Morin Hydrate Sensitizes Hepatoma Cells and Xenograft Tumor towards Cisplatin by Downregulating PARP-1-HMGB1 Mediated Autophagy

The cross-talk between apoptosis and autophagy influences anticancer drug sensitivity and cellular death in various cancer cell lines. However, the fundamental mechanisms behind this phenomenon are still unidentified. We demonstrated anti-cancerous role of cisplatin (CP) and morin hydrate (Mh) as an individual and/or in combination (CP-Mh) in hepatoma cells and tumor model. Exposure of CP resulted in the production of intracellular reactive oxygen species (ROS)-mediated cellular vacuolization, expansion of mitochondria membrane and activation of endoplasmic reticulum (ER)-stress. Consequently, Cyt c translocation led to the increase of Bax/Bcl-2 ratio, which simultaneously triggered caspase-mediated cellular apoptosis. In addition, CP-induced PARP-1 activation led to ADP-ribosylation of HMGB1, which consequently developed autophagy as evident by the LC3I/II ratio. Chemically-induced inhibition of autophagy marked by increased cell death signified a protective role of autophagy against CP treatment. CP-Mh abrogates the PARP-1 expression and significantly reduced HMGB1-cytoplasmic translocation with subsequent inhibition of the HMGB1-Beclin1 complex formation. In the absence of PARP-1, a reduced HMGB1 mediated autophagy was observed followed by induced caspase-dependent apoptosis. To confirm the role of PARP-1-HMGB1 signaling in autophagy, we used the PARP-1 inhibitor, 4-amino-1,8-naphthalimide (ANI), HMGB1 inhibitor, ethyl pyruvate (EP), autophagy inhibitors, 3-methyl adenine (3-MA) and bafilomycin (baf) and small interfering RNAs (siRNA) to target Atg5 in combination of CP and Mh. Exposure to these inhibitors enhanced the sensitivity of HepG2 cells to CP. Collectively, our findings indicate that CP-Mh in combination served as a prominent regulator of autophagy and significant inducer of apoptosis that maintains a homeostatic balance towards HepG2 cells and the subcutaneous tumor model.

Effects of Locally Delivered Morin Hydrate on Iodoacetate-induced Temporomandibular Joint Osteoarthritis in Rats

Objectives: morin hydrate has been reported to possess many beneficial pharmacological potentialities including antioxidant and anti-osteoarthritic effects. The antiosteoarthritic properties of locally administrated morin have not been investigated. The objective of this study is to evaluate the locally delivered morin on the temporomandibular joint osteoarthritis in rat. Materials and methods: thirty young adult female Sprague Dawley rats were randomly arranged into three groups; control, osteoarthritis and osteoarthritis with morin. Both the iodoacetate for osteoarthritis induction and morin hydrate therapy were delivered unilaterally via intra-articular route. Results: morin reduced osteoarthritis manifestations with prominent thickening of both condylar fibrous layer and articular disc accompanied with discal cells hypertrophy that ultimately acquired chondrocytes features. The condylar cartilage matrix showed enhancement of extracellular matrix production with morin administration. Discussion: the present study has elucidated antiosteoarthritic effect of intraarticular injection of morin hydrate. Although morin has managed to prevent the propagation and advancing some of the recorded osteoarthritic manifestations; however, it showed some failure in managing others. The administration of morin hydrate modulated the structure of the joint rather than restore it back to its typical configuration. Conclusion: the morin hydrate administration to osteoarthritic animals showed relieve in some of osteoarthritic features and modulated the structure of some joint components to compensate the unhandled manifestations.KEYWORDSIodoacetate; Morin; Osteoarthritis; OARSI Score; Temporomandibular joint.