[Development of "Patient Friendly Formulations" to Counter the Side Effects of Cancer Chemotherapy]

　Anticancer drug-induced stomatitis develops in 30% to 40% of cancer patients undergoing chemotherapy. However, medications for this condition are not commercially available in Japan. The "hospital formulation" is a customized medicine which hospital pharmacists prepare when doctors cannot carry out the medical therapy most suitable for a patient using commercial medicines. However, as the duties of pharmacists increase, use of the "hospital fomulation" decreases. Therefore, development of "hospital fomulations" based on individual evidence has a limit. Irsogladine maleate (IM) is a drug with gastric mucosal protective properties. IM increases intracellular cAMP levels in the gastric mucosa and activates communication between cells. It has been reported that the oral administration of IM reduces the incidence of 5-FU-based chemotherapy-induced stomatitis. However, there have been no reports on the effect of the direct use of IM in treating stomatitis. Therefore, we studied the development of an IM oral spray for stomatitis treatment, and obtained evidence of a direct effect in an animal experiment using a stomatitis model. Next, rebamipide mouthwash was administered to patients who had stomatitis caused by cancer chemotherapy. The total scores were classified into Grades 0 to 4 and evaluated as a stomatitis evaluation score (SES). When comparing SES and changes in the stomatitis area in patients, gradual reductions in the extent of stomatitis were observed, even during the period when SES did not change. Having patients fill in an observation chart was effective for grasping changes in symptoms in outpatients.

Irsogladine maleate, a gastric mucosal protectant, suppresses intestinal polyp development in Apc-mutant mice

This study aimed to identify gastric mucosal protectants that suppress intestinal tumorigenesis in a mouse model. We chose six gastric mucosal protectants (ecabet sodium hydrate, irsogladine maleate, rebamipide, sofalcone, teprenone and troxipide) and examined their effects on the activity of oxidative stress-related transcriptional factors, including AP-1, NF-jB, NRF2, p53 and STAT3, in Caco-2 cells using a luciferase reporter gene assay. Among the six protectants, irsogladine maleate clearly inhibited NF-jB and AP-1 transcriptional activity. Furthermore, the chemopreventive property of irsogladine maleate was examined in a Min mouse model of familial adenomatous polyposis. Treatment with irsogladine maleate at doses of 5 and 50 ppm significantly reduced the number of intestinal polyps to 69% and 66% of the untreated control value, respectively. In these polyps, mRNA levels of the downstream targets of NF-jB, such as IL-1β and IL-6, were decreased by irsogladine maleate treatment. Moreover, the levels of oxidative stress-related markers, reactive carbonyl species, in the livers of Min mice were clearly decreased following the administration of irsogladine maleate. This study demonstrated that irsogladine maleate suppresses intestinal polyp formation in Min mice partly through the NF-jB signaling pathway, thus reducing oxidative stress.

Irsogladine maleate inhibits Porphyromonas gingivalis-mediated expression of toll-like receptor 2 and interleukin-8 in human gingival epithelial cells

BACKGROUND AND OBJECTIVE

Periodontitis is an infectious disease caused by an interaction between the host and periodontopathogenic bacteria. Regulating the immune response in human gingival epithelial cells (HGEC) may contribute to the prevention of periodontitis. Irsogladine maleate (IM) has previously been shown to regulate inflammation and the cell-cell junctional barrier in HGEC. In addition to these functions, control of bacterial recognition is important for preventing inflammation in periodontal tissue. Innate immunity in gingival epithelium is the first line of defense and plays a crucial role against bacterial challenge. Therefore, the effect of IM on regulating toll-like receptor 2 (TLR2), which is part of the innate immunity, was determined in this study.

MATERIAL AND METHODS

OBA-9, an immortalized human gingival epithelial cell line, and primary cultured HGEC were used in this study. Real-time PCR and western blotting were performed in OBA-9 or HGEC stimulated with whole cells of Porphyromonas gingivalis or with lipopolysaccharide (LPS) derived from P. gingivalis (PgLPS) in the presence or absence of IM to determine expression of TLR2 mRNA and production of TLR2 protein. Small interfering RNA (siRNA) against TLR2 was transfected into OBA-9 to clarify the association between the induction of TLR2 and interleukin-8 (IL-8) production.

RESULTS

The addition of IM into P. gingivalis or PgLPS-induced OBA-9 suppressed IL-8 production (p < 0.01). The addition of IM also abolished the induction of TLR2 by P. gingivalis or PgLPS in OBA-9 and primary cultured HGEC (p < 0.01). The suppressive effect of IM on the induction of TLR2 was also confirmed by immunohistostaining. Stimulation with peptidoglycan, a specific ligand for TLR2, suppressed the expression of toll-like receptor 4 (TLR4) mRNA in the presence of IM (p < 0.01). However, LPS derived from Escherichia coli, a ligand for TLR4, did not induce the expression of TLR2 mRNA. The PgLPS-induced expression of TLR4 mRNA was abolished by IM. Knockdown of TLR2 by siRNA transfection resulted in a weaker response of induction of IL8 mRNA in P. gingivalis or PgLPS-stimulated OBA-9.

CONCLUSION

These results suggest that IM suppresses the induction of IL-8 production by regulating increased levels of TLR2.

Suppressive effect of irsogladine maleate on diethylnitrosamine-initiated and phenobarbital-promoted hepatocarcinogenesis in male F344 rats

Modifying effects of irsogladine maleate (IRG) on diethylnitrosamine (DEN)-induced hepatocarcinogenesis were examined in male F344 rats. Six-week-old rats were divided into 8 groups. Groups 1 through 4 were given a single i.p. injection of DEN (200 mg/kg body weight) at the start of the experiment, whereas groups 5 through 8 received a single i.p. injection of saline as the vehicle treatment. Groups 1 and 8 were kept on the basal diet and distilled water throughout the experiment (36 weeks). Groups 2 and 7 were exposed to 500 ppm phenobarbital (PB) in the drinking water, starting one week after the carcinogen or vehicle treatment. Groups 3 and 5 were fed the diet mixed with 125 ppm IRG from one week after DEN or vehicle treatment. Groups 4 and 6 were given 125 ppm IRG-containing diet and drinking water with 500 ppm PB after the carcinogen or vehicle treatment. Liver neoplasms developed in groups 1 (1/15 rats, 7%) and 2 (14/14 rats, 100%). However, no liver tumors were found in rats of groups 3 through 8. Incidence and average number of liver neoplasms in group 4 (0/14 rats, 0%) were less than those in group 2 (P < 0.0001). The number of glutathione S-transferase placental form (GST-P)-positive liver cell foci in group 3 or 4 was significantly smaller than that in the appropriate control (P < 0.01, P < 0.001, respectively). The average and unit areas of these foci in group 4 were also significantly smaller than those in group 2 (P < 0.001, P < 0.05, respectively). These results suggest that IRG could be a chemopreventive agent for rat liver carcinogenesis.