Vertical inhibition of the PI3K/Akt/mTOR pathway is synergistic in breast cancer.

Deregulation and activation of the phosphoinositide 3-kinase (PI3K)/Akt/mammalian (or mechanistic) target of rapamycin (mTOR) pathway have a major role in proliferation and cell survival in breast cancer. However, as single agents, mTOR inhibitors have had modest antitumor efficacy. In this study, we evaluated the effects of vertical inhibition of mTOR and Akt in breast cancer cell lines and xenografts. We assessed the effects of mTOR inhibitor rapamycin and Akt inhibitor MK-2206, given as single drugs or in combination, on cell signaling, cell proliferation and apoptosis in a panel of cancer cell lines in vitro. The antitumor efficacy was tested in vivo. We demonstrated that MK-2206 inhibited Akt phosphorylation, cell proliferation and apoptosis in a dose-dependent manner in breast cancer cell lines. Rapamycin inhibited S6 phosphorylation and cell proliferation, and resulted in lower levels of apoptosis induction. Furthermore, the combination treatment inhibited phosphorylation of Akt and S6, synergistically inhibited proliferation and induced apoptosis with a higher efficacy. In vivo combination inhibited tumor growth more than either agent alone. Our data suggest that a combination of Akt and mTOR inhibitors have greater antitumor activity in breast cancer cells, which may be a viable approach to treat patients.

Plk1-mediated stabilization of 53BP1 through USP7 regulates centrosome positioning to maintain bipolarity.

Although 53BP1 has been established well as a mediator in DNA damage response, its function in mitosis is not clearly understood. We found that 53BP1 is a mitotic-binding partner of the kinases Plk1 and AuroraA, and that the binding with Plk1 increases the stability of 53BP1 by accelerating its interaction with the deubiquitinase USP7. Depletion of 53BP1 induces mitotic defects such as chromosomal missegregation, misorientation of spindle poles and the generation of extra centrosomes, which is similar phenotype to USP7-knockdown cells. In addition, 53BP1 depletion reduces the levels of p53 and centromere protein F (CENPF), interacting proteins of 53BP1. These phenotypes induced by 53BP1 depletion were rescued by expression of wild-type or phosphomimic mutant 53BP1 but not by expression of a dephosphomimic mutant. We propose that phosphorylation of 53BP1 at S380 accelerates complex formation with USP7 and CENPF to regulate their stability, thus having a crucial role in proper centrosome positioning, chromosomal alignment, and centrosome number.

Association of aldehyde dehydrogenase 1 expression and biologically aggressive features in breast cancer.

UNLABELLED: Aldehyde dehydrogenase 1 (ALDH1) has been regarded as a breast cancer stem cell marker. Several studies have reported that ALDH1 expression is associated with poor prognosis in breast cancer. We aimed, therefore, to determine the prognostic value of ALDH1 expression and its association with several biomarkers in breast cancer tissue using immunohistochemistry. Furthermore, we investigated the characteristics of and differences between cellular and stromal expression of ALDH1. We performed tissue microarray (TMA) analysis of 425 breast cancer tissue samples collected during surgery. Immunohistochemical staining was then performed to measure the expression of ALDH1 and other breast cancer biomarkers. Statistical analysis of the relationship between ALDH1 expression and clinicopathologic characteristics was performed for 390 TMA samples. We found that ALDH1 was expressed in 71 cases (18.2%) in the tumor cells and/or stroma. Of these cases, 38 (9.7%) showed ALDH1 expression in tumor cells and 38 (9.7%) showed ALDH1 expression in the stroma. ALDH1 expression was significantly associated with markers of a poor prognosis, such as young age, estrogen receptor negativity, progesterone receptor negativity, a high histological grade, and a high Ki-67 index. However, ALDH1 expression was not associated with p53, transforming growth factor-beta, Gli-1, YKL-40, or sonic hedgehog expression status. With regard to the expression site, the clinical characteristics did not differ between cases of cellular expression and those of stromal expression. However, ALDH1 expression in tumor cells was correlated with hormone receptor status, histological grade, molecular subtype, epidermal growth factor receptor expression status, and cytokeratin 5/6 expression status while stromal expression of ALDH1 was only correlated with hormone receptor status. Overall, these findings suggest that ALDH1 expression in tumor tissue is associated with a biologically aggressive phenotype. KEYWORDS: ALDH1, biologically aggressive, breast cancer.

Robotic thyroid surgery using bilateral axillo-breast approach: personal initial experience over two years.

AIM: Although endoscopic thyroid surgery is gaining wide acceptance, however, manual endoscopic operation also has shown several limitations. The advent of robotic surgical systems, such as the da Vinci surgical system (Intuitive Surgical, Mountain View, CA, USA), is expected to make it possible to overcome some limitations of manual endoscopic operation. Herein we report a single surgeon (H.Y.K.)'s initial two-year experience of new robotic thyroid operations using the bilateral axillo-breast approach (BABA), the approach which has definite advantages and recently has been widely used for the traditional endoscopic thyroid surgery. METHODS: Between July 2008 and July 2010, 93 patients underwent robotic thyroid surgery using the BABA, with the da Vinci-S surgical system, at the Korea University Anam Hospital, Seoul, Korea. The data on the patients' clinicopathological characteristics, operation types, operation times, surgical results, postoperative hospital stays and complications were collected in a prospective manner, and later evaluated. RESULTS: Seventy-two total thyroidectomies with or without central neck dissections mostly for the papillary carcinomas, twenty lobectomies with or without central neck dissections for the minute ­ smaller than 0.5 cm in their maximal diameter ­ papillary carcinomas, follicular neoplasms and benign tumors, and a bilateral subtotal lobectomy for the multinodular goiter were performed robotically. There was no conversion of robotic procedure to traditional endoscopic or open procedure. The mean total operation time was 288.5±48.0 minutes. The mean number of retrieved lymph nodes by the central neck dissection was 5.1±1.97 (range, 0-12). The mean hospital stay of the patients was 2.8±1.2 days. And the mean postoperative 3rd month serum thyroglobulin level in patients undergone total thyroidectomy was 0.3±0.14 ng/mL (range, 0.08-1.95). Three (3.2%) patients suffered from transient hoarseness postoperatively, but all of them recovered in three months. Transient hypocalcemias were observed in 17 out of 72 (23.6%) patients who had undergone total thyroidectomy, but none of them left permanent. No other complication, such as bleeding, infection, neither fluid collection, was observed. CONCLUSION: Our initial surgical results of robotic thyroid surgery using BABA demonstrate the feasibility and safety of the procedure in the treatment of benign tumors and early differentiated carcinomas.

NF-κB and STAT3 cooperatively induce IL6 in starved cancer cells.

A number of genes involved in tumorigenesis have been known to be controlled by signal transducer and activator of transcription 3 (STAT3) and NF-κB, either synergistically or individually. In starved cancer cells, we found that NF-κB was activated through endoplasmic reticulum stress signals, which depend on reactive oxygen species, cytosolic calcium and preserved translation of NF-κB p65 subunit, but independent of IκBα serine phosphorylation, thereby resulting in IL6 induction. STAT3 was required for proper induction of IL6 by NF-κB. They existed as identical nuclear complexes in proximal IL6 promoters, and STAT3 had critical roles in binding to IL6 promoters as well as nuclear retention of NF-κB. The conditioned media from starved cancer cells contained various secretory factors, such as IL6, IL9, VWF (von Willebrand factor), FREM1 (FRAS1 related extracellular matrix 1), SAA1 (serum amyloid A1), SDK1 (sidekick homolog 1) and ADAM12 (ADAM metallopeptidase domain 12), induced by NF-κB and STAT3 and promoted clonogenic capacities of cancer cells, and proliferation and migration of human umbilical vein endothelial cells. These results suggest novel survival strategies of cancer cells by which two oncogenic transcriptional factors, NF-κB and STAT3, are activated simultaneously by an intrinsic mechanism during stressful conditions of cancer cells, and they cooperatively induce various survival factors.

Correlation between the in vitro ATP-based chemosensitivity assay and HER2/neu expression in women with breast cancer.

Several in vitro chemosensitivity tests have been developed to predict the chemotherapeutic response of tumours prior to initiation of individualized treatment for breast cancer. This study investigated whether the in vitro chemosensitivity response of cell lines derived from breast cancer patients was affected by HER2/neu expression. We cultured breast cancer cell lines from 50 patients and the adenosine triphosphatebased chemotherapy response assay (ATPCRA) was performed with 5-fluorouracil, gemcitabine, docetaxel, doxorubicin, methotrexate, vinorelbine and paclitaxel. 5-fluorouracil combined a high median cell death rate (32.4%) with the narrowest range of cytotoxic effects (7.3-65.7%). In addition, gemcitabine showed significantly greater activity in HER2/neupositive patients. In contrast, docetaxel was significantly less effective in HER2/neu-positive patients. No significant correlation was found between the other agents and HER2/neu expression. The use of the ATP-CRA test for metastatic tissue from patients with recurrent disease might be a useful approach to determine the most effective chemotherapy regimen.