic target to overcome cisplatin resistance. By revealing the modulation of autophagy pathways by MSH6 inhibition, our findings offer insights into novel approaches for enhancing the efficacy of cisplatin-based cancer therapy through targeted interventions.

Crizotinib Enhances PARP Inhibitor Efficacy in Ovarian Cancer Cells and Xenograft Models by Inducing Autophagy

Poly (ADP-ribose) polymerase inhibitors (PARPi) can encounter resistance through various mechanisms, limiting their effectiveness. Our recent research showed that PARPi alone can induce drug resistance by promoting autophagy. Moreover, our studies have revealed that anaplastic lymphoma kinase (ALK) plays a role in regulating the survival of ovarian cancer cells undergoing autophagy. Here, we explored whether the ALK-inhibitor crizotinib could enhance the efficacy of PARPi by targeting drug-induced autophagic ovarian cancer cell and xenograft models. Our investigation demonstrates that crizotinib enhances the anti-tumor activity of PARPi across multiple ovarian cancer cells. Combination therapy with crizotinib and olaparib reduced cell viability and clonogenic growth in two-olaparib resistant cell lines. More importantly, this effect was consistently observed in patient-derived organoids. Furthermore, combined treatment with crizotinib and olaparib led to tumor regression in human ovarian xenograft models. Mechanistically, the combination resulted in increased levels of reactive oxygen species (ROS), induced DNA damage, and decreased the phosphorylation of AKT, mTOR, and ULK-1, contributing to increased olaparib-induced autophagy and apoptosis. Notably, pharmacologic, or genetic inhibition or autophagy reduced the sensitivity of ovarian cancer cell lines to olaparib and crizotinib treatment, underscoring the role of autophagy in cell death. Blocking ROS mitigated olaparib/crizotinib-induced autophagy and cell death while restoring levels of phosphorylated AKT, mTOR and ULK-1. These findings suggest that crizotinib can improve the therapeutic efficacy of olaparib by enhancing autophagy. Implications: The combination of crizotinib and PARPi presents a promising strategy, that could provide a novel approach to enhance outcomes for patients with ovarian cancer.

Autophagy in aging-related diseases and cancer: Principles, regulatory mechanisms and therapeutic potential

Macroautophagy/autophagy is primarily accountable for the degradation of damaged organelles and toxic macromolecules in the cells. Regarding the essential function of autophagy for preserving cellular homeostasis, changes in, or dysfunction of, autophagy flux can lead to disease development. In the current paper, the complicated function of autophagy in aging-associated pathologies and cancer is evaluated, highlighting the underlying molecular mechanisms that can affect longevity and disease pathogenesis. As a natural biological process, a reduction in autophagy is observed with aging, resulting in an accumulation of cell damage and the development of different diseases, including neurological disorders, cardiovascular diseases, and cancer. The MTOR, AMPK, and ATG proteins demonstrate changes during aging, and they are promising therapeutic targets. Insulin/IGF1, TOR, PKA, AKT/PKB, caloric restriction and mitochondrial respiration are vital for lifespan regulation and can modulate or have an interaction with autophagy. The specific types of autophagy, such as mitophagy that degrades mitochondria, can regulate aging by affecting these organelles and eliminating those mitochondria with genomic mutations. Autophagy and its specific types contribute to the regulation of carcinogenesis and they are able to dually enhance or decrease cancer progression. Cancer hallmarks, including proliferation, metastasis, therapy resistance and immune reactions, are tightly regulated by autophagy, supporting the conclusion that autophagy is a promising target in cancer therapy.

Last but not least: emerging roles of the autophagy-related protein ATG4D

The evolutionarily conserved ATG4 cysteine proteases regulate macroautophagy/autophagy through the priming and deconjugation of the Atg8-family proteins. In mammals there are four ATG4 family members (ATG4A, ATG4B, ATG4C, ATG4D) but ATG4D has been relatively understudied. Heightened interest in ATG4D has been stimulated by recent links to human disease. Notably, genetic variations in human ATG4D were implicated in a heritable neurodevelopmental disorder. Genetic analyses in dogs, along with loss-of-function zebrafish and mouse models, further support a neuroprotective role for ATG4D. Here we discuss the evidence connecting ATG4D to neurological diseases and other pathologies and summarize its roles in both autophagy-dependent and autophagy-independent cellular processes.Abbrevation: ATG: autophagy related; BafA1: bafilomycin A1; BCL2: BCL2 apoptosis regulator; BH3: BCL2 homology region 3; CASP3: caspase 3; EV: extracellular vesicle; GABA: gamma aminobutyric acid; GABARAP: GABA type A receptor-associated protein; GABARAPL1: GABA type A receptor associated protein like 1; GABARAPL2: GABA type A receptor associated protein like 2; GFP: green fluorescent protein; LIR: LC3-interacting region; MAP1LC3: microtubule associated protein 1 light chain 3; MEF: mouse embryonic fibroblast; MYC: MYC proto-oncogene, bHLH transcription factor; PE: phosphatidylethanolamine; PS: phosphatidylserine; QKO: quadruple knockout; SDS-PAGE: sodium dodecyl sulfate-polyacrylamide gel; SQSTM1: sequestosome 1.

Immunohistochemical Profile of p62/SQSTM1/Sequestosome-1 in Human Low- and High-Grade Intracranial Meningiomas

Among autophagic-related proteins, p62/SQSTM1/Sequestosome-1 represents a relevant actor in cellular proliferation and neoplastic growth. Although, recently, p62 expression has been analyzed in different neurodegenerative and glial neoplastic diseases, no available information have been reported in meningiomas, which have an high epidemiological relevance being the second most common category of intracranial tumors after gliomas. Generally meningiomas have a benign behavior, but their recurrence is not uncommon mainly when atypical or anaplastic varieties occur. However, intranuclear vacuoles have been ultrastructurally observed in meningiomas, and they were labelled by p62 antibodies. Therefore, in the present study, we have investigated p62 immunohistochemical pattern in a cohort of 133 cases representative of low- and high-grade meningiomas, to verify if p62 expression may be related to clinicopathological data, thus achieving a potential prognostic role. The p62 immunoexpression was frequently found in the nucleus and cytoplasm of neoplastic elements, and utilizing an intensity-distribution score, 55 (41.3%) cases were considered as high expressors while 78 (58.7%) cases were instead recorded as low expressors. Fifteen cases exhibited recurrences of the disease, 14 of which were codified as high expressors. Moreover, a direct relationship between p62 and Mib-1 immunoexpression as well as between p62 and neoplastic grade have been documented. Finally, we suggest that impaired autophagic flux with an increase in p62 expression may be involved in the activation of NRF2 also contributing in the development of recurrence in meningioma patients.

Atorvastatin causes developmental and behavioral toxicity in yellowstripe goby (Mugilogobius chulae) embryos/larvae via disrupting lipid metabolism and autophagy processes

Atorvastatin (ATV) is one of the most commonly prescribed lipid-lowering drugs detected frequently in the environment due to its high use and low degradation rate. However, the toxic effects of residual ATV in the aquatic environment on non-target organisms and its toxic mechanisms are still largely unknown. In the present study, embryos of a native estuarine benthic fish, Mugilogobius chulae, were employed to investigate the developmental and behavioral toxic effects of ATV including environmentally relevant concentrations. The aim of this study was to provide a scientific basis for ecological risk assessment of ATV in the aquatic environment by investigating the changes of biological endpoints at multiple levels in M. chulae embryos/larvae. The results showed that ATV had significantly lethal and teratogenic effects on M. chulae embryos/larvae and caused abnormal changes in developmental parameters including hatch rate, body length, heart rate, and spontaneous movement. ATV exposure caused oxidative stress in M. chulae embryos/larvae subsequently inhibited autophagy and activated apoptosis, leading to abnormal developmental processes and behavioral changes in M. chulae embryos/larvae. The disruptions of lipid metabolism, autophagy, and apoptosis in M. chulae embryos/larvae caused by ATV exposure may pose a potential ecological risk at the population level.

Dysregulation of autophagy in gastric carcinoma: Pathways to tumor progression and resistance to therapy

The considerable death rates and lack of symptoms in early stages of gastric cancer (GC) make it a major health problem worldwide. One of the most prominent risk factors is infection with Helicobacter pylori. Many biological processes, including those linked with cell death, are disrupted in GC. The cellular "self-digestion" mechanism necessary for regular balance maintenance, autophagy, is at the center of this disturbance. Misregulation of autophagy, however, plays a role in the development of GC. In this review, we will examine how autophagy interacts with other cell death processes, such as apoptosis and ferroptosis, and how it affects the progression of GC. In addition to wonderful its role in the epithelial-mesenchymal transition, it is engaged in GC metastasis. The role of autophagy in GC in promoting drug resistance stands out. There is growing interest in modulating autophagy for GC treatment, with research focusing on natural compounds, small-molecule inhibitors, and nanoparticles. These approaches could lead to breakthroughs in GC therapy, offering new hope in the fight against this challenging disease.

Autophagy in cancer immunotherapy: Perspective on immune evasion and cell death interactions

Both the innate and adaptive immune systems work together to produce immunity. Cancer immunotherapy is a novel approach to tumor suppression that has arisen in response to the ineffectiveness of traditional treatments like radiation and chemotherapy. On the other hand, immune evasion can diminish immunotherapy's efficacy. There has been a lot of focus in recent years on autophagy and other underlying mechanisms that impact the possibility of cancer immunotherapy. The primary feature of autophagy is the synthesis of autophagosomes, which engulf cytoplasmic components and destroy them by lysosomal degradation. The planned cell death mechanism known as autophagy can have opposite effects on carcinogenesis, either increasing or decreasing it. It is autophagy's job to maintain the balance and proper functioning of immune cells like B cells, T cells, and others. In addition, autophagy controls whether macrophages adopt the immunomodulatory M1 or M2 phenotype. The ability of autophagy to control the innate and adaptive immune systems is noteworthy. Interleukins and chemokines are immunological checkpoint chemicals that autophagy regulates. Reducing antigen presentation to induce immunological tolerance is another mechanism by which autophagy promotes cancer survival. Therefore, targeting autophagy is of importance for enhancing potential of cancer immunotherapy.

The role of programmed cell death in osteosarcoma: From pathogenesis to therapy

Osteosarcoma (OS) is a prevalent bone solid malignancy that primarily affects adolescents, particularly boys aged 14-19. This aggressive form of cancer often leads to deadly lung cancer due to its high migration ability. Experimental evidence suggests that programmed cell death (PCD) plays a crucial role in the development of osteosarcoma. Various forms of PCD, including apoptosis, ferroptosis, autophagy, necroptosis, and pyroptosis, contribute significantly to the progression of osteosarcoma. Additionally, different signaling pathways such as STAT3/c-Myc signal pathway, JNK signl pathway, PI3k/AKT/mTOR signal pathway, WNT/β-catenin signal pathway, and RhoA signal pathway can influence the development of osteosarcoma by regulating PCD in osteosarcoma cell. Therefore, targeting PCD and the associated signaling pathways could offer a promising therapeutic approach for treating osteosarcoma.

Response of lipid metabolism, energy supply, and cell fate in yellowstripe goby (Mugilogobius chulae) exposed to environmentally relevant concentrations atorvastatin

The usage of typical pharmaceuticals and personal care products (PPCPs) such as cardiovascular and lipid-modulating drugs in clinical care accounts for the largest share of pharmaceutical consumption in most countries. Atorvastatin (ATV), one of the most commonly used lipid-lowering drugs, is frequently detected with lower concentrations in aquatic environments owing to its wide application, low removal, and degradation rates. However, the adverse effects of ATV on non-target aquatic organisms, especially the molecular mechanisms behind the toxic effects, still remain unclear. Therefore, this study investigated the potentially toxic effects of ATV exposure (including environmental concentrations) on yellowstripe goby (Mugilogobius chulae) and addressed the multi-dimensional responses. The results showed that ATV caused typical hepatotoxicity to M. chulae. ATV interfered with lipid metabolism by blocking fatty acid β-oxidation and led to the over-consumption of lipids. Thus, the exposed organism was obliged to alter the energy supply patterns and substrates utilization pathways to keep the normal energy supply. In addition, the higher concentration of ATV exposure caused oxidative stress to the organism. Subsequently, M. chulae triggered the autophagy and apoptosis processes with the help of key stress-related transcriptional regulators FOXOs and Sestrins to degrade the damaged organelles and proteins to maintain intracellular homeostasis.

Dual targeting agent Thiotert inhibits the progression of glioblastoma by inducing ER stress-dependent autophagy

Glioblastoma (GBM) is the most aggressive and lethal type of tumor in the central nervous system, characterized by a high incidence and poor prognosis. Thiotert, as a novel dual targeting agent, has potential inhibitory effects on various tumors. Here, we found that Thiotert effectively inhibited the proliferation of GBM cells by inducing G2/M cell cycle arrest and suppressed the migratory ability in vitro. Furthermore, Thiotert disrupted the thioredoxin (Trx) system while causing cellular DNA damage, which in turn caused endoplasmic reticulum (ER) stress-dependent autophagy. Knockdown of ER stress-related protein ATF4 in U251 cells inhibited ER stress-dependent autophagy caused by Thiotert to some extent. Orthotopic transplantation experiments further showed that Thiotert had the same anti-GBM activity and mechanism as in vitro. Conclusively, these results suggest that Thiotert induces ER stress-dependent autophagy in GBM cells by disrupting redox homeostasis and causing DNA damage, which provides new insight for the treatment of GBM.

The route of autophagy regulation by osteopontin: a review on the linking mechanisms

Autophagy is a dynamic intracellular process of protein degradation, which is mostly triggered by nutrient deprivation. This process initiates with the formation of autophagosomes, which they capture cytosolic material that is then degraded upon fusion with the lysosome. Several factors have been found to be associated with autophagy modulation, of which extracellular matrix (ECM) components has attracted the attention of recent studies. Osteopontin (OPN) is an important extracellular matrix component that has been detected in a wide range of tumor cells, and is involved in cancer cell invasion and metastasis. Recently, a number of studies have focused on the relationship of OPN with autophagy, by delineating the intracellular signaling pathways that connect OPN to the autophagy process. We will summarize signaling pathways and cell surface receptors, through which OPN regulates the process of autophagy.

TRPM2: bridging calcium and ROS signaling pathways-implications for human diseases

TRPM2 is a versatile and essential signaling molecule that plays diverse roles in Ca2+ homeostasis and oxidative stress signaling, with implications in various diseases. Research evidence has shown that TRPM2 is a promising therapeutic target. However, the decision of whether to activate or inhibit TRPM2 function depends on the context and specific disease. A deeper understanding of the molecular mechanisms governing TRPM2 activation and regulation could pave the way for the development of innovative therapeutics targeting TRPM2 to treat a broad range of diseases. In this review, we examine the structural and biophysical details of TRPM2, its involvement in neurological and cardiovascular diseases, and its role in inflammation and immune system function. In addition, we provide a comprehensive overview of the current knowledge of TRPM2 signaling pathways in cancer, including its functions in bioenergetics, oxidant defense, autophagy, and response to anticancer drugs.

Functional impact of non-coding RNAs in high-grade breast carcinoma: Moving from resistance to clinical applications: A comprehensive review

Despite the recent advances in cancer therapy, triple-negative breast cancers (TNBCs) are the most relapsing cancer sub-type. It is partly due to their propensity to develop resistance against the available therapies. An intricate network of regulatory molecules in cellular mechanisms leads to the development of resistance in tumors. Non-coding RNAs (ncRNAs) have gained widespread attention as critical regulators of cancer hallmarks. Existing research suggests that aberrant expression of ncRNAs modulates the oncogenic or tumor suppressive signaling. This can mitigate the responsiveness of efficacious anti-tumor interventions. This review presents a systematic overview of biogenesis and down streaming molecular mechanism of the subgroups of ncRNAs. Furthermore, it explains ncRNA-based strategies and challenges to target the chemo-, radio-, and immunoresistance in TNBCs from a clinical standpoint.

Therapeutic Properties of Flavonoids in Treatment of Cancer through Autophagic Modulation: A Systematic Review

Cancers have high morbidity and mortality rates worldwide. Current anticancer therapies have demonstrated specific signaling pathways as a target in the involvement of carcinogenesis. Autophagy is a quality control system for proteins and plays a fundamental role in cancer carcinogenesis, exerting an anticarcinogenic role in normal cells and can inhibit the transformation of malignant cells. Therefore, drugs aimed at autophagy can function as antitumor agents. Flavonoids are a class of polyphenolic secondary metabolites commonly found in plants and, consequently, consumed in diets. In this review, the systematic search strategy was used, which included the search for descriptors "flavonoids" AND "mTOR pathway" AND "cancer" AND "autophagy", in the electronic databases of PubMed, Cochrane Library, Web of Science and Scopus, from January 2011 to January 2021. The current literature demonstrates that flavonoids have anticarcinogenic properties, including inhibition of cell proliferation, induction of apoptosis, autophagy, necrosis, cell cycle arrest, senescence, impaired cell migration, invasion, tumor angiogenesis and reduced resistance to multiple drugs in tumor cells. We demonstrate the available evidence on the roles of flavonoids and autophagy in cancer progression and inhibition. (Registration No. CRD42021243071 at PROSPERO).

Xanthatin suppresses proliferation and tumorigenicity of glioma cells through autophagy inhibition via activation of the PI3K-Akt-mTOR pathway

Glioma is the most common and aggressive primary brain tumor in adults with high morbidity and mortality. Rapid proliferation and diffuse migration are the main obstacles to successful glioma treatment. Xanthatin, a sesquiterpene lactone purified from Xanthium strumarium L., possesses a significant antitumor role in several malignant tumors. In this study, we report that xanthatin suppressed glioma cells proliferation and induced apoptosis in a time- and concentration-dependent manner, and was accompanied by autophagy inhibition displaying a significantly reduced LC3 punctate fluorescence and LC3II/I ratio, decreased level of Beclin 1, while increased accumulation of p62. Notably, treating glioma cells with xanthatin resulted in obvious activation of the PI3K-Akt-mTOR signaling pathway, as indicated by increased mTOR and Akt phosphorylation, decreased ULK1 phosphorylation, which is important in modulating autophagy. Furthermore, xanthatin-mediated pro-apoptosis in glioma cells was significantly reversed by autophagy inducers (rapamycin or Torin1), or PI3K-mTOR inhibitor NVP-BEZ235. Taken together, these findings indicate that anti-proliferation and pro-apoptosis effects of xanthatin in glioma are most likely by inhibiting autophagy via activation of PI3K-Akt-mTOR pathway, suggesting a potential therapeutic strategy against glioma.

Anti-cancer effect of in vivo inhibition of nitric oxide synthase in a rat model of breast cancer

Increased expression of nitric oxide synthase (NOS) is associated with different cancers such as cervical, breast, lung, brain, and spinal cord. Inhibition of NOS activity has been suggested as potential tool to prevent breast cancer. The anti-tumor therapeutic effect of L-nitro arginine methyl ester (L-NAME), NOS inhibitor, using in vivo models is currently under investigation. We hypothesized that L-NAME will show an anti-tumor effect by delaying a progression of breast cancer via a modulation of cell death and proliferation, and angiogenesis. We used a novel model of anti-cancer treatment by the administration of L-NAME (30 mg/kg in a day, intraperitoneal) injected every third day for five weeks to rat model of 7,12-dimethylbenz[a]anthracene (DMBA)-induced breast tumor. Concentrations of nitrite anions, polyamines, malondialdehyde, NH₄⁺ levels, and arginase activity in the blood were decreased in DMBA + L-NAME-treated rats compared with DMBA rats. The mortality rates, tumor number, weight, and volume, as well as the histopathological grade of breast cancer were also significantly reduced. In addition, L-NAME treatment showed a delay in tumor formation, and in body weight compared with rats administrated only with DMBA. In conclusion, our data show that L-NAME is a promising anti-cancer agent to treat breast cancer, which can lead to development of anti-tumor therapeutic tools in future.

Cannabidiol regulates apoptosis and autophagy in inflammation and cancer: A review

Cannabidiol (CBD) is a terpenoid naturally found in plants. The purified compound is used in the treatment of mental disorders because of its antidepressive, anxiolytic, and antiepileptic effects. CBD can affect the regulation of several pathophysiologic processes, including autophagy, cytokine secretion, apoptosis, and innate and adaptive immune responses. However, several authors have reported contradictory findings concerning the magnitude and direction of CBD-mediated effects. For example, CBD treatment can increase, decrease, or have no significant effect on autophagy and apoptosis. These variable results can be attributed to the differences in the biological models, cell types, and CBD concentration used in these studies. This review focuses on the mechanism of regulation of autophagy and apoptosis in inflammatory response and cancer by CBD. Further, we broadly elaborated on the prospects of using CBD as an anti-inflammatory agent and in cancer therapy in the future.

Enhancing Anti-Cancer Therapy with Selective Autophagy Inhibitors by Targeting Protective Autophagy

Autophagy is a process of eliminating damaged or unnecessary proteins and organelles, thereby maintaining intracellular homeostasis. Deregulation of autophagy is associated with several diseases including cancer. Contradictory dual roles of autophagy have been well established in cancer. Cytoprotective mechanism of autophagy has been extensively investigated for overcoming resistance to cancer therapies including radiotherapy, targeted therapy, immunotherapy, and chemotherapy. Selective autophagy inhibitors that directly target autophagic process have been developed for cancer treatment. Efficacies of autophagy inhibitors have been tested in various pre-clinical cancer animal models. Combination therapies of autophagy inhibitors with chemotherapeutics are being evaluated in clinal trials. In this review, we will focus on genetical and pharmacological perturbations of autophagy-related proteins in different steps of autophagic process and their therapeutic benefits. We will also summarize combination therapies of autophagy inhibitors with chemotherapies and their outcomes in pre-clinical and clinical studies. Understanding of current knowledge of development, progress, and application of cytoprotective autophagy inhibitors in combination therapies will open new possibilities for overcoming drug resistance and improving clinical outcomes.

Establishment and validation of individualized clinical prognostic markers for LUAD patients based on autophagy-related genes

There is considerable heterogeneity in the genomic drivers of lung adenocarcinoma, which has a dismal prognosis. Bioinformatics analysis was performed on lung adenocarcinoma (LUAD) datasets to establish a multi-autophagy gene model to predict patient prognosis. LUAD data were downloaded from The Cancer Genome Atlas (TCGA) database as a training set to construct a LUAD prognostic model. According to the risk score, a Kaplan-Meier cumulative curve was plotted to evaluate the prognostic value. Furthermore, a nomogram was established to predict the three-year and five-year survival of patients with LUAD based on their prognostic characteristics. Two genes (ITGB1 and EIF2AK3) were identified in the autophagy-related prognostic model, and the multivariate Cox proportional risk model showed that risk score was an independent predictor of prognosis in LUAD patients (HR=3.3, 95%CI= 2.3 to 4.6, P< 0.0001). The Kaplan-Meier cumulative curve showed that low-risk patients had significantly better overall (P<0.0001). The validation dataset GSE68465 further confirmed the nomogram’s robust ability to assess the prognosis of LUAD patients. A prognosis model of autophagy-related genes based on a LUAD dataset was constructed and exhibited diagnostic value in the prognosis of LUAD patients. Moreover, real-time qPCR confirmed the expression patterns of EIF2AK3 and ITGB1 in LUAD cell lines. Two key autophagy-related genes have been suggested as prognostic markers for lung adenocarcinoma.

U0126: Not only a MAPK kinase inhibitor

U0126, as an inhibitor of the MAPK signaling pathway, is closely related to various biological processes, such as differentiation, cell growth, autophagy, apoptosis, and stress responses. It makes U0126 play an essential role in balancing cellular homeostasis. Although U0126 has been suggested to inhibit various cancers, its complete mechanisms have not been clarified in cancers. This review summarized the most recent and relevant research on the many applications of U0126 and described its role and mechanisms in different cancer cell types. Moreover, some acknowledged functions of U0126 researched in the laboratory were listed in our review. We discussed the probability of using U0126 to restain cancers or suppress the MAPK pathway as a novel way of cancer treatment.

Immunoexpression of p62/SQSTM1/Sequestosome‑1 in human primary and recurrent IDH1/2 wild‑type glioblastoma: A pilot study

p62/SQSTM1/Sequestosome-1 is an autophagic protein that serves a crucial role in cellular metabolism, proliferation and malignant growth. Notably, autophagy may influence the development and resistance to therapy of numerous types of human cancer. In the present pilot study, the immunohistochemical pattern of p62 was analyzed in a cohort of patients with isocitrate dehydrogenase (IDH)1/2 wild-type glioblastoma (GBM), in primary and recurrent samples, in order to verify the concordance or discordance between the primary and recurrent tumors. In addition, the association between p62, and patient outcome and O⁶-methylguanine-DNA methyltransferase (MGMT) status was assessed. The results revealed p62 immunoexpression in the nucleus and cytoplasm of neoplastic elements in 45% of primary and 55% of recurrent cases of GBM. A discordant p62 immunoreactivity was detected in 35% of cases, with a variation either with positive or negative conversion of p62 status. Statistically, p62 expression and MGMT status exhibited a significant prognostic value by univariate analysis, whereas only MGMT promoter methylation status emerged as an independent prognostic factor by multivariate analysis. Finally, the most favorable prognosis was documented when the same GBM case was positively concordant for both p62 expression and MGMT methylated status. Since little data are available regarding the association between p62 expression and MGMT in GBM, further investigations may be required to determine if new targeted therapies may be addressed against autophagy-related proteins, such as p62.

In Vitro Anticancer Activity of Two Ferrocene-Containing Camphor Sulfonamides as Promising Agents against Lung Cancer Cells

The successful design of antitumour drugs often combines in one molecule different biologically active subunits that can affect various regulatory pathways in the cell and thus achieve higher efficacy. Two ferrocene derivatives, DK-164 and CC-78, with different residues were tested for cytotoxic potential on non-small lung cancer cell lines, A549 and H1299, and non-cancerous MRC5. DK-164 demonstrated remarkable selectivity toward cancer cells and more pronounced cytotoxicity against A549. The cytotoxicity of CC-78 toward H1299 was even higher than that of the well-established anticancer drugs cisplatin and tamoxifen, but it did not reveal any noticeable selective effect. DK-164 showed predominantly pro-apoptotic activity in non-small cell lung carcinoma (NSCLC) cells, while CC-78 caused accidental cell death with features characteristic of necrosis. The level of induced autophagy was similar for both substances in cancer cells. DK-164 treatment of A549, H1299, and MRC5 cells for 48 h significantly increased the fluorescence signal of the NFkB (nuclear factor ‘kappa-light-chain-enhancer’ of activated B-cells) protein in the nucleus in all three cell lines, while CC-78 did not provoke NFkB translocation in any of the tested cell lines. Both compounds caused a significant transfer of the p53 protein in the nucleus of A549 cells but not in non-cancerous MRC5 cells. In A549, DK-164 generated oxidative stress close to the positive control after 48 h, while CC-78 had a moderate effect on the cellular redox status. In the non-cancerous cells, MRC5, both compounds produced ROS similar to the positive control for the same incubation period. The different results related to the cytotoxic potential of DK-164 and CC-78 associated with the examined cellular mechanisms induced in lung cancer cells might be used to conclude the specific functions of the various functional groups in the ferrocene compounds, which can offer new perspectives for the design of antitumour drugs.

TRIM22 inhibits osteosarcoma progression through destabilizing NRF2 and thus activation of ROS/AMPK/mTOR/autophagy signaling

Osteosarcoma (OS) is a malignant bone tumor that mainly occurs in adolescents. It is accompanied by a high rate of lung metastasis, and high mortality. Recent studies have suggested the important roles of tripartite motif-containing (TRIM) family proteins in regulating various substrates and signaling pathways in different tumors. However, the detailed functional role of TRIM family proteins in the progression of OS is still unknown and requires further investigations. In this study, we found that tripartite motif-containing 22 (TRIM22) was downregulated in OS tissues and was hence associated with better prognosis. In vitro and in vivo functional analysis demonstrated that TRIM22 inhibits proliferation and metastasis of OS cells. Nuclear factor erythroid 2-related factor 2 (NRF2), a redox regulator, was identified as a novel target for TRIM22. TRIM22 interacts with and accelerates the degradation of NRF2 by inducing its ubiquitination dependent on its E3 ligase activity but independent of Kelch-like ECH-associated protein 1 (KEAP1). Further, a series of gain- and loss-of-function experiments showed that knockdown or overexpression of NRF2 reversed the functions of knockdown or overexpression of TRIM22 in OS. Mechanistically, TRIM22 inhibited OS progression through NRF2-mediated intracellular reactive oxygen species (ROS) imbalance. ROS production was significantly promoted and mitochondrial potential was remarkably inhibited when overexpressing TRIM22, thus activating AMPK/mTOR signaling. Moreover, TRIM22 was also found to inhibit Warburg effect in OS cells. Autophagy activation was found in OS cells which were overexpressed TRIM22, thus leading to autophagic cell death. Treatment with N-Acetylcysteine (NAC), a ROS scavenger or the autophagy inhibitor 3-Methyladenine (3-MA) abolished the decreased malignant phenotypes in TRIM22 overexpressing OS cells. In conclusion, our study indicated that TRIM22 inhibits OS progression by promoting proteasomal degradation of NRF2 independent of KEAP1, thereby activating ROS/AMPK/mTOR/Autophagy signaling that leads to autophagic cell death in OS. Therefore, our findings indicated that targeting TRIM22/NRF2 could be a promising therapeutic target for treating OS.

•

TRIM22 inhibits proliferation and metastasis of OS cells.

•

TRIM22 interacts with and accelerates NRF2 degradation by inducing its ubiquitination dependent on E3 ligase activity.

•

TRIM22 inhibited OS progression through NRF2-mediated intracellular ROS imbalance.

•

TRIM22 inhibits OS progression by promoting NRF2 degradation, thereby activating ROS/AMPK/mTOR/Autophagy signaling.

An Overview of Hepatocellular Carcinoma After Insufficient Radiofrequency Ablation

Radiofrequency ablation (RFA) is a commonly used treatment for hepatocellular carcinoma (HCC), however, various complex conditions in clinical practice may lead to insufficient radiofrequency ablation (IRFA), allowing residual HCC to survive. In clinical practice and laboratory models, IRFA plays an important role in rapid tumor progression. Therefore, targeting the residual HCC and avoiding IRFA were worthwhile methods. A deeper understanding of IRFA is required; IRFA contributes to the improvement of proliferative activity, migration rates, and invasive capacity, and this may be due to the involvement of multiple complex processes or proteins, including epithelial mesenchymal transitions (EMTs), cancer stem cells (CSCs), autophagy, heat shock proteins (HSPs), changes of non-tumor cells and extracellular matrix, altered immune microenvironment, hypoxia-inducible factors (HIFs), growth factors, epigenetic alterations, and metabolic reprogramming. We focus on the processes of the above mechanisms and possible therapeutic approach, with a review of the literature. Additionally, we recapitulated the construction methods of various experimental models of IRFA (in vivo and in vitro).

The role of autophagy and mitophagy in cancers

Autophagy is an important life phenomenon in eukaryotic cells. Its main role is to remove and degrade its damaged organelles and excess biological macromolecules, and use degradation products to provide energy and rebuild the cell structure, playing an important role in maintaining cell homeostasis and cell life activities. Mitophagy is a form of macroautophagy. It has the beneficial effect of eliminating damaged mitochondria, thereby maintaining the integrity of the mitochondrial pool. Autophagy and mitophagy have a dual role in the development of cancer. On one hand, autophagy and mitophagy can maintain the normal physiological function of cells. On the other hand, excessive autophagy and mitophagy can lead to diseases. The present review introduces the mechanisms of autophagy and mitophagy, and the main related proteins, and introduce the correlation with cancers, providing a basis for the treatment of cancers through the understanding of these proteins.

Patient-derived tumor models are attractive tools to repurpose drugs for ovarian cancer treatment: Pre-clinical updates

Despite advances in understanding of ovarian cancer biology, the progress in translation of research findings into new therapies is still slow. It is associated in part with limitations of commonly used cancer models such as cell lines and genetically engineered mouse models that lack proper representation of diversity and complexity of actual human tumors. In addition, the development of de novo anticancer drugs is a lengthy and expensive process. A promising alternative to new drug development is repurposing existing FDA-approved drugs without primary oncological purpose. These approved agents have known pharmacokinetics, pharmacodynamics, and toxicology and could be approved as anticancer drugs quicker and at lower cost. To successfully translate repurposed drugs to clinical application, an intermediate step of pre-clinical animal studies is required. To address challenges associated with reliability of tumor models for pre-clinical studies, there has been an increase in development of patient-derived xenografts (PDXs), which retain key characteristics of the original patient’s tumor, including histologic, biologic, and genetic features. The expansion and utilization of clinically and molecularly annotated PDX models derived from different ovarian cancer subtypes could substantially aid development of new therapies or rapid approval of repurposed drugs to improve treatment options for ovarian cancer patients.

Ubiquitination-Proteasome System (UPS) and Autophagy Two Main Protein Degradation Machineries in Response to Cell Stress

In response to environmental stimuli, cells make a series of adaptive changes to combat the injury, repair the damage, and increase the tolerance to the stress. However, once the damage is too serious to repair, the cells will undergo apoptosis to protect the overall cells through suicidal behavior. Upon external stimulation, some intracellular proteins turn into unfolded or misfolded protein, exposing their hydrophobic regions to form protein aggregation, which may ultimately produce serious damage to the cells. Ubiquitin plays an important role in the degradation of these unnatural proteins by tagging with ubiquitin chains in the ubiquitin-proteasome or autophagy system. If the two processes fail to eliminate the abnormal protein aggregates, the cells will move to apoptosis and death. Dysregulation of ubiquitin-proteasome system (UPS) and autophagy may result in the development of numerous diseases. This review focuses on the molecular mechanisms of UPS and autophagy in clearance of intracellular protein aggregates, and the relationship between dysregulation of ubiquitin network and diseases.

The Role of Macroautophagy and Chaperone-Mediated Autophagy in the Pathogenesis and Management of Hepatocellular Carcinoma

Simple Summary

Hepatocellular carcinoma (HCC) is a major health problem with the second highest mortality among all cancers and a continuous increase worldwide. HCC is highly resistant to available chemotherapeutic agents, leaving patients with no effective therapeutic option and a poor prognosis. Although an increasing number of studies have elucidated the potential role of autophagy underlying HCC, the complete regulation is far from understood. The different forms of autophagy constitute important cell survival mechanisms that could prevent hepatocarcinogenesis by limiting hepatocyte death and the associated hepatitis and fibrosis at early stages of chronic liver diseases. On the other hand, at late stages of hepatocarcinogenesis, they could support the malignant transformation of (pre)neoplastic cells by facilitating their survival.

Abstract

Hepatocarcinogenesis is a long process with a complex pathophysiology. The current therapeutic options for HCC management, during the advanced stage, provide short-term survival ranging from 10–14 months. Autophagy acts as a double-edged sword during this process. Recently, two main autophagic pathways have emerged to play critical roles during hepatic oncogenesis, macroautophagy and chaperone-mediated autophagy. Mounting evidence suggests that upregulation of macroautophagy plays a crucial role during the early stages of carcinogenesis as a tumor suppressor mechanism; however, it has been also implicated in later stages promoting survival of cancer cells. Nonetheless, chaperone-mediated autophagy has been elucidated as a tumor-promoting mechanism contributing to cancer cell survival. Moreover, the autophagy pathway seems to have a complex role during the metastatic stage, while induction of autophagy has been implicated as a potential mechanism of chemoresistance of HCC cells. The present review provides an update on the role of autophagy pathways in the development of HCC and data on how the modulation of the autophagic pathway could contribute to the most effective management of HCC.

The Apoptosis Paradox in Cancer

Cancer growth represents a dysregulated imbalance between cell gain and cell loss, where the rate of proliferating mutant tumour cells exceeds the rate of those that die. Apoptosis, the most renowned form of programmed cell death, operates as a key physiological mechanism that limits cell population expansion, either to maintain tissue homeostasis or to remove potentially harmful cells, such as those that have sustained DNA damage. Paradoxically, high-grade cancers are generally associated with high constitutive levels of apoptosis. In cancer, cell-autonomous apoptosis constitutes a common tumour suppressor mechanism, a property which is exploited in cancer therapy. By contrast, limited apoptosis in the tumour-cell population also has the potential to promote cell survival and resistance to therapy by conditioning the tumour microenvironment (TME)-including phagocytes and viable tumour cells-and engendering pro-oncogenic effects. Notably, the constitutive apoptosis-mediated activation of cells of the innate immune system can help orchestrate a pro-oncogenic TME and may also effect evasion of cancer treatment. Here, we present an overview of the implications of cell death programmes in tumour biology, with particular focus on apoptosis as a process with "double-edged" consequences: on the one hand, being tumour suppressive through deletion of malignant or pre-malignant cells, while, on the other, being tumour progressive through stimulation of reparatory and regenerative responses in the TME.

Emerging Significance of Ginsenosides as Potentially Reversal Agents of Chemoresistance in Cancer Therapy

Chemoresistance has become a prevalent phenomenon in cancer therapy, which alleviates the effect of chemotherapy and makes it difficult to break the bottleneck of the survival rate of tumor patients. Current approaches for reversing chemoresistance are poorly effective and may cause numerous new problems. Therefore, it is urgent to develop novel and efficient drugs derived from natural non-toxic compounds for the reversal of chemoresistance. Researches in vivo and in vitro suggest that ginsenosides are undoubtedly low-toxic and effective options for the reversal of chemoresistance. The underlying mechanism of reversal of chemoresistance is correlated with inhibition of drug transporters, induction of apoptosis, and modulation of the tumor microenvironment(TME), as well as the modulation of signaling pathways, such as nuclear factor erythroid-2 related factor 2 (NRF2)/AKT, lncRNA cancer susceptibility candidate 2(CASC2)/ protein tyrosine phosphatase gene (PTEN), AKT/ sirtuin1(SIRT1), epidermal growth factor receptor (EGFR)/ phosphatidylinositol 3-kinase (PI3K)/AKT, PI3K/AKT/ mammalian target of rapamycin(mTOR) and nuclear factor-κB (NF-κB). Since the effects and the mechanisms of ginsenosides on chemoresistance reversal have not yet been reviewed, this review summarized comprehensively experimental data in vivo and in vitro to elucidate the functional roles of ginsenosides in chemoresistance reversal and shed light on the future research of ginsenosides.

DNA-Unresponsive Platinum(II) Complex Induces ERS-Mediated Mitophagy in Cancer Cells

Mitophagy is a selective autophagic process that degrades dysfunctional mitochondria. Monofunctional platinum(II) complexes are candidates for anticancer drugs with the potential to circumvent the drug resistance and side effects of cisplatin and its analogues, but their mechanism of action is elusive. Complex Mono-Pt kills cancer cells through a mitophagic pathway. The mechanism involves the stimulation of endoplasmic reticulum stress (ERS) and activation of the unfolded protein response. Mono-Pt severely impairs the structure and function of mitochondria, including disruption of morphological integrity, dissipation of membrane potential, elevation of reactive oxygen species, inhibition of mtDNA transcription, and reduction of adenosine triphosphate (ATP), which ultimately leads to mitophagy. Mono-Pt does not react with nuclear DNA but exhibits potent antiproliferative activity against cancer cells, thus breaking the DNA-binding paradigm and classical structure-activity rules for platinum drugs. The ERS-mediated mitophagy provides an alternative mechanism for platinum complexes, which broadens the way for developing new platinum anticancer drugs.

Canonical and Non-canonical TGFβ Signaling Activate Autophagy in an ULK1-Dependent Manner

The mechanism(s) in which transforming growth factor beta 1 (TGFβ) modulates autophagy in cancer remain unclear. Here, we characterized the TGFβ signaling pathways that induce autophagy in non-small cell lung cancer cells, using cells lines stably expressing GFP-LC3-RFP-LC3ΔG constructs that measure autophagic flux. We demonstrated that TGFβ1 increases Unc 51-like kinase 1 (ULK1) protein levels, 5' adenosine monophosphate-activated protein kinase (AMPK)-dependent ULK1 phosphorylation at serine (S) 555 and ULK1 complex formation but decreases mechanistic target of rapamycin (mTOR) activity on ULK1. Further analysis revealed that the canonical Smad4 pathway and the non-canonical TGFβ activated kinase 1/tumor necrosis factor receptor-associated factor 6/P38 mitogen activated protein kinase (TAK1-TRAF6-P38 MAPK) pathway are important for TGFβ1-induced autophagy. The TAK1-TRAF6-P38 MAPK pathway was essential for downregulating mTOR S2448 phosphorylation, ULK1 S555 phosphorylation and autophagosome formation. Furthermore, although siRNA-mediated Smad4 silencing did not alter mTOR-dependent ULK1 S757 phosphorylation, it did reduce AMPK-dependent ULK1 S555 phosphorylation and autophagosome formation. Additionally, Smad4 silencing and inhibiting the TAK1-TRAF6-P38 MAPK pathway decreased autophagosome-lysosome co-localization in the presence of TGFβ. Our results suggest that the Smad4 and TAK1-TRAF6-P38 MAPK signaling pathways are essential for TGFβ-induced autophagy and provide specific targets for the inhibition of TGFβ in tumor cells that utilize autophagy in their epithelial-mesenchymal transition program.

Optimization of BCG Therapy Targeting Neutrophil Extracellular Traps, Autophagy, and miRNAs in Bladder Cancer: Implications for Personalized Medicine

Bladder cancer (BC) is the ninth most common cancer and the thirteenth most common cause of mortality worldwide. Bacillus Calmette Guerin (BCG) instillation is a common treatment option for BC. BCG therapy is associated with the less adversary effects, compared to chemotherapy, radiotherapy, and other conventional treatments. BCG could inhibit the progression and recurrence of BC by triggering apoptosis pathways, arrest cell cycle, autophagy, and neutrophil extracellular traps (NETs) formation. However, BCG therapy is not efficient for metastatic cancer. NETs and autophagy were induced by BCG and help to suppress the growth of tumor cells especially in the primary stages of BC. Activated neutrophils can stimulate autophagy pathway and release NETs in the presence of microbial pathogenesis, inflammatory agents, and tumor cells. Autophagy can also regulate NETs formation and induce production of reactive oxygen species (ROS) and NETs. Moreover, miRNAs are important regulator of gene expression. These small non-coding RNAs are also considered as an essential factor to control the levels of tumor development. However, the interaction between BCG and miRNAs has not been well-understood yet. Therefore, the present study discusses the roles of miRNAs in regulations of autophagy and NETs formation in BCG therapy in the treatment of BC. The roles of autophagy and NETs formation in BC treatment and efficiency of BCG are also discussed.

Molecular mechanisms of mammalian autophagy

The ubiquitin-proteasome pathway (UPP) and autophagy play integral roles in cellular homeostasis. As part of their normal life cycle, most proteins undergo ubiquitination for some form of redistribution, localization and/or functional modulation. However, ubiquitination is also important to the UPP and several autophagic processes. The UPP is initiated after specific lysine residues of short-lived, damaged or misfolded proteins are conjugated to ubiquitin, which targets these proteins to proteasomes. Autophagy is the endosomal/lysosomal-dependent degradation of organelles, invading microbes, zymogen granules and macromolecules such as protein, carbohydrates and lipids. Autophagy can be broadly separated into three distinct subtypes termed microautophagy, chaperone-mediated autophagy and macroautophagy. Although autophagy was once thought of as non-selective bulk degradation, advancements in the field have led to the discovery of several selective forms of autophagy. Here, we focus on the mechanisms of primary and selective mammalian autophagy pathways and highlight the current knowledge gaps in these molecular pathways.

XPA serves as an autophagy and apoptosis inducer by suppressing hepatocellular carcinoma in a PI3K/Akt/mTOR dependent manner

Background

To explore the potential biological function of XPA (Xeroderma pigmentosum group A) in hepatic neoplasms and the underlying molecular mechanisms.

Methods

Liver cells were used as experimental models to establish HCC (hepatocellular carcinoma) in vitro. Protein extractions were subjected to Western blotting to detect the proteins expression. The lentivirus transfection efficiency was confirmed by Western blot and RT-qPCR, Tunnel staining was used to detect apoptosis, and Transwell assays were used to observe cell migration and invasion. Cell proliferation was detected with colony formation and CCK-8 (cell counting kit-8) assays.

Results

XPA expression was obviously lower in HCC tissue and liver cancer cell lines. XPA overexpression induced autophagy and apoptosis by increasing LC3B II/I, Beclin1, cleaved-caspase-3, and Bax expression and decreasing p62 and Bcl2 protein levels. XPA also suppressed HCC EMT (Epithelial-Mesenchymal Transition) by increasing E-cadherin and decreasing N-cadherin and vimentin protein expression. Cell proliferation, migration and invasion in vivo were significantly inhibited by the overexpression of XPA, and p-PI3K, p-Akt, and p-mTOR expression were decreased in LV-XPA cells. In general, XPA inhibited HCC by inducing autophagy and apoptosis and by modulating the expression of PI3K/Akt/mTOR proteins.

Conclusions

XPA overexpression was found to suppress HCC by inducing autophagy and apoptosis and repressing EMT and proliferation. Each of these effects may be involved in modulating the PI3K/Akt/mTOR signaling pathway.

Autophagy based cellular physiological strategies target oncogenic progression

Evidence accumulated from past findings indicates that defective proteostasis may contribute to risk factors for cancer generation. Irregular assembly of abnormal proteins catalyzes the disturbance of cellular proteostasis and induces the ability of abnormal cellular proliferation. The autophagy mechanism plays a key role in the regular clearance of abnormal/poor lipids, proteins, and various cellular organelles. The results of functional and effective autophagy deliver normal cellular homeostasis, which establishes supportive metabolism and avoids unexpected tumorigenesis events. Still, the precise molecular mechanism of autophagy in tumor suppression has not been clear. How autophagy triggers selective or nonselective bulk degradation to dissipate tumor promotion under stress conditions is not clear. Under proteotoxic insults to knockdown the drive of tumorigenesis, it is critical for us to figure out the detailed molecular functions of autophagy in human cancers. The current article summarizes autophagy-based theragnostic strategies targeting various phases of tumorigenesis and suggests the preventive roles of autophagy against tumor progression. A better understanding of various molecular partners of autophagic flux will improve and innovate therapeutic approaches based on autophagic-susceptible effects against cellular oncogenic transformation.

Anti-proliferative activity of disulfiram through regulation of the AKT-FOXO axis: A proteomic study of molecular targets

Due to its potent anti-tumor activity, well-investigated pharmacokinetic properties and safety profile, disulfiram (DSF) has emerged as a promising candidate for drug repurposing in cancer therapy. Although several molecular mechanisms have been proposed for its anti-cancer effects, the precise underlying mechanisms remain unclear. In the present study, we showed that DSF inhibited proliferation of cancer cells by inducing reactive oxygen species (ROS) production, a G1 cell cycle arrest and autophagy. Moreover, DSF triggered apoptosis via suppression of the anti-apoptotic protein survivin. To elucidate the mechanisms for the anti-proliferative activities of DSF, we applied a 2-DE combined with MALDI-TOF-MS/MS analysis to identify differentially expressed proteins in breast cancer cells upon treatment with DSF. Nine differentially expressed proteins were identified among which, three candidates including calmodulin (CaM), peroxiredoxin 1 (PRDX1) and collagen type I alpha 1 (COL1A1) are involved in the regulation of the AKT signaling pathway. The results of western blot analysis confirmed that DSF inhibited p-AKT, suggesting that DSF induces its anti-tumor effects via AKT blockade. Moreover, we found that DSF increased the mRNA levels of FOXO1, FOXO3 and FOXO4, and upregulated the expression of their target genes involved in G1 cell cycle arrest, apoptosis and autophagy. Finally, DSF potentiated the anti-proliferative effects of well-known chemotherapeutic agents such as arsenic trioxide (ATO), doxorubicin, paclitaxel and cisplatin. Altogether, these findings provide mechanistic insights into the anti-growth activities of DSF.

An Updated Review on Implications of Autophagy and Apoptosis in Tumorigenesis: Possible Alterations in Autophagy through Engineered Nanomaterials and Their Importance in Cancer Therapy

Most commonly recognized as a catabolic pathway, autophagy is a perplexing mechanism through which a living cell can free itself of excess cytoplasmic components, i.e., organelles, by means of certain membranous vesicles or lysosomes filled with degrading enzymes. Upon exposure to external insult or internal stimuli, the cell might opt to activate such a pathway, through which it can gain control over the maintenance of intracellular components and thus sustain homeostasis by intercepting the formation of unnecessary structures or eliminating the already present dysfunctional or inutile organelles. Despite such appropriateness, autophagy might also be considered a frailty for the cell, as it has been said to have a rather complicated role in tumorigenesis. A merit in the early stages of tumor formation, autophagy appears to be salutary because of its tumor-suppressing effects. In fact, several investigations on tumorigenesis have reported diminished levels of autophagic activity in tumor cells, which might result in transition to malignancy. On the contrary, autophagy has been suggested to be a seemingly favorable mechanism to progressed malignancies, as it contributes to survival of such cells. Based on the recent literature, this mechanism might also be activated upon the entry of engineered nanomaterials inside a cell, supposedly protecting the host from foreign materials. Accordingly, there is a good chance that therapeutic interventions for modulating autophagy in malignant cells using nanoparticles may sensitize cancerous cells to certain treatment modalities, e.g., radiotherapy. In this review, we will discuss the signaling pathways involved in autophagy and the significance of the mechanism itself in apoptosis and tumorigenesis while shedding light on possible alterations in autophagy through engineered nanomaterials and their potential therapeutic applications in cancer. SIGNIFICANCE STATEMENT: Autophagy has been said to have a complicated role in tumorigenesis. In the early stages of tumor formation, autophagy appears to be salutary because of its tumor-suppressing effects. On the contrary, autophagy has been suggested to be a favorable mechanism to progressed malignancies. This mechanism might be affected upon the entry of nanomaterials inside a cell. Accordingly, therapeutic interventions for modulating autophagy using nanoparticles may sensitize cancerous cells to certain therapies.

Atractylodin inhibited the migration and induced autophagy in cholangiocarcinoma cells via PI3K/AKT/mTOR and p38MAPK signalling pathways

OBJECTIVES

The effects of atractylodin (ATD), the bioactive compound from Atractylodes lancea, on migration and autophagy status of cholangiocarcinoma cell line were investigated.

METHODS

Cytotoxic activity and effects on cell migration and invasion were evaluated by MTT and trans-well assay, respectively. Autophagy and underlying molecular mechanisms were investigated using flow cytometry and western blot analysis.

KEY FINDINGS

ATD regulated the activity of PI3K/AKT/mTOR and p38MAPK signalling pathways which contributed to autophagy induction. HuCCT-1 cell growth was inhibited by ATD in a time- and dose-dependent manner. ATD inhibited the migration and invasion of HuCCT1 cells in a concentration-dependent manner. It also induced autophagy in HuCCT1 cells in a time- and dose-dependent manner. The SB202190 (autophagy inducer) and 3-MA (autophagy inhibitor) significantly increased and decreased the rate of ATD-induced autophagy, respectively. The 24 h exposure of ATD inhibited the phosphorylation of phosphatidylinositol-3-kinase (PI3K), protein kinase B (AKT), mammalian target of rapamycin (mTOR), mitogen-activated protein kinase (p38MAPK) and increased Beclin-1 expression and LC3 conversion. It also reduced p-AKT/AKT, p-mTOR/mTOR and p-p38MAPK/p38MAPK.

CONCLUSIONS

ATD inhibits the proliferation and induces CCA cell autophagy via regulating PI3K/AKT/mTOR and p38MAPK signalling pathways.

The disulfiram/copper complex induces apoptosis and inhibits tumor growth in human osteosarcoma by activating the ROS/JNK signaling pathway

Given the huge cost, long research and development (R&D) time and uncertain side effects of discovering new drugs, drug repositioning of those approved to treat diseases clinically as new drugs for other pathological conditions, especially cancers, is a potential alternative strategy. Disulfiram (DSF), an old drug used to treat alcoholism, has been found to exhibit anticancer activity and improve chemotherapeutic efficacy in cancers by an increasing number of studies. In addition, the combination of DSF and copper may be a more effective therapeutic strategy. In this study, we report the toxicity of the DSF/Cu complex to human osteosarcoma both in vitro and in vivo. DSF/Cu significantly inhibited the proliferation and clonogenicity of osteosarcoma cell lines. Furthermore, the generation of ROS was triggered by DSF/Cu, and cell arrest, autophagy and apoptosis were induced in a ROS-dependent manner. The underlying mechanism of this process was explored, and DSF/Cu may mainly inhibit osteosarcoma by inducing apoptosis by activating the ROS/JNK pathway. DSF/Cu also inhibited osteosarcoma growth in a xenograft model with low levels of organ-related toxicities. These results suggest that the DSF/Cu complex could be an efficient and safe option for the treatment of osteosarcoma in the clinic.

Autophagy, an accomplice or antagonist of drug resistance in HCC?

Hepatocellular carcinoma (HCC) is a highly lethal malignancy characterized by poor prognosis and a low 5-year survival rate. Drug treatment is proving to be effective in anti-HCC. However, only a small number of HCC patients exhibit sensitive responses, and drug resistance occurs frequently in advanced patients. Autophagy, an evolutionary process responsible for the degradation of cellular substances, is closely associated with the acquisition and maintenance of drug resistance for HCC. This review focuses on autophagic proteins and explores the intricate relationship between autophagy and cancer stem cells, tumor-derived exosomes, and noncoding RNA. Clinical trials involved in autophagy inhibition combined with anticancer drugs are also concerned.

Molecular Mechanism of Autophagy and Its Regulation by Cannabinoids in Cancer

Simple Summary

This review examines the complex function of autophagy in malignancy and explores its regulation by cannabinoids in different cancers. Autophagy is an important process in the maintenance of cellular homeostasis, through the degradation and recycling of cytoplasmic constituents. The action of autophagy is highly dependent on tumour stage and type and the receptors with which ligands interact. Cannabinoids are growingly being acknowledged for their anticancer activities and are known to stimulate several mechanisms such as apoptosis and autophagy. Better understanding the mechanism of action behind autophagy and its regulation by cannabinoids will allow the development of novel cancer therapeutics.

Abstract

Autophagy is a “self-degradation” process whereby malfunctioned cytoplasmic constituents and protein aggregates are engulfed by a vesicle called the autophagosome, and subsequently degraded by the lysosome. Autophagy plays a crucial role in sustaining protein homeostasis and can be an alternative source of energy under detrimental circumstances. Studies have demonstrated a paradoxical function for autophagy in cancer, displaying both tumour suppressive and tumour promotive roles. In early phases of tumour development autophagy promotes cancer cell death. In later phases, autophagy enables cancer cells to survive and withstand therapy. Cannabinoids, which are derivatives of the Cannabis sativa L. plant, have shown to be associated with autophagy induction in cells. There is an emerging interest in studying the signalling pathways involved in cannabinoid-induced autophagy and their potential application in anticancer therapies. In this review, the molecular mechanisms involved in the autophagy degradation process will be discussed. This review also highlights a role for autophagy in cancer progression, with cannabinoid-induced autophagy presenting a novel strategy for anticancer therapy.

Endolysosomal TRPMLs in Cancer

Lysosomes, the degradative endpoints and sophisticated cellular signaling hubs, are emerging as intracellular Ca²⁺ stores that govern multiple cellular processes. Dys-homeostasis of lysosomal Ca²⁺ is intimately associated with a variety of human diseases including cancer. Recent studies have suggested that the Ca²⁺-permeable channels Transient Receptor Potential (TRP) Mucolipins (TRPMLs, TRPML1-3) integrate multiple processes of cell growth, division and metabolism. Dysregulation of TRPMLs activity has been implicated in cancer development. In this review, we provide a summary of the latest development of TRPMLs in cancer. The expression of TRPMLs in cancer, TRPMLs in cancer cell nutrient sensing, TRPMLs-mediated lysosomal exocytosis in cancer development, TRPMLs in TFEB-mediated gene transcription of cancer cells, TRPMLs in bacteria-related cancer development and TRPMLs-regulated antitumor immunity are discussed. We hope to guide readers toward a more in-depth discussion of the importance of lysosomal TRPMLs in cancer progression and other human diseases.

IP3 Receptor Biology and Endoplasmic Reticulum Calcium Dynamics in Cancer

Intracellular Ca²⁺ signaling regulates a plethora of cellular functions. A central role in these processes is reserved for the inositol 1,4,5-trisphosphate receptor (IP₃R), a ubiquitously expressed Ca²⁺-release channel, mainly located in the endoplasmic reticulum (ER). Three IP₃R isoforms (IP₃R1, IP₃R2 and IP₃R3) exist, encoded respectively by ITPR1, ITPR2 and ITPR3. The proteins encoded by these genes are each about 2700 amino acids long and assemble into large tetrameric channels, which form the target of many regulatory proteins, including several tumor suppressors and oncogenes. Due to the important role of the IP₃Rs in cell function, their dysregulation is linked to multiple pathologies. In this review, we highlight the complex role of the IP₃R in cancer, as it participates in most of the so-called "hallmarks of cancer". In particular, the IP₃R directly controls cell death and cell survival decisions via regulation of autophagy and apoptosis. Moreover, the IP₃R impacts cellular proliferation, migration and invasion. Typical examples of the role of the IP₃Rs in these various processes are discussed. The relative levels of the IP₃R isoforms expressed and their subcellular localization, e.g. at the ER-mitochondrial interface, is hereby important. Finally, evidence is provided about how the knowledge of the regulation of the IP₃R by tumor suppressors and oncogenes can be exploited to develop novel therapeutic approaches to fight cancer.

The Role of Autophagy in Liver Cancer: Crosstalk in Signaling Pathways and Potential Therapeutic Targets

Autophagy is an evolutionarily conserved lysosomal-dependent pathway for degrading cytoplasmic proteins, macromolecules, and organelles. Autophagy-related genes (Atgs) are the core molecular machinery in the control of autophagy, and several major functional groups of Atgs coordinate the entire autophagic process. Autophagy plays a dual role in liver cancer development via several critical signaling pathways, including the PI3K-AKT-mTOR, AMPK-mTOR, EGF, MAPK, Wnt/β-catenin, p53, and NF-κB pathways. Here, we review the signaling pathways involved in the cross-talk between autophagy and hepatocellular carcinoma (HCC) and analyze the status of the development of novel HCC therapy by targeting the core molecular machinery of autophagy as well as the key signaling pathways. The induction or the inhibition of autophagy by the modulation of signaling pathways can confer therapeutic benefits to patients. Understanding the molecular mechanisms underlying the cross-link of autophagy and HCC may extend to translational studies that may ultimately lead to novel therapy and regimen formation in HCC treatment.

A Prognostic Model for Colon Cancer Patients Based on Eight Signature Autophagy Genes

Objective

To screen key autophagy genes in colon cancer and construct an autophagy gene model to predict the prognosis of patients with colon cancer.

Methods

The colon cancer data from the TCGA were downloaded as the training set, data chip of GSE17536 as the validation set. The differential genes of the training set were obtained and were analyzed for enrichment and protein network. Acquire autophagy genes from Human Autophagy Database www.autophagy.lu/project.html. Autophagy genes in differentially expressed genes were extracted using R-packages limma. Using LASSO/Cox regression analysis combined with clinical information to construct the autophagy gene risk scoring model and divide the samples into high and low risk groups according to the risk value. The Nomogram assessment model was used to predict patient outcomes. CIBERSORT was used to calculate the infiltration of immune cells in the samples and study the relationship between high and low risk groups and immune checkpoints.

Results

Nine hundred seventy-six differentially expressed genes were screened from training set, including five hundred sixty-eight up-regulated genes and four hundred eight down regulated genes. These differentially expressed genes were mainly involved: the regulation of membrane potential, neuroactive ligand-receptor interaction. We identified eight autophagy genes CTSD, ULK3, CDKN2A, NRG1, ATG4B, ULK1, DAPK1, and SERPINA1 as key prognostic genes and constructed the model after extracting the differential autophagy genes in the training set. Survival analysis showed significant differences in sample survival time after grouping according to the model. Nomogram assessment showed that the model had high reliability for predicting the survival of patients with colon cancer in the 1, 3, 5 years. In the high-risk group, the infiltration degrees of nine types of immune cells are different and the samples can be well distinguished according to these nine types of immune cells. Immunological checkpoint correlation results showed that the expression levels of CTLA4, IDO1, LAG3, PDL1, and TIGIT increased in high-risk groups.

Conclusion

The prognosis prediction model based on autophagy gene has a good evaluation effect on the prognosis of colon cancer patients. Eight key autophagy genes can be used as prognostic markers for colon cancer.