Background: Chronic inflammation drives colorectal cancer (CRC) progression, with PAR-2, a G-protein coupled receptor, linking extracellular inflammatory signals to tumor-promoting pathways via ERK1/2 phosphorylation, calcium mobilization, TNF-α upregulation, and apoptosis suppression. While curcumin has notable anti-inflammatory and anti-cancer properties, its effects on PAR-2 signaling in inflammation-driven CRC remain underexplored. Objective: This study investigates how curcumin modulates PAR-2 expression and downstream oncogenic signaling in inflammation-driven CRC cells and explores its potential direct interaction with PAR-2 at the structural level. Methods: HT 29 and Caco-2 CRC cell lines were exposed to lipopolysaccharide (LPS) to induce an inflammatory phenotype, followed by treatment with curcumin at 50 µM and 100 µM. PAR-2 and PAR-1 expression, along with downstream markers including ERK1/2, p-ERK, TNF-α, caspase-8, cleaved caspase-8, caspase-3, Bcl 2, and Bax, were analyzed by Western blot and quantitative PCR. Calcium mobilization was assessed using Fluo-4 dye-based fluorescence imaging. Apoptosis was quantified using MTT viability assays, AO/EtBr dual staining, and Annexin V/PI flow cytometry. In parallel, AlphaFold-predicted structural models of PAR-2 were used to perform molecular docking with curcumin using CB-Dock2, to identify potential binding pockets and assess binding energetics. Results: Curcumin selectively downregulated PAR-2—but not PAR-1—at both transcript and protein levels in a dose-dependent manner. This downregulation was accompanied by suppression of ERK phosphorylation and calcium signaling, inhibition of TNF-α secretion, and reversal of the anti-apoptotic signaling axis (Bcl 2 downregulation and Bax and caspase-3/-8 upregulation). Functional assays confirmed enhanced apoptosis in curcumin-treated cells. Computational docking revealed a high-affinity binding interaction between curcumin and the transmembrane domain of PAR-2, supporting the hypothesis of direct G-Protein-Coupled Receptor (GPCR) modulation. Conclusions: Our findings reveal that curcumin targets the PAR-2/ERK/TNF-α axis and reactivates apoptotic pathways in inflammation-driven CRC, establishing it as a potent, mechanistically validated candidate for therapeutic repurposing in CRC.

Colorectal cancer (CRC) remains a principal contributor to oncological mortality worldwide, with chronic inflammation serving as a fundamental driver of its pathogenesis. Protease-activated receptor-2 (PAR-2), a G-protein-coupled receptor, orchestrates inflammation-driven tumorigenesis by potentiating NF-κB and Wnt/β-catenin signaling, thereby fostering epithelial–mesenchymal transition (EMT), immune evasion, and therapeutic resistance. Despite its pathological significance, targeted modulation of PAR-2 remains an underexplored avenue in CRC therapeutics. Oleocanthal (OC), a phenolic constituent of extra virgin olive oil, is recognized for its potent anti-inflammatory and anti-cancer properties; however, its regulatory influence on PAR-2 signaling in CRC is yet to be elucidated. This study interrogates the impact of OC on PAR-2-mediated inflammatory cascades using HT-29 and Caco-2 CRC cell lines subjected to lipopolysaccharide (LPS)-induced activation of PAR-2. Expression levels of PAR-2 and TNF-α were quantified through Western blotting and RT-PCR, while ELISA assessed TNF-α secretion. Intracellular calcium flux, a pivotal modulator of PAR-2-driven oncogenic inflammation, was evaluated via Fluo-4 calcium assays. LPS markedly elevated PAR-2 expression at both mRNA and protein levels in CRC cells (p < 0.01, one-way ANOVA). OC administration (20–150 μg/mL) elicited a dose-dependent suppression of PAR-2, with maximal inhibition at 100–150 μg/mL (p < 0.001, Tukey’s post hoc test). Concomitant reductions in TNF-α transcription (p < 0.01) and secretion (p < 0.001) were observed, corroborating the anti-inflammatory efficacy of OC. Additionally, OC ameliorated LPS-induced calcium dysregulation, restoring intracellular calcium homeostasis in a concentration-dependent manner (p < 0.01). Crucially, OC exhibited selectivity for PAR-2, leaving PAR-1 expression unaltered (p > 0.05), underscoring its precision as a therapeutic agent. These findings position OC as a selective modulator of PAR-2-driven inflammation in CRC, disrupting the pro-tumorigenic microenvironment through attenuation of TNF-α secretion, calcium dysregulation, and oncogenic signaling pathways. This study furnishes mechanistic insights into OC’s potential as a nutraceutical intervention in inflammation-associated CRC. Given the variability in OC bioavailability and content in commercial olive oil, future investigations should delineate optimal dosing strategies and in vivo efficacy to advance its translational potential in CRC therapy.

Background: Colorectal cancer (CRC) is a growing health concern globally and in regions such as the United Arab Emirates, where risk factors like obesity and hyperlipidaemia are prevalent. Chronic inflammation, driven by pathways involving protease-activated receptor 2 (PAR-2), plays a pivotal role in CRC progression, creating a tumour-promoting microenvironment. The overexpression of PAR-2 has been associated with increased tumour aggressiveness and drug resistance. While previous studies have focused on broad inflammatory modulation, this study explores the selective targeting of PAR-2 by atorvastatin (ATV) and rosuvastatin (RSV), highlighting their specificity by assessing minimal impact on PAR-1 expression, which serves as a control. Methods: HT-29 and Caco-2 CRC cell lines were employed to investigate the anti-inflammatory effects of ATV and RSV. Inflammation was induced with lipopolysaccharide (LPS), followed by treatment with varying concentrations of ATV and RSV. Western blotting and real-time polymerase chain reaction for quantification (qPCR) were performed to quantify PAR-2 and TNF-α at both the protein and mRNA levels. Enzyme linked immunosorbent assay (ELISA) was used to measure the secretion of TNF-α. Calcium signalling, which plays a crucial role in inflammation, was analysed using Fluo-4 AM dye, with fluorescence imaging capturing the effects of statin treatment on intracellular calcium influx. Results: LPS treatment significantly upregulated PAR-2 and TNF-α expression in both cell lines, validating the inflammatory model. Co-treatment with ATV or RSV reduced PAR-2 and TNF-α expression in a dose-dependent manner. The higher concentrations of ATV (50 µg/mL) and RSV (20 µg/mL) produced the most significant reduction in these inflammatory markers at both the protein and mRNA levels. Importantly, the treatment did not substantially alter PAR-1 expression, underlining the specificity of ATV and RSV in modulating PAR-2-mediated pathways. Additionally, statin treatment attenuated LPS-induced calcium influx, with fluorescence intensity decreasing markedly at higher concentrations of both statins. Conclusions: This study provides novel insights into the selective targeting of PAR-2 by ATV and RSV, distinguishing their effects from PAR-1. The reduction in PAR-2 expression and TNF-α secretion, along with the suppression of calcium signalling, underscores the potential of these statins as targeted anti-inflammatory agents in CRC. The findings highlight the therapeutic value of ATV and RSV in modulating inflammation through PAR-2-specific pathways, which may contribute to reduced cancer progression. These results pave the way for further preclinical and clinical evaluations to explore statins as adjunctive therapies in the management of CRC.

Chronic inflammation constitutes a well-established driver of colorectal carcinogenesis, yet the molecular circuitry linking inflammatory receptor signalling to tumour cell survival remains incompletely delineated. Here we demonstrate that the HMG-CoA reductase inhibitors atorvastatin and rosuvastatin modulate inflammatory survival pathways in colorectal cancer cells in a manner consistent with targeted interference with the protease-activated receptor 2 (PAR-2)–extracellular signal-regulated kinase (ERK)–tumour necrosis factor-α (TNF-α) signalling axis. Using lipopolysaccharide-stimulated HT-29 and Caco-2 cells as complementary models of inflammatory colorectal malignancy, we show that both statins selectively attenuate PAR-2 expression at the protein and transcript levels while leaving structurally related PAR-1 unaffected. This pattern of receptor modulation is accompanied by suppression of total ERK1/2 expression, ERK1/2 phosphorylation, and the transcriptional target DUSP6, together with attenuation of TNF-α secretion. Importantly, these signaling shifts are associated with dual apoptotic programs; the extrinsic pathway, reflected by transcriptional upregulation and proteolytic activation of caspase-8; and the intrinsic mitochondrial pathway, evidenced by reciprocal modulation of Bcl-2 family proteins favoring Bax over Bcl-2. Both pathways converge upon activation of executioner caspase-3 and an increase in Annexin V-defined apoptotic fractions, indicating re-engagement of programmed cell death under inflammatory stress. Notably, rosuvastatin consistently demonstrates superior potency across signaling endpoints, achieving comparable biological effects at lower concentrations than atorvastatin. Collectively, these data indicate that clinically deployed statins target the PAR-2–ERK axis and are associated with re-activation of apoptotic pathways in inflammatory colorectal cancer models, while leaving open the possibility that additional statin-responsive networks contribute to their pro-apoptotic effects. This mechanistic framework provides biological plausibility for epidemiologic observations linking statin use with reduced colorectal cancer risk and improved outcomes, and supports further translational evaluation of PAR-2-directed statin strategies in colorectal malignancy.

Osteoarthritis (OA) is a progressive joint disorder affecting over 250 million people globally and is characterized by chronic pain and disability. Among its key pathogenic mechanisms are mitochondrial dysfunction and elevated reactive oxygen species (ROS), often triggered by inflammatory mediators such as lipopolysaccharide (LPS). This study evaluates the protective effects of curcumin on mitochondrial function, autophagy, and apoptosis in an in vitro model of OA. Human bone marrow-derived mesenchymal stem cells (BMSCs) were differentiated into chondrocytes using MesenCult™-ACF medium. Differentiation was confirmed by histological staining for Type II Collagen, Alcian Blue, and Toluidine Blue. LPS was used to induce an OA-like inflammatory response. Mitochondrial membrane potential (ΔΨm) was assessed using Rhodamine 123 staining. Autophagy and apoptosis were evaluated using Acridine orange and propidium iodide staining, respectively. Western blotting was performed to analyze the expression of pro-caspase-3, Bcl-2, Beclin-1, LC3-I/II, and GAPDH. LPS significantly impaired mitochondrial function, limited autophagy, and enhanced apoptotic signaling (reduced pro-caspase-3). Curcumin (25 µM and 100 µM) restored ΔΨm, increased Beclin-1 and LC3-II, and maintained pro-caspase-3 expression, with Bcl-2 showing a non-monotonic response (higher at 25 µM than at 100 µM). Curcumin exerted cytoprotective effects in inflamed chondrocytes by stabilizing ΔΨm, promoting autophagy, and attenuating apoptotic activation, supporting its multi-target therapeutic potential in OA.