Indomethacin acts as an antitumor and anticachexic agent in colon 26-bearing CDF1 mice

Effects of combined treatment with Indomethacin and Juglone on AOM/DSS induced colon carcinogenesis in Balb/c mice: Roles of inflammation and apoptosis

AIM

Indomethacin [IND] is reported to treat colon cancer. However, continuous exposure to IND causes gastric ulceration, an adverse side effect in humans. This study implies the therapeutic effect of IND and juglone [JUG] against colon carcinogenesis, without gastric ulceration - an adverse side effect of IND.

MATERIALS AND METHODS

Adult male Balb/C mice were divided into six groups randomly: control, AOM/DSS-induced, IND-treated, JUG-treated, IND + JUG-treated and drug-control. Levels of serum markers, haematoxylin & eosin staining to observe tissue architecture, toluidine blue staining to detect mast cells expression, Masson's trichrome and sirius-red staining were used to detect the collagen deposition. RT-PCR and western blot analysis were carried out to detect inflammation and apoptosis.

KEY FINDINGS

IND + JUG effectively decreased the levels of serum markers: CEA, AFP, LDH, AST and ALT. Although, IND restored colonic architecture by regulating the accumulation of mast cell and collagen content, it causes gastric ulceration. To address this adverse effect of IND, JUG was given along with IND and was shown to alleviate IND-induced gastric ulceration. AOM/DSS induced animals showed increased expression of inflammatory molecules - TNFα, NFκB and Cox-2, apoptosis regulator - Bcl-2 and decreased expression of pro-apoptotic molecules - Bad, Bax and caspase3; whereas, IND and JUG treated groups showed decreased inflammatory expression with increased expression of pro-apoptotic molecules.

SIGNIFICANCE

IND and JUG reduce the inflammatory activity and induce apoptotic cell death, while JUG effectively prevents IND induced gastric ulceration. These findings establish that a combination of IND + JUG may serve as a promising treatment regimen for colon cancer.

Conjugation of cisplatin analogues and cyclooxygenase inhibitors to overcome cisplatin resistance

Cyclooxygenase (COX) is an enzyme involved in tumorigenesis and is associated with tumor cell resistance against platinum-based antitumor drugs. Cisplatin analogues were conjugated with COX inhibitors (indomethacin, ibuprofen) to study the synergistic effects that were previously observed in combination treatments. The conjugates ensure concerted transport of both drugs into cells, and subsequent intracellular cleavage enables a dual-action mode. Whereas the platinum(II) complexes showed cytotoxicities similar to those of cisplatin, the platinum(IV) conjugates revealed highly increased cytotoxic activities and were able to completely overcome cisplatin-related resistance. Although some of the complexes are potent COX inhibitors, the conjugates appear to execute their cytotoxic action via COX-independent mechanisms. Instead, the increased lipophilicity and kinetic inertness of the conjugates seem to facilitate cellular accumulation of the platinum drugs and thus improve the efficacy of the antitumor agents. These conjugates are important tools for the elucidation of the direct influence of COX inhibitors on platinum-based anticancer drugs in tumor cells.

Indomethacin suppresses the growth of colon 26, Meth-A and FM3A tumors in mice by reducing the prostaglandin E2 content and telomerase activity in tumor tissues

The antitumor effect of indomethacin on Colon 26, Meth-A and FM3A tumors was investigated in mice. The prostaglandin E2 content in tumor tissues was assayed to find out if indomethacin acts on tumors, and the telomerase activity in tumors and somatic tissues (testis, liver, spleen and colon) was also monitored during indomethacin treatment. Growth of Colon 26, Meth-A and FM3A tumors was significantly (P < 0.001-0.05) suppressed by indomethacin compared to the untreated controls. The prostaglandin E2 content in the three tumors was markedly (P < 0.001) reduced by indomethacin. Telomerase activity in Colon 26 and FM3A tumors was significantly (P < 0.001) lower than that of untreated tumors (80% and 45% decrease versus the controls, respectively), and the activity in Meth-A tumor was slightly decreased (10% decrease versus the control) by indomethacin. Telomerase activity in the somatic tissues was not significantly affected by indomethacin. In summary, this study shows the effectiveness of indomethacin as an antitumor agent against three types of tumors, and suggests that indomethacin affects telomerase activity in tumors in vivo.

Effectiveness of indomethacin as an antitumor agent in Colon 26-bearing conventional and nude mice, and telomerase activity in the tumors

The antitumor effect of indomethacin on Colon 26 tumor was investigated in conventional (CDF1) and nude mice (BALB/c nu/nu), and the telomerase activity in the tumor tissues treated with indomethacin was monitored. Growth of Colon 26 tumor was significantly suppressed with indomethacin treatment compared to the controls both in conventional and nude mice. And telomerase activity in the tumor tissues noticeably declined in contrast to normal somatic tissues (testis, liver and colon), which were not affected by indomethacin treatment. We also showed that indomethacin can suppress tumor growth in association with a preferential decrease in telomerase activity in tumor tissues both in conventional and nude mice to the same extent. This study suggests a method for investigating the mechanism of tumor suppression by indomethacin, and suggests that indomethacin might be useful as a novel agent for human cancer therapy.