Prevention and treatment of experimental estrogen receptor-negative mammary carcinogenesis by the synthetic triterpenoid CDDO-methyl Ester and the rexinoid LG100268

PURPOSE: To test whether the triterpenoid 2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oic acid methyl ester (CDDO-Me) and the rexinoid LG100268 (268) prevent the formation of estrogen receptor (ER)-negative mammary tumors or either arrest the growth or cause regression of established tumors in MMTV-neu mice. EXPERIMENTAL DESIGN: For prevention, mice were fed control diet, CDDO-Me (60 mg/kg diet), 268 (20 mg/kg diet), or the combination for 45 weeks. For treatment, mice with established tumors at least 4 mm in diameter were fed control diet, CDDO-Me (100 mg/kg diet), 268 (60 mg/kg diet), or the combination for 4 weeks. RESULTS: CDDO-Me and 268 significantly delayed the development of ER-negative tumors, with a 14- and 24-week delay, respectively, compared with the control group for the time required to reach 50% tumor incidence. The combination of CDDO-Me and 268 was significantly more potent than the individual drugs, as only one tumor was found in the combination group, after 45 weeks on diet, at which time all control animals had tumors. Treating established tumors with CDDO-Me arrested the growth of 86% of the tumors, and 268 induced tumor regression in 85% of tumors. CDDO-Me and 268 target different signaling pathways and cell types. CDDO-Me inhibited constitutive STAT3 phosphorylation and the degradation of IKBalpha in ER-negative breast cancer cells, whereas 268 blocked IKBalpha degradation and the release of interleukin-6 in RAW264.7 macrophage-like cells, inhibited the ability of endothelial cells to organize into networks, and blocked angiogenesis in vivo. CONCLUSIONS: CDDO-Me and 268 are useful as individual drugs to prevent ER-negative mammary tumorigenesis and to treat established tumors. They synergize when used in combination for prevention.     

Comparative assessment of TCRBV diversity in T lymphocytes present in blood, metastatic lesions, and DTH sites of two melanoma patients vaccinated with an IL-7 gene-modified autologous tumor cell vaccine

A phase I clinical trial using autologous, IL-7 gene-modified tumor cells in patients with disseminated melanoma has been recently completed. Although no major clinical responses were observed, increased antitumor cytotoxicity was measured in postvaccine peripheral blood lymphocytes in a subset of treated patients. To analyze the in situ immune response, the T cell receptor beta-chain variable region (BV) repertoire of T cells infiltrating postvaccine lesions was studied in two patients, and compared with that of T cells present in prevaccine ones, in peripheral blood lymphocytes, and, in one patient, in delayed type hypersensitivity (DTH) sites of autologous melanoma inoculum. A relative expansion of T cells expressing few BVs was observed in all postvaccine metastases, and their intratumoral presence was confirmed by immunohistochemistry. Length pattern analysis of the complementarity determining region 3 (CDR3) indicated that the repertoire of T cells expressing some of these BVs was heterogeneous. At difference, CDR3, beta-chain joining region usage, and sequence analysis enabled us to demonstrate, within a T-cell subpopulation commonly expanded at DTH sites and at the postvaccine lesion of patient 1, that both DTH sites contained identical dominant T-cell clonotypes. One of them was also expressed at increased relative frequency in the postvaccine lesion compared to prevaccine specimens. These results provide evidence for immunological changes, including in situ clonally expanded T cells, in metastases of patients vaccinated with IL-7 gene-transduced cells.     

Vinorelbine in previously treated advanced childhood sarcomas: evidence of activity in rhabdomyosarcoma

BACKGROUND: Vinca alkaloids have proved active against a number of pediatric malignancies. The aim of this study was to assess the feasibility and effectiveness of using vinorelbine in previously treated pediatric patients with advanced sarcomas. METHODS: From September 1998 to August 2001, 33 previously treated patients with progressive sarcoma were treated: 13 had rhabdomyosarcomas, 5 had other soft tissue sarcomas, 9 had Ewing sarcomas, and 6 had osteosarcomas. Vinorelbine was given intravenously on Days 1 and 8 of a 21-day treatment cycle. Four patients with uncontrolled pain or central nervous system invasion received concurrent radiotherapy and were only evaluated for toxicity. RESULTS: One hundred seventy-eight treatment cycles were administered (median of four per patient, range 1-20). Grade 3 to 4 neutropenia occurred in 63% of patients, Grade 3 anemia in 9%, and Grade 3 thrombocytopenia in 3%. Nonhematological toxicity was mild or moderate, i.e., always lower than Grade 3, with the exception of one child who experienced paralytic ileus. Twenty-eight patients were assessable for response. Eight patients had a partial response, one patient had a minor response, and nine patients had stable disease. Objective responses were observed in 6 of 12 patients with rhadbomyosarcomas (five of six of the alveolar subtype), in one of five patients with osteosarcomas, and in one of seven patients with Ewing sarcomas. The median duration of response was 10 months (range, 3+ to 20). CONCLUSIONS: Vinorelbine has a favorable toxicity profile with evidence of biological activity in already heavily treated pediatric patients with sarcomas. In particular, the objective response rate obtained for patients with alveolar rhabdomyosarcoma seems very promising. Due to the few cases considered here, further Phase II studies are needed to establish a potential role of vinorelbine in the treatment of these tumors.     

The rat tyrosine phosphatase eta increases cell adhesion by activating c-Src through dephosphorylation of its inhibitory phosphotyrosine residue

The expression of the receptor protein tyrosine phosphatase r-PTPeta is drastically reduced in rat and human malignant thyroid cells, whereas its restoration reverts the neoplastic phenotype of retrovirally transformed rat thyroid cells. Moreover, reduced levels and loss of heterozygosity of DEP-1, the human homolog of r-PTPeta, have been found in many human neoplasias. Here, we report that the r-PTPeta protein binds to c-Src in living cells and dephosphorylates the c-Src inhibitory tyrosine phosphorylation site (Tyr 529), thereby increasing c-Src tyrosine kinase activity in malignant rat thyroid cells stably transfected with r-PTPeta. Tyrosine phosphorylation of focal adhesion kinase (FAK) and paxillin was enhanced in r-PTPeta-expressing cells. This was associated with increased adhesion of malignant r-PTPeta-transfected thyroid cells vs both untransfected cells and cells stably transfected with an inactive r-PTPeta mutant. Treatment of rat thyroid cells with the c-Src inhibitor PP2 decreased cell adhesion to a higher extent in r-PTPeta-transfected cells than in mock-transfected or stably transfected cells with the inactive r-PTPeta mutant, indicating that r-PTPeta regulates cell-substratum adhesion by activating c-Src. Interestingly, the extent of both c-Src dephosphorylation at Tyr 529, FAK and paxillin phosphorylation, and the increased cell adhesion were associated with the degree of r-PTPeta expression.