toremifene and Head-and-Neck-Neoplasms

The effect of toremifene on P-glycoprotein-mediated multidrug resistance (MDR) in breast and head and neck cancer cell lines was measured in vitro and in vivo. Pgp expression was low and high, respectively, in drug-sensitive (MCF7-S, KB) and drug-resistant (MCF7-R, MCF7-R1, KBV1) cell lines. Toremifene (7.5 microM) significantly enhanced cytoplasmic and nuclear accumulation of doxorubicin in drug-resistant cells. Toremifene (10 microM) increased the in vitro cytotoxicity of doxorubicin in drug-resistant breast cancer cells (13-fold and 21-fold for MCF7-R and MCF7-R1, respectively) without affecting the sensitivity of MCF7-S cells. Similarly, toremifene (10 microM) caused a 12-fold increase in the sensitivity of KBV1 cells to vinblastine. In contrast, toremifene (5 microM) reduced the net uptake of the radiolabelled Pgp substrate, Tc-99m-sestamibi, in the Pgp-overexpressing cell lines by factors of 0.32 and 0.42 for MCF7-R1 and KBV1 cells, respectively (p < 0.01), and, to a lesser extent, by corresponding factors of 0.89 and 0.86 in the drug-sensitive cell lines (p < 0.05 and p > 0.05, respectively). In nude mice bearing both KB and KBV1 xenograft tumours, significantly higher tumour levels of Tc-99m-sestamibi were recorded in KB tumours compared with KBV1 tumours. After 3 days of treatment with intraperitoneal toremifene (25 mg/kg), tumour levels of Tc-99m-sestamibi were reduced in KB and KBV1 tumours but only statistically significantly for KB tumours. Toremifene is a potent MDR modulating agent with respect to chemotherapeutic agents but has the opposite effect with respect to Tc-99m-sestamibi. This finding is of importance in view of the widespread use of Tc-99m-sestamibi as an imaging surrogate for a chemotherapeutic agent.

Topics: Animals; ATP Binding Cassette Transporter, Subfamily B, Member 1; Breast Neoplasms; Cell Line, Tumor; Doxorubicin; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Female; Head and Neck Neoplasms; Humans; Immunohistochemistry; Mice; Microscopy, Fluorescence; Technetium Tc 99m Sestamibi; Toremifene; Vinblastine

Aggressive fibromatosis is a rare, benign tumour with a capacity for infiltration of surrounding structures and a propensity for local recurrence. The cornerstone of therapy is surgery, with various other treatment modalities having ill-defined roles. Assessment of the efficacy of these interventions is difficult. The natural history of the condition is variable and different treatment modalities are often used concurrently. Childhood cases pose particular management problems because of their tendency to occur in the head and neck region and the potential for treatment-related morbidity. Two children presented after surgery with recurrent disease threatening the airway. One remitted spontaneously and remains disease free at 20 years. The other achieved a complete remission with radiotherapy and toremifene. The role of non-surgical treatment, particularly radiotherapy, is reviewed.

Topics: Adolescent; Antineoplastic Agents, Hormonal; Child, Preschool; Fibromatosis, Aggressive; Head and Neck Neoplasms; Humans; Male; Neoplasm Recurrence, Local; Toremifene; Torticollis; Treatment Outcome