Title:Nimbolide, a Neem Limonoid, Inhibits Angiogenesis in Breast Cancer by Abrogating
Aldose Reductase Mediated IGF-1/PI3K/Akt Signalling
Volume: 22
Issue: 14
Author(s): Ramesh Nivetha, Soundararajan Arvindh, Abdul Basit Baba, Deepak Reddy Gade, Gopisetty Gopal, Chitrathara K, Kallamadi Prathap Reddy, G. Bhanuprakash Reddy and Siddavaram Nagini*
Affiliation:
- Department of Biochemistry & Biotechnology, Faculty of Science, Annamalai University, Annamalainagar-608002, Tamil Nadu, India
Keywords:
Aldose reductase, angiogenesis, breast cancer, IGF-1, nimbolide, PI3K/Akt.
Abstract:
Background & Objective: The insulin/IGF-1R/PI3K/Akt signalling cascade is increasingly being linked to
breast cancer development, with aldose reductase (AR) playing a key role in mediating the crosstalk between this
pathway and angiogenesis. The current study was designed to investigate whether nimbolide, a neem limonoid, targets
the oncogenic signaling network to prevent angiogenesis in breast cancer.
Methods: Breast cancer cells (MCF-7, MDA-MB-231), EAhy926 endothelial cells, MDA-MB-231 xenografted nude
mice, and tumour tissues from breast cancer patients were used for the study. The expression of AR and key players in
IGF-1/PI3K/Akt signaling and angiogenesis was evaluated by qRT-PCR, immunoblotting, and immunohistochemistry.
Molecular docking and simulation, overexpression, and knockdown experiments were performed to determine whether
nimbolide targets AR and IGF-1R.
Results: Nimbolide inhibited AR with consequent blockade of the IGF-1/PI3K/Akt and /HIF-1alpha/VEGF signalling
circuit by influencing the phosphorylation and intracellular localisation of key signaling molecules. The downregulation
of DNMT-1, HDAC-6, miR-21, HOTAIR, and H19 with the upregulation of miR-148a/miR-152 indicated that
nimbolide regulates AR and IGF-1/PI3K/Akt signaling via epigenetic modifications. Coadministration of nimbolide
with metformin and the chemotherapeutic drugs tamoxifen/cisplatin displayed higher efficacy than single agents in
inhibiting IGF-1/PI3K/Akt/AR signaling. Grade-wise increases in IGF-1R and AR expression in breast cancer tissues
underscore their value as biomarkers of progression.
Conclusion: This study provides evidence for the anticancer effects of nimbolide in cellular and mouse models of
breast cancer besides providing leads for new drug combinations. It has also opened up avenues for investigating potential
molecules such as AR for therapeutic targeting of cancer.