24 research outputs found

    Mutations in the PKM2 exon-10 region are associated with reduced allostery and increased nuclear translocation.

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    PKM2 is a key metabolic enzyme central to glucose metabolism and energy expenditure. Multiple stimuli regulate PKM2's activity through allosteric modulation and post-translational modifications. Furthermore, PKM2 can partner with KDM8, an oncogenic demethylase and enter the nucleus to serve as a HIF1α co-activator. Yet, the mechanistic basis of the exon-10 region in allosteric regulation and nuclear translocation remains unclear. Here, we determined the crystal structures and kinetic coupling constants of exon-10 tumor-related mutants (H391Y and R399E), showing altered structural plasticity and reduced allostery. Immunoprecipitation analysis revealed increased interaction with KDM8 for H391Y, R399E, and G415R. We also found a higher degree of HIF1α-mediated transactivation activity, particularly in the presence of KDM8. Furthermore, overexpression of PKM2 mutants significantly elevated cell growth and migration. Together, PKM2 exon-10 mutations lead to structure-allostery alterations and increased nuclear functions mediated by KDM8 in breast cancer cells. Targeting the PKM2-KDM8 complex may provide a potential therapeutic intervention

    KDM4B is a coactivator of c-Jun and involved in gastric carcinogenesis

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    Abstract KDM4/JMJD2 Jumonji C-containing histone lysine demethylases (KDM4A–D) constitute an important class of epigenetic modulators in the transcriptional activation of cellular processes and genome stability. Interleukin-8 (IL-8) is overexpressed in gastric cancer, but the mechanisms and particularly the role of the epigenetic regulation of IL-8, are unclear. Here, we report that KDM4B, but not KDM4A/4C, upregulated IL-8 production in the absence or presence of Helicobacter pylori. Moreover, KDM4B physically interacts with c-Jun on IL-8, MMP1, and ITGAV promoters via its demethylation activity. The depletion of KDM4B leads to the decreased expression of integrin αV, which is exploited by H. pylori carrying the type IV secretion system, reducing IL-8 production and cell migration. Elevated KDM4B expression is significantly associated with the abundance of p-c-Jun in gastric cancer and is linked to a poor clinical outcome. Together, our results suggest that KDM4B is a key regulator of JNK/c-Jun-induced processes and is a valuable therapeutic target

    Apoptotic and Nonapoptotic Activities of Pterostilbene against Cancer

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    Cancer is a major cause of death. The outcomes of current therapeutic strategies against cancer often ironically lead to even increased mortality due to the subsequent drug resistance and to metastatic recurrence. Alternative medicines are thus urgently needed. Cumulative evidence has pointed out that pterostilbene (trans-3,5-dimethoxy-4-hydroxystilbene, PS) has excellent pharmacological benefits for the prevention and treatment for various types of cancer in their different stages of progression by evoking apoptotic or nonapoptotic anti-cancer activities. In this review article, we first update current knowledge regarding tumor progression toward accomplishment of metastasis. Subsequently, we review current literature regarding the anti-cancer activities of PS. Finally, we provide future perspectives to clinically utilize PS as novel cancer therapeutic remedies. We, therefore, conclude and propose that PS is one ideal alternative medicine to be administered in the diet as a nutritional supplement

    The comparison between weekly and three-weekly cisplatin delivered concurrently with radiotherapy for patients with postoperative high-risk squamous cell carcinoma of the oral cavity

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    Abstract Background The aim of this study was to compare the outcomes of postoperative adjuvant concomitant chemoradiotherapy using two different schedules of cisplatin for patients with high-risk oral squamous cell carcinoma (OSCC). Methods From Feb. 2008 to Aug. 2010, 55 patients with high-risk OSCC were included in this study. Patients were randomized into treatment groups that either received 100 mg/m2 cisplatin once every 3 weeks (arm A) or 40 mg/m2 cisplatin once per week (arm B). All patients were irradiated with 66 Gy in 33 fractions. Results Of the 50 eligible patients, 26 were assigned to arm A, and 24 were assigned to arm B. Both groups of patients received the same mean doses of radiotherapy and cisplatin. However, 88.5% of patients in arm A and 62.5% of those in arm B (p = 0.047) received ≥ 200 mg/m2 of cisplatin in total. The overall toxicity was significantly greater in arm B (p = 0.020), and all of the grade 4 toxicities occurred in patients in arm B. Conclusions Three-weekly high-dose cisplatin treatment showed higher compliance, and lower acute toxicity compared to weekly low-dose cisplatin treatment.</p
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