An Organofluorine Isoselenocyanate Analogue of Sulforaphane Affects Antimetabolite 5-Fluorouracil's Anticancer Activity: A Perspective for New Combinatory Therapy in Triple-Negative Breast Cancer.

Antimetabolites, especially 5-fluorouracil, are commonly used clinically to treat breast, colon, and other cancers. However, their side effects and inefficiency in monotherapy have prompted further searches for new combinations. Thus, the anticancer effect of 5-fluorouracil (5-FU) and the sulforaphane analogue, 4-isoselenocyanato-1-butyl 4'-fluorobenzyl sulfoxide (ISC), were tested in in vitro and in vivo models of triple-negative breast cancer (TNBC) as a new option for this treatment-resistant and aggressive type of breast cancer. A synergic interaction between 5-FU and ISC was observed in the TNBC in vitro model MDA-MB-231 cell line, which led to enhanced antiproliferative effects. The results of in vitro studies were confirmed by in vivo tests, which demonstrated stronger tumor growth inhibition and additive interactions between 5-FU and ISC in the murine TNBC model. Moreover, the results of the body mass and blood analysis showed the safety of the tested combination. The mechanistic study revealed that the combined treatment triggered apoptosis and necrosis, as well as inhibited cell migration.

Fluoroaryl analogs of sulforaphane - A group of compounds of anticancer and antimicrobial activity.

A series of new sulforaphane analogs bearing various (poly)fluoroaryl substituents bonded to the sulfinyl sulfur atom in place of the original methyl group and having different number of methylene groups in the central alkyl chain were synthesized and fully characterized. The new compounds were tested in vitro for their anticancer, antibacterial, antifungal and antiviral properties. Some of them demonstrated a much higher anticancer activity against selected lines of cancer: skin (MALME-3M), colon (HT-29) and breast (MCF7 and MDA-MB-231) cells than that exhibited by native sulforaphane (SFN). Related lines of untransformed (normal) cells, taken from the same organs as the cancer ones, i.e. MALME3, CRL-1790 and MCF10, respectively, were checked, which allowed for the determination of the selectivity indexes (SI). In certain cases, the latter exceeded 3.2. Concerning the antibacterial activity, gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) were susceptible to some newly synthesized SFN analogs, while the selected probiotic strains were from 10 to 100 fold more resistant to them, which gives a possibility of protection of symbiont strains during a potential therapy with such compounds. The antifungal activity of the new compounds possessing the fluorophenyl substituent was found to be higher than the activity of the parent SFN. In turn, most of the new compounds showed generally no anti-HIV activity. The influence of the particular structural differences in the new molecules, analogs of SFN, on their biological activity is discussed.

The Comparison of MTT and CVS Assays for the Assessment of Anticancer Agent Interactions.

Multiple in vitro tests are widely applied to assess the anticancer activity of new compounds, including their combinations and interactions with other drugs. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay is one of the most commonly used assays to assess the efficacy and interactions of anticancer agents. However, it can be significantly influenced by compounds that modify cell metabolism and reaction conditions. Therefore, several assays are sometimes used to screen for potential anticancer drugs. However, the majority of drug interactions are evaluated only with this single method. The aim of our studies was to verify whether the choice of an assay has an impact on determining the type of interaction and to identify the source of discrepancies. We compared the accuracy of MTT and CVS (crystal violet staining) assays in the interaction of two compounds characterized by similar anticancer activity: isothiocyanates (ITCs) and Selol. Confocal microscopy studies were carried out to assess the influence of these compounds on the reactive oxygen species (ROS) level, mitochondrial membrane potential, dead-to-live cell ratio and MTT-tetrazolium salt reduction rate. The MTT assay was less reliable than CVS. The MTT test of Selol and 2-oxoheptyl ITC, which affected the ROS level and MTT reduction rate, gave false negative (2-oxoheptyl ITC) or false positive (Selol) results. As a consequence, the MTT assay identified an antagonistic interaction between Selol and ITC, while the metabolism-independent CVS test identified an additive or synergistic interaction. In this paper, we show for the first time that the test assay may change the interpretation of the compound interaction. Therefore, the test method should be chosen with caution, considering the mechanism of action of the compound.

Organofluorine Isoselenocyanate Analogues of Sulforaphane: Synthesis and Anticancer Activity.

A series of previously unknown sulforaphane analogues with organofluorine substituents bonded to the sulfinyl sulfur atom, an isoselenocyanate moiety in place of the isothiocyanate group, the central sulfur atom in various oxidation states, and different numbers of methylene groups in the central alkyl chain were synthesized and fully characterized. All new compounds were tested for their biological properties in vitro and demonstrated much higher anticancer activity against two breast cancer cell lines than that shown by native sulforaphane; at the same time, the compounds were less toxic for normal cells. The influence of the particular structural changes in the molecules on the cytotoxicity is discussed.

New enantiomeric fluorine-containing derivatives of sulforaphane: synthesis, absolute configurations and biological activity.

Three pairs of enantiomers of the unknown sulforaphane analogs bearing organofluorine substituents bonded to the sulfinyl sulfur atom and having different number of methylene groups in the central carbon chain were synthesized and fully characterized, including determination of their absolute configurations. All the new compounds were tested in vitro for their cytotoxicity against melanoma cells to show increased activity in comparison with the natural sulforaphane. The influence of the particular structural changes in the molecule on the cytotoxicity is discussed.