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WOS: 000385579200110, PubMed ID: 27703531, Prostate cancer (PCa) is the second most frequent type of cancer in men worldwide and the levels of differentiation growth factor midkine (MK) are increased in PCa. Cancer and/or the treatment process itself may lead to psychiatric disorders. Lithium chloride (LiCl) has anti-manic properties and has been used in cancer therapy; however, it has a queried safety profile. In addition, cancer stem cells are responsible for the heterogeneous phenotype of tumor cells; they are involved in progression, metastasis, recurrence and therapy resistance in various cancer types. The aims of the present study were to investigate the effect of different concentrations of LiCl on PCa stem cells (whether a shift from tumorigenic to non-tumorigenic cells occurs) and to determine if these results can be explained through changes in MK levels. Monolayer and spheroid cultures of human prostate stem cells and non-stem cells were incubated with low (1, 10 mu M) and high (100, 500 mu M) concentrations of LiCl for 72 h. Cell proliferation, apoptotic indices, MK levels and ultrastructure were evaluated. Cells stimulated with low concentrations showed high proliferation, low apoptotic indices, high MK levels and more healthy ultrastructure. Opposite results were obtained at high concentrations. Furthermore, stem cells were more sensitive to stimulation and more resistant to inhibition than non-stem cells. LiCl exhibited concentration-dependent effects on stem cell and non-stem cell groups. MK levels were not involved in the biphasic effect of LiCl; however, they were proportionally affected. To the best of our knowledge, the present study was the first to show the effect of LiCl on PCa stem cells through MK.

WOS: 000417293400016, Flavopiridol is a synthetically produced flavonoid that potently inhibits the proliferation of human tumor cell lines. Flavopiridol exerts strong antitumor activity via several mechanisms, including the induction of cell cycle arrest and apoptosis, and the modulation of transcriptional regulation. The aim of the present study was to determine the effect of flavopiridol on a subpopulation of cluster of differentiation (CD)44(+)/CD24(-) human breast cancer MCF7 stem cells. The CD44(+)/CD24(-) cells were isolated from the MCF7 cell line by fluorescence-activated cell sorting and treated with 100, 300, 500, 750 and 1,000 nM flavopiridol for 24, 48 and 72 h. Cell viability and proliferation assays were performed to determine the inhibitory effect of flavopiridol. Gene expression profiling was analyzed using Illumina Human HT-12 v4 Expression BeadChip microarray. According to the results, the half maximal inhibitory concentration (IC50) value of flavopiridol was 500 nM in monolayer cells. Flavopiridol induced growth inhibition and cytotoxicity in breast cancer stem cells (BCSCs) at the IC50 dose. The present study revealed several differentially regulated genes between flavopiridol-treated and untreated cells. The result of the pathway analysis revealed that flavopiridol serves an important role in translation, the ribosome biogenesis pathway, oxidative phosphorylation, the electron transport chain pathway, carbon metabolism and cell cycle. A notable result from the present study is that ribosome-associated gene expression is significantly affected by flavopiridol treatment. The data of the present study indicate that flavopiridol exhibits antitumor activity against CD44(+)/CD24(-) MCF7 BCSCs through different mechanisms, mainly by inhibiting translation and the ribosome biogenesis pathway, and could be an effective chemotherapeutic molecule to target and kill BCSCs.

WOS: 000344423800008, PubMed ID: 25216351, Flavopiridol is a flavone that inhibits several cyclin-dependent kinases and exhibits potent growth-inhibitory activity, apoptosis and G(1)-phase arrest in a number of human tumor cell lines. Flavopiridol is currently undergoing investigation in human clinical trials. The present study focused on the effect of flavopiridol in cell proliferation, cell cycle progression and apoptosis in prostate cancer stem cells (CSCs). Therefore, cluster of differentiation 133 (CD133)(+high)/CD44(+high) prostate CSCs were isolated from the DU145 human prostate cancer cell line. The cells were treated with flavopiridol in a dose- and time-dependent manner to determine the inhibitory effect. Cell viability and proliferation were analyzed and the efficiency of flavopiridol was assessed using the sphere-forming assay. Flavopiridol was applied to monolayer cultures of CD133(high)/CD44(high) human prostate CSCs at the following final concentrations: 100, 300, 500 and 1000 nM. The cultures were incubated for 24, 48 and 72 h. The half maximal inhibitory concentration (IC50) value of the drug was determined as 500 nM for monolayer cells. Dead cells were analyzed prior and subsequent to exposure to increasing flavopiridol doses. Annexin-V and immunofluorescence analyses were performed for the evaluation of apoptotic pathways. According to the results, flavopiridol treatment caused significant growth inhibition at 500 and 1000 nM when compared to the control at 24 h. G(0)/G(1), analysis showed a statistically significant difference between 100 and 500 nM (P

WOS: 000336555200071, Cancer stem cells (CSC) isolated from multiple tumor types differentiate in vivo and in vitro when cultured in serum; however, the factors responsible for their differentiation have not yet been identified. The first aim of the present study was to identify CD133(high)/CD44(high) DU145 prostate CSCs and compare their profiles with non-CSCs as bulk counterparts of the population. Subsequently, the two populations continued to be three-dimensional multicellular spheroids. Differentiation was then investigated with stem cell-related genomic characteristics. Polymerase chain reaction array analyses of cell cycle regulation, embryonic and mesenchymal cell lineage-related markers, and telomerase reverse transcriptase (TERT) and Notch signaling were performed. Immunohistochemistry of CD117, Notch1, Jagged1, Delta1, Sox2, c-Myc, Oct4, KLF4, CD90 and SSEA1 were determined in CSC and non-CSC monolayer and spheroid subcultures. Significant gene alterations were observed in the CD133(high)/CD44(high) population when cultured as a monolayer and continued as spheroid. In this group, marked gene upregulation was determined in collagen type 9 a1, Islet1 and cyclin D2. Jagged1, Delta-like 3 and Notch1 were respectively upregulated genes in the Notch signaling pathway. According to immunoreactivity, the staining density of Jagged1, Sox2, Oct4 and Klf-4 increased significantly in CSC spheroids. Isolated CSCs alter their cellular characterization over the course of time and exhibit a differentiation profile while maintaining their former surface antigens at a level of transcription or translation. The current study suggested that this differentiation process may be a mechanism responsible for the malignant process and tumor growth., Ege University Scientific Research Project FundEge University [Ege-BAP 2008 Tip-019], The authors would like to thank Professor Benjamin Bonavida for his editorial expertise; Assistant Professor Ogun Sercan for statistical analysis; Ummu Guven and Turker Cavusoglu for their support in Cell Culture Laboratory maintenance and inter-laboratory correlations; and Tayyibe Yeni and Merve Kursuner for flow cytometry and cell-sorting experiments in AREL. The current study was funded by a grant from the Ege University Scientific Research Project Fund (no. Ege-BAP 2008 Tip-019).

Rat C6 glioma is a chemo-resistant experimental brain tumor that is difficult to treat with various drug combinations. Previous studies suggested that imatinib mesylate (Gleevec) is effective in pre-clinical trials for glioblastoma. Also, chlorimipramine (Anafranil) is an anti-depressant drug in use in the clinic and shown to have anti-neoplastic activity. We hypothesized that treatment of resistant C6 glioma with combination of imatinib and chlorimipramine may potentiate cytotoxicity and reverse resistance. C6 glioma was examined both as monolayer and as spheroid cultures. Several experimental designs were examined all of which showed synergistic activity albeit at different time kinetics. Combination treatment resulted in inhibition of cell growth and enhanced cell death as determined by dye exclusion. Further, the combination treatment resulted in significant induction of apoptosis as determined by Annexin V-FITC and PI. Also, there was inhibition of DNA synthesis and cAMP. Altogether, these findings supported the anti-proliferative and cytotoxic effects of the combination treatment. Morphological studies were also performed using transmission and scanning electron microscopy. Significant synergistic apoptosis was detected by the combination treatment in both the monolayers and spheroid cultures. There was also a synergistic effect in autophagy by the combination. Several altered morphological features were noted by both the individual compound and enhanced by the combination treatment. The present findings support our hypothesis and demonstrate the potentiation of cytotoxicity by the combination of imatinib and chlorimipramine in C6 glioma. Further, the findings suggest the potential clinical application of the combination in the treatment of drug-resistant glioma.