Resistance to Systemic Agents in Renal Cell Carcinoma Predict and Overcome Genomic Strategies Adopted by Tumor

TFE3/PI3K/Akt/mTOR Axis in Renal Cell Carcinoma Affects Tumor Microenvironment

The role of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway in renal cell carcinoma (RCC) progression, metastasis, and resistance to therapies has not been investigated thoroughly. Transcription factor E3 (TFE3) expression is related to a poorer prognosis and tumor microenvironment in patients with RCC. This study aimed to determine the relationship between TFE3 and the PI3K/Akt pathway. TFE3 down-regulation was achieved by transient transfection of siRNA and shRNA in UOK146 cells. TFE3 overexpression was induced by transient transfection with pcDNA3.1 encoding the constitutively active form of TFE3. The cells were treated with mammalian target of rapamycin (mTOR) and PI3K inhibitors. Western blot was performed to detect TFE3, programmed death-ligand 1, phospho-Akt, and Akt. Phospho-Akt expression increased significantly upon TFE3 down-regulation, and decreased significantly upon up-regulation. When RCC cells were treated with a PI3K inhibitor (LY294002), TFE3 expression increased and phospho-Akt expression decreased. Data from this study indicate that TFE3 plays a role in the PI3K/Akt pathway in RCC. The results of this study suggest that PI3K/Akt inhibitors may aid in the treatment of patients with RCC by affecting the tumor microenvironment.

Targeting mTOR and survivin concurrently potentiates radiation therapy in renal cell carcinoma by suppressing DNA damage repair and amplifying mitotic catastrophe

BACKGROUND

Renal cell carcinoma (RCC) was historically considered to be less responsive to radiation therapy (RT) compared to other cancer indications. However, advancements in precision high-dose radiation delivery through single-fraction and multi-fraction stereotactic ablative radiotherapy (SABR) have led to better outcomes and reduced treatment-related toxicities, sparking renewed interest in using RT to treat RCC. Moreover, numerous studies have revealed that certain therapeutic agents including chemotherapies can increase the sensitivity of tumors to RT, leading to a growing interest in combining these treatments. Here, we developed a rational combination of two radiosensitizers in a tumor-targeted liposomal formulation for augmenting RT in RCC. The objective of this study is to assess the efficacy of a tumor-targeted liposomal formulation combining the mTOR inhibitor everolimus (E) with the survivin inhibitor YM155 (Y) in enhancing the sensitivity of RCC tumors to radiation.

EXPERIMENTAL DESIGN

We slightly modified our previously published tumor-targeted liposomal formulation to develop a rational combination of E and Y in a single liposomal formulation (EY-L) and assessed its efficacy in RCC cell lines in vitro and in RCC tumors in vivo. We further investigated how well EY-L sensitizes RCC cell lines and tumors toward radiation and explored the underlying mechanism of radiosensitization.

RESULTS

EY-L outperformed the corresponding single drug-loaded formulations E-L and Y-L in terms of containing primary tumor growth and improving survival in an immunocompetent syngeneic mouse model of RCC. EY-L also exhibited significantly higher sensitization of RCC cells towards radiation in vitro than E-L and Y-L. Additionally, EY-L sensitized RCC tumors towards radiation therapy in xenograft and murine RCC models. EY-L mediated induction of mitotic catastrophe via downregulation of multiple cell cycle checkpoints and DNA damage repair pathways could be responsible for the augmentation of radiation therapy.

CONCLUSION

Taken together, our study demonstrated the efficacy of a strategic combination therapy in sensitizing RCC to radiation therapy via inhibition of DNA damage repair and a substantial increase in mitotic catastrophe. This combination therapy may find its use in the augmentation of radiation therapy during the treatment of RCC patients.

Targeting mTOR and Survivin Concurrently Potentiates Radiation Therapy in Renal Cell Carcinoma by Suppressing DNA Damage Repair and Amplifying Mitotic Catastrophe

Background

Renal cell carcinoma (RCC) was historically considered to be less responsive to radiation therapy (RT) compared to other cancer indications. However, advancements in precision high-dose radiation delivery through single-fraction and multi-fraction stereotactic ablative radiotherapy (SABR) have led to better outcomes and reduced treatment-related toxicities, sparking renewed interest in using RT to treat RCC. Moreover, numerous studies have revealed that certain therapeutic agents including chemotherapies can increase the sensitivity of tumors to RT, leading to a growing interest in combining these treatments. Here, we developed a rational combination of two radiosensitizers in a tumor-targeted liposomal formulation for augmenting RT in RCC. The objective of this study is to assess the efficacy of a tumor-targeted liposomal formulation combining the mTOR inhibitor everolimus (E) with the survivin inhibitor YM155 (Y) in enhancing the sensitivity of RCC tumors to radiation.

Experimental Design

We slightly modified our previously published tumor-targeted liposomal formulation to develop a rational combination of E and Y in a single liposomal formulation (EY-L) and assessed its efficacy in RCC cell lines in vitro and in RCC tumors in vivo. We further investigated how well EY-L sensitizes RCC cell lines and tumors toward radiation and explored the underlying mechanism of radiosensitization.

Results

EY-L outperformed the corresponding single drug-loaded formulations E-L and Y-L in terms of containing primary tumor growth and improving survival in an immunocompetent syngeneic mouse model of RCC. EY-L also exhibited significantly higher sensitization of RCC cells towards radiation in vitro than E-L and Y-L. Additionally, EY-L sensitized RCC tumors towards radiation therapy in xenograft and murine RCC models. EY-L mediated induction of mitotic catastrophe via downregulation of multiple cell cycle checkpoints and DNA damage repair pathways could be responsible for the augmentation of radiation therapy.

Conclusion

Taken together, our study demonstrated the efficacy of a strategic combination therapy in sensitizing RCC to radiation therapy via inhibition of DNA damage repair and a substantial increase in mitotic catastrophe. This combination therapy may find its use in the augmentation of radiation therapy during the treatment of RCC patients.

The novel CDK9 inhibitor, XPW1, alone and in combination with BRD4 inhibitor JQ1, for the treatment of clear cell renal cell carcinoma

BACKGROUND

Clear cell renal cell carcinoma (ccRCC) is a highly lethal malignancy with few therapeutic options. Cyclin‑dependent kinase 9 (CDK9), a potential therapeutic target of many cancers, has been recently observed to be upregulated in ccRCC patients. Therefore, we aimed to investigate the therapeutic potential of CDK9 in ccRCC and develop a novel CDK9 inhibitor with low toxicity for ccRCC treatment.

METHODS

The expression of CDK9 in ccRCC was checked using the online database and tissue microarray analysis. shRNA-mediated CDK9 knockdown and CDK inhibitor were applied to evaluate the effect of CDK9 on ccRCC. Medicinal chemistry methods were used to develop a new CDK9 inhibitor with drugability. RNA-seq and ChIP-seq experiments were conducted to explore the mechanism of action. MTS, western blotting, and colony formation assays were performed to evaluate the anti-ccRCC effects of CDK9 knockdown and inhibition in vitro. The in vivo anti-tumour efficacy was evaluated in a xenograft model.

RESULTS

CDK9 is overexpressed and associated with poor survival in ccRCC. Knockdown or inhibition of CDK9 significantly suppressed ccRCC cells. XPW1 was identified as a new potent and selective CDK9 inhibitor with excellent anti-ccRCC activity and low toxicity. In mechanism, XPW1 transcriptionally inhibited DNA repair programmes in ccRCC cells, resulting in an excellent anti-tumour effect. CDK9 and BRD4 were two highly correlated transcriptional regulators in ccRCC patients, and the BRD4 inhibitor JQ1 enhanced XPW1's anti-ccRCC effects in vitro and in vivo.

CONCLUSIONS

This work provides valuable insights into the therapeutic potential of CDK9 in ccRCC. The CDK9 inhibitor XPW1 would be a novel therapeutic agent for targeting ccRCC, alone or in rational combinations.

Primary and acquired resistance to first-line therapy for clear cell renal cell carcinoma

The introduction of first-line combinations had improved the outcomes for metastatic renal cell carcinoma (mRCC) compared to sunitinib. However, some patients either have inherent resistance or develop resistance as a result of the treatment. Depending on the kind of therapy employed, many factors underlie resistance to systemic therapy. Angiogenesis and the tumor immune microenvironment (TIME), nevertheless, are inextricably linked. Although angiogenesis and the manipulation of the tumor microenvironment are linked to hypoxia, which emerges as a hallmark of renal cell carcinoma (RCC) pathogenesis, it is only one of the potential elements involved in the distinctive intra- and inter-tumor heterogeneity of RCC that is still dynamic. We may be able to more correctly predict therapy response and comprehend the mechanisms underlying primary or acquired resistance by integrating tumor genetic and immunological markers. In order to provide tools for patient selection and to generate hypotheses for the development of new strategies to overcome resistance, we reviewed the most recent research on the mechanisms of primary and acquired resistance to immune checkpoint inhibitors (ICIs) and tyrosine kinase inhibitors (TKIs) that target the vascular endothelial growth factor receptor (VEGFR).We can choose patients' treatments and cancer preventive strategies using an evolutionary approach thanks to the few evolutionary trajectories that characterize ccRCC.

Prediction of Distant Metastases in Patients with Kidney Cancer Based on Gene Expression and Methylation Analysis

Clear cell renal cell carcinoma (ccRCC) is the most common and aggressive histological type of cancer in this location. Distant metastases are present in approximately 30% of patients at the time of first examination. Therefore, the ability to predict the occurrence of metastases in patients at early stages of the disease is an urgent task aimed at personalized treatment. Samples of tumor and paired histologically normal kidney tissue from patients with metastatic and non-metastatic ccRCC were studied. Gene expression was analyzed using real-time PCR. The level of gene methylation was evaluated using bisulfite conversion followed by quantitative methylation-specific PCR. Two groups of genes were analyzed in this study. The first group includes genes whose expression is significantly reduced during metastasis: CA9, NDUFA4L2, EGLN3, and BHLHE41 (p < 0.001, ROC analysis). The second group includes microRNA genes: MIR125B-1, MIR137, MIR375, MIR193A, and MIR34B/C, whose increased methylation levels are associated with the development of distant metastases (p = 0.002 to <0.001, ROC analysis). Based on the data obtained, a combined panel of genes was formed to identify patients whose tumors have a high metastatic potential. The panel can estimate the probability of metastasis with an accuracy of up to 92%.

Identification of kinases activated by multiple pro-angiogenic growth factors

Antiangiogenic therapy began as an effort to inhibit VEGF signaling, which was thought to be the sole factor driving tumor angiogenesis. It has become clear that there are more pro-angiogenic growth factors that can substitute for VEGF during tumor vascularization. This has led to the development of multi-kinase inhibitors which simultaneously target multiple growth factor receptors. These inhibitors perform better than monotherapies yet to date no multi-kinase inhibitor targets all receptors known to be involved in pro-angiogenic signaling and resistance inevitably occurs. Given the large number of pro-angiogenic growth factors identified, it may be impossible to simultaneously target all pro-angiogenic growth factor receptors. Here we search for kinase targets, some which may be intracellularly localized, that are critical in endothelial cell proliferation irrespective of the growth factor used. We develop a quantitative endothelial cell proliferation assay and combine it with "kinome regression" or KIR, a recently developed method capable of identifying kinases that influence a quantitative phenotype. We report the kinases implicated by KIR and provide orthogonal evidence of their importance in endothelial cell proliferation. Our approach may point to a new strategy to develop a more complete anti-angiogenic blockade.

Immune-Associated Gene Signatures Serve as a Promising Biomarker of Immunotherapeutic Prognosis for Renal Clear Cell Carcinoma

As the most common type of renal cell carcinoma (RCC), the renal clear cell carcinoma (ccRCC) is highly malignant and insensitive to chemotherapy or radiotherapy. Although systemic immunotherapies have been successfully applied to ccRCC in recent years, screening for patients who can benefit most from these therapies is still essential and challenging due to immunological heterogeneity of ccRCC patients. To this end, we implemented a series of deep investigation on the expression and clinic data of ccRCC from The Cancer Genome Atlas (TCGA) International Consortium for Cancer Genomics (ICGC). We identified a total of 946 immune-related genes that were differentially expressed. Among them, five independent genes, including SHC1, WNT5A, NRP1, TGFA, and IL4R, were significantly associated with survival and used to construct the immune-related prognostic differential gene signature (IRPDGs). Then the ccRCC patients were categorized into high-risk and low-risk subgroups based on the median risk score of the IRPDGs. IRPDGs subgroups displays distinct genomic and immunological characteristics. Known immunotherapy-related genes show different mutation burden, wherein the mutation rate of VHL was higher than 40% in the two IRPDGs subgroups, and SETD2 and BAP1 mutations differed most between two groups with higher frequency in the high-risk subgroup. Moreover, IRPDGs subgroups had different abundance in tumor-infiltrating immune cells (TIICs) with distinct immunotherapy efficacy. Plasma cells, regulatory cells (Tregs), follicular helper T cells (Tfh), and M0 macrophages were enriched in the high-risk group with a higher tumor immune dysfunction and rejection (TIDE) score. In contrast, the low-risk group had abundant M1 macrophages, mast cell resting and dendritic cell resting infiltrates with lower TIDE score and benefited more from immune checkpoint inhibitors (ICI) treatment. Compared with other biomarkers, such as TIDE and tumor inflammatory signatures (TIS), IRPDGs demonstrated to be a better biomarker for assessing the prognosis of ccRCC and the efficacy of ICI treatment with the promise in screening precise patients for specific immunotherapies.

68Ga-PSMA-11 PET/CT Parameter Correlates with Pathological VEGFR-2/PDGFR-β Expression in Renal Cell Carcinoma Patients

BACKGROUND

Response prediction is necessary for renal cell carcinoma (RCC) tumors. We aim to evaluate parameters derived from ⁶⁸ Ga-PSMA-11 PET/CT images for prediction of pathological VEGFR-2/PDGFR-β expression of primary RCC tumors.

METHODS

Forty-eight RCC patients were retrospectively enrolled with preoperative ⁶⁸ Ga-PSMA-11 PET/CT scan and surgical specimen. Radiological parameters including tumor diameter, mean CT value, and maximal standard uptake value (SUV_max) were derived from PET/CT images and pathological VEGFR-2/PDGFR-β/PSMA expression were identified with immunohistochemistry. Mann-Whitney U test was performed for continuous variables and the chi-square test for categorical variables. ROC was used for determining the effectiveness of preoperative parameters in differentiating VEGFR-2/PDGFR-β expression. Univariate and multivariate logistic regression analyses were performed for significant parameters to predict VEGFR-2 & PDGFR-β co-expression.

RESULTS

Of the 48 tumors, 25 (52.1%) harbored positive VEGFR-2 expression, 28 (58.3%) harbored positive PDGFR-β expression, and 24 (50%) were both VEGFR-2 positive and PDGFR-β positive. SUV_max significantly differed by subgroups of VEGFR-2/PDGFR-β expression (both P < 0.001). SUV_max demonstrated superior performance for differentiating VEGFR-2 & PDGFR-β co-expression (positive vs. negative), with area under the curve 0.87 (95% CI 0.78-0.96, P < 0.001), sensitivity 93% and specificity 78%. Moreover, SUV_max was identified as the significant predictor for VEGFR-2 & PDGFR-β co-expression (odds ratio 4.01, 95% CI 1.99-8.08, P < 0.001). Concordant with radiological findings with ⁶⁸ Ga-PSMA-11 PET/CT, pathological PSMA staining intensity was significantly higher in both VEGFR-2-positive tumor and PDGFR-β-positive tumor (P = 0.009 and P < 0.001, respectively).

CONCLUSION

⁶⁸ Ga-PSMA-11 PET/CT could effectively identify pathological VEGFR-2/PDGFR-β expression of primary RCC tumors, which may help with selection of mRCC patients suitable for TKIs treatment.

Matrix metalloproteinase 12 is an independent prognostic factor predicting postoperative relapse of conventional renal cell carcinoma - a short report

Purpose

Approximately 15% of clinically localised conventional renal cell carcinomas (cRCC) develop metastases within 5 years of follow-up. Sarcomatous cRCC is a highly malignant cancer of the kidney. The aim of our study was to identify biomarkers for estimating the postoperative progression of cRCCs.

Methods

Global microarray-based gene expression analysis of RCCs with and without sarcomatous changes revealed that a high MMP12 expression was associated with a sarcomatous histology. Additionally, we analysed MMP12 expression using a multi-tissue array comprising 736 cRCC patients without metastasis at the time of surgery. The median follow-up time was 66 ± 29 months.

Results

Immunohistochemistry revealed MMP12 expression in 187 of 736 cRCCs with good follow-up data. Subsequent Kaplan–Meier analysis revealed that patients with MMP12 positive tumours exhibited a significantly shorter tumour-free survival (p < 0.001). In multivariate Cox regression analysis a weak to strong MMP12 expression indicated a 2.4–2.8 times higher risk of postoperative tumour relapse (p < 0.001; p < 0.003, respectively).

Conclusions

MMP12 may serve as a biomarker to estimate postoperative cRCC relapse and as a possible target for penfluridol therapy.

Updates on Immunotherapy and Immune Landscape in Renal Clear Cell Carcinoma

Several clinicopathological features of clear cell renal cell carcinomas (ccRCC) contribute to make an "atypical" cancer, including resistance to chemotherapy, sensitivity to anti-angiogenesis therapy and ICIs despite a low mutational burden, and CD8+ T cell infiltration being the predictor for poor prognosis-normally CD8+ T cell infiltration is a good prognostic factor in cancer patients. These "atypical" features have brought researchers to investigate the molecular and immunological mechanisms that lead to the increased T cell infiltrates despite relatively low molecular burdens, as well as to decipher the immune landscape that leads to better response to ICIs. In the present study, we summarize the past and ongoing pivotal clinical trials of immunotherapies for ccRCC, emphasizing the potential molecular and cellular mechanisms that lead to the success or failure of ICI therapy. Single-cell analysis of ccRCC has provided a more thorough and detailed understanding of the tumor immune microenvironment and has facilitated the discovery of molecular biomarkers from the tumor-infiltrating immune cells. We herein will focus on the discussion of some major immune cells, including T cells and tumor-associated macrophages (TAM) in ccRCC. We will further provide some perspectives of using molecular and cellular biomarkers derived from these immune cell types to potentially improve the response rate to ICIs in ccRCC patients.

Identification of immunization-related new prognostic biomarkers for papillary renal cell carcinoma by integrated bioinformatics analysis

Background

Despite papillary renal cell carcinoma (pRCC) being the second most common type of kidney cancer, the underlying molecular mechanism remains unclear. Targeted therapies in the past have not been successful because of the lack of a clear understanding of the molecular mechanism. Hence, exploring the underlying mechanisms and seeking novel biomarkers for pursuing a precise prognostic biomarker and appropriate therapies are critical.

Material and methods

In our research, the differentially expressed genes (DEGs) were screened from the TCGA and GEO databases, and a total of 149 upregulated and 285 downregulated genes were sorted. This was followed by construction of functional enrichment and protein–protein interaction (PPI) network, and then the top 15 DEGs were selected for further analysis. The P4HB gene was chosen as our target gene by repetitively validating multiple datasets, and higher levels of P4HB expression predicted lower overall survival (OS) in patients with pRCC.

Results

We found that P4HB not only connects with immune cell infiltration and co-expression with PD-1, PD-L2, and CTLA-4, but also has a strong connection with the newly discovered hot gene, TOX.

Conclusion

We speculate that P4HB is a novel gene involved in the progression of pRCC through immunomodulation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-021-01092-w.

circAMOTL1L Suppresses Renal Cell Carcinoma Growth by Modulating the miR-92a-2-5p/KLLN Pathway

Accumulating evidence indicates that the dysregulation of circular RNAs (circRNAs) contributes to tumor progression; however, the regulatory functions of circRNAs in renal cell carcinoma (RCC) remain largely unknown. In this study, the function and underlying mechanism of circAMOTL1L in RCC progression were explored. qRT-PCR showed the downregulation of circAMOTL1L in RCC tissues and cell lines. The decrease in circAMOTL1L expression correlated with the tumor stage, metastasis, and poor prognosis in patients with RCC. Functional experiments revealed that circAMOTL1L inhibited cell proliferation and increased apoptosis in RCC cells. Subcutaneous implantation with circAMOTL1L-overexpressing cells in nude mice decreased the growth ability of the xenograft tumors. Mechanistically, circAMOTL1L served as a sponge for miR-92a-2-5p in upregulating KLLN (killin, p53-regulated DNA replication inhibitor) expression validated by bioinformatics analysis, oligo pull-down, and luciferase assays. Further, reinforcing the circAMOTL1L-miR-92a-2-5p-KLLN axis greatly reduced the growth of RCC in vivo. Conclusively, our findings demonstrate that circAMOTL1L has an antioncogenic role in RCC growth by modulating the miR-92a-2-5p-KLLN pathway. Thus, targeting the novel circAMOTL1L-miR-92a-2-5p-KLLN regulatory axis might provide a therapeutic strategy for RCC.

Outcomes of axitinib versus sunitinib as first-line therapy to patients with metastatic renal cell carcinoma in the immune-oncology era

Although combination immune checkpoint inhibitor (immuno‐oncology [IO]) therapy is the first‐line treatment for metastatic renal cell carcinoma (mRCC), it mostly causes resistance and tumor regrowth. Therefore, an optimal second‐line therapy is necessary. Such therapy typically comprises vascular endothelial growth factor receptor‐tyrosine kinase inhibitors (VEGFR‐TKIs). This study was aimed at comparing the efficacy of two TKIs—axitinib and sunitinib—in mRCC patients. From January 2008 to October 2018, we registered 703 mRCC patients from 8 Japanese institutes. Of these, 408 patients received axitinib or sunitinib as the first‐line treatment. Thereafter, efficacy and survival rate were compared between the axitinib and sunitinib groups. To reduce the effects of selection bias and potential confounders, propensity score matching analysis was performed. Axitinib and sunitinib were administered in 274 and 134 patients, respectively. More than 25% of the patients received nivolumab sequence therapy. To calculate the propensity scores for each patient, we performed multivariate logistic regression analysis. The objective response rate, progression‐free survival (PFS), cause‐specific survival, and overall survival (OS) were significantly better in the axitinib group than in the sunitinib group. Furthermore, the OS was better in the nivolumab‐treated patients in the axitinib group. Axitinib showed higher efficacy and afforded greater survival benefits than did sunitinib when administered as first‐line therapy in mRCC patients. Thus, from among VEGFR‐TKIs, axitinib might be a possible option for application in the middle of IO drug‐based treatment sequences.

The Molecular Characteristics of Non-Clear Cell Renal Cell Carcinoma: What's the Story Morning Glory?

Non-clear cell renal cell carcinomas are a miscellaneous group of tumors that include different histological subtypes, each one characterized by peculiarity in terms of genetic alteration, clinical behavior, prognosis, and treatment response. Because of their low incidence and poor enrollment in clinical trials, alongside their heterogeneity, additional efforts are required to better unveil the pathogenetic mechanisms and, consequently, to improve the treatment algorithm. Nowadays, tyrosine kinase inhibitors, mTOR and MET inhibitors, and even cisplatin-based chemotherapy and immunotherapy are potential weapons that are still under evaluation in this setting. Various biomarkers have been evaluated for detecting progression and monitoring renal cell carcinoma, but more studies are necessary to improve this field. In this review, we provide an overview on the molecular characteristics of this group of tumors and the recently published trials, giving an insight into what might become the future therapeutic standard in this complex world of non-clear cell kidney cancers.

Determinants of resistance to VEGF-TKI and immune checkpoint inhibitors in metastatic renal cell carcinoma

Vascular endothelial growth factor tyrosine kinase inhibitors (VEGF-TKIs) have been the mainstay of treatment for patients with advanced renal cell carcinoma (RCC). Despite its early promising results in decreasing or delaying the progression of RCC in patients, VEGF-TKIs have provided modest benefits in terms of disease-free progression, as 70% of the patients who initially respond to the treatment later develop drug resistance, with 30% of the patients innately resistant to VEGF-TKIs. In the past decade, several molecular and genetic mechanisms of VEGF-TKI resistance have been reported. One of the mechanisms of VEGF-TKIs is inhibition of the classical angiogenesis pathway. However, recent studies have shown the restoration of an alternative angiogenesis pathway in modulating resistance. Further, in the last 5 years, immune checkpoint inhibitors (ICIs) have revolutionized RCC treatment. Although some patients exhibit potent responses, a non-negligible number of patients are innately resistant or develop resistance within a few months to ICI therapy. Hence, an understanding of the mechanisms of VEGF-TKI and ICI resistance will help in formulating useful knowledge about developing effective treatment strategies for patients with advanced RCC. In this article, we review recent findings on the emerging understanding of RCC pathology, VEGF-TKI and ICI resistance mechanisms, and potential avenues to overcome these resistance mechanisms through rationally designed combination therapies.

Differential sensitivity of renal carcinoma cells to doxorubicin and epigenetic therapeutics depends on the genetic background

Differential sensitivity to chemotherapeutics is a limitation in chemotherapy of kidney cancer patients. Role of genetic background in chemotherapy is not fully understood. Therefore, this study evaluated the influence of genetic/epigenetic background of renal cancer cells on the sensitivity to chemotherapeutics. Two renal cell carcinoma (RCC) cell lines, Caki-1 and 786-0, with different genetic makeup of p53 and VHL were treated with doxorubicin either alone or in combination with epigenetic therapeutics 5-aza-2-dc and TSA. Sensitivity of RCC cells to these drugs was evaluated by cell viability and cell cycle analysis and was further confirmed by analysis of selected genes expression. Cell viability data revealed that 786-0 cells were more sensitive than Caki-1 to doxorubicin. Combination of doxorubicin with 5-aza-2-dc or TSA was more effective to inhibit growth of Caki-1 cells but not the 786-0. Data of cell cycle analysis and expression of representative genes for tumor suppressor, cell cycle and survival, drug transporter and DNA repair further provided the molecular basis for differential sensitivity of Caki-1 and 786-0 cell lines to doxorubicin. Important findings of this study suggest that doxorubicin is more cytotoxic to primary renal cancer 786-0 cells with mutant VHL and p53 than the metastatic Caki-1 cells with wild-type VHL and p53, and this differential response was independent of p53 expression level. This study suggests that combination of doxorubicin with epigenetic therapeutics could potentially be beneficial in clinical treatment of renal cancer patients with wild-type VHL and p53 but not in patients with mutant VHL and p53.

Soluble PD-L1 Is an Independent Prognostic Factor in Clear Cell Renal Cell Carcinoma

Simple Summary

Renal cell carcinoma (RCC) is a heterogeneous and complex disease with almost no response to chemotherapy. Immune checkpoint inhibitors have achieved great clinical success but no interesting circulating markers of clinical use have developed so far in clear cell renal cell carcinoma (CCRCC). We investigate the diagnostic and prognostic role of plasma PD-1 (sPD-1) and PD-L1 (sPD-L1) proteins for the first time together with the immunohistochemical expression counterpart of these proteins within the tumor front and tumor center in the same sample of patients with renal cancer undergoing surgery. We also investigate these plasma and tissue markers in the population of metastatic patients according to International mRCC Database Consortium (IMDC) prognostic groups and the response to systemic therapy. The independent role of sPD-L1 as a predictor of prognosis and treatment response is demonstrated.

Abstract

(1). Background: Immunohistochemical (IHC) evaluation of programmed death-1 (PD-1) and its ligand (PD-L1) is being used to evaluate advanced malignancies with potential response to immune checkpoint inhibitors. We evaluated both plasma and tissue expression of PD-1 and PD-L1 in the same cohort of patients, including non-metastatic and metastatic clear cell renal cell carcinoma (CCRCC). Concomitant plasma and tissue expression of PD-1 and PD-L1 was evaluated with emphasis on diagnostic and prognostic implications. (2) Methods: we analyzed PD-1 and PD-L1 IHC expression in tumor tissues and soluble forms (sPD-1 and sPD-L1) in plasma from 89 patients with CCRCC, of which 23 were metastatic and 16 received systemic therapy. The primary endpoint was evaluation of overall survival using Kaplan-Meier analysis and the Cox regression model. Plasma samples from healthy volunteers were also evaluated. (3) Results: Interestingly, sPD-1 and sPD-L1 levels were lower in cancer patients than in controls. sPD-1 and sPD-L1 levels and their counterpart tissue expression both at the tumor center and infiltrating front were not associated. Higher expression of both PD-1 and PD-L1 were associated with tumor grade, necrosis and tumor size. PD-1 was associated to tumor stage (pT) and PD-L1 to metastases. sPD-1 and sPD-L1 were not associated with clinico-pathological parameters, although both were higher in patients with synchronous metastases compared to metachronous ones and sPD-L1 was also higher for metastatic patients compared to non-metastatic patients. sPD-1 was also associated with the International Metastatic Renal Cell Cancer Database Consortium (IMDC) prognostic groups in metastatic CCRCC and also to the Morphology, Attenuation, Size and Structure (MASS) response criteria in metastatic patients treated with systemic therapy, mainly tyrosine-kinase inhibitors. Regarding prognosis, PD-L1 immunostaining at the tumor center with and without the tumor front was associated with worse survival, and so was sPD-L1 at a cut-off >793 ng/mL. Combination of positivity at both the tissue and plasma level increased the level of significance to predict prognosis. (4) Conclusions: Our findings corroborate the role of PD-L1 IHC to evaluate prognosis in CCRCC and present novel data on the usefulness of plasma sPD-L1 as a promising biomarker of survival in this neoplasia.

Epigenetic Alterations in Renal Cell Cancer With TKIs Resistance: From Mechanisms to Clinical Applications

The appearance of tyrosine kinase inhibitors (TKIs) has been a major breakthrough in renal cell carcinoma (RCC) therapy. Unfortunately, a portion of patients with TKIs resistance experience disease progression after TKIs therapy. Epigenetic alterations play an important role in the development of TKIs resistance. Current evidence suggests that epigenetic alterations occur frequently in RCC patients with poor response to TKIs therapy, and modulation of them could enhance the cytotoxic effect of antitumor therapy. In this review, we summarize the currently known epigenetic alterations relating to TKIs resistance in RCC, focusing on DNA methylation, non-coding RNAs (ncRNAs), histone modifications, and their interactions with TKIs treatment. In addition, we discuss application of epigenetic alteration analyses in the clinical setting to predict prognosis of patients with TKIs treatment, and the potential use of epigenetics-based therapies to surmount TKIs resistance.

The clinical significance of routine risk categorization in metastatic renal cell carcinoma and its impact on treatment decision-making: a systematic review

Aim: To analyze responses to first-line metastatic renal cell carcinoma (mRCC) treatment stratified by risk criteria. Patients & methods: Clinical trials and observational studies of patients aged ≥18 years, published January 2005-May 2019, were identified via Ovid from MEDLINE, EMBASE, the Cochrane Central Trials Register and the Cochrane Database of Systematic Reviews. Data extracted included progression-free survival (PFS), overall survival (OS) and objective response rate (ORR). Results: 47/1269 articles met eligibility criteria. Most studies stratified patients by International Metastatic RCC Database Consortium (n = 19) or Memorial Sloan Kettering Cancer Center (n = 21). PFS, OS and ORR varied according to risk group. Conclusion: Pembrolizumab + axitinib, ipilimumab + nivolumab and avelumab + axitinib were most effective across all risk groups. Favorable-risk patients benefit from sunitinib treatment.

Designing novel immunocombinations in metastatic renal cell carcinoma

Immune checkpoint inhibitors have radically changed the treatment approach to metastatic renal cell carcinoma (mRCC). In the present article, we reported and discussed the available data with immunocombinations in mRCC, offering new perspectives in the treatment landscape of these patients. We discussed the main results of pivotal clinical trials of immune checkpoint inhibitors in the treatment of mRCC. Moreover, we discussed novel immuno-based treatments currently under investigation in ongoing clinical trials. Renal cell carcinoma is a particularly immunogenic tumor and immunotherapy is a pivotal treatment approach. A wide series of clinical trials is exploring novel promising immunocombinations in patients with renal cell carcinoma.

Significance of tumor microenvironment in acquiring resistance to vascular endothelial growth factor-tyrosine kinase inhibitor and recent advance of systemic treatment of clear cell renal cell carcinoma

The development of systemic therapies, including vascular endothelial growth factor-tyrosine kinase inhibitors (VEGF-TKI) and mammalian target of rapamycin (mTOR) inhibitors, represents a major breakthrough in the treatment of patients with renal cell carcinoma (RCC). However, inherent resistance is observed in some patients and acquired resistance commonly develops in many patients within several months of the initiation of systemic therapies. Since these treatments rarely cure patients, their aim is to suppress tumor progression and prolong survival. Therefore, the establishment of dependable criteria that predict responses and resistance to systemic therapies is clinically important, and the underlying molecular mechanisms also need to be elucidated for the future development of more effective therapies. We herein review recent advances in research on the molecular mechanisms underlying resistance, with a focus on morphological characteristics, tumor angiogenesis, and the tumor immune microenvironment in RCC and their relationships with VEGF-TKI treatments. Recent therapies using immune checkpoint inhibitors (ICI) and newly developed VEGF-TKI also appear to be effective for advanced RCC, with stable and durable responses to ICI being observed in some RCC patients. These new drugs and their outcomes have been briefly described.

Avelumab and axitinib in the treatment of renal cell carcinoma: safety and efficacy

Introduction: The incidence of advanced renal cell carcinoma (RCC) is increasing. Over the last 10 years targeted therapies have led to improved efficacy outcomes for renal carcinoma, including longer survival. However, the majority of patients develop disease progression within a year of initiation of first-line therapy. Recently a number of new regimens have been investigated including the combination of immune checkpoint inhibitors with VEGF inhibitors.Areas covered: In this review, we assess the efficacy and safety of avelumab/axitinib in treatment-naïve patients with metastatic RCC and compare this combination to other current and emerging treatment regimens. In the Javelin 101 phase III registration trial, avelumab/axitinib demonstrated superior response rates and progression-free survival compared to sunitinib. However, after follow-up of 11.6 months, there was no significant difference in overall survival (OS). Avelumab/axitinib showed a tolerable safety profile. Adverse events were manageable and were in line with expected toxicities from the single agents.Expert Opinion: Avelumab/axitinib has shown impressive efficacy and a tolerable safety profile in metastatic RCC. The future role of this treatment combination in the rapidly evolving landscape of novel combinations in this disease will have to be defined.

Esculetin inhibits proliferation, migration, and invasion of clear cell renal cell carcinoma cells

BACKGROUND

Esculetin, the main active ingredient in the Chinese herbal medicineCortex Fraxini, has been shown to possess antitumor activity. However, the effect of esculetin on clear cell renal cell carcinoma (ccRCC) has not been investigated.

METHODS

MTS assays and colony formation assays were used to study the cytotoxicity of esculetin. The effects of esculetin on cell cycle and apoptosis were analyzed by flow cytometry. Western blot was used to detect cell cycle-, apoptosis-, and EMT-related proteins. Wound-healing assays and transwell assays were performed to study the effect of esculetin on cell migration and invasion in the ccRCC cell lines 786-O and SN12-PM6.

RESULTS

Esculetin exerted cytotoxic activities in 786-O and SN12-PM6 cells in a dose- and time-dependent manner. The compound arrested the cell cycle in G0/G1 and G2/M phase with down-regulation of Cyclin D1, CDK4, CDK6, and c-Myc expression. Esculetin also induced apoptosis and the expression of cleaved caspase 3 increased. Additionally, esculetin significantly inhibited 786-O and SN12-PM6 cell migration and invasion, the expression of E-Cadherin increased, and the expression of N-cadherin and vimentin decreased.

CONCLUSION

Taken together, these results suggest that esculetin inhibits proliferation, migration, and invasion of ccRCC and is a potential novel therapeutic agent for the treatment of ccRCC.

DUSP9 Suppresses Proliferation and Migration of Clear Cell Renal Cell Carcinoma via the mTOR Pathway

BACKGROUND

Clear cell renal cell carcinoma (ccRCC) is one of the most common urologic tumors. However, the carcinogenic mechanism of ccRCC remains unclear. This study aimed to investigate the effects of dual specificity phosphatase 9 (DUSP9) in ccRCC.

METHODS

Cell proliferation and migration abilities were detected by Cell Counting kit-8, wound-healing (scratch) assay and transwell assay. The expression of mRNA in ccRCC was measured by qPCR. Western blot and immunohistochemical staining were used for protein expression. In addition, nude mouse xenograft experiment establishes an in vivo model to detect the inhibitory effect of DUSP9 on tumor proliferation.

RESULTS

DUSP9 was significantly down-regulated in both ccRCC cell lines and ccRCC tissues compared to that in non-cancer cell lines and normal tissues. Besides, DUSP9 suppressed proliferation and migration of ccRCC cell lines in vitro. Importantly, the inhibition of tumor growth by DUSP9 was confirmed by xenograft tumor studies. And DUSP9 could inhibit both phosphorylation of mTOR and expression of its pathway-associated proteins Sox2, c-Myc, and HIF-1α, which are involved in cell proliferation and migration.

CONCLUSION

Taken together, our results uncovered DUSP9 as a tumor suppressor in ccRCC, acting by regulating cell proliferation and migration via the mTOR pathway.

The Genes-Candidates for Prognostic Markers of Metastasis by Expression Level in Clear Cell Renal Cell Cancer

The molecular prognostic markers of metastasis are important for personalized approaches to clear cell renal cell carcinoma (ccRCC) treatment but markers for practical use are still missing. To address this gap we studied the expression of ten genes—CA9, NDUFA4L2, VWF, IGFBP3, BHLHE41, EGLN3, SAA1, CSF1R, C1QA, and FN1—through RT-PCR, in 56 ccRCC patients without metastases and with metastases. All of these, excluding CSF1R, showed differential and increased (besides SAA1) expression in non-metastasis tumors. The gene expression levels in metastasis tumors were decreased, besides CSF1R, FN1 (not changed), and SAA1 (increased). There were significant associations of the differentially expressed genes with ccRCC metastasis by ROC analysis and the Fisher exact test. The association of the NDUFA4L2, VWF, EGLN3, SAA1, and C1QA expression with ccRCC metastasis is shown for the first time. The CA9, NDUFA4L2, BHLHE4, and EGLN3 were distinguished as the strongest candidates for ccRCC metastasis biomarkers. We used an approach that presupposed that the metastasis marker was the expression levels of any three genes from the selected panel and received sensitivity (88%) and specificity (73%) levels with a relative risk of RR > 3. In conclusion, a panel of selected genes—the candidates in biomarkers of ccRCC metastasis—was created for the first time. The results might shed some light on the ccRCC metastasis processes.

Immunotherapy in renal cell carcinoma from poverty to the spoiled of choice

Management of metastatic renal cell carcinoma has been enriched by the advent of new therapeutic compounds. The approval of new combination strategies between targeted agents and immune-checkpoint inhibitors as well as the administration of combinations between immune-checkpoint inhibitors has clearly demonstrated significant improvement toward patients' prognosis and other clinical outcomes. Due to the availability of different treatments, the choice between them may be a difficult issue in our clinical practice. We have summarized current knowledge about available treatments focusing on criteria, which may help clinicians to make decisions.

Toward a genome-based treatment landscape for renal cell carcinoma

Knowledge about molecular mechanisms driving development and progression of renal cell carcinoma has been elucidated by different studies. In few years we discovered a large difference between genomic landscapes of clear cell and non-clear cell carcinoma. Moreover, tumor heterogeneity and different acquisition of gene mutations during tumor progression are issues of particular interest. In this review we focalized our attention on principal genomic alterations identified among RCC subtypes. Acquired gene mutations may be an adaptive response to several external pressure including metabolic, treatment, genomic and immune-related external pressure. Thus we correlated and discussed principal genomic alterations adopted by tumor to escape from each external pressures. The aim of the present work is to summarize current knowledge about genomic alterations in RCC with special interest of treatment strategies tailored on the basis of disease mutations assessment.