Focal adhesion kinase regulates the phosphorylation protein tyrosine phosphatase-α at Tyr789 in breast cancer cells.

Protein tyrosine phosphatase (PTP)­α regulates the phosphorylation of focal adhesion kinase (FAK), which is important in cellular signal transduction and integration of proteins. It has been demonstrated that a FAK­Del33 mutation (deletion of exon 33; KF437463) in breast cancer tissues regulates cell migration through FAK/Src signaling activation. However, the detailed pathway for Src activation with FAK­Del33 remains to be elucidated. The present study used a retroviral expression system to examine changes in PTPα phosphorylation affected by the FAK­Del33 protein in breast cancer cells. Small interfering (si)RNA targeting PTPα interfered with the phosphorylation of Src. Wound­healing and migration assays were performed to identify cell morphology and quantitative analysis was performed by examining band color depth in western blot analysis. Significant differences were observed in the phosphorylation level of PTPα at Tyr789 between the FAK­Del33 and the wild­type breast cancer cells, suggesting that FAK regulated the phosphorylation level of PTPα at Tyr789 in breast cancer mutant FAK­Del33 cells. The gene expression profile with FAK siRNA did not alter the levels of phosphorylation in other mutants, including autophosphorylation disability (Y397F), ATP kinase dominant negative (K454R) and protein 4.1, ezrin, radixin, moesin domain attenuate (Δ375). FAK RNAi inhibited the activity of the FAK­Del33 at the Src site and rescued the elevated cell migration and invasion. The present study demonstrated for the first time, to the best of our knowledge, an increase in the phosphorylation level of PTPα­Tyr789 by its upstream activator, FAK­Del33, leading to Src activation in certain breast cancer cells, which has significant implications for metastatic potential.

Somatic mutational analysis of FAK in breast cancer: a novel gain-of-function mutation due to deletion of exon 33.

Focal adhesion kinase (FAK) regulates cell adhesion, migration, proliferation, and survival. We identified a novel splicing mutant, FAK-Del33 (exon 33 deletion, KF437463), in both breast and thyroid cancers through colony sequencing. Considering the low proportion of mutant transcripts in samples, this mutation was detected by TaqMan-MGB probes based qPCR. In total, three in 21 paired breast tissues were identified with the FAK-Del33 mutation, and no mutations were found in the corresponding normal tissues. When introduced into a breast cell line through lentivirus infection, FAK-Del33 regulated cell motility and migration based on a wound healing assay. We demonstrated that the expression of Tyr397 (main auto-phosphorylation of FAK) was strongly increased in FAK-Del33 overexpressed breast tumor cells compared to wild-type following FAK/Src RTK signaling activation. These results suggest a novel and unique role of the FAK-Del33 mutation in FAK/Src signaling in breast cancer with significant implications for metastatic potential.

Rab5a overexpression promoting ovarian cancer cell proliferation may be associated with APPL1-related epidermal growth factor signaling pathway.

Rab5a is a regulatory guanosine triphosphatase that is associated with the transport and fusion of endocytic vesicles, and participates in regulation of intracellular signaling pathways embraced by cells to adapt to the specific environment. Rab5a is also correlated with lung, stomach, and hepatocellular carcinomas. Here, we detected Rab5a in paraffin-embedded samples of 20 ovarian cysts, 20 benign cystadenomas, and 39 ovarian cancers by immunohistochemistry, and observed that Rab5a expression was significantly higher in ovarian cancer (P = 0.0001). By setting up stable HO-8910 cell lines expressing Rab5a or dominant negative Rab5a (Rab5a:S34N), we found that Rab5a overexpression enhanced the cell growth by promoting G1 into S phase. In contrast, Rab5a:S34N inhibited this process. Additionally, APPL1 (adaptor protein containing PH domain, PTB domain, and Leucine zipper motif), a downstream effector of Rab5a, was also involved in promoting HO-8910 cell cycle progress. But this function was blocked by Rab5a:S34N. Laser scanning confocal microscopy represented the colocalization of APPL1 and Rab5a in the plasmolemma, which changed with the time of epidermal growth factor (EGF) stimulation. We also found APPL1 could transfer from the membranes into the nucleus where it interacted with NuRD/MeCP1 (the nucleosome remodeling and histone deacetylase multiprotein complex). NuRD is reported to be involved in the deacetylation of histone H3 and H4 to regulate nuclear transcription. So Rab5a promoted proliferation of ovarian cancer cells, which may be associated with the APPL1-related epidermal growth factor signaling pathway.

Does testosterone prevent early postoperative complications after gastrointestinal surgery?

AIM: To investigate the role of sex hormones in the early postoperative complications of gastrointestinal diseases. METHODS: A total of 65 patients who underwent operations for gastric and colorectal diseases (mainly malignant diseases) were included in the study. Peripheral venous blood samples were collected at different times for analysis of estradiol, testosterone and progesterone. The only study endpoint was analysis of postoperative complications. RESULTS: Patients of both sexes were uniform but postoperative complication rate was significantly higher in female patients (P = 0.027). There was no significant association of estradiol and progesterone with postoperative complications. Testosterone levels in complicated patients were significantly lower than in uncomplicated patients (P < 0.05). Area under the receiver operating characteristic curve showed that a lower value of testosterone was a predictor for higher complication rate (P < 0.05), and a lower value of testosterone at later times after surgery was a better predictor of complications. CONCLUSION: Patients with low testosterone level were prone to higher postoperative complications, which was evident in both sexes. However, further studies are necessary to support this result.

Incidence of cytomegalovirus infection in Shanghai, China.

A city-wide cytomegalovirus serosurvey was conducted in Shanghai, China, and associated parameters were calculated by employing the catalytic model. The lowest seroprevalence was 60.37%, found in the >1- to 3-year age group. The value increased rapidly with age until 25 years, when a value of 97.03% was found, caused by the high force of infection (12.69) and by the reproductive rate (8.89).

Polymorphism of the D4Z4 locus associated with facioscapulohumeral muscular dystrophy 1A in Shanghai population.

OBJECTIVE: To investigate the D4Z4 repeats on chromosome 4q35 in normal individuals in Shanghai and analysis the polymorphism of the D4Z4 locus. METHODS: The length of D4Z4 repeats on chromosome 4q35 in 191 normal individuals in Shanghai was determined by pulsed-field gel electrophoresis and Southern blotting after double digestion with Eco RI and Bln I. The number of short D4Z4 repeats was counted after partial digestion with Kpn I. RESULTS: Among 191 normal individuals in Shanghai, seventeen showed the size of D4Z4 fragments ranged from 22 to 34 kb, i.e. 8.9% of individuals had fewer numbers of D4Z4 repeats. Of these 17 individuals, sixteen showed the short D4Z4 fragment on chromosome 4q35, and one low D4Z4 fragment was correlated to 4q35--> 10q26 translocation. CONCLUSION: The frequency of individuals having fewer numbers of D4Z4 repeats on chromosome 4q35 in Shanghai population is higher than that in Caucasian population although the short D4Z4 fragment on chromosome 4q35 is associated with facioscapulohumeral muscular dystrophy. These findings suggest that other factors may also contribute to facioscapulohumeral muscular dystrophy.

[Mitochondrial DNA mutation analysis in patients with mitochondrial myopathy].

OBJECTIVE: To examine mitochondrial DNA mutations in mitochondrial myopathy. METHODS: Three suspected cases of mitochondrial myopathy were examined by HE staining, histochemical staining methods and electron microscopy. The mutations in all 22 tRNA genes of mitochondrial genome were screened by polymerase chain reaction-single strand conformation polymorphism and DNA sequencing. RESULTS: The three cases were diagnosed as mitochondrial myopathy. The examinations revealed that patient 1 had a homoplasmic A1627G mutation in tRNA-Val gene, and patient 2 had a heteroplasmic A1627G/A mutation in tRNA-Val gene, and patient 3 had two mutationsuone was homoplasmic T5554C mutation in tRNA-Trp gene, the other was heteroplasmic A10412C/A mutation in tRNA-Arg gene. CONCLUSION: tRNA genes mutations of mtDNA might be one of the etiologies of mitochondrial myopathy.

Looking under every rock: Duchenne muscular dystrophy and traditional Chinese medicine.

Traditional Chinese medicine has been advocated to alleviate symptoms in Duchenne muscular dystrophy. To investigate this hypothesis, a pilot study was carried out in Beijing on 10 DMD boys treated with various regimens, including pills, decoctions, massages and acupuncture at various stages of their disease course. Despite the limited scientific impact of such a study, it seems as if the benefit, if any, is minimal. Moreover, some indirect clinical clues such as the cushingoid appearance found in a few patients suggest these drugs may also contain corticosteroids to some extent.