eriocalyxin-b and Prostatic-Neoplasms

BACKGROUND Eriocalyxin B (EriB), a diterpenoid isolated from the plant Isodon eriocalyx, has been shown to possess anti-tumor properties. However, few systematic studies of the mechanism underlying the anti-tumor activity of Eriocalyxin B in prostate cancer cells have been published. The aim of this study was to investigate the effect of Eriocalyxin B on prostate cancer cells. MATERIAL AND METHODS In the present study, the PC-3 (androgen-independent) and 22RV1 (androgen-dependent) human prostate cancer cell lines were cultured with and without increasing doses of Eriocalyxin B. MTT assay was used to measure cell viability. Western blotting was performed to measure levels of proteins associated with apoptosis and autophagy. Flow cytometry was used to assess changes in cell apoptosis and cycle. Fluorescence microscopy was used to capture images of autophagy-related proteins. RESULTS Treatment of human prostate cancer cells with Eriocalyxin B resulted in apoptosis in a dose- and time-dependent manner. Eriocalyxin B also induced autophagy, with elevated LC3B-II protein expression and punctuate patterns. Additionally, autophagy protected prostate cancer cells from apoptosis induced by Eriocalyxin B, which was demonstrated by addition of chloroquine (CQ). Moreover, the results indicated that Eriocalyxin B could inhibit the phosphorylation of Akt and mTOR. Eriocalyxin B induced apoptosis and autophagy by inhibition of the Akt/mTOR pathway. CONCLUSIONS Eriocalyxin B induces apoptosis and autophagy involving the Akt/mTOR pathway in prostate cancer cells in vitro. These findings provide evidence for Eriocalyxin B as a potent therapeutic for the treatment of prostate cancer.

Topics: Apoptosis; Autophagy; Cell Line, Tumor; Cell Proliferation; Cell Survival; China; Diterpenes; Humans; Male; PC-3 Cells; Prostate; Prostatic Neoplasms; Proto-Oncogene Proteins c-akt; Signal Transduction; TOR Serine-Threonine Kinases

Three new, seco-ent-kaurane diterpenoids, laxiflorins A, B and C, together with four known diterpenoids eriocalyxin B, oriodonin, and maeocrystals A and B, were isolated from the leaves of Isodon eriocalyx var. laxiflora. Their structures were assigned by a combination of one- and two-dimensional NMR techniques and computer modeling calculations. Laxiflorin C displayed weak cytotoxic activity.

Topics: Antineoplastic Agents; Astrocytoma; Breast Neoplasms; Cell Line; Cell Survival; China; Diterpenes; Drug Screening Assays, Antitumor; Humans; KB Cells; Lung Neoplasms; Magnetic Resonance Spectroscopy; Male; Models, Molecular; Molecular Structure; Plants, Medicinal; Prostatic Neoplasms; Structure-Activity Relationship; Tumor Cells, Cultured