Knockdown of POLA2 increases gemcitabine resistance in lung cancer cells.
Gemcitabine is used as a standard drug treatment for non-small cell lung cancer (NSCLC), but treatment responses vary among patients. Our previous studies demonstrated that POLA2 + 1747 GG/GA single nucleotide polymorphism (SNP) improves differential survivability and mortality in NSCLC patients. Here, we determined the association between POLA2 and gemcitabine treatment in human lung cancer cells.



Human PC9, H1299 and H1650 lung cancer cell lines were treated with 0.01-100 μM gemcitabine for 72 h. Although all 3 cell lines showed decreased cell viability upon gemcitabine treatment, H1299 was found to be the most sensitive to gemcitabine treatment. Next, sequencing was performed to determine if POLA2 + 1747 SNP might be involved in gemcitabine sensitivity. Data revealed that all 3 cell lines harbored the wild-type POLA2 + 1747 GG SNP, indicating that the POLA2 + 1747 SNP might not be responsible for gemcitabine sensitivity in the cell lines studied. Silencing of POLA2 gene in H1299 was then carried out by siRNA transfection, followed by gemcitabine treatment to determine the effect of POLA2 knockdown on chemosensitivity to gemcitabine. Results showed that H1299 exhibited increased resistance to gemcitabine after POLA2 knockdown, suggesting that POLA2 does not act alone and may cooperate with other interacting partners to cause gemcitabine resistance.



Collectively, our findings showed that knockdown of POLA2 increases gemcitabine resistance in human lung cancer cells. We propose that POLA2 may play a role in gemcitabine sensitivity and can be used as a prognostic biomarker of patient outcome in NSCLC pathogenesis.
National University Cancer Institute Singapore, National University Health System, Singapore, Singapore.
Vivien
V
Koh
Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore.
Hsueh Yin
HY
Kwan
National University Cancer Institute Singapore, National University Health System, Singapore, Singapore.
Woei Loon
WL
Tan
Institute for Infocomm Research, Agency for Science, Technology and Research, Singapore, Singapore. tlmah@i2r.a-star.edu.sg.
Tzia Liang
TL
Mah
National University Cancer Institute Singapore, National University Health System, Singapore, Singapore. Wei_Peng_YONG@nuhs.edu.sg.|Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore. Wei_Peng_YONG@nuhs.edu.sg.
Wei Peng
WP
Yong
D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002874:Chromosome Mapping; D019295:Computational Biology / Q000379:methods; D004256:DNA Polymerase I / Q000235:genetics*; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D004843:Epistasis, Genetic; D015972:Gene Expression Regulation, Neoplastic; D055785:Gene Knockdown Techniques; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D000093542:Gemcitabine
D000964:Antimetabolites, Antineoplastic; D003841:Deoxycytidine; D004256:DNA Polymerase I; D000093542:Gemcitabine
Drug response; Gemcitabine; Non-small cell lung cancer; POLA2; Single nucleotide polymorphism