Kouichiro Kawano

Expression of activated signal transducer and activator of transcription-3 predicts poor prognosis in cervical squamous-cell carcinoma

Background:Stat3 is a member of the Janus-activated kinase/STAT signalling pathway. It normally resides in the cytoplasm and can be activated through phosphorylation. Activated Stat3 (p-Stat3) translocates to the nucleus to activate the transcription of several molecules involved in cell survival and proliferation. The constitutive activation of Stat3 has been shown in various types of malignancies, and its expression has been reported to indicate a poor prognosis. However, the correlation between the constitutive activation of Stat3 and the prognosis of cervical cancer patients has not been reported.Methods:The immunohistochemical analysis of p-Stat3 expression was performed on tissues from 125 cervical squamous-cell carcinoma patients who underwent extended hysterectomy and pelvic lymphadenectomy, and the association of p-Stat3 expression with several clinicopathological factors and survival was investigated.Results:Positive p-Stat3 expression was observed in 71 of 125 (56.8%) cases and was significantly correlated with lymph node metastasis, lymph vascular space invasion, and large tumour diameter (>4 cm) by Fishers exact test. Kaplan–Meier survival analysis showed that p-Stat3 expression was statistically indicative of a poor prognosis for overall survival (P=0.006) and disease-free survival (P=0.010) by log-rank test.Conclusion:These data showed that p-Stat3 expression in cervical cancer acts as a predictor of poor prognosis.

Cap43/NDRG1/Drg-1 is a molecular target for angiogenesis and a prognostic indicator in cervical adenocarcinoma.

Cap43 is a nickel- and calcium-inducible gene that plays important roles in the primary growth of malignant tumors, as well as in invasion and metastasis, most likely through its ability to induce cellular differentiation. This study investigated associations of Cap43 expression with angiogenesis and other clinicopathological factors in cervical adenocarcinoma. The clinical records of 100 women who underwent surgery for cervical adenocarcinoma were reviewed retrospectively. Microvessel density and the expression of Cap43 and VEGF in the surgical specimens were evaluated immunohistochemically. The Cap43 expression level was significantly associated with angiogenesis, tumor diameter, stromal invasion, lymphovascular space invasion, lymph node metastasis, and histopathological differentiation. Kaplan-Meier analysis showed a significant association between the Cap43 expression level and survival: high Cap43 expression was related to poor survival. Our results suggest that increased expression of Cap43 is associated with angiogenesis and may be a poor prognostic indicator in women with cervical adenocarcinoma.

Assessment of immunological biomarkers in patients with advanced cancer treated by personalized peptide vaccination

To investigate immunological biomarkers to predict overall survival of advanced cancer patients under treatment with personalized peptide vaccination, correlations between overall survival and biomarkers, including cytotoxic T lymphocyte (CTL) and immunoglobulin G (IgG) responses to the vaccinated peptides, were investigated in 500 advanced cancer patients who received personalized peptide vaccination from October 2000 to October 2008. The best clinical response was assessed for in 436 patients, 43 patients (10%) had partial response, 144 patients (33%) had stable disease and 249 patients (57%) had progressive, with a median overall survival of 9.9 months. Both lymphocyte counts prior to the vaccination (P = 0.0095) and increased IgG response (P = 0.0116) to the vaccinated peptides, along with performance status (P < 0.0001), well correlated with overall survival. To confirm the superiority of IgG response to CTL response, the samples from advanced castration-resistant prostate cancer patients who survived more than 900 days (n=20) and those who died within 300 days (n=23) were analyzed further. As a result, both the numbers of peptides, to which increased IgG responses were observed, and the fold increases in IgG levels were significantly higher in long-term survivors (P = 0.000282 and P = 0.00045). In contrast, CTL responses were not statistically different between the two groups. Both lymphocyte numbers and IgG response were thus suggested to be biomarkers of cancer vaccine for advanced cancer patients.

Melanoma differentiation-associated gene-7 (mda-7 )/interleukin (IL)-24 induces anticancer immunity in a syngeneic murine model

Previous studies have shown that the human melanoma differentiation-associated gene-7 (mda-7)/interleukin-24 (IL-24) has tumor-suppressor activity in vitro and in vivo. Additionally, in vitro studies using human peripheral blood mononuclear cells indicate that mda-7/IL-24 has TH1 cytokine-like activity. However, the individual properties of mda-7/IL-24 have been previously examined separately. Thus, there is not a single study that has examined both, antitumor and proimmune properties of mda-7/IL-24. Furthermore, the tumor suppressive activity and the cytokine activity of mda-7/IL-24 have not been previously tested in an immunocompetent setting. We therefore in the present study evaluated the antitumor and immune properties of mda-7/IL-24 in a murine syngeneic tumor model. In vitro, adenovirus-mediated mda-7 gene (Ad-mda7) transfer to murine fibrosarcoma (UV2237m; MCA16) and normal (10T1/2) cells significantly inhibited growth (P=0.001) and induced apoptosis in tumor cells but not in normal cells. In vivo, intratumoral administration of Ad-mda7 resulted in significant inhibition of tumor growth (P<0.05), with a subset of mice showing complete tumor regression. We next evaluated the immune potentiation activity of Ad-mda7 in a cancer vaccine model. UV2237m cells transfected with Ad-mda7 and injected into syngeneic immunocompetent C3H mice were unable to grow; however, they did grow in immunocompromised nude mice. These tumor-free C3H mice, when challenged with parental tumor cells experienced no tumor growth, suggesting induction of systemic immunity. Moreover, splenocytes prepared from vaccinated C3H mice demonstrated higher proliferative activity and produced elevated levels of TH1 cytokines compared with those from control mice. An in vitro subset analysis of splenocytes from vaccinated mice demonstrated a significant increase in the CD3+CD8+ but not the CD3+CD4+ cell population (P=0.019). Thus Ad-mda7 treatment of syngeneic tumors induces tumor cell death and promotes immune activation, leading to anticancer immunity.

Fine Specificity of High Molecular Weight-Melanoma-Associated Antigen-Specific Cytotoxic T Lymphocytes Elicited by Anti-Idiotypic Monoclonal Antibodies in Patients with Melanoma

HLA-A2-restricted CTLs, which lysed high molecular weight (HMW)-melanoma-associated antigen (MAA)+ melanoma cells, were induced in patients with melanoma immunized with MELIMMUNE, a combination of the murine anti-idiotypic (anti-id) monoclonal antibodies (mAb) MEL-2 and MF11–30 (MW Pride et al., Clin Cancer Res 1998;4:2363.). In the present study we investigated whether CTL epitopes are present in anti-id mAb MF-11–30 and activate T cells to recognize HMW-MAA on melanoma cells. One candidate epitope in the mAb MF11–30 VH chain, VH (3–11), was selected based on the presence of HLA-A2 anchor residues and partial homology with the HMW-MAA epitope, HMW-MAA (76–84). Lymphocytes from HLA-A2+-immunized patients proliferated to VH (3–11) peptide and to a variant HMW-MAA peptide to a significantly greater extent than autologous lymphocytes stimulated with an irrelevant peptide and lymphocytes from nonimmunized patients. No proliferative response was detected to the wild-type HMW-MAA peptide (76–84). Significant increase in IFN-γ production but not in interleukin 10 production in response to VH (3–11) and to variant HMW-MAA peptide (76–84) was observed in lymphocytes from the immunized patients. Stimulation of lymphocytes from HLA-A2+ patients with the two peptides induced CTL, which lysed HMW-MAA+/HLA-A2+ A375SM melanoma cells. This is the first report documenting the presence of immunogenic peptides in a murine anti-id mAb for a defined epitope expressed by a human melanoma-associated antigen. These results may be relevant for development of novel vaccines based on homology between anti-id mAb and tumor-associated antigen amino acid sequences.

Induction of Tumor-Reactive CTL by C-Side Chain Variants of the CTL Epitope HER-2/neu Protooncogene (369-377) Selected by Molecular Modeling of the Peptide: HLA-A2 Complex

To design side chain variants for modulation of immunogenicity, we modeled the complex of the HLA-A2 molecule with an immunodominant peptide, E75, from the HER-2/neu protooncogene protein recognized by CTL. We identified the side chain orientation of E75. We modified E75 at the central Ser5 (E75 wild-type), which points upward, by removing successively the HO (variant S5A) and the CH2-OH (variant S5G). Replacement of the OH with an aminopropyl (CH2)3-NH3 (variant S5K) maintained a similar upward orientation of the side chain. S5A and S5G were stronger stimulators while S5K was a weaker stimulator than E75 for induction of lytic function, indicating that the OH group and its extension hindered TCR activation. S5K-CTL survived longer than did CTL induced by E75 and the variants S5A and S5G, which became apoptotic after restimulation with the inducer. S5K-CTL also recognized E75 endogenously presented by the tumor by IFN-γ production and specific cytolysis. S5K-CTL expanded at stimulation with E75 or with E75 plus agonistic anti-Fas mAb. Compared with S5K-CTL that had been restimulated with the inducer S5K, S5K-CTL stimulated with wild-type E75 expressed higher levels of E75+ TCR and BCL-2. Activation of human tumor-reactive CTL by weaker agonists than the nominal Ag, followed by expansion with the nominal Ag, is a novel approach to antitumor CTL development. Fine tuning of activation of tumor-reactive CTL by weak agonists, designed by molecular modeling, may circumvent cell death or tolerization induced by tumor Ag, and thus, may provide a novel approach to the rational design of human cancer vaccines.

Activation of Tumor Antigen-Specific Cytotoxic T Lymphocytes (CTLs) by Human Dendritic Cells Infected with an Attenuated Influenza A Virus Expressing a CTL Epitope Derived from the HER-2/neu Proto-Oncogene

ABSTRACT The development of cancer vaccines requires approaches to induce expansion and functional differentiation of tumor antigen-specific cytotoxic T lymphocyte (CTL) effectors which posses cytolytic capability and produce cytokines. Efficient induction of such cells is hindered by the poor immunogenicity of tumor antigens and by the poor transduction efficiency of dendritic cells (DCs) with current nonreplicating vectors. We have investigated the use of influenza A virus, a potent viral inducer of CTLs, as a vector expressing the immunodominant HER-2 CTL epitope KIF (E75). For this purpose, an attenuated influenza A/PR8/34 virus with a truncated nonstructural (NS1) gene was generated containing the E75 epitope in its neuraminidase protein (KIF-NS virus). Stimulation of peripheral blood mononuclear cells from healthy donors and of tumor-associated lymphocytes from ovarian and breast cancer patients with DCs infected with KIF-NS virus (KIF-NS DC) induced CTLs that specifically recognized the peptide KIF and HER-2-expressing tumors in cytotoxicity assays and secreted gamma interferon (IFN-γ) and interleukin-2 at recall with peptide. Priming with KIF-NS DCs increased the number of E75+ CD45RO+ cells by more than 10-fold compared to nonstimulated cells. In addition, KIF-NS virus induced high levels of IFN-α in DCs. This is the first report demonstrating induction of human epitope-specific CTLs against a tumor-associated antigen with a live attenuated recombinant influenza virus vector. Such vectors may provide a novel approach for tumor antigen delivery, lymphocyte activation, and differentiation in human cancer vaccine development.

Prostate Tumor Cells Infected with a Recombinant Influenza Virus Expressing a Truncated NS1 Protein Activate Cytolytic CD8+ Cells To Recognize Noninfected Tumor Cells

ABSTRACT Many viral oncolytic approaches against cancer are based on the ability of specific viruses to replicate in tumors expressing components of the constitutively activated Ras/mitogen-activated protein kinase (MAPK) pathways and/or inhibited or dysregulated alpha/beta interferon (IFN-α/β) response pathways. A major issue when considering these approaches is their applicability to tumors that lack activated Ras. To identify the effector mechanisms activated by oncolytic viruses, we investigated inhibition of proliferation of the prostate cancer line LNCap by the recombinant TR-NS1 influenza A virus, a genetically attenuated influenza A/PR8/34 virus expressing a truncated nonstructural protein (NS1) of 126 amino acids. LNCap cells lack constitutively activated MAPK, extracellular signal-regulated kinase (ERK), and p38 and are resistant to death by IFN-α. Truncation of the NS1 protein of influenza viruses is known to result in viral attenuation due to a reduced ability of the NS1 to inhibit the IFN-α/β response. Infection with TR-NS1 virus rapidly activated ERK-1 more than ERK-2 in LNCap cells. Importantly, TR-NS1 virus infection transiently inhibited cell proliferation and induced apoptosis in LNCap cells. Addition of peripheral blood mononuclear cells (PBMC) and interleukin 12 (IL-12) to TR-NS1 virus-infected LNCap cells (TR-NS1-LNCap) resulted in faster elimination of TR-NS1-LNCap cells compared with LNCap cells. Moreover, TR-NS1-LNCap cells induced IFN-γ in PBMC. The levels of IFN-γ were amplified by IL-12. TR-NS1-LNCap cells also induced tumor-lytic cytotoxic T lymphocytes (CTL). These CTL lysed noninfected LNCap cells in a CD8-dependent manner. Activation of cellular immunity to tumor cells by viruses is an intriguing effector pathway, which should be especially significant for elimination of human tumors that lack activated Ras.

Fertility-preserving treatment for patients with malignant germ cell tumors of the ovary

Aim:  The aim of this study was to investigate whether fertility preservation influences the clinical outcome in patients with malignant germ cell tumors of the ovary (MGCTO).

Peptide YY producing strumal carcinoid of the ovary as the cause of severe constipation with contralateral epithelial ovarian cancer

Primary ovarian carcinoid tumors are rare. It has been reported that constipation was a presenting symptom in some patients with ovarian carcinoid. A case of strumal carcinoid of the ovary with contralateral clear cell adenocarcinoma of the ovary discovered with a complaint of constipation is described. Constipation was dramatically improved by resectioning the tumor. The tumor cells were positive for peptide YY (PYY) in the carcinoid component, but not in any other components. The present case could provide evidence of the correlation between constipation and PYY that has been reported elsewhere. Interestingly, the constipation caused by PYY also helped in discovering epithelial ovarian cancer.