Drp1 regulates mitochondrial morphology and cell proliferation in cutaneous squamous cell carcinoma

J Dermatol Sci. 2017 Dec;88(3):298-307. doi: 10.1016/j.jdermsci.2017.08.004. Epub 2017 Aug 5.


Background: Dynamin-related protein 1 (Drp1) mediates mitochondrial fission. Recently, several studies have shown that Drp1 plays an important role in some cancers. However, little is known about Drp1 in cutaneous squamous cell carcinoma (SCC).

Objective: To investigate the role of Drp1 in the tumorigenesis of cutaneous SCCs.

Methods and results: We investigated cell proliferation, cell cycle, mitochondrial morphology, and MAPK signaling pathway using cutaneous SCC A431 and DJM1 cells that were transfected with shRNA vectors targeting Drp1. The Drp1 gene-knockdown SCC cells showed lower cell proliferation than scramble-control cells, as assessed by direct cell counting and clonogenic assays. DNA content analysis showed Drp1 knockdown to cause G2/M arrest. Morphologically, the depletion of Drp1 resulted in an elongated, hyper-fused mitochondrial network. The MEK inhibitor PD325901 suppressed cell proliferation, as well as inhibiting the phosphorylation of ERK1/2 and Drp1Ser616. Also, PD325901 caused the dysregulation of the mitochondrial network. In tumor xenografts of DJM1 cells, the knockdown of Drp1 suppressed tumor growth in vivo, and clinically, the expression levels of Drp1 were higher in cutaneous SCCs than in normal epidermis, and correlated positively with the advanced clinical stages.

Conclusion: Our results reveal a crucial function for Drp1 in regulating tumor growth, mitochondrial morphology, and cell cycle in cutaneous SCC, suggesting that Drp1 could be a novel target for skin tumor therapies.

Keywords: Cell cycle; Drp1; MAPK; Proliferation; Squamous cell carcinoma.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Animals
  • Benzamides / pharmacology
  • Carcinogenesis / pathology
  • Carcinoma, Squamous Cell / pathology*
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Cell Proliferation / physiology*
  • Diphenylamine / analogs & derivatives
  • Diphenylamine / pharmacology
  • Dynamins
  • Female
  • G2 Phase Cell Cycle Checkpoints
  • GTP Phosphohydrolases / antagonists & inhibitors
  • GTP Phosphohydrolases / genetics
  • GTP Phosphohydrolases / metabolism*
  • Gene Knockdown Techniques
  • Humans
  • MAP Kinase Signaling System
  • Male
  • Mice
  • Mice, Inbred BALB C
  • Mice, Nude
  • Microtubule-Associated Proteins / antagonists & inhibitors
  • Microtubule-Associated Proteins / genetics
  • Microtubule-Associated Proteins / metabolism*
  • Middle Aged
  • Mitochondria / physiology*
  • Mitochondrial Dynamics / drug effects
  • Mitochondrial Dynamics / physiology
  • Mitochondrial Proteins / antagonists & inhibitors
  • Mitochondrial Proteins / genetics
  • Mitochondrial Proteins / metabolism*
  • Neoplasm Staging
  • Phosphorylation / drug effects
  • Quinazolinones / pharmacology
  • RNA Interference
  • RNA, Small Interfering / metabolism
  • Skin Neoplasms / pathology*
  • Xenograft Model Antitumor Assays


  • 3-(2,4-dichloro-5-methoxyphenyl)-2-sulfanyl-4(3H)-quinazolinone
  • Benzamides
  • Microtubule-Associated Proteins
  • Mitochondrial Proteins
  • Quinazolinones
  • RNA, Small Interfering
  • mirdametinib
  • Diphenylamine
  • GTP Phosphohydrolases
  • DNM1L protein, human
  • Dynamins