Autophagy Inhibition Delays Early but Not Late-Stage Metastatic Disease

Simulated microgravity activates autophagy expression in the rat retina

OBJECTIVE

This study aims to investigate the expression and possible role of autophagy in the retina of rats under microgravity.

METHODS

Adult Sprague-Dawley (SD) rats were randomly allocated to either the tail suspension group (TS) or the control group (CTRL). To simulate microgravity-induced redistribution of cephalad fluid observed in space, the rats in the TS group underwent tail suspension for a duration of 4 weeks. Optical coherence tomography angiography (OCTA) was applied to assess the ocular blood flow and thickness of the retina. Hematoxylin and eosin (H&E) staining, along with transmission electron microscopy (TEM), were used to investigate morphological changes and autophagosomes in the retina. Endoplasmic reticulum autophagy (ER-phagy) related proteins (ATF4, CHOP, and GRP78) in the rat retina were detected using an immunofluorescence assay (IFA). The levels of autophagy-related proteins (Beclin1, P62, LC3B, ATF4, CHOP, and GRP78) were quantified by Western blot (WB). The expression of ATG5 and ATG7 genes was examined via real-time quantitative PCR (qPCR).

RESULTS

In fundus imaging signs, microgravity increases retinal thickness and the retinal vascular perfusion area. Moreover, microgravity also upregulates Beclin1, LC3B, ATF4, CHOP, and GRP78 while downregulating P62 in retina. It elevates the number of autophagosomes and activates autophagy and ER-phagy signaling pathways in retina.

CONCLUSION

Simulated microgravity can trigger the organism's intrinsic protective mechanisms, inducing the activation of autophagy (ER-phagy) in the retina, which may represent a self-defense mechanism against adverse conditions of microgravity-related stressors.

Protocatechualdehyde induced tumor suppressive autophagy through AMPK/ULK1 signaling pathway in gastric cancer

Background

Gastric cancer (GC) is one of the primary causes of cancer-related fatalities, which requires novel treatment including traditional Chinese medicine (TCM) to prolong survival. Protocatechualdehyde (PCA), a monomer from Chinese herbs, exhibits an anti-cancer effect by inhibiting proliferation and migration, or inducing apoptosis in various types of tumors. However, the anti-cancer effect and underlying mechanism of PCA in gastric cancer are still unclear.

Methods

The cell proliferation ability was detected by the cell counting kit-8 (CCK-8) and colony formation. The occurrence of autophagy was observed by TEM (Tansmission electron microscopy) and immunofluorescence. The expression of proteins involved in AMPK/mTOC1 signaling pathway was detected by western blotting. Apoptosis and cell cycle analysis were determined through flow cytometry. A xenograft mouse model was employed to validate the anticancer effect of PCA in vivo.

Results

PCA was first identified as a specific inhibitor to gastric cancer cells that significantly inhibited the proliferation of human gastric cancer cells MKN45 and AGS in a dose- and time-dependent manner, but not that of human gastric epithelial cells. Furthermore, PCA induced tumor suppressive autophagy in both gastric cancer cells, and blockage of the autophagy by silencing ATG5 can partially reverse the proliferation inhibition of PCA. Mechanistically, PCA induced-autophagy was largely dependent on the activation of the AMPK/ULK1 signaling pathway, and blockage of the pathway through AMPK specific inhibitor Compound C (Com C) or siRNAs targeting ULK1 prevented the occurrence of autophagy and partially reversed the proliferation inhibition induced by PCA. In addition, PCA significantly suppressed the growth of gastric cancer in the gastric cancer xenograft mouse model by activating key proteins related to the AMPK/ULK1 signaling pathway of autophagy.

Conclusion

These findings demonstrated that PCA inhibited gastric cancer by inducing tumor suppressive autophagy through the AMPK/ULK1 signaling pathway. PCA may serve as a novel candidate for the treatment of gastric cancer.

The Role of A20 in Cancer: Friend or Foe?

A20 is a ubiquitin-editing enzyme that has emerged as a key regulator of inflammatory signaling with paradoxical roles in cancer. Acting as both an oncogene and a tumor suppressor gene depending on the cellular context, A20 modulates important cell pathways, such as NF-κB signaling and autophagy. In this review, we summarize the dual roles of A20 in tumorigenesis, highlighting its ability to promote tumor progression in cancers, such as breast and melanoma, while functioning as a tumor suppressor in lymphomas and hepatocellular carcinoma. We discuss the interplay of A20 with autophagy, a process that is important for maintaining cellular homeostasis and influencing tumor dynamics. By integrating recent findings, we provide insight into how dysregulation of A20 and its associated pathways can either suppress or drive cancer development, which may lead to improved therapeutic intervention.

Metabolic interplays between the tumour and the host shape the tumour macroenvironment

Metabolic reprogramming of cancer cells and the tumour microenvironment are pivotal characteristics of cancers, and studying these processes offer insights and avenues for cancer diagnostics and therapeutics. Recent advancements have underscored the impact of host systemic features, termed macroenvironment, on facilitating cancer progression. During tumorigenesis, these inherent features of the host, such as germline genetics, immune profile and the metabolic status, influence how the body responds to cancer. In parallel, as cancer grows, it induces systemic effects beyond the primary tumour site and affects the macroenvironment, for example, through inflammation, the metabolic end-stage syndrome of cachexia, and metabolic dysregulation. Therefore, understanding the intricate metabolic interplay between the tumour and the host is a growing frontier in advancing cancer diagnosis and therapy. In this Review, we explore the specific contribution of the metabolic fitness of the host to cancer initiation, progression and response to therapy. We then delineate the complex metabolic crosstalk between the tumour, the microenvironment and the host, which promotes disease progression to metastasis and cachexia. The metabolic relationships among the host, cancer pathogenesis and the consequent responsive systemic manifestations during cancer progression provide new perspectives for mechanistic cancer therapy and improved management of patients with cancer.

Enhancing autophagy mitigates LPS-induced neuroinflammation by inhibiting microglial M1 polarization and neuronophagocytosis

Background

Autophagy, a regulator of inflammation, has been implicated in various central nervous system pathologies. Despite this, the role and mechanisms of autophagy in lipopolysaccharide (LPS)-induced neuroinflammation are not clear. This study investigated whether autophagy can play a neuroprotective role in LPS-induced neuroinflammation.

Methods

Primary microglial cells and male C57BL/6 J mice were treated with LPS, autophagy inhibitors (3-methyladenine, 3-MA), or autophagy activators (rapamycin). Cell viability, NF-κB pathway activation, pro-inflammatory cytokine expression, M1 polarization, autophagy markers, and neuronal damage were evaluated via various techniques including CCK-8 assay, Western blot analysis, ELISA, immunohistochemistry, and histological staining.

Results

LPS (1 μg/mL) effectively inhibited cell viability, stimulated the expression of IκB-α and NF-κB, and simultaneously suppressed autophagy protein expression. The pro-inflammatory cytokines IL-1β and IL-6 showed a significant increase. Contrary to the effect of 3-MA, the rapamycin treatment inhibited the polarization of microglia cells to the M1 type in the various groups of microglia cells after LPS stimulation. This was evidenced by decreased expression of cytokines IL-1β, IL-6, and CD86, and increased expression of Arg-1, IL-10, and CD206. In vivo experiments found that mice with injections of LPS and 3-MA in the lateral ventricle showed significantly increased expression of IκB-α and NF-κB in brain tissues, elevated levels of pro-inflammatory cytokines, decreased autophagy levels, and increased necrotic neurons. There was increased aggregation of microglia cells and increased neuronophagocytosis. Conversely, mice injected with rapamycin showed enhanced neuronal cell autophagy, decreased expression of pro-inflammatory cytokines and apoptosis, and reduced neuronophagocytosis.

Conclusion

Enhancing autophagy can effectively mitigate LPS-induced neuroinflammation by inhibiting microglial M1 polarization and neuronophagocytosis, thereby protecting neuronal integrity. These findings suggest potential therapeutic strategies targeting autophagy in neuroinflammatory conditions.

Triptolide's impact on ACER1 signaling: Inducing autophagy for triple-negative breast cancer suppression

Given the absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (Her-2) in triple-negative breast cancer (TNBC) cells, the efficacy of targeted therapies is limited. In this study, we uncovered that triptolide (TP) effectively suppresses the migration and invasiveness of MDA-MB-231 cells by activating autophagic pathways. Western blotting analysis revealed that TP significantly reduced the expression levels of p62 protein, while simultaneously markedly increasing the expression levels of LC3B-II, BNIP3, BNIP3L, ATG5, and ULK1 proteins, strongly suggesting an enhancement of autophagic activity in the cells. Based on PCR array screening, we identified the ACER1 gene as exhibiting notable expression alterations post-TP treatment. Overexpression of ACER1 gene enhanced the TP-induced apoptosis in MDA-MB-231 cells and augmented the regulation of autophagy-related proteins p62 and LC3B-II, leading to an increase in autophagosome numbers and a marked reduction in cellular migration and invasiveness. Conversely, ACER1 gene knockdown reversed these effects. In vivo experiments demonstrated that TP effectively inhibits the growth of MDA-MB-231 xenograft tumors, concurrently upregulating ACER1 and LC3B-II expression in tumor tissues, while p62 protein levels were notably decreased. Hematoxylin and eosin (H&E) staining results indicated no evident toxicity in liver and kidney tissues of BALB/c mice at a TP dose of 0.4 mg/kg. This study, for the first time, elucidates a novel mechanism by which TP inhibits TNBC through an autophagic process mediated by ACER1.

CircBIRC6 affects prostate cancer progression by regulating miR-574-5p and DNAJB1

BACKGROUND

Prostate cancer (PCa) is among the three main types of cancer. Although prostate-specific antigen (PSA) is routinely tested, it has disadvantages, such as poor prognostic ability. Therefore, finding more PCa markers and therapeutic targets remains a subject of study. CircRNAs have been found to have regulatory roles in various diseases, such as diabetes, Central Nervous System (CNS) neuropathy, etc. where their application in cancer is even more valuable. Therefore, this paper aims to search for differentially expressed circRNAs in PCa and find downstream targeting pathways related to autophagy.

METHOD

By detecting the expression of circRNA in the samples, hsa_circ_0119816 was finally identified as the research target. The properties of circRNA were verified by RNase R, actinomycin D, and fluorescence in situ hybridization (FISH). The downstream target miRNAs and target proteins were predicted by an online database, and the targeting relationship was verified using dual luciferase and RNA Immunoprecipitation. The effects of circRNAs and their downstream signalling pathways on prostate cancer cell proliferation, migration, EMT and autophagy were examined by CCK-8, Transwell, immunofluorescence and Western blotting.

RESULTS

CircBIRC6 is highly expressed in prostate cancer samples. Knockdown of its expression inhibits cell proliferation, invasion, EMT and autophagy and promotes apoptosis. CircBIRC6/miRNA-574-5p/DNAJB1 is a molecular axis that regulates prostate cancer cells.

The role of autophagy related 12 (ATG12) in the progression of hepatocellular carcinoma and its prognostic value

The aim of our research was to explore the character of autophagy related 12 (ATG12) in the development of hepatocellular carcinoma (HCC). A total of  145 HCC tissues as well as paired adjacent normal tissues were collected, then immunohistochemistry was conducted to access the expression of ATG12. HCC cells were transfected with pcDNA ATG12 or si-ATG12 to overexpress ATG12 or downregulate ATG12. The vitality of HCC cells was accessed using CCK-8 assay, and the ability of invasion of them was tested through Transwell assay. The apoptotic rate of HCC cells was calculated by flow cytometry. The expression of ATG12 was lower in HCC tissues than that in normal tissues, and HCC patients with high ATG12 level survived longer. Overexpressed of ATG12 restrained vitality and invasion of HCC cells, while elevated apoptotic rate of HCC cells. Silence of ATG12 expression yielded opposite results to overexpression of ATG12 in HCC cells. In conclusion, ATG12 is low expressed in HCC, which attenuated the growth and invasion of HCC, while induced the apoptosis of HCC cells. Current research suggested that ATG12 might be a potential target for the diagnosis and treatment of HCC.

ASPH dysregulates cell death and induces chemoresistance in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is resistant to multiple conventional drugs including sorafenib, leading to poor prognosis. Inducing cell death has been inextricably pursued in therapeutics, although targeted therapy and immunotherapy have made very limited progress. ASPH (Aspartate β-hydroxylase) can be breakthrough in meeting this unmet clinical need. In HCC, high expression of ASPH enhanced proliferation, migration and invasion. High levels of ASPH predicted worse clinical outcomes of sorafenib-treated HCC patients. Mechanistically, ASPH upregulated SQSTM1/P62 and SLC7A11-GPX4 axis, thereby promoting tumor cell autophagy but blocking ferroptosis. Sorafenib-induced enhancement of autophagy was attenuated by knockout (KO) of ASPH, resulting in sensitization of tumor cells to sorafenib. By silencing ASPH combined with sorafenib, senescence, apoptosis and ferroptosis were mediated, whereas proliferation, migration, invasion, tube formation and stemness were inhibited. As validated by in vivo murine models of HCC, ASPH promoted tumor growth, distant metastasis, and resistance to sorafenib. By contrast, KO ASPH combined with sorafenib effectively inhibited tumor development and progression, including intrahepatic, pulmonary, and splenic metastases. Targeting ASPH generated antitumor efficacy will pave the way for HCC therapy.

The dual role of autophagy in suppressing and promoting hepatocellular carcinoma

The 5-year survival rate for hepatocellular carcinoma (HCC), a deadly form of liver cancer, is quite low. Although drug therapy is successful, patients with advanced liver cancer frequently develop resistance because of the significant phenotypic and genetic heterogeneity of these cells. The overexpression of drug efflux transporters, downstream adaptive responses, malfunctioning DNA damage repair, epigenetic modification, the tumor microenvironment, and the extracellular matrix can all be linked to drug resistance. The evolutionary process of autophagy, which is in charge of intracellular breakdown, is intimately linked to medication resistance in HCC. Autophagy is involved in both the promotion and suppression of cancer by influencing treatment resistance, metastasis, carcinogenesis, and the viability of stem cells. Certain autophagy regulators are employed in anticancer treatment; however, because of the dual functions of autophagy, their use is restricted, and therapeutic failure is increased. By focusing on autophagy, it is possible to reduce HCC expansion and metastasis, and enhance tumor cell reactivity to treatment. Macroautophagy, the best-characterized type of autophagy, involves the formation of a sequestering compartment termed a phagophore, which surrounds and encloses aberrant or superfluous components. The phagophore matures into a double-membrane autophagosome that delivers the cargo to the lysosome; lysosomes and autophagosomes fuse to degrade and recycle the cargo. Macroautophagy plays dual functions in both promoting and suppressing cancer in a variety of cancer types.

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.

HDAC2 promotes autophagy-associated HCC malignant progression by transcriptionally activating LAPTM4B

Hepatocellular carcinoma (HCC) is a significant global health challenge. The activation of autophagy plays an essential role in promoting the proliferation and survival of cancer cells. However, the upstream regulatory network and mechanisms governing autophagy in HCC remain unclear. This study demonstrated that histone deacetylase 2 (HDAC2) regulates autophagy in HCC. Its expression was elevated in HCC tissues, and high HDAC2 expression was strongly associated with poor prognosis in individuals with HCC. Integrated in vitro and in vivo investigations confirmed that HDAC2 promotes autophagy and autophagy-related malignant progression in HCC. Mechanistically, HDAC2 bound specifically to the lysosome-associated protein transmembrane 4-β (LAPTM4B) promoter at four distinct binding sites, enhancing its transcriptional activation and driving autophagy-related malignant progression in HCC. These findings establish LAPTM4B as a direct target gene of HDAC2. Furthermore, the selective inhibitor of HDAC2 effectively alleviated the malignant development of HCC. In addition, multivariate Cox regression analysis of 105 human HCC samples revealed that HDAC2 expression is an independent predictor of HCC prognosis. This study underscores the crucial role of the HDAC2-LAPTM4B axis in regulating autophagy in the malignant evolution of HCC and highlights the potential of targeting HDAC2 to prevent and halt the malignant progression of HCC.

In vitro study of the expression of autophagy genes ATG101, mTOR and AMPK in breast cancer with treatment of lactoferrin and in silico study of their communication networks and protein interactions

Autophagy is a new window of science that has been noticed due to the importance of specific therapies in cancer. In this study, the effect of lactoferrin (Lf) on the expression level of ATG101, mTOR and AMPK genes in breast cancer cell line MCF7, as well as the interaction between lactoferrin protein and their protein were investigated. The expression level of the genes was measured using a real-time PCR method. PDB, UniProt, KEGG, and STRING databases and ClusPro webserver and PyMol software were used in silico study. The results showed that the expression level of the ATG101 gene in treatment with concentrations of 100, 400, 600, and 800 μg/ml Lf decreased by 0.05, 0.13, 0.54 and 0.77, respectively. The expression level of the mTOR gene in treatment with concentrations of 100, 400, 600, and 800 μg/ml Lf decreased by 0.07, 0.05, 0.13, and 0.49 times respectively. The level of the AMPK gene expression in treatment with concentrations of 100, 400, 600, and 800 μg/ml Lf decreased by 0.05, 0.01, 0.06, and 0.03, respectively. Virtualization of the interaction of Lf protein with ATG101, mTOR and AMPK proteins by Pymol software showed that the N lobe region of Lf interacted with the HORMA domain of ATG101 protein, the fat domain of mTOR protein, and the CTD domain of AMPK protein. Although Lf was not able to increase the expression of autophagy-inducing genes, it may be able to induce autophagy through protein interaction by activating or inhibiting proteins related to autophagy regulation.

Enhancing Therapeutic Efficacy in Cancer Treatment: Integrating Nanomedicine with Autophagy Inhibition Strategies

The complicated stepwise lysosomal degradation process known as autophagy is in charge of destroying and eliminating damaged organelles and defective cytoplasmic components. This mechanism promotes metabolic adaptability and nutrition recycling. Autophagy functions as a quality control mechanism in cells that support homeostasis and redox balance under normal circumstances. However, the role of autophagy in cancer is controversial because, mostly depending on the stage of the tumor, it may either suppress or support the disease. While autophagy delays the onset of tumors and slows the dissemination of cancer in the early stages of tumorigenesis, numerous studies demonstrate that autophagy promotes the development and spread of tumors as well as the evolution and development of resistance to several anticancer drugs in advanced cancer stages. In this Review, we primarily emphasize the therapeutic role of autophagy inhibition in improving the treatment of multiple cancers and give a broad overview of how its inhibition modulates cancer responses. There have been various attempts to inhibit autophagy, including the use of autophagy inhibitor drugs, gene silencing therapy (RNA interference), and nanoparticles. In this Review, all these topics are thoroughly covered and illustrated by recent studies and field investigations.

Critical roles of lncRNA-mediated autophagy in urologic malignancies

Urologic oncology is a significant public health concern on a global scale. Recent research indicates that long chain non-coding RNAs (lncRNAs) and autophagy play crucial roles in various cancers, including urologic malignancies. This article provides a summary of the latest research findings, suggesting that lncRNA-mediated autophagy could either suppress or promote tumors in prostate, kidney, and bladder cancers. The intricate network involving different lncRNAs, target genes, and mediated signaling pathways plays a crucial role in urological malignancies by modulating the autophagic process. Dysregulated expression of lncRNAs can disrupt autophagy, leading to tumorigenesis, progression, and enhanced resistance to therapy. Consequently, targeting particular lncRNAs that control autophagy could serve as a dependable diagnostic tool and a promising prognostic biomarker in urologic oncology, while also holding potential as an effective therapeutic approach.

Glutathione Depletion and Stalwart Anticancer Activity of Metallotherapeutics Inducing Programmed Cell Death: Opening a New Window for Cancer Therapy

The cellular defense system against exogenous substances makes therapeutics inefficient as intracellular glutathione (GSH) exhibits an astounding antioxidant activity in scavenging reactive oxygen species (ROS) or reactive nitrogen species (RNS) or other free radicals produced by the therapeutics. In the cancer cell microenvironment, the intracellular GSH level becomes exceptionally high to fight against oxidative stress created by the production of ROS/RNS or any free radicals, which are the byproducts of intracellular redox reactions or cellular respiration processes. Thus, in order to maintain redox homeostasis for survival of cancer cells and their rapid proliferation, the GSH level starts to escalate. In this circumstance, the administration of anticancer therapeutics is in vain, as the elevated GSH level reduces their potential by reduction or by scavenging the ROS/RNS they produce. Therefore, in order to augment the therapeutic potential of anticancer agents against elevated GSH condition, the GSH level must be depleted by hook or by crook. Hence, this Review aims to compile precisely the role of GSH in cancer cells, the importance of its depletion for cancer therapy and examples of anticancer activity of a few selected metal complexes which are able to trigger cancer cell death by depleting the GSH level.

Pirin Promotes the Progression of Non-Small-Cell Lung Cancer by Increasing ODC1 to Suppress Autophagy

Non-small-cell lung cancer (NSCLC), a common malignant tumor, requires deeper pathogenesis investigation. Autophagy is an evolutionarily conserved lysosomal degradation process that is frequently blocked during cancer progression. It is an urgent need to determine the novel autophagy-associated regulators in NSCLC. Here, we found that pirin was upregulated in NSCLC, and its expression was positively correlated with poor prognosis. Overexpression of pirin inhibited autophagy and promoted NSCLC proliferation. We then performed data-independent acquisition-based quantitative proteomics to identify the differentially expressed proteins (DEPs) in pirin-overexpression (OE) or pirin-knockdown (KD) cells. Among the pirin-regulated DEPs, ornithine decarboxylase 1 (ODC1) was downregulated in pirin-KD cells while upregulated along with pirin overexpression. ODC1 depletion reversed the pirin-induced autophagy inhibition and pro-proliferation effect in A549 and H460 cells. Immunohistochemistry showed that ODC1 was highly expressed in NSCLC cancer tissues and positively related with pirin. Notably, NSCLC patients with pirinhigh/ODC1high had a higher risk in terms of overall survival. In summary, we identified pirin and ODC1 as a novel cluster of prognostic biomarkers for NSCLC and highlighted the potential oncogenic role of the pirin/ODC1/autophagy axis in this cancer type. Targeting this pathway represents a possible therapeutic approach to treat NSCLC.

Investigating autophagy and intricate cellular mechanisms in hepatocellular carcinoma: Emphasis on cell death mechanism crosstalk

Hepatocellular carcinoma (HCC) stands as a formidable global health challenge due to its prevalence, marked by high mortality and morbidity rates. This cancer type exhibits a multifaceted etiology, prominently linked to viral infections, non-alcoholic fatty liver disease, and genomic mutations. The inherent heterogeneity of HCC, coupled with its proclivity for developing drug resistance, presents formidable obstacles to effective therapeutic interventions. Autophagy, a fundamental catabolic process, plays a pivotal role in maintaining cellular homeostasis, responding to stressors such as nutrient deprivation. In the context of HCC, tumor cells exploit autophagy, either augmenting or impeding its activity, thereby influencing tumorigenesis. This comprehensive review underscores the dualistic role of autophagy in HCC, acting as both a pro-survival and pro-death mechanism, impacting the trajectory of tumorigenesis. The anti-carcinogenic potential of autophagy is evident in its ability to enhance apoptosis and ferroptosis in HCC cells. Pertinently, dysregulated autophagy fosters drug resistance in the carcinogenic context. Both genomic and epigenetic factors can regulate autophagy in HCC progression. Recognizing the paramount importance of autophagy in HCC progression, this review introduces pharmacological compounds capable of modulating autophagy-either inducing or inhibiting it, as promising avenues in HCC therapy.

Targeting autophagy drug discovery: Targets, indications and development trends

Autophagy plays a vital role in sustaining cellular homeostasis and its alterations have been implicated in the etiology of many diseases. Drugs development targeting autophagy began decades ago and hundreds of agents were developed, some of which are licensed for the clinical usage. However, no existing intervention specifically aimed at modulating autophagy is available. The obstacles that prevent drug developments come from the complexity of the actual impact of autophagy regulators in disease scenarios. With the development and application of new technologies, several promising categories of compounds for autophagy-based therapy have emerged in recent years. In this paper, the autophagy-targeted drugs based on their targets at various hierarchical sites of the autophagic signaling network, e.g., the upstream and downstream of the autophagosome and the autophagic components with enzyme activities are reviewed and analyzed respectively, with special attention paid to those at preclinical or clinical trials. The drugs tailored to specific autophagy alone and combination with drugs/adjuvant therapies widely used in clinical for various diseases treatments are also emphasized. The emerging drug design and development targeting selective autophagy receptors (SARs) and their related proteins, which would be expected to arrest or reverse the progression of disease in various cancers, inflammation, neurodegeneration, and metabolic disorders, are critically reviewed. And the challenges and perspective in clinically developing autophagy-targeted drugs and possible combinations with other medicine are considered in the review.

Linagliptin, a DPP-4 inhibitor, activates AMPK/FOXO3a and suppresses NFκB to mitigate the debilitating effects of diethylnitrosamine exposure in rat liver: Novel mechanistic insights

Accumulating evidence suggests that dysregulation of FOXO3a plays a significant role in the progression of various malignancies, including hepatocellular carcinoma (HCC). FOXO3a inactivation, driven by oncogenic stimuli, can lead to abnormal cell growth, suppression of apoptosis, and resistance to anticancer drugs. Therefore, FOXO3a emerges as a potential molecular target for the development of innovative treatments in the era of oncology. Linagliptin (LNGTN), a DPP-4 inhibitor known for its safe profile, has exhibited noteworthy anti-inflammatory and anti-oxidative properties in previous in vivo studies. Several potential molecular mechanisms have been proposed to explain these effects. However, the capacity of LNGTN to activate FOXO3a through AMPK activation has not been investigated. In our investigation, we examined the potential repurposing of LNGTN as a hepatoprotective agent against diethylnitrosamine (DENA) intoxication. Additionally, we assessed LNGTN's impact on apoptosis and autophagy. Following a 10-week administration of DENA, the liver underwent damage marked by inflammation and early neoplastic alterations. Our study presents the first experimental evidence demonstrating that LNGTN can reinstate the aberrantly regulated FOXO3a activity by elevating the nuclear fraction of FOXO3a in comparison to the cytosolic fraction, subsequent to AMPK activation. Moreover, noteworthy inactivation of NFκB induced by LNGTN was observed. These effects culminated in the initiation of apoptosis, the activation of autophagy, and the manifestation of anti-inflammatory, antiproliferative, and antiangiogenic outcomes. These effects were concomitant with improved liver function and microstructure. In conclusion, our findings open new avenues for the development of novel therapeutic strategies targeting the AMPK/FOXO3a signaling pathway in the management of chronic liver damage.

Anti-Leukemic Attributes of Natural Compounds Targeting Autophagy: A Closer Look into the Molecular Mechanisms

Leukemia is a heterogeneous clonal cancer that affects millions of individuals around the world. Despite substantial breakthroughs in cancer treatment, traditional chemotherapy and radiotherapy remain ineffective, and therapeutic resistance still stands as a big obstacle. As a result, there is an increasing attention being paid currently toward the potency of natural compounds as a complementary or alternative therapy for leukemia. Autophagy, a conserved cellular process where damaged or defective cytosolic components and macromolecules are destroyed and recycled, plays a dual role in promoting or suppressing the continuance of cancer at different junctures of its development. Current studies have reported that autophagy has a cardinal function in the genesis and progression of leukemia, making it a promising target for novel treatments. In this review, we have explored the effectiveness of certain natural compounds, such as curcumin, resveratrol, tanshinone IIA, quercetin, tetrandrine, parthenolide, berberine, pristimerin, and alantolactone, that modulate autophagy and regulate its associated signaling cascades at a molecular level in different types of leukemia. They have been shown to have synergistic effects with conventional chemotherapy, emphasizing their potential as supplementary medicines. However, additional research is required to fully comprehend their mechanisms of action and to maximize their role in clinical perspectives.

The Roles of Autophagy-related miRNAs in Gynecologic Tumors: A Review of Current Knowledge for Possible Targeted Therapy

Gynecological cancers are the leading cause of malignancy-related death and disability in the world. These cancers are diagnosed at end stages, and unfortunately, the standard therapeutic strategies available for the treatment of affected women [including chemotherapy, radiotherapy and surgery] are not safe and effective enough. Moreover, the unwanted side-effects lowering the patients' life quality is another problem for these therapies. Therefore, researchers should search for better alternative/complementary treatments. The involvement of autophagy in the pathogenesis of various cancers has been demonstrated. Recently, a novel crosstalk between microRNAs, small non-coding RNAs with important regulatory functions, and autophagy machinery has been highlighted. In this review, we indicate the importance of this interaction for targeted therapy in the treatment of cancers including gynecological cancers, with a focus on underlying mechanisms.

Deubiquitylase USP31 Induces Autophagy and Promotes the Progression in Lung Squamous Cell Carcinoma Cells by Stabilizing E2F1 Expression

BACKGROUND

Autophagy exerts a vital role in the progression of lung squamous cell carcinoma (LUSC). Ubiquitin-specific peptidase 31 (USP31) has recently been found to be involved in the development of a variety of cancers. However, whether USP31 modulates autophagy in LUSC remains unclear.

METHODS

This study revealed that high levels of USP31 were discovered in LUSC tissue samples employing the Gene Expression Profiling Interactive Analysis (GEPIA) database, quantitative real- time PCR (qRT-PCR), and Western blot analysis. Cell proliferation was tested via cell counting kit 8 (CCK-8) as well as colony formation, demonstrating that USP31-stable knockdown reduced cell viability.

RESULTS

Immunofluorescence analysis illustrated that USP31 knockdown blocked the occurrence of LUSC autophagy. Meanwhile, USP31 has been shown to stabilize the expression of E2F transcription factor 1 (E2F1) through the proteasome pathway. Furthermore, overexpressed E2F1 effectively eliminated the effect of USP31 knockdown on LUSC cell proliferation and autophagy.

CONCLUSION

In summary, this investigation proved that USP31 promoted LUSC cell growth and autophagy, at least in part by stabilizing E2F1 expression, which provided a potential therapeutic gene for the treatment of LUSC.

Anti-IL-8 monoclonal antibodies inhibits the autophagic activity and cancer stem cells maintenance within breast cancer tumor microenvironment

BACKGROUND

Breast cancer tumor microenvironment (TME) is a promising target for immunotherapy. Autophagy, and cancer stem cells (CSCs) maintenance are essential processes involved in tumorigenesis, tumor survival, invasion, and treatment resistance. Overexpression of angiogenic chemokine interleukin-8 (IL-8) in breast cancer TME is associated with oncogenic signaling pathways, increased tumor growth, metastasis, and poor prognosis.

OBJECTIVE

Thus, we aimed to investigate the possible anti-tumor effect of neutralizing antibodies against IL-8 by evaluating its efficacy on autophagic activity and breast CSC maintenance.

METHODS

IL-8 monoclonal antibody supplemented tumor tissue culture systems from 15 females undergoing mastectomy were used to evaluate the expression of LC3B as a specific biomarker of autophagy and CD44, CD24 as cell surface markers of breast CSCs using immunofluorescence technique.

RESULTS

Our results revealed that anti-IL-8 mAb significantly decreased the level of LC3B in the cultured tumor tissues compared to its non-significant decrease in the normal breast tissues.Anti-IL-8 mAb also significantly decreased the CD44 expression in either breast tumors or normal cultured tissues. While it caused a non-significant decrease in CD24 expression in cultured breast tumor tissue and a significant decrease in its expression in the corresponding normal ones.

CONCLUSIONS

Anti-IL-8 monoclonal antibody exhibits promising immunotherapeutic properties through targeting both autophagy and CSCs maintenance within breast cancer TME.

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.

THADA inhibits autophagy and increases 5-FU sensitivity in gastric cancer cells via the PI3K/AKT/mTOR signaling pathway

Objectives

5-Fluorouracil (5-FU) is currently the main drug used in chemotherapy for gastric cancer (GC). The main clinical problems of 5-FU therapy are insensitivity and acquired resistance to 5-FU. The mechanism of GC cell resistance to 5-FU is currently unknown.

Materials and Methods

This study employed next-generation sequencing (NGS) to analyze the differentially expressed genes (DEGs) in chemotherapy-sensitive and non-sensitive GC tissues. In addition, a bioinformatics analysis was conducted using the GC dataset of GEO, and further validated and explored through in vitro experiments.

Results

Thyroid adenoma-associated gene (THADA) was highly expressed in GC tissues from chemotherapy-sensitive patients and was an independent prognostic factor in GC patients receiving postoperative 5-FU adjuvant chemotherapy. Notably, heightened THADA expression in GC cells was associated with the down-regulation of autophagy-related proteins (LC-3, ATG13, ULK1, and TFEB). Furthermore, the PI3K/AKT/mTOR signaling pathway and mTORC1 signaling pathway were remarkably increased in patients with elevated THADA expression. THADA expression was associated with mTOR, the core protein of the mTOR signaling pathway, and related proteins involved in regulating the mTORC1 signaling pathway (mLST8, RHEB, and TSC2). THADA exhibited inhibitory effects on autophagy and augmented the sensitivity of GC cells to 5-FU through the PI3K/AKT/mTOR signaling pathway.

Conclusion

The findings suggest that THADA may be involved in the regulatory mechanism of GC cell sensitivity to 5-FU. Consequently, the detection of THADA in tumor tissues may bring clinical benefits, specifically for 5-FU-related chemotherapy administered to GC patients with elevated THADA expression.

Inflammation-Associated Cytotoxic Agents in Tumorigenesis

Chronic inflammatory processes are related to all stages of tumorigenesis. As inflammation is closely associated with the activation and release of different cytotoxic agents, the interplay between cytotoxic agents and antagonizing principles is highlighted in this review to address the question of how tumor cells overcome the enhanced values of cytotoxic agents in tumors. In tumor cells, the enhanced formation of mitochondrial-derived reactive species and elevated values of iron ions and free heme are antagonized by an overexpression of enzymes and proteins, contributing to the antioxidative defense and maintenance of redox homeostasis. Through these mechanisms, tumor cells can even survive additional stress caused by radio- and chemotherapy. Through the secretion of active agents from tumor cells, immune cells are suppressed in the tumor microenvironment and an enhanced formation of extracellular matrix components is induced. Different oxidant- and protease-based cytotoxic agents are involved in tumor-mediated immunosuppression, tumor growth, tumor cell invasion, and metastasis. Considering the special metabolic conditions in tumors, the main focus here was directed on the disturbed balance between the cytotoxic agents and protective mechanisms in late-stage tumors. This knowledge is mandatory for the implementation of novel anti-cancerous therapeutic approaches.

Oxidative stress and autophagy-mediated immune patterns and tumor microenvironment infiltration characterization in gastric cancer

Recent years have seen a sharp rise in the amount of research on the connection between oxidative stress, autophagy, and cancer cells. However, the significant functions of oxidative stress and autophagy-related genes (OARGs) in gastric cancer (GC) are yet to be investigated integrally. Therefore, it will be a new and promising concept to search for novel OARG-related biomarkers to predict the prognosis and treatment response of GC. First, we assessed changes in prognosis and tumor microenvironment (TME) characteristics across the various oxidative stress and autophagy-related modification patterns based on a detailed analysis of 17 OARGs with prognostic significance of 808 GC samples. We identified three distinct OARG alteration patterns which displayed unique biological characteristics and immune cell infiltration features. Using principal component analysis methods, the OARGscore was developed to evaluate the OARG modification patterns of certain tumors. The negative connection between OARGscore and immune cells was statistically significant. Increased survival, a higher incidence of mutations, and a better response to immunotherapy were all predicted to be related to patients' high-OARGscore. In addition, the candidate chemotherapeutic drugs were predicted using the oncoPredict program. The low-OARGscore group was predicted to benefit more from Ribociclib, Alisertib, Niraparib, Epirubicin, Olaparib, and Axitinib, while patients in the high-OARGscore group were predicted to benefit more from Afatinib, Oxaliplatin, Paclitaxel, 5-Fluorouracil, Dabrafenib and Lapatinib. Our findings offer a specific method for predicting a patient's prognosis and susceptibility to immunotherapy, as well as a promising insight of oxidative stress and autophagy in GC.

Autophagy as a Target for Non-Immune Intrinsic Functions of Programmed Cell Death-Ligand 1 in Cancer

Autophagy is a catabolic process that is essential to the maintenance of homeostasis through the cellular recycling of damaged organelles or misfolded proteins, which sustains energy balance. Additionally, autophagy plays a dual role in modulating the development and progression of cancer and inducing a survival strategy in tumoral cells. Programmed cell death-ligand 1 (PD-L1) modulates the immune response and is responsible for maintaining self-tolerance. Because tumor cells exploit the PD-L1-PD-1 interaction to subvert the immune response, immunotherapy has been developed based on the use of PD-L1-blocking antibodies. Recent evidence has suggested a bidirectional regulation between autophagy and PD-L1 molecule expression in tumor cells. Moreover, the research into the intrinsic properties of PD-L1 has highlighted new functions that are advantageous to tumor cells. The relationship between autophagy and PD-L1 is complex and still not fully understood; its effects can be context-dependent and might differ between tumoral cells. This review refines our understanding of the non-immune intrinsic functions of PD-L1 and its potential influence on autophagy, how these could allow the survival of tumor cells, and what this means for the efficacy of anti-PD-L1 therapeutic strategies.

Autophagy: Regulator of cell death

Autophagy is the process by which cells degrade and recycle proteins and organelles to maintain intracellular homeostasis. Generally, autophagy plays a protective role in cells, but disruption of autophagy mechanisms or excessive autophagic flux usually leads to cell death. Despite recent progress in the study of the regulation and underlying molecular mechanisms of autophagy, numerous questions remain to be answered. How does autophagy regulate cell death? What are the fine-tuned regulatory mechanisms underlying autophagy-dependent cell death (ADCD) and autophagy-mediated cell death (AMCD)? In this article, we highlight the different roles of autophagy in cell death and discuss six of the main autophagy-related cell death modalities, with a focus on the metabolic changes caused by excessive endoplasmic reticulum-phagy (ER-phagy)-induced cell death and the role of mitophagy in autophagy-mediated ferroptosis. Finally, we discuss autophagy enhancement in the treatment of diseases and offer a new perspective based on the use of autophagy for different functional conversions (including the conversion of autophagy and that of different autophagy-mediated cell death modalities) for the clinical treatment of tumors.

Autophagy and Biomaterials: A Brief Overview of the Impact of Autophagy in Biomaterial Applications

Macroautophagy (hereafter autophagy), a tightly regulated physiological process that obliterates dysfunctional and damaged organelles and proteins, has a crucial role when biomaterials are applied for various purposes, including diagnosis, treatment, tissue engineering, and targeted drug delivery. The unparalleled physiochemical properties of nanomaterials make them a key component of medical strategies in different areas, such as osteogenesis, angiogenesis, neurodegenerative disease treatment, and cancer therapy. The application of implants and their modulatory effects on autophagy have been known in recent years. However, more studies are necessary to clarify the interactions and all the involved mechanisms. The advantages and disadvantages of nanomaterial-mediated autophagy need serious attention in both the biological and bioengineering fields. In this mini-review, the role of autophagy after biomaterial exploitation and the possible related mechanisms are explored.

Ferroptosis, autophagy, tumor and immunity

Ferroptosis was first proposed in 2012, a new form of cell death. Autophagy plays a crucial role in cell clearance and maintaining homeostasis. Autophagy is involved in the initial step of ferroptosis under the action of histone elements such as NCOA4, RAB7A, and BECN1. Ferroptosis and autophagy are involved in tumor progression, treatment, and drug resistance in the tumor microenvironment. In this review, we described the mechanisms of ferroptosis, autophagy, and tumor and immunotherapy, respectively, and emphasized the relationship between autophagy-related ferroptosis and tumor.

Autophagy/Mitophagy Regulated by Ubiquitination: A Promising Pathway in Cancer Therapeutics

Autophagy is essential for organismal development, maintenance of energy homeostasis, and quality control of organelles and proteins. As a selective form of autophagy, mitophagy is necessary for effectively eliminating dysfunctional mitochondria. Both autophagy and mitophagy are linked with tumor progression and inhibition. The regulation of mitophagy and autophagy depend upon tumor type and stage. In tumors, mitophagy has dual roles: it removes damaged mitochondria to maintain healthy mitochondria and energy production, which are necessary for tumor growth. In contrast, mitophagy has been shown to inhibit tumor growth by mitigating excessive ROS production, thus preventing mutation and chromosomal instability. Ubiquitination and deubiquitination are important modifications that regulate autophagy. Multiple E3 ubiquitin ligases and DUBs modulate the activity of the autophagy and mitophagy machinery, thereby influencing cancer progression. In this review, we summarize the mechanistic association between cancer development and autophagy/mitophagy activities regulated by the ubiquitin modification of autophagic proteins. In addition, we discuss the function of multiple proteins involved in autophagy/mitophagy in tumors that may represent potential therapeutic targets.

LINC01278 Induces Autophagy to Inhibit Tumour Progression by Suppressing the mTOR Signalling Pathway

Uveal melanoma (UM) is an aggressive intraocular malignant tumour that is closely related to autophagic dysfunction. We aimed to identify autophagy-related long noncoding RNAs (lncRNAs) to elucidate the molecular mechanism of UM. Here, we show that LINC01278 is a new potential biomarker with clinical prognostic value in UM through bioinformatics analysis. Application of an autophagy inhibitor (3-MA) and an autophagy agonist (MG-132) indicated that LINC01278 can inhibit UM cell proliferation, migration, and invasion by inducing autophagy. A xenograft nude mouse model was used to examine the tumorigenesis of UM cells in vivo. Mechanistically, LINC01278 can inhibit the mTOR signalling pathway to activate autophagy, as shown by experiments with an mTOR agonist (MHY1485) and mTOR inhibitor (rapamycin) treatment. Our findings indicate that LINC01278 functions as a tumour suppressor by inhibiting the mTOR signalling pathway to induce autophagy. Targeting the LINC01278-mTOR axis might be a novel and promising therapeutic approach for UM.

Targeting the Interplay of Autophagy and ROS for Cancer Therapy: An Updated Overview on Phytochemicals

Autophagy is an evolutionarily conserved self-degradation system that recycles cellular components and damaged organelles, which is critical for the maintenance of cellular homeostasis. Intracellular reactive oxygen species (ROS) are short-lived molecules containing unpaired electrons that are formed by the partial reduction of molecular oxygen. It is widely known that autophagy and ROS can regulate each other to influence the progression of cancer. Recently, due to the wide potent anti-cancer effects with minimal side effects, phytochemicals, especially those that can modulate ROS and autophagy, have attracted great interest of researchers. In this review, we afford an overview of the complex regulatory relationship between autophagy and ROS in cancer, with an emphasis on phytochemicals that regulate ROS and autophagy for cancer therapy. We also discuss the effects of ROS/autophagy inhibitors on the anti-cancer effects of phytochemicals, and the challenges associated with harnessing the regulation potential on ROS and autophagy of phytochemicals for cancer therapy.

A comprehensive review of the relationship between autophagy and sorafenib-resistance in hepatocellular carcinoma: ferroptosis is noteworthy

Patients with hepatocellular carcinoma (HCC) bear a heavy burden of disease and economic burden but have fewer treatment options. Sorafenib, a multi-kinase inhibitor, is the only approved drug that can be used to limit the progression of inoperable or distant metastatic HCC. However, enhanced autophagy and other molecular mechanisms after sorafenib exposure further induce drug resistance in HCC patients. Sorafenib-associated autophagy also generates a series of biomarkers, which may represent that autophagy is a critical section of sorafenib-resistance in HCC. Furthermore, many classic signaling pathways have been found to be involved in sorafenib-associated autophagy, including the HIF/mTOR signaling pathway, endoplasmic reticulum stress, and sphingolipid signaling, among others. In turn, autophagy also provokes autophagic activity in components of the tumor microenvironment, including tumor cells and stem cells, further impacting sorafenib-resistance in HCC through a special autophagic cell death process called ferroptosis. In this review, we summarized the latest research progress and molecular mechanisms of sorafenib-resistance-associated autophagy in detail, providing new insights and ideas for unraveling the dilemma of sorafenib-resistance in HCC.

The role of autophagy in acute myeloid leukemia development

INTRODUCTION

Autophagy is a highly conservative self-degradative process. It aims at elimination-impaired proteins and cellular organelles. Previous research confirmed the autophagy role in cancer pathogenesis.

AREAS COVERED

This article discusses the role of autophagy in the development of AML. Autophagy seems to be a 'double-sword' mechanism, hence, either its suppression or induction could promote neoplasm growth. This mechanism could also be the aim of the 'molecular targeted therapy.' Chemo- and radiotherapy induce cellular stress in neoplasm cells with subsequent autophagy suppression. Simultaneously, it is claimed that the autophagy suppression increases chemosensitivity 'in neoplastic cells. Some agents, like bortezomib, in turn could promote autophagy process, e.g. in AML (acute myeloid leukemia). However, currently there are not many studies focusing on the role of autophagy in patients suffering for AML. In this review, we summarize the research done so far on the role of autophagy in the development of AML.

EXPERT OPINION

The analysis of autophagy genes expression profiling in AML could be a relevant factor in the diagnostic process and treatment 'individualization.' Autophagy modulation seems to be a relevant target in the oncological therapy - it could limit disease progression and increase the effectiveness of treatment.

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.

Characteristic of Molecular Subtypes in Lung Squamous Cell Carcinoma Based on Autophagy-Related Genes and Tumor Microenvironment Infiltration

Background

Recently, a large number of studies have sought personalized treatment for lung squamous cell carcinoma (LUSC) by dividing patients into different molecular subtypes. Autophagy plays an important role in maintaining the tumor microenvironment and immune-related biological processes. However, the molecular subtypes mediated by autophagy in LUSC are not clear.

Methods

Based on 490 LUSC samples, we systematically analyzed the molecular subtype modification patterns mediated by autophagy-related genes. The ssGSEA and CIBERSORT algorithm were utilized to quantify the relative abundance of TME cell infiltration. Principal component analysis was used to construct autophagy prognostic score (APS) model.

Results

We identified three autophagy subtypes in LUSC, and their clinical outcomes and TME cell infiltration had significant heterogeneity. Cluster A was rich in immune cell infiltration. The enrichment of EMT stromal pathways and immune checkpoint molecules were significantly enhanced, which may lead to its immunosuppression. Cluster B was characterized by relative immunosuppression and relative stromal activation. Cluster C was activated in biological processes related to repair. Patients with high APS were significantly positively correlated with TME stromal activity and poor survival. Meanwhile, high APS showed an advantage in response to anti-PD1 and anti-CTLA4 immunotherapy.

Conclusion

This study explored the autophagy molecular subtypes in LUSC. We also discovered the heterogeneity of TME cell infiltration driven by autophagy-related genes. The established APS model is of great significance for evaluating the prognosis of LUSC patients, the infiltration of TME cells, and the effect of immunotherapy.

4-Hydroxyisoleucine inhibits tumor growth by triggering endoplasmic reticulum stress and autophagy

4-Hydroxyisoleucine（4-HIL）is a non-protein amino acid that is able to reduce obesity and improve insulin sensitivity in mice, and recently emerged as a drug candidate against hypoglycemia. For the first time, we found that 4-HIL exhibits a potent anti-tumor activity in various cancer cell lines in vitro and in vivo. Most importantly, 4-HIL has no cytotoxic effect on normal or non-malignant cells. Proteomic data analysis revealed changes in endoplasmic reticulum stress（ERS）related protein and autophagy related protein. Western blot revealed that molecular components of the ERS pathway were activated, including phosphorylation of perk and EIF2a increased, while levels of GRP78 reduced, the cellular process of ERS potentially contributed to the activation of autophagy, Transmission electron microscopy revealed the formation of autophagic vesicles under 4-HIL treatment, and LC3B was increased. Meanwhile, activation of ERS inhibits intracellular protein synthesis rate, our results suggest that 4-HIL exhibits anti-tumor activity in various cancer cell lines by increasing ERS and triggering autophagy responses without causing damage to normal cells.

An autophagy-associated lncRNAs model for predicting the survival in non-small cell lung cancer patients

Long non-coding RNAs (lncRNAs) can influence the proliferation, autophagy, and apoptosis of non-small cell lung cancer (NSCLC). LncRNAs also emerge as valuable prognostic factors for NSCLC patients. Consequently, we set out to discover more autophagy-associated lncRNAs. We acquired autophagy-associated genes and information on lncRNAs from The Cancer Genome Atlas database (TCGA), and the Human Autophagy Database (HADb). Then, the prognostic prediction signature was constructed through using co-expression and Cox regression analysis. The signature was constructed including 7 autophagy-associated lncRNAs (ABALON, NKILA, LINC00941, AL161431.1, AL691432.2, AC020765.2, MMP2-AS1). After that, we used univariate and multivariate Cox regression analysis to calculate the risk score. The survival analysis and ROC curve analysis confirmed good performances of the signature. GSEA indicated that the high-risk group was principally enriched in the adherens junction pathway. In addition, biological experiments showed that ABALON promoted the proliferation, metastasis and autophagy levels of NSCLC cells. These findings demonstrate that the risk signature consisting of 7 autophagy-associated lncRNAs accurately predicts the prognosis of NSCLC patients and should be investigated for potential therapeutic targets in clinic.

Inhibiting Cytoprotective Autophagy in Cancer Therapy: An Update on Pharmacological Small-Molecule Compounds

Autophagy is a self-degradation process in which damaged proteins and organelles are engulfed into autophagosomes for digestion and eventually recycled for cellular metabolism to maintain intracellular homeostasis. Accumulating studies have reported that autophagy has the Janus role in cancer as a tumor suppressor or an oncogenic role to promote the growth of established tumors and developing drug resistance. Importantly, cytoprotective autophagy plays a prominent role in many types of human cancers, thus inhibiting autophagy, and has been regarded as a promising therapeutic strategy for cancer therapy. Here, we focus on summarizing small-molecule compounds inhibiting the autophagy process, as well as further discuss other dual-target small-molecule compounds, combination strategies, and other strategies to improve potential cancer therapy. Therefore, these findings will shed new light on exploiting more small-molecule compounds inhibiting cytoprotective autophagy as candidate drugs for fighting human cancers in the future.

Resveratrol as a modulatory of apoptosis and autophagy in cancer therapy

Cancer is one of the leading causes of death, with a heavy socio-economical burden for countries. Despite the great advances that have been made in the treatment of cancer, chemotherapy is still the most common method of treatment. However, many side effects, including hepatotoxicity, renal toxicity, and cardiotoxicity, limit the efficacy of conventional chemotherapy. Over recent years, natural products have attracted attention as therapeutic agents against various diseases, such as cancer. Resveratrol (RES), a natural polyphenol occurring in grapes, nuts, wine, and berries, exhibited potential for preventing and treating various cancer types. RES also ameliorates chemotherapy-induced detrimental effects. Furthermore, RES could modulate apoptosis and autophagy as the main forms of cancer cell deaths by targeting various signaling pathways and up/downregulation of apoptotic and autophagic genes. This review will summarize the anti-cancer effects of RES and focus on the fundamental mechanisms and targets for modulating apoptosis and autophagy by RES.

Autophagy and EMT in cancer and metastasis: Who controls whom?

Metastasis consists of hallmark events, including Epithelial-Mesenchymal Transition (EMT), angiogenesis, initiation of inflammatory tumor microenvironment, and malfunctions in apoptosis. Autophagy is known to play a pivotal role in the metastatic process. Autophagy has pulled researchers towards it in recent times because of its dual role in the maintenance of cancer cells. Evidence states that cells undergoing EMT need autophagy in order to survive during migration and dissemination. Additionally, it orchestrates EMT markers in certain cancers. On the other side of the coin, autophagy plays an oncosuppressive role in impeding early metastasis. This review aims to project the interrelationship between autophagy and EMT. Targeting EMT via autophagy as a useful strategy is discussed in this review. Furthermore, for the first time, we have covered the possible reciprocating roles of EMT and autophagy and its consequences in cancer metastasis.

Punicalagin promotes autophagic degradation of human papillomavirus E6 and E7 proteins in cervical cancer through the ROS-JNK-BCL2 pathway

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This study provides a novel insight into the mechanism of degradation of E6 and E7 caused by punicalagin-induced autophagy. Therefore, our results will offer new strategy for treatment of HPV-infected cervical cancer.

Punicalagin, which is derived from pomegranate peel, is reported to exert growth-inhibitory effects against various cancers. However, the underlying mechanisms have not been elucidated. Human papillomavirus (HPV), a major oncovirus, utilizes the host autophagic machinery to support its replication. Here, punicalagin markedly downregulated the levels of the major HPV oncoproteins E6 and E7 in cervical cancer cells through the autophagy-lysosome system. Additionally, punicalagin activated the reactive oxygen species (ROS)-JNK pathway and promoted the phosphorylation of BCL2, which led to the dissociation of BCL2 from BECN1 and the induction of autophagy. Treatment with autophagy and JNK inhibitors or ROS scavengers mitigated the punicalagin-induced degradation of E6 and E7. Moreover, the knockout of ATG5 using the clustered regularly interspaced palindrome repeat/Cas 9 system mitigated the punicalagin-induced downregulation of E6/E7. This indicated that punicalagin-induced degradation of E6 and E7 was dependent on autophagy. The results of in vivo studies demonstrated that punicalagin efficiently inhibits cervical cancer growth. In conclusion, this study elucidated a mechanism of punicalagin-induced autophagic degradation of E6 and E7. It will enable the future applications of punicalagin as a therapeutic for HPV-induced cervical cancer.

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.

Extracellular matrix guidance of autophagy: a mechanism regulating cancer growth

The extracellular matrix (ECM) exists as a dynamic network of biophysical and biochemical factors that maintain tissue homeostasis. Given its sensitivity to changes in the intra- and extracellular space, the plasticity of the ECM can be pathological in driving disease through aberrant matrix remodelling. In particular, cancer uses the matrix for its proliferation, angiogenesis, cellular reprogramming and metastatic spread. An emerging field of matrix biology focuses on proteoglycans that regulate autophagy, an intracellular process that plays both critical and contextual roles in cancer. Here, we review the most prominent autophagic modulators from the matrix and the current understanding of the cellular pathways and signalling cascades that mechanistically drive their autophagic function. We then critically assess how their autophagic functions influence tumorigenesis, emphasizing the complexities and stage-dependent nature of this relationship in cancer. We highlight novel emerging data on immunoglobulin-containing and proline-rich receptor-1, heparanase and thrombospondin 1 in autophagy and cancer. Finally, we further discuss the pro- and anti-autophagic modulators originating from the ECM, as well as how these proteoglycans and other matrix constituents specifically influence cancer progression.

Autophagy in Tumor Immunity and Viral-Based Immunotherapeutic Approaches in Cancer

Autophagy is a fundamental catabolic process essential for the maintenance of cellular and tissue homeostasis, as well as directly contributing to the control of invading pathogens. Unsurprisingly, this process becomes critical in supporting cellular dysregulation that occurs in cancer, particularly the tumor microenvironments and their immune cell infiltration, ultimately playing a role in responses to cancer therapies. Therefore, understanding "cancer autophagy" could help turn this cellular waste-management service into a powerful ally for specific therapeutics. For instance, numerous regulatory mechanisms of the autophagic machinery can contribute to the anti-tumor properties of oncolytic viruses (OVs), which comprise a diverse class of replication-competent viruses with potential as cancer immunotherapeutics. In that context, autophagy can either: promote OV anti-tumor effects by enhancing infectivity and replication, mediating oncolysis, and inducing autophagic and immunogenic cell death; or reduce OV cytotoxicity by providing survival cues to tumor cells. These properties make the catabolic process of autophagy an attractive target for therapeutic combinations looking to enhance the efficacy of OVs. In this article, we review the complicated role of autophagy in cancer initiation and development, its effect on modulating OVs and immunity, and we discuss recent progress and opportunities/challenges in targeting autophagy to enhance oncolytic viral immunotherapy.