br Inhibition of cytokines TNF a and interleukins
2.5.3. Inhibition of cytokines (TNF-a and interleukins)
TNF- a (Tumor necrosis factor alpha) which is produced in im-mune and tumor BQ-788 sodium salt plays a central role in inflammation, apoptosis, and cancer progression. Cell surface TNF-a can induce lysis in tumor cells or surrounding cells which induce the necrosis-like death phenotype. TNF-a can bind to its receptor to induce apoptosis. TNF-a has bivalent capacities with prod and anti-dtumorigenic profiles and thus is of great interest in the devel-opment of anti-cancer drugs [61e63].
Interleukins (IL) are a class inflammatory cytokines known to be linked to metastasis when overexpressed in a number of epithelial breast, lung and kidney tumors [64e67]. Some members of the ILs family have been reported to stimulate tumor growth and metas-tasis via a number of proteolytic interactions and through control of several MMPs expression and the expression of proangiogenic proteins such as VEGF [59,67,68]. We studied the inhibition of ILs by bimetallic compounds TieAu Titanocref (2), Titanofin (4) and monometallic Au compounds cref (1), fin (3) and Auranofin after 72 h of incubation at IC20 concentrations, we chose the 72 h time-point because no significant effect was observed after 24 h of in-cubation with the same concentrations (Fig. 6B). We found that the bimetallic compounds, gold monometallic compounds and aur-anofin inhibited IL-6 expression almost completely. Auranofin and Titanocref (2) also inhibited IL-5 expression while the inhibition by Titanofin (4) was more modest (89% Titanocref (2), 59% Titanofin (4) and 88% Auranofin). Auranofin was a better inhibitor for IL-8 while both bimetallic compounds Titanocref (2) and Titanofin (4) were much better IL-4 and IL-17A inhibitors. Titanocref (2), Tita-nofin (4) and monometallic Au cref (2) and fin (4) are particularly
strong inhibitors of IL-17A. Because IL-17A expression is associated with ER ( ) and triple negative tumor hyper proliferation and poor prognosis in breast cancer, IL-17 inhibitors are of clinical interest. Also, IL-17 promotes cancerous cell survival and invasiveness as well as angiogenesis. Auranofin, as previously reported, inhibits IL-6 , but we have observed that it also inhibits expression of IL-5 and IL-8 , all key players in inflammatory signaling. IL inhibitors are of further interest because they are known inducers of MMPs which are critical in metastasis [64,65,67].
2.5.4. Inhibition of matrix metalloproteases
Matrix metalloproteinases (MMPs) are a family of zinc-dependent extracellular remodeling endopeptidases that play a critical role in tumor growth and the complex processes of invasion and metastasis through proteolytic degradation of ECM, modifica-tions of the cell-cell, cell-ECM communication. Also, several MMPs have been shown to promote angiogenesis [60,68e70]. Matrix metalloproteinase inhibitors (MMPIs) have been developed and continue to be explored as viable therapeutic regiments to curb cancer progression [68,69,71]. The several members of the MMP family proteolytic factors are drive tumor induced inflammation signaling and angiogenesis most often in cooperation with mem-bers of the IL family [65,67,72,73]. We studied the inhibition of several MMPs of oncological interest (MMP-1, MMP-2, MMP-3, MMP-7, MMP-8, MMP-9) by bimetallic TieAu Titanocref (2), Tita-nofin (4), and monometallic Au cref (2), fin (3) and Auranofin. The protein expression of all the selected MMPs are inhibited by the bimetallic compounds except MMP-2 which is most inhibited by the monometallic compounds. For MMP-3 both the bimetallic and monometallic compounds achieve inhibition greater than 50%. The inhibition of MMP-7 is significant and equally inhibited by the bimetallic compounds while the monometallic compounds cause no inhibition (Fig. 7). Auranofin  and Titanofin (4) (to a slightly higher degree) inhibit the expression of MMP-9 while Titanocref (2) and the monometallic Au cref (2) and fin (3) do not have much of an effect.
It is evident from the changes in expression we have observed as
a result of treatment with Titanocref (2), Titanofin (4) and mono-metallic Au cref (2), fin (3) and Auranofin that while bimetallic compounds are most often more effective inhibitors than mono-metallic compounds, the latter do have a non-negligible IL(s) and MMP(s) inhibitory profile rendering them promising anti-cancer candidates (see fin 3).
Owing to the fact that there is limited understanding of the
pathways by which metallodrugs achieve efficacy, we performed for 72 h at IC20 a protein expression screen of our compounds’ ef-fects on eighty-four cancer-related proteins. We chose the 72 h