Implication of connexin30 on the stemness of glioma: connexin30 reverses the malignant phenotype of glioma by modulating IGF-1R, CD133 and cMyc
Authors: Shantha Ravisankar
Arambakkam Janardhanam Vanisree
Sankaradoss Arun
Journal: Journal of Neuro-Oncology (2017)
Discipline: NEUROSCIENCE & BEHAVIOR
Keywords: CD133; Connexin30; Glioma; IGF-1R; cMyc.
Affiliations: Department of Biochemistry, University of Madras, Guindy Campus, Chennai, Tamil Nadu, 600 025, India., Department of Neuropathology, Tamil Nadu Multi-Specialty Hospital, Chennai, Tamil Nadu, 600 003, India., Department of Biochemistry, University of Madras, Guindy Campus, Chennai, Tamil Nadu, 600 025, India. .

Abstract:  Gap-junctional intercellular communication (GJIC) plays a major role in the malignant growth of glioma. Although the mechanistic aspects of GJIC have been extensively studied, the role of connexins in the regulation of the malignant behavior of glioma stem cells (GSCs) remains unclear. In our previous studies, we have shown that connexin30 can interfere with the insulin-like growth factor 1 receptor (IGF-1R), which is known for self-renewal and pluripotency. Following our earlier in vitro observation, in this work, we aimed to study the consequence of this influence of Cx30 on IGF-1R by evaluating the marker of GSCs, CD133 and oncoprotein, cMyc. We strengthened our basis by examining human glioma samples of different grades as well as rat C6 xenografts (Cx30-transfected and -non-transfected C6 cells) along with the sphere formation assays in vitro. Investigation of stemness-related CD133 and cMyc in human samples and rat xenografts exhibited a reciprocal relationship between Cx30 and IGF-1R in the low and high grades (HG) of glioma. Cx30 was completely abolished in HG; levels of IGF-1R, CD133 and cMyc expression were positively correlated with HG. Cx30 transfection could attenuate the malignant burden of glioma in rat xenografts. Cx30 transfection also altered the tumor sphere formation of C6 glioma cells in vitro, an important property of GSCs, and there was a significant reduction of CD133 and cMyc expression by Cx30 both in vitro and in vivo. These factors indicate that dysfunction of Cx30 plays a crucial role in the prevention of the stemness of glioma, and the exploitation of this feature will help in the management of glioma. 

Retracted: No

PubPeer comments:
 Concerns about Figure 1 and Figure 4: 1. The pmTOR panels from b (grade I) and c (grade II) in Figure 1 look very similar to each other. Shown with red boxes. 2. The Cx30 panel from b (grade I) in Figure 1 looks very similar to the IGF3 panel from C6 cells-implanted rats in Figure 4. Shown with blue boxes. ![file] , 
 Figure 2. Two of the control panels look very similar to each other. Shown with green boxes. Two of the C6 cells implanted rats look very similar to each other. Shown with orange boxes. ![file] , 
 A correction was published on March 24, 2020: https: link.springer.com article 10.1007%2Fs11060-021-03743-5  During the initial online submission, owing to an alignment error, Fig. 1 Cx30 panel b overlapped on Fig. 4 IGF-1R panel b; the correct Fig. 4 appears below. ![file] The authors sincerely regret this error. -- None of the other issues were addressed and the newly added image looks very different from the other images with the same antibody. The same problem appears throughout the images in the manuscript. ,