Novel therapeutics for metastatic renal cell carcinoma

MTDH promotes metastasis of clear cell renal cell carcinoma by activating SND1-mediated ERK signaling and epithelial-mesenchymal transition

BACKGROUND

Metastasis is the principal cause of renal cell carcinoma-associated mortality. Metadherin (MTDH) was identified as a vital metastasis driver involved in the metastatic progression of various types of tumors, suggesting that MTDH is a prognostic metastatic biomarker and potential therapeutic target. The role and mechanism of MTDH in the metastatic progression of ccRCC have not yet been adequately explored.

RESULTS

MTDH was remarkably elevated in ccRCC tissues, especially in metastatic ccRCC tissues, compared with normal kidney tissues and correlated with advanced clinicopathological features and poor prognosis. MTDH activated ERK signaling and EMT, thus promoting the migration and invasion of ccRCC cells. The interaction between MTDH and SND1 at the protein level was confirmed using immunoprecipitation and immunofluorescence. Based on the analysis of datasets from GEO and TCGA, SND1 was remarkably increased in ccRCC, especially in metastatic ccRCC, and associated with advanced clinicopathological features and poor prognosis. Knockdown of SND1 mainly abolished the migration and invasion of ccRCC cells by blocking MTDH-mediated ERK and EMT signaling activation.

CONCLUSION

These results revealed that MTDH may be a prognostic metastatic biomarker of ccRCC that promotes ccRCC metastasis by activating SND1-mediated the ERK and EMT signaling pathways. MTDH may serve as an anti-tumor therapeutic target that can be applied for the clinical treatment of metastatic ccRCC.

METHODS

MTDH/SND1 mRNA expression in clear cell renal cell carcinoma (ccRCC) was comprehensively estimated by analysis of GEO-ccRCC and TCGA-KIRC datasets with R software and packages. MTDH protein expression was assessed in a total of 111 ccRCC patients from Peking University First Hospital by immunohistochemistry (IHC). In vitro migration and invasion assays were carried out, and an in vivo metastatic mouse model was developed to investigate the biological functions of MTDH in ccRCC cells. Correlation analysis, immunoprecipitation, western blotting and immunofluorescence were applied to explore the molecular mechanisms of MTDH in ccRCC.

TNIP1 Inhibits Proliferation And Promotes Apoptosis In Clear Cell Renal Carcinoma Through Targeting C/Ebpβ

Background/Purpose

TNF-α-induced protein 3-interacting protein 1 (TNIP1) is active in various cancers, but its expression and function in renal cell carcinoma (RCC) have not been described. This study investigated the role of TNIP1 in clear cell renal cell carcinomas (ccRCC), which accounts for 75–80% of RCC and has a poor prognosis.

Methods

The expression of TNIP1 in human ccRCC tissues and cells was detected by real-time quantitative reverse transcription–polymerase chain reaction (qRT-PCR), Western blot (WB), and immunohistochemical (IHC) staining. Cell proliferation was assayed by a cell counting kit (CCK)-8 assay; cell cycle analysis and apoptosis assay were done by flow cytometry.

Results

TNIP1 is downregulated in both ccRCC human tissues and cells. Besides, TNIP1 downregulation promoted cell proliferation with more cell cycle entry, and inhibited apoptosis. TNIP1 downregulation was associated with increased of expression of the Bcl-2 anti-apoptosis gene and decreased expression of the Bax apoptosis-promoting gene and cleaved-caspase-3 by negatively regulating C/EBPβ expression.

Conclusion

TNIP1 acted as a tumor-inhibitor in ccRCC by targeting C/EBPβ. The results warrant study of TNIP1 as a potential diagnostic marker and therapeutic target of ccRCC.

Homeodomain interacting protein kinase-2 phosphorylates FOXM1 and promotes FOXM1-mediated tumor growth in renal cell carcinoma

Forkhead Box M1 (FOXM1) is a member of the forkhead/winged-helix transcription factors regulating proliferation-associated genes and is critical to DNA replication and mitosis. With this said, the function of FOXM1 in renal cell carcinoma (RCC) has not been clearly elucidated. Thus, in this study, the expression pattern of FOXM1 was significantly upregulated in RCC tissues compared with adjacent noncancerous tissues. Moreover, using liquid chromatography with tandem mass spectrometry (LC-MS/MS), FOXM1 can interact with homeodomain interacting protein kinase-2 (HIPK2). In addition, FOXM1 can be phosphorylated by HIPK2. Furthermore, HIPK2 knockdown inhibits FOXM1 phosphorylation and reduces transcription of FOXM1 associated genes: Cyclin B1 and Aurora B. In addition, HIPK2 knockdown hampers the RCC cells cycle progression and suppresses cell viability in vivo and in vitro. In conclusion, the phosphorylation of FOXM1 by HIPK2 can promote FOXM1 transcription activity and cell proliferation in RCC, thus, indicating a potential mechanism for the treatment of human RCC in the future.

Scutellarin inhibits human renal cancer cell proliferation and migration via upregulation of PTEN

BACKGROUND

Scutellarin is a naturally flavone glycoside that has been shown to exhibit anti-proliferative and anti-apoptotic activities among various human malignancies. However, the anti-cancer effect of Scutellarin in Renal cell carcinoma (RCC) and the underlying mechanism remains unclear.

METHODS AND MATERIALS

RCC cell lines ACHN and 786-O were treated with different concentrations (0-210 μM) of Scutellarin in vitro. Cell viability and proliferation were investigated by MTT and colony formation assays. Cell invasion and migration were detected by Transwell assays. Cell apoptosis and cell cycle distribution was measured by flow cytometry. Western blot was used to investigate the expression levels of crucial proteins. Xenograft tumor model was established to evaluate tumor growth in vivo.

RESULTS

Scutellarin significantly inhibited RCC cell proliferation in a dose- and time- dependent manner. Treatment of RCC cells with Scutellarin (30, 60, and 90 μM) markedly induced apoptosis and cell cycle arrested at G0/G1 phase in a concentration-dependent characteristic. Cell invasion and migration capacities of RCC cells were also dose-dependently suppressed by Scutellarin treatment. Western blot assays revealed that the crucial proteins including cyclin D1, CDK2, Bcl2, MMP-2, and MMP-9 were significantly reduced while Bax, cleaved caspase 3 and p21 were increased by Scutellarin in RCC cells. In vivo assay indicated that Scutellarin possessed anti-cancer effect on xenograft without triggering toxic effect. Mechanically, Scutellarin dramatically increased the protein level of phosphatase and tensin homologue (PTEN) and inhibited the activity of P13K/AKT/mTOR signaling. Ectopic expression of PTEN enhanced the inhibitory effect of Scutellarin on RCC proliferation while knockdown of PTEN abrogated it through regulating its downstream P13K/AKT/mTOR signaling pathway.

CONCLUSION

Scutellarin inhibited RCC cell proliferation and invasion partially by enhancing the expression of PTEN through inhibition of P13K/AKT/mTOR pathway, suggesting that Scutellarin might serve as a potential therapeutic agent in RCC treatment.

ARHGAP24 inhibits cell cycle progression, induces apoptosis and suppresses invasion in renal cell carcinoma

Renal cell carcinoma (RCC) is the major cause of kidney malignancy-related deaths. Rho GTPases are key regulators in cancer cell metastasis. ARHGAP24, a Rac-specific member of the Rho GTPase-activating protein family, acts as a functional target of cancer cell migration and invasion. In the present study, we identified ARHGAP24 expression is downregulated in renal cancer tissues and is highly correlated with long-term survival in RCC patients. Therefore, we investigated the biological functions of ARHGAP24 in renal cancer cells. Ectopic expression of ARHGAP24 resulted in inhibited cell proliferation and arrested cell cycle in two renal cancer cell lines (786-0 and Caki-2); the results were confirmed by ARHGAP24 knocking down. In addition, ARHGAP24 significantly reduced the cell invasion ability and induced apoptosis in renal cancer cells. In addition, overexpressing ARHGAP24 impaired tumor formation in vivo. In summary, our results illustrated that ARHGAP24 plays a unique role in RCC progression as a tumor repressor.

Sequential targeted therapy after pazopanib therapy in patients with metastatic renal cell cancer: efficacy and toxicity

INTRODUCTION/BACKGROUND

Patients with metastatic renal cell carcinoma (mRCC) in whom first-line therapies have failed might derive clinical benefit with sequential targeted agents. Limited data are available on the efficacy and toxicity of subsequent therapies after disease progression during pazopanib therapy.

PATIENTS AND METHODS

Patients with mRCC who received subsequent systemic treatment after pazopanib treatment failure were identified across 7 institutions. Pazopanib was given as first-line therapy in 28 patients and after cytokines therapy in 7 patients. Clinical outcome and toxicity analyses of 2 sequential treatment options (anti-vascular endothelial growth factor [VEGF] or mammalian target of rapamycin inhibitor [mTORi]) is presented.

RESULTS

Subsequent therapy was anti-VEGF in 22 patients and mTORi in 13. One patient who received bevacizumab and temsirolimus combination was excluded. VEGF-targeted therapies included sorafenib (n = 10), sunitinib (n = 3), bevacizumab (n = 2), cediranib (n = 4) and cabozantinib (n = 3). Patients treated with mTORi received everolimus. Median progression-free survival was 5.6 months from the start of subsequent therapy with anti-VEGF and 2.4 months with mTORi (P = .009). Overall survival (OS) was not significantly different (P = .68). Clinical benefit (including partial response and stable disease) on subsequent therapy was observed in 15 patients (64%) and 4 patients (31%) of anti-VEGF- and everolimus-treated patients, respectively (P = .021).

CONCLUSION

In this retrospective study, targeting VEGF was an effective strategy after disease progression during pazopanib treatment, although OS was not different among patients treated with VEGF or mTORi.

Prognostic factors associated with the response to sunitinib in patients with metastatic renal cell carcinoma

OBJECTIVE

We investigated the prognostic clinicopathologic factors associated with overall survival (os) and progression-free survival (pfs) in the once-daily continuous administration of first-line sunitinib in a consecutive cohort of Turkish patients with metastatic renal cell carcinoma (rcc).

METHODS

The study enrolled 77 Turkish patients with metastatic rcc who received sunitinib in a continuous once-daily dosing regimen between April 2006 and April 2011. Univariate analyses were performed using the log-rank test.

RESULTS

Median follow-up was 18.5 months. In univariate analyses, poor pfs and os were associated with 4 of the 5 factors in the Memorial Sloan-Kettering Cancer Center (mskcc) score: Eastern Cooperative Oncology Group performance status of 2 or higher, low hemoglobin, high corrected serum calcium, and high lactate dehydrogenase. In addition to those factors, hypoalbuminemia, more than 2 metastatic sites, liver metastasis, non-clear cell histology, and the presence of sarcomatoid features on pathology were also associated with poor pfs; and male sex, hypoalbuminemia, prior radiotherapy, more than 2 metastatic sites, lung metastasis, nuclear grade of 3 or 4 for the primary tumour, and the presence of sarcomatoid features were also associated with poorer os. The application of the mskcc model distinctly separated the pfs and os curves (p < 0.001).

CONCLUSIONS

Our study identified prognostic factors for pfs and os with the use sunitinib as first-line metastatic rcc therapy and confirmed that the mskcc model still appears to be valid for predicting survival in metastatic rcc in the era of molecular targeted therapy.

Clinical efficacy and prognostic factors for overall survival in Japanese patients with metastatic renal cell cancer treated with sunitinib

Study Type--Therapy (case series). Level of Evidence 4. What's known on the subject? and What does the study add? A randomized prospective phase III clinical trial for systemic treatment-naïve metastatic renal cell cancer (RCC) patients demonstrated the superiority of sunitinib over interferon with an acceptable safety profile. However, a commonly asked question is whether patients with RCC in clinical trials are representative of those with this disease being seen in ordinary clinical practice. To our knowledge, this is the first report of sunitinib for the Japanese patients with metastatic RCC in ordinary clinical practice. The estimated median PFS and OS in this study were 9.3 and 32.2 months, respectively. The application of the MSKCC model distinctly separated OS curves (P<0.001), suggesting that MSKCC prognostic factors might be still valid to predict survival in metastatic RCC in the era of molecular targeted therapy.

OBJECTIVES

• To report the treatment efficacy and safety profile of sunitinib for patients with metastatic renal cell carcinoma (RCC) in ordinary clinical practice. • In addition, to investigate the prognostic clinicopathological factors in these patients.

PATIENTS AND METHODS

• The present study consisted of native Japanese patients with metastatic RCC, comprising 29 pretreated and 34 systemic treatment-naïve patients. • Univariate and multivariate analyses were performed by the log-rank test and the Cox proportional hazards model, respectively.

RESULTS

• Estimated median progression-free survival and overall survival (OS) were 9.3 months (95% confidence interval, CI, 5.0-13.7) and 32.2 months (95% CI, 24.4-40.0), respectively. • Among the patients pretreated before sunitinib, two patients were treated with initialized systemic therapy with sorafenib and the remaining 27 were initialized with interferon-α. • The OS from the initial systemic therapy of the patients in pretreated groups was 79.6 months (95% CI, 14.6-144.5). • The application of the Memorial Sloan-Kettering Cancer Center model distinctly separated the OS curves (P < 0.001). • The most common grade 3 adverse events were fatigue (53%), thrombocytopaenia (48%), hand-foot syndrome (16%), anaemia (20%), hypertension (10%) and leucopaenia (9%), although these events were manageable and reversible.

CONCLUSIONS

• Sunitinib has a favourable efficacy/safety profile for Japanese metastatic RCC patients in clinical practice. • The estimated median OS was >2 years with acceptable tolerability. • The median OS from the initial systemic therapy of the pretreated patients was >6 years. • Memorial Sloan-Kettering Cancer Center prognostic factors still appear to be valid for predicting survival in metastatic RCC in the era of molecular targeted therapy.

Characterization and targeting of phosphatidylinositol-3 kinase (PI3K) and mammalian target of rapamycin (mTOR) in renal cell cancer

Background

PI3K and mTOR are key components of signal transduction pathways critical for cell survival. Numerous PI3K inhibitors have entered clinical trials, while mTOR is the target of approved drugs for metastatic renal cell carcinoma (RCC). We characterized expression of p85 and p110α PI3K subunits and mTOR in RCC specimens and assessed pharmacologic co-targeting of these molecules in vitro.

Methods

We employed tissue microarrays containing 330 nephrectomy cases using a novel immunofluorescence-based method of Automated Quantitative Analysis (AQUA) of in situ protein expression. In RCC cell lines we assessed synergism between PI3K and mTOR inhibitors and activity of NVP-BEZ235, which co-targets PI3K and mTOR.

Results

p85 expression was associated with high stage and grade (P < 0.0001 for both). High p85 and high mTOR expression were strongly associated with decreased survival, and high p85 was independently prognostic on multi-variable analysis. Strong co-expression of both PI3K subunits and mTOR was found in the human specimens. The PI3K inhibitor LY294002 and rapamycin were highly synergistic in all six RCC cell lines studied. Similar synergism was seen with all rapamycin concentrations used. NVP-BEZ235 inhibited RCC cell growth in vitro with IC₅₀s in the low ηM range and resultant PARP cleavage.

Conclusions

High PI3K and mTOR expression in RCC defines populations with decreased survival, suggesting that they are good drug targets in RCC. These targets tend to be co-expressed, and co-targeting these molecules is synergistic. NVP-BEZ235 is active in RCC cells in vitro; suggesting that concurrent PI3K and mTOR targeting in RCC warrants further investigation.

DW-MRI of the urogenital tract: applications in oncology

Diffusion-weighted magnetic resonance imaging (DW-MRI) appears to hold promise as a non-invasive imaging modality in the detection of early microstructural and functional changes of different organs. DW-MRI is an imaging technique with a high sensitivity for the detection of a large variety of diseases in the urogenital tract. In kidneys, DW-MRI has shown promise for the characterization of solid lesions. Also in focal T1 hyperintense lesions DW-MRI was able to differentiate hemorrhagic cysts from tumours according to the lower apparent diffusion coefficient (ADC) values reported for renal cell carcinomas. Promising results were also published for the detection of prostate cancer. DW-MRI applied in addition to conventional T2-weighted imaging has been found to improve tumour detection. On a 3 T magnetic resonance unit ADC values were reported to be lower for tumours compared with the normal-appearing peripheral zone. The combined approach of T2-weighted imaging and DW-MRI also showed promising results for the detection of recurrent tumour in patients after radiation therapy. DW-MRI may improve the performance of conventional T2-weighted and contrast-enhanced MRI in the preoperative work-up of bladder cancer, as it may help in distinguishing superficial from muscle invasive bladder cancer, which is critical for patient management. Another challenging application of DW-MRI in the urogenital tract is the detection of pelvic lymph node metastases. As the ADC is generally reduced in malignant tumours and increased under inflammatory conditions, reduced ADC values were expected in patients with lymph node metastases.

Renal cell carcinoma

Renal Cell Carcinoma (RCC) has the highest mortality rate of the genitourinary cancers and the incidence of RCC has risen steadily. If detected early, RCC is curable by surgery although a minority are at risk of recurrence. Increasing incidental detection and an ageing population has led to active surveillance as an option for patients with small renal masses. RCC is heterogeneous and comprises several histological cell types with different genetics, biology and behavior. The identification of the genes predisposing to inherited syndromes with RCC has provided much of our knowledge of the molecular basis of early sporadic RCC. Many of the oncogenes and tumor suppressor genes that are mutated leading to pathway dysregulation in RCC remain to be elucidated. Global studies of copy number, gene sequencing, gene expression, miRNA expression and gene methylation in primary RCC will lead towards this goal. The natural history of RCC indicated by candidate precursor lesions, multifocal or bilateral disease, growth rate of small renal masses under surveillance, and high risk populations provide insight into the behavior of this disease. The use of molecular markers for early detection and prognosis merits more attention with ongoing advances in omics technologies. This review focuses on early RCC, that is disease confined within the renal capsule.