Tatsuhiko Shigeto

Clofibric acid, a peroxisome proliferator–activated receptor α ligand, inhibits growth of human ovarian cancer

Recent reports have shown that peroxisome proliferator–activated receptor (PPAR)α ligands reduce growth of some types of malignant tumors and prevent carcinogenesis. In this study, we investigated the inhibitory effect of clofibric acid (CA), a ligand for PPARα on growth of ovarian malignancy, in in vivo and in vitro experiments using OVCAR-3 and DISS cells derived from human ovarian cancer and aimed to elucidate the molecular mechanism of its antitumor effect. CA treatment significantly suppressed the growth of OVCAR-3 tumors xenotransplanted s.c. and significantly prolonged the survival of mice with malignant ascites derived from DISS cells as compared with control. CA also dose-dependently inhibited cell proliferation of cultured cell lines. CA treatment increased the expression of carbonyl reductase (CR), which promotes the conversion of prostaglandin E2 (PGE2) to PGF2α, in implanted OVCAR-3 tumors as well as cultured cells. CA treatment decreased PGE2 level as well as vascular endothelial growth factor (VEGF) amount in both of OVCAR-3–tumor and DISS-derived ascites. Reduced microvessel density and induced apoptosis were found in solid OVCAR-3 tumors treated by CA. Transfection of CR expression vector into mouse ovarian cancer cells showed significant reduction of PGE2 level as well as VEGF expression. These results indicate that CA produces potent antitumor effects against ovarian cancer in conjunction with a reduction of angiogenesis and induction of apoptosis. We conclude that CA could be an effective agent in ovarian cancer and should be tested alone and in combination with other anticancer drugs. [Mol Cancer Ther 2007;6(4):1379–86]

Inhibitory effect of meloxicam, a selective cyclooxygenase-2 inhibitor, and ciglitazone, a peroxisome proliferator-activated receptor gamma ligand, on the growth of human ovarian cancers.

It was recently reported that high expression of peroxisome proliferator‐activated receptor γ (PPARγ) and low expression of cyclooxygenase‐2 (COX‐2) might be involved in the inhibition of ovarian tumor progression and confirmed that PPARγ activation could suppress COX‐2 expression via the nuclear factor‐κB pathway in ovarian cancer cells.

Anti-Tumor Effect of Non-Steroidal Anti-Inflammatory Drugs on Human Ovarian Cancers

Many reports have demonstrated that non-steroidal anti-inflammatory drugs (NSAIDs) suppress malignant transformation and tumor growth, and some NSAIDs are expected to be new anti-cancer agents. In this study, we examined the anti-tumor effects of the non-specific cyclooxygenase (COX) inhibitors aspirin and piroxicam, and the selective COX-2 inhibitor meloxicam on xenotransplanted ovarian cancer. Tumor growth and survival were compared in female nu/nu mice, xenografted with subcutaneous OVCAR-3 tumors or with intraperitoneal DISS tumors and treated with aspirin (200 ppm in diet, everyday), piroxicam (150 ppm in diet, everyday) or meloxicam (162 ppm in diet, everyday). Al, of the agents tested significantly suppressed the growth of OVCAR-3 tumors xenotransplanted subcutaneously as compared to the control. There was a significant difference in inhibition of OVCAR-3 tumor growth between meloxicam and aspirin treatment. Meloxicam and piroxicam treatment significantly prolonged survival of mice with malignant ascites derived from DISS cells as compared to control and aspirin treatment. Mice treated with meloxicam survived significantly longer than those treated with piroxicam. There was no significant difference in survival between control and aspirin treatment. Necropsy revealed that one of the 6 cancer-bearing mice treated with piroxicam suffered from stomach perforation. These results indicate that a selective COX-2 inhibitor produces greater anti-tumor effect against ovarian cancer than a nonselective COX inhibitor and that meloxicam may have a potential of leading to a novel therapeutic strategy against ovarian cancer.

Decreased ARID1A expression is correlated with chemoresistance in epithelial ovarian cancer

Objective Loss of ARID1A is related to oncogenic transformation of ovarian clear cell adenocarcinoma. The present study was conducted in epithelial ovarian cancer of all tissue types to investigate whether an increased or decreased expression level of ARID1A can be a prognostic factor for ovarian cancer or can influence the sensitivity to anticancer drugs. Methods The expression level of ARID1A was investigated in 111 patients with epithelial ovarian cancer who received initial treatment at the Hirosaki University Hospital between 2006 and 2011. The expression level of ARID1A was immunohistochemically graded using staining scores, which were calculated by multiplying the staining intensity of the nuclei by the stain-positive area. Results The level of ARID1A was significantly lower in clear cell adenocarcinoma than in other histologic types. Among the patients with stage III, IV cancer (n=46), the level of ARID1A was significantly lower (p=0.026) in patients who did not achieve complete response (CR; n=12) than in patients who achieved CR (n=34). The level of ARID1A was relatively lower (p=0.07) in patients who relapsed after achieving CR (n=21) than in patients who did not relapse (n=13). When the staining score of 0 was defined as ARID1A-negative and other staining scores were defined as ARID1A-positive, there was significant difference in progression-free survival between ARID1A-negative (n=11) and ARID1A-positive (n=35) patients in stage III, IV disease. Conclusion The result suggests that decreased ARID1A expression is correlated with chemoresistance and may be a predictive factor for the risk of relapse of advanced cancer after achieving CR.

A Case of Uterine Leiomyoma with Intravenous Leiomyomatosis—Histological Investigation of the Pathological Condition—

Intravenous leiomyomatosis (IVL) is generally defined as a histologically benign leiomyoma derived from a uterine myoma or intrauterine venous wall that has grown and extended intravenously. We here report on a single case of IVL, and investigate its pathological genesis. Regarding the part of the myoma extending to the vessel lumen, observations found the myoma to be pushing into the vessel. Immunostaining with CD34 antibody gave an image of the area where the myoma pushed into the vessel, showing CD34-positive vessel endothelium cells folded back into a layer covering the myoma, and continuing to line of the surface of the myoma within the vessel. Early pathological genesis of IVL was clarified for the first time that the tumor did not invade the vessel by breaking the venous wall, but rather advanced by stretching the vascular wall and progressing into the vein like a polyp, covered in endothelium cells.

The prophylactic effects of a traditional Japanese medicine, goshajinkigan, on paclitaxel-induced peripheral neuropathy and its mechanism of action

BackgroundThis study aimed to evaluate the prophylactic effect of goshajinkigan (GJG) on paclitaxel (PTX)-induced neuropathy and to elucidate the mechanism of action.ResultsThere was a time-dependent irreversible decrease in pain threshold in PTX group. In PTX/GJG group, pain threshold showed changes in the same level as control. Electron microscope showed that although the ganglion cells of control and PTX/GJG groups were normal, degeneration of the nucleus and swelling of the mitochondria were observed in PTX group. Expression of transient receptor potential vanilloid 4 (TRPV4) gene in PTX group significantly increased compared with that in control and PTX/GJG groups. In TRPV4 knock-out mice, no PTX-induced hyperalgesia was observed, and there was no significant difference in pain threshold between the 3 groups.ConclusionsThese results showed that PTX induced hyperalgesia by enhancing TRPV4 expression, and suggested that GJG might alleviate hyperalgesia by preventing degeneration of the ganglion cells and suppressing TRPV4 expression.

Decreased expression of carbonyl reductase 1 promotes ovarian cancer growth and proliferation

Carbonyl reductase 1 (CBR1) expression level is related to tumor progression. Decreased CBR1 expression is associated with poor prognosis in ovarian cancer. We investigated the relationship between CBR1 expression level and malignant potential of ovarian cancer. OVCAR‑3 cells overexpressing CBR1 or knocked down for CBR1 were obtained by transfecting CBR1 plasmid DNA (pDNA) or small interfering RNA (siRNA) by electroporation. In vitro cell proliferation and invasion were compared between the two cell types. Subcutaneous CBR1‑overexpressed OVCAR‑3 cells (n=10) and wild‑type ones (n=5) were injected into nude mice. The CBR1 siRNA was then injected twice a week into five of the 10 CBR1‑overexpressed OVCAR‑3 tumors. Tumor growth and metastatic behavior were observed 3 weeks after cell transplantation. Cell proliferation significantly decreased in CBR1‑overexpressed cells as compared to the control, whereas cell proliferation and invasion significantly increased in CBR1‑suppressed cells as compared to the control. The size of the CBR1 siRNA‑injected tumors (n=5) increased significantly as compared to the other two groups (n=5 for each group). The number of metastatic foci in the lungs was significantly higher in mice injected with CBR1 siRNA (7.0±2.0) compared to CBR1‑overexpressed and wild‑type tumors (0 and 2.0±2.0, respectively). Western blot analysis showed that, while vascular endothelial growth factor (VEGF)‑C expression was stable in the CBR1‑siRNA‑injected tumors, E‑cadherin expression was decreased, whereas matrix metalloproteinase (MMP)‑9 was increased in CBR1‑siRNA‑injected tumors compared to the other two groups. These results showed that CBR1 decreases promoted tumor proliferation and growth as well as invasion and metastasis, suggesting that CBR1 has potential to become a new candidate for molecular targeting therapy.

A Strategy Using Photodynamic Therapy and Clofibric Acid to Treat Peritoneal Dissemination of Ovarian Cancer.

BACKGROUND The current study examined the effectiveness of concurrent therapy using photodynamic therapy (PDT) and clofibric acid (CA) to treat peritoneal carcinomatosis resulting from ovarian cancer. MATERIALS AND METHODS Nude rats were used to create a model of peritoneal carcinomatosis resulting from ovarian cancer and the effectiveness of PDT with 5-aminolevulinic acid methyl ester hydrochloride (methyl-ALA-PDT) was determined. The survival time of rats receiving that therapy was compared to the survival time of a control group. Rats with peritoneal carcinomatosis resulting from ovarian cancer were divided into 3 groups: a group that received debulking surgery (DS) alone, a group that received DS+methyl-ALA-PDT, and a group that received DS+methyl-ALA-PDT+CA. The survival time of the 3 groups was compared. Protoporphyrin, a metabolite of methyl-ALA, produces a photochemical action when activated by light. The level of protoporphyrin (the concentration) that reached organs in the abdomen was measured with HPLC. RESULTS Rats receiving methyl- ALA-PDT had a significantly longer survival time compared to the controls. Rats with peritoneal carcinomatosis that received DS+methyl-ALA-PDT+CA had a significantly longer survival time compared to the rats that received DS alone. Some of the rats that received concurrent therapy survived for a prolonged period. Protoporphyrin was highly concentrated in peritoneal metastases, but only small amounts reached major organs in the abdomen. PDT was not found to result in necrosis in the intestines. CONCLUSIONS The results indicated that concurrent therapy consisting of PDT with methyl-ALA and CA is effective at treating peritoneal carcinomatosis resulting from ovarian cancer without damaging organs.

The level of RECQL1 expression is a prognostic factor for epithelial ovarian cancer

BackgroundThe human RECQ DNA helicase family is involved in genomic stability. Gene mutations of RECQL2, RECQL3, and RECQL4 are associated with genetic disorders and induce early aging and carcinogenesis. Although previous studies have reported that the level of RECQL1 expression is correlated with the prognosis of some of malignancies, the function of RECQL1 is not yet clarified. The present study aimed to examine the relationship between prognosis and the level of RECQL1 expression in epithelial ovarian cancer (EOC), and to identify the role of RECQL1 in EOC cells.MethodsThe level of RECQL1 expression was determined immunohistochemically in 111 patients with EOC who received initial treatment at Hirosaki University hospital between 2006 and 2011. Effects of RECQL1 on cell growth or apoptosis were examined in vitro using wild-type and OVCAR-3 cells (RECQL1(+) cells) and similar cells transfected with RECQL1 siRNA transfected (RECQL1(−) cells).ResultsThe level of RECQL1 expression was not related to histological type, clinical stage, or retroperitoneal lymph node metastasis, but the expression level was significantly higher (P = 0.002) in patients with recurrence than those without recurrence, and progression-free survival and complete response rate to chemotherapy were also improved in patients with RECQL1-low expression (n = 39) stage III/IV EOC (P = 0.02 and P <0.05 vs RECQL1-high expression patients (n = ), respectively). A cell proliferation and colony formation assays revealed significantly less growth of RECQL1(−) cells compared to RECQL1(+) cells. A flow cytometry using annexin V -FITC and propidium iodide (PI) staining revealed a significant increase in apoptotic RECQL1(−) cells. Cell cycle analysis showed a significantly greater distribution in subG1 phase indicating apoptotic cells in RECQL1(−) cells than in RECQL1(+) cells.ConclusionsThese results suggest that RECQL1 is a prognostic factor for EOC and that RECQL1 contributes to potential malignancy by inhibiting apoptosis.

Differences in the sensitivity of ovarian cancer to photodynamic therapy and the mechanisms for those differences

Protoporphyrin IX (PpIX) levels are crucial to the antitumor action of photodynamic therapy (PDT). In the present study, the underling molecular mechanisms for the variation in PpIX levels in ovarian cancer cells were investigated. Five ovarian cancer cell lines were subcutaneously grafted onto the backs of nude mice. Once tumors had developed, 5-aminolevulinic acid methyl ester hydrochloride (methyl-ALA) was administered intraperitoneally and the tumor was irradiated twice/week. PpIX levels in the tumor were assayed using high-performance liquid chromatography. Enzymes involved in heme synthesis and degradation were screened using a microarray technique. Expression of the glutathione transferase Omega-1 (GSTO1) gene involved in the conversion of PpIX into heme in cells was quantified using the reverse transcription-quantitative polymerase chain reaction. In HTOA, HRA and DISS cells, PDT resulted in significant tumor shrinkage in comparison with the controls. In MCAS and TOV21G cells, no significant alterations in tumor growth were identified compared with the untreated cells. PpIX levels increased significantly in HTOA, DISS and HRA cells compared with in MCAS and TOV21G cells. A comparison of genetic profiles using PDT-sensitive DISS cells and PDT-resistant MCAS cells indicated that MCAS cells exhibited significantly increased levels of δ-aminolevulinate synthase (a rate-limiting enzyme in heme synthesis), heme oxygenase 2 (an enzyme that degrades heme into biliverdin), and biliverdin reductase B (an enzyme that reduces biliverdin into bilirubin) in comparison with DISS cells. The level of GSTO1 expression in HTOA, HRA and DISS cells was ~2.5-fold that in MCAS and TOV21G cells. Sensitivity to PDT is related to PpIX levels in cells. The results of the present study suggested that PpIX tends not to accumulate in PDT-resistant cells despite active heme synthesis and degradation, and that high levels of GSTO1 expression are associated with increased sensitivity to PDT.