Direct interaction between Rab5a and Rab4a enhanced epidermal growth factor-stimulated proliferation of gastric cancer cells.

BACKGROUND: Gastric cancer (GC) is one of the leading causes of cancer-related death worldwide. Although targeted therapies such as antibodies against human epidermal growth factor receptor 2 or vascular endothelial growth factor receptor 2 have been widely used in the treatment of metastatic cancer, the overall outcomes are poor. Therefore, elucidation of the mechanism underlying cancer progression is important to improve prognosis. Overexpression of the Rab5a gene has been confirmed to correlate with tumorigenesis of many cancers, but the mechanism underling, especially of GC, is still unclear. AIM: To investigate the effects of Rab5a overexpression on the tumorigenesis of GC. METHODS: First, the expression levels of Rab5a and Rab4a in primary tumorous tissues of GC patients diagnosed between 2015 and 2018 were analyzed. Then we constructed HGC-27 cell lines overexpressing green fluorescent protein-Rab5a or red fluorescent protein-Rab4a and investigated the interaction between Rab5a or Rab4a using Western blotting, co-immunoprecipitation, confocal microscopy, and colocalization analysis. Finally, epidermal growth factor-stimulated proliferation of these cell lines was analyzed using cell counting kit-8 cell viability assay. RESULTS: Compared with normal gastric tissues, the expression levels of Rab5a and Rab4a increased progressively both in paracancerous tissues and in advanced cancerous tissues. Epidermal growth factor could promote the proliferation of HGC-27 cells, especially Rab5a-overexpressing HGC-27 cells. Notably, Rab5a and Rab4a co-overexpression promoted the proliferation of HGC-27 cells to the greatest extent. Further analysis identified a direct interaction between Rab5a and Rab4a in HGC-27 cells. CONCLUSION: Co-overexpression of Rab5a and Rab4a in GC may promote the endosomal recycling of epidermal growth factor receptor, which in turn contributes to poor prognosis and tumor progression in GC patients. Inhibition of Rab5a or Rab4a expression might be a promising therapy for refractory GC.

Evaluation of the diagnostic performance of panfungal polymerase chain reaction assay in invasive fungal diseases.

Timely diagnosis of invasive fungal diseases (IFDs) is important, as delays in treatment initiation are associated with increased mortality rates. However, early diagnosis of IFDs in immunocompromised patients remains difficult. The conventional diagnostic methods currently used for IFDs are not sufficiently effective. Molecular tests, such as polymerase chain reaction (PCR)-based assays, have great potential to improve the early diagnosis of IFDs due to their sensitivity and specificity. In the present study, the diagnostic performance of panfungal PCR assays in IFD patients who received bone marrow transplantation was evaluated. The results suggested that panfungal PCR assay offered a quick and convenient guide for clinical decision-making by identifying higher numbers of fungal species in comparison with the conventional blood culture method. Furthermore, panfungal PCR assay exhibited a sensitivity of 93% and a specificity of 71% in the diagnosis of IFD patients based on the EORTC/MSG criteria. Thus, the present study concluded that the reported PCR-based method was effective and sensitive in early IFD diagnosis and should be integrated into clinical decision-making for the treatment of IFDs in the future.

[Recurrent deep vein thrombosis caused by heterozygous missense mutation of the protein S gene: genetic analysis of a case].

OBJECTIVE: To analyze the molecular pathogenesis of protein S deficiency in an adolescent case of recurrent deep vein thrombosis (DVT). METHODS: Blood samples from the patient and his family members were collected for detection of the coagulation parameters by one-step clotting method, and the protein S (PS) and protein C activities were measured by a chromogenic assay. Enzyme-linked immunosorbent assay was employed for detecting the levels of free PS antigen. All the exons and exon-intron boundaries of the patients PS gene were amplified using PCR and analyzed by direct sequencing. RESULTS: As carriers of hereditary PS deficiency, both the patient and his father showed a heterozygous C82792T point mutation in the 10th exon of their PS gene which resulted in the substitution of arginine314 by cysteine in the polypeptide chain of PS protein. CONCLUSION: Recurrence of DVT in this patient is the result of hereditary PS deficiency caused by a novel heterozygous missense mutation in the PS gene.

[Two novel mutations in one pedigree with hereditary Factor VII deficiency].

OBJECTIVE: To explore the mutations of coagulation factor VII (FVII) gene in one pedigree with hereditary FVII deficiency, and to investigate the molecular mechanisms of FVII deficiency. METHODS: FVII gene mutations were analysed in the pedigree by direct DNA sequencing. The mutated DNA fragments were cloned into pMD19-T simple TA vector, and sequenced to confirm their distribution on chromosome. The plasma activity of FVII of the probands and their family members was detected with coagulation assay. The antigen of FVII were identified with ELISA. RESULTS: Three gene mutations were detected in the pedigree: A/G to C at 15386 resulting in Arg353Pro/Gln353Pro, A to T at 15274 resulting in Lys316Stop, all three mutations were heterozygotes. Three kinds of polymorphisms were identified in his father: A to G transition at position 15386 resulting in Arg353Gln, heterozygotic deletion of 2050 - 2059 cctatatcct in promoter and G to A mutation in intron 1a, the same polymorphisms were found in his grandfather. The three polymorphisms were located in the same chromosome of his father. CONCLUSION: Two mutations were found in the pedigree with hereditary FVII deficiency. One is nonsense mutation (Lys316Stop), the other is missense one (Gln353Pro). Gln353Pro and Lys316Stop might be the molecular mechanisms of FVII deficiency. The two novel mutations were reported for the first time in the literature.