The kinesin Eg5 inhibitor K858 induces apoptosis but also survivin-related chemoresistance in breast cancer cells.

Inhibitors of kinesin spindle protein Eg5 are characterized by pronounced antitumor activity. Our group has recently synthesized and screened a library of 1,3,4-thiadiazoline analogues with the pharmacophoric structure of K858, an Eg5 inhibitor. We herein report the effects of K858 on four different breast cancer cell lines: MCF7 (luminal A), BT474 (luminal B), SKBR3 (HER2 like) and MDA-MB231 (basal like). We demonstrated that K858 displayed anti-proliferative activity on every analyzed breast cancer cell line by inducing apoptosis. However, at the same time, we showed that K858 up-regulated survivin, an anti-apoptotic molecule. We then performed a negative regulation of survivin expression, with the utilization of wortmannin, an AKT inhibitor, and obtained a significant increase of K858-dependent apoptosis. These data demonstrate that K858 is a potent inhibitor of replication and induces apoptosis in breast tumor cells, independently from the tumor phenotype. This anti-proliferative response of tumor cells to K858 can be limited by the contemporaneous over-expression of survivin; consequently, the reduction of survivin levels, obtained with AKT inhibitors, can sensitize tumor cells to K858-induced apoptosis.

Breast cancer cells respond differently to docetaxel depending on their phenotype and on survivin upregulation.

Breast cancer is characterized by molecular heterogeneity, and four major breast cancer subtypes have been identified, each characterized by significant differences in survival, prognosis, and response to therapy. We have studied the effects of docetaxel treatment on apoptosis and survivin expression in four breast cancer cell lines: MCF7 (luminal A: estrogen receptor-positive and progesterone receptor-positive, ErbB2-negative), BT474 (luminal B: estrogen receptor/progesterone receptor/ErbB2-positive), SKBR3 (HER2-like: estrogen receptor/progesterone receptor-negative, ErbB2-positive), and MDA-MB231 (basal-like: estrogen receptor/progesterone receptor/ErbB2-negative). We demonstrated that docetaxel-induced apoptosis and survivin upregulation (MCF7 p = 0.002, BT474 p = 0.001, SKBR3 p = 0.001) in luminal A/B and HER2-like cells, while it induced mainly necrosis and a lower rate of survivin upregulation (MDA-MB231 p = 0.035) in basal-like cells. Wortmannin, a p-Akt inhibitor, was able to revert surviving upregulation and, at the same time, induced an increase of docetaxel-dependent apoptosis, suggesting that reduced levels of survivin can sensitize tumor cells to apoptosis. These data show that the analyzed breast cancer cell lines respond differently to docetaxel, depending on their receptor expression profile and molecular phenotype. Yet, these data confirm that one of the pathways involved in taxane-related chemoresistance is the upregulation of survivin. Further studies on the molecular mechanisms of chemoresistance and on the different modalities of apoptosis induced by chemotherapeutic agents are requested to better understand how cancer cells evade cell death, in order to design new kind of anticancer agents and survivin could represent a future target for this kind of research.

Effect of surgery on pancreatic tumor-dependent lymphocyte asset: modulation of natural killer cell frequency and cytotoxic function.

OBJECTIVES: Tumor burden and invasiveness establish a microenvironment that surgery could alter. This study shows a comprehensive analysis of size, dynamics, and function of peripheral lymphocyte subsets in pancreatic cancer patients before and at different times after duodenopancreatectomy. METHODS: Lymphocyte frequency and natural cytotoxicity were evaluated by flow cytometry and in vitro assay on peripheral blood from initial and advanced-stage pancreatic cancer patients before (BS), at day 7 (PS7), and at day 30 (PS30) after surgery. RESULTS: An increase in natural killer (NK) cells and the diminution of B-cells occurred at PS30, whereas cytotoxicity decreased at PS7. The positive correlation between NK frequency and cytotoxicity at BS and PS7 revealed an altered NK behavior. The elevation of NK cell frequency at PS30, an initial defect in CD56bright NK, and the aberrant correlation between NK frequency and cytotoxicity remained significant in advanced-stage patients, whereas the diminution of NK cytotoxicity only affected initial stage patients. CONCLUSIONS: The NK cell functional ability is altered in presurgery patients; duodenopancreatectomy is associated with short-term impairment of NK function and with a long-term NK cell augmentation and reversion of the aberrant NK behavior, which may impact on immunosurveillance against residual cancer.

Serum levels of functional T-regs in vitiligo: our experience and mini-review of the literature.

Vitiligo is an acquired depigmentary skin disorder due to the loss of cutaneous melanocytes or alteration in melanocyte function, affecting over 0.5% of the world population. The exact cause of melanocyte loss in non-segmental vitiligo is still debatable, but many observations have pointed to the main role of cellular immunity. Earlier evidence has shown that depigmenting vitiligo skin is accompanied by CD8+ T cytotoxic lymphocytes infiltrates at the dermal-epidermal junction. Dysregulation of Tregs may be one of the factors that can break tolerance to melanocyte self-antigens and contribute to the pathogenesis of vitiligo. The objectives of the present study were to provide evidence of the presence of a functional defect and decrease of peripheral regulatory T cells in patients affected by vitiligo, supporting the hypothesis of their involvement in the pathogenesis of the disease, opening new possibilities to advance therapeutic approaches.

CD4+ CD25+ T-regulatory cells in psoriasis. Correlation between their numbers and biologics-induced clinical improvement.

BACKGROUND: Regulatory T-cells (T-reg) play a central role in the immunopathogenesis of psoriasis. T-reg cells are both functionally and numerically impaired in psoriasis and they are up-regulated by drug therapy. OBJECTIVE: To analyse the circulating CD4+CD25 bright FOXP3+ subset in 14 patients with vulgaris/arthropathic psoriasis treated with biological drugs and to investigate their relationship with the clinical response. METHODS: The CD4+ CD25 bright FOXP3+ expression was determined in peripheral blood by flow cytometry at baseline and during treatment. RESULTS: A response was obtained in 10/14 patients with increased CD4+ CD25 bright FOXP3+ (T-reg) in peripheral blood after the first month and then 4 months after therapy with biological drugs. This increase is associated with the achievement of a clinical response and with a reduction in the Psoriasis Activity and Severity Index (PASI) score. 2/14 patients showed a decrease in T-reg after drug therapy and this decrease correlated with a worsening of the clinical skin. CONCLUSION: Biological drugs induce circulating T-reg up-regulation in psoriatic patients; such an increase is an early predictive marker of clinical response.