Apelin and apelin receptor expression in renal cell carcinoma.

BACKGROUND: The APLNR (apelin receptor) has been shown to be an essential gene for cancer immunotherapy, with deficiency in APLNR leading to immunotherapy failure. The aim of this study is to investigate the expression of APLN (apelin) and APLNR in patients with renal cell carcinoma (RCC), and its association with clinicopathological parameters and survival. METHODS: Three well-characterised patient cohorts with RCC were used: Study cohort 1 (clear-cell RCC; APLN/APLNR mRNA expression; n = 166); TCGA validation cohort (clear-cell RCC; APLN/APLNR mRNA expression; n = 481); Study cohort 2 (all RCC subtypes; APLNR protein expression/immunohistochemistry; n = 300). Associations between mRNA/protein expression and clinicopathological variables/patients' survival were tested statistically. RESULTS: While APLN showed only very weak association with tumour histological grade (TCGA cohort), APLNR/mRNA protein expression correlate significantly with ccRCC aggressiveness. APLNR is expressed in tumour vasculature and tumour cells at different levels, and these expression levels associate with tumour aggressiveness in opposing directions. APLNR expression was negatively correlated with PD-L1 expression by tumour cells in a subset of patients with ccRCC. APLNR expression in either compartment is an independent prognostic factor for survival of patients with ccRCC. CONCLUSION: The APLNR/APLN-system appears to play an important role in ccRCC, warranting further clinical investigation.

Increased Efficacy of Brentuximab Vedotin (SGN-35) in Combination with Cytokine-Induced Killer Cells in Lymphoma.

Brentuximab vedotin (SGN-35) is an antibody-drug conjugate with a high selectivity against CD30⁺ cell lines and more than 300-fold less activity against antigen-negative cells. In the last years, the results of many in vitro and in vivo studies have led to the fast approval of this drug to treat lymphoma patients. Another innovative method to treat tumor cells including lymphoma cells is the use cytokine-induced killer (CIK) cells, which have also been approved and proven to be a safe treatment with only minor adverse events. In this study, a possible additive effect when combining SGN-35 with CIK cells was investigated. The combinational treatment showed that it reduces the viability of CD30⁺ cell lines significantly in vitro. Additionally, the amount of lymphoma cells was significantly reduced when exposed to CIK cells as well as when exposed to SGN-35. A significant negative effect of SGN-35 on the function of CIK cells could be excluded. These results lead to the assumption that SGN-35 and CIK cells in combination might achieve better results in an in vitro setting compared to the single use of SGN-35 and CIK cells. Further investigations in in vivo models must be conducted to obtain a better understanding of the exact mechanisms of both treatments when applied in combination.

RNA Sequencing Reveals Alterations and Similarities in Cell Metabolism, Hypoxia and Immune Evasion in Primary Cell Cultures of Clear Cell Renal Cell Carcinoma.

The treatment of advanced renal cell carcinoma remains a challenge. To develop novel therapeutic approaches, primary cell cultures as an in vitro model are considered more representative than commercial cell lines. In this study, we analyzed the gene expression of previously established primary cell cultures of clear cell renal cell carcinoma by bulk (3'm)RNA sequencing and compared it to the tissue of origin. The objectives were the identification of dysregulated pathways under cell culture conditions. Furthermore, we assessed the suitability of primary cell cultures for studying crucial biological pathways, including hypoxia, growth receptor signaling and immune evasion. RNA sequencing of primary cell cultures of renal cell carcinoma and a following Enrichr database analysis revealed multiple dysregulated pathways under cell culture conditions. 444 genes were significantly upregulated and 888 genes downregulated compared to the tissue of origin. The upregulated genes are crucial in DNA repair, cell cycle, hypoxia and metabolic shift towards aerobic glycolysis. A downregulation was observed for genes involved in pathways of immune cell differentiation and cell adhesion. We furthermore observed that 7275 genes have a similar mRNA expression in cell cultures and in tumor tissue, including genes involved in the immune checkpoint signaling or in pathways responsible for tyrosine kinase receptor resistance. Our findings confirm that primary cell cultures are a representative tool for specified experimental approaches. The results presented in this study give further valuable insights into the complex adaptation of patient-derived cells to a new microenvironment, hypoxia and other cell culture conditions, which are often neglected in daily research, and allow new translational and therapeutic approaches.

Overexpression of Parkin in clear cell renal cell carcinoma decreases tumor aggressiveness by regulating CKS2 levels.

Low expression levels of the E3 ubiquitin­protein ligase Parkin (PARK2) are exhibited in several cancer entities, including clear cell renal cell carcinoma (ccRCC), and are associated with poor prognosis; however, PARK2 can also function as a tumor suppressor gene. The aim of the present study was to thoroughly investigate the effects of PARK2 overexpression in ccRCC cell lines and to determine its effects on malignancy by conducting functional assays such as cell cycle analysis, apoptosis analysis, migration and invasion assays. Furthermore, liquid chromatography­mass spectrometry was used to decipher potential targets of PARK2 that may influence the behavior of ccRCC tumor cells. In addition, ccRCC tumor tissues from a patient cohort were examined in tissue microarrays to find correlations between different clinical parameters. In the present study, it was demonstrated that the induction of PARK2 resulted in a less aggressive phenotype, as indicated by lower migration and invasion in ccRCC cell lines. Mass spectrometry revealed decreased levels of 29 proteins in cells with PARK2 overexpression, including CDC28 protein kinase regulatory subunit 2 (CKS2), which is highly expressed in numerous types of cancer. The link between the function of PARK2 as an E3 ubiquitin ligase and the low expression levels of CKS2 was investigated by mutating the catalytic domain of the PARK2 gene, and it was found that the effect of decreased migration was abolished in 786­O and RCC­MH ccRCC cell lines. CKS2 silencing decreased migratory ability of the cells. Furthermore, it was revealed that high CKS2 levels are associated with high tumor grading in patient samples and lower patient survival. In conclusion, the results from the present study indicated that PARK2 may signal via CKS2 to affect tumor behavior. In consequence, CKS2 may be a biomarker in ccRCC and may also serve as potential target for ccRCC therapy.

Tumor Infiltrating Neutrophils Are Frequently Found in Adenocarcinomas of the Biliary Tract and Their Precursor Lesions with Possible Impact on Prognosis.

Biliary tract cancer (BTC) is characterized by an intense stromal reaction and a complex landscape of infiltrating immune cells. Evidence is emerging that tumor-infiltrating neutrophils (TINs) have an impact on carcinogenesis and tumor progression. TINs have also been associated with outcomes in various solid malignant tumors but their possible clinical role in BTC is largely unknown. Tissue samples from patients with sporadic BTC ("spBTC" cohort, N = 53) and BTC in association with primary sclerosing cholangitis ("PSC-BTC" cohort, N = 7) were collected. Furthermore, tissue samples from 27 patients with PSC who underwent liver transplantation ("PSC-LTX" cohort) were investigated. All specimens were assessed for TIN density in invasive and precancerous lesions (biliary intraepithelial neoplasia, BilIN). Most spBTC showed low TIN density (LD, 61%). High TIN density (HD) was detected in 16% of the tumors, whereas 23% were classified as intermediate density (ID); the majority of both HD and ID groups were in T1-T2 tumors (83% and 100%, p = 0.012). TIN density in BilIN lesions did not significantly differ among the three groups. The HD group had a mean overall survival (OS) of 53.5 months, whereas the mean OS in the LD and ID groups was significantly shorter (LD 29.5 months vs. ID 24.6 months, log-rank p < 0.05). The results of this study underline the possible prognostic relevance of TINs in BTC and stress the complexity of the immune cell landscape in BTC. The prognostic relevance of TINs suggests a key regulator role in inflammation and immune landscape in BTC.

A Combined TLR7/TLR9/GATA3 Score Can Predict Prognosis in Biliary Tract Cancer.

Biliary tract cancer (BTC) refers to a heterogenous group of epithelial malignancies arising along the biliary tree. The highly aggressive nature combined with its silent presentation contribute to the dismal prognosis of this tumor. Tumor-infiltrating immune cells (TIICs) are frequently present in BTC and there is growing evidence regarding their role as therapeutic targets. In this study, we analyzed the immune cell infiltration in BTC and developed a promising immune signature score to predict prognosis in BTC. Immunohistochemistry (IHC) was carried out on tissue microarray sections from 45 patients with resectable cholangiocarcinoma for the detection of 6-sulfoLacNAc+ monocytes (slanMo), BDCA-2+ plasmacytoid dendritic cells (pDC), CD8+ or CD4+T-lymphocytes, CD103+ cells, GATA3+ cells, Toll-like receptor (TLR) 3, 7 and 9-expressing cells as well as programmed cell death protein 1 and programmed cell death ligand 1 positive cells. Data from the IHC staining were analyzed and correlated with clinicopathological and survival data. High expression of TLR7, TLR9, and GATA3 was associated with improved overall survival (OS, Log-rank p < 0.05). In addition, TLR9 was associated with better disease-free survival (Log-rank p < 0.05). In the multivariate Cox proportional-hazards model for OS, the TLR/TLR9/GATA3 score was found to be an independent prognostic factor for OS ("Score 2" vs. "Score 0": HR 11.17 95% CI 2.27-54.95, p < 0.01).

Cultivation of Clear Cell Renal Cell Carcinoma Patient-Derived Organoids in an Air-Liquid Interface System as a Tool for Studying Individualized Therapy.

Clear cell renal cell carcinoma (ccRCC) is the most common renal cancer accounting for 80% of all renal cancers as well as the majority of renal cancer-associated deaths. During the last decade, the treatment paradigm for ccRCC has radically changed. In particular, the recent development of immune checkpoint inhibitors (ICI) has led to an increased overall survival in the metastatic setting. Moreover, novel immune therapies targeting the tumor microenvironment have been developed. In this rapidly evolving treatment landscape, precise tools for personalized cancer therapy are needed. Here, we collected fresh tissue from 42 patients who underwent surgical resection for renal cell carcinoma. Part of the tissue was used to obtain formalin-fixed, paraffin-embedded samples or RNA. The remaining tissue was minced and cultured in a collagen-based three-dimensional, air-liquid interface (ALI) culture system. The generated patient-derived tumor organoids (ALI PDOs) were characterized by immunohistochemistry staining and RNA sequencing to validate their close similarity to the matched tumor. Immune cells and stromal cells within the microenvironment could be identified. Finally, we treated 10 ALI PDOs with the commonly used targeted cancer drug cabozantinib or the ICI nivolumab. Interestingly, we observed varying responses of ALI PDOs to these treatments and future studies are needed to investigate whether the ALI PDO approach could inform about treatment responses in patients. In conclusion, this three-dimensional ccRCC culture model represents a promising, facile tool for monitoring tumor responses to different types of therapies in a controlled manner, yet, still preserves the key features of the tumor of origin.

Mitophagy-associated genes PINK1 and PARK2 are independent prognostic markers of survival in papillary renal cell carcinoma and associated with aggressive tumor behavior.

The aim of this study was to investigate the mitophagy-related genes PINK1 and PARK2 in papillary renal cell carcinoma and their association with prognosis. In silico data of PINK1 and PARK2 were analyzed in TCGA cohorts of papillary renal cell carcinoma comprising 290 tumors and 33 corresponding non-neoplastic renal tissues. Protein expression data from a cohort of 95 papillary renal cell carcinoma patients were analyzed and associated with clinical-pathological parameters including survival. PINK1 and PARK2 were significantly downregulated in papillary renal cell carcinoma at transcript and protein levels. Reduced transcript levels of PINK1 and PARK2 were negatively associated with overall survival (p < 0.05). At the protein level, PARK2 and PINK1 expression were positively correlated (correlation coefficient 0.286, p = 0.04) and reduced PINK1 protein expression was prognostic for shorter survival. Lower PINK1 protein levels were found in tumors with metastases at presentation and in tumors of higher pT-stages. The multivariate analysis revealed mRNA expression of PINK1 and PARK2 as well as PINK1 protein expression as independent prognostic factors for shorter overall survival. The downregulation of PINK1 is a strong predictor of poor survival in papillary renal cell carcinoma. Immunohistochemical PINK1 expression in resected pRCC should be considered as an additional prognostic marker for routine practice.

Targeting glycolysis with 2-deoxy-D-glucose sensitizes primary cell cultures of renal cell carcinoma to tyrosine kinase inhibitors.

PURPOSE: To investigate the synergistic effect of glycolysis inhibition on therapy answer to tyrosine kinase inhibitors in renal carcinoma. METHODS: Primary cell cultures from 33 renal tumors including clear cell RCC (ccRCC), papillary RCC and the rare subtype chromophobe RCC as well as two metastases of ccRCC were obtained and cultivated. The patient-derived cells were verified by immunohistochemistry. CcRCC cells were further examined by exon sequencing of the von Hippel-Lindau gene (VHL) and by RNA-sequencing. Next, cell cultures of all subtypes of RCC were exposed to increasing doses of various tyrosine kinase inhibitors (axitinib, cabozantinib and pazopanib) and the glycolysis inhibitor 2-deoxy-D-glucose, alone or combined. CellTiter-Glo® Luminescence assay and Crystal Violet staining were used to assess the inhibition of glycolysis and the viability of the cultured primary cells. RESULTS: The cells expressed characteristic tissue markers and, in case of ccRCC cultures, the VHL status of the tumor they derived from. An upregulation of HK1, PFKP and SLC2A1 was observed, while components of the respiratory chain were downregulated, confirming a metabolic shift towards aerobic glycolysis. The tumors displayed variable individual responses for the therapeutics. All subtypes of RCC were susceptible to cabozantinib treatment indicated by decreased proliferation. Adding 2-deoxy-D-glucose to tyrosine kinase inhibitors decreased ATP production and increased the susceptibility of ccRCC to pazopanib treatment. CONCLUSION: This study presents a valuable tool to cultivate even uncommon and rare renal cancer subtypes and allows testing of targeted therapies as a personalized approach as well as testing new therapies such as glycolysis inhibition in an in vitro model.