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HER2/neu (HER2) and cyclin E are important prognostic indicators in breast cancer. Since both are involved in cell cycle regulation we investigated whether there was a direct interaction between the two. HER2 and cyclin E expression levels were determined in 395 breast cancer patients. Patients with HER2-overexpression and high levels of cyclin E had decreased 5-year disease-specific survival compared with low levels of cyclin E (14% versus 89%, P < .0001) In vitro studies were performed in which HER2-mediated activity in HER2-overexpressing breast cancer cell lines was downregulated by transfection with HER2 siRNA or treatment with trastuzumab. Cyclin E expression levels were determined, and functional effects investigated using kinase assays, MTT assays to assess cell viability as a marker of proliferation, and FACS analysis to determine cell cycle profiles. Decreased HER2-mediated signaling resulted in decreased expression of cyclin E, particularly the low molecular weight (LMW) isoforms. Decreased HER2 and LMW cyclin E expression had functional effects, including decreased cyclin E-associated kinase activity and decreased proliferation, due to increased apoptosis and an increased accumulation of cells in the G1 phase. In vivo studies performed in a HER2-overexpressing breast cancer xenograft model confirmed the effects of trastuzumab on cyclin E expression. Given the relationship between HER2 and cyclin E, in vitro clonogenic assays were performed to assess combination therapy targeting both proteins. Isobologram analysis showed a synergistic interaction between the two agents (trastuzumab targeting HER2 and roscovitine targeting cyclin E). Taken together, these studies demonstrate that HER2-mediated signaling effects LMW cyclin E expression, which in turn effects cell cycle regulation. LMW cyclin E has prognostic and predictive roles in HER2-overexpressing breast cancer, warranting further study of its potential as a therapeutic target.

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Objective: The combination of docetaxel (DTX) with Laser-Activated NanoTherapy (LANT), as a treatment for head and neck cancer (HNC) may enhance the therapeutic efficacy of lower doses of DTX, thereby minimizing the effective dosage, side effects and treatment times. Material and methods: Three HNSCC cell lines, Detroit 562, FaDu, and CAL 27, were treated with four combinations of DTX + LANT to evaluate DTX dose reduction and cell viability. Results: The 1 nM DTX + 5 nM LANT combination was the most effective treatment, increasing cell death over its corresponding DTX monotreatment with approximately 86.6%, 80.7%, and 92.1% cell death for Detroit 562, FaDu, and CAL 27, respectively. In Detroit 562, the 1 nM DTX + 5 nM LANT combination treatment resulted in the highest percentage of DTX dose reduction at 84.6%; in FaDu and CAL 27, the 0.5 nM DTX + 5 nM LANT combination treatment resulted in the highest percentage of DTX dose reduction at 78.2% and 82.4%, respectively. Conclusion: LANT may increase the therapeutic efficacy of DTX at significantly lower doses, which could improve patient outcomes.

Objective: The combination of docetaxel (DTX) with Laser-Activated NanoTherapy (LANT), as a treatment for head and neck cancer (HNC), may enhance the therapeutic efficacy of lower doses of DTX, thereby minimizing the effective dosage, side effects and treatment times. Material and methods: Three HNSCC cell lines, Detroit 562, FaDu, and CAL 27, were treated with four combinations of DTX + LANT to evaluate DTX dose reduction and cell viability. Results: The 1 nM DTX + 5 nM LANT combination was the most effective treatment, increasing cell death over its corresponding DTX monotreatment with approximately 86.6%, 80.7%, and 92.1% cell death for Detroit 562, FaDu, and CAL 27, respectively. In Detroit 562, the 1 nM DTX + 5 nM LANT combination treatment resulted in the highest percentage of DTX dose reduction at 84.6%; in FaDu and CAL 27, the 0.5 nM DTX + 5 nM LANT combination treatment resulted in the highest percentage of DTX dose reduction at 78.2% and 82.4%, respectively. Conclusion: LANT may increase the therapeutic efficacy of DTX at significantly lower doses, which could improve patient outcomes.

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