Research progress in the role of FBXW7 in drug resistance against non-small cell lung cancer / 中南大学学报(医学版)

Non-small cell lung cancer (NSCLC) is one of the most common malignant tumors in the world. NSCLC shows serious effect on prognosis for drug resistance, and it is necessary to study the molecular mechanism for drug resistance in NSCLC. Ubiquitin-proteasome system (UPS) can regulate some important cellular processes by degrading short-term protein, and the abnormal expression is closely related to the occurrence, development and prognosis of tumor. The F-box family protein is an important component of the ubiquitin proteasome, such as cycle regulation, transcriptional regulation, signal transduction, apoptosis and differentiation. F-box and WD-40 domain protein 7 (FBXW7) is just the classic protein components among F-box family protein. Studies have shown that FBXW7 is related to drug resistance in NSCLC. The main mechanism is that FBXW7 mutation leads to drug resistance by reducing ubiquitination and degradation of its downstream proteins, including Snail protein, myeloid cell leukemia sequence 1 (MCL-1), mammalian target of rapamycin (mTOR), and coiled-coil-domain containing 6 (CCDC6). Rapamycin, histone deacetylase inhibitor MS-275, and rabdosia are effective in drug-resistant NSCLC patients with FBXW7 mutation.

Expression of FBXW7 in esophageal squamous cell carcinoma and its clinical significance / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To evaluate the expression of FBXW7 in esophageal squamous cell carcinoma (ESCC) and to explore the correlation of FBXW7 expression with clinicopathologic features and prognosis of ESCC.</p><p><b>METHODS</b>Ninety cases of ESCC and twenty cases of tumor-adjacent normal tissues and forty intraepithelial neoplasia tissues were detected by immunohistochemistry methods. The expression of FBXW7 in 40 surgical ESCC tissues and tumor-adjacent normal tissues was detected by Western blotting and RT-PCR. The relationship between the expression of FBXW7, clinicopathological characteristics and prognosis was analyzed.</p><p><b>RESULTS</b>The positive rate of FBXW7 protein was significantly lower in the ESCC and high-grade intraepithelial neoplasia tissues than in the tumor-adjacent normal tissues and low grade intraepithelial neoplasia tissues (40.0% and 33.3% vs. 85.0% and 77.3%, χ² = 21.923, P < 0.001). The FBXW7 protein was down-regulated in ESCC tissues (P < 0.05), whereas the FBXW7 mRNA was down-regulated in ESCC tissues compared with that in the paracancerous tissues. The expression of FBXW7 was significantly correlated with TNM stage, degree of differentiation, invasion depth and lymph node metastasis (χ² =9.643, 14.908, 16.294, 10.222, respectively, P = 0.002, 0.001, 0.000, 0.001). In the ninety patients, the 5-year survival rates of cases with positive and negative expression of FBXW7 protein was 67.6% and 39.3%, respectively (χ² =6.699, P = 0.01).</p><p><b>CONCLUSIONS</b>The results of this study demonstrate that FBXW7 expression is significantly declined in ESCC and high grade intraepithelial neoplasia tissues, and is closely correlated with poor prognosis of this disease. FBXW7 as a tumor suppressor gene may play an important role in the carcinogenesis, development and metastasis of ESCC. These results suggest that FBXW7 may become a valuable marker for the severity and prognosis in ESCC.</p>

Mutations of FBXW7 in Adult T-Cell Acute Lymphocytic Leukemia / 中国实验血液学杂志

<p><b>BACKGROUD</b>F-Box and WD40 domain containing protein 7 gene (FBXW7) is part of the E3 ubiquitin ligase complex that controls the turnover of various proteins including NOTCH1, c-MYC and Cyclin E.</p><p><b>OBJECTIVE</b>To investigate the mutations of FBXW7 gene in adult T-cell acute lymphoblastic leukemia (T-ALL).</p><p><b>METHODS</b>Exon 5-12 of FBXW7 were amplified, cloned and sequenced in 54 adult T-ALL patients; the frequency, position and types of FBXW7 mutation were analyzed; the co-existing of mutations with NOTCH1 and their relevant prognostic significance were explored as well.</p><p><b>RESULTS</b>FBXW7 mutations were identified in 11.1% of adult T-ALL patients. A total of 4 types of point mutations (R465H, R465L, R479P and R505C) and 1 deletion/insertion mutation were observed, and all of them located in WD40 domain of FBXW7. In addition, co-existing mutations with NOTCH1 were identified in 83.3% of patients with FBXW7 mutation. Notably, the co-existed NOTCH1 mutations, including 3 point mutations (L1574P, L1596H and L1600P) and 2 deletion/insertion mutations located in HD domain. Furthermore, patients with FBXW7 mutation only had significantly longer overall survival compared with those without mutation (P=0.049).</p><p><b>CONCLUSION</b>FBXW7 mutations may play an important role in NOTCH1 mediated pathogenesis in T-ALL.</p>