Tumor Autophagy Research Articles

T1/T2 Proportional Magnetic Resonance Nanoprobe Monitoring Tumor Autophagy during Chemotherapy.

Autophagy leads to cellular tolerance of the therapeutic pressure of chemotherapeutic drugs, resulting in treatment resistance. Therefore, the effective monitoring of the autophagy status of tumors in vivo and the regulating of the autophagy level are crucial for improving the efficacy of chemotherapy. In this work, we grafted nitroxide radicals onto the surface of iron oxide nanoparticles (Fe3O4 NPs) using dendrimer polymers, yielding Fe3O4-NO· NPs that are responsive to reactive oxygen species (ROS) and possess enhanced T1 and T2 signal capabilities in a magnetic resonance imaging (MRI) measurement. The ROS in tumor cells generated by autophagy quenches the nitroxide radicals, thereby weakening the T1 signal. In contrast, Fe3O4 NPs are unaffected by intracellular ROS, leading to a stable T2 signal. By comparing the intensity ratio of T1 to T2 in Fe3O4-NO· NPs, we can evaluate the in vivo autophagy status within tumors in real time. It also revealed that Fe3O4-NO· NPs loaded with doxorubicin (Dox) and combining the autophagy inhibitor exhibited high antitumor activity in cells and tumor-bearing mice. This system, which combines real-time monitoring of tumor cell autophagy with the delivery of chemotherapeutic drugs, provides an innovative and effective strategy for tumor treatment with potential clinical application prospects.

Sonocatalysis Regulates Tumor Autophagy for Enhanced Immunotherapy.

Immunotherapy stands as a groundbreaking strategy for cancer treatment, due to its ability to precisely and safely detect and eradicate tumors. However, the efficacy of immunotherapy is often limited by tumor autophagy, a natural defense mechanism that tumors exploit to resist immune attacks. Herein, we introduce a spatiotemporally controlled method to modulate tumor autophagy via sonocatalysis, aiming to improve immunotherapeutic outcomes. Specifically, we synthesized a tumor-targeting nanocatalyst based on a semiconductor heterojunction composed of Barium Titanate (BTO), Black Phosphorus (BP) integrated with Hyaluronic Acid (HA), referred to as BTO/BP-HA. Compared to traditional catalysts, the heterojunction structure enhances energy band bending and rapid electron-hole separation under ultrasonic stimulation, splitting water to generate H2. This promotes tumor cell apoptosis by inhibiting mitochondrial respiration and induces immunogenic cell death, triggering immune responses to eliminate tumor cells. However, the concurrent activation of autophagy mitigates the cytotoxic effectiveness of nanocatalysts. Within the nanocatalyst, BP undergoes lysosomal degradation to generate PO43-, which subsequently interacts with H+ to generate a conjugated acidic anion, increasing the lysosomal pH. This research ingeniously combines sonocatalysis with tumor autophagy, disrupting the activity of acidic hydrolases to inhibit autophagy, thereby enhancing the immune response and improving the effectiveness of immunotherapy.

LINC00941 is a diagnostic biomarker for lung adenocarcinoma and promotes tumorigenesis through cell autophagy.

Non-small cell lung cancer (NSCLC) is a lethal malignancy. There is mounting evidence indicating that lncRNAs are crucial players with dual roles as both biomarkers and regulators across various cancers. It was reported that LINC00941 plays a cancer-promoting role in NSCLC. However, its impact on tumour autophagy remains poorly understood. In this study, we developed a risk assessment model and identified an autophagy-related lncRNA LINC00941, which has independent predictive and early diagnostic potential. Using RT-qPCR analysis, we confirmed the upregulation of LINC00941 in tumour tissues and cell lines of human lung adenocarcinoma (LUAD). Functional assays, such as CCK8, colony formation and xenograft models, demonstrated the cancer-promoting activity of LINC00941 both invitro and invivo. Further analysis using Western blotting analysis, mRFP-GFP-LC3 double fluorescence lentivirus vector and transmission electron microscopy (TEM) confirmed that the knockdown of LINC00941 triggered autophagy. These results indicate that knockdown of LINC00941 induces autophagy and impairs the proliferation of LUAD. Therefore, we propose LINC00941 as an independent biomarker for early diagnosis as well as a therapeutic target in LUAD.

Bioinformatics Analysis of the Expression and Prognostic Value of PLAU Gene in Wilms' Tumor.

Autophagy and immunity play important roles in the growth of malignant tumors and are promising targets for tumor therapy. This study was conducted to identify differentially expressed immune genes related to autophagy in Wilms' tumor (WT) and analyze their correlation with the disease prognosis. The public data of WT and normal kidney tissues were downloaded from TCGA, ImmPort, and GeneCards databases to obtain differentially expressed immune genes associated with autophagy. Survival analysis, ROC curve, and clinical relevance filtering were used to screen the key gene plasminogen activator urokinase (PLAU). The univariable and multivariable Cox regression model analyses were used to analyze the prognostic factors of overall survival (OS) in patients with WT. Then, GO enrichment, KEGG pathway analysis and GSEA were used to enrich and analyze differentially expressed genes. The relationship between PLAU gene expression and tumor microenvironment and infiltration of immune cells was analyzed, as well as between the expression of PLAU and epigenetic modifications. PLAU gene expression was associated with survival and prognosis in WT patients and was an independent prognostic indicator of OS in patients. The GO, KEGG, and GSEA analysis results suggested that PLAU may be involved in RNA transcription and epithelial cell migration. High expression of PLAU was also associated with increased immune cell infiltration and a higher presence of antitumor immune cells. The low expression of PLAU in WT was related to DNA methylation and may be also co-regulated by miR-342-3p. PLAU can be used as an independent prognostic biomarker for WT. Low expression of PLAU is associated with poor prognosis in WT patients. Evidence on the prognostic value of PLAU gene and the pathways that may be associated with its expression is invaluable for the development of new therapies for WT.

Construction of a prognostic model for autophagy in Wilm's tumor.

Wilm's tumor (WT) is one of the most common childhood urological tumors, ranking second in the incidence of pediatric abdominal tumors. The development of WT is associated with various factors, and the correlation with autophagy is currently unclear. To develop a new prognostic model of autophagy-related genes (ATG) for WT. Using the Therapeutically applicable research to generate effective treatments (TARGET) database to screen for differentially expressed ATGs in WT and normal tissues. ATGs were screened for prognostic relevance to WT using one-way and multifactorial Cox regression analyses and prognostic models were constructed. The risk score was calculated according to the model, and the predictive ability of the constructed model was analyzed using the ROC (receiver operating characteristic) curve to verify the significance of the model for the prognosis of WT. Sixty-eight differentially expressed ATGs were identified by univariate Cox regression analysis, and two critical prognostic ATGs (CXCR4 and ERBB2) were identified by multivariate Cox regression analysis. Patients were divided into high-risk and low-risk groups according to the differential expression of these two ATGs. Kaplan-Meier (KM) curves showed a significant difference in survival time between the two groups. The critical prognostic ATGs were combined with race, age, and stage in a multifactorial regression analysis, and the final prognostic model was produced as a line graph. The prognostic model of autophagy-related genes composed of the CXCR4 gene and ERBB2 gene has a specific predictive value for the prognosis of WT, and the present study provides a clear basis for future research on biomarkers and therapeutic targets.

Transformation of Ginsenosides by Lactiplantibacillus plantarum MB11 Fermentation: Minor Ginsenosides Conversion and Enhancement of Anti-Colorectal Cancer Activity.

The present study aimed to increase the content of minor ginsenosides and enhance the anti-colorectal cancer activity of ginsenosides via biotransformation by Lactiplantibacillus plantarum MB11 screened from fermented foods. A subcutaneous transplantation tumor model of murine colorectal cancer CT26 cells was established in mice to study the anticarcinogenic activities and mechanism of fermented total ginsenosides (FTGs). The results showed that L. plantarum MB11 fermentation increased the content of minor ginsenosides and decreased that of major ginsenosides. FTGs reduced the tumor weight and size compared with the model group. Immunofluorescence and TdT-mediated dUTP nick end labeling (TUNEL) analysis showed that FTGs significantly increase the number of caspase-3 cells in tumor tissue and induce cell apoptosis. Mechanically, FTGs activate AMPK/mTOR autophagy pathway and regulate JAK2/STAT3 and Bax/Bcl-2/caspase-3 apoptosis pathway. Overall, fermentation with L. plantarum MB11 enhanced minor ginsenosides in total ginsenosides, and FTGs induced subcutaneous transplantation tumor autophagy and apoptosis in mice.

Atg4B and Cathepsin B-Triggered in Situ Luciferin Formation for Precise Cancer Autophagy Bioluminescence Imaging.

Autophagy plays a crucial role in tumorigenesis and progression, but current approaches to visualize it in vivo show limited precision due to their single-analyte-responsive mode. Hence, by simultaneously employing dual autophagy enzymes Atg4B and cathepsin B to trigger the in situ formation of luciferin, we herein propose a strategy for precise autophagy bioluminescence imaging. An Atg4B-responsive peptide Ac-Thr-Phe-Gly-d-Cys (TFGC) and a cathepsin B-activatable compound Ac-Lys-Gly-Arg-Arg-CBT (KGRR-CBT) were rationally designed. During tumor autophagy, these two compounds were uptaken by cancer cells and cleaved by their corresponding enzymes to yield d-cysteine and 2-cyano-6-aminobenzothiazole, respectively, which underwent a CBT-Cys click reaction to yield d-aminoluciferin, turning the bioluminescence "on". The responsiveness of these two compounds toward the two enzymes was tested in vitro, and the ability to turn bioluminescence "on" was validated in living cancer cells and in vivo. We anticipate that our precise autophagy imaging strategy could be further applied for the diagnosis of autophagy-related diseases in the near future.

Tumor acidity-activatable macromolecule autophagy inhibitor and immune checkpoint blockade for robust treatment of prostate cancer.

Immune checkpoint blockade (ICB) antibody such as anti-PD-L1 (aPD-L1) activates cytotoxic T cells (CTLs) to combat cancer, but they showed poor efficacy in prostate cancer (PCa). Lysosome-dependent autophagy is utilized by cancer cells to degrade their MHC-I and to lower their vulnerability to TNF-α and CTLs. Lysosomal pH-sensitive polymeric nanoparticle as a drug delivery carrier may also be a novel autophagy inhibitor to boost immunotherapy, but such an important effect has not been investigated. Herein, we developed a unique tumor acidity-activatable macromolecular nanodrug (called P-PDL1-CP) with the poly(2-diisopropylaminoethyl methacrylate) (PDPA) core and the conjugations of both aPD-L1 and long-chain polyethylene glycol (PEG) coating. The PDPA core was demonstrated to disturb lysosome to block the autophagic flux, thus elevating the cancer cell's MHC-I expression and vulnerability to the TNF-α and CTLs. Long-chain PEG facilitated a good tumor accumulation of P-PDL1-CP nanodrug. Furthermore, P-PDL1-CP nanodrug inhibited tumor autophagy, which synergized with aPD-L1 to promote the tumor-infiltrating CTLs and DCs maturation, to elevate intratumoral TNF-α and IFN-γ levels, and to elicit an anti-tumor immune memory effect in mice for PCa growth inhibition with low side effects. This study verified the synergistic anti-PCa treatment between autophagy inhibition and PD-L1 blockade and meantime broadened the application of pH-sensitive macromolecular nanodrug. STATEMENT OF SIGNIFICANCE: A macromolecular nanodrug, comprising the PDPA core and the surface conjugation of both aPD-L1 antibodies and long-chain PEG coating via a tumor acidity-labile α-carboxy-dimethylmaleic anhydride amine bond, was developed. Tumoral acidity triggered the release of aPD-L1 for immunotherapy. Meantime, the charge switch of the remanent nanodrug enhanced the cancer cell uptake of PDPA, which disturbed the lysosomes to inhibit autophagy. This advanced nanodrug promoted the tumor-infiltrating CTLs and DCs maturation, elevated the intratumoral TNF-α and IFN-γ levels, and elicited the robust anti-tumor immune memory effect. This study demonstrated that the pH-sensitive PDPA macromolecule could serve as a carrier for the aPD-L1 delivery and as an efficient autophagy inhibitor to boost the immunotherapy of prostate cancer.

A “bulldozer” driven by anoxic bacteria for pancreatic cancer chemo-immunotherapy

Immune evasion is a major obstacle for pancreatic ductal adenocarcinoma (PDAC) therapy. Inhibition of autophagy can improve antigen presentation and enlarge immunogenic cell death (ICD) effect to generate a strong anti-tumor immune response. However, abundant extracellular matrix dominated by hyaluronic acid (HA) hinders the deep penetration of autophagy inhibitors and ICD inducers. Herein, an intelligent autophagy inhibitor hydroxychloroquine (HCQ) and chemotherapeutic drug doxorubicin (DOX) co-loaded “bulldozer” (HD@HH/EcN) driven by anoxic bacteria was constructed for PDAC chemo-immunotherapy. Results demonstrated that probiotic Escherichia coli 1917 (EcN) could carry hyaluronidases (HAases)-hybrided albumin nanoparticles (HD@HH) to reach PDAC tumor tissue quickly and accurately. Thereafter, HAases can efficiently cleave the tumor matrix barrier and promote HD@HH/EcN to accumulate at tumor hypoxic core significantly. After that, high level of glutathione (GSH) in tumor microenvironment (TME) induces intermolecular disulfide bond in HD@HH nanoparticles breakage, to precisely release HCQ and DOX. DOX can induce ICD effect. Meanwhile, HCQ can amplify DOX induced ICD effect by inhibiting tumor autophagy, which further increase cell surface expression of major histocompatibility complex class I (MHC-I) and augment recruitment of CD8+ T cell to improve immunosuppressive TME. This study provides a new strategy for PDAC chemo-immunotherapy.

Autophagy Regulators in Cancer.

Autophagy plays a complex impact role in tumor initiation and development. It serves as a double-edged sword by supporting cell survival in certain situations while also triggering autophagic cell death in specific cellular contexts. Understanding the intricate functions and mechanisms of autophagy in tumors is crucial for guiding clinical approaches to cancer treatment. Recent studies highlight its significance in various aspects of cancer biology. Autophagy enables cancer cells to adapt to and survive unfavorable conditions by recycling cellular components. However, excessive or prolonged autophagy can lead to the self-destruction of cancer cells via a process known as autophagic cell death. Unraveling the molecular mechanisms underlying autophagy regulation in cancer is crucial for the development of targeted therapeutic interventions. In this review, we seek to present a comprehensive summary of current knowledge regarding autophagy, its impact on cancer cell survival and death, and the molecular mechanisms involved in the modulation of autophagy for cancer therapy.

ROS Responsive Nanoparticles Encapsulated with Natural Medicine Remodel Autophagy Homeostasis in Breast Cancer.

In photodynamic therapy (PDT), elevated reactive oxygen species (ROS) activate tumor cell protective autophagy, therefore attenuating the antitumor function of therapy. Hence, inhibition of protective autophagy in tumors can improve the antitumor effect of PDT. Herein, an innovative nanotraditional Chinese medicine system ((TP+A)@TkPEG NPs), which remodeled autophagy homeostasis, was fabricated. A photosensitizer aggregation inducing emission (AIE) and autophagy modulator triptolide (TP, an active ingredient of Tripterygium wilfordii Hook F) were encapsulated into ROS-responsive nanoparticles to improve antitumor effect of PDT in treatment of triple negative breast cancer. We proved that (TP+A)@TkPEG NPs effectively elevated intracellular ROS levels, activated ROS-responsive release of TP and inhibited the proliferation of 4T1 cells in vitro. More importantly, it sharply reduced autophagy related genes transcription and proteins expression in 4T1 cells, then promote cell apoptosis. In addition, this nanoherb therapeutic system effectively orientated to tumor sites, achieved efficient inhibition of tumor, and extended the survival time of 4T1-bearing mice in vivo. Further results confirmed that (TP+A)@TkPEG NPs remarkably inhibit the expression level of autophagy related initiation gene (becline-1) and elongation protein (light chain 3B) in tumor microenvironment and then block PDT induced protective autophagy. In brief, this system can remodel autophagy homeostasis and serve as an innovative approach for treatment of triple negative breast cancer.

Relationship Between Autophagy and Drug Resistance in Tumors.

Multidrug Resistance (MDR) in tumor cells, a phenomenon in which tumor cells become resistant to chemotherapeutic drugs with different chemical structures and mechanisms of action, is a major obstacle to tumor therapy and is an urgent problem to be addressed. Autophagy, widely found in eukaryotic cells, is a lysosome-dependent pathway of self-degradation. In different environments, autophagy can play different roles in the self-protection of cells. At different stages of tumorigenesis, autophagy can play two distinct roles: inhibition of cancer and promotion of cancer. The relationship between autophagy and drug resistance in tumor cells is complex. Moreover, autophagy can play a role in promoting drug resistance and drug sensitivity through different molecular pathways. This study aimed to investigate the relationship between autophagy and drug resistance in tumor cells from the perspective of molecular mechanisms.

Engineered bacterial outer membrane vesicles encapsulating oncolytic adenoviruses enhance the efficacy of cancer virotherapy by augmenting tumor cell autophagy

Oncolytic adenovirus (Ad) infection promotes intracellular autophagy in tumors. This could kill cancer cells and contribute to Ads-mediated anticancer immunity. However, the low intratumoral content of intravenously delivered Ads could be insufficient to efficiently activate tumor over-autophagy. Herein, we report bacterial outer membrane vesicles (OMVs)-encapsulating Ads as microbial nanocomposites that are engineered for autophagy-cascade-augmented immunotherapy. Biomineral shells cover the surface antigens of OMVs to slow their clearance during in vivo circulation, enhancing intratumoral accumulation. After entering tumor cells, there is excessive H2O2 accumulation through the catalytic effect of overexpressed pyranose oxidase (P2O) from microbial nanocomposite. This increases oxidative stress levels and triggers tumor autophagy. The autophagy-induced autophagosomes further promote Ads replication in infected tumor cells, leading to Ads-overactivated autophagy. Moreover, OMVs are powerful immunostimulants for remolding the immunosuppressive tumor microenvironment, facilitating antitumor immune response in preclinical cancer models in female mice. Therefore, the present autophagy-cascade-boosted immunotherapeutic method can expand OVs-based immunotherapy.

Polygalacin D inhibits the growth of hepatocellular carcinoma cells through BNIP3L-mediated mitophagy and endogenous apoptosis pathways.

Platycodon grandiflorum (Jacq.) A. DC. is a famous medicinal plant commonly used in East Asia. Triterpene saponins isolated from P. grandiflorum are the main biologically active compounds, among which polygalacin D (PGD) has been reported to be an anti-tumor agent. However, its anti-tumor mechanism against hepatocellular carcinoma is unknown. This study aimed to explore the inhibitory effect of PGD in hepatocellular carcinoma cells and related mechanisms of action. We found that PGD exerted significant inhibitory effect on hepatocellular carcinoma cells through apoptosis and autophagy. Analysis of the expression of apoptosis-related proteins and autophagy-related proteins revealed that this phenomenon was attributed to the mitochondrial apoptosis and mitophagy pathways. Subsequently, using specific inhibitors, we found that apoptosis and autophagy had mutually reinforcing effects. In addition, further analysis of autophagy showed that PGD induced mitophagy by increasing BCL2 interacting protein 3 like (BNIP3L) levels.In vivo experiments demonstrated that PGD significantly inhibited tumor growth and increased the levels of apoptosis and autophagy in tumors. Overall, our findings showed that PGD induced cell death of hepatocellular carcinoma cells primarily through mitochondrial apoptosis and mitophagy pathways. Therefore, PGD can be used as an apoptosis and autophagy agonist in the research and development of antitumor agents.

The relationship between autophagy and PD-L1 and their role in antitumor therapy.

Immune checkpoint blockade therapy is an important advance in cancer treatment, and the representative drugs (PD-1/PD-L1 antibodies) have greatly improved clinical outcomes in various human cancers. However, since many patients still experience primary resistance, they do not respond to anti-PD1/PD-L1 therapy, and some responders also develop acquired resistance after an initial response. Therefore, combined therapy with anti-PD-1/PD-L1 immunotherapy may result in better efficacy than monotherapy. In tumorigenesis and tumor development processes, the mutual regulation of autophagy and tumor immune escape is an intrinsic factor of malignant tumor progression. Understanding the correlation between the tumor autophagy pathway and tumor immune escape may help identify new clinical cancer treatment strategies. Since both autophagy and immune escape of tumor cells occur in a relatively complex microenvironmental network, autophagy affects the immune-mediated killing of tumor cells and immune escape. Therefore, comprehensive treatment targeting autophagy and immune escape to achieve "immune normalization" may be an important direction for future research and development. The PD-1/PD-L1 pathway is essential in tumor immunotherapy. High expression of PD-L1 in different tumors is closely related to poor survival rates, prognoses, and treatment effects. Therefore, exploring the mechanism of PD-L1 expression is crucial to improve the efficacy of tumor immunotherapy. Here, we summarize the mechanism and mutual relationship between autophagy and PD-L1 in antitumor therapy, which may help enhance current antitumor immunotherapy approaches.

Autophagy-related gene LAPTM4B promotes the progression of renal clear cell carcinoma and is associated with immunity.

Renal cell carcinoma (RCC) is a common urologic disease. Currently, surgery is the primary treatment for renal cancer; immunotherapy is not as effective a treatment strategy as expected. Hence, understanding the mechanism in the tumor immune microenvironment (TME) and exploring novel immunotherapeutic targets are considered important. Recent studies have demonstrated that autophagy could affect the immune environment of renal cell carcinoma and induce proliferation and apoptosis of cancer cells. By comparing lysosomal genes and regulating autophagy genes, we identified the LAPTM4B gene to be related to RCC autophagy. By analyzing the TCGA-KIRC cohort using bioinformatics, we found M2 macrophages associated with tumor metastasis to be significantly increased in the immune microenvironment of patients with high expression of LAPTM4B. GO/KEGG/GSEA/GSVA results showed significant differences in tumor autophagy- and metastasis-related pathways. Single-cell sequencing was used to compare the expression of LAPTM4B in different cell types and obtain the differences in lysosomal and autophagy pathway activities in different ccRCC cells. Subsequently, we confirmed the differential expression of LAPTM4B in renal cell carcinoma of different Fuhrman grades using western blotting. Downregulation of LAPTM4B expression significantly reduced the proliferation of renal cell carcinoma cells and promoted cell apoptosis through cell experiments. Overall, our study demonstrated that the autophagy-related gene LAPTM4B plays a critical role in the TME of RCC, and suggested that LAPTM4B is a potential therapeutic target for RCC immunotherapy.

The Role of ATG4A Clinical Implication and Potential Function in Breast Cancer

We studied the clinical implication and potential function of ATG4A in breast cancer by using publicly accessible patient data. The mRNA and protein levels of ATG4A were up-regulated in breast cancer tissues compared with normal breast tissues. ATG4A is a potential marker for prognosis, diagnosis and therapeutic target for breast cancer. Autophagy is a conservative catabolic process for cell homeostasis. The mechanism of autophagy in tumors is very complicated, since it can either promote or inhibit the occurrence and development of tumor according to different tumor stages and types. The purpose of this study was to investigate the clinical significance of an autophagy-related gene ATG4A in breast cancer. Transcriptional expression profiles of ATG4A between breast cancer tissues and normal tissues were retrieved from the Cancer Genome Atlas (TCGA). The ATG4A protein level was assessed by the Human Protein Atlas. The co-expression genes with ATG4A expression were analyzed using the LinkedOmics database. Protein–protein interaction (PPI) networks were constructed by the STRING. Paired t-test and Mann-Whitney U-test were used to determine the differences between breast cancer tissues and adjacent normal tissues. Kaplan–Meier curves and log rank tests were conducted for survival analysis. The expression of ATG4A in breast cancer tissues was significantly upregulated than those in adjacent normal tissues. Increased ATG4A mRNA expression was positively associated with lymph node metastases (P <0.05), ER positive (P <0.001), PR positive (P <0.001), HER-2 positive (P <0.05) and over 60 years of age (P <0.005). Compared with breast cancer patients with LumA, LumB and HER-2 positive subtypes, the expression of ATG4A mRNA in breast cancer patients with Basal was significantly lower (P <0.001). Kaplan–Meier survival analysis showed that the OS (P <0.001), DSS (P = 0.017) and PFI (P = 0.020) of breast cancer patients with high ATG4A mRNA expression were significantly shorter than those with low ATG4A mRNA expression. GO and KEGG analysis showed that Endocytosis might be a signal pathway involved in the occurrence and development of breast cancer by ATG4A. Furthermore, we found that RPL4, RPL11, RPL14, RPL29 and RPS9 may be the potential interacting genes of ATG4A in breast cancer by PPI analysis. ATG4A may be a potential diagnostic, prognostic biomarker and therapeutic target gene for breast cancer at the mRNA and protein levels.

Design and Screening of KLHL22 Inhibitors by Homology Modeling, Molecular Docking, and Molecular Dynamics Simulation

Background: Kelch-like protein 22 (KLHL22) was a newly discovered proto-oncogene and it is highly expressed in multiple breast cancer cell lines. Inhibition of KLHL22 can induce autophagy in tumor cells by regulating the mTORC1 pathway. Methods: In this study, the structure of the KLHL22 protein was predicted by homology modelling. The model was evaluated by Ramachandran Plot and Profile-3D. Virtual screening of a drug-like small molecule library of 400,000 compounds was performed, and six potentially active compounds were obtained. Results: Among them, compound 1 had the best docking posture with docking energy of -8.42 kcal/mol. Therefore, we further modified the structure of compound 1. 12 unreported compounds with lower docking energies were obtained. The results of ADMET prediction performed on them showed good druggability. The 60 ns molecular dynamics simulations were performed for compounds 1 and 10. MD studies showed that the complexes had stable RMSD, and the compounds formed good H-bonds interactions with essential amino acids (ASP64, TRP192). Conclusion: These results may provide new insights into the design and development of potent novel KLHL22 inhibitors.

Self-delivery biomedicine for enhanced photodynamic therapy by feedback promotion of tumor autophagy.

Reactive oxygen species (ROS) generated during photodynamic therapy (PDT) can induce autophagy to protect tumor cell from PDT-induced apoptosis. In this work, a self-delivery autophagy regulator (designated as CeCe) is developed for autophagy promotion sensitized PDT against tumor. Briefly, CeCe is prepared by the assembly of a photosensitizer of chlorin e6 (Ce6) and autophagy promoter of celastrol. By virtue of intermolecular interactions, Ce6 and celastrol are able to self-assemble into nanomedicine with great photodynamic performance and autophagy regulation capacity. Under light irradiation, CeCe would produce ROS in tumor cells to amplify the oxidative stress and promote cell autophagy. As a result, CeCe exhibits an enhanced photo toxicity by inducing autophagic cell death. In vivo experiments indicate that CeCe can predominantly accumulate in tumor tissue for a robust PDT. Moreover, CeCe has a superior therapeutic efficiency compared to monotherapy and combined treatment of Ce6 and celastrol, suggesting a synergistic antitumor effect of PDT and autophagy promotion. This self-delivery nanomedicine may advance the development of the co-delivery nanoplatform to improve the antitumor efficacy of PDT by promoting autophagy. STATEMENT OF SIGNIFICANCE: Autophagy is a "double-edged sword" in cellular homeostasis and metabolism, which can promote tumor progression but also induce an unknown impact on tumor inhibition. In this work, a self-delivery autophagy regulator (designated as CeCe) was developed for autophagy promotion sensitized photodynamic therapy (PDT). By virtue of intermolecular interactions, Ce6 and celastrol were found to self-assemble into stable CeCe without drug excipients, which exhibited great photodynamic performance and autophagy regulation capacity. In vitro and in vivo findings demonstrated a superior tumor suppression ability of CeCe over the monotherapy as well as the combined treatment of Ce6 and celastrol, suggesting a synergistic antitumor efficacy by PDT and autophagy promotion.

Autophagy: A challengeable paradox in cancer treatment.

Autophagy is an intracellular degradation pathway conserved in all eukaryotes from yeast to humans. This process plays a quality-control role by destroying harmful cellular components under normal conditions, maintaining cell survival, and establishing cellular adaptation under stressful conditions. Hence, there are various studies indicating dysfunctional autophagy as a factor involved in the development and progression of various human diseases, including cancer. In addition, the importance of autophagy in the development of cancer has been highlighted by paradoxical roles, as a cytoprotective and cytotoxic mechanism. Despite extensive research in the field of cancer, there are many questions and challenges about the roles and effects suggested for autophagy in cancer treatment. The aim of this study was to provide an overview of the paradoxical roles of autophagy in different tumors and related cancer treatment options. In this study, to find articles, a search was made in PubMed and Google scholar databases with the keywords Autophagy, Autophagy in Cancer Management, and Drug Design. According to the investigation, some studies suggest that several advanced cancers are dependent on autophagy for cell survival, so when cancer cells are exposed to therapy, autophagy is induced and suppresses the anti-cancer effects of therapeutic agents and also results in cell resistance. However, enhanced autophagy from using anti-cancer drugs causes autophagy-mediated cell death in several cancers. Because autophagy also plays roles in both tumor suppression and promotion further research is needed to determine the precise mechanism of this process in cancer treatment. We concluded in this article, autophagy manipulation may either promote or hinder the growth and development of cancer according to the origin of the cancer cells, the type of cancer, and the behavior of the cancer cells exposed to treatment. Thus, before starting treatment it is necessary to determine the basal levels of autophagy in various cancers.