Effects of Over-Expression of LOC92912 Gene on Cell Cycle Progression

Background: We had previously identified the genes involved in squamous cell carcinoma of the head and neck using differential display and DNA microarray techniques. We also reported the first analytical study on a novel human gene called LOC92912, which was identified by differential display as a gene up-regulated in such carcinomas. LOC92912, which is a putative member of the E2 ubiquitin conjugating enzyme family, is located on chromosome 15q and encodes a protein of 375 amino acids. In this study, we present the extended analysis of LOC92912 gene in order to uncover the pathway implicated in cancer development or progression. We established a series of RPMI 2650 cell line permanently over-expressing LOC92912 gene, together with their related controls. Methods: LOC92912 gene was cloned in pSG5-expressing vector. In vitro translation assay was performed using pSG5-expressing LOC92912. The construct was used for transient and permanent transfection of LOC92912 gene into RPMI 2650 cell line. Cell cycle analysis, clonogenicity, and cell growth assay for cells permanently over-expressing LOC92912 were performed. Focus-like formation studies, also, were investigated on cells permanently over-expressing LOC92912. Results: We found that RPMI 2650 cells permanently overexpressing LOC92912 show an increase in the number of cells accumulated in G0/ G1 phase of the cell cycle, a decrease in clonogenicity and cell growth and formation of focus-like structures. Preliminary data also showed changes in cell shape and cell-cell adhesion. Conclusion: Our results demonstrated that LOC92912 induced alterations in the proliferation of cells and might represent a putative novel regulator of cell cycle and some other cellular functions. This novel human gene may also represent a new target for treatment of cancers.