Aryl hydrocarbon receptor (AhR) and pregnane X receptor (PXR) play both distinct and common roles in the regulation of colon homeostasis and intestinal carcinogenesis

Nanoliposome-loaded phenolics from Salvia leriifolia Benth and its anticancer effects against induced colorectal cancer in mice

Colon cancer is one of the leading causes of death among various types of cancer. Despite the significant progress made in cancer treatment, chemotherapy resistance and various side effects are still prevalent. The objective of this study is to assess the therapeutic potential of phenolic-rich fraction encapsulated nanoliposome (PRF-NLs) of Salvia leriifolia Benth in the treatment of colon cancer in mice. Initially, the phenolic-rich fraction (PRF) was extracted and then encapsulated into nanoliposomes. The physicochemical properties of the nanoliposomes were evaluated using dynamic light scattering, zeta potential, and field emission scanning electron microscopy. Subsequently, 24 mice with HT-29 colon cancer cells were divided into three groups, and the anticancer effects of PRF-NLs were measured. The results showed that the ethyl acetate fraction of S. leriifolia was the highest PRF containing 14.27 ± 2.39 mg (gallic acid) GA/g DW (dry weight), and the PRF successfully loaded into the nanoliposome structure resulted in the synthesis of nanoliposomes with a nanometer size and spherical shape and homogenous dispersion. Some of the abundant bioactive phenolic compounds in the nanoliposome-loaded PRF are salicylic acid and naringin. The average daily weight gain and food intake, and changes in the expression of caspase 3, Bax (Bcl-2 associated X-protein), and Bcl2 (B-cell lymphoma 2), inducible nitric oxide synthase genes, were observed in the mice group induced colorectal cancer cells. At a dose of 100 mg TPC (total phenolic content)/kg BW/day, the nonencapsulated PRF dietary addition improved these parameters; however, the potential shown by nanoliposome-encapsulated PRF than the nonencapsulated PRF in enhancing health parameters in mice was higher. The developed intestinal absorption and bioavailability of nanoliposome-encapsulated PRF contribute to its increased health-promoting activity. Thereby, the synthesized nanoliposome may be a potential natural anticancer drug to prevent colorectal cancer.

In vitro safety signals for potential clinical development of the anti-inflammatory pregnane X receptor agonist FKK6

Based on the mimicry of microbial metabolites, functionalized indoles were demonstrated as the ligands and agonists of the pregnane X receptor (PXR). The lead indole, FKK6, displayed PXR-dependent protective effects in DSS-induced colitis in mice and in vitro cytokine-treated intestinal organoid cultures. Here, we report on the initial in vitro pharmacological profiling of FKK6. FKK6-PXR interactions were characterized by hydrogen-deuterium exchange mass spectrometry. Screening FKK6 against potential cellular off-targets (G protein-coupled receptors, steroid and nuclear receptors, ion channels, and xenobiotic membrane transporters) revealed high PXR selectivity. FKK6 has poor aqueous solubility but was highly soluble in simulated gastric and intestinal fluids. A large fraction of FKK6 was bound to plasma proteins and chemically stable in plasma. The partition coefficient of FKK6 was 2.70, and FKK6 moderately partitioned into red blood cells. In Caco2 cells, FKK6 displayed high permeability (A-B: 22.8 × 10-6 cm.s-1) and no active efflux. These data are indicative of essentially complete in vivo absorption of FKK6. The data from human liver microsomes indicated that FKK6 is rapidly metabolized by cytochromes P450 (t1/2 5 min), notably by CYP3A4. Two oxidized FKK6 derivatives, including DC73 (N6-oxide) and DC97 (C19-phenol), were detected, and these metabolites had 5-7 × lower potency as PXR agonists than FKK6. This implies that despite high intestinal absorption, FKK6 is rapidly eliminated by the liver, and its PXR effects are predicted to be predominantly in the intestines. In conclusion, the PXR ligand and agonist FKK6 has a suitable pharmacological profile supporting its potential preclinical development.