Clin Cancer Res
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Clinical Trial
Phase I study of doxil-cisplatin combination chemotherapy in patients with advanced malignancies.
Our first objective was to evaluate the feasibility of administering a combination of Doxil, a pegylated liposome formulation of doxorubicin, and cisplatin and to determine the maximum tolerated dose of the combination. A secondary objective was to examine Doxil peak and 7-day postinjection plasma levels at the various dose levels tested. ⋯ Doxil can be administered at full maximum tolerated dose (50 mg/m(2) every 4 weeks) in combination with 60 mg/m(2) cisplatin, with no evidence of major overlapping toxicities. Palmar-plantar erythrodysesthesia incidence and severity appears to be diminished, in comparison with data available for single-agent Doxil. Plasma concentration data point to an accelerated clearance of Doxil when administered after cisplatin.
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Matrix metalloproteinases (MMPs) degrade components of the extracellular matrix and are implicated in tissue remodeling and tumor infiltration. Tissue inhibitor of metalloproteinases (TIMPs) inhibit enzymes of the MMP family and preserve stromal integrity, thus inhibiting tumor migration. Although numerous studies on several human carcinomas have demonstrated a role for MMPs in tumor metastasis and patient survival, their prognostic role in patients with renal cell carcinoma (RCC) has not been well defined. More importantly, the recently documented paradoxical functions of TIMPs have not been characterized in these neoplasms. ⋯ Increased expression of MMP2, MMP9, TIMP1, and TIMP2 proteins in RCCs correlate with poor prognostic variables including shortened patient survival. The paradoxical poor prognostic implication of TIMP overexpression complements the recently documented dual function of TIMPs and warrants further investigation.
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Topotecan is a topoisomerase (Topo) I inhibitor used in ovarian carcinoma chemotherapy. Topo I inhibitors are thought to be more cytotoxic using protracted schedules of administration. We tested this hypothesis on a preclinical model: human ovarian carcinoma OVCAR-3 implanted i.p. ⋯ Finally, Topo I activity was monitored in ascites from animals treated with different topotecan administration schedules. The optimal schedule defined above allowed for sustained inhibition of Topo I activity associated with a greater antitumor activity. These in vivo data constitute a rationale for clinical studies testing this type of administration.
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It has been proposed that Cyclooxygenase (COX)-2 inhibitors may be able to enhance the effects of chemotherapeutic or radiation treatment; however, currently few studies have been reported that define the radiation-enhancing effect of COX-2 inhibitors. We conducted in vitro radiation survival experiments using rat intestinal epithelial cells which were stably transfected with COX-2 cDNA in the sense (RIE-S) and antisense (RIE-AS) orientations to investigate the potential radiosensitizing effect of the selective COX-2 inhibitor, NS-398. Apoptosis was measured using 7-aminoactinomycin-D with flow cytometry to investigate underlying mechanisms for the effect of NS-398 on radiosensitivity. ⋯ These in vitro and in vivo results suggest that selective COX-2 inhibitors enhance the effect of radiation on tumors that express COX-2 but not on COX-2-lacking tumors. This effect may be attributable to enhancement of radiation-induced apoptosis. Thus, selective COX-2 inhibitors may have potential as radiosensitizers for treatment of human cancers.
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Temozolomide (TMZ) is a methylating agent of the imidotetrazine class, whose cytotoxic product is O(6)-methylguanine DNA adducts, which initiate a futile recycling of the mismatch repair pathway causing DNA strand breaks and apoptotic cell death in mismatch repair proficient cells. The DNA repair protein O(6)-alkylguanine DNA alkyltransferase (AGT) repairs these adducts in a suicide manner and reduces the cytotoxic action of TMZ. An antitumor threshold is reached when sufficient adducts are formed by TMZ to inactivate AGT. ⋯ Five additional patients achieved prolonged stabilization of disease for 4-6 monthly cycles. This is the first study to document that at maximum tolerated doses, TMZ depletes PBMC AGT but only partially and variably depletes visceral tumor AGT in most patients, even during twice daily dosing. Drug combinations or schedules designed to maximally deplete tumor AGT might improve TMZ efficacy.