Overexpression of LAPTM4B promotes growth of gallbladder carcinoma cells in vitro.

Background: The overexpression of LAPTM4B-35 in gallbladder carcinoma (GBC) and its clinicopathologic and prognostic significance have been previously shown. Thus, this gene may play a role in the growth of GBC cells.

Methods: The pcDNA3-AE containing the complete open reading frame of LAPTM4B (lysosome-associated protein transmembrane-4beta) and mock (pcDNA3) plasmids were transiently transfected into GBC-SD cells. Cell proliferation, cell cycle distribution, and protein expression were evaluated by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium assay, flow cytometry, and Western blot, respectively.

Results: Cells transfected with pcDNA3-AE revealed accelerated proliferation, less serum dependence, and significant cell cycle progression compared with cells transfected with mock plasmid and parent cells. These phenotypes were accompanied by upregulated expression of C-myc, c-Fos, c-Jun, cyclin D1, and cyclin E and downregulated expression of P16 and P-27.

Conclusions: LAPTM4B overexpression promotes the growth of GBC cells in vitro by regulating the expression levels of some proliferation-associated proteins. Therefore, the LAPTM4B gene might be used as a novel therapeutic target of GBC.