1. Academic Validation
  2. A novel protein encoded by circular SMO RNA is essential for Hedgehog signaling activation and glioblastoma tumorigenicity

A novel protein encoded by circular SMO RNA is essential for Hedgehog signaling activation and glioblastoma tumorigenicity

  • Genome Biol. 2021 Jan 14;22(1):33. doi: 10.1186/s13059-020-02250-6.
Xujia Wu  # 1 Songhua Xiao  # 2 Maolei Zhang  # 1 Lixuan Yang 1 Jian Zhong 1 Bo Li 3 Fanying Li 1 Xin Xia 1 Xixi Li 1 Huangkai Zhou 1 Dawei Liu 4 Nunu Huang 1 Xuesong Yang 1 Feizhe Xiao 5 Nu Zhang 6
Affiliations

Affiliations

  • 1 Department of Neurosurgery, Institute of Precision Medicine, The First Affiliated Hospital of Sun Yat-sen University; Guangdong Provincial Key Laboratory of Brain Function and Disease, Guangzhou, 510080, Guangdong, China.
  • 2 Department of Neurology, The Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, 510000, Guangdong, China.
  • 3 Department of Biochemistry and Molecular Biology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, Guangdong, China.
  • 4 Department of Pathology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, Guangdong, China.
  • 5 Department of Scientific Research Section, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, Guangdong, China.
  • 6 Department of Neurosurgery, Institute of Precision Medicine, The First Affiliated Hospital of Sun Yat-sen University; Guangdong Provincial Key Laboratory of Brain Function and Disease, Guangzhou, 510080, Guangdong, China. zhangnu2@mail.sysu.edu.cn.
  • # Contributed equally.
Abstract

Background: Aberrant activation of the Hedgehog pathway drives tumorigenesis of many cancers, including glioblastoma. However, the sensitization mechanism of the G protein-coupled-like receptor smoothened (Smo), a key component of Hedgehog signaling, remains largely unknown.

Results: In this study, we describe a novel protein SMO-193a.a. that is essential for Hedgehog signaling activation in glioblastoma. Encoded by circular Smo (circ-SMO), SMO-193a.a. is required for sonic Hedgehog (Shh) induced Smo activation, via interacting with Smo, enhancing SMO Cholesterol modification, and releasing Smo from the inhibition of patched transmembrane receptors. Deprivation of SMO-193a.a. in brain Cancer Stem Cells attenuates Hedgehog signaling intensity and suppresses self-renewal, proliferation in vitro, and tumorigenicity in vivo. Moreover, circ-SMO/SMO-193a.a. is positively regulated by FUS, a direct transcriptional target of Gli1. Shh/Gli1/FUS/SMO-193a.a. form a positive feedback loop to sustain Hedgehog signaling activation in glioblastoma. Clinically, SMO-193a.a. is more specifically expressed in glioblastoma than Smo and is relevant to Gli1 expression. Higher expression of SMO-193a.a. predicts worse overall survival of glioblastoma patients, indicating its prognostic value.

Conclusions: Our study reveals that SMO-193a.a., a novel protein encoded by circular Smo, is critical for Hedgehog signaling, drives glioblastoma tumorigenesis and is a novel target for glioblastoma treatment.

Keywords

Brain cancer stem cells; Circular RNA; Glioblastoma; Hedgehog pathway; Novel protein.

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