Targeting autophagy in cancer

Dual-Labeled Single Fluorescent Probes for the Simultaneous Two-Color Visualization of Dual Organelles and for Monitoring Cell Autophagy

Dual-labeled single fluorescent probes are powerful tools for studying autophagy on the molecular scale, yet their development has been hampered by design complexity and a lack of valid strategies. Herein, for the first time, we introduce a combinatorial regulation strategy to fabricate dual-labeled probes for studying autophagy by integrating the specific organelle-targeting group and the functional fluorescence switch into a pentacyclic pyrylium scaffold (latent dual-target scaffold). For proof of concept, we prepared a range of dual-labeled probes (TMOs) that display different emission colors in duple organelles. In these probes, TMO1 and TMO2 enabled the simultaneous two-color visualization of the lysosomes and mitochondria. The other probes (TMO3 and TMO4) discriminatively targeted lysosomes/nucleolus and lysosomes/lipid droplets (LDs) with dual-color emission characteristics, respectively. Intriguingly, by simply connecting the endoplasmic reticulum (ER) targeting group to the pentacyclic pyrylium scaffold, we created the first dual-labeled probe TMO5 for simultaneously labeling lysosomes/ER in distinctive fluorescent colors. Subsequently, using the dual-labeled probe TMO2, drug-induced mitophagy was successfully recorded by evaluating the alterations of multiple mitophagy-related parameters, and the mitophagy defects in a cellular model of Parkinson's disease (PD) were also revealed by simultaneous dual-color/dual-organelle imaging. Further, the probe TMO4 can track the movement of lysosomes and LDs in real time and monitor the dynamic process of lipophagy. Therefore, this work not only presents attractive dual-labeled probes to promote the study of organelle interactions during autophagy but also provides a promising combinatorial regulation strategy that may be generalized for designing other dual-labeled probes with multiple organelle combinations.

Discovery of 4-(N-dithiobenzyl piperazine)-1,8-naphthalimide as a potent multi-target antitumor agent with good efficacy, limited toxicity, and low resistance

A series of 4-(N-dithiobenzyl piperazine)-1,8-naphthalimide derivatives 4-6 were designed, synthesized, and evaluated as novel multi-target antitumor agents. 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) results showed that compounds 5j, 5k, and 6j exhibited superior in vitro antiproliferative activity in MGC-803, HepG-2, SKOV-3, and T24 cancer cell lines and the cisplatin-resistant cell line A549/DDP. HepG-2, SKOV-3, and T24 xenograft assay results revealed that compounds 5j, 5k, and 6j exhibited good antitumor effects compared with amonafide. The pathology results indicated that compound 5j exhibited the least comprehensive toxicity among the three compounds, identifying compound 5j as a good candidate antitumor agent with good efficacy, limited toxicity, and low resistance. Compound 5j was thus chose for further antitumor mechanism investigation. Results from the omics research, confocal immunofluorescence, Western blot, transmission electron microscopy, and flow cytometry indicated that compound 5j exerted antitumor effects through multiple mechanisms, including ferroptosis, autophagy, apoptosis, and cell cycle arrest. These results suggest that screening novel 1,8-naphthalimide-based antitumor agents for good efficacy, limited toxicity, and low resistance based on a multi-target drug strategy is feasible.

Hyaluronan nanogel co-loaded with chloroquine to enhance intracellular cisplatin delivery through lysosomal permeabilization and lysophagy inhibition

Hyaluronan (HA) has been widely used to construct nanocarriers for cancer-targeted drug delivery, due to its excellent biocompatibility and intrinsic affinity towards CD44 that is overexpressed in most cancer types. However, the HA-based nanocarriers are prone to trapping in lysosomes following the HA-mediated endocytosis, which limited the delivered drug to access its pharmacological action sites and subsequently compromised the therapeutic efficacy. To overcome this intracellular obstacle, here we demonstrated the co-loading of chloroquine (CQ) in HA nanogel could efficiently promote the intracellular delivery of cisplatin. The cisplatin coordination with HA generated the nanogel that could also co-encapsulate CQ (HA/Cis/CQ nanogel). Compared with cisplatin-loaded HA nanogel (HA/Cis), HA/Cis/CQ significantly promoted the lysosomal escape of cisplatin as well as enhanced tumor inhibition in the triple-negative breast cancer model. Mechanism studies suggested that co-delivery of CQ not only induced the lysosomal membrane permeabilization but also inhibited the lysophagy, which collectively contributed to the lysosomal instability and cisplatin escape. This HA/Cis/CQ nanogel elicited less toxicity compared with the combination of free Cis and CQ, thus suggesting a promising HA nanocarrier to boost the cisplatin delivery towards cancer-targeted therapy.

TRIM3 facilitates ferroptosis in non-small cell lung cancer through promoting SLC7A11/xCT K11-linked ubiquitination and degradation

Ferroptosis, a unique form of regulated necrotic cell death, is caused by excessive iron-dependent lipid peroxidation. However, the underlying mechanisms driving ferroptosis in human cancers remain elusive. In this study, we identified TRIM3, an E3 ubiquitin-protein ligase, as a key regulator of ferroptosis. TRIM3 is downregulated in lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC), two major types of non-small cell lung cancer (NSCLC). Forced expression of TRIM3 promotes cell death by enhancing the cellular level of ROS and lipid peroxidation. Moreover, our in vivo study determined that TRIM3 overexpression diminishes the tumorigenicity of NSCLC cells, indicating that TRIM3 functions as a tumor suppressor in NSCLC. Mechanistically, TRIM3 directly interacts with SLC7A11/xCT through its NHL domain, leading to SCL7A11 K11-linked ubiquitination at K37, which promotes SLC7A11 proteasome-mediated degradation. Importantly, TRIM3 expression exhibits a negative correlation with SCL7A11 expression in clinical NSCLC samples, and low TRIM3 expression is associated with a worse prognosis. This study reveals that TRIM3 functions as a tumor suppressor that can impede the tumorigenesis of NSCLC by degrading SLC7A11, suggesting a novel therapeutic strategy against NSCLC.

Human Chorionic Gonadotropin Regulates the Smad Signaling Pathway by Antagonizing TGF-β in Giant Cell Tumor of Bone

BACKGROUND

Giant cell tumor of bone (GCTB) is a locally aggressive bone tumour aggravated by stromal cell proliferation and metastasis.

OBJECTIVE

We investigated the mechanism of action of human chorionic gonadotropin (HCG) in mediating GCTB proliferation and invasion.

METHODS

The expression of HCG was quantified using quantitative real-time PCR. After the primary stromal cells were isolated and identified, the function of HCG in GCTB was estimated using the cell counting kit-8, flow cytometry, scratch experiment, transwell assay, Western blot, and immunofluorescence. Moreover, the mechanism of HCG was assessed through western blotting.

RESULTS

HCG expression was decreased in clinical tissue samples from patients with GCTB. We validated that HCG repressed stromal cell proliferation, migration, invasion, autophagy, and epithelial- mesenchymal transition (EMT) and promoted cell apoptosis in GCTB. We also verified that HCG repressed the autophagy and EMT of stromal cells through the Smad signaling axis in GCTB. HCG inhibited the transduction of the Smad signaling pathway by restraining the binding of the TGF-β II receptor to ligand Activin A.

CONCLUSION

HCG restrained the Smad signaling pathway by antagonizing TGF-β signaling in GCTB. HCG may serve as a useful patent to treat GCTB.

Jianpi Jiedu Recipe Inhibits Proliferation through Reactive Oxygen Species-Induced Incomplete Autophagy and Reduces PD-L1 Expression in Colon Cancer

BACKGROUND

Jianpi Jiedu Recipe has been used to treat digestive tract tumors in China since ancient times, and its reliability has been proven by clinical research. Currently, the specific biological mechanism of JPJDR in treating tumors is unclear.

METHODOLOGY

CCK-8 assay was used to detect cell viability. Clone formation assay and EdU assay were used to detect cell proliferation potential. DCFH-DA probe and JC-1 probe were used to detect total intracellular reactive oxygen species and mitochondrial membrane potential, respectively. Western blotting and immunofluorescence were used to detect protein expression level and subcellular localization of cells. The RFP-GFP-LC3B reporter system was used to observe the type of autophagy in cells. The xenograft tumor model was used to study the therapeutic effect of JPJDR in vivo.

RESULTS

JPJDR has an excellent inhibitory effect on various colorectal cancer cells and effectively reduces the proliferation ability of HT29 cells. After treatment with JPJDR, the amount of reactive oxygen species in HT29 cells increased significantly, and the mitochondrial membrane potential decreased. JPJDR induced the accumulation of autophagosomes in HT29 cells and was shown to be incomplete autophagy. At the same time, JPJDR reduced the expression of PD-L1. Meanwhile, JPJDR can exert an excellent therapeutic effect in xenograft tumor mice.

CONCLUSION

JPJDR is a low-toxicity and effective anti-tumor agent that can effectively treat colon cancer in vitro and in vivo. Its mechanism may be inducing mitochondrial dysfunction and incomplete autophagy injury to inhibit the proliferation of colon cancer cells.

The Function of Autophagy in the Initiation, and Development of Breast Cancer

Autophagy is a significant catabolic procedure that increases in stressful conditions. This mechanism is mostly triggered after damage to the organelles, the presence of unnatural proteins, and nutrient recycling in reaction to these stresses. One of the key points in this article is that cleaning and preserving damaged organelles and accumulated molecules through autophagy in normal cells helps prevent cancer. Since dysfunction of autophagy is associated with various diseases, including cancer, it has a dual function in tumor suppression and expansion. It has newly become clear that the regulation of autophagy can be used for the treatment of breast cancer, which has a promising effect of increasing the efficiency of anticancer treatment in a tissue- and cell-type-specific manner by affecting the fundamental molecular mechanisms. Regulation of autophagy and its function in tumorigenesis is a vital part of modern anticancer techniques. This study discusses the current advances related to the mechanisms that describe essential modulators of autophagy involved in the metastasis of cancers and the development of new breast cancer treatments.

AUF1-mediated inhibition of autophagic lysosomal degradation contributes to CagA stability and Helicobacter pylori-induced inflammation

CagA, a virulence factor of Helicobacter pylori (H. pylori), is known to drive inflammation in gastric epithelial cells and is typically degraded through autophagy. However, the molecular mechanism by which CagA evades autophagy-mediated degradation remains elusive. This study found that H. pylori inhibits autophagic flux by upregulating the expression of AU-rich element RNA-binding factor 1 (AUF1). We confirmed that AUF1 does not affect autophagy initiation but instead hampers lysosomal clearance, as evidenced by treatments with 3-MA, CQ and BafA1. Upregulated AUF1 stabilizes CagA protein levels by inhibiting the autolysosomal degradation of intracellular CagA in H. pylori-infected gastric epithelial cells. Knocking down AUF1 promotes CagA degradation, an effect that can be reversed by the lysosome inhibitor BafA1 and CQ. Transcriptome analysis of AUF1-knockdown gastric epithelial cells infected with H. pylori indicated that AUF1 regulates the expression of lysosomal-associated hydrolase genes, specifically CTSD, to inhibit autolysosomal degradation. Moreover, we observed that knockdown of AUF1 enhanced the stability of CTSD mRNA and identified AUF1 binding to the 3'UTR region of CTSD mRNA. AUF1-mediated downregulation of CTSD expression contributes to CagA stability, and AUF1 overexpression leads to an increase in CagA levels in exosomes, thus promoting extracellular inflammation. In clinical gastric mucosa, the expression of AUF1 and its cytoplasmic translocation are associated with H. pylori-associated gastritis, with CagA being necessary for the translocation of AUF1 into the cytoplasm. Our findings suggest that AUF1 is a novel host-positive regulator of CagA, and dysregulation of AUF1 expression increases the risk of H. pylori-associated gastritis.

L-Dopa decarboxylase modulates autophagy in hepatocytes and is implicated in dengue virus-caused inhibition of autophagy completion

The enzyme L-Dopa Decarboxylase (DDC) synthesizes the catecholamine dopamine and the indolamine serotonin. Apart from its role in the brain as a neurotransmitter biosynthetic enzyme, DDC has been detected also in the liver and other peripheral organs, where it is implicated in cell proliferation, apoptosis, and host-virus interactions. Dengue virus (DENV) suppresses DDC expression at the later stages of infection, during which DENV also inhibits autophagosome-lysosome fusion. As dopamine affects autophagy in neuronal cells, we investigated the possible association of DDC with autophagy in human hepatocytes and examined whether DDC mediates the relationship between DENV infection and autophagy. We performed DDC silencing/overexpression and evaluated autophagic markers upon induction of autophagy, or suppression of autophagosome-lysosome fusion. Our results showed that DDC favored the autophagic process, at least in part, through its biosynthetic function, while knockdown of DDC or inhibition of DDC enzymatic activity prevented autophagy completion. In turn, autophagy induction upregulated DDC, while autophagy reduction by chemical or genetic (ATG14L knockout) ways caused the opposite effect. This study also implicated DDC with the cellular energetic status, as DDC silencing reduced the oxidative phosphorylation activity of the cell. We also report that upon DDC silencing, the repressive effect of DENV on the completion of autophagy was enhanced, and the inhibition of autolysosome formation did not exert an additive effect on viral proliferation. These data unravel a novel role of DDC in the autophagic process and suggest that DENV downregulates DDC expression to inhibit the completion of autophagy, reinforcing the importance of this protein in viral infections.

Casticin induces apoptosis and cytoprotective autophagy while inhibiting stemness involving Akt/mTOR and JAK2/STAT3 pathways in glioblastoma

Glioblastoma (GBM) is the most common malignant glioma. However, the current systemic drugs cannot completely cure GBM. Casticin is a methoxylated flavonol compound isolated from a traditional Chinese medicine Vitex rotundifolia L.f. and exhibits a strong antitumor activity in multiple human malignancies. This study was aimed to explore the effects and underlying mechanisms of casticin in GBM. The MTT assay and colony formation was used to evaluate the casticin-induced cell viability in GBM cells. Apoptosis was assessed by ANNEXIV/PI staining assay. Autophagy was analyzed by transmission electron microscopy and immunofluorescence assays. GBM stem cell (GSC) was analyzed by tumor-sphere formation assay and ALDEFLUOR assay. The anti-GBM effect of casticin was also determined by the U87MG xenograft model. Casticin inhibited tumor cell growth in vitro and in vivo, as well as significantly induced apoptosis and autophagy. Autophagy inhibition augmented casticin-induced apoptosis. Casticin also reduced the GSC population by suppressing Oct4, Nanog, and Sox2. Mechanistically, casticin inhibited Akt/mTOR and JAK2/STAT3 signal pathways. The antitumor effect of casticin in GBM was demonstrated by inducing apoptosis, autophagy, and reducing population of GSCs; thus, it may be a potential GBM therapeutic agent for future clinical usage.

Britannin suppresses MCF-7 breast cancer cell growth by inducing apoptosis and inhibiting autophagy

Objective

Breast cancer is the main reason for cancer-related death in women. Britannin is a sesquiterpene lactone compound derived from Inula aucheriana with anti-tumor properties. We aimed to explore the impacts of britannin on apoptosis and autophagy in MCF-7 breast cancer cell line.

Materials and Methods

The cytotoxic influences of britannin on MCF-7 cells were estimated by the MTT method. The expression levels of apoptosis-associated genes such as CASP3, BCL2, BCL2L1, STAT3, and JAK2 and transcripts of autophagy markers including ATG1, ATG4, ATG5, ATG7, ATG12, BECN1, and MAP1LC3A were quantified using quantitative real time-PCR (qRT-PCR). Western blotting method was used to evaluate the amount of caspase 3, phosphorylated JAK2, phosphorylated STAT3, ATG1, ATG4, ATG5, Beclin1, and LC-III.

Results

Treatment of MCF-7 cells with various concentrations of britannin remarkably hindered the viability of these cells compared to the controls. This compound significantly elevated the expression of pro-apoptotic caspase-3 but did not influence the levels of anti-apoptotic BCL2 and BCL2L1. Britannin decreased the levels of phosphorylated forms of JAK2 and STAT3 proteins causing the blockage of the JAK/STAT pathway. Four autophagy factors expressions, including ATG4, ATG5, Beclin1, and LCIII, were reduced due to the effect of britannin on MCF-7 cells.

Conclusion

Britannin triggered apoptosis in MCF-7 cells by a mechanism that led to the blockade of the JAK/STAT pathway. Moreover, britannin prohibited autophagy in these cancer cells. This may suggest britannin as an agent for the suppression of breast tumors or as an adjutant for the enhancement of anti-breast cancer drugs effect.

Ferroptosis Inducers as Promising Radiosensitizer Agents in Cancer Radiotherapy

Radiotherapy (RT) failure has historically been mostly attributed to radioresistance. Ferroptosis is a type of controlled cell death that depends on iron and is caused by polyunsaturated fatty acid peroxidative damage. Utilizing a ferroptosis inducer may be a successful tactic for preventing tumor growth and radiotherapy-induced cell death. A regulated form of cell death known as ferroptosis is caused by the peroxidation of phospholipids containing polyunsaturated fatty acids in an iron-dependent manner (PUFA-PLs). The ferroptosis pathway has a number of important regulators. By regulating the formation of PUFA-PLs, the important lipid metabolism enzyme ACSL4 promotes ferroptosis, whereas SLC7A11 and (glutathione peroxidase 4) GPX4 prevent ferroptosis. In addition to introducing the ferroptosis inducer chemicals that have recently been demonstrated to have a radiosensitizer effect, this review highlights the function and methods by which ferroptosis contributes to RT-induced cell death and tumor suppression in vitro and in vivo.

Role of YAP Signaling in Regulation of Programmed Cell Death and Drug Resistance in Cancer

Although recent advances in cancer treatment significantly improved the prognosis of patients, drug resistance remains a major challenge. Targeting programmed cell death is a major approach of antitumor drug development. Deregulation of programmed cell death (PCD) contributes to resistance to a variety of cancer therapeutics. Yes-associated protein (YAP) and its paralog TAZ, the main downstream effectors of the Hippo pathway, are aberrantly activated in a variety of human malignancies. The Hippo-YAP pathway, which was originally identified in Drosophila, is well conserved in humans and plays a defining role in regulation of cell fate, tissue growth and regeneration. Activation of YAP signaling has emerged as a key mechanism involved in promoting cancer cell proliferation, metastasis, and drug resistance. Understanding the role of YAP/TAZ signaling network in PCD and drug resistance could facilitate the development of effective strategies for cancer therapeutics.

MK8722 initiates early-stage autophagy while inhibiting late-stage autophagy via FASN-dependent reprogramming of lipid metabolism

Background and objective: Epithelial ovarian cancer (EOC) is associated with latent onset and poor prognosis, with drug resistance being a main concern in improving the prognosis of these patients. The resistance of cancer cells to most chemotherapeutic agents can be related to autophagy mechanisms. This study aimed to assess the therapeutic effect of MK8722, a small-molecule compound that activates AMP-activated protein kinase (AMPK), on EOC cells and to propose a novel strategy for the treatment of EOC. Purpose: To explore the therapeutic effects of MK8722 on EOC cells, and to elucidate the underlying mechanism. Methods and results: It was found that MK8722 effectively inhibited the malignant biological behaviors of EOC cells. In vitro experiments showed that MK8722 targeted and decreased the lipid metabolic pathway-related fatty acid synthase (FASN) expression levels, causing the accumulation of lipid droplets. In addition, transmission electron microscopy revealed the presence of autophagosome-affected mitochondria. Western blotting confirmed that MK8722 plays a role in activating autophagy upstream (PI3K/AKT/mTOR) and inhibiting autophagy downstream via FASN-dependent reprogramming of lipid metabolism. Plasmid transient transfection demonstrated that MK8722 suppressed late-stage autophagy by blocking autophagosome-lysosome fusion. Immunofluorescence and gene silencing revealed that this effect was achieved by inhibiting the interaction of FASN with the SNARE complexes STX17-SNP29-VAMP8. Furthermore, the antitumor effect of MK8722 was verified using a subcutaneous xenograft mouse model. Conclusion: The findings suggest that using MK8722 may be a new strategy for treating EOC, as it has the potential to be a new autophagy/mitophagy inhibitor. Its target of action, FASN, is a molecular crosstalk between lipid metabolism and autophagy, and exploration of the underlying mechanism of FASN may provide a new research direction.

In vitro anticancer effect of azithromycin targeting hypoxic lung cancer cells via the inhibition of mitophagy

Solid tumors are predisposed to hypoxia, which induces tumor progression, and causes resistance to treatment. Hypoxic tumor cells exploit auto- and mitophagy to facilitate metabolism and mitochondrial renewal. Azithromycin (AZM), a widely used macrolide, inhibits autophagy in cancer cells. The aim of the present study was to determine whether AZM targeted hypoxic cancer cells by inhibiting mitophagy. Lung cancer cell lines (A549, H1299 and NCI-H441) were cultured for up to 72 h under normoxic (20% O2) or hypoxic (0.3% O2) conditions in the presence or absence of AZM (≤25 µM), and the cell survival, autophagy flux and mitophagy flux were evaluated. AZM treatment reduced cell survival under hypoxic conditions, caused mitolysosome dysfunction with raised lysosomal pH and impaired the efficient removal of hypoxia-damaged mitochondria, eventually inducing apoptosis in the cancer cells. The cytotoxic effect of AZM under hypoxic conditions was abolished in mitochondria-deficient A549 cells (ρ° cells). The present study demonstrated that AZM reduced lung cancer cell survival under hypoxic conditions by interfering with the efficient removal of damaged mitochondria through mitophagy inhibition. Thus, AZM may be considered as a promising anticancer drug that targets the mitochondrial vulnerability of hypoxic lung cancer cells.

Evaluation of Beclin1 and mTOR genes and p62 protein expression in breast tumor tissues of Iranian patients

Autophagy is a cellular process that plays a major role in the fate of tumor cells. Understanding the role of autophagy in cancer therapy is a major challenge, particularly for breast cancer as the sole top cause of mortality among women. In this study, we evaluated the gene expression of mTOR and Beclin1 and the levels of p62 protein, in breast tumors and compared them to a control condition. To explore the role of autophagy in breast cancer, we acquired tumor biopsies from 41 new cases of breast cancer patients. We extracted total RNA from each biopsy and used real-time PCR to quantify Beclin1 and mTOR-specific RNA expression. In addition, we evaluated the expression of the p62 protein in paraffin-embedded tumor tissue using the immunohistochemistry technique. The data revealed an upregulation of Beclin1 and a downregulation of mTOR in tumor tissues compared to the control condition. The correlation between p62 expression and Beclin1/mTOR showed a negative and positive correlation, respectively, confirming autophagy activation in the tumor tissues. However, there was no correlation between autophagy markers and tumor size, grade and stage. The findings revealed that autophagy activation was found in breast tumor tissues, suggesting that autophagy can be a target for breast cancer therapy.

Small-molecule drugs of colorectal cancer: Current status and future directions

Colorectal cancer (CRC) is the third most commonly diagnosed cancer and the world's fourth most deadly cancer. CRC, as a genetic susceptible disease, faces significant challenges in optimizing prognosis through optimal drug treatment modalities. In recent decades, the development of innovative small-molecule drugs is expected to provide targeted interventions that accurately address the different molecular characteristics of CRC. Although the clinical application of single-target drugs is limited by the heterogeneity and high metastasis of CRC, novel small-molecule drug treatment strategies such as dual/multiple-target drugs, drug repurposing, and combination therapies can help overcome these challenges and provide new insights for improving CRC treatment. In this review, we focus on the current status of a range of small molecule drugs that are being considered for CRC therapy, including single-target drugs, dual/multiple-target drugs, drug repurposing and combination strategies, which will pave the way for targeting CRC vulnerabilities with small-molecule drugs in future personalized treatment.

Ivermectin as a potential therapeutic strategy for glioma

Ivermectin (IVM), a semi-synthetic macrolide parasiticide, has demonstrated considerable effectiveness in combating internal and external parasites, particularly nematodes and arthropods. Its remarkable ability to control parasites has earned it significant recognition, culminating in Satoshi Omura and William C. Campbell's receipt of the 2015 Nobel Prize in Physiology or Medicine for their contributions to the development of IVM. In recent years, investigations have revealed that IVM possesses antitumor properties. It can suppress the growth of various cancer cells, including glioma, through a multitude of mechanisms such as selective targeting of tumor-specific proteins, inducing programmed cell death, and modulation of tumor-related signaling pathways. Hence, IVM holds tremendous potential as a novel anticancer drug. This review seeks to provide an overview of the underlying mechanisms that enable IVM's capacity to suppress glioma. Furthermore, it aims to elucidate the challenges and prospects associated with utilizing IVM as a new anticancer agent.

Targeting DGAT1 inhibits prostate cancer cells growth by inducing autophagy flux blockage via oxidative stress

Impaired macroautophagy/autophagy flux has been implicated in the treatment of prostate cancer (PCa). However, the mechanism underlying autophagy dysregulation in PCa remains unknown. In the current study, we investigated the role of diacylglycerol acyltransferases 1 (DGAT1) and its potential effects on cellular energy homeostasis and autophagy flux in PCa. The results of immunohistochemical staining suggested that DGAT1 expression was positively corrected with tumor stage and node metastasis, indicating DGAT1 is an important factor involved in the development and progression of PCa. Furthermore, targeting DGAT1 remarkably inhibited cell proliferation in vitro and suppressed PCa growth in xenograft models by triggering severe oxidative stress and subsequently autophagy flux blockage. Mechanically, DGAT1 promoted PCa progression by maintaining cellular energy homeostasis, preserving mitochondrial function, protecting against reactive oxygen species, and subsequently promoting autophagy flux via regulating lipid droplet formation. Moreover, we found that fenofibrate exhibits as an upstream regulator of DGAT1. Fenofibrate performed its anti-PCa effect involved the aforementioned mechanisms, and partially dependent on the regulation of DGAT1. Collectively. These findings indicate that DGAT1 regulates PCa lipid droplets formation and is essential for PCa progression. Targeting DGAT1 might be a promising method to control the development and progression of PCa. Schematic representation of DGAT1 affects autophagy flux by regulating lipid homeostasis and maintaining mitochondrial function in prostate cancer (PCa). PCa is characterized up-regulation of DGAT1, leading to the translocation of free fatty acids into lipid droplets, thereby preventing PCa cell from lipotoxicity. Inhibition of DGAT1 suppresses growth of PCa by inducing oxidative stress and subsequently autophagy flux blockage. Further, the current results revealed that fenofibrate exhibits as an upstream regulator of DGAT1, and fenofibrate plays an anti-PCa role partially dependent on the regulation of DGAT1, suggesting a potential therapeutic approach to ameliorate this refractory tumor.

HPV E6/E7: insights into their regulatory role and mechanism in signaling pathways in HPV-associated tumor

Human papillomavirus (HPV) is a class of envelope-free double-stranded DNA virus. HPV infection has been strongly associated with the development of many malignancies, such as cervical, anal and oral cancers. The viral oncoproteins E6 and E7 perform central roles on HPV-induced carcinogenic processes. During tumor development, it usually goes along with the activation of abnormal signaling pathways. E6 and E7 induces changes in cell cycle, proliferation, invasion, metastasis and other biological behaviors by affecting downstream tumor-related signaling pathways, thus promoting malignant transformation of cells and ultimately leading to tumorigenesis and progression. Here, we summarized that E6 and E7 proteins promote HPV-associated tumorigenesis and development by regulating the activation of various tumor-related signaling pathways, for example, the Wnt/β-catenin, PI3K/Akt, and NF-kB signaling pathway. We also discussed the importance of HPV-encoded E6 and E7 and their regulated tumor-related signaling pathways for the diagnosis and effective treatment of HPV-associated tumors.

Ezurpimtrostat, A Palmitoyl-Protein Thioesterase-1 Inhibitor, Combined with PD-1 Inhibition Provides CD8+ Lymphocyte Repopulation in Hepatocellular Carcinoma

BACKGROUND

Palmitoyl-protein thioesterase-1 (PPT1) is a clinical stage druggable target for inhibiting autophagy in cancer.

OBJECTIVE

We aimed to determine the cellular and molecular activity of targeting PPT1 using ezurpimtrostat, in combination with an anti-PD-1 antibody.

METHODS

In this study we used a transgenic immunocompetent mouse model of hepatocellular carcinoma.

RESULTS

Herein, we revealed that inhibition of PPT1 using ezurpimtrostat decreased the liver tumor burden in a mouse model of hepatocellular carcinoma by inducing the penetration of lymphocytes into tumors when combined with anti-programmed death-1 (PD-1). Inhibition of PPT1 potentiates the effects of anti-PD-1 immunotherapy by increasing the expression of major histocompatibility complex (MHC)-I at the surface of liver cancer cells and modulates immunity through recolonization and activation of cytotoxic CD8+ lymphocytes.

CONCLUSIONS

Ezurpimtrostat turns cold tumors into hot tumors and, thus, could improve T cell-mediated immunotherapies in liver cancer.

Tamoxifen Activates Transcription Factor EB and Triggers Protective Autophagy in Breast Cancer Cells by Inducing Lysosomal Calcium Release: A Gateway to the Onset of Endocrine Resistance

Among the several mechanisms accounting for endocrine resistance in breast cancer, autophagy has emerged as an important player. Previous reports have evidenced that tamoxifen (Tam) induces autophagy and activates transcription factor EB (TFEB), which regulates the expression of genes controlling autophagy and lysosomal biogenesis. However, the mechanisms by which this occurs have not been elucidated as yet. This investigation aims at dissecting how TFEB is activated and contributes to Tam resistance in luminal A breast cancer cells. TFEB was overexpressed and prominently nuclear in Tam-resistant MCF7 cells (MCF7-TamR) compared with their parental counterpart, and this was not dependent on alterations of its nucleo-cytoplasmic shuttling. Tam promoted the release of lysosomal Ca2+ through the major transient receptor potential cation channel mucolipin subfamily member 1 (TRPML1) and two-pore channels (TPCs), which caused the nuclear translocation and activation of TFEB. Consistently, inhibiting lysosomal calcium release restored the susceptibility of MCF7-TamR cells to Tam. Our findings demonstrate that Tam drives the nuclear relocation and transcriptional activation of TFEB by triggering the release of Ca2+ from the acidic compartment, and they suggest that lysosomal Ca2+ channels may represent new druggable targets to counteract the onset of autophagy-mediated endocrine resistance in luminal A breast cancer cells.

Personalization of Therapy in High-Grade Serous Tubo-Ovarian Cancer-The Possibility or the Necessity?

High-grade serous tubo-ovarian cancer (HGSTOC) is the most lethal tumor of the female genital tract. The foregoing therapy consists of cytoreduction followed by standard platinum/taxane chemotherapy; alternatively, for primary unresectable tumors, neo-adjuvant platinum/taxane chemotherapy followed by delayed interval cytoreduction. In patients with suboptimal surgery or advanced disease, different forms of targeted therapy have been accepted or tested in clinical trials. Studies on HGSTOC discovered its genetic and proteomic heterogeneity, epigenetic regulation, and the role of the tumor microenvironment. These findings turned attention to the fact that there are several distinct primary tumor subtypes of HGSTOC and the unique biology of primary, metastatic, and recurrent tumors may result in a differential drug response. This results in both chemo-refractoriness of some primary tumors and, what is significantly more frequent and destructive, secondary chemo-resistance of metastatic and recurrent HGSTOC tumors. Treatment possibilities for platinum-resistant disease include several chemotherapeutics with moderate activity and different targeted drugs with difficult tolerable effects. Therefore, the question appears as to why different subtypes of ovarian cancer are predominantly treated based on the same therapeutic schemes and not in an individualized way, adjusted to the biology of a specific tumor subtype and temporal moment of the disease. The paper reviews the genomic, mutational, and epigenetic signatures of HGSTOC subtypes and the tumor microenvironment. The clinical trials on personalized therapy and the overall results of a new, comprehensive approach to personalized therapy for ovarian cancer have been presented and discussed.

Identifying the programmed cell death index of hepatocellular carcinoma for prognosis and therapy response improvement by machine learning: a bioinformatics analysis and experimental validation

Background

Despite advancements in hepatocellular carcinoma (HCC) treatments, the prognosis for patients remains suboptimal. Cumulative evidence suggests that programmed cell death (PCD) exerts crucial functions in HCC. PCD-related genes are potential predictors for prognosis and therapeutic responses.

Methods

A systematic analysis of 14 PCD modes was conducted to determine the correlation between PCD and HCC. A novel machine learning-based integrative framework was utilized to construct the PCD Index (PCDI) for prognosis and therapeutic response prediction. A comprehensive analysis of PCDI genes was performed, leveraging data including single-cell sequencing and proteomics. GBA was selected, and its functions were investigated in HCC cell lines by in vitro experiments.

Results

Two PCD clusters with different clinical and biological characteristics were identified in HCC. With the computational framework, the PCDI was constructed, demonstrating superior prognostic predictive efficacy and surpassing previously published prognostic models. An efficient clinical nomogram based on PCDI and clinicopathological factors was then developed. PCDI was intimately associated with immunological attributes, and PCDI could efficaciously predict immunotherapy response. Additionally, the PCDI could predict the chemotherapy sensitivity of HCC patients. A multilevel panorama of PCDI genes confirmed its stability and credibility. Finally, the knockdown of GBA could suppress both the proliferative and invasive capacities of HCC cells.

Conclusion

This study systematically elucidated the association between PCD and HCC. A robust PCDI was constructed for prognosis and therapy response prediction, which would facilitate clinical management and personalized therapy for HCC.

Targeting the RAS/RAF/MAPK pathway for cancer therapy: from mechanism to clinical studies

Metastatic dissemination of solid tumors, a leading cause of cancer-related mortality, underscores the urgent need for enhanced insights into the molecular and cellular mechanisms underlying metastasis, chemoresistance, and the mechanistic backgrounds of individuals whose cancers are prone to migration. The most prevalent signaling cascade governed by multi-kinase inhibitors is the mitogen-activated protein kinase (MAPK) pathway, encompassing the RAS-RAF-MAPK kinase (MEK)-extracellular signal-related kinase (ERK) pathway. RAF kinase is a primary mediator of the MAPK pathway, responsible for the sequential activation of downstream targets, such as MEK and the transcription factor ERK, which control numerous cellular and physiological processes, including organism development, cell cycle control, cell proliferation and differentiation, cell survival, and death. Defects in this signaling cascade are associated with diseases such as cancer. RAF inhibitors (RAFi) combined with MEK blockers represent an FDA-approved therapeutic strategy for numerous RAF-mutant cancers, including melanoma, non-small cell lung carcinoma, and thyroid cancer. However, the development of therapy resistance by cancer cells remains an important barrier. Autophagy, an intracellular lysosome-dependent catabolic recycling process, plays a critical role in the development of RAFi resistance in cancer. Thus, targeting RAF and autophagy could be novel treatment strategies for RAF-mutant cancers. In this review, we delve deeper into the mechanistic insights surrounding RAF kinase signaling in tumorigenesis and RAFi-resistance. Furthermore, we explore and discuss the ongoing development of next-generation RAF inhibitors with enhanced therapeutic profiles. Additionally, this review sheds light on the functional interplay between RAF-targeted therapies and autophagy in cancer.

Construction and validation of a novel lysosomal signature for hepatocellular carcinoma prognosis, diagnosis, and therapeutic decision-making

Lysosomes is a well-recognized oncogenic driver and chemoresistance across variable cancer types, and has been associated with tumor invasiveness, metastasis, and poor prognosis. However, the significance of lysosomes in hepatocellular carcinoma (HCC) is not well understood. Lysosomes-related genes (LRGs) were downloaded from Genome Enrichment Analysis (GSEA) databases. Lysosome-related risk score (LRRS), including eight LRGs, was constructed via expression difference analysis (DEGs), univariate and LASSO-penalized Cox regression algorithm based on the TCGA cohort, while the ICGC cohort was obtained for signature validation. Based on GSE149614 Single-cell RNA sequencing data, model gene expression and liver tumor niche were further analyzed. Moreover, the functional enrichments, tumor microenvironment (TME), and genomic variation landscape between LRRSlow/LRRShigh subgroup were systematically investigated. A total of 15 Lysosomes-related differentially expressed genes (DELRGs) in HCC were detected, and then 10 prognosis DELRGs were screened out. Finally, the 8 optimal DELRGs (CLN3, GBA, CTSA, BSG, APLN, SORT1, ANXA2, and LAPTM4B) were selected to construct the LRRS prognosis signature of HCC. LRRS was considered as an independent prognostic factor and was associated with advanced clinicopathological features. LRRS also proved to be a potential marker for HCC diagnosis, especially for early-stage HCC. Then, a nomogram integrating the LRRS and clinical parameters was set up displaying great prognostic predictive performance. Moreover, patients with high LRRS showed higher tumor stemness, higher heterogeneity, and higher genomic alteration status than those in the low LRRS group and enriched in metabolism-related pathways, suggesting its underlying role in the progression and development of liver cancer. Meanwhile, the LRRS can affect the proportion of immunosuppressive cell infiltration, making it a vital immunosuppressive factor in the tumor microenvironment. Additionally, HCC patients with low LRRS were more sensitive to immunotherapy, while patients in the high LRRS group responded better to chemotherapy. Upon single-cell RNA sequencing, CLN3, GBA, and LAPTM4B were found to be specially expressed in hepatocytes, where they promoted cell progression. Finally, RT-qPCR and external datasets confirmed the mRNA expression levels of model genes. This study provided a direct links between LRRS signature and clinical characteristics, tumor microenvironment, and clinical drug-response, highlighting the critical role of lysosome in the development and treatment resistance of liver cancer, providing valuable insights into the prognosis prediction and treatment response of HCC, thereby providing valuable insights into prognostic prediction, early diagnosis, and therapeutic response of HCC.

Biogenic Zinc oxide nanoparticles from Celosia argentea: toward improved antioxidant, antibacterial, and anticancer activities

Biogenic Zinc oxide (ZnO) nanoparticles (NPs) were synthesized from Celosia argentea (C. argentea) plant extract. Structural analysis confirms the successful synthesis of biogenic zinc oxide NPs from C. argentea extract. The biogenic ZnO NPs have an average particle size of 21.55 ± 4.73 nm, a semispherical shape, and a specific surface area of about 50 m2/g. The biogenic ZnO NPs have a powerful radical scavenging activity (Ic50 = 91.24 mg/ml) comparable to ascorbic acid (ASC) as a standard (Ic50 = 14.37 mg/ml). The antibacterial efficacy was tested against gram-positive and gram-negative bacteria using an agar disc diffusion method. Gram-positive strains with biogenic ZnO NPs have a greater bactericidal impact than gram-negative strains in a concentration-dependent manner. Anticancer activity against Liver hepatocellular cells (HepG2) and Human umbilical vein endothelial cells (HUVEC) was evaluated using a [3-(4,5-dimethylthiazol-2-yl)-2,5diphenyl tetrazolium bromide] (MTT) assay. The results reflect the concentration-dependent cytotoxic effect of biogenic ZnO NPs against HepG2 cells even at low concentrations (Ic50 = 49.45 μg/ml) compared with doxorubicin (Ic50 = 14.67 μg/ml) and C. argentea extract (Ic50 = 112.24 μg/ml). The cell cycle and gene expression were analyzed to determine the potential anticancer mechanism. The flow cytometric analysis of the cell cycle revealed that biogenic ZnO NPs induce oxidative stress that activates the apoptotic genes NF-κB, CY-C, and P53, leading to cell death. The Celosia argentea improved the antioxidant, antibacterial, and anticancer activities of ZnO NPs without altering their structural properties. The effect of green synthesis on the bioactivity of biogenic ZnO NPs in vivo is recommended for future work.

Autophagy-mediated nanomaterials for tumor therapy

Autophagy is a lysosomal self-degradation pathway that plays an important protective role in maintaining intracellular environment. Deregulation of autophagy is related to several diseases, including cancer, infection, neurodegeneration, aging, and heart disease. In this review, we will summarize recent advances in autophagy-mediated nanomaterials for tumor therapy. Firstly, the autophagy signaling pathway for tumor therapy will be reviewed, including oxidative stress, mammalian target of rapamycin (mTOR) signaling and autophagy-associated genes pathway. Based on that, many autophagy-mediated nanomaterials have been developed and applied in tumor therapy. According to the different structure of nanomaterials, we will review and evaluate these autophagy-mediated nanomaterials' therapeutic efficacy and potential clinical application.

Cryptocaryone induces apoptosis in human hepatocellular carcinoma cells by inhibiting aerobic glycolysis through Akt and c-Src signaling pathways

Hepatocellular carcinoma (HCC) is the most common form of liver cancer, with the second highest mortality rate in all cancer. Energy reprogramming is one of the hallmarks of cancer, and emerging evidence showed that targeting glycolysis is a promising strategy for HCC treatment. Cryptocaryone has been shown to display promising anti-cancer activity against numerous types of cancer. Previous study also indicated that cryptocaryone induces cytotoxicity by inhibiting glucose transport in cancer cells, but the detailed mechanism still needs to be elucidated. Therefore, this study aimed to investigate the relationship between the anti-cancer effect and glycolytic metabolism of cryptocaryone in human HCC cells. In this study, we found that cryptocaryone potently induced growth inhibition by apoptotic cell death in HCC cells. Cryptocaryone also suppressed the ATP synthesis, lactate production and glycolytic capacity of HCC cells. Mechanistic investigations showed that phosphorylation of Akt and c-Src, as well as the expression of HK1 were impeded by cryptocaryone. Moreover, cryptocaryone markedly increased the expression level of transcription factor FoxO1. Importantly, clinical database analysis confirmed the negative correlation between HK1 and FoxO1. High expression levels of HK-1 were positively correlated with poorer survival in patients with HCCs. These results suggest that cryptocaryone may promote cell apoptosis by inhibiting FoxO1-mediated aerobic glycolysis through Akt and c-Src signaling cascades in human HCC cells. This is the first study to indicate that cryptocaryone exerts anti-cancer property against human HCC cells. Cryptocaryone is a potential natural product worthy of further development into a promising candidate for HCC treatment.

Blockade of DDR1/PYK2/ERK signaling suggesting SH2 superbinder as a novel autophagy inhibitor for pancreatic cancer

Pancreatic cancer is highly lethal, of which 90% is pancreatic ductal adenocarcinoma (PDAC), with a 5-year survival rate of less than 12%, lacking effective treatment options and late diagnosis. Furthermore, the tumors show an intense resistance to cytotoxic chemotherapies. As autophagy is elevated in PDAC, targeting the autophagic pathway is regarded as a promising strategy for cancer treatment. Immunofluorescence and transmission electron microscopy were utilized to assess the autophagic flux. Label-free quantitative phosphoproteomics was used to figure out critically altered tyrosine phosphorylation of the proteins. Tumor-bearing mice were used to validate that SH2 TrM-(Arg)9 restrained the growth of tumor cells. SH2 TrM-(Arg)9 inhibited collagen-induced autophagy via blocking the DDR1/PYK2/ERK signaling cascades. SH2 TrM-(Arg)9 improved the sensitivity of PANC-1/GEM cells to gemcitabine (GEM). Inhibition of autophagy by SH2 TrM-(Arg)9 may synergized with chemotherapy and robusted tumor suppression in pancreatic cancer xenografts. SH2 TrM-(Arg)9 could enter into PDAC cells and blockade autophagy through inhibiting DDR1/PYK2/ERK signaling and may be a new treatment strategy for targeted therapy of PDAC.

Emerging Relevance of Ghrelin in Programmed Cell Death and Its Application in Diseases

Ghrelin, comprising 28 amino acids, was initially discovered as a hormone that promotes growth hormones. The original focus was on the effects of ghrelin on controlling hunger and satiation. As the research further develops, the research scope of ghrelin has expanded to a wide range of systems and diseases. Nevertheless, the specific mechanisms remain incompletely understood. In recent years, substantial studies have demonstrated that ghrelin has anti-inflammatory, antioxidant, antiapoptotic, and other effects, which could affect the signaling pathways of various kinds of programmed cell death (PCD) in treating diseases. However, the regulatory mechanisms underlying the function of ghrelin in different kinds of PCD have not been thoroughly illuminated. This review describes the relationship between ghrelin and four kinds of PCD (apoptosis, necroptosis, autophagy, and pyroptosis) and then introduces the clinical applications based on the different features of ghrelin.

Targeted protein degradation in drug development: Recent advances and future challenges

Targeted protein degradation (TPD) has emerged as a promising therapeutic approach with potential advantages over traditional occupancy-based inhibitors in terms of dosing, side effects and targeting "undruggable" proteins. Targeted degraders can theoretically bind any nook or cranny of targeted proteins to drive degradation. This offers convenience versus the small-molecule inhibitors that must function in a well-defined pocket. The degradation process depends mainly on two cell self-destruction mechanisms, namely the ubiquitin-proteasome system and the lysosomal degradation pathway. Various TPD strategies (e.g., proteolytic-targeting chimeras, molecular glues, lysosome-targeting chimeras, and autophagy-targeting chimeras) have been developed. These approaches hold great potential for targeting dysregulated proteins, potentially offering therapeutic benefits. In this article, we systematically review the mechanisms of various TPD strategies, potential applications to drug discovery, and recent advances. We also discuss the benefits and challenges associated with these TPD strategies, aiming to provide insight into the targeting of dysregulated proteins and facilitate their clinical applications.

Hydroxychloroquine: Key therapeutic advances and emerging nanotechnological landscape for cancer mitigation

Hydroxychloroquine (HCQ) is a unique class of medications that has been widely utilized for the treatment of cancer. HCQ plays a dichotomous role by inhibiting autophagy induced by the tumor microenvironment (TME). Preclinical studies support the use of HCQ for anti-cancer therapy, especially in combination with conventional anti-cancer treatments since they sensitize tumor cells to drugs, potentiating the therapeutic activity. However, clinical evidence has suggested poor outcomes for HCQ due to various obstacles, including non-specific distribution, low aqueous solubility and low bioavailability at target sites, transport across tissue barriers, and retinal toxicity. These issues are addressable via the integration of HCQ with nanotechnology to produce HCQ-conjugated nanomedicines. This review aims to discuss the pharmacodynamic, pharmacokinetic and antitumor properties of HCQ. Furthermore, the antitumor performance of the nanoformulated HCQ is also reviewed thoroughly, aiming to serve as a guide for the HCQ-based enhanced treatment of cancers. The nanoencapsulation or nanoconjugation of HCQ with nanoassemblies appears to be a promising method for reducing the toxicity and improving the antitumor efficacy of HCQ.

WTAP regulates autophagy in colon cancer cells by inhibiting FLNA through N6-methyladenosine

Our study investigated the role of WTAP in colon cancer. We employed experiments including m6A dot blot hybridization, methylated RNA immunoprecipitation, dual-luciferase, and RNA immunoprecipitation to investigate the regulatory mechanism of WTAP. Western blot was performed to analyze the expression of WTAP, FLNA and autophagy-related proteins in cells. Our results confirmed the up-regulation of WTAP in colon cancer and its promoting effect on proliferation and inhibiting effect on apoptosis. FLNA was the downstream gene of WTAP and WTAP-regulated m6A modification led to post-transcriptional repression of FLNA. The rescue experiments showed that WTAP/FLNA could inhibit autophagy. WTAP-mediated m6A modification was confirmed to be crucial in colon cancer development, providing new insights into colon cancer therapy.

Sensitivity of osteosarcoma cell lines to autophagy inhibition as determined by pharmacologic and genetic manipulation

Pharmacologic inhibition of autophagy can be achieved using lysosomotropic agents such as hydroxychloroquine (HCQ) that interfere with fusion of the autophagosome to the lysosome thus preventing completion of the recycling process. The goal of the present study is to determine the sensitivity of eight canine (cOSA) and four human (hOSA) osteosarcoma tumour cell lines to antiproliferative and cytotoxic effects of lysosomal autophagy inhibitors, and to compare these results to the autophagy-dependence measured using a CRISPR/Cas9 live-cell imaging assay in OSA and other tumour cell lines. Antiproliferative and cytotoxic response to HCQ and Lys05 was determined using live cell imaging and YOYO-1 staining. CRISPR/Cas9 live cell imaging screen was done using species specific guide RNA's and transfection of reagents into cells. Response to autophagy core genes was compared to response to an essential (PCNA) and non-essential (FOXO3A) gene. cOSA and hOSA cell lines showed similar antiproliferative and cytotoxic responses to HCQ and Lys05 with median lethal dose (Dm ) values ranging from 4.6-15.8 μM and 2.1-5.1 μM for measures of anti-proliferative response, respectively. A relationship was observed between antiproliferative responses to HCQ and Lys05 and VPS34 CRISPR score with Dm values correlating with VPS34 response (r = 0.968 and 0.887) in a species independent manner. The results show that a subset of cOSA and hOSA cell lines are autophagy-dependent and sensitive to HCQ at pharmacologically-relevant exposures.

Hydroquinone-selected chronic myelogenous leukemia cells are sensitive to chloroquine-induced cytotoxicity via MCL1 suppression and glycolysis inhibition

Previous studies have provided evidence that repeated exposure to the benzene metabolite hydroquinone (HQ) induces malignant transformation and increases basal autophagy in the chronic myeloid leukemia (CML) cell line K562. This study explored the cytotoxicity of the autophagy inhibitor chloroquine (CQ) on parental and HQ-selected K562 (K562/HQ) cells. CQ triggered apoptosis in these cells independently of inhibiting autophagic flux; however, in K562/HQ cells, CQ-induced cytotoxicity was higher than in K562 cells. Mechanistically, CQ-induced NOXA upregulation led to MCL1 downregulation and mitochondrial depolarization in K562/HQ cells. MCL1 overexpression or NOXA silencing attenuated CQ-mediated cytotoxicity in K562/HQ cells. CQ triggered ERK inactivation to increase Sp1, NFκB, and p300 expression, and co-assembly of Sp1, NFκB, and p300 in the miR-29a promoter region coordinately upregulated miR-29a transcription. CQ-induced miR-29a expression destabilized tristetraprolin (TTP) mRNA, which in turn reduced TTP-mediated NOXA mRNA decay, thereby increasing NOXA protein expression. A similar mechanism explained the CQ-induced downregulation of MCL1 in K562 cells. K562/HQ cells relied more on glycolysis for ATP production than K562 cells, whereas inhibition of glycolysis by CQ was greater in K562/HQ cells than in K562 cells. Likewise, CQ-induced MCL1 suppression and glycolysis inhibition resulted in higher cytotoxicity in CML KU812/HQ cells than in KU812 cells. Taken together, our data confirm that CQ inhibits MCL1 expression through the ERK/miR-29a/TTP/NOXA pathway, and that inhibition of glycolysis is positively correlated to higher cytotoxicity of CQ on HQ-selected CML cells.

Growth or death? Control of cell destiny by mTOR and autophagy pathways

One of the central regulators of cell growth, proliferation, and metabolism is the mammalian target of rapamycin, mTOR, which exists in two structurally and functionally different complexes: mTORC1 and mTORC2; unlike m TORC2, mTORC1 is activated in response to the sufficiency of nutrients and is inhibited by rapamycin. mTOR complexes have critical roles not only in protein synthesis, gene transcription regulation, proliferation, tumor metabolism, but also in the regulation of the programmed cell death mechanisms such as autophagy and apoptosis. Autophagy is a conserved catabolic mechanism in which damaged molecules are recycled in response to nutrient starvation. Emerging evidence indicates that the mTOR signaling pathway is frequently activated in tumors. In addition, dysregulation of autophagy was associated with the development of a variety of human diseases, such as cancer and aging. Since mTOR can inhibit the induction of the autophagic process from the early stages of autophagosome formation to the late stage of lysosome degradation, the use of mTOR inhibitors to regulate autophagy could be considered a potential therapeutic option. The present review sheds light on the mTOR and autophagy signaling pathways and the mechanisms of regulation of mTOR-autophagy.

TLR9 regulates the autophagy-lysosome pathway to promote dendritic cell maturation and activation by activating the TRAF6-cGAS-STING pathway

Dysregulated maturation and activation of dendritic cells (DCs) play a significant role in the progression of systemic lupus erythematosus (SLE). The autophagy-lysosome pathway has been identified as a potential mechanism to inhibit DC activation and maturation, but its precise workings remain unclear. We investigated the role and regulatory mechanism of TLR9 in modulating the autophagy-lysosome pathway and DCs activation. The mRNA and protein expressions were assessed using qRT-PCR and/or western blot. NZBW/F1 mice was used to construct a lupus nephritis (LN) model in vivo. Cell apoptosis was analyzed by TUNEL staining. Flow cytometry was adopted to analyze DCs surface markers. Lyso-tracker red staining was employed to analyze lysosome acidification. Levels of anti-dsDNA, cytokines, C3, C4, urine protein and urine creatinine were examined by ELISA. The results showed that TLR9 was markedly increased in SLE patients, and its expression was positively correlated with SLEDAI scores and dsDNA level. Conversely, TLR9 expression showed a negative correlation with C3 and C4 levels. Loss-of function experiments demonstrated that TLR9 depletion exerted a substantial inhibition of renal injury, inflammation, and DCs numbers. Additionally, upregulation of TLR9 promoted DCs maturation and activation through activation of autophagy and lysosome acidification. Further investigation revealed that TLR9 targeted TRAF6 to activate the cGAS-STING pathway. Rescue experiments revealed that inactivation of the cGAS/STING signaling pathway could reverse the promoting effects of TLR9 upregulation on DCs maturation, activation, and autophagy-lysosome pathway. Overall, our findings suggested that TLR9 activated the autophagy-lysosome pathway to promote DCs maturation and activation by activating TRAF6-cGAS-STING pathway, thereby promoting SLE progression.

MIOX inhibits autophagy to regulate the ROS -driven inhibition of STAT3/c-Myc-mediated epithelial-mesenchymal transition in clear cell renal cell carcinoma

The specific mechanism of clear cell renal cell carcinoma (ccRCC) progression, a pathological type that accounts for the highest proportion of RCC, remains unclear. In this study, bioinformatics analysis of scRNA-seq dataset in ccRCC revealed that MIOX was a gene specifically down-regulated in tumor epithelial cells of ccRCC. Analysis of the TCGA database further validated the association between decreased MIOX mRNA levels and ccRCC malignant phenotype and poor prognosis. Immunohistochemistry indicated the down-regulation of MIOX in ccRCC tissues compared to paired adjacent renal tissues, with further down-regulation of MIOX in the primary tumors of patients with primary metastasis compared to those without metastasis. Also, patients with low expression of MIOX showed shorter metastasis-free survival (MFS) compared to those with high MIOX expression. In vitro results showed that overexpression of MIOX in ccRCC cells inhibited the proliferation, migration and invasion and promoted apoptosis. Mechanistically, up-regulation of MIOX inhibited autophagy to elevate the levels of ROS, and thus suppressed STAT3/c-Myc-mediated epithelial-mesenchymal transition in ccRCC cells. In vivo data further confirmed that increased MIOX expression suppressed the growth and proliferation of RCC cells and reduced the ability of RCC cells to form metastases in the lung. This study demonstrates that MIOX is an important regulatory molecule of ccRCC, which is conducive to understanding the potential molecular mechanism of ccRCC progression.

Targeting autophagy with SAR405 alleviates doxorubicin-induced cardiotoxicity

Anthracycline antitumor agents, such as doxorubicin (DOX), are effective in the treatment of solid tumors and hematological malignancies, but anthracycline-induced cardiotoxicity (AIC) limits their application as chemotherapeutics. Dexrazoxane (DEX) has been adopted to prevent AIC. Using a chronic AIC mouse model, we demonstrated that DEX is insufficient to reverse DOX-induced cardiotoxicity. Although therapies targeting autophagy have been explored to prevent AIC, but whether novel autophagy inhibitors could alleviate or prevent AIC in clinically relevant models needs further investigation. Here, we show that genetic ablation of Atg7, a key regulator in the early phase of autophagy, protected mice against AIC. We further demonstrated that SAR405, a novel autophagy inhibitor, attenuated DOX-induced cytotoxicity. Intriguingly, the combination of DEX and SAR405 protected cells against DOX-induced cardiotoxicity in vivo. Using the cardiomyocyte cell lines AC16 and H9c2, we determined that autophagy was initiated during AIC. Our results suggest that inhibition of autophagy at its early phase with SAR405 combined with DEX represents an effective therapeutic strategy to prevent AIC.

Long non-coding RNAs: controversial roles in drug resistance of solid tumors mediated by autophagy

Current genome-wide studies have indicated that a great number of long non-coding RNAs (lncRNAs) are transcribed from the human genome and appeared as crucial regulators in a variety of cellular processes. Many studies have displayed a significant function of lncRNAs in the regulation of autophagy. Autophagy is a macromolecular procedure in cells in which intracellular substrates and damaged organelles are broken down and recycled to relieve cell stress resulting from nutritional deprivation, irradiation, hypoxia, and cytotoxic agents. Autophagy can be a double-edged sword and play either a protective or a damaging role in cells depending on its activation status and other cellular situations, and its dysregulation is related to tumorigenesis in various solid tumors. Autophagy induced by various therapies has been shown as a unique mechanism of resistance to anti-cancer drugs. Growing evidence is showing the important role of lncRNAs in modulating drug resistance via the regulation of autophagy in a variety of cancers. The role of lncRNAs in drug resistance of cancers is controversial; they may promote or suppress drug resistance via either activation or inhibition of autophagy. Mechanisms by which lncRNAs regulate autophagy to affect drug resistance are different, mainly mediated by the negative regulation of micro RNAs. In this review, we summarize recent studies that investigated the role of lncRNAs/autophagy axis in drug resistance of different types of solid tumors.

Multi-omics approaches identify novel prognostic biomarkers of autophagy in uveal melanoma

PURPOSE

Uveal melanoma (UVM) is a rare yet malignant ocular tumor that metastases in approximately half of all patients, with the majority of those developing metastasis typically succumbing to the disease within a year. Hitherto, no effective treatment for UVM has been identified. Autophagy is a cellular mechanism that has been suggested as an emerging regulatory process for cancer-targeted therapy. Thus, identifying novel prognostic biomarkers of autophagy may help improve future treatment.

METHODS

Consensus clustering and similarity network fusion approaches were performed for classifying UVM patient subgroups. Weighted correlation network analysis was performed for gene module screening and network construction. Gene set variation analysis was used to evaluate the autophagy activity of the UVM subgroups. Kaplan-Meier survival curves (Log-rank test) were performed to analyze patient prognosis. Gene set cancer analysis was used to estimate the level of immune cell infiltration.

RESULTS

In this study, we employed multi-omics approaches to classify UVM patient subgroups by molecular and clinical characteristics, ultimately identifying HTR2B, EEF1A2, FEZ1, GRID1, HAP1, and SPHK1 as potential prognostic biomarkers of autophagy in UVM. High expression levels of these markers were associated with poorer patient prognosis and led to reshaping the tumor microenvironment (TME) that promotes tumor progression.

CONCLUSION

We identified six novel potential prognostic biomarkers in UVM, all of which are associated with autophagy and TME. These findings will shed new light on UVM therapy with inhibitors targeting these biomarkers expected to regulate autophagy and reshape the TME, significantly improving UVM treatment outcomes.

Ubiquitin-specific protease 22 promotes tumorigenesis and progression by an FKBP12/mTORC1/autophagy positive feedback loop in hepatocellular carcinoma

Ubiquitin-specific protease 22 (USP22) has been identified as a potential marker for cancer stem cells in hepatocellular carcinoma (HCC). It can promote HCC stemness, which is considered a driver of tumorigenesis. Here, we sought to determine the role of USP22 in tumorigenesis, elucidate its underlying mechanism, and explore its therapeutic significance in HCC. As a result, we found that tissue-specific Usp22 overexpression accelerated tumorigenesis, whereas Usp22 ablation decelerated it in a c-Myc/NRasGV12-induced HCC mouse model and that the mammalian target of rapamycin complex 1 (mTORC1) pathway was activated downstream. USP22 overexpression resulted in increased tumorigenic properties that were reversed by rapamycin in vitro and in vivo. In addition, USP22 activated mTORC1 by deubiquitinating FK506-binding protein 12 (FKBP12) and activated mTORC1, in turn, further stabilizing USP22 by inhibiting autophagic degradation. Clinically, HCC patients with high USP22 expression tend to benefit from mTOR inhibitors after liver transplantation (LT). Our results revealed that USP22 promoted tumorigenesis and progression via an FKBP12/mTORC1/autophagy positive feedback loop in HCC. Clinically, USP22 may be an effective biomarker for selecting eligible recipients with HCC for anti-mTOR-based therapy after LT.

MiR-526b-3p enhances sensitivity of head and neck squamous cell carcinoma cells to radiotherapy via suppressing exosomal LAMP3-mediated autophagy

Lysosomal associated membrane protein 3 (LAMP3) has been reported to be a tumour promoter in multiple cancer types by modulating tumour cell autophagy. However, the potential mechanism of LAMP3 in radio-resistance of head and neck squamous cell carcinoma (HNSCC) remains unknown. Therefore, our current study aims to detect the impacts of LAMP3 on the resistance of HNSCC cells to radiotherapy and meanwhile explore its functional mechanism. Through RT-Qpcr examination, LAMP3 expression was identified to be expressed at a significantly high level in irradiation-resistant HNSCC cell lines compared with irradiation-sensitive HNSCC cell lines. Functional assays including CCK-8, colony formation and Transwell assays demonstrated that LAMP3 enhanced the radio-resistance through inducing autophagy to promote HNSCC cell growth. Furthermore, irradiation-resistant HNSCC cells could transfer exosomal LAMP3 to elevate LAMP3 expression in irradiation-sensitive HNSCC cells. Mechanistically, microRNA (miRNA) miR-526b-3p could inhibit LAMP3 expression so as to strengthen sensitivity of HNSCC cells to radiotherapy. In a word, exosomal LAMP3 expression promoted radioresistance of HNSCC cells via inducing autophagy, while this effect could be suppressed by miR-526b-3p in a targeted manner.

Enhancing autophagy leads to increased cell death in radiation-treated cervical cancer cells

This study was carried out to determine the effect of autophagy modulation in radiation treatment of cervical cancer cells. HeLa and CaSki cells were irradiated with γ-rays (2 Gy/min) after treatment with an autophagy inducer (rapamycin) and inhibitor (3-MA). Expression of LC3 and cell death in two cell preparations were examined. In addition, expression of Caspase-3 and PARP were examined after radiation alone and with autophagy inhibitor treatment. A notable increment of LC3 expression was detected after radiation in both cell lines. Cell viability was observed to decrease in 3-MA-treated cells compared to radiation alone, and even further in rapamycin-treated cells. Apoptosis was confirmed to occur later than autophagy in radiation treatment, and inhibition of autophagy derived a decrease in apoptosis. In conclusion, radiation-induced autophagy may be regulated by modulators, and autophagy augmentation yields an increase in cervical cancer cell death under radiation.Impact statementWhat is already known on this subject? Autophagy is known to contribute both to tumour cell survival and death against radiation therapy. The effect of induction or inhibition of radiation-induced autophagy on cervical cancer cell death is not clear.What the results of this study add? Cell viability was observed to decrease in 3-MA-treated cells compared to radiation alone, and even further in rapamycin-treated cells. Apoptosis occurred later than autophagy in radiation treatment, and inhibition of autophagy derived a decrease in apoptosis.What the implications are of these findings for clinical practice and/or further research? Our results suggest that radiation-induced autophagy may be regulated by modulators, and autophagy augmentation yields an increase in cervical cancer cell death under radiation.

The role of mitochondrial dynamics in disease

Mitochondria are multifaceted and dynamic organelles regulating various important cellular processes from signal transduction to determining cell fate. As dynamic properties of mitochondria, fusion and fission accompanied with mitophagy, undergo constant changes in number and morphology to sustain mitochondrial homeostasis in response to cell context changes. Thus, the dysregulation of mitochondrial dynamics and mitophagy is unsurprisingly related with various diseases, but the unclear underlying mechanism hinders their clinical application. In this review, we summarize the recent developments in the molecular mechanism of mitochondrial dynamics and mitophagy, particularly the different roles of key components in mitochondrial dynamics in different context. We also summarize the roles of mitochondrial dynamics and target treatment in diseases related to the cardiovascular system, nervous system, respiratory system, and tumor cell metabolism demanding high-energy. In these diseases, it is common that excessive mitochondrial fission is dominant and accompanied by impaired fusion and mitophagy. But there have been many conflicting findings about them recently, which are specifically highlighted in this view. We look forward that these findings will help broaden our understanding of the roles of the mitochondrial dynamics in diseases and will be beneficial to the discovery of novel selective therapeutic targets.

Periplocin suppresses the growth of colorectal cancer cells by triggering LGALS3 (galectin 3)-mediated lysophagy

Colorectal cancer (CRC) is one of the most common malignancies worldwide and remains a major clinical challenge. Periplocin, a major bioactive component of the traditional Chinese herb Cortex periplocae, has recently been reported to be a potential anticancer drug. However, the mechanism of action is poorly understood. Here, we show that periplocin exhibits promising anticancer activity against CRC both in vitro and in vivo. Mechanistically, periplocin promotes lysosomal damage and induces apoptosis in CRC cells. Notably, periplocin upregulates LGALS3 (galectin 3) by binding and preventing LGALS3 from Lys210 ubiquitination-mediated proteasomal degradation, leading to the induction of excessive lysophagy and resultant exacerbation of lysosomal damage. Inhibition of LGALS3-mediated lysophagy attenuates periplocin-induced lysosomal damage and growth inhibition in CRC cells, suggesting a critical role of lysophagy in the anticancer effects of periplocin. Taken together, our results reveal a novel link between periplocin and the lysophagy machinery, and indicate periplocin as a potential therapeutic option for the treatment of CRC.Abbreviations: 3-MA: 3-methyladenine; ACACA/ACC1: acetyl-CoA carboxylase alpha; AMPK: adenosine monophosphate-activated protein kinase; AO: Acridine orange; ATG5: autophagy related 5; ATG7: autophagy related 7; CALM: calmodulin; CHX: cycloheximide; CRC: colorectal cancer; CQ: chloroquine; CTSB: cathepsin B; CTSD: cathepsin D; ESCRT: endosomal sorting complex required for transport; LAMP1: lysosomal associated membrane protein 1; LMP: lysosomal membrane permeabilization; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MCOLN1/TRPML1: mucolipin TRP cation channel 1; MKI67/Ki-67: marker of proliferation Ki-67; MTOR: mechanistic target of rapamycin kinase; P2RX4/P2X4: purinergic receptor P2X 4; PARP1/PARP: poly(ADP-ribose) polymerase 1; PRKAA/AMPKα: protein kinase AMP-activated catalytic subunit alpha; SQSTM1/p62: sequestosome 1; TFEB: transcription factor EB; TRIM16: tripartite motif containing 16.

The role of autophagy in hypoxia-induced radioresistance

Radiotherapy is a widely used treatment modality against cancer, and although survival rates are increasing, radioresistant properties of tumours remain a significant barrier for curative treatment. Tumour hypoxia is one of the main contributors to radioresistance and is common in most solid tumours. Hypoxia is responsible for many molecular changes within the cell which helps tumours to survive under such challenging conditions. These hypoxia-induced molecular changes are predominantly coordinated by the hypoxia inducible factor (HIF) and have been linked with the ability to confer resistance to radiation-induced cell death. To overcome this obstacle research has been directed towards autophagy, a cellular process involved in self degradation and recycling of macromolecules, as HIF plays a large role in its coordination under hypoxic conditions. The role that autophagy has following radiotherapy treatment is conflicted with evidence of both cytoprotective and cytotoxic effects. This literature review aims to explore the intricate relationship between radiotherapy, hypoxia, and autophagy in the context of cancer treatment. It provides valuable insights into the potential of targeting autophagy as a therapeutic strategy to improve the response of hypoxic tumours to radiotherapy.

Combinatorial Treatment with PARP and MAPK Inhibitors Overcomes Phenotype Switch-Driven Drug Resistance in Advanced Melanoma

Metastatic melanoma is either intrinsically resistant or rapidly acquires resistance to targeted therapy treatments, such as MAPK inhibitors (MAPKi). A leading cause of resistance to targeted therapy is a dynamic transition of melanoma cells from a proliferative to a highly invasive state, a phenomenon called phenotype switching. Mechanisms regulating phenotype switching represent potential targets for improving treatment of patients with melanoma. Using a drug screen targeting chromatin regulators in patient-derived three-dimensional MAPKi-resistant melanoma cell cultures, we discovered that PARP inhibitors (PARPi) restore sensitivity to MAPKis, independent of DNA damage repair pathways. Integrated transcriptomic, proteomic, and epigenomic analyses demonstrated that PARPis induce lysosomal autophagic cell death, accompanied by enhanced mitochondrial lipid metabolism that ultimately increases antigen presentation and sensitivity to T-cell cytotoxicity. Moreover, transcriptomic and epigenetic rearrangements induced by PARP inhibition reversed epithelial-mesenchymal transition-like phenotype switching, which redirected melanoma cells toward a proliferative and MAPKi-sensitive state. The combination of PARP and MAPKis synergistically induced cancer cell death both in vitro and in vivo in patient-derived xenograft models. Therefore, this study provides a scientific rationale for treating patients with melanoma with PARPis in combination with MAPKis to abrogate acquired therapy resistance.

SIGNIFICANCE

PARP inhibitors can overcome resistance to MAPK inhibitors by activating autophagic cell death and reversing phenotype switching, suggesting that this synergistic combination could help improve the prognosis of patients with melanoma.

Recognition and combination of multiple cell-death features showed good predictive value in lung adenocarcinoma

BACKGROUND

Cell death is a key regulatory process in organisms and its study has become increasingly important in the field of cancer. While prior research has primarily centered on the individual pathways of cell death in cancer, there has been a lack of comprehensive investigation into the synergistic effects of multiple cell death pathways.

METHODS

Genes related to autophagy, apoptosis, necroptosis, pyroptosis, and cuproptosis was selected, and patients' data was collected from The Cancer Genome Atlas (TCGA)project. Cell death features were identified using principal component analysis and combined to create a composite score. A scalable prediction model was then created using LASSO regression after a thorough assessment of the composite scores. The model was subsequently validated across multiple external datasets to establish its robustness and reliability.

RESULTS

The cell death features effectively represented the gene expression patterns in the samples. The composite score well predicted prognosis, clinical stage, mutation, tumor microenvironment, and immunotherapy effectiveness. The model built on composite scores accurately predicted prognosis and immunotherapy effectiveness across multiple datasets. GJB2 was identified as a potential biomarker.

CONCLUSION

Models based on multiple cell death pathways have significant predictive power for prognosis and immunotherapy effectiveness in lung adenocarcinoma. This highlights the synergistic role of multiple cell death pathways in cancer development and offers a new perspective for cancer research.