In this study the antiproliferative effects of Paclitaxel (PAC), Epirubicin (EPI) and Tamoxifen (TAM) on growth kinetics of Ehrlich Ascites Tumor (EAT) cells were examined in culture. An estrogen-receptor-positive ER (+) hyperdiploid EAT cell line growing in vitro was also analysed in the present study. IC50 doses of PAC, EPI and TAM (12 microg/ml, 12 microg/ml and 2 microg/ml, respectively) were used. Cells were treated with the above doses for 0, 4, 8, 16, 24 and 32 hrs. At the end of these periods, living cell numbers were determined by collecting EAT cells in every group for growth study rate and for MTT assay. Therefore, the mitotic index was determined in the same experimental groups. The proliferation of EAT cells, inhibited by PAC, EPI and TAM concentrations was compared to control with increasing treatment time (4-32 hrs). Treatment of PAC, EPI and TAM alone for 24 hrs decreased the proliferation rate of EAT cells by 50% with respect to control. The inhibition of proliferation rate was higher in double drug treatment than that in single drug treatment with increased treatment time. In the treatment of three drugs applied for 32 hrs, this effect reached a maximum and proliferation rate decreased by 12% as compared to the (100%) control. In our studies, when the mitotic index parameter data were evaluated to determine which phase of the cell cycle was affected by PAC to cause the repression of cell reproduction, it was found that PAC exerted of its cytotoxic effect by causing cell accumulation at mitosis. The accumulation of the cells resulted in an increase in mitotic index values, which was an expected consequence of PAC treatment. It was observed that depending on the drug treatments, inhibition of proliferation rate and mitotic index in EAT cells were increased with respect to control, being with statistically significant occurrence (p < 0.01 - p < 0.001). As a result, concomitant treatment combined with hormonal therapy has given improved results compared with single treatment and PAC + EPI + TAM treatments had a maximum synergistic effect for 32 hrs (p < 0.001).

We aim to determine the regulation of apoptosis by paclitaxel-induced and understand cancer dynamics to treatment targets for HeLa cells by identifying decrease/increase genes expression on HeLa cells. In this study, the anti-tumor effects of Paclitaxel (PAC) on HeLa cells have been studied in order to determine the cellular and molecular mechanisms of these effects. PAC has been applied to HeLa cells in 6 different doses (3, 7.5, 15, 30, 60, 120 nM) for 48 hours and the IC50 dose MTT method, has been determined with apoptic index (AI) DAPI. Morphological aspects have been demonstrated using light, phase contrast and fluorescent microscopes, additionally activation of Caspase 3,7 and 10 have been shown using florescent spectroscopy. RT-PCR and qRT-PCR have been used to evaluate pro/anti-apoptotic gene expression. According to the parameters being evaluated; PAC has reduced cell multiplication based on dosage and time (p<0.01). 15 nM has been determined as the IC50 value. AI value has been determined as 42%. In the molecular level analyses in addition to the increase in Caspase3,7,10 activation, RT-PCR results show that bax, bak, bcl-x, bik, mcl-1 genes are expressed in the control group as well as the experimental 15 nM group; whereas bak, bcl-x ve bik genes have a decrease in expression compared to the control group. qRT-PCR results show that Apaf1, Bad, Bax, Bcl2L11, Caspase1, Caspase10, Caspase4, Caspase7, Dffa, Fas, Htra2, Lrdd, NFKB1, NFKB2, PMAIP1, RELA, RELB, TNFRSF10A, TNFRSF10C, TNFRSF10D, TNFRSF1A, TNFRSF21, TNFRSF25 gene expressions have increased significantly. On the other hand, BAG1, BBC3, Bcl2L1, Bcl2L10, Bid, Caspase2, Caspase6, Caspase8, Caspase9, FADD, FAM96A, FasLG, HRK, SOCS3, TNF, TNFSF10, TRAF5, TRAF6 mRNA levels are significantly decreased.

Nowadays increasing effectiveness in cancer therapy and investigation of formation of new strategies that enhance antiproliferative activity against target organs has become a subject of interest. Although the molecular mechanisms of apoptosis can not be fully explained, it is known that cell suicide program existing in their memory genetically is activated by pathophysiological conditions and events such as oxidative stress. Low pressure (hypobaric) conditions that create hypoxia promote apoptosis by inhibiting cell cycling. In this study, determination of the effects of fractional hypobaric applications at different times on HeLa cells at cellular and molecular levels were targeted. Experiments were carried out under hypobaric conditions (35.2 kPa) in a specially designed hypobaric cabin including 2% O-2 and 98% N. Application of fractional hypobaric conditions was repeated two times for 3 hours with an interval of 24 hours. At the end of the implementation period cells were allowed to incubate for 24 hours for activation of repair mechanisms. Cell kinetic parameters such as growth rate (MTT) and apoptotic index were used in determination of the effect of hypobaric conditions on HeLa cells. Also in our study expression levels of the Bcl-2 gene family that have regulatory roles in apoptosis were determined by the RT-PCR technique to evaluate molecular mechanisms. The results showed that antiproliferative effect of hypobaric conditions on HeLa cells started three hours from the time of application and increased depending on the period of exposure. While there was a significant decrease in growth rate values, there was a significant increase in apoptotic index values (p<0.01). Also molecular studies showed that hypobaric conditions caused a significant increase in expression level of proapoptotic gene Bax and significant decrease in antiapoptotic Bfl-1. Consequently fractional application of hypobaric conditions on HeLa cell cultures increased both antiproliferative and apoptotic effects and these effects were triggered by the Bax gene.

HSP70 is a molecular chaperone that plays a critical role in normal physiology of the cell and highly activated under pathological conditions such as cancer. It has been well established that HSP70 is implicated in breast cancer development and progression. Highly activated HSP70 has been linked to processes, such as cell proliferation, metastasis, drug resistance, and driving anti-apoptotic pathways. In the Luminal A subtype, HSP70 stabilizes the ESR1 (estrogen receptor 1) and PIK3CA (phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha) pathways, supporting cell survival, while in the Luminal B subtype, its interaction with Cyclin D1 and TP53 contributes to treatment resistance. In the HER2 (+) subtype, HSP70 triggers aggressive tumor growth by increasing human epidermal growth factor receptor 2 (HER2) signaling via stabilizing the protein. In triple-negative breast cancer (TNBC), it supports stem cell-like properties by interacting with pathways, such as neurogenic locus notch homolog protein 1 (NOTCH1) and nuclear factor-kappa B (NF-κB) and suppressing anti-apoptotic pathways. The effect of HSP70 on cancer stem cells (CSCs) plays an important role in limiting therapeutic response as well as tumor initiating potential and metastasis. In turn, it inhibits apoptosis, preventing cell death through B-cell lymphoma 2 (BCL-2) stabilization and suppression of caspase activity. This review aims to provide an integrative view of breast cancer biology by addressing the functions of HSP70 in cancer subtypes, interactions with cancer stem cells and apoptosis.

The objectives of this study are to identify changes in gene expression, which involved in apoptosis pathways induced by gamma radiation, Cervical cancer cells were exposed to various doses of a single fraction of gamma radiation. After incubation for different periods, the proliferation of C-4 I and HeLa cells were investigated by MTT assay, wile morphological features were assessed by fluorescent microscopy to measure the Apoptotic Index (AI). In addition, gene expression was evaluated using micro-array molecular processes, and signalling pathway analysis were performed. Gamma irradiation inhibits proliferation of HeLa and C-4 I cells in a time- and dose- dependent manner. From our results a significant difference was observed between HeLa and C-4 I cell lines (p < 0.01), whereas, HeLa cells seemed to be radio resistant, while C-4 I cells radio-sensitive. IC50 and AI dose for C-4 I and HeLa cells were 16 Gy and 32 Gy respectively. Microarray results monitored the expression of some factors that are known apoptosis activators were up regulated by gamma radiation treatment, whereas some anti-apoptosis members were down regulated. Pathway analysis identified that significant pathways related to apoptosis, WNT, cell cycle and P53 were significantly reinforced. These results give evidence that ionized radiation directly induces anti proliferative effects by converting the expression of genes related to apoptosis and cell proliferation pathways in HeLa and C-4 I cervical cancer cells.