Increased effects of MPDAX, a novel xanthine derivative, on antitumor activity of doxorubicin

Rutin and orlistat produce antitumor effects via antioxidant and apoptotic actions

Cancer is a broad term used to describe a large number of diseases characterized by uncontrolled cell proliferation that leads to tumor production. Cancer is associated with mutations in genes controlling proliferation and apoptosis, oxidative stress, fatty acid synthase (FAS) expression, and other mechanisms. Currently, most antineoplastic drugs have severe adverse effects and new effective and safe drugs are needed. This study aims to investigate the possible anticancer activity of rutin and orlistat which are both safely used clinically in humans against two breast cancer models (in vivo EAC and in vitro MCF7) and the pancreatic cancer cell line (PANC-1). Our results have shown that both rutin and orlistat exerted an in vivo anticancer activity as evidenced by the decrease in tumor volume, CEA level, cholesterol content, FAS, and the exerted antioxidant action (reduced MDA level and increased GSH content) and through histopathological examination. In addition, both were cytotoxic to MCF-7 and Panc-1 cell lines by promoting apoptosis. In conclusion, the anticancer activity of rutin and orlistat makes them promising candidates for cancer treatment alone or in combination with other anticancer drugs specially that they are used clinically with an acceptable safety profile.

Inhibitory Effects of New Mercapto Xanthine Derivatives in Human mcf7 and k562 Cancer Cell Lines

A series of new 2‐methyl‐2‐[(1,3‐Diethyl‐2,6‐dioxo‐2,3,6,7‐tetrahydro‐1H‐purin‐8‐yl)thio]‐N‐ substituted arylacetamides were synthesized. The antitumor activity of these purine based compounds were evaluated on breast cancer (MCF7) and leukemic cancer (K562) cell lines via cell viability assay utilizing the tetrazolium dye 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT). These results were substantiated using computer docking experiments (LigandFit docking engine and PMF scoring function) which predict that the antitumor activity of these new compounds may be attributable to their abilities to effectively bind and block oncogenic tyrosine kinases, particularly bcr/abl.

PPARγ-dependent anti-tumor and immunomodulatory actions of pioglitazone

Peroxisome proliferator-activated receptor-γ (PPARγ) has been reported to play important roles in carcinogenesis. The current study was carried out to assess the possible anti-tumor effects of pioglitazone (PIO), a PPARγ agonist, in a mouse mammary carcinoma model, i.e. a solid Ehrlich carcinoma (SEC). Effects of PIO on tumor-induced immune dysfunction, and the possibility that PIO may modulate the anti-tumor and immunomodulatory effects of doxorubicin (DOX) were also studied. The effects in tumor-bearing hosts of several doses of PIO (100 mg/kg, per os), with and without the added presence of DOX (2 mg/kg, IP), was investigated in vivo; end-points evaluated included assessment of tumor volume, splenic lymphocyte profiles/functionality, tumor necrosis factor (TNF)-α content, as well as apoptosis and expression of nuclear factor-κB (NF-κB) among the tumor cells. The data indicate that PIO induced significant anti-tumor activity against the SEC. PIO treatments also significantly mitigated both tumor- and doxorubicin-induced declines in immune parameters assessed here. Moreover, PIO led to decreased NF-κB nuclear expression, and, in doing so, appeared to chemo-sensitize these tumor cells to DOX-induced apoptosis. All pioglitazone-studied effects were antagonized by GW9662, a selective PPARγ antagonist.

Role of cysteinyl leukotriene receptor-1 antagonists in treatment of experimentally induced mammary tumor

It has been reported that a leukotriene (LT)-D4 receptor (i.e. cysteinyl LT1 receptor; CysLT1R) has an important role in carcinogenesis. The current study was carried out to assess the possible antitumor effects of montelukast (MON), a CysLT1R antagonist, in a mouse mammary carcinoma model, that is, a solid Ehrlich carcinoma (SEC). Effects of MON on tumor-induced immune dysfunction and the possibility that MON may modulate the antitumor and immunomodulatory effects of doxorubicin (DOX) were also studied. The effects in tumor-bearing hosts of several dosings with MON (10 mg/kg, per os), with and without the added presence of DOX (2 mg/kg, intraperitoneal), were investigated in vivo; end points evaluated included assessment of tumor volume, splenic lymphocyte profiles/functionality, tumor necrosis factor-α content, as well as apoptosis and expression of nuclear factor-κB (NF-κB) among the tumor cells. The data indicate that MON induced significant antitumor activity against the SEC. MON treatments also significantly mitigated both tumor- and DOX-induced declines in immune parameters assessed here. Moreover, MON led to decreased NF-κB nuclear expression and, in doing so, appeared to chemosensitize these tumor cells to DOX-induced apoptosis.

Mouse Equilibrative Nucleoside Transporter 2 (mENT2) Transports Nucleosides and Purine Nucleobases Differing from Human and Rat ENT2

Several mammalian nucleoside transporters have been identified at the molecular level. Human and rat equilibrative nucleoside transporter 2 (hENT2 and rENT2, respectively) was previously reported to have the dual ability of transporting both nucleosides and nucleobases. In the present study, we characterized the transport of a variety of nucleosides and nucleobases via recombinant mouse ENT2 (mENT2). Cloned mENT2 mediated the uptake of nucleosides and purine nucleobases, but not pyrimidine nucleobases. The mENT2-mediated uptake of adenosine was significantly inhibited by nucleosides and nucleobases, irrespective of purine and pyrimidine. The K(m) values for the uptake of nucleosides and purine nucleobases mediated by mENT2 varied between 1.24 and 16.3 microM, and the transport clearances of adenosine and hypoxanthine via the transporter were greater than those of other substrates. Therefore, we concluded that mENT2 is nucleoside and purine nucleobase transporter, and pyrimidine nucleobases are blockers for the transporter, differing from hENT2 and rENT2 that were reported to also transport pyrimidine nucleobases.