Hisanori Miki

Resveratrol induces apoptosis via ROS-triggered autophagy in human colon cancer cells

Resveratrol (Res; 3,4′,5-trihydroxy-trans-stilbene), which is a polyphenol found in grapes, can block cell proliferation and induce growth arrest and/or cell death in several types of cancer cells. However, the precise mechanisms by which Res exerts anticancer effects remain poorly understood. Res blocked both anchorage-dependent and -independent growth of HT-29 and COLO 201 human colon cancer cells in a dose- and time-dependent manner. Annexin V staining and Western blot analysis revealed that Res induced apoptosis accompanied by an increase in Caspase-8 and Caspase-3 cleavage. In HT-29 cells, Res caused autophagy as characterized by the appearance of autophagic vacuoles by electron microscopy and elevation of microtubule-associated protein 1 light chain 3 (LC3)-II by immunoblotting, which was associated with the punctuate pattern of LC3 detected by fluorescein microscopy. Inhibition of Res-induced autophagy by the autophagy inhibitor 3-methyladenine caused a significant decrease in apoptosis accompanied by decreased cleavage of Casapse-8 and Caspase-3, indicating that Res-induced autophagy was cytotoxic. However, inhibition of Res-induced apoptosis by the pan-caspase inhibitor Z-VAD(OMe)-FMK did not decrease autophagy but elevated LC3-II levels. Interestingly, Res increased the intracellular reactive oxygen species (ROS) level, which correlated to the induction of Casapse-8 and Caspase-3 cleavage and the elevation of LC3-II; treatment with ROS scavenger N-acetyl cysteine diminished this effect. Therefore, the effect of Res on the induction of apoptosis via autophagy is mediated through ROS in human colon cancer cells.

Requirement of p38 MAPK for a cell-death pathway triggered by vorinostat in MDA-MB-231 human breast cancer cells

Vorinostat is a histone deacetylase inhibitor that effectively suppresses cancer-cell proliferation by inducing cell-cycle arrest and/or apoptosis. We now show the involvement of p38 mitogen-activated protein kinase (MAPK) in the regulation of vorinostat-induced apoptosis in MDA-MB-231 human breast cancer cells. Vorinostat induced the hyperacetylation of histone H3, which correlated to apoptosis induction. Vorinostat-induced apoptosis occurred in parallel with the phosphorylation of p38 MAPK and the dephosphorylation of extracellular signal-regulated kinases 1 and 2 (ERK1/2). Knockdown of p38 MAPK prominently abrogated apoptosis induction and was accompanied by decreased caspase-3 cleavage. These findings support the notion that the activation of the p38 MAPK pathway followed by caspase-3 cleavage is responsible for vorinostat-induced apoptosis in MDA-MB-231 cells.

N -ethyl- N -nitrosourea induces retinal photoreceptor damage in adult rats.

Seven-week-old male Lewis rats received a single intraperitoneal injection of N-ethyl-N-nitrosourea (ENU) (100, 200, 400 or 600 mg/kg), and retinal damage was evaluated 7 days after the treatment. Sequential morphological features of the retina and retinal DNA damage, as determined by a TUNEL assay and phospho-histone H2A.X (γ-H2AX), were analyzed 3, 6, 12, 24 and 72 hr, 7 days, and/or 30 days after 400 mg/kg ENU treatment. Activation of the nuclear enzyme poly (ADP-ribose) polymerase (PARP) was analyzed immunohistochemically by poly (ADP-ribose) (PAR) expression in response to DNA damage of the retina. All rats that received ≥ 400 mg/kg of ENU developed retinal degeneration characterized by the loss of photoreceptor cells in both the central and peripheral retina within 7 days. In the 400 mg/kg ENU-treated rats, TUNEL-positive signals were only located in the photoreceptor cells and peaked 24 hr after ENU treatment. The γ-H2AX signals in inner retinal cells appeared at 24 hr and peaked at 72 hr after ENU treatment, and the PAR signals selectively located in the photoreceptor cell nuclei appeared at 12 hr and peaked at 24 hr after ENU treatment. However, degeneration was restricted to photoreceptor cells, and no degenerative changes in inner retinal cells were seen at any time points. Retinal thickness and the photoreceptor cell ratio in the central and peripheral retina were significantly decreased, and the retinal damage ratio was significantly increased 7 days after ENU treatment. In conclusion, ENU induced retinal degeneration in adult rats that was characterized by photoreceptor cell apoptosis through PARP activity.

Two cases of malignant peritoneal mesothelioma without asbestos exposure: cytologic and immunohistochemical features

Approximately half a century has passed since asbestos was first reported to be the main cause of malignant mesothelioma; yet the incidence of this disease continues to increase worldwide. Twenty percent of cases occur without prior asbestos exposure, and in these patients, malignant peritoneal mesothelioma is more common than malignant pleural mesothelioma. Here, we report the cytomorphologic and immunohistochemical features of 2 cases of malignant peritoneal mesothelioma where there was no history of asbestos exposure. Ascitic cytology showed that most cells were isolated and that clusters were rarely observed, but the findings were consistent with malignant mesothelioma in both cases. Immunohistochemical analysis for epithelial membrane antigen, calretinin, vimentin, β-catenin, melan-A, glucose transporter-1, cytokeratin CAM5.2, Wilms tumor antigen-1, D2-40, CD146, progesterone receptor, estrogen receptor, and cytokeratin 5/6 was indicative of malignant mesothelioma. In malignant mesothelioma without prior asbestos exposure, the etiology and prognostic significance is still unclear. Further study is needed to clarify this point.

Retinal Degeneration Induced in Adult Mice by a Single Intraperitoneal Injection of N-Ethyl-N-Nitrosourea:

Seven-week-old female BALB/c mice received a single intraperitoneal injection of N-ethyl-N-nitrosourea (ENU) (50, 100, 200, 400, or 600 mg/kg), and retinal damage was evaluated after 7 days. Sequential morphological features of the retina and retinal apoptosis, as determined by the TUNEL assay, were analyzed 6, 12, 24, and 72 hr and 7 days after treatment with 600 mg/kg of ENU. Moreover, older mice (25 to 34 weeks of age) received an intraperitoneal injection of 600 mg/kg ENU and were sacrificed 7 days later. All animals were necropsied, and both eyes were examined histopathologically. Two of the 5 mice that received 600 mg/kg ENU died during the experimental period. Histopathologically, all mice that received 600 mg/kg of ENU experienced retinal degeneration characterized by the loss of photoreceptor cells (disappearance of the outer nuclear layer and photoreceptor layer) in both the central and peripheral retina within 7 days. One of 5 mice treated with 400 mg/kg ENU exhibited retinal damage that was restricted to the central retina. Older mice treated with 600 mg/kg ENU exhibited retinal damage that was similar to the retinal damage in younger mice. In the 600 mg/kg ENU-treated mice, TUNEL-positive photoreceptor cells peaked 72 hr after ENU treatment. Retinal thickness and the photoreceptor cell ratio in the central and peripheral retina were significantly decreased, and the retinal damage ratio was significantly increased 7 days after treatment. In conclusion, ENU induces retinal degeneration in adult mice that is characterized by photoreceptor cell apoptosis.

A case report of lipid-rich carcinoma of the breast including histological characteristics and intrinsic subtype profile.

A 57-year-old Japanese woman with schizophrenia, who had received long-term treatment with neuroleptics, noticed a painless, pea-sized lump in her right breast. She was admitted to our hospital and a malignant tumor was diagnosed. The patient underwent a conservative radical mastectomy (Patey’s operation). The excised tumor measured 2.0 × 1.2 × 1.1 cm in diameter, and its cut surface was grayish-white. Histologically, tumor cells with clear to foamy cytoplasm were invariably Oil Red O-positive and periodic acid Schiff-negative with or without diastase digestion. The tumor was diagnosed as a lipid-rich carcinoma accompanied by an in situ component. Neuroleptics increase serum prolactin levels by interfering with dopaminergic inhibition of prolactin secretion. Immunohistochemical analysis revealed that, although prolactin was not detected, the tumor cells expressed prolactin receptor, indicating prolactin as the genesis of this neoplasm. In immunohistochemical intrinsic subtype analysis, the tumor was negative for estrogen receptor, progesterone receptor, human epidermal growth factor receptor 1 and 2, and basal cytokeratins (CK5, CK6, and CK14), indicating an unclassified (all-marker negative) subtype. Axillary lymph nodes were free of metastasis (stage I), and the patient has been well for 20 years without any evidence of recurrence.

Spontaneously occurring intracranial lipomatous hamartoma in a young BALB/c mouse and a literature review.

An intracranial lipomatous hamartoma was found in the third ventricle of a 7-week-old female BALB/cAnNCrlCrlj mouse. The nodule was composed of mature white adipose cells, which contained one large fat droplet, and there was no evidence of cytological atypia. The brain parenchyma at the retrosplenial granular cortex and the hippocampus in the cerebrum were slightly compressed, and the choroid plexus was dislocated downward. Scattered capillary vessels penetrated the nodule from the surrounding tissue. Based on these findings, the lesion was diagnosed as a lipomatous hamartoma that occurred from the roof of the third ventricle. This extremely rare tumor-like nodule represents an overgrowth of the mature adipocyte population as a malformation rather than a true neoplasm.

A Case Report of Surgical Resections with Local and Systemic Chemotherapy for Three Recurrences of Colon Cancer Occurring Ten Years after Colectomy

A 56-year-old Japanese woman who underwent a curative resection of ascending colon cancer at 43 years of age was found to have a tumor in her lower left abdominal cavity by computed tomography at 53 years of age. The tumor in the omentum was resected and identified as an adenocarcinoma compatible with metastasis from the primary ascending colon cancer. Although the patient received adjuvant chemotherapy with tegafur uracil and calcium folinate, liver metastasis was detected 9 months after the first recurrence. A segmentectomy and hepatectomy was performed, and histopathological findings indicated metastasis from the primary colon cancer. A third recurrence was detected in the right abdominal cavity 7 months after the second surgery. The patient received 5 cycles of combination chemotherapy consisting of folinic acid, fluorouracil and irinotecan before the third operation. The metastatic tumor resection together with intraperitoneal chemotherapy was performed, and histopathological findings indicated metastasis from the primary colon cancer. After the third surgery, the patient received adjuvant chemotherapy consisting of 5 cycles of folinic acid, fluorouracil and oxaliplatin. The patient is well with no evidence of recurrence 12 months after the third recurrence. This case suggests that colon cancer can be dormant for over 10 years and that long-term follow-up is required after curative resection. Aggressive local as well as systemic chemotherapy may be required for the management of colon cancer recurrence.