In vivo evidence of htid suppressive activity on ErbB-2 in breast cancers over expressing the receptor.

BACKGROUND: Htid encoded proteins are physiological partners of a wide spectrum of molecules relevant to neoplastic transformation. One of the molecular ligands of the cytosolic hTid-L and hTid-I forms is the ErbB-2 receptor variably over expressed in diverse solid tumors. Altered ErbB-2 signalling is associated with an unfavourable prognosis in about 30% of human breast malignancies. METHODS: We evaluated htid and HER-2 expression by quantitative real time PCR in tumors of different TNMG status and by immunohistochemistry in a cohort of breast tumors of the Luminal A, B, HER-2 and triple negative subtype. RESULTS: The RT-PCR analysis revealed that aberrant expression of all three htid forms correlates with malignant transformation. Furthermore, elevated hTid-L expression can be associated with less aggressive tumors. The immunohistochemical testing revealed that tumors of the luminal A subtype are characterized by a high level of htid (81%). In contrast htid expression is significantly lower in tumors of the Luminal B (20%) and HER-2 (18%) subtype over expressing the receptor and in the triple negative (40%) more aggressive malignancies. A statistically significant inverse correlation between htid and ErbB-2 expression was found in human breast (p < 0,0001) and non-mammary tumors (p < 0,007), and in transgenic mice carrying the rat HER-2/neu oncogene. CONCLUSIONS: Our findings provide in vivo evidence that htid is a tissue independent and evolutionarily conserved suppressor of ErbB-2.

Antitumor efficacy of bcl-2 and c-myc antisense oligonucleotides in combination with cisplatin in human melanoma xenografts: relevance of the administration sequence.

PURPOSE: bcl-2 and c-myc oncogenes are frequently overexpressed in different human tumors, including melanoma. Here, we evaluate the combined efficacy of two antisense oligonucleotides targeting bcl-2 mRNA (ODN bcl-2) and c-myc mRNA (ODN c-myc) in combination with cis-diammine dichloroplatinum (cisplatin, DDP) on three human melanoma lines (LM, NG, and M20). EXPERIMENTAL DESIGN: Two different sequences were designed to treat tumor-bearing mice: in the first one, ODN bcl-2 at a dose of 0.2 mg/day x4, followed by DDP given i.p. at a dose of 3.3 mg/kg/day x3 and ODN c-myc i.v. at 0.5 mg/day x7, whereas the other sequence consisted of ODN c-myc given as first agent followed by DDP and ODN bcl-2 at the same doses. Mice received three complete cycles of treatment in 1-week intervals. RESULTS: The treatment sequence with ODN bcl-2/DDP/ODN c-myc combination completely inhibited growth in NG tumor and induced a 35-day delay in LM tumor growth. In contrast, the M20 tumor growth was unaffected by the combination. A discrete amount of c-Myc and bcl-2 protein expression in both LM and NG tumors was detected, whereas no detectable levels of the two proteins were observed in M20 tumors. Compared with the other combination, the sequence (ODN bcl-2/DDP/ODN c-myc) produced the most effective results, producing a significant decrease in bcl-2 and c-Myc protein expression, which in turn significantly increased the survival of NG- and LM-bearing mice, with 4 mice out of 11 and 1 out of 7 mice being cured, respectively. Finally, this combination increased the apoptotic rate and produced an antiangiogenetic effect. CONCLUSIONS: These results show that an antisense approach to the treatment of melanoma xenografts overexpressing either bcl-2 or c-myc oncogenes represents a successful strategy to improve the response to chemotherapy in melanoma, with particular attention to the treatment sequence.

Protective features of monoclonal antibodies to Escherichia coli during experimental infection of mice with homologous and heterologous serotypes of E. coli.

Murine monoclonal antibodies (MAbs) MT1F and ARM1-4, recognising proteins on the surface of untreated Escherichia coli O6:K-, protected 100% of mice challenged intraperitoneally with 2 x LD50 of the same strain. MAb MT1F protected 70% of animals challenged with 2 x LD50 of E. coli O111:B4, whereas ARM1-4 gave complete protection. Lower survival was observed in mice given either MAb and challenged with E. coli O128:K-, with values ranging from 30 to 42%. However, the protection afforded against E. coli O111:B4 and E. coli O128:K- was significantly improved when the mice were pre-treated with a mixture of the two MAbs. Control mice, pre-treated with unrelated ascitic fluid and challenged with any of the E. coli serotypes, showed 100% mortality and organ histological lesions resembling those of the early stages of septic shock. The mice had high levels of circulating endotoxin and tumour necrosis factor-alpha (TNF-alpha) at 90 min after challenge. In contrast, mice treated with MAbs and surviving the infection displayed moderate histological lesions, enhanced bacterial clearance and lower serum levels of TNF-alpha, despite circulating endotoxin levels that were higher than in the control group. Protection by the MAbs was probably due to the prevention of the bacterial spread to organs and of the cascade of events leading to septic shock. This occurred in spite of the presence of high levels of circulating endotoxin.