Review on targeted treatment of patients with advanced-stage renal cell carcinoma: a medical oncologist's perspective

Expression of PTEN-long nephritis and its effect on renal inflammation

Based on the important functions of phosphatase and tensin homolog (PTEN)-Long for renal diseases, the present study aimed to investigate the expression of PTEN-Long in patients and mice with nephritis and its effect on nephritis. Expression levels of PTEN-Long in serum of patients with nephritis, renal cell carcinoma (RCC) as well as normal controls, and in serum and renal tissues of mice were measured by western blotting. PTEN-Long knock-in and knock-out mice were constructed via the CRISPR-Cas9 technique. Intraperitoneal injection of lipopolysaccharide+renal homogenate was performed to construct a mouse nephritis model. Mice were divided into control group, model group, knock-in group and knock-out group. A Bio-Plex system was used to detect secretion of serum inflammatory factors. Expression of inflammatory factors in renal tissues of different groups was detected by reverse transcription semi-quantitative polymerase chain reaction. Hematoxylin and eosin staining was used to observe the pathological changes of renal tissue. PTEN-Long was downregulated in patients with nephritis and RCC compared with controls, whereas the expression levels of inflammatory factors were increased. PTEN-long knock-in significantly reduced the serum content and expression levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-1β and IL-18. PTEN-long knock-out also decreased the expression levels of TNF-α and IL-6 but exhibited no effects on expression of IL-1β and IL-18. Compared with knock-out and model groups, renal tissue inflammation was significantly reduced in knock-in group. The protein level of PTEN-Long was significantly lower in serum than in renal tissue. These findings suggest that PTEN-long can inhibit the progression of nephritis by interacting with inflammatory factors to protect kidney.

ST6Gal-I predicts postoperative clinical outcome for patients with localized clear-cell renal cell carcinoma

Hyperactivated α2-6-sialylation on N-glycans due to overexpression of the Golgi enzyme β-galactoside: α2-6- sialyltransferase (ST6Gal-I) often correlates with cancer progression, metastasis, and poor prognosis. This study was aimed to determine the association between ST6Gal-I expression and the risk of recurrence and survival of patients with localized clear-cell renal cell carcinoma (ccRCC) following surgery. We retrospectively enrolled 391 patients (265 in training cohort and 126 in validation cohort) with localized ccRCC underwent nephrectomy at a single center. Tissue microarrays were constructed for immunostaining of ST6Gal-I. Prognostic value and clinical outcomes were evaluated. High ST6Gal-I expression was associated with Fuhrman grade (p<0.001 and p=0.016, respectively) and the University of California Los-Angeles Integrated Staging System (UISS) score (p=0.004 and p=0.017, respectively) in both cohorts. Patients with high ST6Gal-I expression had significantly worse overall survival (OS) (p<0.001 and p<0.001, respectively) and recurrence free survival (RFS) (p<0.001 and p=0.002, respectively) than those with low expression in both cohorts. On multivariate analysis, ST6Gal-I expression remained associated with OS and RFS even after adjusting for the UISS score. Stratified analysis suggested that the association is more pronounced among patients with low and intermediate-risk disease defined by the UISS score. High ST6Gal-I expression is a potential independent adverse predictor of survival and recurrence in ccRCC patients, and the prognostic value is most prominent in those with low and intermediate-risk disease defined by the UISS score.

Heat-shock protein 70 as a tumor antigen for in vitro dendritic cell pulsing in renal cell carcinoma cases

Immunological functions of heat shock proteins (HSPs) have long been recognized. In this study we aimed to efficiently purify HSP70 from renal cell carcinoma and test it as a tumor antigen for pulsing dendritic cells in vitro. HSP70 was purified from renal cell carcinoma specimens by serial column chromatography on Con A-sepharose, PD-10, ADP-agarose and DEAE-cellulose, and finally subjected to fast protein liquid chromatography (FPLC). Dendritic cells derived from the adherent fraction of peripheral blood mononuclear cells were cultured in the presence of IL-4 and GM-CSF and exposed to tumor HSP70. After 24 hours, dendritic cells were phenotypically characterized by flow cytometry. T cells obtained from the non-adherent fraction of peripheral blood mononuclear cells were then co-cultured with HSP70-pulsed dendritic cells and after 3 days T cell cytotoxicity towards primary cultured renal cell carcinoma cells was examined by Cell Counting Kit-8 assay. Dendritic cells pulsed in vitro with tumor-derived HSP70 expressed higher levels of CD83, CD80, CD86 and HLA-DR maturation markers than those pulsed with tumor cell lysate and comparable to that of dendritic cells pulsed with tumor cell lysate plus TNF-α. Concomitantly, cytotoxic T-lymphocytes induced by HSP70-pulsed dendritic cells presented the highest cytotoxic activity. There were no significant differences when using homologous or autologous HSP70 as the tumor antigen. HSP70 can be efficiently purified by chromatography and induces in vitro dendritic cell maturation in the absence of TNF-α. Conspecific HSP70 may effectively be used as a tumor antigen to pulse dendritic cells in vitro.

Targeting EGFL7 expression through RNA interference suppresses renal cell carcinoma growth by inhibiting angiogenesis

Renal cell carcinoma (RCC) is the most lethal of all urological cancers and tumor angiogenesis is closely related with its growth, invasion, and metastasis. Recent studies have suggested that epidermal growth factor-like domain multiple 7 (EGFL7) is overexpressed by many tumors, such as colorectal cancer and hepatocellular carcinoma; it is also correlated with progression, metastasis, and a poor prognosis. However, the role of EGFL7 in RCC is not clear. In this study, we examined how EGFL7 contributes to the growth of RCC using a co-culture system in vitro and a xenograft model in vivo. Downregulated EGFL7 expression in RCC cells affected the migration and tubule formation of HMEC-1 cells, but not their growth and apoptosis in vitro. The level of focal adhesion kinase (FAK) phosphorylation in HMEC-1 cells decreased significantly when co-cultured with 786-0/iEGFL7 cells compared with 786-0 cells. After adding rhEGFL7, the level of FAK phosphorylation in HMEC-1 cells was significantly elevated compared with phosphate-buffered saline (PBS) control. However, FAK phosphorylation was abrogated by EGFR inhibition. The average size of RCC local tumors in the 786-0/iEGFL7 group was noticeably smaller than those in the 786-0 cell group and their vascular density was also significantly decreased. These data suggest that EGFL7 has an important function in the growth of RCC by facilitating angiogenesis.

Phosphorylated signal transducer and activator of transcription 1 is a potential predictor of interferon response in patients with advanced renal cell carcinoma

The present study aimed to evaluate the expression status of Janus kinase (JAK)-Signal Transducer and Activator of Transcription (STAT) in renal cell carcinoma and benign renal tissue, and identify a potential biomarker for interferon (IFN) response prediction. A total of 32 specimens of human renal cell carcinoma and 10 specimens of benign renal tissue were harvested from surgically removed kidneys. The expression levels of JAK‑STAT were determined by immunohistochemical staining and quantitative polymerase chain reaction. Furthermore, the expression levels of JAK‑STAT in renal cell carcinoma tissues that were stimulated with IFN-α were quantified by western blot analysis. The positive expression rates of JAK1, STAT1 and phosphorylated (P)‑STAT1 in the renal cell carcinomas were significantly lower than that in the benign renal tissues (25.0, 31.2, and 12.5% vs. 70.0, 50.0, and 70.0%, respectively; P<0.05). The relative expression levels of JAK1 (0.696 ± 0.102) and STAT1 mRNA (0.341 ± 0.068) in the tumor tissue were lower than those in the benign tissue (0.957 ± 0.103 and 0.547 ± 0.082, respectively; P<0.05). IFN stimulation enhanced the expression levels of P‑STAT1 in the renal cell carcinoma tissues, and enhancement of the P‑STAT1 expression levels was associated with tumor relapse and metastasis. In conclusion, P‑STAT1 is a potential predictor of IFN response in patients with advanced renal cell carcinoma.