Tomoki Yamano

CCL21 Chemokine Regulates Chemokine Receptor CCR7 Bearing Malignant Melanoma Cells

Purpose: The chemokine CC-ligand 21/secondary lymphoid tissue chemokine (CCL21/SLC) regulates the homing of naïve T cells and dendritic cells that express CC-chemokine receptor 7 (CCR7) from distant sites to lymphoid tissue such as lymph nodes. We hypothesized that CCL21/SLC regulates the migration of CCR7-bearing melanoma cells from a primary lesion to regional tumor-draining lymph nodes. Experimental Design: Quantitative real-time reverse transcriptase-PCR (qRT) assay and immunohistochemistry (IHC) were used to assess the level of CCR7 expression in melanoma cell lines and in primary and metastatic melanoma tumors. Cell migration assay using melanoma cell lines was performed under the induction of CCL21/SLC. The CCL21/SLC expression level in tumor-draining sentinel lymph nodes (SLNs) was assessed by both qRT assay and IHC. Results: Melanoma cell lines and tumors demonstrated heterogeneous expression of CCR7 mRNA by qRT assay. There was strong functional correlation between CCR7 mRNA expression and cell migration induced by CCL21/SLC. IHC evidence of CCR7 expression in primary melanomas significantly (P = 0.02) correlated with Breslow thickness. Assessment of SLN from 55 melanoma patients by qRT assay demonstrated that CCL21/SLC mRNA expression level was significantly (P = 0.008) higher in pathologically melanoma-negative SLNs than in melanoma-positive SLNs. Conclusions: This report demonstrates a potential mechanism for recruitment and homing of CCR7(+) metastatic melanoma cells to tumor-draining lymph nodes, which express CCL21/SLC. The study also suggests that lymph nodes bearing metastasis may suppress CCL21/SLC production.

Epigenetic up-regulation of C-C chemokine receptor 7 and C-X-C chemokine receptor 4 expression in melanoma cells.

Histone deacetylation and DNA methylation establish epigenetic modifications, which through chromatin remodeling may result in gene silencing. We hypothesized that chemokine receptors C-C chemokine receptor 7 (CCR7) and C-X-C chemokine receptor 4 (CXCR4) on melanoma cells undergo epigenetic regulation. We investigated whether a histone deacetylase inhibitor and a demethylating agent influence CCR7 and CXCR4 expression on melanoma cells. Initially, microarray analysis was done to screen changes in chemokine receptor expression on melanoma cells after treatment with trichostatin A (TSA) and 5-Aza-2-deoxycytidine (5-Aza). CCR7 and CXCR4 mRNA expression were uniformly altered and selected for further investigation. Quantitative real-time reverse transcription-PCR assay, immunohistochemistry, and Western blot analysis were used to assess changes in mRNA and protein expression induced by TSA and 5-Aza in melanoma lines. Cell migration assays were conducted to assess the effects of altered CCR7 and CXCR4 expression on cell function. Treatment with TSA or 5-Aza increased gene expression of both CCR7 and CXCR4 in melanoma lines. TSA was the strongest enhancer. With combined treatment, CCR7 and CXCR4 mRNA expression was also up-regulated. Immunohistochemistry after combined treatment showed enhanced staining of both CCR7 and CXCR4 compared with control cells. Melanoma cell migration in TSA- and 5-Aza-treated cells was 7- and 2-fold higher than control cells for CCR7 and CXCR4, respectively. In summary, a histone deacetylase inhibitor and a demethylating agent up-regulated CCR7 and CXCR4 expression on melanoma cells. This increase in chemokine receptor expression correlated with functional activity. Most importantly, we have identified an epigenetic mechanism that may endogenously regulate chemokine receptor expression on melanoma cells.

A novel combination of suicide gene therapy and histone deacetylase inhibitor for treatment of malignant melanoma

One major problem associated with application of gene therapy to treatment of tumors is poor transgene expression. Although suicide gene therapy with the herpes simplex virus-thymidine kinase gene (HSV-tk) followed by administration of ganciclovir (GCV) was effective in the treatment of melanoma, it was still difficult to induce complete remission to cancer. A novel histone deacetylase inhibitor drug FR901229 was found to enhance transgene expression in tumor cells both in vitro and in vivo. Combination therapy with HSV-tklGCV and FR901228 by direct injection into tumor enhanced antimelanoma effects. The number of apoptotic cells in melanoma tumors was increased significantly (P<.05) after combined suicide gene therapy and FR901228. Six times injection of HSV-tk/GCV and FR901228 prolonged mice survival compared to that of HSV-tk/GCV injection alone (P=.021). In total, 56% (10 of 18) of the mice survived 120 days after combined suicide gene therapy and FR901228 treatment, and no new tumors appeared in the surviving mice. However, only 19% (3 of 16) of the mice survived when treated with suicide gene therapy alone. This novel strategy may be applicable as a therapeutic regimen for the treatment of aggressive types of cancers.

Enhanced antitumor efficacy of fiber-modified, midkine promoter-regulated oncolytic adenovirus in human malignant mesothelioma

Oncolytic virotherapy using adenoviruses has potential for therapeutic benefits in malignant mesothelioma. However, the downregulation of coxsackie virus/adenovirus receptor (CAR) expression is frequently a critical rate‐limiting factor that impedes the effectiveness of adenovirus serotype 5 (Ad5)‐based vectors in many cancer types. We evaluated CAR (Ad5 receptor) and CD46 (adenovirus serotype 35 [Ad35] receptor) expression in six human malignant mesothelioma cell lines. Very low CAR expression was observed in MSTO‐211H and NCI‐H2052 cells, whereas the other cell lines showed strong expression. In contrast, CD46 was highly expressed in all mesothelioma cell lines. On this basis, we replaced the CAR binding sequence of Ad5 with the CD46 binding sequence of Ad35 in the replication‐defective adenoviruses and the tumor‐specific midkine promoter‐regulated oncolytic adenoviruses. By this fiber modification, the infectivity, virus progeny production, and in vitro cytocidal effects of the adenoviruses were significantly enhanced in low CAR‐expressing MSTO‐211H and NCI‐H2052 cells, also resulting in similar or even higher levels in high CAR‐expressing mesothelioma cell lines. In MSTO‐211H xenograft models, the fiber‐modified oncolytic adenovirus significantly enhanced antitumor effect compared to its equivalent Ad5‐based vector. Our data demonstrate that Ad35 fiber modification of binding tropism in a midkine promoter‐regulated oncolytic Ad5 vector confers transductional targeting to oncolytic adenoviruses, thereby facilitating more effective treatment of malignant mesothelioma.

Immunity against breast cancer by TERT DNA vaccine primed with chemokine CCL21

Human telomerase reverse transcriptase (TERT) has been considered a potential tumor-associated antigen for active-specific immunotherapy. However, effective specific tumor antigen-specific immunity has been difficult to induce consistently by various TERT vaccine formulations. New adjuvant strategies have been employed, such as utilizing chemokines to attract T cells and antigen-presenting cells. Chemokine adjuvant strategies may enhance tumor antigen-specific immunity induced by vaccines. Therefore, we utilized chemokine ligand 21 (CCL21) as an adjuvant with a xenogeneic TERT DNA vaccine to induce tumor antigen-specific immunity against TERT-expressing breast cancer. The TERT DNA vaccine consisted of a plasmid containing the COOH terminal end of the TERT (cTERT) gene, encapsulated in multilayered liposomes with hemagglutinating virus of Japan coating. We demonstrated that CCL21 treatment before cTERT DNA vaccine, given intramuscularly, induced significantly higher anti-TERT specific cell-mediated immunity compared to cTERT DNA vaccine alone. Effective tumor antigen-specific immunity was shown both in prophylactic and therapeutic regimens against TS/A murine breast cancer. The study demonstrated that CCL21 administration before cTERT DNA vaccination significantly augmented tumor antigen-specific immunity against breast cancer.

Enhancement of the Anti‐tumor Effect of 5′‐Deoxy‐5‐fluorouridine by Transfection of Thymidine Phosphorylase Gene into Human Colon Cancer Cells

Thymidine phosphorylase (dThdPase) is an enzyme that converts 5′‐deoxy‐5‐fluorouridine (5′DFUR) to the toxic substance 5‐fluorouracil (5‐FU); it is also known to be a platelet‐derived endothelial cell growth factor. In order to investigate the feasibility of suicide gene therapy against colorectal cancer by means of the combination of 5′DFUR and the converting enzyme dThdPase, we transfected the dThdPase gene into the human colon cancer cell line SW480 and analyzed the growth pattern as well as the sensitivity to 5‐FU or 5′DFUR of the dThdPase‐transfected cells. The 50% inhibition (IC50) values of 5‐FU against the SW480 parental cells, control vector‐transfected cells SW480/V1, and dThdPase‐transfected cells SW480/dThdPase were approximately 4.9, 6.3, and 2.9 μM, respectively. The IC50 of SW480/dThdPase was lower than that of SW480 or SW480/V1, although the differences were not statistically significant. The IC50 values of 5′DFUR for SW480, SW480/V1, and SW480/dThdPase were approximately 300, 330, and 3.2 αM, respectively. The sensitivity to 5′DFUR of SW480/dThdPase was increased by about 100‐fold compared with that of SW480 or SW480/V1. With only 10% transfection efficacy, a high enough sensitivity to 5′DFUR was obtained to suppress the cell growth, indicating that a strong bystander effect was induced by this system. The in vivo growth of the s.c. transplanted SW480/dThdPase tumor in nude mice was significantly suppressed by i.p. injection of 5′DFUR compared with that in control mice that received phosphate‐buffered saline (PBS) treatment. These results suggest that gene therapy using the combination of 5′DFUR and the dThdPase gene may be a useful approach for treatment of colon cancer.

Metastatic lobular carcinoma of the breast masquerading as a primary rectal cancer

BackgroundColorectal metastasis of lobular carcinoma of the breast is a diagnostic challenge. It may macroscopically simulate primary colon cancer or inflammatory bowel disease. In some cases, the interval between the primary breast cancer and metastatic colorectal lesions is so long that the critical records for diagnosis including history might be lost or missed.Case presentationReported herein is a case of metastatic lobular carcinoma of the breast masquerading as a primary rectal cancer developed in a 62-year-old Japanese woman. The case initially presented as a circumferential rectal lesion, and information on the patient’s history of breast cancer was not noted. As the result of endoscopic biopsy, diagnosis of poorly differentiated rectal adenocarcinoma was made. The lesion was surgically resected after chemo-radiotherapy. Histopathological examination of the resected specimen with hematoxylin and eosin (HE) stain revealed a single-file arrangement of the tumor cells, reminiscent of lobular carcinoma of the breast. Immunohistochemical analysis revealed an immunophenotype consistent with lobular carcinoma of the breast. Because further review of the patient’s history revealed an occurrence of ‘poorly differentiated adenocarcinoma of the breast’, which she had experienced 24 years earlier, the final diagnosis of the lesion was made as rectal metastasis from lobular breast carcinoma.ConclusionsPoorly differentiated adenocarcinoma of the colorectum is rarer than that of the stomach. Linitis plastica-type cancer of the colorectum is also rarer than that of the stomach. A lesson from the present case is that before we conclude a linitis plastica-type cancer of poorly differentiated type as a primary colorectal cancer, it is critical to exclude a possibility of metastatic colorectal cancer.

Short-course radiotherapy with delayed surgery versus conventional chemoradiotherapy: A comparison of the short- and long-term outcomes in patients with T3 rectal cancer.

INTRODUCTION The aim of this study was to compare the short- and long-term outcomes between short-course radiotherapy with delayed surgery (SRT-delay) and a standard conventional chemoradiotherapy (CRT) regimen. METHODS Two collaborating institutions adopted different regimens; the SRT-delay regimen was selected by Meiwa Hospital and the CRT regimen was selected by Hyogo College of Medicine. The inclusion criteria were T3 middle and low rectal cancer patients treated with radical surgery after preoperative therapy. The median follow-up period was 44 months (range, 12-85). RESULTS From 2007 to 2013, 104 patients were treated using the SRT-delay regimen and 61 patients were treated using the CRT regimen. The pretreatment characteristics of the 2 groups were not significantly different. The sphincter-preserving rate (93.3%, 85.2%), T downstaging (37.5%, 37.7%), ypN(-) (74.0%, 67.2%), postoperative complications and the bowel, and urinary and sexual functioning of the SRT-delay regimen were noninferior to those of the CRT regimen. The 3-year local recurrence-free survival, recurrence-free survival, and overall survival in the SRT-delay and CRT groups were 90.6% and 90.6% (P = .764), 83.8% and 78.3% (P = .687) and 96.0% and 92.8% (P = .833), respectively. CONCLUSION The SRT-delay regimen was noninferior in terms of the downstaging effect, and oncologic and functional outcomes compared with the CRT regimen for T3 middle and low rectal cancer.

Pathologic evaluation of the response of mesorectal positive nodes to preoperative chemoradiotherapy in patients with rectal cancer

BACKGROUND The response of positive mesorectal lymph nodes to chemoradiotherapy remains largely unstudied in patients with rectal cancer. The aim of this study was to investigate the requirements of the total regression of positive nodes treated with chemoradiotherapy. METHODS The response of the primary tumor was evaluated according to the tumor regression grade (TRG 0-4) in resected specimens, and positive lymph nodes were assessed according to the lymph node regression grade (LRG 1-3), with TRG 4 and LRG 3 indicating total regression. We investigated the relationships among TRG, LRG, and the sizes of positive lymph nodes. RESULTS Among 178 patients, 68 (38.2%) had 200 positive lymph nodes. We first investigated the relationship of positive nodes to TRG and LRG and found that the response of the primary tumor to chemoradiotherapy correlated with the response of positive nodes. Next, we investigated the correlation between LRG and the size of positive nodes. At TRG 1 and 2, LRG score was not correlated with the positive node size. In contrast, at TRG 3, LRG score was correlated with the size of positive nodes. Next, our assessment of the relationship between the sizes of positive nodes and complete degeneration to LRG 3 showed that the most accurate cut-off score on receiver-operator-characteristics curve analysis was 6 mm in maximum diameter for TRG 3. CONCLUSION The requirements of the total regression of positive nodes are 1) degeneration of the primary tumor to TRG 3 and 2) a positive node diameter of <6 mm.

Oncolytic virotherapy for osteosarcoma using midkine promoter-regulated adenoviruses

Oncolytic virotherapy using adenoviruses has potential therapeutic benefits for a variety of cancers. We recently developed MOA5, a tumor-specific midkine promoter-regulated oncolytic vector based on human adenovirus serotype 5 (Ad5). We modified the binding tropism of MOA5 by replacing the cell-binding domain of the Ad5 fiber knob with that from another adenovirus serotype 35 (Ad35); the resulting vector was designated MOA35. Here we evaluated the therapeutic efficacies of MOA5 and MOA35 for human osteosarcoma. Midkine mRNA expression and its promoter activity was significantly high in five human osteosarcoma cell lines, but was restricted in normal cells. Very low levels of adenovirus cellular receptor coxsackievirus/adenovirus receptor (CAR) (Ad5 receptor) expression were observed in MNNG-HOS and MG-63 cells, whereas high levels of CAR expression were seen in the other osteosarcoma cell lines. By contrast, CD46 (Ad35 receptor) was highly expressed in all osteosarcoma cell lines. Infectivity and in vitro cytocidal effect of MOA35 was significantly enhanced in MNNG-HOS and MG-63 cells compared with MOA5, although the cytocidal effects of MOA5 were sometimes higher in high CAR-expressing cell lines. In MG-63 xenograft models, MOA35 significantly enhanced antitumor effects compared with MOA5. Our findings indicate that MOA5 and MOA35 allow tailored virotherapy and facilitate more effective treatments for osteosarcoma.