Role of Autophagy in Renal Cancer

Targeting autophagy in urological system cancers: From underlying mechanisms to therapeutic implications

The urological system, including kidneys, ureters, bladder, urethra and prostate is known to be vital for blood filtration, waste elimination and electrolyte balance. Notably, urological system cancers represent a significant portion of global cancer diagnoses and mortalities. The current therapeutic strategies for early-stage cancer primarily involve resection surgery, which significantly affects the quality of life of patients, whereas advanced-stage cancer often relies on less effective chemo- or radiotherapy. Recently, accumulating evidence has revealed that autophagy, a crucial process in which excess organelles or inclusions within cells are removed to maintain cell homeostasis, has numerous links to urological system cancers. In this review, we focus on summarizing the underlying two-sided mechanisms of autophagy in urological system cancers. We also review the current clinical drugs targeting autophagy, which demonstrate significant potential in improving treatment outcomes for urological system cancers. In addition, we provide an overview of the research status of novel small molecule compounds targeting autophagy that are in the preclinical stages of investigation. Furthermore, drug combinations based on autophagy modulation strategies in urological system cancers are systematically summarized and discussed. These findings provide comprehensive new insight for the future discovery of more autophagy-related drug candidates.

LGALS3BP is a novel and potential biomarker in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is the most common solid renal tumor. Therefore, it is necessary to explore the related tumor markers. LGALS3BP (galectin 3 binding protein) is a multifunctional glycoprotein implicated in immunity and cancer. Some studies have shown that LGALS3BP promotes the occurrence and development of tumors. However, their exact role in renal tumorigenesis remains unclear. Our study used a webserver to explore the mRNA expression and clinical features of LGALS3BP in ccRCC. Survival analysis showed that patients with high LGALS3BP expression had significantly worse OS and DFS than those with low LGALS3BP expression. LGALS3BP expression is significantly related to B cells, CD4+ T cells, macrophages, neutrophils, and dendritic cells. Furthermore, we determined that LGALS3BP is significantly associated with angiogenesis, stemness and proliferation in renal cancer. Three phenotypes may be associated with a poor prognosis. Genes related to proliferation, angiogenesis and stemness were derived from a Venn diagram of FGF2. FGF2 is negatively correlated with proliferation and positively correlated with angiogenesis. Finally, we screened for drugs that may have potential therapeutic value for ccRCC. The PCR results showed that the expression of LGALS3BP in the normal cell line was lower than that in the tumor cell lines. After LGALS3BP knockdown, the proliferation of 769-P and 786-O cells decreased. The present findings show that LGALS3BP is critical for ccRCC cell proliferation and may be a potential target and biomarker for ccRCC.

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.

PLCL1 suppresses tumour progression by regulating AMPK/mTOR-mediated autophagy in renal cell carcinoma

Autophagy has been increasingly recognized as a critical regulatory mechanism in the maintenance of cellular homeostasis. A previous study showed that phospholipase C-like protein 1 (PLCL1) is associated with lipid metabolism in renal cell carcinoma (RCC). However, it is unclear whether PLCL1 regulates autophagy, thereby influencing the progression of RCC. Bioinformatics analysis of five microarray datasets revealed that expression of PLCL1 is decreased in tumours and is positively correlated with prognosis in RCC patients. Three independent public datasets, clinical RCC tissues and RCC cell lines, were validated using real-time qPCR, western blotting and immunohistochemistry. Using wound healing and transwell assays, we observed that elevated PLCL1 levels decreased the migratory distance and the invasive number of 786-O and ACHN cells, but PLCL1 knockdown reversed these changes in 769P cell lines compared to those in controls. The results of flow cytometry analysis indicated that PLCL1 promotes apoptosis. Moreover, transcriptional analysis based on stable overexpression of PLCL1 in 786-O cells revealed that PLCL1 is related to autophagy, and western blotting and autophagic experimental results further verified these findings. Mechanistic investigations confirmed that PLCL1 activates the AMPK/mTOR pathway and interacts with decidual protein induced by progesterone (DEPP). Collectively, our data suggest that PLCL1 functions as a suppressor of RCC progression by activating the AMPK/mTOR pathway, interacting with DEPP, initiating autophagy and inducing apoptosis. PLCL1 may be a promising therapeutic target for the diagnosis and treatment of ccRCC patients.

Research on the role of cellular autophagy in the sensitivity of human tongue cancer cells to radiotherapy and chemotherapy

OBJECTIVE

This paper aims to investigate the role of cisplatin-induced autophagy in human tongue squamous carcinoma Tca8113 cells.

METHODS

After inhibiting the expression of autophagic proteins with different autophagy inhibitors (3-methyladenine, chloroquine), the sensitivity of human tongue squamous cell carcinoma (Tca8113) cells to killing by gradient concentrations of cisplatin and gradient doses of radiation was detected using a colony formation assay. Further, the changes of autophagy expression in Tca8113 cells that had been treated with cisplatin and radiation were detected using western immunoblot, GFP-LC3 fluorescence and transmission electron microscopy.

RESULTS

The sensitivity of Tca8113 cells to cisplatin and radiation was significantly increased (P < 0.05) after reducing autophagy expression using different autophagy inhibitors. Meanwhile, the expression of autophagy in the cells was significantly increased by cisplatin and radiation treatment.

CONCLUSION

Tca8113 cells upregulated autophagy under the effect of either radiation or cisplatin, and the sensitivity of Tca8113 cells to cisplatin and radiation could be improved by inhibiting autophagy using multiple pathways.

Predicting response of immunotherapy and targeted therapy and prognosis characteristics for renal clear cell carcinoma based on m1A methylation regulators

In recent years, RNA methylation modification has been found to be related to a variety of tumor mechanisms, such as rectal cancer. Clear cell renal cell carcinoma (ccRCC) is most common in renal cell carcinoma. In this study, we get the RNA profiles of ccRCC patients from ArrayExpress and TCGA databases. The prognosis model of ccRCC was developed by the least absolute shrinkage and selection operator (LASSO) regression analysis, and the samples were stratified into low-high risk groups. In addition, our prognostic model was validated through the receiver operating characteristic curve (ROC). "pRRophetic" package screened five potential small molecule drugs. Protein interaction networks explore tumor driving factors and drug targeting factors. Finally, polymerase chain reaction (PCR) was used to verify the expression of the model in the ccRCC cell line. The mRNA matrix in ArrayExpress and TCGA databases was used to establish a prognostic model for ccRCC through LASSO regression analysis. Kaplan Meier analysis showed that the overall survival rate (OS) of the high-risk group was poor. ROC verifies the reliability of our model. Functional enrichment analysis showed that there was a obviously difference in immune status between the high-low risk groups. "pRRophetic" package screened five potential small molecule drugs (A.443654, A.770041, ABT.888, AG.014699, AMG.706). Protein interaction network shows that epidermal growth factor receptor [EGRF] and estrogen receptor 1 [ESR1] are tumor drivers and drug targeting factors. To further analyze the differential expression and pathway correlation of the prognosis risk model species. Finally, polymerase chain reaction (PCR) showed the expression of YTHN6-Methyladenosine RNA Binding Protein 1[YTHDF1], TRNA Methyltransferase 61B [TRMT61B], TRNA Methyltransferase 10C [TRMT10C] and AlkB Homolog 1[ALKBH1] in ccRCC cell lines. To sum up, the prognosis risk model we created not only has good predictive value, but also can provide guidance for accurately predicting the prognosis of ccRCC.

Clinical significance of SPOP and APC gene alterations in colorectal cancer in Indian population

Speckle-Type Poz Protein (SPOP) involved in the regulation of proteasome-mediated degradation of several oncoproteins, resulting in cancer initiation and progression. Mutations in Adenomatous Polyposis Coli (APC) gene is reported in most sporadic and hereditary colorectal cancer (CRC). Identifying the cellular changes involved in carcinogenesis when APC is mutated is an important issue that needs attention. The tumor suppressive function of SPOP and APC has long been a major focus in the research field of colorectal cancer. However, the clinical significance of SPOP and APC gene alteration in CRC has not been established to date. Mutational analysis was performed by single-strand conformational polymorphism followed by Sanger sequencing, methylation status by methylation-specific PCR, and protein expression by immunohistochemistry on 142 tumor tissues along with their adjacent non-cancerous specimens. The overall survival (OS) and recurrence free survival (RFS) were estimated by Kaplan-Meier Curve. Mutation rates of APC and SPOP gene were 2.8% and 11.9% while that of promoter hypermethylation were 37% and 47%, respectively. The grade of differentiation and Lymph node metastasis were significantly correlated with APC methylation pattern (p ≤ 0.05). The down regulation of APC was more often seen in colonic cancer compared to rectal cancer (p = 0.07) and more commonly in T3-4 depth of invasion (p = 0.07) and in patients without lymphovascular and perineural invasion (p = 0.007, p = 0.08 respectively). The median overall survival and recurrence free survival (RFS) was 67 & 36 months while 3-yr and 5-yr OS and RFS were 61.1% & 56.4% and 49.2% & 44.8%, respectively. APC promoter methylation had a better overall survival (p = 0.035) while loss of SPOP expression had a worse survival (p = 0.09). Our findings reveal high percentage of SPOP gene mutations in CRC. A significant link is found between promoter hyper methylation and protein expression in all mutant cases of APC and SPOP, suggesting that both genes may be associated in the development of colorectal cancer in people of Indian decent. Hypermethylation of APC gene and loss of SPOP expression have shown an association with disease prognosis and could be further studied looking at its potential role in planning adjuvant treatment in CRC patients.

Knocking down NSUN5 inhibits the development of clear cell renal cell carcinoma by inhibiting the p53 pathway

Clear cell renal cell carcinoma (ccRCC) is the most common solid renal tumor. NSUN5, a gene encoding cytosine-5 RNA methyltransferase, has rarely been reported associated with cancer. A bioinformatics analysis revealed that NSUN5 was overexpressed in ccRCC. Gene Ontology and gene set variation analyses showed that NSUN5 was associated with tumor immunity in ccRCC. The effect of immunosuppressive treatment was superior in the low-risk group compared to the high-risk group, and higher stromal score in the high-risk group relative to the low-risk group. A drug sensitivity analysis revealed that the high-risk group was more sensitive to 5-fluorouracil, mitomycin C, methotrexate, and 17-AAG, whereas the low-risk group was more sensitive to crizotinib, sorafenib, foretinib, and ivozanib. NSUN5 knockout decreased ccRCC cell proliferation. The migration speed and number of invasive cells further decreased. The percentage of apoptotic cells increased. In NSUN5-knockout cells, the levels of BAX, caspase-8, caspase-9, and p53 increased significantly, whereas those of Bcl2, CCND1, CCND3, and MMP9 decreased significantly. NSUN5 is highly expressed in ccRCC and inhibits cancer cell invasion, proliferation, and migration while promoting apoptosis by activating the p53 signaling pathway. This study provides insights into the mechanisms of action of NSUN5 in urological tumors and may contribute to improving ccRCC treatment options.

Interaction between STK33 and autophagy promoted renal cell carcinoma metastasis by regulating mTOR/ULK1 signaling pathway

BACKGROUND

The roles of STK33 in renal cell carcinoma (RCC) remain unclear. This study was designed to investigate the interaction between STK33 and the autophagy in the RCC.

METHODS AND RESULTS

STK33 was knocked down in 786-O and CAKI-1 cells. Then CCK8, clony formation assay, wound healing assay and Transwell assay were performed to analyze the proliferation, migration and invasion of the cancer cells. In addition, the activation of autophagy was determined using fluorescence, followed by investigating the potential signaling pathways in this process. After STK33 knockdown, the proliferation and migration of cell lines were inhibited, and the apoptosis of renal cancer cells was promoted. Autophagy fluorescence experiment showed that after STK33 knockdown, green LC3 protein fluorescence particles could be seen in the cells. Western blot analysis showed that after STK33 knockdown, there was significant down-regulation in P62 and p-mTOR, as well as significant up-regulation of Beclin1, LC3 and p-ULK1.

CONCLUSIONS

STK33 affected autophagy in RCC cells by activating mTOR/ ULK1pathway.

P53 and survivin expression in renal cell carcinoma

Objective

Mutation of p53 is detected in more than 50% of human cancers, expression of p53 has a potential prognostic value in patients with renal cell carcinoma (RCC). Survivin is a member of the inhibitor of apoptosis protein family, its overexpression is observed in many malignancies, including RCC. The aim of the study was to estimate a correlation between survivin and p53 expression in tumor samples and the histologic type of a tumor, tumor stage, tumor grade, and survival of patients.

Materials and Methods

Tumor samples were collected from surgical specimens of 90 patients who underwent radical or partial nephrectomy for RCC between November 2017 and July 2020. Tumors were staged according to the UICC (The Union for International Cancer Control) TNM classification system and histopathologically graded according to Fuhrman nuclear grade system. Histopathological diagnosis was confirmed with standard light microscopic evaluation, using hematoxylin and eosin staining and standard p53 and survivin antibodies.

Results

Positive p53 staining was observed in 36.7% of tumor specimens and 24.4% were survivin positive. There was a statistically significant correlation between p53 or survivin expression and histologic subtype of clear cell RCC as well as Type I and II of papillary RCC. There was a statistically significant correlation between p53 expression and tumor size, stage, and grade. The p53 or survivin expression was related to lower overall survival.

Conclusion

The results of this study suggest that p53 overexpression and survivin positivity in RCC patients could be associated with poor prognosis. Thus, these proteins could be used as prognostic markers in RCC.

FXR1 facilitates axitinib resistance in clear cell renal cell carcinoma via regulating KEAP1/Nrf2 signaling pathway

Axitinib is emerging as a first-line combination treatment drug for metastatic renal cell carcinoma, but the acquired resistance significantly bothers the treatment efficacy. This article is to investigate the impact of fragile X mental retardation autosomal homolog 1 (FXR1) and its mechanistic involvement with Kelch-like epoxy chloropropan-associated protein 1 (KEAP1)/NF-E2-related factor 2 (Nrf2) pathway on cell resistance to axitinib in clear cell renal cell carcinoma (ccRCC). Establishment of axitinib resistance cells (786-O, Caki-1, 786-O/axitinib, or Caki-1/axitinib) was made, and the cells were then transfected with sh-FXR1, or co-transfected with sh-FXR1 and sh-KEAP1. The quantitative real-time PCR (qRT-PCR) and western blotting assays were employed to measure the expression of FXR1, KEAP1, Nrf2, LC3 II/I, Beclin 1, p62, MDR-1, and MRP-1. In addition, the binding between FXR1 and KEAP1 was verified by RNA-immunoprecipitation and RNA pull-down assays, and FXR1-dependent KEAP1 mRNA degradation was determined. Herein, FXR1 was demonstrated to be overexpressed in ccRCC cells, and showed higher expression in 786-O/axitinib and Caki-1/axitinib cells. Mechanistically, FXR1 enriched KEAP1 mRNA, and pulled downed by biotinylated KEAP1 probes. Results of RNA stability assay reveled that KEAP mRNA stability was suppressed by FXR1. Furthermore, knockdown of FXR1 promoted cell apoptosis and showed a restrained feature on cell resistance to axitinib. Of note, KEAP1 knockdown suppressed cell autophagy, oxidative stress, resistance to axitinib, and promoted apoptosis, despite FXR1 was downregulated in ccRCC cells. In conclusion, FXR1 played an encouraging role in ccRCC cell resistance to axitinib by modulating KEAP/Nrf2 pathway.

Curcumin Inhibits Proliferation of Renal Cell Carcinoma in vitro and in vivo by Regulating miR-148/ADAMTS18 through Suppressing Autophagy

OBJECTIVE

To explore the effect of curcumin on the proliferation of renal cell carcinoma and analyze its regulation mechanism.

METHODS

In RCC cell lines of A498 and 786-O, the effects of curcumin (2.5, 5, 10 µ mo/L) on the proliferation were analyzed by Annexin V+PI staining. Besides, A498 was inoculated into nude mice to establish tumorigenic models, and the model mice were treated with different concentrations of curcumin (100, 200, and 400 mg/kg), once daily for 30 days. Then the tumor diameter was measured, the tumor cells were observed by hematoxylin-eosin staining, and the protein expressions of miR-148 and ADAMTS18 were detected by immunohistochemistry. In vitro, after transfection of miR-148 mimics, miR-148 inhibitor or si-ADAMTS18 in cell lines, the expression of ADAMTS18 was examined by Western blotting and the cell survival rate was analyzed using MTT. Subsequently, Western blot analysis was again used to examine the autophagy phenomenon by measuring the relative expression level of LC3-II/LC3-I; autophagy-associated genes, including those of Beclin-1 and ATG5, were also examined when miR-148 was silenced in both cell lines with curcumin treatment.

RESULTS

Curcumin could inhibit the proliferation of RCC in cell lines and nude mice. The expression of miR-148 and ADAMTS18 was upregulated after curcumin treatment both in vitro and in vivo (P<0.05). The cell survival rate was dramatically declined upon miR-148 or ADAMTS18 upregulated. However, si-ADAMTS18 treatment or miR-148 inhibitor reversed these results, that is, both of them promoted the cell survival rate.

CONCLUSION

Curcumin can inhibit the proliferation of renal cell carcinoma by regulating the miR-148/ ADAMTS18 axis through the suppression of autophagy in vitro and in vivo. There may exist a positive feedback loop between miR-148 and ADAMTS18 gene in RCC.

Curcumin in the treatment of urological cancers: Therapeutic targets, challenges and prospects

Urological cancers include bladder, prostate and renal cancers that can cause death in males and females. Patients with urological cancers are mainly diagnosed at an advanced disease stage when they also develop resistance to therapy or poor response. The use of natural products in the treatment of urological cancers has shown a significant increase. Curcumin has been widely used in cancer treatment due to its ability to trigger cell death and suppress metastasis. The beneficial effects of curcumin in the treatment of urological cancers is the focus of current review. Curcumin can induce apoptosis in the three types of urological cancers limiting their proliferative potential. Furthermore, curcumin can suppress invasion of urological cancers through EMT inhibition. Notably, curcumin decreases the expression of MMPs, therefore interfering with urological cancer metastasis. When used in combination with chemotherapy agents, curcumin displays synergistic effects in suppressing cancer progression. It can also be used as a chemosensitizer. Based on pre-clinical studies, curcumin administration is beneficial in the treatment of urological cancers and future clinical applications might be considered upon solving problems related to the poor bioavailability of the compound. To improve the bioavailability of curcumin and increase its therapeutic index in urological cancer suppression, nanostructures have been developed to favor targeted delivery.

Sunitinib versus Pazopanib Dilemma in Renal Cell Carcinoma: New Insights into the In Vitro Metabolic Impact, Efficacy, and Safety

Sunitinib and pazopanib are tyrosine kinase inhibitors (TKIs) used as first-line therapy for metastatic renal cell carcinoma (RCC). Although these TKIs are associated with similar survival outcomes, some differences have been reported in their safety profiles. In this work, traditional toxicological endpoints (cell viability and growth, oxidative stress, and nuclear morphology) and 1H NMR spectroscopy-based metabolomics analysis were used to provide new insights into the cytotoxicity and metabolic mechanisms underlying sunitinib and pazopanib treatments. Tumoral (Caki-1) and non-tumoral (HK-2) human renal cells were exposed to clinically relevant concentrations of sunitinib (2 µM) or pazopanib (50 µM). Sunitinib showed selectivity for cancer cells, inhibiting proliferation, and inducing apoptotic death of Caki-1 cells, whereas pazopanib had a similar cytotoxic effect in both tumoral and non-tumoral cells. 1H-NMR metabolomics unveiled a higher impact of sunitinib on the levels of intracellular metabolites of Caki-1 cells (seven dysregulated metabolites), suggesting dysregulations on amino acid, glutathione and glycerophospholipid metabolisms. In contrast, pazopanib had a higher impact on the levels of extracellular metabolites of Caki-1 cells (seven dysregulated metabolites in culture medium), unveiling alterations on amino acid and energetic metabolisms. In HK-2 cells, sunitinib caused only a minor increase in intracellular isoleucine levels, whereas pazopanib induced several alterations on the intracellular (three dysregulated metabolites) and extracellular (three dysregulated metabolites) compartments suggesting changes on amino acid, glycerophospholipid, and energy metabolisms. Our results demonstrate that these TKIs elicit distinct cellular and metabolic responses, with sunitinib showing better in vitro efficacy against target RCC cells and lesser nephrotoxic potential than pazopanib.

Construction and validation of an autophagy-related long non-coding RNA signature to predict the prognosis of kidney renal papillary cell carcinoma

To identify the autophagy-related long non-coding RNAs (ARlncRNAs) associated with the prognosis of kidney renal papillary cell carcinoma (KIRP), thereby establishing a clinical prognostic model. The gene expression matrix and clinical survival information of patients with KIRP were downloaded from The Cancer Genome Atlas database, and were divided into the training and testing groups. ARlncRNAs associated with the KIRP prognosis were analyzed by univariate, Least Absolute Shrinkage and Selection Operator (LASSO(, and multivariate Cox regression to construct a signature. We combined clinical factors associated with the prognosis with ARlncRNAs to establish a prognostic model of patients with KIRP. A nomogram was established to predict 1-year, 3-year, and 5-year survival of patients with KIRP. Besides, we built the lncRNA-messenger RNA co-expression network and used Kyoto Encyclopedia of Genes and Genomes and Gene Set Enrichment Analysis to detect the biological functions of ARlncRNAs. LEF1-AS1, CU634019.6, C2orf48, AC027228.2, and AC107464.3 were identified. A prognosis-related ARlncRNAs signature was constructed in the training group and validated in the testing group. Patients with KIRP with a low risk score had significantly longer survival time than those with a high risk score. The risk score significantly affected the prognosis of patients, thereby being used for modeling. The area under the receiver operating characteristic curve values of 1-year, 3-year, and 5-year overall survival were 0.80, 0.78, and 0.84 in the training group, respectively. The signature had high concordance index and good accuracy in predicting the prognosis, which were confirmed by the nomogram. The prognosis-related ARlncRNAs signature we identified had a more accurate prediction for the prognosis of patients with KIRP.

IFI35 Promotes Renal Cancer Progression by Inhibiting pSTAT1/pSTAT6-Dependent Autophagy

Interferon-induced protein 35 (IFI35), is currently acknowledged to govern the virus-related immune inflammatory responses. However, the biological significance and function of IFI35 in renal cell cancer (RCC) is still not well understood. Here, IFI35 expression and function were investigated in RCC tissues, renal cancer cells, and animal models. The results showed that IFI35 expression was significantly increased in 200 specimens of RCC patients. We found that higher IFI35 levels were significantly correlated with poor RCC prognosis. In human cell lines, the knockdown of IFI35 suppressed the malignant behavior of renal cancer cells. Similarly, the IFI35 knockdown resulted in significant inhibition of tumor progression in the subcutaneous or lung metastasis mouse model. Furthermore, the knockdown of IFI35 promoted the induction of autophagy by enhancing the autophagy-related gene expression (LC3-II, Beclin-1, and ATG-5). Additionally, blockade of STAT1/STAT6 phosphorylation (pSTAT1/pSTAT6) abrogated the induced autophagy by IFI35 knockdown in renal cancer cells. The autophagy inhibitor 3-MA also abolished the prevention of tumor growth by deleting IFI35 in renal cancer models. The above results suggest that the knockdown of IFI35 suppressed tumor progression of renal cancer by pSTAT1/pSTAT6-dependent autophagy. Our research revealed that IFI35 may serve as a potential diagnosis and therapeutic target for RCC.

Survival-related genes are diversified across cancers but generally enriched in cancer hallmark pathways

Background

Pan-cancer studies have disclosed many commonalities and differences in mutations, copy number variations, and gene expression alterations among cancers. Some of these features are significantly associated with clinical outcomes, and many prognosis-predictive biomarkers or biosignatures have been proposed for specific cancer types. Here, we systematically explored the biological functions and the distribution of survival-related genes (SRGs) across cancers.

Results

We carried out two different statistical survival models on the mRNA expression profiles in 33 cancer types from TCGA. We identified SRGs in each cancer type based on the Cox proportional hazards model and the log-rank test. We found a large difference in the number of SRGs among different cancer types, and most of the identified SRGs were specific to a particular cancer type. While these SRGs were unique to each cancer type, they were found mostly enriched in cancer hallmark pathways, e.g., cell proliferation, cell differentiation, DNA metabolism, and RNA metabolism. We also analyzed the association between cancer driver genes and SRGs and did not find significant over-representation amongst most cancers.

Conclusions

In summary, our work identified all the SRGs for 33 cancer types from TCGA. In addition, the pan-cancer analysis revealed the similarities and the differences in the biological functions of SRGs across cancers. Given the potential of SRGs in clinical utility, our results can serve as a resource for basic research and biotech applications.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08581-x.

A Combination therapy using an mTOR inhibitor and Honokiol effectively induces autophagy through the modulation of AXL and Rubicon in renal cancer cells and restricts renal tumor growth following organ transplantation

Development of cancer, including renal cancer, is a major problem in immunosuppressed patients. The mTOR inhibitor Rapamycin (RAPA) is used as an immunosuppressive agent in patients with organ transplants and other immunological disorders; and it also has antitumorigenic potential. However, long-term use of RAPA causes reactivation of Akt, and ultimately leads to enhanced tumor growth. Honokiol (HNK) is a natural compound, which possesses both anti-inflammatory and antitumorigenic properties. In this study, we investigated the effect of a novel combination therapy using RAPA + HNK on allograft survival and post-transplantation renal tumor growth. We observed that it effectively modulated the expression of some key regulatory molecules (like Carabin, an endogenous Ras inhibitor; and Rubicon, a negative regulator of autophagy) that play important roles in tumor cell growth and survival. This combination induced toxic autophagy and apoptosis to promote cancer cell death; and was associated with a reduced expression of the tumor-promoting receptor tyrosine kinase AXL. Finally, we utilized a novel murine model to examine the effect of RAPA + HNK on post-transplantation renal tumor growth. The combination treatment prolonged the allograft survival and significantly inhibited post-transplantation tumor growth. It was associated with reduced tumor expression of Rubicon and the cytoprotective/antioxidant heme oxygenase-1 to overcome therapeutic resistance. It also downregulated the coinhibitory programmed death-1 ligand, which plays major role(s) in the immune escape of tumor cells. Together, this combination treatment has a great potential to restrict renal tumor growth in transplant recipients as well as other immunosuppressed patients.

Esterase D stabilizes FKBP25 to suppress mTORC1

Background

Esterase D (ESD) is a nonspecific esterase that detoxifies formaldehyde. Many reports have stated that ESD activity is associated with a variety of physiological and pathological processes. However, the detailed signaling pathway of ESD remains poorly understood.

Methods

Considering the advantages of the small chemical molecule, our recent work demonstrated that 4-chloro-2-(5-phenyl-1-(pyridin-2-yl)-4,5-dihydro-1H-pyrazol-3-yl) phenol (FPD5) activates ESD, and will be a good tool for studying ESD further. Firstly, we determined the interaction between ESD and FK506 binding protein 25 (FKBP25) by yeast two-hybrid assay and co-immunoprecipitation (CO-IP) and analyzed the phosphorylation levels of mTORC1, P70S6K and 4EBP1 by western blot. Furthermore, we used the sulforhodamine B (SRB) and chick chorioallantoic membrane (CAM) assay to analyze cell viability in vitro and in vivo after treatment with ESD activator FPD5.

Results

We screened FKBP25 as a candidate protein to interact with ESD by yeast two-hybrid assay. Then we verified the interaction between ESD and endogenous FKBP25 or ectopically expressed GFP-FKBP25 by CO-IP. Moreover, the N-terminus (1–90 aa) domain of FKBP25 served as the crucial element for their interaction. More importantly, ESD reduced the K48-linked poly-ubiquitin chains of FKBP25 and thus stabilized cytoplasmic FKBP25. ESD also promoted FKBP25 to bind more mTORC1, suppressing the activity of mTORC1. In addition, ESD suppressed tumor cell growth in vitro and in vivo through autophagy.

Conclusions

These findings provide novel evidence for elucidating the molecular mechanism of ESD and ubiquitination of FKBP25 to regulate autophagy and cancer cell growth. The ESD/FKBP25/mTORC1 signaling pathway is involved in inhibiting tumor cell growth via regulating autophagy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11658-021-00297-2.

Fumarate hydratase-deficient renal cell carcinoma: A tumor with diverse morphology including cannibalism, lymphocytic emperipolesis, and defective autophagy

We report the clinicopathological findings of the first series of 3 patients from Brazil with fumarate hydratase-deficient renal cell carcinoma. The clinicopathological findings disclosed a very aggressive tumor. All 3 patients had solitary tumor at the left side, metastasis and advanced stage at the time of diagnosis; were females with a median age of 40 years; had a history of uterine leiomyomas; and, at follow-up two patients are deceased and one patient alive. The microscopic findings of these 3 patients are in accordance with the literature disclosing a variety of morphologic features being papillary arrangement, eosinophilic cytoplasm, and prominent nucleoli surrounded by clear halo the constant and most frequent findings. Previously not reported in this tumor, we describe presence of cannibalism, lymphocytic emperipolesis, and cytoplasmic vacuoles with eosinophilic inclusions associated with overexpression of p62 in immunohistochemistry which is considered to be evidence of defective autophagy. Lymphocytic emperipolesis was a more frequent finding than cannibalism and immunohistochemistry for p62 was overexpressed only in the 2 patients disclosing cytoplasmic vacuoles with eosinophilic inclusions. The presence, frequency and significance of these novel findings should be checked in large series of this rare and aggressive tumor aiming to associate with clinical behavior and eventually influence the strategy of treatment.

PRR11 promotes ccRCC tumorigenesis by regulating E2F1 stability

Proline rich 11 (PRR11), a novel tumor-related gene, has been identified in different tumors. However, the relevant biological functions of PRR11 in human clear cell renal cell carcinoma (ccRCC) have not been studied. In this study, we first identified PRR11 as a biomarker of ccRCC and predictor of poor prognosis by bioinformatics. Then, we showed that PRR11 silencing substantially reduced ccRCC cell proliferation and migration in vitro and in vivo. Importantly, we found that PRR11 induced the degradation of the E2F1 protein through its interaction with E2F1, and PRR11 reduced the stability of the E2F1 protein in ccRCC cells, thereby affecting cell cycle progression. Further results indicated that the downregulation of E2F1 expression partially reversed the changes in ccRCC cell biology caused by PRR11 deletion. In addition, we showed that PRR11 was a target gene of c-Myc. The transcription factor c-Myc may have promoted the expression of PRR11 in ccRCC cells by binding to the PRR11 promoter region, thereby accelerating the progression of ccRCC. In summary, we found that PRR11 served as an oncogene in ccRCC, and PRR11 reduced the protein stability of E2F1 and could be activated by c-Myc.

Celastrol induces lipophagy via the LXRα/ABCA1 pathway in clear cell renal cell carcinoma

Celastrol is a triterpene derived from the traditional Chinese medicine Tripterygium wilfordii Hook f, which displays potential anticancer activity. In the present study, we investigated the anticancer effects of celastrol against clear cell renal cell carcinoma (ccRCC) and the underlying mechanisms. Using Cancer Genome Atlas (TCGA) database and genotype-tissue expression (GTEx) database we conducted a bioinformatics analysis, which showed that the mRNA levels of liver-X receptors α (LXRα) and ATP-binding cassette transporter A1 (ABCA1) in ccRCC tissues were significantly lower than those in adjacent normal tissues. This result was confirmed by immunoblotting analysis of 4 ccRCC clinical specimens, which showed that the protein expression of LXRα and ABCA1 was downregulated. Similar results were obtained in a panel of ccRCC cell lines (786-O, A498, SN12C, and OS-RC-2). In 786-O and SN12C cells, treatment with celastrol (0.25-2.0 μM) concentration-dependently inhibited the cell proliferation, migration, and invasion as well as the epithelial-mesenchymal transition (EMT) process. Furthermore, we demonstrated that celastrol inhibited the invasion of 786-O cells through reducing lipid accumulation; celastrol concentration-dependently promoted autophagy to reduce lipid storage. Moreover, we revealed that celastrol dramatically activated LXRα signaling, and degraded lipid droplets by inducing lipophagy in 786-O cells. Finally, celastrol promoted cholesterol efflux from 786-O cells via ABCA1. In high-fat diet-promoted ccRCC cell line 786-O xenograft model, administration of celastrol (0.25, 0.5, 1.0 mg·kg-1·d-1, for 4 weeks, i.p.) dose-dependently inhibited the tumor growth with upregulated LXRα and ABCA1 protein in tumor tissue. In conclusion, this study reveals that celastrol triggers lipophagy in ccRCC by activating LXRα, promotes ABCA1-mediated cholesterol efflux, suppresses EMT progress, and ultimately inhibits cell proliferation, migration, and invasion as well as tumor growth. Thus, our study provides evidence that celastrol can be used as a lipid metabolism-based anticancer therapeutic approach.

LINC00671 inhibits renal cell cancer progression via regulating miR-221-5p/SOCS1 axis

BACKGROUND

Long non-coding RNA (lncRNA) has gradually received widespread attention due to its role in regulating tumor progression. However, in renal cell cancer (RCC), the exact function of lncRNA LINC00671 remains uncertain.

METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR) was utilized for detecting LINC00671 and miR-221-5p expressions in RCC tissues and cell lines. Western blotting technique was utilized for detecting the expressions of epithelial-mesenchymal transition (EMT)-associated proteins (E-cadherin and N-cadherin) and suppressor of cytokine signaling 1 (SOCS1). The correlation between clinicopathological features and LINC00671 expression was also evaluated. RCC cell multiplication, migration and invasion were measured by CCK-8, EdU and Transwell assays, respectively. The targeted relationships between LINC00671 as well as the SOCS1 3'UTR and miR-221-5p were verified by RNA immunoprecipitation (RIP) and luciferase reporter gene assay.

RESULTS

LINC00671 expression in RCC tissues and cells was significantly reduced. Patients with low LINC00671 expression had relatively shorter disease-free survival and overall survival. Moreover, LINC00671 expression was linked to lymph node metastasis, tumor stage, and tumor size. In Caki-1 and 769-P cell lines, LINC00671 overexpression restrained the multiplication, migration, invasion, as well as the EMT process of RCC cells in vitro. In terms of mechanism, miR-221-5p was identified as a target of LINC00671, and LINC00671 could up-regulate SOCS1 by repressing miR-221-5p.

CONCLUSION

LINC00671 regulates the miR-221-5p/SOCS1 axis as a tumor suppressor in RCC.

Clear Cell Renal Carcinoma: MicroRNAs With Efficacy in Preclinical In Vivo Models

In order to identify new targets and treatment modalities for clear cell renal carcinoma, we surveyed the literature with respect to microRNAs involved in this disease. In this review, we have focused on up- and down-regulated miRs which mediate efficacy in preclinical clear-cell renal carcinoma-related in vivo models. We have identified 10 up-regulated and 33 down-regulated micro-RNAs according to this criterion. As proof-of-concept, micro-RNAs interfering with VEGF (miR-205p) and mTOR (mir-99a) pathways, which are modulated by approved drugs for this disease, have been identified. miRs targeting hypoxia induced factor-2α (HIF-2α) (miR-145), E3 ubiquitinylases speckle-type POZ protein (SPOP) (miR 520/372/373) and casitas B-lineage lymphoma (CBL) (miR-200a-3p), interfere with druggable targets. Further identified miRs interfere with cell-cycle dependent kinases, such as CDK2 (miR-200c), CDK4, 6 (miR-1) and CDK4, 9 (206c). Transmembrane receptor Ral interacting protein of 76 kD (RLIP76), targeted by mir-137, has emerged as another important target for ccRCC. Additional miRs and their targets merrying further preclinical validation are discussed.

Construction and validation of an autophagy-related long noncoding RNA signature for prognosis prediction in kidney renal clear cell carcinoma patients

Purpose

The purpose of this study was to identify autophagy‐associated long noncoding RNAs (ARlncRNAs) using the kidney renal clear cell carcinoma (KIRC) patient data from The Cancer Genome Atlas (TCGA) database and to construct a prognostic risk‐related ARlncRNAs signature to accurately predict the prognosis of KIRC patients.

Methods

The KIRC patient data were originated from TCGA database and were classified into a training set and testing set. Seven prognostic risk‐related ARlncRNAs, identified using univariate, lasso, and multivariate Cox regression analysis, were used to construct prognostic risk‐related signatures. Kaplan–Meier curves and receiver operating characteristic (ROC) curves as well as independent prognostic factor analysis and correlation analysis with clinical characteristics were utilized to evaluate and verify the specificity and sensitivity of the signature in training set and testing set, respectively. Two nomograms were established to predict the probable 1‐, 3‐, and 5‐year survival of the KIRC patients. In addition, the lncRNA‐mRNA co‐expression network was constructed and Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to identify biological functions of ARlncRNAs.

Results

We constructed and verified a prognostic risk‐related ARlncRNAs signature in training set and testing set, respectively. We found the survival time of KIRC patients with low‐risk scores was significantly better than those with high‐risk scores in training set and testing set. ROC curves suggested that the area under the ROC (AUC) value for prognostic risk score signature was 0.81 in training set and 0.705 in testing set. And AUC values corresponding to 1‐, 3‐, and 5 years of OS were 0.809, 0.753, and 0.794 in training set and 0.698, 0.682, and 0.754 in testing set, respectively. We established the two nomograms that confirmed high C‐index and accomplished good prediction accuracy.

Conclusions

We constructed a prognostic risk‐related ARlncRNAs signature that could accurately predict the prognosis of KIRC patients.

Autophagy as a Vital Therapy Target for Renal Cell Carcinoma

Autophagy is a process that degrades and recycles superfluous organelles or damaged cellular contents. It has been found to have dual functions in renal cell carcinoma (RCC). Many autophagy-related proteins are regarded as prognostic markers of RCC. Researchers have attempted to explore synthetic and phytochemical drugs for RCC therapy that target autophagy. In this review, we highlight the importance of autophagy in RCC and potential treatments related to autophagy.

Autophagy and renal cell carcinoma: What do we know so far?

Renal cell carcinoma (RCC) is the most common type of kidney tumor in adults, accounting for approximately 90% of kidney malignances, occurring usually between the ages of 60 and 70. The 5-year overall survival rate for all RCC types is 49%. Since RCCs are resistant to numeorus different radio and chemotherapeutics that act via apoptosis induction, the development of new approaches to RCC treatment is still in the focus of modern urology. In particular, in recent years, autophagy in RCC has been widely studied as a mechanism of cell extinction through which tumor cells can overcome resistance to apoptosis activation therapy. Autophagy is often referred to as a double-edged sword because it can be a process that allows cells of cancer to survive and, on the other hand and under other conditions, it can be a cell dying mechanism, independent or closely related to other cell death modalities, like apoptosis and necrosis. The central role in the tempering of the process of autophagy, in general, belongs to the mTOR complex (mammalian target of rapamycin), which integrates numerous signals that affect autophagy, such as growth factors, nutrients, various stressors and the energy status of the cell. In RCC, the most important is PI3K/AKT/mTOR signaling pathway, since activation of this signaling leads to survival of tumor cells through mTOR activation and thus, autophagy inhibition. Up to now, it was found that autophagy markers such as Beclin-1 and LC3-II can be considered as prognostic markers for RCC since the high level of Beclin-1 was detected in tissues and cells of RCC (A498 and ACHN cell lines) and that tumor cell mobility is promoted by the up-regulated expression of LC3. Therefore, a progress in RCC therapy can be expected from the development and synthesis of specific compounds targeting autophagy, as well as the therapy based on their combination.

TRPM Channels in Human Diseases

The transient receptor potential melastatin (TRPM) subfamily belongs to the TRP cation channels family. Since the first cloning of TRPM1 in 1989, tremendous progress has been made in identifying novel members of the TRPM subfamily and their functions. The TRPM subfamily is composed of eight members consisting of four six-transmembrane domain subunits, resulting in homomeric or heteromeric channels. From a structural point of view, based on the homology sequence of the coiled-coil in the C-terminus, the eight TRPM members are clustered into four groups: TRPM1/M3, M2/M8, M4/M5 and M6/M7. TRPM subfamily members have been involved in several physiological functions. However, they are also linked to diverse pathophysiological human processes. Alterations in the expression and function of TRPM subfamily ion channels might generate several human diseases including cardiovascular and neurodegenerative alterations, organ dysfunction, cancer and many other channelopathies. These effects position them as remarkable putative targets for novel diagnostic strategies, drug design and therapeutic approaches. Here, we review the current knowledge about the main characteristics of all members of the TRPM family, focusing on their actions in human diseases.

Role of AMPK/mTOR-independent autophagy in clear cell renal cell carcinoma

We examined the status and role of autophagy, a process of lysosomal recycling of cellular material, in clear cell renal cell carcinoma (ccRCC). Paired samples of tumor and adjacent non-malignant tissue were collected from 20 patients with ccRCC after radical nephrectomy. The mRNA levels of apoptosis (BAD, BAX, BCL2, BCLXL, BIM) and autophagy (ATG4, BECN1, GABARAP, p62, UVRAG) regulators were measured by RT-qPCR. The protein levels of autophagosome-associated LC3-II, autophagy receptor p62, apoptotic marker PARP, as well as phosphorylation of autophagy initiator Unc 51-like kinase 1 (ULK1), its activator AMP-activated protein kinase (AMPK) and 4EBP1, the substrate of ULK1 inhibitor mechanistic target of rapamycin (mTOR), were analyzed by immunoblotting. The mRNA levels of pro-apoptotic BAX, anti-apoptotic BCLXL and pro-autophagic ATG4, p62 and UVRAG were higher in ccRCC tumors. Autophagy induction was confirmed by an increase in phospho-ULK1 and degradation of the autophagic target p62, while apoptotic PARP cleavage was unaltered. AMPK phosphorylation was reduced and 4EBP1 phosphorylation was increased in ccRCC tissue. The expression of apoptosis regulators did not correlate with clinicopathological features of ccRCC. Conversely, high mRNA levels of ATG4, GABARAP and p62 were associated with lower tumor stage, as well as with smaller tumor size and better disease-specific 5-year survival (ATG4 and p62). Accordingly, low p62 protein levels, corresponding to increased autophagic flux, were associated with lower tumor stage, reduced metastasis and improved 5-year survival. These data demonstrate that transcriptional induction of autophagy in ccRCC is accompanied by AMPK/mTOR-independent increase in ULK1 activation and autophagic flux, which might slow tumor progression and metastasis independently of apoptosis.

An actin-WHAMM interaction linking SETD2 and autophagy

The process of autophagy is dysregulated in many cancers including clear cell renal cell carcinoma (ccRCC). Autophagy involves the coordination of numerous autophagy-related (ATG) genes, as well as processes involving the actin cytoskeleton. The histone methyltransferase SETD2, frequently inactivated in ccRCC, has recently been shown to also methylate cytoskeletal proteins, which in the case of actin lysine 68 trimethylation (ActK68me3) regulates actin polymerization dynamics. Here we show that cells lacking SETD2 exhibit autophagy defects, as well as decreased interaction of the actin nucleation promoting factor WHAMM with its target actin, which is required for initiation of autophagy. Interestingly, the WHAMM actin binding deficit could be rescued with pharmacologic induction of actin polymerization in SETD2-null cells using Jasplakinolide. These data indicate that the decreased interaction between WHAMM and its target actin in SETD2-null cells was secondary to altered actin dynamics rather than loss of the SETD2 ActK68me3 mark itself, and underscores the importance of the functional defect in actin polymerization in SETD2-null cells exhibiting autophagy defects.

Identification of an independent autophagy-gene prognostic index for papillary renal cell carcinoma

Background

Autophagy was a significant catabolic process which played a critical role in the maintenance of cellular homeostasis and viability in a stressed state. The dysregulation of autophagy was correlated with various diseases. The aim of our study was to develop a prognostic signature for papillary renal cell carcinoma (RCC).

Methods

First, 40 differently expressed genes related with autophagy (ARGs) were examined via high-throughput sequencing and large-scale databases. Then, functional enrichment analysis was performed to explore the biological attributes of these ARGs. The Cox proportional hazard regression hinted that four ARGs (P4HB, BIRC5, NGR1 and PRKN) were significantly correlated with overall survival (OS). Thus, we got genes with prognostic value. Finally, a prognostic index (PI) was constructed.

Results

After identifying the 4 ARGs, we profiled our risk signature. Based on the PI we developed, papillary RCC patients were stratified into high-risk and low-risk groups. High-risk patients had significant shorter OS than low-risk patients (P<0.001) and the mortality of high scoring patients was higher than low scoring patients. Additionally, we explored the relationship between the 4 ARGs and clinical parameters and found that the expression of P4HB, BIRC5 and NGR1 was correlated with clinicopathological features.

Conclusions

Our study suggested that the four-gene signature was an independent prognostic factor which could act as a novel indicator for the prognosis of papillary RCC.

Autophagy and its role in regeneration and remodeling within invertebrate

Background

Acting as a cellular cleaner by packaging and transporting defective proteins and organelles to lysosomes for breakdown, autophagic process is involved in the regulation of cell remodeling after cell damage or cell death in both vertebrate and invertebrate. In human, limitations on the regenerative capacity of specific tissues and organs make it difficult to recover from diseases. Comprehensive understanding on its mechanism within invertebrate have strong potential provide helpful information for challenging these diseases.

Method

In this study, recent findings on the autophagy function in three invertebrates including planarian, hydra and leech with remarkable regenerative ability were summarized. Furthermore, molecular phylogenetic analyses of DjATGs and HvATGs were performed on these three invertebrates compared to that of Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, Mus musculus and Homo sapiens.

Results

In comparison with Scerevisiae, C elegans, D melanogaster, M musculus and human, our analysis exhibits the following characteristics of autophagy and its function in regeneration within invertebrate. Phylogenetical analysis of ATGs revealed that most autophagy-related genes (ATGs) were highly similar to their homologs in other species, which indicates that autophagy is a highly conservative biological function in both vertebrate and invertebrate. Structurally, almost all the core amino acids necessary for the function of ATG8 in mammal were observed in invertebrate HvATG8s and DjATG8s. For instance, ubiquitin-like domain as a signature structure in each ATG8, was observed in all ATG8s in three invertebrates. Basically, autophagy plays a key role in the regulation of regeneration in planarian. DjATG8-2 and DjATG8-3 associated with mTOR signaling pathway are sophisticated in the invertebrate tissue/organ regeneration. Furthermore, autophagy is involved in the pathway of neutralization of toxic molecules input from blood digestion in the leech.

Conclusions

The recent investigations on autophagy in invertebrate including planarian, hydra and leech suggest that autophagy is evolutionally conserved from yeast to mammals. The fundamental role of its biological function in the invertebrate contributing to the regeneration and maintenance of cellular homeostasis in these three organisms could make tremendous information to confront life threatening diseases in human including cancers and cardiac disorders.

LncRNA HOTAIR induces sunitinib resistance in renal cancer by acting as a competing endogenous RNA to regulate autophagy of renal cells

Background

Cell autophagy has been proposed to be involved in drug resistance therapy. However, how the long non-coding RNA (lncRNA) reduces risks of drug resistance in renal cancer (RC) cells needs a thorough inquiry. This study was assigned to probe the effect and mechanism of HOTAIR on sunitinib resistance of RC.

Methods

Clinical RC tissues and para-carcinoma tissues were obtained to detect the expressions of miR-17-5p, HOTAIR and Beclin1. Sunitinib-resistant cells (786-O-R and ACHN-R) were constructed using parental RC cells (786-O and ACHN). The resistance of 786-O-R and ACHN-R cells to sunitinib was examined. Western blot and qRT-PCR were assayed to obtain the expressions of miR-17-5p, HOTAIR and Beclin1. The effects of HOTAIR knockdown or miR-17-5p overexpression/knockdown on cell autophagy and sunitinib resistance were measured by MDC staining, immunofluorescence and Western blot. The sensitivity of RC cells to sunitinib and change in cell clone formation after sunitinib treatment were assessed by CCK-8 assay and colony formation assay, respectively. The relationships among HOTAIR, miR-17-5p and Beclin1 were verified by dual-luciferase reporter gene and RIP assay. The role of HOTAIR knockdown in sunitinib resistance was verified in nude mice.

Results

HOTAIR expression in sunitinib-resistant cells is higher than that in parental cells. Knockdown of HOTAIR in sunitinib-resistant cells lead to refrained sunitinib resistance and cell autophagy both in vivo and in vitro. Activation of autophagy could raise resistance to sunitinib in RC cells, while inhibition of autophagy could improve the sensitivity of sunitinib-resistant cells to sunitinib. HOTAIR could compete with miR-17-5p to regulate Beclin1 expression. Knockdown of miR-17-5p in parental cells increases cell resistant to sunitinib, and overexpression of miR-17-5p in sunitinib-resistant cells increases cell sensitive to sunitinib.

Conclusion

HOTAIR negatively targets miR-17-5p to activate Beclin1-mediated cell autophagy, thereby enhancing sunitinib resistance in RC cells.

Inhibition of Transglutaminase 2 but Not of MDM2 Has a Significant Therapeutic Effect on Renal Cell Carcinoma

More than 50% of human cancers harbor TP53 mutations and increased expression of Mouse double minute 2 homolog(MDM2), which contribute to cancer progression and drug resistance. Renal cell carcinoma (RCC) has an unusually high incidence of wild-type p53, with a mutation rate of less than 4%. MDM2 is master regulator of apoptosis in cancer cells, which is triggered through proteasomal degradation of wild-type p53. Recently, we found that p53 protein levels in RCC are regulated by autophagic degradation. Transglutaminase 2 (TGase 2) was responsible for p53 degradation through this pathway. Knocking down TGase 2 increased p53-mediated apoptosis in RCC. Therefore, we asked whether depleting p53 from RCC cells occurs via MDM2-mediated proteasomal degradation or via TGase 2-mediated autophagic degradation. In vitro gene knockdown experiments revealed that stability of p53 in RCC was inversely related to levels of both MDM2 and TGase 2 protein. Therefore, we examined the therapeutic efficacy of inhibitors of TGase 2 and MDM2 in an in vivo model of RCC. The results showed that inhibiting TGase 2 but not MDM2 had efficient anticancer effects.

Identification of an Autophagy-Related Prognostic Signature for Clear Cell Renal Cell Carcinoma

Abnormal autophagy is closely related to the development of cancer. Many studies have demonstrated that autophagy plays an important role in biological function in clear cell renal cell carcinoma (ccRCC). This study aimed to construct a prognostic signature for ccRCC based on autophagy-related genes (ARGs) to predict the prognosis of ccRCC. Differentially expressed ARGs were obtained from ccRCC RNA-seq data in The Cancer Genome Atlas (TCGA) database. ARGs were enriched by gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). The prognostic ARGs used to construct the risk score models for overall survival (OS) and disease-free survival (DFS) were identified by Cox regression analyses. According to the median value of the risk score, patients were divided into a high-risk group and a low-risk group. The OS and DFS were analyzed by the Kaplan-Meier method. The predictive accuracy was determined by a receiver operating characteristic (ROC) curve analysis. Additionally, we performed stratification analyses based on different clinical variables and evaluated the correlation between the risk score and the clinical variables. The differentially expressed ARGs were mainly enriched in the platinum drug resistance pathway. The prognostic signatures based on 11 ARGs for OS and 5 ARGs for DFS were constructed and showed that the survive time was significantly shorter in the high-risk group than in the low-risk group (P < 0.001). The ROC curve for OS exhibited good predictive accuracy, with an area under the curve value of 0.738. In the stratification analyses, the OS time of the high-risk group was shorter than that of the low-risk group stratified by different clinical variables. In conclusion, an autophagy-related signature for OS we constructed can independently predict the prognosis of ccRCC patient, and provide a deep understanding of the potential biological mechanisms of autophagy in ccRCC.

Effects of autophagy-associated genes on the prognosis for lung adenocarcinoma

Background

Several studies show that autophagy plays an important part in the biological processes of lung adenocarcinoma. Therefore, this work aimed to establish one scoring system on the basis of the expression profiles of differentially expressed autophagy-related genes (DEARGs) in patients with lung adenocarcinoma.

Methods

The Cancer Genome Atlas (TCGA) was applied to retrieve lung adenocarcinoma data. The overall survival (OS)-associated DEARGs were selected for the DEARG scoring scale. Moreover, the online database Kaplan-Meier Plotter (www.Kmplot.com) was employed to verify the accuracy of our results.

Results

The expression patterns of DEARG were detected in lung adenocarcinoma as well as normal lung tissues. A gene set related to autophagy was identified, along with 9 genes that showed marked significance in predicting the lung adenocarcinoma prognosis. According to the cox regression results, DEARGs (including ITGB4, BIRC5, ERO1A, and NLRC4) were applied to calculate the DEARGs risk score. Patients with lower DEARGs risk scores were associated with better OS. Moreover, based on analysis with the receiver operating characteristic (ROC) curve, DEARGs accurately distinguished the healthy tissues from lung adenocarcinoma tissues [area under the curve (AUC) value of >0.6].

Conclusions

A scoring system is constructed based on the primary DEARGs, which accurately predicts the outcomes of lung adenocarcinoma.

SETD2 mutation in renal clear cell carcinoma suppress autophagy via regulation of ATG12

Inactivating mutations in the SETD2 gene, encoding for a nonredundant histone H3 methyltransferase and regulator of transcription, is a frequent molecular feature in clear cell renal cell carcinomas (ccRCC). SETD2 deficiency is associated with recurrence of ccRCC and bears low prognostic values. Targeting autophagy, a conserved catabolic process with critical functions in maintenance of cellular homeostasis and cell conservation under stress condition, is emerging as a potential therapeutic strategy to combat ccRCC. Epigenetics-based pathways are now appreciated as key components in the regulation of autophagy. However, whether loss of function in the SETD2 histone modifying enzyme occurring in ccRCC cells may impact on their ability to undergo autophagy remained to be explored. Here, we report that SETD2 deficiency in RCC cells is associated with the aberrant accumulation of both free ATG12 and of an additional ATG12-containing complex, distinct from the ATG5–ATG12 complex. Rescue of SETD2 functions in the SETD2 deficiency in RCC cells, or reduction of SETD2 expression level in RCC cells wild type for this enzyme, demonstrates that SETD2 deficiency in RCC is directly involved in the acquisition of these alterations in the autophagic process. Furthermore, we revealed that deficiency in SETD2, known regulator of alternative splicing, is associated with increased expression of a short ATG12 spliced isoform at the depend of the canonical long ATG12 isoform in RCC cells. The defect in the ATG12-dependent conjugation system was found to be associated with a decrease autophagic flux, in accord with the role for this ubiquitin-like protein conjugation system in autophagosome formation and expansion. Finally, we report that SETD2 and ATG12 gene expression levels are associated with favorable respective unfavorable prognosis in ccRCC patients. Collectively, our findings bring further argument for considering the SETD2 gene status of ccRCC tumors, when therapeutic interventions, such as targeting the autophagic process, are considered to combat these kidney cancers.

Establishment of cohesion 1 homolog 2 facilitates cell aggressive behaviors and induces poor prognosis in renal cell carcinoma

Background and aims

Establishment of cohesion 1 homolog 2 (ESCO2) has been identified as an essential factor for cohesion in cell cycle in human multiple cancers. Nonetheless, its functional implication on prognosis and cellular behaviors of renal cell carcinoma (RCC) is rarely elucidated. We performed this study to detect the effects of ESCO2 in RCC progression.

Methods

We accessed The Cancer Genome Atlas (TCGA) database to evaluate the ESCO2 expression levels in tumor tissues, including 32 normal tissues and 289 tumor tissues. Quantitative real‐time PCR and Western blot were implemented for expression detection. After ESCO2 knockdown using siRNAs interference, functional experiments were conducted to explore the role of ESCO2, such as cell proliferation analysis and colony formation assay. Transwell assays for migration and invasion was also performed.

Results

In this study, ESCO2 was significantly increased in RCC tissues and cell lines. The RCC patients with high expression of ESCO2 were susceptible to unfavorable prognosis, and its expression has a marked association with clinical features containing age, gender, pathologic stage, and so on. Furthermore, knockdown of ESCO2 inhibited cell growth, invasion, and migration. Mechanistically, phosphorylation protein kinase B (AKT) and mammalian target of rapamycin (mTOR), proliferating cell nuclear antigen (PCNA), and p53 were all down‐regulated due to the ESCO2 inhibition.

Conclusions

Therefore, our results raised the possibility that ESCO2 may act as a promising option for tumor therapeutic interference by exhibiting enhanced selectivity over conventional chemotherapy.

Overexpressed miR-122-5p Promotes Cell Viability, Proliferation, Migration And Glycolysis Of Renal Cancer By Negatively Regulating PKM2

Objective

Renal cancer is one of the most deadly urological malignancies. Currently, there is still a lack of effective treatment. Our purpose was to explore the mechanisms of miR-122-5p in renal cancer.

Methods

The expression levels of miR-122-5p and pyruvate kinase M2 (PKM2) in renal cancer cells were detected by RT-qPCR and Western blot analyses, respectively. Then, we measured the cell viability after knockdown of miR-122-5p and PKM2 using CCK-8 assay. Moreover, flow cytometry was used to investigate cell cycle and apoptosis of renal cancer cells. The cell migration of renal cancer cells transfected by miR-122-5p inhibitor and siPKM2 was then detected by wound healing assay. Furthermore, glucose consumption and lactate production were measured. Autophagy-related protein LCII/I was detected by Western blot.

Results

MiR-122-5p was upregulated in renal cancer cells compared to HK2 cells, especially in 786-O cells. We found that silencing miR-122-5p promoted PKM2 expression in 786-O cells. After transfection of siPKM2 or miR-122-5p inhibitor, the cell viability of 786-O cells was significantly reduced. Furthermore, the G1 phase of 786-O cells was significantly blocked, and the S phase was significantly increased. In addition, knockdown of miR-122-5p or PKM2 promoted renal cancer cell apoptosis and inhibited cell migration. Glucose consumption of 786-O cells was significantly increased after transfection by siPKM2. Silencing miR-122-5p significantly promoted the expression levels of LCII/I.

Conclusion

Our findings revealed that overexpressed miR-122-5p promotes renal cancer cell viability, proliferation, migration, glycolysis and autophagy by negatively regulating PKM2, which provide a new insight for the development of renal cancer therapy.

Long noncoding RNA lnc-DILC stabilizes PTEN and suppresses clear cell renal cell carcinoma progression

Background

Increasing evidence has indicated that long noncoding RNAs (lncRNAs) are crucial regulators affecting the progression of human cancers. Recently, lncRNA downregulated in liver cancer stem cells (lnc-DILC) was identified to function as a tumor suppressor inhibiting the tumorigenesis and metastasis in liver cancer and colorectal cancer. However, to date, little is known about the functional roles of lnc-DILC in modulating malignant phenotypes of clear cell renal cell carcinoma (ccRCC) cells.

Methods

lnc-DILC expression in human ccRCC tissues was detected by qRT-PCR. Overexpression and knockdown experiments were carried out to determine the effects of lnc-DILC on ccRCC cell proliferation, migration and invasion. To reveal the underlying mechanisms of lnc-DILC functions in ccRCC cells. RNA immunoprecipitation, RNA pull-down, in vivo ubiquitination, co-immunoprecipitation and western blot assays were performed.

Results

Here, we identified that lnc-DILC levels were dramatically downregulated in ccRCC tissues. Loss of lnc-DILC expression was correlated with larger tumor size, advanced tumor grade and lymph node metastasis, and also predicted worse prognosis in patients with ccRCC. Functionally, knockdown and overexpression experiments demonstrated that lnc-DILC inhibited cell proliferation, migration and invasion in ccRCC cells. Mechanistic investigation revealed that lnc-DILC bound to tumor suppressor PTEN and suppressed its degradation. lnc-DILC repressed the PTEN ubiquitination through blocking the interaction between PTEN and E3 ubiquitin ligase WWP2 and recruiting the deubiquitinase USP11 to PTEN. Moreover, we demonstrated that PTEN–AKT signaling was crucial for lnc-DILC-mediated suppressive effects.

Conclusions

In summary, our research revealed a novel mechanism by which lnc-DILC regulates PTEN stability via WWP2 and USP11, and shed light on potential therapeutic strategies by the restoration of lnc-DILC expression in patients with ccRCC.