Critical role of SOX2-IGF2 signaling in aggressiveness of bladder cancer

Sci Rep. 2020 May 19;10(1):8261. doi: 10.1038/s41598-020-65006-z.

Abstract

Signaling elicited by the stem cell factors SOX2, OCT4, KLF4, and MYC not only mediates reprogramming of differentiated cells to pluripotency but has also been correlated with tumor malignancy. In this study, we found SOX2 expression signifies poor recurrence-free survival and correlates with advanced pathological grade in bladder cancer. SOX2 silencing attenuated bladder cancer cell growth, while its expression promoted cancer cell survival and proliferation. Under low-serum stress, SOX2 expression promoted AKT phosphorylation and bladder cancer cells' spheroid-forming capability. Furthermore, pharmacological inhibition of AKT phosphorylation, using MK2206, inhibited the SOX2-mediated spheroid formation of bladder cancer cells. Gene expression profiling showed that SOX2 expression, in turn, induced IGF2 expression, while SOX2 silencing inhibited IGF2 expression. Moreover, knocking down IGF2 and IGF1R diminished bladder cancer cell growth. Lastly, pharmacological inhibition of IGF1R, using linsitinib, also inhibited the SOX2-mediated spheroid formation of bladder cancer cells under low-serum stress. Our findings indicate the SOX2-IGF2 signaling affects the aggressiveness of bladder cancer cell growth. This signaling could be a promising biomarker and therapeutic target for bladder cancer intervention.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Humans
  • Insulin-Like Growth Factor II / genetics
  • Insulin-Like Growth Factor II / metabolism*
  • Kruppel-Like Factor 4
  • Phosphorylation
  • Proto-Oncogene Proteins c-akt / genetics
  • Proto-Oncogene Proteins c-akt / metabolism
  • Receptor, IGF Type 1 / genetics
  • Receptor, IGF Type 1 / metabolism
  • SOXB1 Transcription Factors / genetics
  • SOXB1 Transcription Factors / metabolism*
  • Signal Transduction
  • Urinary Bladder Neoplasms / genetics
  • Urinary Bladder Neoplasms / metabolism*
  • Urinary Bladder Neoplasms / pathology

Substances

  • IGF1R protein, human
  • KLF4 protein, human
  • Kruppel-Like Factor 4
  • SOX2 protein, human
  • SOXB1 Transcription Factors
  • Insulin-Like Growth Factor II
  • Receptor, IGF Type 1
  • Proto-Oncogene Proteins c-akt