Investigation of the relationships of the sall4 gene with resistance genes in head and neck cancer cells

Sal-like protein 4 (SALL4) is a transcription factor found in embryonic stem cells, but it has been shown to be overexpressed in cancer cells, including head and neck squamous cell carcinomas (HNSCC), and is associated with cancer development, progression, and metastasis. Therefore, this thesis study aimed to elucidate the effects of the SALL4 gene on drug resistance development or resistance-developed cells in HNSCC. In our study, FaDU cells were used in normal and drug-resistant forms, and experiments were conducted on 6 groups, namely positive control group, inhibition group, PTX-applied group, both inhibition and drug-applied group, and negative control group. SALL4 inhibition in both normal and drug-resistant cells was checked with real-time polymerase chain reaction (qRT-PCR) and Western Blot (WB), and then the relationship between the SALL4 gene and resistance genes was detailed with molecular genetic analyses. Then, cell cycle, cell migration, and apoptotic status were examined in cell lines. The analysis results showed that SALL4 was successfully inhibited in both cell lines, and that SALL4 suppression strengthened the apoptosis-increasing effect of PTX; had an antiproliferative effect on the cell cycle, and created a synergistic effect when applied together with PTX, especially in resistant cells. It is thought that the findings obtained may help develop new therapeutic strategies in HNSCC and help patients respond better to treatment.