Expression of cyclin B1, D1 and K in non-small cell lung cancer H1299 cells following treatment with sulforaphane

Sulforaphane (SFN) was first isolated from broccoli sprout and it is present at high concentrations in plants belonging to the Cruciferae family. The chemotherapeutic and anti-cancerogenic capacities of SFN have been demonstrated by inhibition of cancer cell proliferation in several cancer cell lines. The aim of the present study was to evaluate the effect of SFN on apoptosis, cell cycle and expression of selected cell cycle-associated proteins: Cyclin B1, cyclin D1 and cyclin K in the H1299 cell line. The non-small cell lung cancer cell line H1299 was treated with increasing concentrations of SFN (5, 10 and 15 mu M) for two days. After incubation, the percentage of cells in the individual cell cycle phases, as well as the percentage of necrotic and apoptotic cells, were estimated using flow cytometry. The expression of cyclins was examined by immunofluorescence staining, flow cytometry, western blot analysis and qRT-PCR. Cyclin K was characterized by nuclear localization and increased expression after treatment with SFN. The expression data were confirmed by qRT-PCR. SFN-induced cell cycle arrest was associated with a decrease in cyclin B1 expression. Cells treated with SFN were also characterized by higher cyclin D1 and cyclin K expression. These data suggest the involvement of cyclin K in response to SFN. Moreover, we investigated the prognostic value of cyclin K, CDK12 and CDK13 in adenocarcinoma patients using The Kaplan-Meier plotter' (KM plotter) database. It was shown that high expression of CDK12 and CDK13 but no cyclin K proteins is associated with worse overall survival among adenocarcinoma patients.