Molecular Mechanisms of Resistance to Immunotherapy and Antiangiogenic Treatments in Clear Cell Renal Cell Carcinoma

Preoperative neoadjuvant targeted therapy remodels intra-tumoral heterogeneity of clear-cell renal cell carcinoma and ferroptosis inhibition induces resistance progression

Neoadjuvant tyrosine kinase inhibitor (TKI) therapy is an important treatment option for advanced renal cell carcinoma (RCC). Many RCC patients may fail to respond or be resistant to TKI therapy. We aimed to explore the key mechanisms of neoadjuvant therapy résistance. We obtained tumor samples from matched pre-treatment biopsy and post-treatment surgical samples and performed single-cell RNA sequencing. Sunitinib-resistant ccRCC cell lines were established. Ferroptosis was detected by ferrous ion and lipid peroxidation levels. Tumor growth and resistance to Sunitinib was validated in vitro and vivo. Immunohistochemistry was used to validate the levels key genes and lipid peroxidation. Multi-center cohorts were included, including TCGA, ICGC, Checkmate-025 and IMmotion151 clinical trial. Survival analysis was performed to identify the associated clinical and genomic variables. Intratumoral heterogeneity was first described in the whole neoadjuvant management. The signature of endothelial cells was correlated with drug sensitivity and progression-free survival. Ferroptosis was shown to be the key biological program in malignant cell resistance. We observed tissue lipid peroxidation was negatively correlated with IL6 and tumor response. TKI-resistant cell line was established. SLC7A11 knockdown promoted cell growth and lipid peroxidation, increased the ferroptosis level, and suppressed the growth of tumor xenografts significantly (P < 0.01). IL6 could reverse the ferroptosis and malignant behavior caused by SLC7A11 (-) via JAK2/STAT3 pathway, which was rescued by the ferroptosis inducer Erastin. Our data indicate that ferroptosis is a novel strategy for advanced RCC treatment, which activated by IL6, providing a new idea for resistance to TKIs.

A Model to Predict Prognosis of Renal Cell Clear Cell Carcinoma Based on 3 Angiogenesis-related Long Non-coding RNAs

Background: Tumor angiogenesis is closely related to the progression of clear cell renal cell carcinoma (ccRCC). Long non-coding RNAs (lncRNAs) regulating angiogenesis could be potential biomarkers for predicting ccRCC prognosis. With this study, we aimed to construct a prognostic model based on lncRNAs and explore its underlying mechanisms. Methods: RNA data and clinical information were obtained from The Cancer Genome Atlas (TCGA) database. Angiogenesis-related genes (ARGs) were extracted from the Molecular Signatures database. Pearson correlation and LASSO and COX regression analyses were performed to identify survival-related AR-lncRNAs (sAR-lncRNAs) and construct a prognostic model. The predictive power of the prognostic model was verified according to Kaplan‒Meier curve, receiver operating characteristic (ROC) curve and nomogram analyses. The correlation between the prognostic model and clinicopathological characteristics was assessed via univariate and multivariate analyses. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis was subsequently performed to elucidate the mechanisms of the sAR-lncRNAs. In vitro qPCR, immunohistochemistry, migration and invasion assays were conducted to confirm the angiogenic function of sAR-lncRNAs. Results: Three sAR-lncRNAs were used to construct a prognostic model. The model was moderately accurate in predicting 1- , 3- and 5-year ccRCC prognosis, and the risk score according to this model was closely related to clinicopathological characteristics such as T grade and T stage. A nomogram was constructed to precisely estimate the overall survival of ccRCC patients. KEGG enrichment analysis indicated that the MAPK and Notch pathways were highly enriched in high-risk patients. Additionally, we found that the expression of the lncRNAs AC005324.4 and AC104964.4 in the prognostic model was lower in ccRCC cell lines and cancer tissues than in the HK-2 cell line and paracancerous tissues, while the expression of the lncRNA AC087482.1 showed the opposite trend. In a coculture model, knockdown of lncRNA AC005324.4 and lncRNA AC104964.4 significantly promoted the migration and invasion of human umbilical vein endothelial cells (HUVECs), but siR-AC087482.1 transfection alleviated these effects. Conclusions: We constructed a prognostic model based on 3 sAR-lncRNAs and validated its value in clinicopathological characteristics and prognostic prediction of ccRCC patients, providing a new perspective for ccRCC treatment decision making.

CDCA5-EEF1A1 interaction promotes progression of clear cell renal cell carcinoma by regulating mTOR signaling

BACKGROUND

Cell division cycle associated 5 (CDCA5) plays ontogenetic role in various human cancers. However, its specific function and regulatory mechanism in ccRCC remain uncertain.

METHODS

Immunohistochemistry and western blots were performed to investigate the expression of CDCA5 in ccRCC tissues. Genetic knockdown and upregulation of CDCA5 were performed to investigate its functional roles in ccRCC proliferation, migration, apoptosis and sunitinib resistance. Furthermore, Co-IP assay and LC-MS/MS were performed to investigate the underlying mechanisms.

RESULTS

We found that CDCA5 expression is frequently upregulated in ccRCC tumors and is associated with poor prognosis of ccRCC patients. Functionally, CDCA5 promotes proliferation, migration, and sunitinib resistance, while inhibiting apoptosis in ccRCC cells. In vivo mouse xenograft model confirms that silencing of CDCA5 drastically inhibits the growth of ccRCC. Mechanistically, we discovered that CDCA5 interacts with Eukaryotic Translation Elongation Factor 1 Alpha 1 (EEF1A1) to regulate mTOR signaling pathway, thereby promoting ccRCC progression.

CONCLUSIONS

Taken together, our results demonstrate the significant role of CDCA5 in ccRCC progression. The findings may provide insights for the development of new treatment strategies targeting CDCA5 for ccRCC patients.

Exosomes in renal cell carcinoma: challenges and opportunities

Renal cell carcinoma (RCC) is the most common type of kidney cancer that accounts for approximately 2-3% of adult malignancies. Among the primary treatment methods for this type of cancer are surgery and targeted treatment. Still, due to less than optimal effectiveness, there are problems such as advanced distant metastasis, delayed diagnosis, and drug resistance that continue to plague patients. In recent years, therapeutic advances have increased life expectancy and effective treatment in renal cell carcinoma patients. One of these methods is the use of stem cells. Although the therapeutic effects of stem cells, especially mesenchymal stem cells, are still impressive, today, extracellular vesicles (EVs) as carrying molecules and various mediators in intercellular communications, having a central role in tumorigenesis, metastasis, immune evasion, and drug response, and on the other hand, due to its low immunogenicity and strong regulatory properties of the immune system, has received much attention from researchers and doctors. Despite the increasing interest in exosomes as the most versatile type of EVs, the heterogeneity of their efficacy presents challenges and, on the other hand, exciting opportunities for diagnostic and clinical interventions.In the upcoming article, we will review the various aspects of exosomes' effects in the prevention, treatment, and progress of renal cell carcinoma and also ways to optimize them to strengthen their positive sides.

Machine learning-driven prognostic analysis of cuproptosis and disulfidptosis-related lncRNAs in clear cell renal cell carcinoma: a step towards precision oncology

Cuproptosis and disulfidptosis, recently discovered mechanisms of cell death, have demonstrated that differential expression of key genes and long non-coding RNAs (lncRNAs) profoundly influences tumor development and affects their drug sensitivity. Clear cell renal cell carcinoma (ccRCC), the most common subtype of kidney cancer, presently lacks research utilizing cuproptosis and disulfidptosis-related lncRNAs (CDRLRs) as prognostic markers. In this study, we analyzed RNA-seq data, clinical information, and mutation data from The Cancer Genome Atlas (TCGA) on ccRCC and cross-referenced it with known cuproptosis and disulfidptosis-related genes (CDRGs). Using the LASSO machine learning algorithm, we identified four CDRLRs-ACVR2B-AS1, AC095055.1, AL161782.1, and MANEA-DT-that are strongly associated with prognosis and used them to construct a prognostic risk model. To verify the model's reliability and validate these four CDRLRs as significant prognostic factors, we performed dataset grouping validation, followed by RT-qPCR and external database validation for differential expression and prognosis of CDRLRs in ccRCC. Gene function and pathway analysis were conducted using Gene Ontology (GO) and Gene Set Enrichment Analysis (GSEA) for high- and low-risk groups. Additionally, we have analyzed the tumor mutation burden (TMB) and the immune microenvironment (TME), employing the oncoPredict and Immunophenoscore (IPS) algorithms to assess the sensitivity of diverse risk categories to targeted therapeutics and immunosuppressants. Our predominant objective is to refine prognostic predictions for patients with ccRCC and inform treatment decisions by conducting an exhaustive study on cuproptosis and disulfidptosis.

MUC1 Drives the Progression and Chemoresistance of Clear Cell Renal Carcinomas

While the transmembrane glycoprotein mucin 1 (MUC1) is clustered at the apical borders of normal epithelial cells, with transformation and loss of polarity, MUC1 is found at high levels in the cytosol and is uniformly distributed over the entire surface of carcinoma cells, where it can promote tumor progression and adversely affects the response to therapy. Clear cell renal cell carcinoma (ccRCC), the main histotype of kidney cancer, is typically highly resistant to conventional and targeted therapies for reasons that remain largely unknown. In this context, we investigated whether MUC1 also plays a pivotal role in the cellular and molecular events driving ccRCC progression and chemoresistance. We showed, using loss- and gain-of-function approaches in ccRCC-derived cell lines, that MUC1 not only influences tumor progression but also induces a multi-drug-resistant profile reminiscent of the activation of ABC drug efflux transporters. Overall, our results suggest that targeting MUC1 may represent a novel therapeutic approach to limit ccRCC progression and improve drug sensitivity.

Emerging Immunotherapy Approaches for Advanced Clear Cell Renal Cell Carcinoma

The most common subtype of renal cell carcinoma is clear cell renal cell carcinoma (ccRCC). While localized ccRCC can be cured with surgery, metastatic disease has a poor prognosis. Recently, immunotherapy has emerged as a promising approach for advanced ccRCC. This review provides a comprehensive overview of the evolving immunotherapeutic landscape for metastatic ccRCC. Immune checkpoint inhibitors (ICIs) like PD-1/PD-L1 and CTLA-4 inhibitors have demonstrated clinical efficacy as monotherapies and in combination regimens. Combination immunotherapies pairing ICIs with antiangiogenic agents, other immunomodulators, or novel therapeutic platforms such as bispecific antibodies and chimeric antigen receptor (CAR) T-cell therapy are areas of active research. Beyond the checkpoint blockade, additional modalities including therapeutic vaccines, cytokines, and oncolytic viruses are also being explored for ccRCC. This review discusses the mechanisms, major clinical trials, challenges, and future directions for these emerging immunotherapies. While current strategies have shown promise in improving patient outcomes, continued research is critical for expanding and optimizing immunotherapy approaches for advanced ccRCC. Realizing the full potential of immunotherapy will require elucidating mechanisms of response and resistance, developing predictive biomarkers, and rationally designing combination therapeutic regimens tailored to individual patients. Advances in immunotherapy carry immense promise for transforming the management of metastatic ccRCC.

Cuproptosis and its application in different cancers: an overview

Heavy metal ions are essential micronutrients for human health. They are also indispensable to maintaining health and regular operation of organs. Increasing or decreasing these metal ions will lead to cell death, such as ferroptosis. Tsvetkov et al. have recently proposed a novel cell death method called "Cuproptosis". Many researchers have linked this form of death to the diagnosis, prognosis, microenvironment infiltration, and prediction of immunotherapeutic efficacy of various tumors to better understand these tumors. Similarly, with the proposal of this mechanism, the killing effect of copper ionophores on cancer cells has come to our attention again. We introduced the mechanism of cuproptosis in detail and described the establishment of the corresponding prognostic model and risk score for uveal melanoma through cuproptosis. In addition, we describe the current progress in the study of cancer in other organs through cuproptosis and summarize the treatment of tumours by copper ionophore and its future research direction. With further research, the concept of cuproptosis may help us understand cancer and guide its clinical treatment.

[Mechanism of nuclear protein 1 in the resistance to axitinib in clear cell renal cell carcinoma]

OBJECTIVE

To explore the potential mechanism of resistance to axitinib in clear cell renal cell carcinoma (ccRCC), with a view to expanding the understanding of axitinib resistance, facilitating the design of more specific treatment options, and improving the treatment effectiveness and survival prognosis of patients.

METHODS

By exploring the half maximum inhibitory concentration (IC50) of axitinib on ccRCC cell lines 786-O and Caki-1, cell lines resistant to axitinib were constructed by repeatedly stimulated with axitinib at this concentration for 30 cycles in vitro. Cell lines that were not treated by axitinib were sensitive cell lines. The phenotypic differences of cell proliferation and apoptosis levels between drug resistant and sensitive lines were tested. Genes that might be involved in the drug resistance process were screened from the differentially expressed genes that were co-upregulated in the two drug resistant lines by transcriptome sequencing. The expression level of the target gene in the drug resistant lines was verified by real-time quantitative polymerase chain reaction (RT-qPCR) and Western blot (WB). The expression differences of the target gene in ccRCC tumor tissues and adjacent tissues were analyzed in the Gene Expression Profiling Interactive Analysis (GEPIA) public database, and the impact of the target gene on the prognosis of ccRCC patients was analyzed in the Kaplan-Meier Plotter (K-M Plotter) database. After knocking down the target gene in the drug resistant lines using RNA interference by lentivirus vector, the phenotypic differences of the cell lines were tested again. WB was used to detect the levels of apoptosis-related proteins in the different treated cell lines to find molecular pathways that might lead to drug resistance.

RESULTS

Cell lines 786-O-R and Caki-1-R resistant to axitinib were successfully constructed in vitro, and their IC50 were significantly higher than those of the sensitive cell lines (10.99 μmol/L, P < 0.01; 11.96 μmol/L, P < 0.01, respectively). Cell counting kit-8 (CCK-8) assay, colony formation, and 5-ethynyl-2 '-deoxyuridine (EdU) assay showed that compared with the sensitive lines, the proliferative ability of the resistant lines decreased, but apoptosis staining showed a significant decrease in the level of cell apoptosis of the resistant lines (P < 0.01). Although resistant to axitinib, the resistant lines had no obvious new replicated cells in the environment of 20 μmol/L axitinib. Nuclear protein 1 (NUPR1) gene was screened by transcriptome sequencing, and its RNA (P < 0.0001) and protein expression levels significantly increased in the resistant lines. Database analysis showed that NUPR1 was significantly overexpressed in ccRCC tumor tissue (P < 0.05); the ccRCC patients with higher expression ofNUPR1had a worse survival prognosis (P < 0.001). Apoptosis staining results showed that knockdown ofNUPR1inhibited the anti-apoptotic ability of the resistant lines to axitinib (786-O, P < 0.01; Caki-1, P < 0.05). WB results showed that knocking downNUPR1decreased the protein level of B-cell lymphoma-2 (BCL2), increased the protein level of BCL2-associated X protein (BAX), decreased the protein level of pro-caspase3, and increased the level of cleaved-caspase3 in the resistant lines after being treated with axitinib.

CONCLUSION

ccRCC cell lines reduce apoptosis through theNUPR1 -BAX/ BCL2 -caspase3 pathway, which is involved in the process of resistance to axitinib.

Hyperthermia inhibits cellular function and induces immunogenic cell death in renal cell carcinoma

BACKGROUND

In recent years, hyperthermia has been widely applied as a novel strategy for cancer treatment due to its multiple antitumour effects. In particular, the potential influences of hyperthermia on the tumour immune microenvironment may improve the efficacy of immunotherapies. However, the effect of hyperthermia on renal cell carcinoma (RCC) has not been well characterized until now.

METHODS

In the present study, we primarily evaluated the effects of hyperthermia on cellular function via cellular proliferation, migration, invasion and apoptosis assays. In addition, the influence of hyperthermia on the immunogenicity of RCC cells was analysed using flow cytometry analysis, enzyme-linked immunosorbent assays, and immunofluorescent (IF) staining.

RESULTS

Our results demonstrate that hyperthermia significantly inhibits RCC cell proliferation, migration, and invasion and promotes cell apoptosis. In addition, we verified that hyperthermia improves the immunogenicity of RCC cells by inducing immunogenic cell death.

CONCLUSION

Our findings suggest that hyperthermia is a promising therapeutic strategy for RCC.

Mapping the tumor microenvironment in clear cell renal carcinoma by single-cell transcriptome analysis

Introduction: Clear cell renal cell carcinoma (ccRCC) is associated with unfavorable clinical outcomes. To identify viable therapeutic targets, a comprehensive understanding of intratumoral heterogeneity is crucial. In this study, we conducted bioinformatic analysis to scrutinize single-cell RNA sequencing data of ccRCC tumor and para-tumor samples, aiming to elucidate the intratumoral heterogeneity in the ccRCC tumor microenvironment (TME). Methods: A total of 51,780 single cells from seven ccRCC tumors and five para-tumor samples were identified and grouped into 11 cell lineages using bioinformatic analysis. These lineages included tumor cells, myeloid cells, T-cells, fibroblasts, and endothelial cells, indicating a high degree of heterogeneity in the TME. Copy number variation (CNV) analysis was performed to compare CNV frequencies between tumor and normal cells. The myeloid cell population was further re-clustered into three major subgroups: monocytes, macrophages, and dendritic cells. Differential expression analysis, gene ontology, and gene set enrichment analysis were employed to assess inter-cluster and intra-cluster functional heterogeneity within the ccRCC TME. Results: Our findings revealed that immune cells in the TME predominantly adopted an inflammatory suppression state, promoting tumor cell growth and immune evasion. Additionally, tumor cells exhibited higher CNV frequencies compared to normal cells. The myeloid cell subgroups demonstrated distinct functional properties, with monocytes, macrophages, and dendritic cells displaying diverse roles in the TME. Certain immune cells exhibited pro-tumor and immunosuppressive effects, while others demonstrated antitumor and immunostimulatory properties. Conclusion: This study contributes to the understanding of intratumoral heterogeneity in the ccRCC TME and provides potential therapeutic targets for ccRCC treatment. The findings emphasize the importance of considering the diverse functional roles of immune cells in the TME for effective therapeutic interventions.

High C1QTNF1 expression mediated by potential ncRNAs is associated with poor prognosis and tumor immunity in kidney renal clear cell carcinoma

Background: Kidney renal clear cell carcinoma (KIRC) originates from proximal tubular cells and is the most common subtype of renal cell carcinoma. KIRC is characterized by changes in lipid metabolism, and obesity is a risk factor for it. C1q And TNF Related 1 (C1QTNF1), a novel adipokine and member of the C1q and TNF-related protein (CTRP) family, has been shown to affect the progression of various cancers. However, the role of C1QTNF1 in KIRC has not been studied. Methods: The Wilcoxon rank sum test was used to analyze the expression of C1QTNF1 in KIRC tissues and normal tissues. The relationship between clinicopathological features and C1QTNF1 levels was also examined by logistic regression and the Wilcoxon rank sum test. In addition, the effect of C1QTNF1 on the prognosis of KIRC patients was analyzed by Kaplan-Meier (KM). The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to analyze the potential signaling pathways and biological functions of differential genes. A nomogram was constructed to predict the prognosis of KIRC patients. Spearman correlation analysis was performed to determine the association between C1QTNF1 expression and immune cell infiltration and immune checkpoint genes. The upstream miRNAs and lncRNAs of C1QTNF1 were predicted by the ENCORI online tool. Finally, we examined the proliferation, invasion, and migration abilities of KIRC cells after C1QTNF1 knockdown. Results: The expression of C1QTNF1 in KIRC tissues was significantly higher than in normal renal tissues. Patients with higher C1QTNF1 expression had a poor prognosis, a finding supported by Kaplan-Meier survival analysis. C1QTNF1 expression was significantly correlated with TNM and pathologic stages, age, and gender (p < 0.05). The C1QTNF1 expression level was significantly correlated with immune cell infiltration and immune checkpoint genes in KIRC. Additionally, high C1QTNF1 expression was associated with poor prognosis in stage I and II, T1 and T2, T3 and T4, N0, and M0 patients (HR > 1, p < 0.05). The calibration diagram shows that the C1QTNF1 model has effective predictive performance for the survival of KIRC patients. Knockdown of C1QTNF1 inhibited KIRC cell proliferation, cell migration, and cell invasion. In addition, CYTOR and AC040970.1/hsa-miR-27b-3p axis were identified as the most likely upstream ncRNA-related pathways of C1QTNF1 in KIRC. Conclusion: In conclusion, our study suggests that high expression of C1QTNF1 is associated with KIRC progression and immune infiltration. The increased expression of C1QTNF1 suggests a poor prognosis in KIRC patients.

Dyskerin and telomerase RNA component are sex-differentially associated with outcomes and Sunitinib response in patients with clear cell renal cell carcinoma

BACKGROUND

Clear cell renal cell carcinoma (ccRCC) displays sex-biased incidence, outcomes, molecular alterations and treatment efficacy; however, clinical managements are largely identical in male and female patients. Moreover, many biomarkers have been identified as predictors for ccRCC outcomes and response to therapeutic drugs, such as multitargeted tyrosine-kinase receptor (TKR) inhibitors, but little is known about their sex-specificity. Dyskerin (DKC1), encoded by the DKC1 gene within Xq28, is a telomerase co-factor stabilizing telomerase RNA component (TERC) and overexpressed in various cancers. Here, we determined whether DKC1 and/or TERC affect ccRCC sex-differentially.

METHODS

DKC1 and TERC expression in primary ccRCC tumors was assessed using RNA sequencing and qPCR. DKC1 association with molecular alterations and overall or progression-free survival (OS or PFS) was analyzed in the TCGA cohort of ccRCC. The IMmotion 151 and 150 ccRCC cohorts were analyzed to evaluate impacts of DKC1 and TERC on Sunitinib response and PFS.

RESULTS

DKC1 and TERC expression was significantly upregulated in ccRCC tumors. High DKC1 expression predicts shorter PFS independently in female but not male patients. Tumors in the female DKC1-high group exhibited more frequent alterations in PIK3CA, MYC and TP53 genes. Analyses of the IMmotion 151 ccRCC cohort treated with the TKR inhibitor Sunitinib showed that female patients in the DKC1-high group was significantly associated with lower response rates (P = 0.021) accompanied by markedly shortened PFS (6.1 vs 14.2 months, P = 0.004). DKC1 and TERC expression correlated positively with each other, and higher TERC expression predicted poor Sunitinib response (P = 0.031) and shorter PFS (P = 0.004), too. However, DKC1 rather than TERC acted as an independent predictor (P < 0.001, HR = 2.0, 95% CI 1.480-2.704). In male patients, DKC1 expression was associated with neither Sunitinib response (P = 0.131) nor PFS (P = 0.184), while higher TERC levels did not predict response rates. Similar results were obtained from the analysis of the Sunitinib-treated IMmotion 150 ccRCC patients.

CONCLUSIONS

DKC1 serves as an independent female-specific predictor for survival and Sunitinib efficacy in ccRCC, which contribute to better understanding of the sex-biased ccRCC pathogenesis and improve personalized interventions of ccRCC.

A cisplatin conjugate with tumor cell specificity exhibits antitumor effects in renal cancer models

BACKGROUND

Clear cell renal cell carcinoma (ccRCC) is the most common type of kidney cancer and is notorious for its resistance to both chemotherapy and small-molecule inhibitor targeted therapies. Subcellular targeted cancer therapy may thwart the resistance to produce a substantial effect.

METHODS

We tested whether the resistance can be circumvented by subcellular targeted cancer therapy with DZ-CIS, which is a chemical conjugate of the tumor-cell specific heptamethine carbocyanine dye (HMCD) with cisplatin (CIS), a chemotherapeutic drug with limited use in ccRCC treatment because of frequent renal toxicity.

RESULTS

DZ-CIS displayed cytocidal effects on Caki-1, 786-O, ACHN, and SN12C human ccRCC cell lines and mouse Renca cells in a dose-dependent manner and inhibited ACHN and Renca tumor formation in experimental mouse models. Noticeably, in tumor-bearing mice, repeated DZ-CIS use did not cause renal toxicity, in contrast to the CIS-treated control animals. In ccRCC tumors, DZ-CIS treatment inhibited proliferation markers but induced cell death marker levels. In addition, DZ-CIS at half maximal inhibitory concentration (IC50) sensitized Caki-1 cells to small-molecule mTOR inhibitors. Mechanistically, DZ-CIS selectively accumulated in ccRCC cells' subcellular organelles, where it damages the structure and function of mitochondria, leading to cytochrome C release, caspase activation, and apoptotic cancer cell death.

CONCLUSIONS

Results from this study strongly suggest DZ-CIS be tested as a safe and effective subcellular targeted cancer therapy.

Revisiting mechanisms of resistance to immunotherapies in metastatic clear-cell renal-cell carcinoma

Renal-cell carcinoma (RCC) remains a leading cause of cancer-related mortality worldwide. Though newer therapeutic combinations of immune checkpoint inhibitors and targeted therapies have greatly improved outcomes, resistance to these therapies is becoming a challenge for long-term control. Mechanisms of resistance have been explored in a variety of solid tumors, including RCC. Based upon our review of the current literature on the mechanisms of resistance to immunotherapies for the management of metastatic clear-cell renal cell carcinomas (mccRCC), the ensuing conclusions have been made: The management of mccRCC has progressed substantially with the advent of checkpoint inhibitors and targeted oral therapies, alone and/or in combination. Nevertheless, innate or developed resistance to these therapies remains an ongoing challenge, particularly to immune checkpoint inhibitors (ICIs). Several of the known mechanisms of resistance have been well defined, but recent progression in cellular therapies helps to expand the armamentarium of potential combination options that may overcome these modes of resistance and improve long-term disease control and survival for an otherwise dismal disease. In the ensuing review and update of the literature on the mechanisms of resistance to immunotherapies in mccRCC, we have revisited the known resistance mechanisms of immunotherapies in metastatic clear-cell RCC and explored ongoing and future strategies to overcome them.

Tumor infiltrating lymphocytes and radiological picture of the tumor

Tumor microenvironment (TME) is a complex entity that includes besides the tumor cells also a whole range of immune cells. Among various populations of immune cells infiltrating the tumor, tumor infiltrating lymphocytes (TILs) are a population of lymphocytes characterized by high reactivity against the tumor component. As, TILs play a key role in mediating responses to several types of therapy and significantly improve patient outcomes in some cancer types including for instance breast cancer and lung cancer, their assessment has become a good predictive tool in the evaluation of potential treatment efficacy. Currently, the evaluation of the density of TILs infiltration is performed by histopathological. However, recent studies have shed light on potential utility of several imaging methods, including ultrasonography, magnetic resonance imaging (MRI), positron emission tomography-computed tomography (PET-CT), and radiomics, in the assessment of TILs levels. The greatest attention concerning the utility of radiology methods is directed to breast and lung cancers, nevertheless imaging methods of TILs are constantly being developed also for other malignancies. Here, we focus on reviewing the radiological methods used to assess the level of TILs in different cancer types and on the extraction of the most favorable radiological features assessed by each method.

BAP1 and PTEN mutations shape the immunological landscape of clear cell renal cell carcinoma and reveal the intertumoral heterogeneity of T cell suppression: a proof-of-concept study

Clear cell renal cell carcinoma (ccRCC) is an immunologically vulnerable tumor entity, and immune checkpoint inhibitors are now widely used to treat patients with advanced disease. Whether and to what extent immune responses in ccRCC are shaped by genetic alterations, however, is only beginning to emerge. In this proof-of-concept study, we performed a detailed correlative analysis of the mutational and immunological landscapes in a series of 23 consecutive kidney cancer patients. We discovered that a high infiltration with CD8 + T cells was not dependent on the number of driver mutations but rather on the presence of specific mutational events, namely pathogenic mutations in PTEN or BAP1. This observation encouraged us to compare mechanisms of T cell suppression in the context of four different genetic patterns, i.e., the presence of multiple drivers, a PTEN or BAP1 mutation, or the absence of detectable driver mutations. We found that ccRCCs harboring a PTEN or BAP1 mutation showed the lowest level of Granzyme B positive tumor-infiltrating lymphocytes (TILs). A multiplex immunofluorescence analysis revealed a significant number of CD8 + TILs in the vicinity of CD68 + macrophages/monocytes in the context of a BAP1 mutation but not in the context of a PTEN mutation. In line with this finding, direct interactions between CD8 + TILs and CD163 + M2-polarized macrophages were found in BAP1-mutated ccRCC but not in tumors with other mutational patterns. While an absence of driver mutations was associated with more CD8 + TILs in the vicinity of FOXP3 + Tregs and CD68 + monocytes/macrophages, the presence of multiple driver mutations was, to our surprise, not found to be strongly associated with immunosuppressive mechanisms. Our results highlight the role of genetic alterations in shaping the immunological landscape of ccRCC. We discovered a remarkable heterogeneity of mechanisms that can lead to T cell suppression, which supports the need for personalized immune oncological approaches.

High VSX1 expression promotes the aggressiveness of clear cell renal cell carcinoma by transcriptionally regulating FKBP10

BACKGROUND

Clear cell renal cell carcinoma (ccRCC), the most common urological malignancy, has an unfavorable prognosis and an unknown mechanism of progression. Through survival analyses screening of The Cancer Genome Atlas (TCGA) dataset, we identified Visual system homeobox1 (VSX1) as a novel potential prognostic biomarker in ccRCC and subsequently investigated the oncogenic role of VSX1 in ccRCC.

METHODS

The differential expression of VSX1 in human tumors and the clinical prognoses were analyzed in the TCGA dataset and Gene Expression Omnibus. Spearman's correlation coefficient was determined for the correlation analysis of VSX1 expression and other genes of interest. The roles of VSX1 in cell proliferation, invasion, and migration of ccRCC cells were evaluated via the CCK-8 assay, colony formation assay, and Transwell assay, respectively. Further results were demonstrated by western blotting, immunohistochemistry, qRT-PCR, tumor sphere formation, flow cytometry, and the dual‑luciferase reporter assay.

RESULTS

VSX1 mRNA upregulation was generally observed in multiple human malignancies from the TCGA database and was confirmed in ccRCC clinical specimens from our department. High VSX1 expression usually indicated that overall and disease-free survival were unfavorable for patients with ccRCC. In terms of mechanism, knockdown or overexpression of VSX1 affected ccRCC aggressiveness in vitro. The dual-luciferase reporter gene assay implied that VSX1 overexpression significantly increased the luciferase activity of TMEM44, FKBP10, and TRIB3, which indicated that VSX1 promoted ccRCC invasiveness via transcriptional regulation of these genes. The significantly enhanced growth in vitro that was induced by stable VSX1 overexpression was almost restored to normal by the knockdown of FKBP10.

CONCLUSIONS

This study demonstrated that VSX1 was a novel prognostic biomarker in ccRCC and that high VSX1 expression promoted cell proliferation, invasion, and migration in ccRCC via transcriptional activation of downstream target genes.

Treatment of Refractory Metastatic Renal Cell Carcinoma

First-line treatment for metastatic renal cell carcinoma (mRCC) rapidly shifted in recent years with the advent of combination therapies, including immune checkpoint inhibitor (ICI) doublets and combinations of an ICI with a vascular endothelial growth factor receptor (VEGFR) targeted tyrosine kinase inhibitor (TKI). Despite improvements in overall survival and many durable responses, there exists a significant number of patients who fail to respond to these agents, and many patients eventually progress. Given the rapid changes in the front-line setting, it is essential to understand treatment options in refractory mRCC. Here, we review the evidence behind current options for later-line therapies, often involving additional VEGFR-TKIs alone or in combination with mammalian target of rapamycin (mTOR) targeted agents, as well as situations where consideration of immunotherapy rechallenge may be appropriate. Additionally, we describe ongoing clinical trials examining concurrent ICI and TKI in the refractory setting, as well as those studying novel agents, such as targeted drug-antibody conjugates and hypoxia inducible factor 2α (HIF-2α) inhibitors. Finally, we review considerations for non-clear cell histologies in the refractory setting and mechanisms of resistance in mRCC.

The cuproptosis-associated 13 gene signature as a robust predictor for outcome and response to immune- and targeted-therapies in clear cell renal cell carcinoma

Cuproptosis, the newly identified form of regulatory cell death (RCD), results from mitochondrial proteotoxic stress mediated by copper and FDX1. Little is known about significances of cuproptosis in oncogenesis. Here we determined clinical implications of cuproptosis in clear cell renal cell carcinoma (ccRCC). Based on the correlation and survival analyses of cuproptosis-correlated genes in TCGA ccRCC cohort, we constructed a cuproptosis-associated 13 gene signature (CuAGS-13) score system. In both TCGA training and two validation cohorts, when patients were categorized into high- and low-risk groups according to a median score as the cutoff, the CuAGS-13 high-risk group was significantly associated with shorter overall survival (OS) and/or progression-free survival (PFS) independently (P<0.001 for all). The CuAGS-13 score assessment could also predict recurrence and recurrence-free survival of patients at stage I - III with a high accuracy, which outperformed the ccAccB/ClearCode34 model, a well-established molecular predictor for ccRCC prognosis. Moreover, patients treated with immune checkpoint inhibitors (ICIs) acquired complete/partial remissions up to 3-time higher coupled with significantly longer PFS in the CuAGS-13 low- than high-risk groups in both training and validation cohorts of ccRCCs (7.2 - 14.1 vs. 2.1 - 3.0 months, P<0.001). The combination of ICI with anti-angiogenic agent Bevacizumab doubled remission rates in CuAGS-13 high-risk patients while did not improve the efficacy in the low-risk group. Further analyses showed a positive correlation between CuAGS-13 and TIDE scores. We also observed that the CuAGS-13 score assessment accurately predicted patient response to Sunitinib, and higher remission rates in the low-risk group led to longer PFS (Low- vs. high-risk, 13.9 vs. 5.8 months, P = 5.0e-12). Taken together, the CuAGS-13 score assessment serves as a robust predictor for survival, recurrence, and response to ICIs, ICI plus anti-angiogenic drugs and Sunitinib in ccRCC patients, which significantly improves patient stratifications for precision medicine of ccRCC.

Identification of EZH2 as Cancer Stem Cell Marker in Clear Cell Renal Cell Carcinoma and the Anti-Tumor Effect of Epigallocatechin-3-Gallate (EGCG)

Simple Summary

Cancer stem cells (CSCs) refer to a group of undifferentiated heterogeneous tumor cells, defined as capable of self-renewal, differentiation, and may be linked to therapeutic resistance and tumor relapse. The development of novel therapeutic strategies to target CSCs and the identification of typical CSC markers are essential to improve therapy efficacy and prevent tumor relapse. Our study identifies CSC markers in renal cell carcinoma (RCC) and explores a potential treatment strategy and the underlying pharmacological mechanisms.

Abstract

The aim of the study was to develop a new therapeutic strategy to target cancer stem cells (CSCs) in clear cell renal cell carcinoma (ccRCC) and to identify typical CSC markers to improve therapy effectiveness. It was found that the corrected-mRNA expression-based stemness index was upregulated in kidney renal clear cell carcinoma (KIRC) tissues compared to non-tumor tissue and increased with higher tumor stage and grade. EZH2 was identified as a CSC marker and prognosis factor for KIRC patients. The expression of EZH2 was associated with several activated tumor-infiltrating immune cells. High expression of EZH2 was enriched in immune-related pathways, low expression was related to several metabolic pathways. Epigallocatechin-3-gallate (EGCG) was identified as the most potent suppressor of EZH2, was able to inhibit viability, migration, and invasion, and to increase the apoptosis rate of ccRCC CSCs. KIF11, VEGF, and MMP2 were identified as predictive EGCG target genes, suggesting a potential mechanism of how EZH2 might regulate invasiveness and migration. The percentages of FoxP3+ Treg cells in the peripheral blood mononuclear cells of ccRCC patients decreased significantly when cultured with spheres pretreated with EGCG plus sunitinib compared to spheres without treatment. Our findings provide new insights into the treatment options of ccRCC based on targeting CSCs.

Crosstalk Between Metabolism and Immune Activity Reveals Four Subtypes With Therapeutic Implications in Clear Cell Renal Cell Carcinoma

Clear cell renal cell carcinoma (ccRCC) is characterized by metabolic dysregulation and distinct immunological signatures. The interplay between metabolic and immune processes in the tumor microenvironment (TME) causes the complexity and heterogeneity of immunotherapy responses observed during ccRCC treatment. Herein, we initially identified two distinct metabolic subtypes (C1 and C2 subtypes) and immune subtypes (I1 and I2 subtypes) based on the occurrence of differentially expressed metabolism-related prognostic genes and immune-related components. Notably, we observed that immune regulators with upregulated expression actively participated in multiple metabolic pathways. Therefore, we further delineated four immunometabolism-based ccRCC subtypes (M1, M2, M3, and M4 subtypes) according to the results of the above classification. Generally, we found that high metabolic activity could suppress immune infiltration. Immunometabolism subtype classification was associated with immunotherapy response, with patients possessing the immune-inflamed, metabolic-desert subtype (M3 subtype) that benefits the most from immunotherapy. Moreover, differences in the shifts in the immunometabolism subtype after immunotherapy were observed in the responder and non-responder groups, with patients from the responder group transferring to subtypes with immune-inflamed characteristics and less active metabolic activity (M3 or M4 subtype). Immunometabolism subtypes could also serve as biomarkers for predicting immunotherapy response. To decipher the genomic and epigenomic features of the four subtypes, we analyzed multiomics data, including miRNA expression, DNA methylation status, copy number variations occurrence, and somatic mutation profiles. Patients with the M2 subtype possessed the highest VHL gene mutation rates and were more likely to be sensitive to sunitinib therapy. Moreover, we developed non-invasive radiomic models to reveal the status of immune activity and metabolism. In addition, we constructed a radiomic prognostic score (PRS) for predicting ccRCC survival based on the seven radiomic features. PRS was further demonstrated to be closely linked to immunometabolism subtype classification, immune score, and tumor mutation burden. The prognostic value of the PRS and the association of the PRS with immune activity and metabolism were validated in our cohort. Overall, our study established four immunometabolism subtypes, thereby revealing the crosstalk between immune and metabolic activities and providing new insights into personal therapy selection.

A Double-Negative Feedback Interaction between miR-21 and PPAR-α in Clear Renal Cell Carcinoma

Clear cell renal cell carcinoma (ccRCC) is the main histotype of kidney cancer, which is typically highly resistant to conventional therapies and known for abnormal lipid accumulation. In this context, we focused our attention on miR-21, an oncogenic miRNA overexpressed in ccRCC, and peroxysome proliferator-activated receptor-α (PPAR- α), one master regulator of lipid metabolism targeted by miR-21. First, in a cohort of 52 primary ccRCC samples, using RT-qPCR and immunohistochemistry, we showed that miR-21 overexpression was correlated with PPAR-α downregulation. Then, in ACHN and 786-O cells, using RT-qPCR, the luciferase reporter gene, chromatin immunoprecipitation, and Western blotting, we showed that PPAR-α overexpression (i) decreased miR-21 expression, AP-1 and NF-κB transcriptional activity, and the binding of AP-1 and NF-κB to the miR-21 promoter and (ii) increased PTEN and PDCD4 expressions. In contrast, using pre-miR-21 transfection, miR-21 overexpression decreased PPAR-α expression and transcriptional activity mediated by PPAR-α, whereas the anti-miR-21 (LNA-21) strategy increased PPAR-α expression, but also the expression of its targets involved in fatty acid oxidation. In this study, we showed a double-negative feedback interaction between miR-21 and PPAR-α. In ccRCC, miR-21 silencing could be therapeutically exploited to restore PPAR-α expression and consequently inhibit the oncogenic events mediated by the aberrant lipid metabolism of ccRCC.