Curcumin Inhibits Proliferation of Renal Cell Carcinoma in vitro and in vivo by Regulating miR-148/ADAMTS18 through Suppressing Autophagy

Curcuma Longa: Nutraceutical Use and Association With Nanotechnology

Curcumin is a natural product found in the rhizome of Curcuma longa (L.) and other Curcuma spp. As a lipophilic molecule, it has greater affinity for polar, non-polar, alkaline, or extremely acidic organic solvents. Several studies indicate that curcumin has several benefits for human health, for example, against degenerative diseases, cancer, and infectious diseases. To obtain a quality product with nutraceutical properties, it is necessary to know its physicochemical characteristics and preserve it from cultivation until ingestion by the human. However, its low solubility leads to low absorption; in this context, nanotechnological systems can contribute to increase curcumin bioavailability. This review aims to highlight important issues in all stages that curcumin goes through: from aspects related to its extraction to its association with nanotechnology. Although curcumin extraction process is already well established, it is possible to observe more and more research focused on increasing yield and being more environmentally friendly. Further, curcumin's low absorption is notable due to its physicochemical characteristics, mainly due to its low aqueous solubility. However, its association with nanotechnology shows to be promising and an increasingly growing trend because the use of this "Indian solid gold" is the hope of many patients.

Curcumin and its anti-colorectal cancer potential: From mechanisms of action to autophagy

Colorectal cancer (CRC) development and progression, one of the most common cancers globally, is supported by specific mechanisms to escape cell death despite chemotherapy, including cellular autophagy. Autophagy is an evolutionarily highly conserved degradation pathway involved in a variety of cellular processes, such as the maintenance of cellular homeostasis and clearance of foreign bodies, and its imbalance is associated with many diseases. However, the role of autophagy in CRC progression remains controversial, as it has a dual function, affecting either cell death or survival, and is associated with cellular senescence in tumor therapy. Indeed, numerous data have been presented that autophagy in cancers serves as an alternative to cell apoptosis when the latter is ineffective or in apoptosis-resistant cells, which is why it is also referred to as programmed cell death type II. Curcumin, one of the active constituents of Curcuma longa, has great potential to combat CRC by influencing various cellular signaling pathways and epigenetic regulation in a safe and cost-effective approach. This review discusses the efficacy of curcumin against CRC in vitro and in vivo, particularly its modulation of autophagy and apoptosis in various cellular pathways. While clinical studies have assessed the potential of curcumin in cancer prevention and treatment, none have specifically examined its role in autophagy. Nonetheless, we offer an overview of potential correlations to support the use of this polyphenol as a prophylactic or co-therapeutic agent in CRC.

The progression of obstructive renal fibrosis in rats is regulated by ADAMTS18 gene methylation in the embryonic kidney through the AKT/Notch pathway

This study aimed to explore the mechanism by which postembryonic renal ADAMTS18 methylation influences obstructive renal fibrosis in rats. After exposure to transforming growth factor (TGF)-β1 during the embryonic period, analysis of postembryonic renal ADAMTS18 methylation and expression levels was conducted. Histological analysis was performed to assess embryonic kidney lesions and damage. Western blot analysis was used to determine the expression of renal fibrosis markers. Rats with ureteral obstruction and a healthy control group were selected. The methylation levels of ADAMTS18 in the different groups were analyzed. Western blot analysis and immunohistochemistry were performed to analyze the expression of renal fibrosis markers, and kidney-related indicators were measured. Treatment with TGF-β1 resulted in abnormal development of the postembryonic kidney, which was characterized by rough kidney surfaces with mild depressions and irregularities on the outer surface. TGF-β1 treatment significantly promoted ADAMTS18 methylation and activated the protein kinase B (AKT)/Notch pathway. Ureteral obstruction was induced to establish a renal hydronephrosis model, which led to renal fibrotic injury in newborn rats. Overexpression of the ADAMTS18 gene alleviated renal fibrosis. The western blot results showed that compared to that in the control group, the expression of renal fibrosis markers was significantly decreased after ADAMTS18 overexpression, and there was a thicker renal parenchymal tissue layer and significantly reduced p-AKT/AKT and Notch1 levels. TGF-β1 can induce ADAMTS18 gene methylation in the postembryonic kidney, and the resulting downregulation of ADAMTS18 expression has long-term effects on kidney development, potentially leading to increased susceptibility to obstructive renal fibrosis. This mechanism may involve activation of the AKT/Notch pathway. Reversing ADAMTS18 gene methylation may reverse this process.

Curcumin Interferes with TGF- β 1-Induced Fibrosis in NRK-49F Cells by Reversing ADAMTS18 Gene Methylation

OBJECTIVE

To explore the molecular mechanism by which curcumin affects renal interstitial fibrosis (RIF) progression by regulating ADAM metallopeptidase with thrombospondin type 1 motif 18 (ADAMTS18) methylation.

METHODS

NRK-49F cells RIF model were induced with transforming growth factor β 1 (TGF- β 1). Effects of different concentrations of curcumin (0, 10, 20, and 30 μmol/L) on cell proliferation, cell cycle, cell apoptosis as well as cyclin D1 expression were analyzed by cell counting kit-8, flow cytometry and Western blot, respectively. ADAMTS18 methylation levels were determined by methylation-specific polymerase chain reaction. ADAMTS18, fibronectin (FN), type I collagen (Col- I) and alpha-smooth muscle actin (α -SMA) mRNA and protein expressions were analyzed by real-time PCR (RT-PCR) and Western blot, respectively. Meanwhile, cells were treated with 50 mmol/L 5-aza-2'-deoxycytidine (5-aza-dC, demethylation agent) for 72 h. Effect of curcumin on extracellular matrix (ECM) deposition was evaluated by immunochemical staining and Western blot. NRK-49F cells were transfected with ADAMTS18 small interfering RNA and grouped into a normal control, ADAMTS18-knock-out (KO), and ADAMTS18-KO+ 30 μmol/L curcumin groups, and whether curcumin can reverse the effect of ADAMTS18 knockdown on RIF was evaluated.

RESULTS

Compared with the control group, TGF-β 1 significantly inhibited the proliferation of NRK-49F cells, blocked the G1/G0 phase, promoted cell apoptosis and inhibited cyclin D1 expression (P<0.01). Among the different concentrations of curcumin, 30 μmol/L curcumin significantly reversed these processes (P<0.01). Immunochemical staining and Western blot results showed that curcumin significantly inhibited the deposition of FN, Col- I and α-SMA (P<0.01). Curcumin and 5-zaz-dC had synergistic effects, promoting ADAMTS18 expression, removing ADAMTS18 methylation, and reducing ECM deposition. ADAMTS18 knockdown promoted ECM accumulation, and curcumin reversed this process (P<0.01).

CONCLUSION

TGF-β 1-induced fibrosis in NRK-49F cells. Curcumin promoted ADAMTS18 expression, reduced ECM accumulation, and alleviated RIF progression by inhibiting ADAMTS18 methylation.