Eiji Mekata

OX40 costimulation can abrogate Foxp3+ regulatory T cell-mediated suppression of antitumor immunity

Regulatory T cells (Tregs) play an important role in maintaining immunological tolerance that is one of the main obstacles to overcome for improving antitumor immunity. Recently, the Treg has been shown to constitutively express OX40 (CD134), which is a member of the TNF‐receptor family that is transiently expressed on effector T cells after TCR triggering, and through which the signal enhances effector T‐cell proliferation and memory T‐cell development. However, little is known about the role of OX40 costimulation to Tregs in tumor immunology. Here we show that OX40 signaling modulates the function of naturally occurring Tregs in vitro and in vivo. Foxp3 expression on Tregs was reduced by OX40 costimulation, but not by IL‐2 stimulation. Tregs suppressed the proliferation of naïve CD4+ CD25− T cells after TCR triggering, in contrast, OX40 costimulated Tregs that reduced Foxp3 expression reversed the suppressive function. In addition, Tregs inhibited the proliferation of TCR‐stimulated (primed) CD4+ T cells and naïve CD8+ T cells after TCR‐mediated activation, however, Tregs with OX40 costimulation lost their suppressive function. Interestingly, Tregs minimally suppressed the proliferation or the cytokine secretion of Ag‐specific CD8+ T cells after Ag‐restimulation. Furthermore, Tregs suppressive function to the antitumor effect was reversed by OX40 costimulation in vivo. Our data indicate that, in addition to controlling effector T‐cell function, OX40 costimulation directly controls Treg‐mediated suppression in tumor immunity.

Clinical potential of an antitumor drug sensitivity test and diffusion-weighted MRI in a patient with a recurrent solid pseudopapillary tumor of the pancreas

A solid pseudopapillary tumor (SPT) of the pancreas is a rare type of pancreatic neoplasm found predominantly in young women. SPTs typically behave as though benign; however, in some cases they also have malignant potential. We encountered a rare case of a recurrent SPT that developed 4 years after the initial surgery in an elderly male patient. Abdominal computed tomography (CT) revealed that the 61-year-old patient had four intra-abdominal masses, suggesting a recurrence of SPT. The patient had a history of distal pancreatectomy due to SPT in the pancreatic tail 4 years previously. These tumors showed positive signals on diffusion-weighted magnetic resonance imaging (MRI), and were treated successfully by aggressive surgical resection. Microscopic diagnosis was compatible with recurrent tumors of SPT. A chemosensitivity test, the collagen gel droplet-embedded culture drug sensitivity test (CD-DST), showed that the resected tumors were sensitive to several antitumor drugs. We suggest that the CD-DST may be used to indicate promising antitumor agents for treating SPTs with malignant tendencies. In addition, a diffusion-weighted MRI can be useful for accurately visualizing SPTs of the pancreas.

Prognostic role of CD10⁺ myeloid cells in association with tumor budding at the invasion front of colorectal cancer.

The expression of CD10 in tumor cells has been reported to correlate with liver metastasis in colorectal cancer (CRC). However, fibroblasts and immune cells positive for CD10 at the tumor invasion front have not been comprehensively studied. We classified CD10 expression patterns into three types of cells, tumor cells (tCD10), stromal myofibroblasts (sCD10), and immune cells (iCD10), and investigated their correlation with the expression of transforming growth factor‐β (TGF‐β1) protein and tumor budding grade. Several cell surface markers were stained to detect the phenotype of iCD10+ cells, including CD3, CD20, CD11b, CD14, CD15, and CD163. Specimens and follow‐up data of 206 CRC patients were examined. In multivariate analysis, iCD10 could be an independent prognostic factor for both recurrence‐free survival and overall survival in stage I–III CRC (hazard ratio, 2.522 [1.299–4.896], P = 0.006; 2.890 [1.357–6.157], P = 0.006, respectively). The expression of sCD10 and iCD10 was strongly correlated with TGF‐β1 expression in tumor cells and tumor budding grade. The phenotype of iCD10+ cells was CD11b+ and CD15+ granulocytes. The infiltration of sCD10+ fibroblasts and iCD10+ granulocytes at the tumor invasion front might interact with TGF‐β1 protein expression and enhance tumor budding grade. The expression level of iCD10 at the tumor invasion front represented an independent prognostic biomarker in stage I–III CRC and could be integrated into a new staging system. (Cancer Sci 2011; 102: 1724–1733)

Mannan-Binding Protein, a C-Type Serum Lectin, Recognizes Primary Colorectal Carcinomas through Tumor-Associated Lewis Glycans

Mannan (mannose)-binding protein (MBP) is a C-type serum lectin that plays a key role in innate immunity. MBP forms large multimers (200–600 kDa) and exhibits broad specificity for mannose, N-acetylglucosamine, and fucose. MBP exhibits high affinity for unique oligosaccharides that have been isolated from human colorectal carcinoma (SW1116) cells and characterized as highly fucosylated high m.w. type 1 Lewis glycans. In this study, we first demonstrated that MBP recognizes human primary colorectal carcinoma tissues through tumor-associated MBP ligands. We performed fluorescence-based histochemistry of MBP in human colorectal carcinoma tissues and showed that MBP clearly stained cancer mucosae in a Ca2+-dependent manner. Coincubation with plant (Aleuria aurantia) lectin, but not Con A, blocked MBP staining, indicating that fucose, rather than mannose, is involved in this interaction. The expression of MBP ligands was detected in 127 of 330 patients (38.5%), whereas, most significantly, there was no expression in 69 nonmalignant tissues. The MBP-staining pattern in cancer mucosae significantly overlapped with that of Lewis b [Fucα1-2Galβ1-3(Fucα1-4)GlcNAc] staining, but the Lewis b staining in normal tissues was not associated with MBP staining. In addition, the MBP staining correlated inversely with the expression of CA19-9 Ag, and MBP stained 11 of 25 (44%) CA19-9 (sialyl Lewis a [NeuAc(α2-3)Galβ1-3(Fucα1-4)GlcNAc])− colorectal carcinoma tissues. We found a favorable prognosis in patients with MBP ligand+ tumors. These results suggest that selective recognition of cancer cells by endogenous MBP seems to be associated with an antitumor effect and that tissue staining with MBP in combination with CA19-9 may serve as a novel indicator of colorectal carcinoma tissues.

Transmembrane mucin MUC1 overexpression and its association with CD10⁺ myeloid cells, transforming growth factor-β1 expression, and tumor budding grade in colorectal cancer.

The prognostic value of mucin expression has been reported in several studies. We examined the association between mucin expression and other previously reported prognostic factors, including infiltration of CD10+ myeloid cells, transforming growth factor‐β1 (TGF‐β1) expression, and tumor budding at invasion fronts. Immunohistochemical analysis of 206 colorectal samples was carried out to determine whether MUC1, MUC2, MUC4, and MUC5AC expression could predict the survival of colorectal cancer patients. Serial sections were stained for CD10, TGF‐β1, and pan‐cytokeratin in order to detect tumor budding. As per multivariate analyses, MUC1 expression appeared to be the most significant predictor of both recurrence‐free survival and overall survival. MUC4 was only significant to predict recurrence‐free survival, and MUC5AC could be a good marker in stage IV colorectal cancers that require additional chemotherapy. MUC1 (CD227) expression was associated with infiltration of CD10+ myeloid cells, TGF‐β1 expression, and tumor budding grade. These findings suggest that MUC1 is indicative of poor prognoses that may be associated with immunosuppression and epithelial–mesenchymal transition. Furthermore, MUC1 expression appears to be a chemoattractant for CD10+ stromal cells.

A case of catheter fracture of a totally implantable access port introduced through the right internal jugular vein

Totally implantable access ports (TIAPs) have been widely used for the safe delivery of chemotherapy or parenteral nutrition in patients with malignant disease and other debilitating diseases [1,2]. The pinchoff syndrome has been used to explain the fracture of catheters inserted through the subclavicular vein. The incidence of catheter fracture by the pinch-off syndrome is reported to be 1.1–5.0% [3,4]. To prevent the occurrence of catheter fracture in this manner, some researchers recommended that the catheter of TIAP was inserted through the right internal jugular vein [5,6]. We encountered an extremely rare case of catheter fracture of TIAP introduced through the right internal jugular vein. To the best of our knowledge, only one similar report has been published to date. The patient was a 35-year-old man with a history of left lower lobe resection for lung cancer (mucinous-alveolar carcinoma, mucious cell type, T2N0M0, stage Ib) and low anterior resection for rectal cancer (moderately differentiated adenocarcinoma, T3N1M1, stage IV). The patient underwent placement of TIAP (BARD MRI port, Medicon, Inc., Osaka, Japan), which was introduced through the right internal jugular vein under ultrasonographic guidance 25 days after low anterior resection for chemotherapy. There was no complication during the surgery for TIAP placement. Thereafter, the patient underwent chemotherapy consisting of 12 cycles of the mFOLFOX6 regimen. Six months after the first surgery, partial hepatic resection and microwave ablation therapy was performed for treatment of hepatic metastasis. Thereafter, chemotherapy was continued with 9 cycles of the FOLFIRI regimenþ bevacizumab, 6 cycles of TEGAFIRI (UFT/ LVþ irinotecan) regimen, and 5 months of cetuximab; with these treatment, the patient was maintained in stable disease. When premedication was administered 785 days after TIAP implantation, the patient complained of right cervical pain. Chest radiography revealed that the catheter had fractured at the level of the clavicle and a separated catheter tip had migrated into the heart (Fig. 1A). The separated catheter tip was removed through the right internal jugular vein by catheter intervention. The catheter had ruptured at a point 3 cm from its connection to the TIAP. On enquiry, it was ascertained that the patient routinely carried a backpack on his right shoulder. We confirmed that the strap of backpack passed over the catheter and compressed it against the clavicle, resulting in its fracture (Fig. 1B). Fig. 1. A: Chest X-ray images showed that the central venous catheter of the totally implantable access port (TIAP) had fractured on the right collarbone (single arrow). A fragment of the catheter was observed in the heart (double arrow). B: The strap of backpack came in contact and compressed the catheter, resulting in its fracture.

Pre-treatment with cyclophosphamide or OX40 (CD134) costimulation targeting regulatory T cell function enhances the anti-tumor immune effect of adoptively transferred CD8+ T cells from wild-type mice

Regulatory T cells (Tregs) are a major obstacle to the establishment of effective cancer immunotherapy. As mediators of immune tolerance, they are a critical target for pre-conditioning for adoptive immunotherapy. Here, we show that pre-treatment with cyclophosphamide or agonistic anti-OX40 mAb augments the anti-tumor immune effect of adoptive CD8+ T cell therapy in a clinically relevant wild-type model, as opposed to a TCR-transgenic mouse model. Tumor antigen-stimulated CD8+ T cells (7x106), including a small number (2.17x105) of tumor antigen-specific effector CD8+ T cells, were transferred into tumor-bearing mice. A response was detected in the adoptively transferred antigen-specific CD8+ T cells, but was insufficient for the eradication of the established tumor. However, pre-treatment with cyclophosphamide to reduce Tregs was shown to enhance the anti-tumor immune effect of the adoptively transferred CD8+ T cells. Moreover, we demonstrated for the first time that pre-treatment with OX40 costimulation, with the aim of nullifying Treg-mediated suppression, maintained the tumor-specific immune response of adoptively transferred CD8+ T cells, resulting in the eradication of the established tumor. These findings suggest that pre-conditioning with the aim of depleting Tregs is a useful strategy for adoptive cancer immunotherapy.

A Comparison of Outcomes and Complications of Totally Implantable Access Port Through the Internal Jugular Vein Versus the Subclavian Vein

Totally implantable access ports (TIAPs) are generally used in oncology. Few studies have addressed complications associated with the insertion site. A total of 233 consecutive oncology patients were enrolled to receive TIAP inserts via internal jugular vein (IJV) or subclavian vein (SV). Data on clinicopathologic parameters and early/late complications were retrospectively collected. No differences were found early and late complication rates. Catheter injury was observed more frequently in the IJV group (2.9%) than in the SV group (1.0%) without statistical significance. Multivariate logistic regression analysis showed that age, switch to palliative use of TIAP, and the distribution of diseases (low risk in patients with colorectal cancer) were independent risk factors for determining complications. In conclusion, TIAP insertion site showed no impact on the early and late complication rates. Catheter injury appears to occur at the same frequency with both approaches. Therefore, medical doctors may choose their preferred puncture site when performing TIAP insertion.

Hyperthermic intraperitoneal chemotherapy using a combination of mitomycin C,5-fluorouracil, and oxaliplatin in patients at high risk of colorectal peritoneal metastasis: A Phase I clinical study

INTRODUCTION The drugs and protocols used for hyperthermic intraperitoneal chemotherapy (HIPEC) vary among institutions. Here we show the efficacy of the 3-drug combination of mitomycin C (MMC), 5-fluorouracil (5FU), and oxaliplatin (OHP) in an in vitro simulation of HIPEC and the safety of HIPEC with these drugs during a Phase I study of patients at high risk of developing colorectal peritoneal metastasis. METHODS To simulate HIPEC, we used HCT116 and WiDr cells to assess the growth inhibitory efficacy of MMC 2 μg/mL, 5FU 200 μg/mL, and OHP 40 μg/mL as single drugs or their combination after an exposure time of 30 min at 37 or 42 °C. In addition, nine patients underwent surgical resection of tumors and HIPEC with MMC, 5FU, and an escalating dose of OHP (90/110/130 mg/m²). Dose-limiting toxicity was monitored. RESULTS In the simulation, the 3-drug combination showed marked tumor-suppressive effects compared with those from ten times higher dose of OHP 400 μg/mL, with significant augmentation under hyperthermic conditions. No dose-limiting toxicity occurred in the clinical study. Dose escalation was completed at the final level of OHP. CONCLUSIONS The MMC-5FU-OHP combination showed marked growth inhibition against colorectal cancer cells under hyperthermic conditions in vitro. In the phase I study, the recommended dose of OHP was determined as 130 mg/m² when used with MMC and 5FU; HIPEC using MMC-5FU-OHP appears to be safe and feasible for patients at high risk of colorectal peritoneal metastasis.

Real-Time Magnetic Resonance-Guided Microwave Coagulation Therapy for Pelvic Recurrence of Rectal Cancer: Initial Clinical Experience Using a 0.5 T Open Magnetic Resonance System

PURPOSE: This study aims to evaluate consecutive cases of recurrent rectal cancer in the pelvic cavity treated with microwave coagulation therapy using real-time navigation by an open magnetic resonance system. METHODS: Nine recurrent pelvic lesions in 8 patients after curative resection of rectal cancer were treated with real-time magnetic resonance-guided microwave coagulation therapy as a palliative local therapy to reduce tumor volume and/or local pain. Clinical and pathological data were collected retrospectively by reviewing medical records and clinical imaging results. RESULTS: Seven patients received other treatments before real-time magnetic resonance-guided microwave coagulation. Six patients had distant synchronous metastases. Three patients underwent surgery under lumbar anesthesia. Microwave coagulation was performed percutaneously in 5 lesions and under laparotomy in 4 lesions. Although adverse events related to microwave coagulation (skin necrosis and nerve injury) were observed, no fatal complications occurred. Local re-recurrence was observed in 2 of 9 ablated lesions. Except for 1 patient who died of chronic renal failure, the remaining 7 patients died of cancer. Median overall survival after microwave coagulation for all patients was 10 months (range, 4–37 mo). Median overall survival after discovery of pelvic recurrence in all patients was 22 months (range, 9–42 mo). CONCLUSIONS: The benefits of using an open magnetic resonance system in the pelvic cavity include the abilities to treat tumors that cannot be visualized by other modalities, to demonstrate internal architectural changes during treatment, to differentiate treated vs untreated areas, and to allow adjustments to the treatment plan during the procedure. Additional studies are required to clarify the efficacy of tumor coagulation for local control.