tirapazamine and Neoplasm-Metastasis

A phase II study was undertaken to determine the efficacy of tirapazamine combined with cisplatin in patients with metastatic melanoma between April 1996 and April 1997. Tirapazamine 390 mg/m2, administered i.v. over 2 h, followed in 1 h by cisplatin 75 mg/m2 over 1 h, were used every 21 days to treat chemotherapy-naive patients with metastatic melanoma. Objective tumor measurements were used to assess efficacy of the regimen. NCI common toxicity criteria were used to grade toxicities. Forty-eight patients with metastatic melanoma of cutaneous or mucosal origin, none with symptomatic brain metastasis, were treated. Nine patients had a partial response, with an overall response rate of 20% (95% confidence interval: 9-33%). The median duration of response was 6 months. Grade 3 nausea, vomiting, anorexia, muscle cramps and fatigue occurred in fewer than 10% of patients. Neutropenia and thrombocytopenia were rare. This outpatient single-day administered tirapazamine-cisplatin regimen has definite activity in chemotherapy-naive patients with metastatic melanoma. Further studies in combination with other agents active against this disease are warranted.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Cisplatin; Dose-Response Relationship, Drug; Female; Humans; Male; Melanoma; Middle Aged; Neoplasm Metastasis; Neoplasm Staging; Time Factors; Tirapazamine; Treatment Outcome; Triazines

Hypoxia-activated prodrugs (HAPs) have the potential to selectively kill hypoxic cells and convert tumor hypoxia from a problem to a selective treatment advantage. However, HAPs are unsuccessful in most clinical trials owing to inadequate hypoxia within the treated tumors, as implied by a further substudy of a phase II clinical trial. Here, a novel strategy for the combination of HAPs plus vascular disrupting agent (VDA) nanomedicine for efficacious solid tumor therapy is developed. An effective VDA nanomedicine of poly(l-glutamic acid)-graft-methoxy poly(ethylene glycol)/combretastatin A4 (CA4-NPs) is prepared and can selectively enhance tumor hypoxia and boost a typical HAP tirapazamine (TPZ) therapy against metastatic 4T1 breast tumors. After treatment with the combination of TPZ plus CA4-NPs, complete tumor reduction is observed in 4T1 xenograft mice (initial tumor volume is 180 mm

Topics: Animals; Breast Neoplasms; Cell Line, Tumor; Drug Synergism; Mice; Mice, Inbred BALB C; Nanomedicine; Neoplasm Metastasis; Prodrugs; Stilbenes; Tirapazamine; Tumor Hypoxia; Xenograft Model Antitumor Assays

Tumor resistance to ionizing irradiation and cancer cell's metastasis stimulated by radiation often lead to anti-cancer failure, and can be negatively caused by a key role--cellular hypoxia. In this regard, the exploitation of hypoxia-specific cytotoxic agents which assist to potentiate the anti-tumor effect of radiotherapy (RT) as well as efficiently counteract radiation-/hypoxia-induced cancer cell metastasis, becomes especially important, but has been widely overlooked. Herein, a core/shell-structured multifunctional nanoradiosensitizer with upconversion nanoparticle (UCNP) as an inside core, mesoporous silica as the shell and a cavity in between, has been constructed, in which UCNP core serves as radiation dose amplifiers and bio-reductive pro-drug--tirapazamine (TPZ) loaded in cavity is an hypoxia-selective cytotoxin and the silica shell provides the protection and diffusion path for TPZ. Such nanoradiosensitizer has been employed to inhibit the hypoxia-reoxygenation and the subsequent replication of cancer cells that often occurs after a single unaccompanied RT at low doses, and to silence the expression of transcription factors that support the progression of malignancy in cancer. This study confirms the radiotherapeutic benefits of utilizing nanoradiosensitizer as adjuvant to low-dose RT, and the results demonstrate the highly efficient hypoxia-specific killing in oxygen-dependent anti-tumor therapies.

Topics: Animals; Cell Death; Cell Proliferation; Cell Survival; Extracellular Matrix; Female; Fluorescent Antibody Technique; HeLa Cells; Humans; Hypoxia; Mice, Inbred BALB C; Mice, Nude; Nanoparticles; Neoplasm Metastasis; Neoplasms; Oxygen; Radiation-Sensitizing Agents; Tirapazamine; Triazines

To evaluate the usefulness of combined treatment with continuous administration of a hypoxic cytotoxin, tirapazamine (TPZ), and mild temperature hyperthermia (MTH) in γ-ray irradiation in terms of local tumour response and lung metastatic potential, referring to the response of intratumour quiescent (Q) cells.. B16-BL6 melanoma tumour-bearing C57BL/6 mice were continuously given 5-bromo-2'-deoxyuridine (BrdU) to label all proliferating (P) cells. The tumour-bearing mice then received γ-ray irradiation after a single intraperitoneal injection or 24 h continuous subcutaneous infusion of TPZ, either with or without MTH. Immediately after the irradiation, cells from some tumours were isolated and incubated with a cytokinesis blocker. The responses of the Q and total (= P + Q) cell populations were assessed based on the frequency of micronuclei using immunofluorescence staining for BrdU. In other tumour-bearing mice, 17 days after irradiation, macroscopic lung metastases were enumerated.. Continuous administration elevated the sensitivity of both the total and Q cells, especially the total cells. MTH raised the sensitivity of Q cells more remarkably in both single and continuous administrations, probably because of more exposure to TPZ in intermediately hypoxic areas derived mainly from chronic hypoxia through MTH. With or without irradiation, TPZ, especially administered continuously and combined with MTH, decreased the number of lung metastases.. The combination of continuous long-term administration of TPZ and MTH in γ-ray irradiation was thought to be promising because of its potential to enhance local tumour response and repress lung metastatic potential.

Topics: Animals; Antineoplastic Agents; Combined Modality Therapy; Female; Gamma Rays; Hyperthermia, Induced; Lung Neoplasms; Melanoma, Experimental; Mice; Mice, Inbred C57BL; Neoplasm Metastasis; Tirapazamine; Triazines; Tumor Burden

Metastases cause most cancer-related deaths. We investigated the use of hypoxia-selective cytotoxins as adjuvants to radiotherapy in the control of metastatic tumour growth.. The NLCQ-1, RB6145 and tirapazamine were assessed against the spontaneously metastasising KHT model. Subcutaneous KHT tumours (250 mm(3)) were irradiated with 25 Gy (single fraction) to control primary growth. Equitoxic drug treatments (NLCQ-1 (10 mg kg(-1)) once daily; RB6145 (75 mg kg(-1)) and tirapazamine (13 mg kg(-1)) twice daily) were administered 3-6 days post-radiotherapy when hypoxic cells were evident in lung micrometastases. Mice were culled when 50% of controls exhibited detrimental signs of lung metastases.. In total, 95% of control mice presented with lung disease. This was significantly reduced by NLCQ-1 (33%; P=0.0002) and RB6145 (60%; P=0.02). Semi-quantitative grading of lung disease revealed a significant improvement with all treatments, with NLCQ-1 proving most efficacious (median grades: control, 4; NLCQ, 0 (P<0.0001); RB6145, 1 (P<0.001), tirapazamine, 3 (P=0.007)). Positron emission tomography (PET) was evaluated as a non-invasive means of assessing metastatic development. Primary and metastatic KHT tumours showed robust uptake of [(18)F]fluorodeoxyglucose ([(18)F]FDG). Metastatic burden discernable by [(18)F]FDG PET correlated well with macroscopic and histological lung analysis.. The hypoxia-selective cytotoxin NLCQ-1 controls metastatic disease and may be a successful adjuvant to radiotherapy in the clinical setting.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Cell Hypoxia; Cell Line, Tumor; Chemotherapy, Adjuvant; Combined Modality Therapy; Drug Administration Schedule; Drug Evaluation, Preclinical; Imidazoles; Lung Neoplasms; Mice; Mice, Inbred C3H; Neoplasm Metastasis; Nitroimidazoles; Quinolines; Sarcoma; Tirapazamine; Triazines

The level of hypoxia in primary tumors has been linked both clinically and experimentally to the incidence of metastases. This study was designed to address the effect of selectively targeting hypoxic cells in primary tumors on subsequent presentation of metastasis.. The murine KHT model was used as a reproducible temporal and spatial onset of metastases is revealed following treatment of primary ( approximately 400 mm(3)) s.c. tumors with a 25 Gy radiation dose. The bioreductive drugs tirapazamine and RB6145 were administered in multiple doses before radiotherapy.. Fractionated treatment with both tirapazamine and RB6145 significantly reduced the hypoxic fraction of the primary tumor, as assessed by pimonidazole binding, and had no effect on the overall growth rate of the primary tumor. Excision assays showed an increased level of cell kill in tirapazamine-treated versus RB6145-treated tumors consistent with tirapazamine targeting hypoxic cells at a broader range of oxygen tensions than RB6145. Tirapazamine treatment significantly reduced the presentation of metastases following radiotherapy (P = 0.003 versus saline controls) whereas RB6145 had no effect. Local control rates increased from 20% to 32% and 50% when radiation was combined with RB6145 and tirapazamine, respectively.. These data provide direct evidence that selective targeting of hypoxic cells in primary tumors is a viable approach in the control of metastatic disease. The enhanced efficacy of tirapazamine versus RB6145 suggests that the radioresistant cells at intermediate oxygen tensions, conducive to targeting with tirapazamine but not with the more stringent bioreductive RB6145, predominate in terms of linking primary tumor hypoxia and metastases.

Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Combined Modality Therapy; Female; Hypoxia; Mice; Mice, Inbred C3H; Neoadjuvant Therapy; Neoplasm Metastasis; Neoplasm Transplantation; Neovascularization, Pathologic; Nitroimidazoles; Radiation-Sensitizing Agents; Sarcoma, Experimental; Tirapazamine; Treatment Outcome; Triazines