Ingenol mebutate treatment for actinic cheilitis: clinical, histopathological and p53 profile of 14 cases.

INTRODUCTION: Actinic cheilitis (AC) is part of a spectral disease of keratinocyte carcinomas considered by some authors an early stage of in situ squamous cell carcinoma. Treatment options for AC can be lesion and field-directed therapies. Ingenol mebutate (IM) induces rapid and direct cell death and immune responses being able to destruct dysplastic cells. MATERIALS AND METHODS: This study enrolled patients with AC to receive IM gel 0.015% for self-application on the lower lip for 3 consecutive days. A biopsy was performed before and after treatment for histopathological and immunohistochemical evaluation. Local skin reactions (LSR) were evaluated. The level of significance considered was 5%. RESULTS: Fourteen patients were enrolled. All LSR had a complete resolution for up to 2 weeks. The most common adverse events were burning sensation, angular cheilitis, and pain. There was an improvement of more than 80% in patients' subjective evaluation. There was no statistically significant histopathological response since all patients remained with mild dysplasia. No reduction in the P53 expression was observed in the current study. CONCLUSIONS: Despite being a safe therapeutic method, the absence of histopathological or immunohistochemical response suggests that clinical improvement may not be accompanied by histopathological cure for AC treated with IM.

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.

Modified ingenol semi-synthetic derivatives from Euphorbia tirucalli induce cytotoxicity on a large panel of human cancer cell lines.

The latex from Euphorbia tirucalli is used in Brazil as a folk medicine for several diseases, including cancer. Recently, we showed a cytotoxic activity of E. tirucalli euphol in a wide range of cancer cell lines. Moreover, we showed that euphol inhibits proliferation, motility and colony formation in pancreatic cancer cells, induces autophagy and sensitizes glioblastoma cells to temozolomide cytotoxicity. Herein, we report in vitro activity of three semi-synthetic ingenol compounds derived from E. tirucalli, IngA (ingenol-3-trans-cinnamate), IngB (ingenol-3-hexanoate) and IngC (ingenol-3-dodecanoate), against a large panel of human cancer cell lines. Antineoplastic effects of the three semi-synthetic compounds were assessed using MTS assays on 70 cancer cell lines from a wide array of solid tumors. Additionally, their antitumor potential was compared with known compounds of the same class, namely ingenol-3-angelate (Picato®) and ingenol 3,20-dibenzoate and in combination with standard chemotherapeutic agents. We observed that IngA, B, and C exhibited dose-dependent cytotoxic effects. Amongst the semi-synthetic compounds, IngC displayed the best activity across the tumor cell lines. In comparison with ingenol-3-angelate and ingenol 3,20-dibenzoate, IngC showed a mean of 6.6 and 3.6-fold higher efficacy, respectively, against esophageal cancer cell lines. Besides, IngC sensitized esophageal cancer cells to paclitaxel treatment. In conclusion, the semi-synthetic ingenol compounds, in particular, IngC, demonstrated a potent antitumor activity on all cancer cell lines evaluated. Although the underlying mechanisms of action of IngC are not elucidated, our results provide insights for further studies suggesting IngC as a putative therapy for cancer treatment.

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.