CCND1 and infection: We observed that Cyclin D1 protein levels decreased in both cell lines after 24 h of infection; however, for HIF-1α knockdown cells, Cyclin D1 levels were higher compared to control cells at this time point of infection (Figure 8A), suggesting that HIF-1α contributes to the decrease in Cyclin D1 triggered by H. pylori infection and cell cycle arrest.