Chisako Yamauchi

Targeting of Bone-Derived Insulin-Like Growth Factor-II by a Human Neutralizing Antibody Suppresses the Growth of Prostate Cancer Cells in a Human Bone Environment

Purpose: Advanced prostate cancer frequently involves the bone, where the insulin-like growth factor (IGF)-II is abundant. However, the importance of IGF-II in bone metastasis from prostate cancer is uncertain. The present study was aimed at examining the therapeutic importance of targeting IGF-II in bone metastases from prostate cancer. Experimental Design: We investigated whether inhibiting IGF-II using a human neutralizing antibody (m610) suppresses the growth of prostate cancer cells in a human bone environment. Human MDA PCa 2b prostate cancer cells were inoculated into human adult bone implanted into mammary fat pad of nonobese diabetic/severe combined immunodeficient mice or inoculated into mammary fat pad of the mice without human bone implantation. The mice were treated with m610 or a control antibody (m102.4) once weekly for 4 weeks immediately after inoculation with MDA PCa 2b cells. Results: Histomorphologic examination indicated that m610 treatment significantly decreased the MDA PCa 2b tumor area in the human bone compared with the control. Ki-67 immunostaining revealed that the percentage of proliferating cancer cells in the m610-treated bone tumor sections was significantly lower than that in the control. m610 had no effect on MDA PCa 2b tumor growth in the absence of implanted human bone. m610 prevented the in vitro IGF-II–induced proliferation of MDA PCa 2b cells. Conclusions: Our results indicate that IGF-II plays an important role in the prostate cancer cell growth in human bone, suggesting that targeting it by neutralizing antibodies offers a new therapeutic strategy for bone metastasis from prostate cancer. Clin Cancer Res; 16(1); 121–29

Prognostic Impact of CD204-Positive Macrophages in Lung Squamous Cell Carcinoma: Possible Contribution of Cd204-Positive Macrophages to the Tumor-Promoting Microenvironment

Introduction: Tumor-associated macrophages (TAMs) are recruited into cancer-induced stroma and produce a specific microenvironment for cancer progression. CD204 (+) TAMs are reportedly related to tumor progression and clinical outcome in some tumors. The aim of this study was to clarify the correlation between CD204 (+) TAMs and the clinicopathological features of lung squamous cell carcinoma. Methods: We investigated the relationships between the numbers of CD204 (+) TAMs and clinicopathological factors, microvessel density, and the numbers of Foxp3 (+) lymphocytes in 208 consecutively resected cases. We also examined the relationships between the numbers of CD204 (+) TAMs and the expression levels of cytokines involved in the migration and differentiation of CD204 (+) TAMs. Results: A high number of CD204 (+) TAMs in the stroma was significantly correlated with an advanced p-stage, T factor, N factor, and the presence of vascular and pleural invasion. A high number of CD204 (+) TAMs in the stroma was also a significant prognostic factor for all p-stages and p-stage I. Moreover, the numbers of CD204 (+) TAMs were correlated with the microvessel density and the numbers of Foxp3 (+) lymphocytes. A high number of CD204 (+) TAMs was strongly correlated with the tissue expression level of monocyte chemoattractant protein-1. CD204 (+) TAMs were shown to be significant independent prognostic factors in a multivariate analysis. Conclusions: CD204 (+) TAMs were an independent prognostic factor in lung squamous cell carcinoma. CD204 (+) TAMs, along with other tumor-promoting stromal cells such as regulatory T cells and endothelial cells, may create tumor-promoting microenvironments.

Forkhead box P3 regulatory T cells coexisting with cancer associated fibroblasts are correlated with a poor outcome in lung adenocarcinoma

Recently, an association between tumor infiltrating Forkhead box P3 regulatory T cells (Treg) and an unfavorable prognosis has been clinically shown in some cancers, but the mechanism of Treg induction in the tumor microenvironment remains uncertain. The aims of the present study were to examine the relationship between Treg and patient outcome and to investigate whether Treg induction is influenced by the characteristics of cancer‐associated fibroblasts (CAF) in lung adenocarcinoma. The numbers of Treg in both the tumor stroma and the tumor nest were counted in 200 consecutive pathological stage I lung invasive adenocarcinoma specimens. To examine whether the characteristics of CAF influence Treg induction, we selected and cultured CAF from low Treg and high Treg adenocarcinoma. The number of Treg was much higher in the stroma than in the nest (P < 0.01). Patients with high Treg had a significantly poorer prognosis than those with low Treg (overall survival: P = 0.03; recurrence‐free survival: P = 0.02; 5‐year overall survival: 85.4% vs 93.0%). Compared with the CAF from low Treg adenocarcinoma, culture supernatant of the CAF from high Treg adenocarcinoma induced more Treg (P = 0.01). Also, CAF from high Treg adenocarcinoma expressed significantly higher mRNA levels of transforming growth factor‐β (P = 0.01) and vascular endothelial growth factor (P = 0.01), both of which are involved in Treg induction. Our studies suggest the possibility that CAF expressing immunoregulatory cytokines may induce Treg in the stroma, creating a tumor‐promoting microenvironment in lung adenocarcinoma that leads to a poor outcome.

High Mobility Group Box1 (HMGB1) released from cancer cells induces the expression of pro‐inflammatory cytokines in peritoneal fibroblasts

High Mobility Group Box1 protein (HMGB1), one of the mediators of inflammation, is associated with tumorigenesis. The HMGB1‐Receptor for advanced glycation end‐products (RAGE) in gastric adenocarcinoma tissues promoted gastric cancer growth, however, there are no reports concerning the relationship between the expression of HMGB1 in gastric cancer and cancer‐related inflammation. Fibroblasts exist most abundantly on cancer tissue where inflammation occurs. So, we studied the effects of HMGB1 released from cancer cells on the fibroblasts. The expression of HMGB1 in cancer cells and nuclear factor‐kappa B (NF‐kB) in fibroblasts were evaluated immunohistochemically in human gastric cancer specimens. Cytoplasmic HMGB1 expression in the cancer cells and nuclear translocation of NF‐kB in fibroblasts were detected at deeper invasion. To determine whether HMGB1 released from cancer cells induces the expression of pro‐inflammatory cytokines in fibroblasts, we analyzed the activation of Toll‐like receptor (TLR) signaling. Fibroblasts stimulated by recombinant HMGB1 and the HSC44PE‐conditioned medium showed the phosphorylation of Interleukin‐1 receptor associated‐kinase 4 (IRAK4), nuclear translocation of NF‐kB, and enhanced pro‐inflammatory cytokine expression. Treatment with HSC44PE‐conditioned‐medium transfected with siRNA‐HMGB1 reduced the expressions of pro‐inflammatory cytokines in the fibroblasts. We propose that HMGB1 released from cancer cells induces the expression of pro‐inflammatory cytokines in peritoneal fibroblasts through the HMGB1‐TLR2/4 pathway.

Tumor cells of non-hematopoietic and hematopoietic origins express activation-induced C-type lectin, the ligand for killer cell lectin-like receptor F1

Killer cell lectin-like receptor F1 (KLRF1) is an activating C-type lectin-like receptor expressed on human NK cells and subsets of T cells. In this study, we show that activation-induced C-type lectin (AICL) is a unique KLRF1 ligand expressed on tumor cell lines of hematopoietic and non-hematopoietic origins. We screened a panel of human tumor cell lines using the KLRF1 reporter cells and found that several tumor lines expressed KLRF1 ligands. We characterized a putative KLRF1 ligand expressed on the U937 cell line. The molecular mass for the deglycosylated ligand was 28 kDa under non-reducing condition and 17 kDa under reducing condition, suggesting that the KLRF1 ligand is a homodimer. By expression cloning from a U937 cDNA library, we identified AICL as a KLRF1 ligand. We generated mAbs against AICL to identify the KLRF1 ligands on non-hematopoietic tumor lines. The anti-AICL mAbs stained the tumor lines that express the KLRF1 ligands and importantly the interaction of KLRF1 with the KLRF1 ligand on non-hematopoietic tumors was completely blocked by the two anti-AICL mAbs. Moreover, NK cell degranulation triggered by AICL-expressing targets was partially inhibited by the anti-AICL mAb. Finally, we demonstrate that AICL is expressed in human primary liver cancers. These results suggest that AICL is expressed on tumor cells of non-hematopoietic origins and raise the possibility that AICL may contribute to NK cell surveillance of tumor cells.

Grading system for lymph vessel tumor emboli for prediction of the outcome of invasive ductal carcinoma of the breast

There are no suitable histologic diagnostic clues for determining the true biological malignancy of invasive ductal carcinomas associated with lymph vessel tumor emboli. The purpose of this study was to devise a grading system for lymph vessel tumor emboli in invasive ductal carcinomas that would allow accurate prediction of the outcome of invasive ductal carcinoma patients with lymph vessel invasion. We classified 393 invasive ductal carcinomas into the following 4 grades according to the number of mitotic and apoptotic figures in tumor cells in lymph vessels at 1 high-power field: grade 0, no lymph vessel invasion; grade 1, absence of mitotic and apoptotic figures, presence of any number of mitotic figures and absence of apoptotic figures, or absence of mitotic figures and presence of any number of apoptotic figures; grade 2, 1 to 4 mitotic figures and 1 or more of apoptotic figures, or 1 or more of mitotic figures and 1 to 6 apoptotic figures; and grade 3, more than 4 mitotic figures and more than 6 apoptotic figures. The mortality rate increased with the grade, and the mortality rate of patients with grade 3 lymph vessel tumor emboli was more than 70%. Multivariate analyses with well-known prognostic factors demonstrated that grade 3 lymph vessel tumor emboli significantly increased the hazard rates for tumor recurrence, and tumor death independent of adjuvant therapy status, nodal status, or invasive tumor size. The grading system for lymph vessel tumor emboli is the best histologic grading system for accurately predicting the outcome of patients with invasive ductal carcinoma of the breast.

E‐cadherin expression on human carcinoma cell affects trastuzumab‐mediated antibody‐dependent cellular cytotoxicity through killer cell lectin‐like receptor G1 on natural killer cells

Trastuzumab is a recombinant antibody drug that is widely used for the treatment of HER2‐overexpressing breast carcinoma. Despite encouraging clinical results, many HER2‐overexpressing carcinomas are primarily resistant to trastuzumab. We attempted to explain trastuzumab resistance and search for solutions. Since the killer cell lectin‐like receptor G1 (KLRG1), an inhibitory receptor expressed on subsets of natural killer (NK) cells recognizes E‐cadherin as ligands and may inhibit immune responses by regulating the effector function of NK cells, we used HER2‐overexpressing carcinoma cells which were expressing E‐cadherin to investigate the role of antibody‐dependent cellular cytotoxicity (ADCC) through KLRG1 on NK cells in vitro and vivo. The results indicated that HER2‐overexpressing carcinoma cells were killed by trastuzumab‐mediated ADCC and the ADCC activity was reflected the degree of E‐cadherin expression on carcinoma cells. We found that expression of E‐cadherin was shown to be a predictor of response to trastuzumab‐based treatment for HER2‐overexpressing carcinomas, furthermore, trastuzumab‐mediated ADCC was markedly enhanced by KLRG1‐negative peripheral blood mononuclear cells (PBMCsKLRG1(−)).

Correlation between concordance of tracers, order of harvest, and presence of metastases in sentinel lymph nodes with breast cancer.

BackgroundThere are various methods for the detection of sentinel lymph nodes (SLNs) in breast cancer by using a combined method with blue dye and radioisotope (RI) tracers. The purpose of the study was to reveal any correlation between concordance of the tracers and the order of harvest with the presence of metastases in SLNs.MethodsThe outcomes were reviewed in 408 cases with stage 0 to II breast cancer; the combined method was used in which blue dye and RI were injected subcutaneously around the tumor. The radioactivity and blue staining in each harvested SLN were checked.ResultsIn 330 cases (81%), SLNs contained both blue dye and RI tracers (blue-hot cases), and in 42 (10%) and 31 (8%) cases, the SLNs contained only the blue stain (blue-only cases) and only RI (hot-only cases), respectively. The overall metastatic rate was 25% on a patient basis. Blue-only cases had a higher rate (42%) of metastasis than hot-only cases (14%). The rate of nodes containing both blue dye and RI gradually decreased from the first SLNs harvested to the third SLNs harvested. The rate of nodes containing RI only increased with the number harvested, and there was not so much change in the rate of nodes containing blue only.ConclusionsThese data suggest that RI tracer could detect a wide range of SLNs and that the blue dye tracer could efficiently detect SLNs with metastasis. The combined methods compensates for the deficiencies of each method and thus will probably help to prevent missing SLNs.