High resolution analysis of the intracellular proteome of cervical cancer cell lines unveils novel regulators of cervical carcinogenesis.

ABSTRACT

Cervical cancer remains the fourth most common and most lethal type of cancer in women, despite the applied regular screening and prevention strategies, while the available treatment schemes still pose a threat to fertility. Substantial understanding of the underlying mechanisms and development of novel diagnostic, prognostic and therapeutic approaches are critical steps for improving cervical cancer management. Towards this goal, a comparative proteomic analysis was conducted between three cervical cancer cell lines (HeLa HPV18+, SiHa HPV16+, C33A HPV­) and normal cervical keratinocytes (HCK1T). The total cell extract of each cell line was analyzed by liquid chromatography coupled to tandem mass spectrometry (LC­MS/MS). Differential expression analysis revealed 919, 826 and 1,370 deregulated proteins in the comparisons of HeLa, SiHa and C33A with HCK1T cell lines, respectively. Pathway enrichment analysis of the differentially expressed proteins highlighted common cancer characteristics such as high metabolic demands and increased cell turnover, confirming the validity of the proteomic results. Extensive literature mining of the consistently differentially expressed proteins that resulted from the three comparisons was performed leading to a shortlist of 21 proteins that are potentially involved in cervical malignancy. The criteria for this shortlisting were the association of the proteins with various types of cancer, while there is no study as yet associating their expression to cervical cancer. Moreover, the expression trend of two of the shortlisted proteins was validated using western blot analysis. The proteomic datasets generated in this study can be utilized to enrich the current knowledge on cervical cancer pathology and unveil key molecular mechanisms of carcinogenesis. In conclusion, the shortlist of consistently deregulated proteins between cervical cancer cell lines and normal cervical keratinocytes can be used for validation in clinical samples and in functional investigation experiments that could ultimately lead to the discovery of novel disease biomarkers and drug targets.