Browsing by Author "Behbakht, Kian"

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    Claudin-4 remodeling of nucleus-cell cycle crosstalk maintains ovarian tumor genome stability and drives resistance to genomic instability-inducing agents
    (bioRxiv, 2024-09-07) Villagomez, Fabian R.; Lang, Julie; Nunez-Avellaneda, Daniel; Behbakht, Kian; Dimmick, Hannah L.; Webb, Patricia; Nephew, Kenneth P.; Neville, Margaret; Woodruff, Elizabeth R.; Bitler, Benjamin G.; Anatomy, Cell Biology and Physiology, School of Medicine
    During cancer development, the interplay between the nucleus and the cell cycle leads to a state of genomic instability, often accompanied by observable morphological aberrations. These aberrations can be controlled by tumor cells to evade cell death, either by preventing or eliminating genomic instability. In epithelial ovarian cancer (EOC), overexpression of the multifunctional protein claudin-4 is a key contributor to therapy resistance through mechanisms associated with genomic instability. However, the molecular mechanisms underlying claudin-4 overexpression in EOC remain poorly understood. Here, we altered claudin-4 expression and employed a unique claudin-4 targeting peptide (CMP) to manipulate the function of claudin-4. We found that claudin-4 facilitates genome maintenance by linking the nuclear envelope and cytoskeleton dynamics with cell cycle progression. Claudin-4 caused nuclei constriction by excluding lamin B1 and promoting perinuclear F-actin accumulation, associated with remodeling nuclear architecture, thus altering nuclear envelope dynamics. Consequently, cell cycle modifications due to claudin-4 overexpression resulted in fewer cells entering the S-phase and reduced genomic instability. Importantly, disrupting biological interactions of claudin-4 using CMP and forskolin altered oxidative stress cellular response and increased the efficacy of PARP inhibitor treatment. Our data indicate that claudin-4 protects tumor genome integrity by remodeling the crosstalk between the nuclei and the cell cycle, leading to resistance to genomic instability formation and the effects of genomic instability-inducing agents.
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    Randomized phase III trial of gemcitabine plus docetaxel plus bevacizumab or placebo as first-line treatment for metastatic uterine leiomyosarcoma: an NRG Oncology/Gynecologic Oncology Group study
    (American Society of Clinical Oncology, 2015-04-01) Hensley, Martee L.; Miller, Austin; O'Malley, David M.; Mannel, Robert S.; Behbakht, Kian; Bakkum-Gamez, Jamie N.; Michael, Helen; Department of Pathology & Laboratory Medicine, IU School of Medicine
    PURPOSE: Fixed-dose rate gemcitabine plus docetaxel achieves objective response in 35% of patients with uterine leiomyosarcoma (uLMS). This study aimed to determine whether the addition of bevacizumab to gemcitabine-docetaxel increases progression-free survival (PFS) in uLMS. PATIENTS AND METHODS: In this phase III, double-blind, placebo-controlled trial, patients with chemotherapy-naive, metastatic, unresectable uLMS were randomly assigned to gemcitabine-docetaxel plus bevacizumab or gemcitabine-docetaxel plus placebo. PFS, overall survival (OS), and objective response rates (ORRs) were compared to determine superiority. Target accrual was 130 patients to detect an increase in median PFS from 4 months (gemcitabine-docetaxel plus placebo) to 6.7 months (gemcitabine-docetaxel plus bevacizumab). Treatment effects on PFS and OS were described by hazard ratios (HRs), median times to event, and 95% CIs. RESULTS: In all, 107 patients were accrued: gemcitabine-docetaxel plus placebo (n = 54) and gemcitabine-docetaxel plus bevacizumab (n = 53). Accrual was stopped early for futility. No statistically significant differences in grade 3 to 4 toxicities were observed. Median PFS was 6.2 months for gemcitabine-docetaxel plus placebo versus 4.2 months for gemcitabine-docetaxel plus bevacizumab (HR, 1.12; P = .58). Median OS was 26.9 months for gemcitabine-docetaxel plus placebo and 23.3 months for gemcitabine-docetaxel plus bevacizumab (HR, 1.07; P = .81). Objective responses were observed in 17 (31.5%) of 54 patients randomly assigned to gemcitabine-docetaxel plus placebo and 19 (35.8%) of 53 patients randomly assigned to gemcitabine-docetaxel plus bevacizumab. Mean duration of response was 8.6 months for gemcitabine-docetaxel plus placebo versus 8.8 months for gemcitabine-docetaxel plus bevacizumab. CONCLUSION: The addition of bevacizumab to gemcitabine-docetaxel for first-line treatment of metastatic uLMS failed to improve PFS, OS, or ORR. Gemcitabine-docetaxel remains a standard first-line treatment for uLMS.