Shuji Nakano

Gefitinib, a selective EGFR tyrosine kinase inhibitor, induces apoptosis through activation of Bax in human gallbladder adenocarcinoma cells†

Although gefitinib, a selective inhibitor of epidermal growth factor receptor (EGFR) tyrosine kinase, has been clinically demonstrated to be effective for certain cancer cell types, the molecular mechanisms of the anti‐tumor activity have not been fully elucidated. In this study, we investigated the mechanism of gefitinib‐induced growth inhibition and apoptosis in HAG‐1 human gallbladder adenocarcinoma cells. Treatment of gefitinib at a dose of 1 µM resulted in a significant growth inhibition, and the cell number irreversibly declined after 72‐h incubation, with a progressive expansion of apoptotic cell population over 120‐h. Following 2‐h treatment, gefitinib significantly inhibited EGFR autophosphorylation and subsequent downstream signaling pathway through Erk and Akt, and induced accumulation of cells in the G0/G1 phase of the cell cycle at 24‐h, accompanied by a concomitant increase in p21 transcript and increased expression of p27. Gefitinib did not affect the amount of total and phosphorylated p53 at serine 15, but upregulated the expression of total Bax, with subsequent increase in p18 Bax, an active form of Bax. The expression of Bcl‐2 and Bad was unchanged. An increase in gefitinib‐induced expression of total Bax might be due to the decreased degradation of Bax, because the level of Bax mRNA has not been altered by gefitinib treatment. Gefitinib promoted the cleavage of full‐length p21 Bax into p18 Bax in mitochondrial‐enriched fraction, a characteristic feature of Bax activation toward apoptosis. Moreover, blockade of Bax by using anti‐Bax small interfering double stranded RNA (siRNA) significantly reduced gefitinib‐induced apoptosis. Taken together, these data suggest a critical role of p18 Bax in gefitinib‐induced apoptosis. J. Cell. Biochem. 97: 724–734, 2006.

B cell activation regulates exosomal HLA production

Exosomes are nanovesicles produced constitutively and inducibly by several types of cells. They are generated as intraluminal vesicles of multivesicular bodies and express MHC and several endosomal/lysosomal proteins. In spite of their potential role in cellular immunity, the regulatory mechanisms of exosome production are largely unknown. In this study, we have established a novel ELISA system to quantify exosomal HLA using a combination of anti‐HLA class I and anti‐HLA‐DR mAb. We found that exosomal HLA production of B cells was enhanced by contact with CD4+ T cells. Neutralizing anti‐CD154 (CD40L) mAb inhibited this effect, and a soluble CD40L significantly increased production of exosomal HLA in B cells. In addition, B cell stimulation via BCR and TLR9 enhanced their production while IL‐4 stimulation alone failed to do so. Strikingly, an inhibitor of the classical NF‐κB pathway drastically inhibited exosomal HLA production in stimulated B cells, indicating that the classical NF‐κB pathway is critical for exosomal HLA production in B cells. Together, these findings suggest a pivotal role of B cell activation in exosomal HLA production in vivo.

Polymerase chain reaction detection of bacterial 16S rRNA gene in human blood

Bacterial 16S ribosomal RNA genes (rDNA) were detected in blood samples from two healthy individuals by PCR under conditions involving 30 cycles that did not produce any visible products from negative control saline. Even from control samples, PCR involving 35–40 cycles yielded visible bands. Major clones detected in the blood samples, but not in control, were the Aquabacterium subgroup, Stenotrophomonas subgroup, Budvicia subgroup, Serratia subgroup, Bacillus subgroup and Flavobacteria subgroup. No clone was located within the bacteroides‐clostridium‐lactobacillus cluster, which is indigenous to gastrointestinal flora.

Oxaliplatin-induced allergic reaction in patients with colorectal cancer in Japan

BackgroundOxaliplatin is a platinum compound that is clinically effective for colorectal cancer (CRC), in combination with 5-fluorouracil (5-FU) and leucovorin (LV), and it is widely used for metastatic disease and for the adjuvant treatment of stage III CRC. With the increasing use of oxaliplatin in Japan, serious adverse events have been experienced other than hematologic and neurologic toxicities.MethodsIn order to clarify the clinical features of allergic reactions to oxaliplatin, we retrospectively investigated CRC patients who had received oxaliplatin-based chemotherapies.ResultsOne hundred and twenty-five CRC patients who had been treated with FOLFOX regimens (containing oxaliplatin, 5-FU, and LV) were examined, and 21 patients (17%) were found to have developed allergic reactions. Sixteen patients (13%) had grade 1/2 adverse events, classified according to the common terminology criteria for adverse events (CTC-AE) version 3.0 and 5 (4%) had grade 3/4 adverse events. The allergic reaction appeared after a median number of nine cycles (range, 2–15 cycles). Previous chemotherapy included 5-FU/LV, CPT-11, and S-1. All of the patients with allergic reactions recovered completely when treated with antiallergy drugs. Oxaliplatin was reintroduced in 11 patients, with the use of prophylactic agents; allergic reaction to the reintroduction was not observed in 8 patients and grade 1/2 allergic reactions developed in 3 patients. No correlation was identified between allergic reaction and patients’ background characteristics such as sex, history of allergy, and profile of other adverse events.ConclusionAllergic reactions to oxaliplatin remain an important issue for patients being able to safely continue effective chemotherapies; further analysis will be needed to establish methods for the prediction and prophylaxis of such reactions.

Mechanism of the Anticancer Effect of Lycopene (Tetraterpenoids)

Increasing evidence suggests that lycopene, a major carotenoid detected in human plasma, may be preventive against the formation and the development of different types of human cancers including prostate, breast, and lung cancer. Experimental studies demonstrated that lycopene inhibits the growth of various cancer cells of different organs and prevent chemically induced carcinogenesis in animal models. Although the excellent antioxidant property of lycopene is most likely the basis for its preventive role toward cancer, the direct anticancer activities of lycopene through multiple mechanisms are disclosed, including regulation of growth factor signaling, cell cycle arrest and/or apoptosis induction, and changes in antioxidant and phase II detoxifying enzymes. The anti-inflammatory activity of lycopene is also considered as an important determinant that suppresses the promotion and progression of carcinogenesis. Moreover, lycopene inhibits cell invasion, angiogenesis, and metastasis. Importantly, those activities have been shown to be exhibited at the physiologically attainable concentration in humans. Although the preclinical data strongly suggest an antitumor activity of lycopene, a number of epidemiological and intervention studies indicate that there is still no clear clinical evidence that supports its use for the prevention of those cancers. More well controlled clinical intervention trials are needed to further clarify the exact role of lycopene in the cancer prevention. Nonetheless, because of its multiple tumor-inhibitory activities, lycopene still remains to be an attractive and promising carotenoid that will potentially contribute to the prevention and treatment of human cancers. This chapter reviews data on the cancer preventive activities of lycopene, possible mechanisms involved, and the relationship between lycopene consumption and human cancer risk.

Phase I/II study of a 3‐week cycle of irinotecan and S‐1 in patients with advanced colorectal cancer

The combination of an oral fluoropyrimidine derivative, S‐1, and irinotecan is expected to be a promising regimen for advanced colorectal cancer. This study was performed to determine the maximum tolerated dose (MTD) and recommended dose (RD) of irinotecan combined with S‐1 in a 3‐week cycle regimen and to observe the safety and efficacy for patients with previously untreated advanced colorectal cancer. Eighty milligrams per m2 of S‐1 was given orally for 14 consecutive days and escalated doses of irinotecan were administered on days 1 and 8 every 3 weeks in the phase I trial. Forty patients were treated at the RD during the phase II trial. Forty‐three patients were enrolled between February 2005 and March 2007. The dose‐limiting toxicity was diarrhea and abdominal pain. The MTD of irinotecan was 100 mg/m2 and the RD was determined to be 80 mg/m2 of irinotecan combined with 80 mg/m2 of S‐1. The phase II trial showed that 22 of 40 patients achieved a complete or partial response and eight had stable disease. The overall response rate was 55.0%. The median progression‐free survival time and median survival time were 6.7 and 21 months, respectively. There were no treatment‐related deaths. The main toxicities were leukopenia, neutropenia, anorexia and diarrhea. This study suggests the combination of irinotecan and S‐1 repeated every 3 weeks is tolerable and effective for patients with previously untreated advanced colorectal cancer. (Cancer Sci 2010; 101: 2591–2595)

Schedule-dependent synergistic interaction between gemcitabine and oxaliplatin in human gallbladder adenocarcinoma cell lines

To define the most effective combination schedule of gemcitabine and oxaliplatin (L-OHP), we investigated the in-vitro interaction between these drugs in a panel of four human gallbladder adenocarcinoma cell lines (HAG-1, GB-d1, NOZ, and G-415). Cytotoxic activity was determined by the WST-1 assay. Different schedules of the two drugs were compared and evaluated for synergism, additivity, or antagonism with a quantitative method based on the median-effect principle of Chou and Talalay. Cell cycle perturbation and apoptosis were evaluated by flow cytometry. Simultaneous and sequential treatments of gemcitabine followed by L-OHP exhibited synergistic effects in all four cell lines, whereas the reverse sequence largely showed an antagonism. Gemcitabine exclusively arrested cells at the G0/G1 phase, and L-OHP at the G2/M phase, as measured by flow cytometric analyses. Apoptosis was most prominent when cells were treated simultaneously or in a sequence gemcitabine followed by L-OHP, producing apoptosis in treated cells (27–30%). In contrast, the reverse sequence yielded only 6–7% induction of apoptosis, the rate being not significantly different from those induced by each drug singly. Moreover, this sequence dependence was further confirmed by the experiment, which compared the number of HAG-1 cells 7 days after these combination schedules. These findings suggest that the interaction of gemcitabine and L-OHP is highly schedule dependent, with the most efficacious interaction observed in either simultaneous combination or in a sequence combination of gemcitabine followed by L-OHP.

Nonmyeloablative allogeneic hematopoietic stem cell transplantation as immunotherapy for pancreatic cancer.

Objective: Advanced unresectable pancreatic cancer has an extremely poor prognosis despite intensive chemotherapy. As a new therapeutic modality, we investigated nonmyeloablative allogeneic hematopoietic stem cell transplantation from a related donor. Methods: Five patients with chemotherapy-resistant pancreatic cancer received allogeneic peripheral blood stem cell transplantation after a conditioning regimen consisting of low-dose total body irradiation and fludarabine. The prophylaxis for graft-versus-host disease consisted of mycophenolate mofetil and cyclosporine. Results: The median age of the 5 patients was 54 years, and the median duration from diagnosis to nonmyeloablative allogeneic hematopoietic stem cell transplantation was 10 months. Three of the 5 patients achieved complete donor chimerism of peripheral T cells, at a median time of day 42. Acute graft-versus-host disease developed in 3 patients: grade 2 in 2 patients and grade 1 in 1. Tumor reduction was observed in 2 patients: 1 patient showed disappearance of the pancreatic tumor, and the other patient showed approximately 20% reduction of the tumor. Marked elevation of tumor necrosis factor &agr; was observed as the tumor regressed. Conclusions: Although advanced pancreatic cancer progresses rapidly, some graft-versus-tumor effects and pivotal role of tumor necrosis factor &agr; were suggested. To obtain the durable response, patient selection and new strategies become important.

Interannual study of spot urine–evaluated sodium excretion in young Japanese women

The authors investigated interannual differences in the sodium excretion levels of young healthy Japanese women as estimated from spot urine analysis at Nakamura Gakuen University from 1995 to 2015. Participants included 4931 women aged 18 to 20 years who were classified into three time periods according to year of health check: first (1995–2001), second (2002–2007), and third (2008–2015). Estimated daily urinary sodium and potassium excretion levels and the sodium to potassium ratio were 120.6±31.9 mmol, 35.2±8.1 mmol, and 3.5±0.9, respectively. Adjusted for body weight, sodium excretion, and potassium excretion significantly decreased in the second and third period compared with the first period (P<.001). Systolic blood pressure also decreased in the same way between time periods (P<.001). Estimated urinary excretion levels of sodium and potassium in young Japanese women have decreased over the past 20 years independently of body weight.

Equol Enhances Apoptosis-inducing Activity of Genistein by Increasing Bax/Bcl-xL Expression Ratio in MCF-7 Human Breast Cancer Cells

ABSTRACT Anticancer activities of soy isoflavones, such as genistein and equol, a bioactive metabolite of daidzein, have been extensively studied because of possible involvement in the prevention of breast cancer. However, their interactions still remain unclear. We investigated here whether cytotoxic activity of genistein was enhanced by equol, using estrogen receptor positive MCF-7, HER2-positive SK-BR-3, and triple-negative MDA-MB-468 cell lines. Although cytotoxicity of genistein did not significantly differ between three subtypes of breast cancer cells, cytotoxic activities of genistein were significantly enhanced in combination with 50 μM equol in MCF-7 cells, but not in SK-BR-3 and MDA-MB-468 cells. In fluorescence activated cell sorting (FACS) analyses, MCF-7 cells were arrested at the G2/M by genistein but at G1/S by equol. Combination treatment arrested cells at G2/M but abolished equol-induced G1 block, indicating an antagonistic activity of genistein against equol in cell-cycle progression. Although apoptosis was not so evident with genistein alone, the combination made a drastic induction of apoptosis, accompanied by the increase of Bax/Bcl-xL expression ratio, without affecting the activities of Akt and mTOR. Taken together, these data suggest that enhancement of genistein activity by equol would be mainly mediated by augmented induction of apoptosis rather than arrest or delay of the cell cycle.