Polymerase chain reaction is a widely used technique to amplify particular sections of DNA for detecting the presence or absence of a gene. In this case the gene of interest is the HPV18 E6 gene. Human papilloma virus (HPV) is the most common viral infection of the reproductive tract (Cancer Research UK, 2016). More than 100 types of HPV has been identified but the two most common subtypes known to cause 70% of cervical cancer cases is subtype 16 and 18 (National Cancer Institute, 2015). The genes responsible for the replication of HPV in an infected person is the E6 and E7gene (Graham, 2010). E6 induces cell proliferation by stimulating degradation of tumour suppressor, p53, disturbing normal cell cycle leading to increased tumour cell growth (Yim and Park, 2005). However, there is a hypothesis that the drug arsenic trioxide (ATO) can kill cancerous cell by down regulating the E6 gene.
ATO is an arsenic based drug which has been used as an effective chemotherapeutic agents shown to induce apoptosis in several tumour cell line (Stevens et al., 2017). Recently ATO has been found to be very potent in anti leukaemic efficacy, especially for acute promyelotic leukaemia (APL) (Yedjou et al., 2010) and further research are being carried out to find out if ATO can be an effective treatment for other types of cancers.
The aim for this experiment is to use PCR to amplify HPV18 E6 gene to evaluate expression levels to detect if the drug ATO can down regulate E6. The cell line used in this experiment is the HeLa cell line derived from the malignant human cervical carcinoma which expresses E6 and E7 proteins from HPV18 DNA (Goodwin and DiMaio, 2000). As a control for the experiment the housekeeping gene Glyceraldehyde 3-phosphate dehydrogenase (GAP-DH) was used which is a common housekeeping gene used for internal control in experiment expression studies (Barber et al., 2005).