3.3. hPAF1C promotes cancer cell proliferation and colony formation, synergistically with c-MYC
In order to evaluate the impact of hPAF1C on cancer cell pro- liferation, we utilized siRNAs to knock-down hPAF1 expression using standard transfection protocols. The cell proliferation assays (Promega) were conducted and monitored over a time period of 7
days, revealing that inhibition of hPAF1C led to significantly slower cell proliferation (Fig. 4A) in 3 NSCLC cell lines (A549, H838, H1650) with high-level hPAF1 expression. While in clongenic survival as- says, we also observed that inhibition of hPAF1C induced a notable decrease by at least 30% (ranging to over 80%) in the capabilities of above 3 NSCLC cell lines to form colonies (Fig. 4B). Interestingly, further cell proliferation assays in NSCLC H838 cells showed that whereas cancer cell growth was partially inhibited with either hPAF1 siRNA or c-MYC siRNA treatment, it was completely sup- pressed with the co-treatment of both hPAF1 and c-MYC siRNAs, as illustrated in Fig. 4C.
Taken together, our results suggested that hPAF1C serves to promote NCSLC cell proliferation and clongenic survival through possible regulation of c-MYC, and both hPAF1C and c-MYC syner- gistically promote the growth of cancer cells.