Antitumorigenic effect of plumbagin by induction of SH2-containing protein tyrosine phosphatase 1 in human gastric cancer cells

Abstract

A recent study reported that plumbagin downregulated the activity of Janus kinase 2 (JAK2)-signal transducer and activator of transcription 3 (STAT3) pathway to show various antitumor effects in multiple myeloma cells. We aimed in this in vitro study to demonstrate the inhibition of JAK2/STAT3 pathway by plumbagin through inducing SH2-containing protein tyrosine phosphatase 1 (SHP1) expression in the MKN-28 gastric cancer cell line. We performed western blot analysis to measure SHP1, phosphor-JAK2/STAT3 level, and observed that plumbagin induced SHP1 expression and simultaneously downregulated phosphor-JAK2/STAT3 in MKN-28 cells, with negative SHP1 expression. This effect was consistent when JAK2/STAT3 signaling was activated by interleukin-6 (IL-6), and ameliorated when cells were treated with prevanadate, a protein tyrosin phosphatase inhibitor. Furthermore, plumbagin significantly reduced gene expression of cyclin D1, vascular endothelial growth factor (VEGF)-1, Bcl-xL, survivin and matrix metalloproteinase-9 (MMP-9), known target products of STAT3 activation in gastric carcinogenesis by reverse transcription-polymerase chain reaction (RT-PCR). Several functional studies such as water soluble tetrazolium salt-1 (WST-1) assay, wound closure assay, Matrigel invasion assay and Annexin V assay were also performed, and we validated the functional effect of plumbagin for inhibition of cell proliferation, migration and invasion, and induction of apoptosis. Collectively, our findings suggest that plumbagin is a potential regulator of cellular growth, migration, invasion and apoptosis by inhibiting both constitutive and inducible STAT3 activity through induction of SHP1 in gastric cancer cells.

Plumbagin, a natural naphthoquinone, inhibits the growth of esophageal squamous cell carcinoma cells through inactivation of STAT3

“…Targeting STAT3 signaling represents an important molecular mechanism for the anticancer activity of plumbagin in melanoma (18), gastric cancer (17), breast cancer (8), and prostate cancer (25). In line with these studies, the present data demonstrated that plumbagin treatment significantly suppressed STAT3 activation in EScc cells.…”

“…Plumbagin has exhibited anticancer properties in many types of cancer, including breast cancer (8), pancreatic cancer (9), prostate cancer (16), and gastric cancer (17). It has been reported that plumbagin can block prostate carcinogenesis triggered by loss of phosphatase and tensin homolog (PTEN) (16).…”

TMEM119 promotes gastric cancer cell migration and invasion through STAT3 signaling pathway

“… 39 A previous study demonstrated that gastric cancer cells expressing high levels of STAT3 also expressed high levels of VEGF, indicating a positive correlation between the expression levels of STAT3 and VEGF. 40 This is consistent with our findings that blocking STAT3 signal significantly inhibited TMEM119-induced VEGF expression in gastric cancer cells, which resulted in decreased cell migration and invasion. Moreover, blocking the activation of STAT3 in gastric cancer cells resulted in corresponding decrease in VEGF protein expression, which in turn resulted in decreased metastasis and invasion of gastric cancer cells.…”

The roles of HOXB7 in promoting migration, invasion, and anti‐apoptosis in gastric cancer

“…Complementary DNA (cDNA) was subsequently produced using a high‐capacity cDNA reverse transcription kit (Applied Biosystems, Foster City, CA, USA) and treatment with 1 U DNase (Promega Corp., Madison, WI, USA). Reverse transcription polymerase chain reaction (RT‐PCR) was performed using a previously described method with modification . Briefly, 20 ng of cDNA was used to generate 25 μL of PCR product using Econo Taq ® PLUS Green Master Mix (Lucigen Co., Middleton, WI, USA).…”

“…Reverse transcription polymerase chain reaction (RT-PCR) was performed using a previously described method with modification. 18 Briefly, 20 ng of cDNA was used to generate 25 μL of PCR product using Econo Taq ® PLUS Green Master Mix (Lucigen Co., Middleton, WI, USA). PCR was performed under the following conditions: initial denaturation at 94°C for 2 min, followed by 40 cycles of denaturation at 94°C for 15 s, annealing at 55°C for 15 s, and extension at 72°C for 15 s, and a final extension at 72°C for 10 min.…”