Semi-Synthetic Ingenol Derivative from Euphorbia tirucalli Inhibits Protein Kinase C Isotypes and Promotes Autophagy and S-phase Arrest on Glioma Cell Lines.

The identification of signaling pathways that are involved in gliomagenesis is crucial for targeted therapy design. In this study we assessed the biological and therapeutic effect of ingenol-3-dodecanoate (IngC) on glioma. IngC exhibited dose-time-dependent cytotoxic effects on large panel of glioma cell lines (adult, pediatric cancer cells, and primary cultures), as well as, effectively reduced colonies formation. Nevertheless, it was not been able to attenuate cell migration, invasion, and promote apoptotic effects when administered alone. IngC exposure promoted S-phase arrest associated with p21CIP/WAF1 overexpression and regulated a broad range of signaling effectors related to survival and cell cycle regulation. Moreover, IngC led glioma cells to autophagy by LC3B-II accumulation and exhibited increased cytotoxic sensitivity when combined to a specific autophagic inhibitor, bafilomycin A1. In comparison with temozolomide, IngC showed a mean increase of 106-fold in efficacy, with no synergistic effect when they were both combined. When compared with a known compound of the same class, namely ingenol-3-angelate (I3A, Picato®), IngC showed a mean 9.46-fold higher efficacy. Furthermore, IngC acted as a potent inhibitor of protein kinase C (PKC) activity, an emerging therapeutic target in glioma cells, showing differential actions against various PKC isotypes. These findings identify IngC as a promising lead compound for the development of new cancer therapy and they may guide the search for additional PKC inhibitors.

Purified Dry Paullinia cupana (PC-18) Extract for Chemotherapy-Induced Fatigue: Results of Two Double-Blind Randomized Clinical Trials.

Fatigue is frequent among oncologic patients. Unpurified Paullinia cupana dry extract showed encouraging results for chemotherapy-induced fatigue in our previous studies. We report two randomized, double-blind studies with a standardized dry purified Paullinia cupana extract named PC-18. For both studies, we recruited early breast cancer patients who had an increase in their fatigue scores after their first cycle of adjuvant chemotherapy. In the first study, we compared an oral dose of 37.5 mg of PC-18 twice daily with placebo. In the second study, we examined PC-18 at either 7.5 or 12.5 mg orally twice daily versus placebo. In both studies, PC-18 was not superior to placebo as assessed by both Chalder and Brief Fatigue Inventory (BFI) fatigue questionnaires, probably reflecting unexpectedly good placebo antifatigue activity. Since all capsules employed in both studies contained about 100 mg of magnesium silicate as an excipient, we retrospectively evaluated frozen serum samples from the second study and found a significant increase in magnesium levels after patients received placebo. By multivariate analysis, higher prerandomization magnesium levels and higher BFI scores together with the use of a 12.5 mg dose of PC-18 all correlated significantly with higher posttreatment BFI scores. We observed no significant toxicities in any of the trials. We conclude that the absence of differences between PC-18 and placebo may be due to the unexpectedly high antifatigue activity of the placebo in these studies. Further studies evaluating the role of magnesium supplementation for chemotherapy-induced fatigue are needed.

Reactivation of latent HIV-1 by new semi-synthetic ingenol esters.

The ability of HIV to establish long-lived latent infection is mainly due to transcriptional silencing of viral genome in resting memory T lymphocytes. Here, we show that new semi-synthetic ingenol esters reactivate latent HIV reservoirs. Amongst the tested compounds, 3-caproyl-ingenol (ING B) was more potent in reactivating latent HIV than known activators such as SAHA, ingenol 3,20-dibenzoate, TNF-α, PMA and HMBA. ING B activated PKC isoforms followed by NF-κB nuclear translocation. As virus reactivation is dependent on intact NF-κB binding sites in the LTR promoter region ING B, we have shown that. ING B was able to reactivate virus transcription in primary HIV-infected resting cells up to 12 fold and up to 25 fold in combination with SAHA. Additionally, ING B promoted up-regulation of P-TEFb subunits CDK9/Cyclin T1. The role of ING B on promoting both transcription initiation and elongation makes this compound a strong candidate for an anti-HIV latency drug combined with suppressive HAART.

Euphol, a tetracyclic triterpene produces antinociceptive effects in inflammatory and neuropathic pain: the involvement of cannabinoid system.

Persistent pains associated with inflammatory and neuropathic states are prevalent and debilitating diseases, which still remain without a safe and adequate treatment. Euphol, an alcohol tetracyclic triterpene, has a wide range of pharmacological properties and is considered to have anti-inflammatory action. Here, we assessed the effects and the underlying mechanisms of action of euphol in preventing inflammatory and neuropathic pain. Oral treatment with euphol (30 and 100 mg/kg) reduced carrageenan-induced mechanical hyperalgesia. Likewise, euphol given through the spinal and intracerebroventricular routes prevented mechanical hyperalgesia induced by carrageenan. Euphol consistently blocked the mechanical hyperalgesia induced by complete Freund's adjuvant, keratinocyte-derived chemokine, interleukin-1ß, interleukin-6 and tumor necrosis factor-alpha associated with the suppression of myeloperoxidase activity in the mouse paw. Oral treatment with euphol was also effective in preventing the mechanical nociceptive response induced by ligation of the sciatic nerve and also significantly reduced the levels and mRNA of cytokines/chemokines in both paw and spinal cord tissues following i.pl. injection of complete Freund's adjuvant. In addition, the pre-treatment with either CB1R or CB2R antagonists, as well as the knockdown gene of the CB1R and CB2R, significantly reversed the antinociceptive effect of euphol. Interestingly, even in higher doses, euphol did not cause any relevant action in the central nervous system. Considering that few drugs are currently available for the treatment of chronic pain states, the present results provided evidence that euphol constitutes a promising molecule for the management of inflammatory and neuropathic pain states.

Euphol prevents experimental autoimmune encephalomyelitis in mice: evidence for the underlying mechanisms.

Multiple sclerosis (MS) is a severe chronic T cell-mediated autoimmune inflammatory disease of the central nervous system (CNS), the existing therapy of which is only partially effective and is associated with undesirable side effects. Euphol, an alcohol tetracyclic triterpene, has a wide range of pharmacological properties and is considered to have anti-inflammatory action. However there are no reports about the effects and mechanisms of euphol in experimental autoimmune encephalomyelitis (EAE), an established model of MS. Here we report the effects and the underlying mechanisms of action of euphol in EAE. Euphol (1-10mg/kg) was administered orally at different time-points of EAE. Immunological and inflammatory responses were evaluated by real-time PCR, Western blot and flow cytometry assays. We provide evidence that euphol significantly attenuates neurological signs of EAE. These beneficial effects of euphol seem to be associated with the down-regulation of mRNA and protein expression of some pro-inflammatory mediators such as TNF-α, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in the CNS. Furthermore, in vitro, euphol consistently inhibited the T cell-mediated immune response including the production of T(H)1 and T(H)17 cytokines in spleen cells of untreated EAE animals. Likewise, oral euphol treatment inhibited the infiltration of T(H)17 myelin-specific cells into the CNS through the adhesion molecule, lymphocyte function-associated antigen 1 (LFA-1). Our findings reveal that oral administration of euphol consistently reduces and limits the severity and development of EAE. Therefore, euphol might represent a potential molecule of interest for the treatment of MS and other T(H)17 cell-mediated inflammatory diseases.