Microtubule nucleation requires the γ-tubulin ring complex, and during the M phase (mitosis) this complex accumulates at the centrosome to support mitotic spindle formation. The post-translational modification of γ-tubulin through ubiquitination is vital for regulating microtubule nucleation and centrosome duplication. Blocking the BRCA1/BARD1-dependent ubiquitination of γ-tubulin causes centrosome amplification. In the present study, we identified BRCA1 associated protein-1 (BAP1) as a deubiquitination enzyme for γ-tubulin. BAP1 was downregulated in metastatic adenocarcinoma breast cell lines compared to non-cancerous human breast epithelial cells. Furthermore, low expression of BAP1 was associated with reduced overall survival of breast cancer patients. Reduced expression of BAP1 in breast cancer cell lines was associated with mitotic abnormalities. Importantly, rescue experiments including expression of full length but not the catalytic mutant of BAP1 reduced ubiquitination of γ-tubulin and prevented mitotic defects. Our study uncovers a new mechanism for BAP1 involved in deubiquitination of γ-tubulin, which is required to prevent abnormal mitotic spindle formation and genome instability.

Epidemiologic studies linking high serum iron with cancer risks are limited and inconclusive, despite evidence implicating body iron in human carcinogenesis. A cohort of 309,443 adults in Taiwan who had no history of cancer had serum iron levels tested at the time of recruitment (1997–2008). Initially measured iron levels were associated with subsequent cancer risk by linking individuals with the National Cancer Registry and National Death File. HRs were calculated by the Cox model. One third of males (35%) and one fifth of females (18%) had high serum iron (≥120 μg/dL), which was associated with a 25% increase in risk for incidence of all cancers [HR, 1.25; 95% confidence interval (CI), 1.16–1.35] and with a 39% increase in risk for mortality from all cancers (HR, 1.39; 95% CI, 1.23–1.57). The relationship between serum iron and cancer risk was a J-shaped one, with higher cancer risk at both ends, either at lower than 60 μg/dL or higher than 120 μg/dL. At the higher end, cancer risk increased by 4% for every 10 μg/dL increment above 80 μg/dL, showing a dose–response relationship, with 60 to 79 μg/dL as a reference level. In a sensitivity analysis, the increases in risk were still observed after the first 5 years of cancer cases were excluded. Liver cancer risk was increased in HBV (−) non-hepatitis B carrier (3-fold) and HBV (+) hepatitis B carrier (24-fold). Lifestyle risks such as smoking, drinking, or inactivity interacted synergistically with high serum iron and significantly increased the cancer risks. The liver (HR, 2.49; 95% CI, 1.97–3.16) and the breast (HR, 1.31; 95% CI, 1.01–1.70) were the two major cancer sites where significant cancer risks were observed for serum iron either ≥120 μg/dL or ≥140 μg/dL, respectively. This study reveals that high serum iron is both a common disorder and a marker of increased risk for several cancers. Cancer Res; 74(22); 1–9. ©2014 AACR.

Epidemiological studies linking high serum iron with cancer risks are limited and inconclusive, despite evidence implicating body iron in human carcinogenesis. A cohort of 309,443 adults in Taiwan who had no history of cancer had serum iron levels tested at the time of recruitment (1997 – 2008). Initially measured iron levels were associated with subsequent cancer risk by linking individuals with the National Cancer Registry and National Death File. Hazard ratios were calculated by the Cox model. One-third of males (35%) and one-fifth of females (18%) had high serum iron (≧120 μg/dL), which was associated with a 25% increase in risk for incidence of all cancers (Hazard Ratio (HR): 1.25, 95% confidence interval (CI): 1.16-1.35) and with a 39% increase in risk for mortality from all cancers (HR: 1.39, 95% CI: 1.23-1.57). The relationship between serum iron and cancer risk was a J-shaped one, with higher cancer risk at both ends, either at lower than 60 μg/dL or higher than 120 μg/dL. At higher end, cancer risk increased by 4% for every 10 μg/dL increment above 80 μg/dL, showing a dose response relationship, with 60-79 μg/dL as a reference level. In a sensitivity analysis, the increases in risk were still observed after the first five years of cancer cases were excluded. Liver cancer risk was increased in HBV (-) subjects (3-fold) and HBV (+) subjects (24-fold). Lifestyle risks such as smoking, drinking or inactivity interacted synergistically with high serum iron and significantly increased the cancer risks. The risk remained elevated after first 5 years of observation. The liver (HR: 2.98, 95% CI: 2.32-3.84) and the breast (HR: 1.31, 95% CI: 1.01-1.70) were the two major cancer sites where significant cancer risks were observed for serum iron ≧140 μg/dL. This study reveals that high serum iron is both a common disorder and a marker of increased risk for several cancers.

Immune dysregulation drives the pathogenesis of chronic inflammatory, autoimmune, and dysplastic disorders. While often intended to address localized pathology, most immune modulatory therapies are administered systemically and carry inherent risk of multiorgan toxicities. Here, we demonstrate, in a murine model of spontaneous gastrointestinal polyposis, that site-specific uptake of orally administered IL10 microparticles ameliorates local and systemic disease to enhance survival. Mechanistic investigations showed that the therapeutic benefit of this treatment derived from neutralization of disease-promoting FoxP3+RoRγt+IL17+ pathogenic T-regulatory cells (pgTreg), with a concomitant restoration of FoxP3+RoRγt−IL17− conventional T-regulatory cells (Treg). These findings provide a proof-of-principle for the ability of an oral biologic to restore immune homeostasis at the intestinal surface. Furthermore, they implicate local manipulation of IL10 as a tractable therapeutic strategy to address the inflammatory sequelae associated with mucosal premalignancy. Cancer Res; 74(19); 1–9. ©2014 AACR.

Clinical results from the latest strategies for T-cell activation in cancer have fired interest in combination immunotherapies that can fully engage T-cell immunity. In this study, we describe a trastuzumab-based bispecific antibody, HER2-TDB, which targets HER2 and conditionally activates T cells. HER2-TDB specifically killed HER2-expressing cancer cells at low picomolar concentrations. Because of its unique mechanism of action, which is independent of HER2 signaling or chemotherapeutic sensitivity, HER2-TDB eliminated cells refractory to currently approved HER2 therapies. HER2-TDB exhibited potent antitumor activity in four preclinical model systems, including MMTV-huHER2 and huCD3 transgenic mice. PD-L1 expression in tumors limited HER2-TDB activity, but this resistance could be reversed by anti–PD-L1 treatment. Thus, combining HER2-TDB with anti–PD-L1 yielded a combination immunotherapy that enhanced tumor growth inhibition, increasing the rates and durability of therapeutic response. Cancer Res; 74(19); 1–11. ©2014 AACR.