TFE3-renal carcinoma in an adult patient: A case with strong expression of phosphorylated hepatocyte growth factor (HGFR)/Met

Retracted Article: RNA-sequencing identified miR-3681 as a negative regulator in the proliferation and migration of cervical cancer cells via the posttranscriptional suppression of HGFR

In this study, RNA-sequencing was used to investigate the differentially expressed miRNAs between cervical cancer tissues and matched adjacent non-tumor tissues. Five miRNAs were sharply downregulated in the cancer tissue, including miR-199a, miR-22, miR-615, miR-3681-3p (miR-3681), and miR-1193. Among them, miR-3681 was uncharacterized. The results from qPCR analysis showed that miR-3681 expression was decreased in patients with cervical cancer compared with the control, and decreased in the human cervical cancer cell lines SiHa, HeLa, C4-1, C-33A and Caski, compared with the normal human cervical epithelial cell line HCerEpic. Then, different concentrations of miR-3681 mimic and miR-3681 inhibitor were respectively transfected into the human cervical cancer cell line C-33A, and the expression of miR-3681, cell proliferation, cell apoptosis and cell migration were measured after 48 h. The results showed that the miR-3681 mimic increased the miR-3681 level, suppressed cell proliferation and migration, and induced cell apoptosis in a dose-dependent manner. In contrast, the miR-3681 inhibitor decreased the miR-3681 level, promoted cell proliferation and migration, and inhibited cell apoptosis in a dose-dependent manner. Moreover, bioinformatics analysis showed that there was a miR-3681 binding site in the mRNA 3'UTR of HGFR, which was robustly upregulated in cervical cancer cell lines compared with HCerEpic cells. In addition, luciferase activity analysis demonstrated that miR-3681 could directly target HGFR, which promoted the proliferation and migration of C-33A cells via activation of the PI3K/Akt pathway in a dose-dependent manner. Furthermore, our results showed that knockdown of HGFR could antagonize the promotion of anti-miR-3681 on the activation of the PI3K/Akt pathway and cell proliferation and migration. In conclusion, MiR-3681 was identified as a negative regulator in the proliferation and migration of cervical cancer cells. This function is associated with the posttranscriptional suppression of HGFR and the deactivation of the PI3K/Akt pathway.

Rapidly progressing renal cell carcinoma associated with Xp11.2 translocations: a case report

Introduction

Renal cell carcinoma associated with Xp11.2 translocations is frequently reported in children, but adult-onset is rare. Here, the case of an adult male who developed a renal cell carcinoma associated with Xp11.2 translocations is presented.

Case presentation

A 38-year-old Asian man presented with left back pain and macroscopic hematuria. Computed tomography revealed a left renal tumor (T3N2M0), and a left radical nephrectomy was performed. Hematoxylin-eosin staining revealed papillary architecture and clear or eosinophilic cytoplasm, and the diagnosis of renal cell carcinoma associated with Xp11.2 translocations/TFE3 gene fusion was made by the immunohistochemical determination of transcription factor E3 protein. In spite of adjuvant therapy with α-interferon, a recurrent tumor was found in his left lung by computed tomography three months after the nephrectomy. Interleukin-2, tyrosine kinase inhibitors and mammalian target of rapamycin inhibitors showed no effect on tumor progression.

Conclusions

Renal cell carcinomas associated with Xp11.2 translocations have an aggressive clinical course in adults. Strict diagnosis using the immunohistochemistry of transcription factor E3 protein is important to predict the prognosis of such patients and new strategies need to be determined to treat patients with these tumors

Receptor tyrosine kinases: from biology to pathology

Receptor tyrosine kinases (RTKs) are transmembrane proteins involved in the control of fundamental cellular processes in metazoans. RTKs possess a general structure that includes an extracellular domain, a transmembrane domain and a highly conserved tyrosine kinase domain. RTKs are classified according to their variable extracellular ligand-binding domain. Studies of human RTK members have yielded a wealth of information elucidating their importance. Improper functioning of these enzymes due to mutations, mainly in the kinase domain, is often manifested in various human diseases and is known to be involved in several types of cancer. Here we summarize most of human RTKs, their cognate ligands, as well as related diseases and discuss the eventual use of certain RTKs as new therapeutic targets.

Targeting the Met signaling pathway in renal cancer

Renal cell carcinoma (RCC), the most common form of kidney cancer, accounts for 3% of all adult malignancies and its incidence has significantly increased over the last 20 years. RCC claims 13,000 lives annually in the USA and more than 100,000 worldwide. A better understanding of the molecular basis of RCC has facilitated the development of novel and more selective therapeutic approaches. An important role in RCC oncogenesis is played by the receptor for HGF, Met, which has attracted considerable attention, more recently as a molecular target for cancer therapy, and several drugs selectively targeting this pathway are now in clinical trials. This review will focus on efforts to understand the role of the Met signaling pathway in renal cancer and how this has contributed to the development of potent and selective drug candidates.

The renal cell carcinoma-associated oncogenic fusion protein PRCCTFE3 provokes p21 WAF1/CIP1-mediated cell cycle delay

Previously, we found that in t(X;1)(p11;q21)-positive renal cell carcinomas the bHLH-LZ transcription factor TFE3 is fused to a novel protein designated PRCC. In addition, we found that the PRCCTFE3 fusion protein, which has retained all known functional domains of TFE3, acts as a more potent transcriptional activator than wild type TFE3. We also found that PRCCTFE3 expression confers in vitro and in vivo transformation onto various cell types, including those of the kidney. Here we show that de novo expression of the PRCCTFE3 fusion protein provokes cell cycle delay. This delay, which is mediated by induction of the cyclin-dependent kinase inhibitor p21((WAF1/CIP1)), affects both the G1/S and the G2/M phases of the cell cycle and prevents the cells from undergoing polyploidization. We also show that the PRCCTFE3 fusion protein binds directly to the p21((WAF1/CIP1)) promoter and that the PRCCTFE3-induced up-regulation of p21((WAF1/CIP1)) leads to activation of the pRB pathway. Finally, we show that in t(X;1)(p11;q21)-positive renal tumor cells several processes that link PRCCTFE3 expression to p21((WAF1/CIP1))-mediated cell cycle delay are abrogated. Our data suggest a scenario in which, during the course of renal cell carcinoma development, an initial PRCCTFE3-induced cell cycle delay must be numbed, thus permitting continued proliferation and progression towards full-blown malignancy.