Anticancer effect of cucurbitacin B on MKN-45 cells via inhibition of the JAK2/STAT3 signaling pathway

Abstract

The aim of the present study was to investigate the effect of cucurbitacin B on MKN-45 gastric carcinoma cells. Cell proliferation was determined using a cell counting kit-8 assay, and commercial cell cycle and apoptosis analysis kits were used to determine the cell cycle by flow cytometry. The mRNA expression of genes which mediate cell cycle checkpoints and apoptosis was detected using reverse transcription-quantitative polymerase chain reaction, and a terminal deoxynucleotidyl transferase dUTP nick end labeling assay was used to determine apoptosis rate. Western blot analysis was used to detect the protein expression levels of JAK2/STAT3 signaling pathway-associated proteins. The presented data show that cucurbitacin B significantly inhibited the proliferation of MKN-45 cells in a dose- and time-dependent manner. In accordance with these findings, cucurbitacin B blocked the progression of the cell cycle from G0/G1 to S phase, which was confirmed by the mRNA expression analysis. Cucurbitacin B treatment significantly suppressed the expression of cyclin D1, cyclin E, cyclin-dependent kinase 4 (CDK4) and CDK2, while increasing the expression of p27. Cucurbitacin B also promoted cell apoptosis, as was determined by TUNEL assay and evaluation of mRNA expression. Further experiments suggested that the beneficial effect of cucurbitacin B on blocking the proliferation and inducing the apoptosis of MKN-45 cells may have been associated with suppression of the JAK2/STAT3 signaling pathway. Thus, the present results indicate that cucurbitacin B suppresses proliferation and promoted apoptosis of MKN-45 cells, which may be mediated by inhibition of the JAK2/STAT3 signaling pathway. Cucurbitacin B therefore may warrant further investigation as a feasible therapy for gastric carcinoma.

Naturally occurring anti-cancer compounds: shining from Chinese herbal medicine

“…Cucurbitacin B is the most abundant source of cucurbitacins which can explain why it receives more attention from researchers than other cucurbitacins do. It suppresses cell proliferation and enhances apoptosis in human NSCLC A549 cells, colorectal cancer SW-480 and Caco-2 cells [462,477], and induces G1 phase cell cycle arrest in human colorectal cancer SW-480 and Caco-2, and gastric cancer MKN45 cells [477,478]. Cucurbitacin D inhibits cell survival in human gastric cancer AGS, SNU1 and Hs746T cells [479], while cucurbitacin E induces cell cycle arrest at G2/M phase in triple negative breast cancer cells [480].…”

Cucurbitacin B and cancer intervention: Chemistry, biology and mechanisms (Review)

“…This was supported with downregulation of cyclin B1, phospho-STAT3 and BCL2, associated with chromatin condensation, nuclear fragmentation, and appearance of apoptotic bodies in a dose-and time-dependent manner. Cucurbitacin B inhibited proliferation and induced G 0 /G 1 cell cycle arrest in a dose-and time-dependent manner in gastric cancer cells (88). It suppressed the expression of cyclin D1, cyclin E, CDK4 and CDK2 and upregulated the expression of p27, all of which are indicated in inhibition of cell cycle progression.…”

“…Mitochondrial translocation of STAT3 constitutively suppressed autophagy. Studies reported that cucurbitacin B and derivatives interfered with the activation of STAT3 (61,63,74,82,87,88,94,95,98,99,(102)(103)(104)(105)109,110,119,130). Autophagy signaling is a fairly new subject.…”

MLAA-34 knockdown shows enhanced antitumor activity via JAK2/STAT3 signaling pathway in acute monocytic leukemia

“… 12 , 13 , 18 . Therefore, the JAK2/STAT3 pathway is considered a target for anticancer therapy in many human cancers 10 , 18 - 20 . Our findings revealed that knockdown of MLAA-34 were accompanied by the decreased expression of JAK2/STAT3 signaling molecules.…”