Erianin, a natural product derived from Dendrobium chrysotoxum, has exhibited potential antitumor activity in various malignancies, including hepatocarcinoma, melanoma, and promyelocytic leukemia. Here we explored the effects of erianin on osteosarcoma (OS) in vitro and in vivo and further elucidated the underlying molecule mechanisms. In this study, we found that erianin potently suppressed cell viability in various OS cell lines. Treatment with erianin induced G2/M-phase arrest, apoptosis, and autophagy in OS cells. Further studies showed that erianin-induced apoptosis and autophagy was attributed to reactive oxygen species (ROS), as N-acetyl cysteine (NAC), an ROS scavenger, attenuated them. Moreover, we found that erianin induced activation of c-Jun N-terminal kinase (JNK) signal pathway, which was also blocked by NAC. Downregulation of JNK by its specific inhibitor SP600125 could attenuate apoptosis and autophagy induced by erianin. Finally, erianin in vivo markedly reduced the growth with little organ-related toxicity. In conclusion, erianin induced cell cycle G2/M-phase arrest, apoptosis, and autophagy via the ROS/JNK signaling pathway in human OS. In light of these results, erianin may be a promising agent for anticancer therapy against OS.

Signal transducer and activator of transcription 3(STAT3) is an emerging target for cancer therapy. In this study, we identify Toosendanin (TSN) is an effective inhibitor of STAT3, leading to the impediment of various oncogenic processes in osteosarcoma. TSN selectively inactivates phospho-STAT3 (Tyr-705); subsequent molecular docking and in vitro SPR analysis uncover TSN directly binds to the SH2 domain of STAT3. Consequently, TSN blocks STAT3 dimerization and impairs the complex formation of STAT3 and epidermal growth factor receptor (EGFR). In an animal tumor model study, TSN is well tolerated, inhibits osteosarcoma growth and metastasis. In another osteosarcoma patient-derived xenografts (PDX) model, we find TSN triggers strong inhibitory effects on patient-derived tumors. Further studies show that TSN also displays activity against other solid tumors. Our preclinical work therefore supports that TSN acts as a novel inhibitor of STAT3 that blocks tumorigenesis in ostoesarcoma.

The auditory portion of the inner ear, the cochlea, is an ideal organ for local gene transfection owing to its relative isolation. Various carriers have been tested for cochlear gene transfection. To date, viral vectors appear to have much higher transfection efficacy than non-viral mechanisms. Among these vectors, recombinant adeno-associated virus (rAAV) vectors have several advantages such as being non-pathogenic and the ability to produce prolonged gene expression in various cell types. However, rAAV vectors cannot pass through the intact round window membrane (RWM), otherwise a very attractive approach to access the human inner ear. In this study, performed in guinea-pigs, we describe a method to increase the permeability of RWM to rAAV vectors by partial digestion with collagenase solution. Elevated delivery of rAAV across the partially digested RWM increased transfection efficacy to a satisfactory level, even though it was still lower than that achieved by direct cochleostomy injection. Functional tests (auditory brainstem responses) showed that this enzymatic manipulation did not cause permanent hearing loss if applied appropriately. Morphological observations suggested that the damage to RWM caused by partial digestion healed within four weeks. Taken together, these findings suggest that partial digestion of the RWM is a safe and effective method for increasing the transfection of cochlear sensory cells with rAAV.