Gemcitabine-Induced Autophagy Protects Human Lung Cancer Cells from Apoptotic Death.
Gemcitabine has been used as a therapeutic drug combined with cisplatin for the treatment of lung cancer patients. However, the prognosis is poor due to acquired resistance. Accumulating studies have revealed that autophagy may contribute to the drug resistance. Therefore, the present study is aimed to clarify the mechanisms underlying gemcitabine-acquired resistance.



SPC-A1 and A549 cells were incubated with gemcitabine followed by assessment of cell viability with MTT assays. GFP-LC3 transient transfection, MDC staining, and transmission electron microscopy were used to detect the change of autophagy at morphological level. Flow cytometry was used to monitor the effect of 3-MA on gemcitabine-induced apoptosis. Western blot analysis was used to detect the expression of p62, LC3, Beclin-1, ATG5, activated caspase 3, Bax, BNIP3, BNIP3L, and Bcl-2.



Our study showed that gemcitabine significantly induced both autophagy and apoptosis in human lung cancer cells SPC-A1 and A549. Of interest was that when autophagy was inhibited by 3-MA, the gemcitabine-induced apoptosis was effectively enhanced, suggesting that gemcitabine can activate autophagy to impair the chemosensitivity of lung cancer cells. Furthermore, the inhibition of autophagy by 3-MA further increased the expression of activated caspase 3, Bax, BNIP3, and BNIP3L, all are critical apoptotic mediators. Contrarily, 3-MA treatment further decreased the expression of Bcl-2, which is an important anti-apoptotic protein.



Our study indicated that autophagy protected human lung cancer cells from gemcitabine-induced apoptosis, and the combined use of gemcitabine and an autophagic inhibitor in lung cancer patients may be an effective therapeutic strategy.
Anhui Geriatric Institute, the First Affiliated Hospital of Anhui Medical University, Jixi Road 218, Hefei, Anhui, 230022, People's Republic of China.
Hui-Mei
HM
Wu
Anhui Geriatric Institute, the First Affiliated Hospital of Anhui Medical University, Jixi Road 218, Hefei, Anhui, 230022, People's Republic of China.
Li-Jie
LJ
Shao
Anhui Geriatric Institute, the First Affiliated Hospital of Anhui Medical University, Jixi Road 218, Hefei, Anhui, 230022, People's Republic of China.
Zi-Feng
ZF
Jiang
Anhui Geriatric Institute, the First Affiliated Hospital of Anhui Medical University, Jixi Road 218, Hefei, Anhui, 230022, People's Republic of China. rongyuliu@hotmail.com.
Rong-Yu
RY
Liu
D000072283:A549 Cells; D000225:Adenine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D001343:Autophagy / Q000187:drug effects*; D000071187:Autophagy-Related Protein 5 / Q000378:metabolism; D000071186:Beclin-1 / Q000378:metabolism; D053148:Caspase 3 / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism; D000093542:Gemcitabine
C502778:ATG5 protein, human; D000964:Antimetabolites, Antineoplastic; D000071187:Autophagy-Related Protein 5; C494826:BAX protein, human; C090121:BNIP3 protein, human; C116838:BNIP3L protein, human; D000071186:Beclin-1; C477012:MAP1LC3A protein, human; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016271:Proto-Oncogene Proteins c-myc; D025521:Tumor Suppressor Proteins; D051028:bcl-2-Associated X Protein; D003841:Deoxycytidine; C025946:3-methyladenine; D053148:Caspase 3; D000225:Adenine; D000093542:Gemcitabine
Apoptosis; Autophagy; Chemoresistance; Gemcitabine; Lung cancer