Combining thioridazine and loratadine for the treatment of gastrointestinal tumor.

In 2015, the American Society of Clinical Oncology announced that strategies of using combination therapies have been indicated to be effective against many types of cancer. In the present study, thioridazine (THZ) was used in a combination therapy with loratadine (LOR) to target gastrointestinal tumor, with the aim of investigating whether combined therapy was superior to monotherapy in its antitumor effects. The antiproliferative effects on CT26.WT and MFC cells were analyzed using cell-counting kit-8 assay, and synergistic effect was assessed by combination index (Fig. 1). Annexin V and propidium iodide staining indicated the combination therapy was able to induce apoptosis and that this may be mediated via caspase-3, -9 and poly (ADP-ribose) polymerase (PARP) (Fig. 2). Antitumor activity was also evaluated in CT26.WT xenografts in BALB/c mice (Fig. 3). Furthermore, as expected, combination therapy was able to successfully inhibit the phosphoinositide 3-kinase/Akt/mammalian target of rapamycin signaling pathway (Fig. 4). These findings suggest that the combination therapy with THZ and LOR may provide a promising therapy for gastrointestinal cancer.

Ethacrynic acid improves the antitumor effects of irreversible epidermal growth factor receptor tyrosine kinase inhibitors in breast cancer.

Prolonged treatment of breast cancer with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) often results in acquired resistance and a narrow therapeutic index. One strategy to improve the therapeutic effects of EGFR TKIs is to combine them with drugs used for other clinical indications. Ethacrynic acid (EA) is an FDA approved drug that may have antitumor effects and may enhance the cytotoxicity of chemotherapeutic agents by binding to glutathione and inhibiting WNT signaling. While the α,ß-unsaturated-keto structure of EA is similar to that of irreversible TKIs, the mechanism of action of EA when combined with irreversible EGFR TKIs in breast cancer remains unknown. We therefore investigated the combination of irreversible EGFR TKIs and EA. We found that irreversible EGFR TKIs and EA synergistically inhibit breast cancer both in vitro and in vivo. The combination of EGFR TKIs and EA induces necrosis and cell cycle arrest and represses WNT/ß-catenin signaling as well as MAPK-ERK1/2 signaling. We conclude that EA synergistically enhances the antitumor effects of irreversible EGFR TKIs in breast cancer.

Evolution of hsp70 gene expression: a role for changes in AT-richness within promoters.

In disparate organisms adaptation to thermal stress has been linked to changes in the expression of genes encoding heat-shock proteins (Hsp). The underlying genetics, however, remain elusive. We show here that two AT-rich sequence elements in the promoter region of the hsp70 gene of the fly Liriomyza sativae that are absent in the congeneric species, Liriomyza huidobrensis, have marked cis-regulatory consequences. We studied the cis-regulatory consequences of these elements (called ATRS1 and ATRS2) by measuring the constitutive and heat-shock-induced luciferase luminescence that they drive in cells transfected with constructs carrying them modified, deleted, or intact, in the hsp70 promoter fused to the luciferase gene. The elements affected expression level markedly and in different ways: Deleting ATRS1 augmented both the constitutive and the heat-shock-induced luminescence, suggesting that this element represses transcription. Interestingly, replacing the element with random sequences of the same length and A+T content delivered the wild-type luminescence pattern, proving that the element's high A+T content is crucial for its effects. Deleting ATRS2 decreased luminescence dramatically and almost abolished heat-shock inducibility and so did replacing the element with random sequences matching the element's length and A+T content, suggesting that ATRS2's effects on transcription and heat-shock inducibility involve a common mechanism requiring at least in part the element's specific primary structure. Finally, constitutive and heat-shock luminescence were reduced strongly when two putative binding sites for the Zeste transcription factor identified within ATRS2 were altered through site-directed mutagenesis, and the heat-shock-induced luminescence increased when Zeste was over-expressed, indicating that Zeste participates in the effects mapped to ATRS2 at least in part. AT-rich sequences are common in promoters and our results suggest that they should play important roles in regulatory evolution since they can affect expression markedly and constrain promoter DNA in at least two different ways.

Daidzein enhances osteoblast growth that may be mediated by increased bone morphogenetic protein (BMP) production.

Daidzein, a natural isoflavonoid found in Leguminosae, has received increasing attention because of its possible role in the prevention of osteoporosis. In the present investigation, primary osteoblastic cells isolated from newborn Wistar rats were used to investigate the effect of this isoflavonoid on osteoblasts. Daidzein (2-50 microM) increased the viability (P<0.05) of osteoblasts by about 1.4-fold. In addition, daidzein (2-100 microM) increased the alkaline phosphatase activity and osteocalcin synthesis (P<0.05) of osteoblasts by about 1.4- and 2.0-fold, respectively. Alkaline phosphatase and osteocalcin are phenotypic markers for early-stage differentiated osteoblasts and terminally differentiated osteoblasts, respectively. Our results indicated that daidzein stimulated osteoblast differentiation at various stages (from osteoprogenitors to terminally differentiated osteoblasts). We also investigated the effect of daidzein on bone morphogenetic protein (BMP) production in osteoblasts that display the mature osteoblast phenotype. The results indicated that BMP2 synthesis was elevated significantly in response to daidzein (the mRNA increased 5.0-fold, and the protein increased 7.0-fold), suggesting that some of the effects of daidzein on the cell may be mediated by the increased production of BMPs by the osteoblasts. In conclusion, daidzein has a direct stimulatory effect on bone formation in cultured osteoblastic cells in vitro, which may be mediated by increased production of BMPs in osteoblasts.