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Molecular basis of cholesterol feedback lesion in CNS tumours
1Department of Experimental Medicine, Biotechnology and Neurosurgery, Postgraduate Institute of Medical Education and Research, Chandigarh, 160012, India.
Abstract:
An important feature of malignant transformation of tumours is the loss of cholesterol feedback inhibition mechanism (cholesterol-feedback lesion) that regulates mevalonate pathway recognized to play a crucial role in cellular growth, death and differentiation. Recently, it was shown that Receptor-C(k)-dependent signalling regulates genes involved in maintaining cellular cholesterol homeostasis through a transcription factor sterol response element binding protein (SREBP) having affinity for sterol regulatory element (SRE) present in the promoter region of these genes. The present study revealed that CNS tumours exhibit overexpression of Receptor-C(k) gene product which was accompanied by their inability to express SREBP gene product and this phenomenon has the inherent capacity to initiate the cholesterol feedback lesion in these tumours. Based upon these and our earlier studies, we propose for the first time that this loss of cholesterol feedback control may be responsible for the initiation of these tumours.
Insights
Loss of cholesterol feedback control in brain tumors may initiate cancer. Overexpression of Receptor-C(k) and lack of sterol response element binding protein (SREBP) expression disrupt cholesterol homeostasis, leading to tumor development.
Area of Science:
- Oncology
- Molecular Biology
- Biochemistry
Background:
- Malignant transformation involves loss of cholesterol feedback inhibition, crucial for the mevalonate pathway regulating cell growth.
- Receptor-C(k)-dependent signaling influences cholesterol homeostasis via sterol response element binding protein (SREBP) and sterol regulatory element (SRE).
Purpose of the Study:
- To investigate the role of Receptor-C(k) and SREBP in the cholesterol feedback lesion in central nervous system (CNS) tumors.
- To determine if altered cholesterol regulation contributes to CNS tumor initiation.
Main Methods:
- Analysis of Receptor-C(k) and SREBP gene product expression in CNS tumors.
- Correlation of gene expression with the presence of a cholesterol feedback lesion.
Main Results:
- CNS tumors showed overexpression of the Receptor-C(k) gene product.
- These tumors exhibited an inability to express the SREBP gene product.
- This molecular alteration initiates the cholesterol feedback lesion in CNS tumors.
Conclusions:
- The loss of cholesterol feedback control, driven by Receptor-C(k) overexpression and SREBP deficiency, is proposed as a key initiator of CNS tumors.
- This finding offers a novel perspective on the molecular mechanisms underlying brain tumor development.