2,5-hexanedione induces bone marrow mesenchymal stem cell apoptosis via inhibition of Akt/Bad signal pathway

2,5-Hexanedione induced apoptosis in rat spinal cord neurons and VSC4.1 cells via the proNGF/p75NTR and JNK pathways

Increasing evidence suggests that n-hexane induces nerve injury via neuronal apoptosis induced by its active metabolite 2,5-hexanedione (HD). However, the underlying mechanism remains unknown. Studies have confirmed that pro-nerve growth factor (proNGF), a precursor of mature nerve growth factor (mNGF), might activate apoptotic signaling by binding to p75 neurotrophin receptor (p75NTR) in neurons. Therefore, we studied the mechanism of the proNGF/p75NTR pathway in HD-induced neuronal apoptosis. Sprague-Dawley (SD) rats were injected with 400 mg/kg HD once a day for 5 weeks, and VSC4.1 cells were treated with 10, 20, and 40 mM HD in vitro. Results showed that HD effectively induced neuronal apoptosis. Moreover, it up-regulated proNGF and p75NTR levels, activated c-Jun N-terminal kinase (JNK) and c-Jun, and disrupted the balance between B-cell lymphoma-2 (Bcl-2) and Bcl-2-associated X protein (Bax). Our findings revealed that the proNGF/p75NTR signaling pathway was involved in HD-induced neuronal apoptosis; it can serve as a theoretical basis for further exploration of the neurotoxic mechanisms of HD.

Discovery of novel dihydroartemisinin-cinnamic hybrids inducing lung cancer cells apoptosis via inhibition of Akt/Bad signal pathway

A series of dihydroartemisinin-cinnamic acid hybrids were designed, synthesized and evaluated. Most of the tested compounds showed enhanced anti-proliferative activities than artemisinin and dihydroartemisinin, among which 16 g had the superior potency with IC₅₀ values ranging from 5.07 μM to 7.88 μM against four tested cancer cell lines. The cell cycle arrest revealed that 16 g induced A549 cell cycle arrest at G0/G1 phase via regulation of G1-related protein expression (Cdk4). Further mechanism studies reveal that 16 g induced A549 cells apoptosis via inhibiting Akt/Bad pathway. Moreover, 16 g depolarized the mitochondria membrane potentials and induced ROS generation in A549. Additionally, 16 g blocked migration of A549 cells in a concentration-dependent manner. What's more, 16 g is barely nontoxic to zebrafish embryos. Overall, the cell cycle arrest, inhibition of Akt/Bad signal pathway, ROS generation and migration blocked might explain the potent anti-proliferative activities of these compounds.

Nanomorphological and mechanical reconstruction of mesenchymal stem cells during early apoptosis detected by atomic force microscopy

Stem cell apoptosis exists widely in embryonic development, tissue regeneration, repair, aging and pathophysiology of disease. The molecular mechanism of stem cell apoptosis has been extensively investigated. However, alterations in biomechanics and nanomorphology have rarely been studied. Therefore, an apoptosis model was established for bone marrow mesenchymal stem cells (BMSCs) and the reconstruction of the mechanical properties and nanomorphology of the cells were investigated in detail. Atomic force microscopy (AFM), scanning electron microscopy (SEM), laser scanning confocal microscopy (LSCM), flow cytometry and Cell Counting Kit-8 analysis were applied to assess the cellular elasticity modulus, geometry, nanomorphology, cell surface ultrastructure, biological viability and early apoptotic signals (phosphatidylserine, PS). The results indicated that the cellular elastic modulus and volume significantly decreased, whereas the cell surface roughness obviously increased during the first 3 h of cytochalasin B (CB) treatment. Moreover, these alterations preceded the exposure of biological apoptotic signal PS. These findings suggested that cellular mechanical damage is connected with the apoptosis of BMSCs, and the alterations in mechanics and nanomorphology may be a sensitive index to detect alterations in cell viability during apoptosis. The results contribute to further understanding of apoptosis from the perspective of cell mechanics.

The ginsenoside Rk3 exerts anti-esophageal cancer activity in vitro and in vivo by mediating apoptosis and autophagy through regulation of the PI3K/Akt/mTOR pathway

The rare ginsenoside Rk3 is a bioactive component derived from ginseng and Panax notoginseng that has been proven to possess anti-lung cancer activity. However, the effect of Rk3 on human esophageal cancer has not yet been reported. In this study, we aimed to explore its anticancer curative effect and potential molecular mechanisms in the Eca109 and KYSE150 cell lines. We found that Rk3 was able to significantly repress cell proliferation and colony formation in both Eca109 and KYSE150 cells in vitro. In the KYSE150 xenograft model, Rk3 obviously inhibited tumor growth and exhibited little toxicity in organs. Moreover, Rk3 could trigger G1 phase arrest and induce apoptosis and autophagy. Interestingly, apoptosis induced by Rk3 could be partly abrogated by 3-MA (an autophagy inhibitor), implying that autophagy could enhance apoptosis. Further studies indicated that pretreatment with the Akt inhibitor GSK690693 or the mTOR inhibitor rapamycin promoted Rk3-induced apoptosis and autophagy, demonstrating that the PI3K/Akt/mTOR pathway is related to Rk3-induced apoptosis and autophagy. In conclusion, the present study is the first to clarify that Rk3 can inhibit Eca109 and KYSE150 cell proliferation through activating apoptosis and autophagy by blocking the PI3K/Akt/mTOR pathway, suggesting that Rk3 may be a promising antitumor agent for esophageal cancer. In addition, this study provides ideas and an experimental basis for further research on the anti-esophageal cancer effects of the ginsenoside Rk3 and its mechanism.

Induction of Apoptosis and Inhibition of Epithelial Mesenchymal Transition by α-Mangostin in MG-63 Cell Lines

Osteosarcoma is the most common bone primary malignant tumor and nearly 30% of patients still die from osteosarcoma due to metastasis or recurrence. Thus, it is necessary to develop effective new chemotherapeutic agents for osteosarcoma treatment. α-Mangostin is a xanthone derivative shown to have antioxidant and anticarcinogen properties. However, the molecular mechanisms underlying the antimetastatic effects of osteosarcoma remain unclear. In metastasis progression, epithelial mesenchymal transition (EMT) is a process that plays important roles in development, cell polarity, and increased invasion and migration. This study focused on the induction of apoptosis and inhibition of EMT process by α-mangostin in human osteosarcoma cell line MG63. α-Mangostin treatments on MG63 cells not only showed the several lines of evidence of apoptotic cell death but also inhibited cell migration, invasion, and EMT-inducing transcription factor. In conclusion, we demonstrate that the α-mangostin induces apoptosis via mitochondrial pathway and suppresses metastasis of osteosarcoma cells by inhibiting EMT.