Production of interleukin 15 by human colon cancer cells is associated with induction of mucosal hyperplasia, angiogenesis, and metastasis.

PURPOSE: The purpose of this study was to identify a mediator produced by human colon cancer cells that is responsible for the induction of hyperplasia in the adjacent mucosa. EXPERIMENTAL DESIGN: Seventy human colon cancer surgical specimens were immunostained to determine the presence of cytokines that can induce hyperplasia in the adjacent mucosal. Human colon cancer cells with low and high metastatic potential were implanted into the cecal wall of nude mice. The resulting lesions were studied by immunohistochemistry to detect possible mediators of mucosal hyperplasia. RESULTS: Immunostaining of 70 colon cancer specimens from 70 patients suggested that mucosal hyperplasia and distant metastasis were associated with the expression of interleukin (IL)-15 and, to a lesser extent, transforming growth factor alpha. The production of IL-15 by colon cancer cells was not associated with the infiltration of natural killer cells into the tumors. Cecal tumors produced in nude mice by human colon cancer cells with low and high metastatic potential (KM12C and KM12SM cells, respectively) expressed similar levels of transforming growth factor alpha, and expression of IL-15 was detected only in the metastatic KM12SM cells and was associated with hyperplasia of the surrounding mucosa. The expression of the IL-15 receptor in rat intestinal epithelial cells (IEC6 cells) was confirmed by immunoblotting with antibodies against IL-15 receptor alpha and IL-2 receptor beta and gamma subunits and by a binding assay using (125)I-labeled IL-15 (K(d) = 0.011 nM). IL-15 stimulated proliferation of the IEC6 cells, even under serum starvation. Treatment of IEC6 cells with IL-15 decreased doxorubicin-mediated cytotoxicity. In IEC6 cells treated with either IL-15- or KM12SM-conditioned medium, immunoblotting revealed a decrease in the production of p21Waf1, Bax, and Bak and an increase in the production of cyclin E, proliferating cell nuclear antigen, the phosphorylated active form of AKT, basic fibroblast growth factor, and vascular endothelial growth factor, changes associated with cell growth, survival, and induction of angiogenesis. CONCLUSIONS: These data indicate that IL-15 produced by metastatic colon carcinoma cells can induce hyperplasia in the mucosa adjacent to colon cancer, thus contributing to angiogenesis and progression of the disease.

Pro-chemotherapeutic effects of antibody against extracellular domain of claudin-4 in bladder cancer.

Bladder cancer displays an aggressive phenotype in the muscle-invasive phase, and is associated with a high mortality rate. Therefore, novel molecular therapeutic targets are needed to improve patient survival. A monoclonal antibody against the extracellular domain of the claudin-4 (CLDN4) tight junction protein was established by immunizing rats with a plasmid vector encoding human CLDN4. A hybridoma clone, producing a rat monoclonal antibody recognizing CLDN4 (clone 4D3), was obtained. Immunohistochemistry by using the 4D3 antibody showed that CLDN4 expression was associated with local invasion, nodal metastasis, distant metastasis, and advanced stage in 86 cases of bladder cancer. The 4D3 antibody inhibited growth, invasion, and survival, associated with abrogation of the intratumoral microenvironment; lowered concentrations of epidermal growth factor and vascular endothelial growth factor were found in three-dimensional cultures of T24 and RT4 cells. In combination with cisplatin therapy, 4D3 enhanced cisplatin cytotoxicity by increasing cellular permeability, leading to increased intracellular cisplatin concentrations. In mouse models of subcutaneous tumors and lung metastasis, 4D3 enhanced tumor growth inhibition, alone and with concurrent cisplatin treatment. The anti-tumor activity of the newly established 4D3 antibody suggests that it may be a powerful tool in CLDN4-targeting therapy, and in combination with chemotherapy.

Two rare metachronous metastases of hepatocellular carcinoma after liver transplantation.

A 59-year-old male with hepatocellular carcinoma (HCC) due to liver cirrhosis caused by the hepatitis C virus underwent cadaveric whole liver transplantation. Two years later, he had a metastatic HCC in the superior mediastinum. Over the following postoperative year, he underwent transcatheter arterial chemoembolization (TACE) for 4 tumors in the implanted liver. In the third post-TACE month, he was emergently hospitalized due to intracerebral hematoma with a tumor invading the bone in the medial frontal segment. He underwent emergency intracranial tumorectomy and hemorrhage removal. The histopathologic diagnosis was metastatic HCC. He regained consciousness as well as the ability to speak and to feed himself, resulting in an improved quality of life. The incidence of HCC recurrence after liver transplantation is observed in approximately 8% to 11% of selected cases, with frequent relapses observed in the implanted liver, bones, adrenal glands, and lungs. Mediastinal and intracranial metastases from HCC post-liver transplantation are very rare.