Evaluation of HO-1 expression, cellular ROS production, cellular proliferation and cellular apoptosis in human esophageal squamous cell carcinoma tumors and cell lines

Abstract

Abstract.Patients with esophageal squamous cell carcinoma (ESCC) have a poor prognosis. However, the related mechanisms are unclear, thus we investigated the expression of HO-1 in ESCC tissue and explored possible mechanisms of tumor progression. Expression of HO-1 was examined by immunohistochemistry in 143 ESCC tumors. The correlation of HO-1 with clinicopathological characteristics was also examined. Two human ESCC cell lines, TE-13 and Eca109 were studied. Silencing of cell line HO-1 by specific small interfering RNA (siRNA) was evaluated using real-time quantitative PCR. Cell line viability, apoptosis and intracellular levels of reactive oxygen species (ROS) after transfection were determined using MTT and flow cytometry, respectively. HO-1, Bax, Bcl-2 and A-caspase-3/-9 expression was evaluated using western blot analyses. We found that HO-1 was expressed in 58 of 143 ESCC tumors, mainly in the cytoplasm. There was a significant association between HO-1 expression and tumor grade (P<0.001). Knockdown of HO-1 expression in cell lines was associated with significantly decreased cellular proliferation (P<0.05) and a higher rate of apoptosis (P<0.001) 48 h after treatment. Treatment of the cell lines with the ROS inhibitor N-acetylcysteine abrogated this effect. Knockdown of HO-1 was associated with increased A-caspase-3 and -9 expression, but no change in Bax or Bcl-2 expression or Bax/Bcl-2 ratio was observed. Thus, the present study identified that ESCC tumors frequently expressed HO-1. Knockdown of HO-1 promoted apoptosis through activation of a ROS-mediated caspase apoptosis pathway.

A Dual Role of Heme Oxygenase-1 in Cancer Cells

“…Small interfering RNA (siRNA) and short hairpin RNA (shRNA) are two common approaches on gene silencing via the cleavage of target gene or inhibition of protein synthesis. An intervention of HO-1 expression by shRNA was shown to induce apoptosis in lung cancer cells [109], colon carcinoma cells [45], leukemic cells [95,110], esophageal squamous carcinoma cells [111], and breast cancer cells [112]. In addition, siRNA/shRNA of HO-1 also enhanced the sensitivity to chemotherapy in pancreatic cancers [113,114], lung cancer [109], and breast cancer [112].…”

Heme oxygenase inhibition in cancers: possible tools and targets

“…Of importance, a substantial number of studies evaluating the role of HO-1 inhibition in cancer has been conducted using siRNA or shRNA sequences specifically targeting HO-1 transcript. Application of HO-1 siRNA in vitro resulted in beneficial increase in apoptosis of lung cancer cells [ 61 ], colon carcinoma cells [ 29 ], leukemic cells [ 62 - 64 ] and esophageal squamous carcinoma cells [ 65 ]. Furthermore, increased sensitivity to chemotherapeutics of pancreatic cancer cells [ 10 ], myeloid leukemia cells [ 66 ] and some other types of cancer cells was also reported (reviewed in: [ 27 ]).…”

Acyl-CoA dehydrogenase long chain expression is associated with esophageal squamous cell carcinoma progression and poor prognosis

“…In most parts of the world, esophageal squamous cell carcinoma (ESCC) is the predominant type. 3 , 4 Specifically, in People’s Republic of China, the morbidity and mortality of esophageal cancer are both ranked the fourth. 5 Although there have been developments in ESCC therapy in recent years, ESCC prognosis remains poor due to a lack of obvious early symptoms and detection markers.…”