Chebulinic acid inhibits MDA-MB-231 breast cancer metastasis and promotes cell death through down regulation of SOD1 and induction of autophagy.

Triple-negative breast cancers (TNBC) are highly aggressive and drug resistant accounting for majority of cases with poor outcome. Purified natural compounds display substantial anticancer activity with reduced cytotoxicity providing a new avenue to combat TNBC. Chebulinic acid (CA), a polyphenol derived from the fruits of various medicinal plants has potent anticancer activity. Here, we demonstrate that CA shows significant cytotoxicity against triple negative MDA-MB-231 cells. CA exhibited cytotoxicity to MDA-MB-231 cells in 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Further, CA mitigated MDA-MB-231 cells viability and proliferation as shown by reduced live cell count, crystal violet staining, colony formation assay, soft agar assay and cell cycle analysis. Wound healing assay and trans-well migration assay demonstrated that CA significantly inhibited migration of MDA-MB-231 cells. Also reduced MMP9 expression was observed in CA-treated cells by gelatin zymography. CA negatively regulated mesenchymal characteristics of MDA-MB-231 cells demonstrated by F-actin staining and reduced expression of N-cadherin by confocal microscopy and western blot analysis. Annexin V/propidium iodide (PI) and active caspase-3 staining showed that CA was able to induce apoptosis in MDA-MB-231 cells but did not activate caspase-3. Two-dimensional gel electrophoresis based proteomic analysis demonstrated that CA regulated proteins belonging to the oxidative stress pathway, apoptotic pathway and proteins with antiproliferative activity. Western blot analysis analysis revealed that CA negatively regulated superoxide dismutase 1 (SOD1) and enhanced oxidative stress in MDA-MB-231 cells. SOD1 in-gel activity assay also showed reduced SOD1 activity upon CA treatment. Overexpression studies with GFP-LC3 and tandem tagged RFP-GFP-LC-3 also demonstrated enhanced autophagy upon CA treatment.

Chebulinic Acid Isolated From the Fruits of Terminalia chebula Specifically Induces Apoptosis in Acute Myeloid Leukemia Cells.

Chebulinic acid, an ellagitannin found in the fruits of Terminalia chebula, has been extensively used in traditional Indian system of medicine. It has shown to have various biological activities including antitumor activity. The present study aims to investigate the cytotoxic potential of chebulinic acid in human myeloid leukemia cells. Interestingly, chebulinic acid caused apoptosis of acute promyelocytic leukemia HL-60 and NB4 cells but not K562 cells. In vitro antitumor effects of chebulinic acid were investigated by using various acute myeloid leukemia cell lines. Chebulinic acid treatment to HL-60 and NB4 cells induced caspase activation, cleavage of poly(ADP-ribose) polymerase, DNA fragmentation, chromatin condensation, and changes in the mitochondrial membrane permeability. Additionally, inhibition of caspase activation drastically reduced the chebulinic acid-induced apoptosis of acute promyelocytic leukemia cells. Our data also demonstrate that chebulinic acid-induced apoptosis in HL-60 and NB4 cells involves activation of extracellular signal-regulated kinases, which, when inhibited with ERK inhibitor PD98059, mitigates the chebulinic acid-induced apoptosis. Taken together, our findings exhibit the selective potentiation of chebulinic acid-induced apoptosis in acute promyelocytic leukemia cells. Copyright © 2017 John Wiley & Sons, Ltd.

Guava fruit extract and its triterpene constituents have osteoanabolic effect: Stimulation of osteoblast differentiation by activation of mitochondrial respiration via the Wnt/ß-catenin signaling.

The aim of this study was to evaluate the skeletal effect of guava triterpene-enriched extract (GE) in rats and identify osteogenic compounds thereof, and determine their modes of action. In growing female rats, GE at 250 mg/kg dose increased parameters of peak bone mass including femur length, bone mineral density (BMD) and biomechanical strength, suggesting that GE promoted modeling-directed bone growth. GE also stimulated bone regeneration at the site of bone injury. In adult osteopenic rats (osteopenia induced by ovariectomy, OVX) GE completely restored the lost bones at both axial and appendicular sites, suggesting a strong osteoanabolic effect. Serum metabolomics studies showed changes in several metabolites (some of which are related to bone metabolism) in OVX compared with ovary-intact control and GE treatment to OVX rats reversed those. Out of six abundantly present triterpenes in GE, ursolic acid (UA) and 2α-hydroxy ursolic acid (2α-UA) induced osteogenic differentiation in vitro as did GE by activating Wnt/ß-catenin pathway assessed by phosphorylation of GSK-3ß. Over-expressing of constitutively active GSK-3ß (caGSK-3ß) in osteoblasts abolished the differentiation-promoting effect of GE, UA and 2α-UA. All three increased both glycolysis and mitochondrial respiration but only rotenone (inhibitor of mitochondrial electron transfer) and not 2-deoxyglucose (to block glycolysis) inhibited osteoblast differentiation. In addition, caGSK-3ß over-expression attenuated the enhanced mitochondrial respiration caused by GE, UA and 2α-UA. We conclude that GE has osteoanabolic effect which is contributed by UA and 2α-UA, and involve activation of canonical Wnt signaling which in turn modulates cellular energy metabolism leading to osteoblast differentiation.