2. Academic Validation
  3. Modulation of anti-cancer drug sensitivity through the regulation of mitochondrial activity by adenylate kinase 4

Modulation of anti-cancer drug sensitivity through the regulation of mitochondrial activity by adenylate kinase 4

  • J Exp Clin Cancer Res. 2016 Mar 16;35:48. doi: 10.1186/s13046-016-0322-2.
Koichi Fujisawa 1 2,  Shuji Terai 3 4,  Taro Takami 2,  Naoki Yamamoto 2,  Takahiro Yamasaki 2 5,  Toshihiko Matsumoto 2 5,  Kazuhito Yamaguchi 6,  Yuji Owada 6,  Hiroshi Nishina 7,  Takafumi Noma 8,  Isao Sakaida 1 2
Affiliations

Affiliations

  • 1 Center for Regenerative Medicine, School of Medicine, Yamaguchi University, Ube, Japan.
  • 2 Department of Gastroenterology and Hepatology, School of Medicine, Yamaguchi University, Ube, Japan.
  • 3 Department of Gastroenterology and Hepatology, School of Medicine, Yamaguchi University, Ube, Japan. terais@med.niigata-u.ac.jp.
  • 4 Division of Gastroenterology and Hepatology, School of Medical and Dental Sciences, Niigata University, 1-757 Asahimachidori, Chuo-Ku, Niigata, 951-8510, Japan. terais@med.niigata-u.ac.jp.
  • 5 Department of Oncology and Laboratory Medicine, School of Medicine, Yamaguchi University, Ube, Japan.
  • 6 Department of Organ Anatomy, School of Medicine, Yamaguchi University, Ube, Japan.
  • 7 Department of Developmental and Regenerative Biology, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan.
  • 8 Department of Molecular Biology, Institute of Biomedical Sciences, Tokushima University School, Tokushima, Japan.
PMID: 26980435 DOI: 10.1186/s13046-016-0322-2
Abstract

Background: Adenylate kinase is a key Enzyme in the high-energy phosphoryl transfer reaction in living cells. An isoform of this Enzyme, adenylate kinase 4 (AK4), is localized in the mitochondrial matrix and is believed to be involved in stress, drug resistance, malignant transformation in Cancer, and ATP regulation. However, the molecular basis for the AK4 functions remained to be determined.

Methods: HeLa cells were transiently transfected with an AK4 small interfering RNA (siRNA), an AK4 short hairpin RNA (shRNA) plasmid, a control shRNA plasmid, an AK4 expression vector, and a control expression vector to examine the effect of the AK4 expression on cell proliferation, sensitivity to anti-cancer drug, metabolome, gene expression, and mitochondrial activity.

Results: AK4 knockdown cells treated with short hairpin RNA increased ATP production and showed greater sensitivity to hypoxia and anti-cancer drug, cis-diamminedichloro-platinum (II) (CDDP). Subcutaneous grafting AK4 knockdown cells into nude mice revealed that the grafted cells exhibited both slower proliferation and reduced the tumor sizes in response to CDDP. AK4 knockdown cell showed a increased oxygen consumption rate with FCCP treatment, while AK4 overexpression lowered it. Metabolome analysis showed the increased levels of the tricarboxylic acid cycle intermediates, fumarate and malate in AK4 knockdown cells, while AK4 overexpression lowered them. Electron microscopy detected the increased mitochondrial numbers in AK4 knockdown cells. Microarray analysis detected the increased gene expression of two key Enzymes in TCA cycle, Succinate Dehydrogenase A (SDHA) and oxoglutarate dehydrogenease L (OGDHL), which are components of SDH complex and OGDH complex, supporting the metabolomic results.

Conclusions: We found that AK4 was involved in hypoxia tolerance, resistance to anti-tumor drug, and the regulation of mitochondrial activity. These findings provide a new potential target for efficient Anticancer therapies by controlling AK4 expression.

Keywords

Adenylate kinase; Drug resistance; Energy metabolism; Flux analysis; Hypoxia; Metabolome; Mitochondria.

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