Celecoxib can induce cell death independently of cyclooxygenase-2, p53, Mdm2, c-Abl and reactive oxygen species

C1222C Deletion in Exon 8 of ABL1 Is Involved in Carcinogenesis and Cell Cycle Control of Colorectal Cancer Through IRS1/PI3K/Akt Pathway

Colorectal cancer (CRC) is one of the most commonly diagnosed cancers worldwide. ABL1 (c-Abl) is a non-receptor tyrosine kinase, whose role, and molecular mechanism in CRC remain largely unclear. The aim of this study was to elucidate the role of ABL1 to obtain information on colon cancer gene mutation. We analyzed the tissue samples obtained from patients with CRC, CRC cell lines, and the immunodeficient mice. The proliferation, cell cycle, and apoptosis of CRC cells were examined. IPA software was used to analyze the molecules involved in CRC after ABL1 RNA interference. We found ABL1 was highly expressed in CRC tissues and cells. This high expression was associated with the TNM stage of CRC patients. In exon 8 of the ABL1 gene, we identified a novel mutation of C1222C deletion, which was related to the CRC stage. Depletion of ABL1 resulted in the inhibition of proliferation and escalation of apoptosis in two CRC cell lines, SW480, and HCT-116. Our in vivo study also demonstrated that depletion of ABL1 reduced CRC tumor progression. The results of the ingenuity pathway analysis indicated that the expression of 732 genes was upregulated and that of 691 genes was downregulated in mice transplanted with ABL1-downregulated CRC cells, among which we confirmed that depletion of ABL1 inhibited TGF-β1 via IRS1/PI3K/AKT pathway in CRC progression. These findings demonstrated that ABL1 plays an important role and that it can be a potential molecular target for CRC therapy.

Anti-cancer effects of celecoxib in head and neck carcinoma

Although many studies highlighted cyclooxygenase2 (COX2) inhibition as a promising therapeutic strategy for cancer, more evidence is needed for clinical application. The purpose of this study was to investigate the feasibility of COX2 inhibition as a strategic treatment modality for head and neck carcinoma (HNC). We tested COX2 inhibitor, celecoxib in six types of HNC cells and analyzed the expression changes in proteins related to angiogenesis and apoptosis in vitro. We also evaluated proliferation, gelatinolysis and in vitro invasion. We used a hamster carcinogenesis model and a mouse tumorigenesis model for the in vivo evaluation of COX2 inhibition. We performed immunohistochemistry to assess changes in the expression of COX2, survivin and angiogenesis. Celecoxib administration caused decreases in the expressions of COX2, VEGF and survivin in vitro. Proliferation, in vitro invasion and gelatinolytic activity were reduced in HNC cell lines, but the effect was inconsistent across lines. COX2 inhibition retarded oral carcinogenesis from an early carcinogenic stage with increased apoptosis and decreased survivin expression. COX2 inhibition did not inhibit tumor growth, even with the COX2 downregulation and decrease in neovascularization. We conclude that COX2 inhibition has a chemopreventive effect, but its application as a treatment of HNC in a clinical setting still requires further research to overcome its limited anti-cancer effects.

Assessment of celecoxib pharmacodynamics in pancreatic cancer

Cyclooxygenase-2 (COX-2) inhibitors are being developed as chemopreventive and anticancer agents. This study aimed to determine the biological effect of the COX-2 inhibitor celecoxib in pancreatic cancer as an early step to the further development of the agent in this disease. Eight patients scheduled for resection of an infiltrating adenocarcinoma of the pancreas were randomized to receive celecoxib at a dose of 400 mg twice daily or placebo for 5 to 15 days before the surgery. In addition, carcinomas from nine additional patients were xenografted in nude mice, expanded, and treated with vehicle or celecoxib for 28 days. Celecoxib markedly decreased the intra-tumor levels of prostaglandin E2 in patient carcinomas and in the heterotransplanted xenografts. However, this effect did not result in inhibition of cell proliferation or microvessel density (as assessed by Ki67 and CD31 staining). In addition, a panel of markers, including bcl-2, COX-1, COX-2, and VEGF, did not change with treatment in a significant manner. Furthermore, there was no evidence of antitumor effects in the xenografted carcinomas. In summary, celecoxib efficiently inhibited the synthesis of prostaglandin E2 both in pancreatic cancer surgical specimens and in xenografted carcinomas but did not exert evident antitumor, antiproliferative, or antiangiogenic effect as a single agent. The direct pancreatic cancer xenograft model proved to be a valuable tool for drug evaluation and biological studies and showed similar results to those observed in resected pancreatic cancer specimens.

Luminal delivery and dosing considerations of local celecoxib administration to colorectal cancer

The purpose of this study was to develop a biodegradable drug platform composed of chitosan and guar gum and to explore the possibility of using it for local adjuvant or neoadjuvant therapy of colorectal cancer. Celecoxib (Cx), a chemopreventative drug for familial adenomatous polyposis (FAP) and under trial for reducing post surgical colorectal malignancies, was selected as a model drug for this topical system because of the contraindications that are associated with its systemic administration. Films made of chitosan (Ct) and guar gum (GG) were prepared, characterized for equilibrium swelling, mucoadhesion, in vitro and in vivo degradation and loaded with Cx. Short term dosing studies in vitro were performed in the HT-29 colon carcinoma cell line that was incubated with Cx using the MTT test to assess IC50. The impact of a single high dose was evaluated and compared with a repeating low-dose regimen. In vivo dosing experiments with Cx were performed in the perfused intestine of the anaesthetized rat. Measuring tissue LDH assessed epithelium injury. Mechanical, mucoadhesion and in vitro degradation of the polysaccharide films were dictated by manipulating the ratios of Ct and GG. The addition of rat cecal contents to the dissolution medium increased the total Cx released from those films containing high amounts of GG. MTT reduction, a measure of cell proliferation, diminished as a function of increasing drug concentration and exposure time in the HT-29 cell line studies. Local high concentrations of Cx were shown to impede the proliferation of cancer cells directly, while chemoprevention has been demonstrated with low Cx doses. Healthy cells were shown to be sensitive to high Cx doses. Maximum therapeutic efficiency in the context of minimal healthy tissue exposure would thus be predicted utilizing a local delivery system such as the proposed adhesive, biodegradable polysaccharide composites.