Effects of thymoquinone and the curcumin analog EF-24 on the activity of the enzyme paraoxonase-1 in human glioblastoma cells U87MG.

The spices and aromatic herbs were used not only in cooking to add flavour and smell to dishes but also for medicinal use. Nigella sativa, also called black cumin, is one of the species that contains an important bioactive component, thymoquinone (TQ), which has antioxidant, anti-inflammatory, antimicrobial, and antidiabetic effects. Curcuma longa, which also includes curcumin, has numerous anti-cancer properties. However, the bioavailability of curcumin is lower than that of its analogs. An analog of curcumin (EF-24), which has better bioavailability than curcumin, is capable of exerting a high anti-cancer effect. In our study, we determined the effects of PON1 enzyme activity on the proliferation and aggressiveness of glioblastoma cancer treated with TQ and EF-24 from lysates of the glioblastoma cell line U87MG. The results were determined as increased PON1 activity after treatment with TQ and EF-24 in the U87MG cell line (p < 0.0001).

Differential in vitro inhibitory effects of anticancer drugs on tumor-associated carbonic anhydrase isozymes CA IX and CA XII.

Carbonic anhydrase IX (CA IX) and, to a lesser extent, carbonic anhydrase XII (CA XII) are highly overexpressed in hypoxic tumors. In this study, the inhibitory effects of 11 different anticancer drugs including paclitaxel, amethopterin, etoposide, irinotecan, gemcitabine, 5-fluorouracil, oxaliplatin, epirubicin, cisplatin and carboplatin on the tumor-associated carbonic anhydrase isozymes CA IX and CA XII and cytosolic carbonic anhydrases I and II have been investigated. SX.18MV-R Applied Photophysics stopped-flow instrument was used for measuring the initial velocities for the CO2 hydration reaction catalyzed by different CA isozymes, by following the change in the absorbance of a pH indicator. CA IX and CA XII were the most affected by carboplatin and cisplatin amongst the panel of anticancer drugs. Moreover, the cytosolic carbonic anhydrases I and II can also be affected. Consequently, CA IX and CA XII are interesting targets for anticancer drug development, although more selective and powerful CA inhibitors could prove useful for elucidating the role of the protein in hypoxic cancers, for controlling the pH imbalance in tumor cells and for developing diagnostic or therapeutic applications for the management of hypoxic tumors, generally unresponsive to classical chemo- and radiotherapy.