Kan Gong

MiR-30d induces apoptosis and is regulated by the Akt/FOXO pathway in renal cell carcinoma

MicroRNAs (miRNAs) play critical roles in tumorigenesis by modulating the expression of target gene mRNAs. However, their role in cell signaling is not well defined. In this study, we identified miR-30d as a downstream effector of the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway in renal cell carcinoma (RCC) cells. We show that Akt inhibition transcriptionally up-regulates miR-30d expression through activation of the transcription factor forkhead box O (FOXO) 3A. Functional analysis revealed that miR-30d overexpression suppresses cell proliferation and induces apoptosis in RCC cells, suggesting that miR-30d acts as a tumor suppressor. In searching for downstream targets of miR-30d, we found that miR-30d post-transcriptionally suppresses expression of the oncoprotein metadherin (MTDH) by destabilizing its mRNA. Furthermore, we found that FOXO down-regulates MTDH expression through up-regulating expression of miR-30d. Thus, our findings reveal a new Akt/FOXO/miR-30d/MTDH signaling transduction pathway and identify miR-30d as a tumor suppressor, providing a new potential target for the treatment of RCC.

Extramammary Paget's disease of scrotum--report of 25 cases and literature review.

OBJECTIVES We evaluate the clinical manifestations, management, and prognostic characteristics of scrotal extramammary Pagets disease (EMPD). METHODS The study comprised 25 patients with scrotal EMPD at our institute from January 1982 to February 2005, with all available clinical and pathological data reviewed. RESULTS Of these 25 patients, 1 received radiotherapy and 24 received local wide excisions. In 24 operated patients, 7 had local recurrence and/or metastasis of groin lymph node. Five of the 7 with recurrence had a positive surgical margin postoperatively and they received a second local extensive excision. One of the 7 with recurrence and metastasis of the groin lymph node had a second local extensive excision with groin lymphadenectomy, and the last one who only had metastasis of the groin lymph node had a groin lymphadenectomy. Four of 13 patients with dermal invasion by Pagets cell had metastasis. None of the other 12 patients without dermal invasion had metastasis. However, there was no statistical metastasis rate difference (P = 0.096) between the patients with dermal invasion by Pagets cell and without. There was no statistical difference (P = 0.947) in mean delay time from onset of symptoms to diagnosis between the 2 groups either. The follow-up duration varies from 17 to 243 months (mean 119 + 86.2 months). One patient with stage D died of EMPD of the scrotum. CONCLUSIONS We found that EMPD of the scrotum is usually a slow progressive disease, mainly seen in elderly patients, and has a good prognosis when there is noninvasive disease. The primary treatment for EMPD of the scrotum is wide surgical excision. The key to decreasing tumor recurrence, however, is a precise, preoperative histological examination to define the range of the lesion.

The Erythropoietin/Erythropoietin Receptor Signaling Pathway Promotes Growth and Invasion Abilities in Human Renal Carcinoma Cells

Co-expression of erythropoietin (Epo) and erythropoietin receptor (EpoR) has been found in various non-hematopoietic cancers including hereditary and sporadic renal cell carcinomas (RCC), but the Epo/EpoR autocrine and paracrine mechanisms in tumor progression have not yet been identified. In this study, we used RNA interference method to down-regulate EpoR to investigate the function of Epo/EpoR pathway in human RCC cells. Epo and EpoR co-expressed in primary renal cancer cells and 6 human RCC cell lines. EpoR signaling was constitutionally phosphorylated in primary renal cancer cells, 786-0 and Caki-1 cells, and recombinant human Epo (rhEpo) stimulation had no significant effects on further phosphorylation of EpoR pathway, proliferation, and invasiveness of the cells. Down-regulation of EpoR expression in 786-0 cells by lentivirus-introduced siRNA resulted in inhibition of growth and invasiveness in vitro and in vivo, and promotion of cell apoptosis. In addition, rhEpo stimulation slightly antagonized the anti-tumor effect of Sunitinib on 786-0 cells. Sunitinib could induce more apoptotic cells in 786-0 cells with knockdown EpoR expression. Our results suggested that Epo/EpoR pathway was involved in cell growth, invasion, survival, and sensitivity to the multi-kinases inhibitor Sunitinib in RCC cells.

Coexpression of erythopoietin and erythopoietin receptor in sporadic clear cell renal cell carcinoma.

Clear cell renal cell carcinoma (CCRCC) is the most common renal carcinoma and it is often associated with von Hippel-Lindau disease (VHL) gene mutations. CCRCCs with VHL mutations demonstrate hypoxia-inducible factor (HIF) overexpression as well as increased expression of vascular endothelial growth factor (VEGF). Recently, the erythropoietin (Epo) has been found to be upregulated in renal and other tumors associated with VHL disease. Furthermore, Epo and Epo receptor (EpoR) coexpression has also been reported in these tumors. The results provided strong evidence that an autocrine loop is involved in tumorigenesis in VHL disease. We investigated whether Epo and EpoR coexpression also occurs in sporadic CCRCC. Fifty-four sporadic CCRCCs were analyzed. VHL gene mutations were detected in 30 out of 54 tumors. Coexpression of Epo and EpoR was detected in 50 out of 54 tumors regardless of their VHL mutation status. The results suggest that coexpression of Epo and EpoR plays an important role in tumorigenesis of sporadic CCRCC.

Incidence, characteristics, treatment strategies, and oncologic outcomes of synchronous bilateral upper tract urothelial carcinoma in the Chinese population

OBJECTIVES To investigate the incidence and treatment strategies for bilateral upper tract urothelial carcinoma (UTUC) and to compare the characteristic and oncologic outcomes of bilateral UTUC with those of unilateral tumors. METHODS AND MATERIALS The study included 892 consecutive patients with UTUC. Bilateral UTUC was defined as synchronous bilateral carcinoma on preoperative imaging before confirmation by pathology or positive urine cytology result plus direct visualization. Radical nephroureterectomy (RNU) or nephron-sparing surgery (NSS) or both were carried out. RESULTS A total of 39 patients (4.37%) suffered from bilateral disease. Discordant histological grade of bilateral tumor was found in 39.3% cases. Bilateral tumors were associated with female sex (P<0.001), preoperative renal insufficiency (P<0.001), previous or concomitant bladder tumors (P = 0.013), lower tumor stages (P = 0.020), papillary architecture (P = 0.001), and smaller-sized tumors (P = 0.020). Patients with worse renal function (P<0.001) or large-sized tumors (P = 0.039) tended to be treated with bilateral RNU. Most patients (67.6%) were treated with unilateral RNU plus unilateral NSS, with NSS being performed on tumors that only extended to the ureter (P = 0.003) and had a smaller size (P = 0.005). The median follow-up duration was 56 months. The 5-year cancer-specific survival and bladder recurrence-free survival rates were 81.2% and 64.5%, respectively, similar to those of unilateral tumors. Male sex (hazard ratio = 11.535) and higher tumor stage (hazard ratio = 3.386) were independent worse prognostic factors. CONCLUSIONS The prevalence of bilateral UTUC is rare. Female patients, patients with renal insufficiency, and those with bladder tumor tended to suffer from bilateral disease and were less likely to present with worse pathological outcomes in the Chinese population. The tumor characteristics and renal function were informative in treatment selection. The oncologic outcomes were similar to those in unilateral UTUC, and male sex and a higher tumor stage were poor prognostic factors for these patients.

Prognostic and predictive value of epigenetic biomarkers and clinical factors in upper tract urothelial carcinoma.

AIM We conducted this study to identify gene promoter methylation status and clinical predictors for upper tract urothelial carcinoma (UTUC) patients. MATERIALS & METHODS Using methylation-sensitive PCR, we examined ten genes promoter methylation status in 687 UTUC patients. RESULTS A methylated promoter of three genes to predict higher tumor stage (T3 and T4), five genes to predict higher tumor grade (G3) and one gene to predict pN+ were certified in this study. Nine factors were significantly associated with poor cancer-specific survival. Six factors were considered as predictors to develop bladder recurrence after surgery. CONCLUSION Methylation occurs commonly in UTUCs, may affect carcinogenic mechanisms, and is a well predictive factor for cancer-specific survival and bladder recurrence in UTUCs.

Telomere Shortening Is Associated with Genetic Anticipation in Chinese Von Hippel–Lindau Disease Families

Von Hippel-Lindau (VHL) disease is a rare autosomal dominant cancer syndrome. A phenomenon known as genetic anticipation has been documented in some hereditary cancer syndromes, where it was proved to relate to telomere shortening. Because studies of this phenomenon in VHL disease have been relatively scarce, we investigated anticipation in 18 Chinese VHL disease families. We recruited 34 parent-child patient pairs (57 patients) from 18 families with VHL disease. Onset age was defined as the age when any symptom or sign of VHL disease first appeared. Anticipation of onset age was analyzed by paired t test and the other two special tests (HV and RY2). Relative telomere length of peripheral leukocytes was measured in 29 patients and 325 healthy controls. Onset age was younger in child than in parent in 31 of the 34 parent-child pairs. Patients in the first generation had older onset age with longer age-adjusted relative telomere length, and those in the next generation had younger onset age with shorter age-adjusted relative telomere length (P < 0.001) in the 10 parent-child pairs from eight families with VHL disease. In addition, relative telomere length was shorter in the 29 patients with VHL disease than in the normal controls (P = 0.003). The anticipation may relate to the shortening of telomere length in patients with VHL in successive generations. These findings indicate that anticipation is present in families with VHL disease and may be helpful for genetic counseling for families with VHL disease families and for further understanding the pathogenesis of VHL disease.

Mosaicism in von Hippel–Lindau disease with severe renal manifestations

von Hippel–Lindau (VHL) disease is an inheritable multisystem tumor syndrome characterized by multiple benign and malignant tumors affecting multiple organs. VHL is the result of a germline mutation in the VHL tumor suppressor gene. Molecular genomic analysis routinely confirms the clinical diagnosis. However, the use of molecular diagnostic methods can often be insufficient for the detection of mosaic germline VHL mutations, making the diagnosis of some cases of VHL difficult. Here, we report the case of a VHL mosaic patient with bilateral renal lesions in the absence of other VHL‐associated lesions. A VHL mutation was not originally detected by routine molecular testing. Nonetheless, the detection of a heterozygous c.194C>G (p.Ser65Trp) VHL mutation in the patients daughter prompted further genetic assessment and eventually resulted in the finding of a mosaic c.194C>G (p.Ser65Trp) VHL mutation in the patient. The mutation rate was 18.8 ± 3.84% in peripheral leukocytes. As the frequency of VHL mosaicism remains underdetermined, the possibility of a diagnosis of mosaic VHL should be considered in patients with both typical and atypical VHL‐associated manifestations.

CSTP1, a novel protein phosphatase, blocks cell cycle, promotes cell apoptosis, and suppresses tumor growth of bladder cancer by directly dephosphorylating Akt at Ser473 site.

Akt/protein kinase B is a pivotal component downstream of phosphatidylinositol 3-kinase (PI3K) pathway, whose activity regulates the balance between cell survival and apoptosis. Phosphorylation of Akt occurs at two key sites either at Thr308 site in the activation loop or at Ser473 site in the hydrophobic motif. The phosphorylated form of Akt (pAkt) is activated to promote cell survival. The mechanisms of pAkt dephosphorylation and how the signal transduction of Akt pathway is terminated are still largely unknown. In this study, we identified a novel protein phosphatase CSTP1(complete s transactivated protein 1), which interacts and dephosphorylates Akt specifically at Ser473 site in vivo and in vitro, blocks cell cycle progression and promotes cell apoptosis. The effects of CSTP1 on cell survival and cell cycle were abrogated by depletion of phosphatase domain of CSTP1 or by expression of a constitutively active form of Akt (S473D), suggesting Ser473 site of Akt as a primary cellular target of CSTP1. Expression profile analysis showed that CSTP1 expression is selectively down-regulated in non-invasive bladder cancer tissues and over-expression of CSTP1 suppressed the size of tumors in nude mice. Kaplan-Meier curves revealed that decreased expression of CSTP1 implicated significantly reduced recurrence-free survival in patients suffered from non-invasive bladder cancers.

Intra-tumour molecular heterogeneity of clear cell renal cell carcinoma reveals the diversity of the response to targeted therapies using patient-derived xenograft models

Inter- and intra-tumour molecular heterogeneity is increasingly recognized in clear cell renal cell carcinoma (ccRCC). It may partially explain the diversity of responses to targeted therapies and the various clinical outcomes. In this study, a 56-year-old male ccRCC patient with multiple metastases received radical nephrectomy and resection of the metastatic tumour in chest wall. The surgical specimens were implanted into nude mice to establish patient-derived xenograft (PDX) models with KI2367 model derived from the primary tumour and KI2368 model from the metastastic tumour. The two modles were treated with Sorafenib, Sunitinib, Axitinib, combined Sorafenib/Sunitinib, or alternating therapy of Sorafenib and Sunitinib. Significant anti-tumour activity was found in KI2367 treated with Sorafenib/Sunitinib monotherapy, combined Sorafenib/Sunitinib, and alternating therapy of Sorafenib/Sunitinib (P<0.05) but not in that treated with Axitinib monotherapy. In contrast, KI2368 was significantly responsive to Sunitinib monotherapy, combined Sorafenib/Sunitinib therapy and alternating therapy of Sorafenib/Sunitinib but not responsive to Sorafenib and Axitinib monotherapy (P<0.05). RNAseq of the two models demonstrated that the expression levels of 1,725 genes including the drug targeted genes of PDGFA, PDGFB and PDGFRA were >5-fold higher in KI2367 than in KI2368 and the expression levels of 994 genes were > 5-fold higher in KI2368 than in KI2367. These results suggest the presence of intra-tumour molecular heterogeneity in this patient. This heterogeneity may influence the response to targeted therapies. Multiple biopsy, liquid biopsy and genomic analysis of intra- tumour molecular heterogeneity may help guide a more precise and effective plan in selecting targeted therapies for ccRCC patients.