Masaaki Nishitani

Prognostic values of matrix metalloproteinase‐2 and tissue inhibitor of metalloproteinase‐2 expression in bladder cancer

Matrix metalloproteinase‐2 (MMP‐2), which degrades the extracellular matrix or the basement membrane, has an essential role in tumor invasion and metastasis. To evaluate the roles of MMP‐2, its inhibitor (tissue inhibitor of metalloproteinase‐2 [TIMP‐2]), and its activator (membrane‐type matrix metalloproteinase‐1 [MT1‐MMP]) in tumor invasion or as a prognostic factor in patients with bladder carcinoma, the authors investigated the expression of MMP‐2, TIMP‐2, and MT1‐MMP in patients with bladder carcinoma.

Prostate stem cell antigen predicts tumour recurrence in superficial transitional cell carcinoma of the urinary bladder

To evaluate the relationship between prostate stem cell antigen (PSCA) expression level in transitional cell carcinoma (TCC) of the urinary bladder and various clinicopathological features, including stage and grade; and to determine whether PSCA mRNA expression predicts disease recurrence in superficial (not muscle‐invasive) TCC of the bladder.

Expression of angiopoietin‐1 and ‐2, and its clinical significance in human bladder cancer

To investigate the relationship between angiopoietin‐1 and ‐2 expression and the clinicopathological variables and clinical outcome in patients with bladder cancer treated by surgical resection, as both have been recently identified as antagonistic angiogenic factors which regulate tumour growth.

Phase I trial of personalized peptide vaccination for cytokine-refractory metastatic renal cell carcinoma patients

The aim of this clinical trial was to investigate the toxicity and immunological responses of personalized peptide vaccination for cytokine‐refractory metastatic renal cell carcinoma patients. Patients were confirmed to be human leukocyte antigen (HLA)‐A24 or HLA‐A2 positive and had histologically confirmed renal cell carcinoma. Ten patients were enrolled in the present study. The peptides to be administered were determined based on the presence of peptide‐specific cytotoxic T lymphocyte precursors in peripheral blood mononuclear cells (PBMC) and peptide‐specific IgG in the plasma of cancer patients. Patients received subcutaneous injections of four different peptides (3 mg/peptide) every 2 weeks. Vaccinations were well tolerated without any major adverse events. A minimal increase in peptide‐specific interferon‐γ production in postvaccination PBMC was observed, regardless of higher levels of cytotoxic T lymphocyte activity in prevaccination PBMC. In contrast, an increase in peptide‐specific IgG levels of postvaccination (sixth) plasma was observed in the majority of patients. After progression, five patients received interleukin‐2 therapy and continuous vaccination, with survival of 31, 25, 23, 17, and 15 months, but interleukin‐2 did not impede humoral responses boosted by the vaccination. These results encourage further clinical trials of personalized peptide vaccinations. (Cancer Sci 2007; 98: 1965–1968)

Role of phosphatidylinositol-3 kinase/Akt pathway in bladder cancer cell apoptosis induced by tumor necrosis factor-related apoptosis-inducing ligand

TRAIL/Apo2L is a pro‐apoptotic cytokine that is capable of inducing apoptosis in a wide variety of cancer cells but not in normal cells. Among various molecular strategies by which cancer cells evade apoptosis, PI3K/Akt signaling represents a dominant survival pathway. In this report, we investigated the role of PI3K/Akt pathway in TRAIL‐induced apoptotic death in human bladder cancer cells. We observed that RT4 cells had very low level of constitutively active Akt and were sensitive to TRAIL, whereas UM‐UC‐3 and T24 cells had higher levels of constitutively active Akt and were resistant to TRAIL. Downregulation of constitutively active Akt by PI3K inhibitors, wortmannin and LY294002, reversed cellular resistance to TRAIL. However, transfecting constitutively active Akt into RT4 cells increased Akt activity and inhibited TRAIL‐induced apoptosis. These results suggest that elevated Akt activity protects UM‐UC‐3 and T24 cells from TRAIL‐induced apoptosis, and the PI3K/Akt signaling might inhibit apoptotic signals. Thus, the modulation of Akt activity by combining pharmacological drugs or genetic alterations of the Akt expression could induce cellular responsiveness to TRAIL and PI3K/Akt signaling pathway could serve as a novel target for therapeutic intervention in bladder cancer. (Cancer Sci 2006; 97: 1093–1098)

Roles of NKT cells in resistance against infection with Toxoplasma gondii and in expression of heat shock protein 65 in the host macrophages.

We investigated the roles of gamma delta T, NK, and NK1.1(+) T-like (NKT) cells in protective immunity against infection with Toxoplasma gondii. gamma delta T cells, NKT and NK cells, and NK cells in BALB/c mice were depleted by treatment with anti-TCR-gamma delta monoclonal antibody (mAb), anti-interleukin-2 receptor beta chain (IL-2R beta) mAb, and anti-asialoGM1 Ab, respectively, and these mice were infected with T. gondii. Treatment of mice with anti-TCR-gamma delta mAb aggravated toxoplasmosis, while treatment with anti-asialoGM1 Ab had no effects. Treatment with anti-IL-2R beta mAb enhanced the expression of heat shock protein 65 (HSP65) and gamma interferon (IFN-gamma) mRNA, while it inhibited interleukin-4 (IL-4) mRNA expression, ameliorating toxoplasmosis. In addition to NK cells, anti-IL-2R beta mAb eliminated cells expressing IL-2R beta and intermediate levels of CD3 (IL-2R beta(+) CD3(int)). Mice treated with anti-IL-2R beta mAb decreased the number of DX5(+) CD3(int) cells, which are considered to be equivalent to NK1.1(+)T cells in NK1.1 allele-negative strains. IL-2R beta(+) CD3(int) cells isolated from splenic and hepatic lymphoid cells were confirmed to express the TCR-V alpha 14 transcript. The magnitude of HSP65 induction in macrophages correlated with the protective potential against T. gondii infection after treatment with the antibodies, supporting our previous finding that gamma delta T cells play an essential role in the induction of HSP65 in host macrophages. Interestingly, NKT cells suppressed the expression of gamma delta T cell-induced HSP65 and IFN-gamma. Furthermore, depletion of IL-2R beta(+) CD3(int) cells suppressed the IL-4 mRNA expression. These results suggest that NKT cells may be the cells responsible for suppression of protective immunity against T. gondii infection by interfering with the gamma delta T cell-induced HSP65 expression, possibly through the generation of IL-4.

Prognostic significance of Matrix metalloproteinases-2 activation ratio in renal cell carcinoma

Background: Matrix metalloproteinases (MMPs) are a family of zinc‐dependent endopeptidases. MMP‐2 and MMP‐9 have been reported to be closely associated with tumor invasion and metastasis in various human carcinomas.

Role of the Matrix Metalloproteinase and Tissue Inhibitors of Metalloproteinase Families in Noninvasive and Invasive Tumors Transplanted in Mice With Severe Combined Immunodeficiency

OBJECTIVES To elucidate the role of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in human urothelial cancers, we studied gene expressions of MMPs, TIMPs, and membrane-type 1 matrix metalloproteinase (MT1-MMP) in noninvasive or invasive tumor lines transplanted in mice with severe combined immunodeficiency (SCID). METHODS The UCT-1 tumor line, derived from bladder cancer, is a noninvasive transplantable tumor with no evidence of metastasis. The UCT-2 tumor line, derived from a renal pelvic tumor, extensively invades without metastasis. We examined gene expressions of MMPs-1, 2, 3, 7, 8, 9, 10, and 11, TIMPs-1, 2, and 3, and MT1-MMP in UCT-1 and 2 by semiquantitative polymerase chain reaction analysis. RESULTS Significantly higher gene expression of MMP-2 was detected in the invasive UCT-2 tumor line than in the noninvasive UCT-1 tumor line. Although both tumor lines expressed TIMP-1 and MT1-MMP, stronger gene expression of MT1-MMP was observed in the UCT-2 tumor line than in the UCT-1 tumor line. The other MMPs or TIMPs were not detected in either of the lines. CONCLUSIONS MMP-2 and MT1-MMP may have an important role in the invasion mechanism of urothelial cancers.

Indications for laparoscopic adrenalectomy for non-functional adrenal tumor with hypertension: usefulness of adrenocortical scintigraphy.

Aim:  Laparoscopic adrenalectomy is currently indicated for biochemically and clinically functional adrenal tumors and potentially malignant tumors of the adrenal glands. Non‐functional adenomas greater than 5 cm in diameter of the adrenal gland are generally considered to represent potentially malignant tumors. The present study shows indications of laparoscopic adrenalectomy for non‐functional adrenal tumors with hypertension in a retrospective fashion.

A convenient cancer vaccine therapy with in vivo transfer of interleukin 12 expression plasmid using gene gun technology after priming with irradiated carcinoma cells.

We studied interleukin (IL)-12 gene therapy using a gene gun as a new autologous vaccination strategy for cancer. In the first experiment, BALB/c mice were inoculated with syngeneic murine renal cancer cells (Renca) intradermally in the abdomen. This was followed by an injection of IL-12 expression plasmid using the gene gun. About 40% of the mice exhibited rejection of the tumor after the treatment and these mice also acquired immunological resistance against a secondary challenge with Renca cells. Based on these results, we examined whether antitumor activity can be potentiated when mice undergo combination treatment with intradermal inoculation of irradiated Renca cells and transfection with IL-12 gene. Inoculation of irradiated Renca cells alone was partially effective in inducing antitumor immunity, whereas the combined treatment remarkably intensified this effect. Moreover, this combined treatment inhibited tumor establishment and enhanced survival of the mice with tumor infiltration by CD4+ and CD8+ T cells, even when the treatment was started after tumor-implantation at a distant site. This antitumor effect was antigen specific and we confirmed the induction of antitumor cytotoxic T cells by this treatment. These results show that local cutaneous transfer of IL-12 expression plasmid using gene gun technology enhances systemic and specific antitumor immunity primed by irradiated tumor cells.