Effects of Salinomycin and Everolimus on Breast Cancer Stem Cells in Hypoxia

Cancer stem cells (CSCs) are a collection of small numbers of cells that have the potential to induce all cell types within the tumor mass and have self-renewal capacity. Today, the reasons for the failure of conventional cancer therapies lie in the fact that they are unable to target cancer stem cells. Targeting the cancer stem cell is thought to provide a very important and revolutionary advance in cancer cell targeting and therapy Tumor hypoxia is a characteristic of solid tumors and has been associated with poor prognosis and resistance to radiotherapy and chemotherapy. HIF-1 (Hypoxia Inducible Factor-1) is the major transcription factor activated in hypoxic conditions and allows transcriptional activation of various genes that are effective for the adaptation of the cell to the hypoxic condition. Experimental studies have provided evidence that also hypoxia and HIF-1alpha%253B promote the cancer stem cell phenotype and targeting of HIF-1alpha%253B may reduce or eliminate cancer stem cells. Breast cancer is the most common form of cancer in women worldwide and affects 10%25 of the world%252339%253Bs female population. 25%25 to 30%25 of patients with invasive breast cancer still die from this disease. The recurrence frequency of the disease varies between 60%25 and 80%25 within the first 3 years after treatment. In order to target breast cancer stem cells more effectively, in this study we aimed to reveal whether the hypoxic conditions in the tumor, which act as the stem cell production area, at the same time creates resistance to therapy. Thus, we evaluated effect of CSCs targeting agent Salinomycin alone or in combination with Everolimus which is an m-TOR and HIF-1alpha%253B inhibitor on parental MCF-7 and MDA-231 breast cancer cells and their isolated CSCs in hypoxic conditions. Here it is presented that starting with 2 mM, increased concentrations of salinomycin significantly inhibits proliferation and induce apoptosis in hypoxia, in both parental MCF-7 and MDA-231 breast cancer cells and in their isolated CSCs. The most effective concentration of salinomycin was 10 mM and induced around 35%25 and 45%25 of apoptosis in both parental MCF-7 and MDA-231 and their isolated CSCs, respectively. Whereas everolimus alone was not as effective as salinomycin, as 25 mM everolimus induced 30%25 and 15%25 of growth inhibition or apoptosis in both parental and CSCs of MCF-7 and MDA-231 cellsin hypoxia, respectively. When lower concentrations of salinomycin (2mM) and everolimus (5mM) was used in combination they show synergistic effect and able to inhibit proliferation at least 35%25 and 45%25 in both parental and CSCs of MCF-7 and MDA-231 cells in hypoxia, respectively. Similar results were also obtained for induction of apoptosis in response to salinomycin %2B everolimus treatment in hypoxia in both parental and CSCs of MCF-7 and MDA-231 cells. Hence using lower concentrations of salinomycin and everolimus together may provide an effective targeting strategy for hypoxic CSCs and may contribute to the development of novel strategies for therapeutic intervention in breast cancer

Investigation of the Anti-Cancer Effects of B-asaron and Etoposide in MCF-7 Breast Cancer Cells

Currently, the options available for the treatment of various cancers including breast cancer, are associated with several limitations such as severe toxicity, drug resistance, poor prognosis, and high risk of recurrence. Therefore, there appears to be an increasing interest and necessity in investigating various phytochemicals from natural sources for a superior and safer alternative treatment strategy. The bioactive phytochemical alpha (alpha%253B) and beta (beta%253B)-asarone from Acorus calamus is a traditional medicine system that has been shown to have anti-tumor and chemo-inhibitory activities in numerous preclinical studies both in vitro and in vivo. Various experimental studies with human malignant cell lines and animal models have also confirmed the anti-tumor and anti-cancer activities of beta%253B-asarone. In this study, we aimed to investigate the anti-cancer effects of beta%253B-asarone alone or together with etoposide buy measuring cellular responses such as cell viablity, cell cycle arrest and apoptosis using breast cancer cell line MCF-7 cells. In order to get insight in to the mechanism, we also tested the expression of of NF-kappa%253BB %252F p65 activity and the expression of Bcl-2 family member pro-apoptotic Bax protein together with p53 and p21 activities in response to beta%253B-asarone alone or together with etoposide treatment. As a result, it was concluded that the use of beta%253B-asarone alone in breast cancer cells is effective in reducing cell viability, but when used together with Etoposide, it does not cause a synergistic effect. Here we suggest that that in particular activation of NF-kB%252Fp65 may be lead resistance to etoposide treatment

Therapy Induced Senescence Promote Expression of Death Receptors in Breast Cancer Cells

Chemotherapeutic agents that cause DNA damage also induce cellular senescence known as therapy-induced senescence (TIS). Cells undergoing senescence may exert detrimental effects by promoting tumor progression in healthy cells or supporting metastases in cancer cells due to senesence-associated secretory phenotype (SASP), involving secretion of chemokines, cytokines, metalloproteinases, and growth factors. Death receptors belong to the tumor necrosis factor receptor superfamily and implicated in induction of apoptosis via activation of extrinsic pathway. The most recognized death receptors are FAS (CD95), TNFR1 and TRAIL-R1 %252F 2 (DR4-DR5) etc. and capable of directly inducing apoptosis in the cell. In this study we aim to investigate the expression of cell death receptors in response to TIS of breast cancer cells for their potential use in elimination of senescent cells. Doxorubicin and etoposide were used to induce senescence selectively in MCF7 breast cancer cell line. Senescence induction was confirmed by beta%253B-galactosidase staining and cell cycle analysis. Activations of p53, p21, and gamma%253B-H2AX and expression levels of cell death receptors (FAS (CD95), TNFR1-2 and DR5 were tested by western blot analysis. Apoptosis was measured by Annexin V%252F7AAD analysis. Here, we show that chemotherapy agents etoposide and doxorubicin induced senescence by arresting MCF-12A and MCF-7 cells in G1 and G2%252FM phases of cell cycle., respectively. In addition, Induction of senescence is confirmed by SA-beta%253B-gal staining and by activation of g-H2AX, p53 and p21 proteins. Neither etoposide nor doxorubicin induced significant apoptosis in MCF12A or MCF-7 cells. Importantly, TIS increased the protein levels of TNFR1, TNFR2 and DR5 receptors selectively in MCF-7 cells but not in MCF-12A cells. These data suggest that chemotherapy agents induce senescence increased the expression of death receptors in breast cancer cell line MCF-7 thus provide a basis for further investigation of death receptor mediated targeting of senescent cells as potential therapeutic strategy

Characteristics of food allergy in children: National multicenter study

Conference: Congress of the European-Academy-of-Allergy-and-Clinical-Immunology (EAACI) Location: Lisbon, PORTUGAL Date: JUN 01-05, 2019Background : Food allergies impose a significant burden on the life of the child and the family. In this study, to determine the demographic characteristics of food allergies, we investigated the characteristics of patients with food allergies in different regions of Pediatric Allergy- Immunology departments in Turkey. Method : Turkey ' s National Study of Allergy and Clinical Immunology Society has conducted a Study Group on Food Allergies. 25 centers participated in this multicenter, cross- sectional and descriptive study.European Academy of Allergy and Clinical Immunolog

DNA Damage Response and Autophagy%253A An Exclusive Meeting in Cancer

Healthy cells maintain genome integrity by activating a conserved DNA damage response (DDR) pathway that halts the progression of the cell cycle and activates DNA repair. Molecular disorders preventing DDR functioning properly often predispose to cancer. Therefore DDR acts as a tumor suppressor barrier. DDR often leads to not only cell cycle arrest and DNA repair, but also induces cellular senescence and apoptosis. Ultimately, autophagy as a self-degradation and recycling program of cellular components can be induced by DDR. In healthy cells and the initial stage of cancer, autophagy appears to have a tumor suppressor function by eliminating damaged organelles, and protein aggregates to promote genomic instability. However, in advanced tumors, autophagy s activated, particularly as a result of hypoxia and metabolic stress, to promote tumor survival under these conditions. Autophagy can also be induced by DNA damaging chemotherapy agents in tumor cells, which mostly results in resistance to conventional cancer therapies. In addition, activation of certain oncogenes in advanced tumors may promote autophagy activation and guarantee the persistence of tumors. Thus, currently development of inhibitors targeting autophagy with potential clinical use is increasing rapidly. In this review, the DDR and autophagy signaling mechanisms, as well as the interconnecting pathways of both are highlighted. Moreover, the biological consequences of the companion of these two important cellular responses in cancer are discussed

'DNA Hasarı Yanıtı'nın İnce Ayarında PPM1D/Wip1 Fosfataz'ın Rolü

Sağlıklı hücreler genom bütünlüğünü, hücre döngüsündeki ilerleyişi erteleyen%252Fdurduran ve DNA tamirini devreye sokan korunmuş bir DNA hasarı yanıtı yolağını aktive ederek sürdürürler. Bu sinyal yolağının düzgün olarak çalışmasını engelleyen moleküler bozukluklar genellikle kansere yatkınlık kazandırırlar. DNA hasarı yanıtı (DDR), hücreleri genomik kararsızlıktan korur ve kanser gelişimini önler. DNA hasarının moduna ve seviyesine bağlı olarak, DDR sinyal ağı hücre döngüsünün geçici durdurulmasını (kontrol noktası), kalıcı büyümenin durdurulmasını (yaşlanma, senesens) veya programlanmış hücre ölümünü (apoptozis) teşvik eder. DDR%2526%252339%253Bye katılan proteinleri kodlayan genler tipik olarak tümör baskılayıcılardır ve yaygın olarak kanserde mutasyona uğrarlar. DDR yolağı temel olarak proteinlerin fosforilasyon ve defosforilasyonlarını kapsayan bir mekanizma ile düzenlenir. Yabanıl tip p53 ile indüklenen fosfataz veya (Wild-type p53-inducible phosphatase (Wip1)), veya protein fosfataz tip 2C delta (protein phosphatase type 2C delta (PPM1D)) olarak da bilinen Wip1, DDR ın merkezinde yer alan ve önemli tümör baskılayıcıları hedef alan bir onko-proteindir. Bu derleme de, DDRnin ince ayarında Wip1 aktivitesinin rolü ve bir onkogen olarak apoptozis ve senesens gibi hücresel stres yanıtları üzerine etkileri tartışılmıştır

Meme Kanser Kök Hücre Fenotipi ve TümörHipoksisi ile İlişkisi

Kanser kök hücreleri, bir tümör içindeki nadir ölümsüz hücrelerdir ve bölünerek kendiliğinden yenilenebilir ve tümörü oluşturan birçok hücre türüne köken oluşturabilir. Bu hücreler çeşitli insan tümörlerinde bulunmaktadır ve kanser tedavisi için hedefler olarak ilgi çekmektedirler. Günümüzde konvansiyonel kanser terapilerinin başarısız olma nedenlerinin temelinde kemoterapi ya da radyoterapiye karşı aşırı direnç gösteren ve daha yavaş proliferasyon kapasitesine sahip kanser kök hücrelerini hedefleyememeleri yatmaktadır. Bunun sonucunda da dormant, yani uyuyan kanser kök hücreleri yeniden proliferatif faza girmekte ve bu da sıklıkla relapsla sonuçlanmaktadır. Kanser kök hücrenin hedeflenmesinin kanserin hedeflenmesinde ve tedavisinde çok önemli ve devrimsel nitelikte ilerlemeler sağlayacağı düşünülmektedir. Kanser kök hücrelerin regülasyonunda, Wnt%252F%2526beta%253B-catenin, Notch ve Hedgehog gibi epitelyal mezenkimal dönüşüm sinyal yollarının aktivasyonunun etkili olduğu bilinmektedir. Deneysel çalışmalar, hipoksinin ve Hypoxia Inducible Factor-1%2526alpha%253Bnın (HIF-1%2526alpha%253B) kanser kök hücre fenotipini teşvik ettiği ve HIF-1%2526alpha%253Bnın hedeflenmesinin de kanser kök hücreleri azalttığı veya elemine ettiği konusunda kanıtlar sağlamıştır. Meme kanseri dünya genelinde kadınlarda en yaygın diagnozu olan kanser formudur ve dünya kadın popülasyonunun %2510unu etkilemektedir. İnvaziv meme kanserine sahip olan hastaların %2525-%2530 %2526lsquo%253Bu halen bu hastalık sebebiyle ölmektedirler. Tedaviden sonraki ilk 3 yıl içerisinde hastalığın rekürans sıklığı ise %2560-%2580 arasında değişmektedir. Meme kanser kök hücrelerinin daha etkin bir şekilde hedeflenebilmesi için, tümör içerisinde özellikle kök hücre üretim alanı gibi davranan hipoksik alanlar, aynı zamanda bu hücreleri terapiye dirençli hale getirebilir ve hipoksi indüklü faktörlerin bu dirençte rollerinin ortaya çıkarılması önemlidir. Bu bilgiler ışığında, gelecekte yeni ve etkili tedavi stratejileri geliştirmek için, ilaç direncinin tersine çevrilebilir olup olmadığının ve HIF-1%2526alpha%253B inhibitöleri ve kök hücre hedefleme ajanlarının kombinasyon tedavileri ile meme kanser kök hücrelerin elimine edilip edilemeyeceğinin araştırılması özellikle önem kazanmaktadır

Effects of bone marrow-derived mesenchymal stem cells on doxorubicin-induced liver injury in rats

Doxorubicin (DOX) is a potent chemotherapeutic agent and has toxic effects on various organs, including the liver. In the current study, we aimed to investigate the effects of bone-marrow-derived mesenchymal stem cell (BM-MSC) administration on DOX-induced hepatotoxicity in rats. 24 Wistar-albino rats were divided into three groups: Control, DOX, and DOX+MSC. DOX (20 mg/kg) was administered to the DOX group. In the DOX + MSC group, BM-MSCs (2 x 10(6)) were given through the tail vein following DOX administration. DOX administration led to significant structural liver injury. Besides this, oxidative balance in the liver was impaired following DOX administration. DOX administration also led to an increase in apoptotic cell death in the liver. Structural and oxidative changes were significantly alleviated with the administration of BM-MSCs. Furthermore, BM-MSC administration suppressed excessive apoptotic cell death. Our findings revealed that BM-MSC administration may alleviate DOX-induced liver injury via improving the oxidative status and limiting apoptotic cell death in the liver tissue