Overexpression of Septin1 in Oral Carcinoma

Objectives: Our previous study using proteomic profiling demonstrated significant up-regulation of Septin1, a conserved family of GTPase proteins, in oral squamous-cell carcinoma (OSCC)-derived cell lines. The aim of the current study was to determine the potential involvement of Septin1 in OSCC-derived cell lines, oral premalignant lesions (OPLs), and primary OSCCs.

Methods: Tissue samples from 85 unrelated Japanese patients with primary SCC of the oral cavity and from 33 unrelated Japanene with OPL of the oral cavity. The OSCC-derived cell lines used in this study were HSC-2, HSC-3, HSC-4, HO-1-n-1, OK92 and KON. We evaluated the status of Septin1 mRNA and protein expression in OSCC-derived cell lines, OPLs and primary OSCCs by real-time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR), Western blot analysis, and immunohistochemistry.

Results: A significant (P<0.05) increase in Septin1 expression was evident in all OSCC-derived cell lines examined compared to human normal oral keratinocytes (HNOKs) and OPLs. In immunohistochemistry, while the vast majority of the OSCCs (89%) were positive for Septin1, no immunoreaction was observed in corresponding normal tissues and OPLs. In addition, qRT-PCR data were consistent with the protein expression status.

Conclusion: Septin1 expression could contribute to cancer progression, proliferation, or both, and that Septin1 may be a potential diagnostic marker of highly active cancer and a therapeutic target for OSCCs.