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ATG5 knockout leads to malignant cell transformation and resistance to Src family kinase inhibitor PP2
Author(s) -
Lee Michael,
Hwang SungHee
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.775.5
Subject(s) - atg5 , autophagy , apoptosis , cancer cell , cancer research , microbiology and biotechnology , oncogene , chemistry , biology , cancer , cell cycle , biochemistry , genetics
We previously demonstrated that modulators of autophagy might be used beneficially as adjunctive therapeutic agents during the treatment of cancers with Src tyrosine kinase specific inhibitor PP2. Here, we investigated the role of autophagy in cell growth by using established ATG5 knockout (KO) cell line with CRISPR/Cas9 system. The conversion of non‐autophagic LC3‐I to autophagic LC3‐II and RT‐PCR confirmed the functional gene knockout. Interestingly, the growth of ATG5 KO cells was significantly enhanced compared to wild type (WT) cells. In particular, autophagy‐deficiency in NIH 3T3 cells enhanced susceptibility to cellular transformation as determined by an in vitro clonogenic survival assay and soft agar colony formation assay. Furthermore, ATG5 KO cells were more resistant to PP2 treatment than were WT cells. Additionally, the proportion of apoptotic cells significantly decreased when treated with PP2 in ATG5 KO cells compared with WT cells. Interestingly, we found that expression levels of p53 were much stronger in ATG5 KO cells, which showed lower apoptosis rates than did WT cells. ATG5 knockout is thought to be lead to a compensatory increase in p53 proteins due to a decreased apoptosis rate. We also found the marked up‐regulation of p‐ERK and p‐MEK in ATG5 KO cells, suggesting that the promotion of PP2 resistance by ATG5 knockout was associated with elevated levels of p‐MEK and p‐ERK. Taken together, our results suggest that autophagy deficiency can lead to malignant cell transformation and resistance to anti‐cancer therapy. Support or Funding InformationGrant Funding Source: Supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2016R1D1A1B03930193)