Dual Switch in Lipid Metabolism in Cervical Epithelial Cells during Dysplasia Development Observed Using Raman Microscopy and Molecular Methods

Abstract

Simple Summary

Raman microscopy is an inexpensive and label-free method. The literature describes many attempts to use this method for cancer diagnosis. In this study, we used it to differentiate the lipid profile of cervical epithelial cells depending on the severity of pathological changes and the presence of HPVhr infection. Using molecular methods, we also determined the degree of methylation of the gene encoding the prolipidogenic protein SREBP1, as well as the number of copies of the mitochondrial genome in the tested samples. This multimethodological approach allowed not only to determine the differences between samples with different advancement of pathological changes, but also enabled to shed light on the molecular mechanism behind them, as well as gave hope for the possibility of using our approach for early detection of cervical dysplasia in the future.

Abstract

Cellular lipid metabolism is significantly transformed during oncogenesis. To assess how dysplasia development influences lipid cellular metabolisms and what is the molecular background behind it, cervical epithelial cells of 63 patients assigned to seven groups (based on the cytological examination and HPVhr test results) were studied using a multimethodological approach including Raman microscopy and molecular methods. The consistent picture obtained studying the lipid content, cell inflammation, SREBF1 gene methylation (hence SREBP1 inhibition) and level of mitochondrial DNA copies (indirectly the number of mitochondria) showed that changes in lipid metabolism were multidirectional. Cells from patients classified as mildly dysplastic (LSIL) exhibited a unique behavior (the highest level of inflammation and SREBF1 methylation, the lowest lipid content and mitochondrial DNA). On the contrary, cells from severe dysplastic (HSIL) and cancer (SCC) groups showed the opposite characteristics including the lowest SREBF1 gene methylation as well as the highest level of mitochondrial DNA and lipid cellular concentration (for HSIL/HPVhr+ and SCC groups). Following dysplastic progression, the lipid content decreases significantly (compared to the control) for mildly abnormal cells, but then increases for HSIL/HPVhr+ and SCC groups. This intriguing dual switch in lipid metabolism (reflected also in other studied parameters) on the way from normal to squamous carcinoma cells is of potential diagnostic interest.