Impact of metformin on neocortical development during pregnancy: Involvement of ERK and p35/CDK5 pathways.

Metformin, the most commonly prescribed drug for the treatment of diabetes, is increasingly used during pregnancy to address various disorders such as diabetes, obesity, preeclampsia, and metabolic diseases. However, its impact on neocortex development remains unclear. Here, we investigated the direct effects of metformin on neocortex development, focusing on ERK and p35/CDK5 regulation. Using a pregnant rat model, we found that metformin treatment during pregnancy induces small for gestational age (SGA) and reduces relative cortical thickness in embryos and neonates. Additionally, we discovered that metformin inhibits neural progenitor cell proliferation in the sub-ventricular zone (SVZ)/ventricular zone (VZ) of the developing neocortex, a process possibly mediated by ERK inactivation. Furthermore, metformin induces neuronal apoptosis in the SVZ/VZ area of the developing neocortex. Moreover, metformin retards neuronal migration, cortical lamination, and differentiation, potentially through p35/CDK5 inhibition in the developing neocortex. Remarkably, compensating for p35 through in utero electroporation partially rescues metformin-impaired neuronal migration and development. In summary, our study reveals that metformin disrupts neocortex development by inhibiting neuronal progenitor proliferation, neuronal migration, cortical layering, and cortical neuron maturation, likely via ERK and p35/CDK5 inhibition. Consequently, our findings advocate for caution in metformin usage during pregnancy, given its potential adverse effects on fetal brain development.

Metformin alters dendrite development and synaptic plasticity in rat cortical neurons.

Synaptic plasticity is crucial as it dynamically molds the strength and connectivity of neural circuits, influencing learning, memory, and the development of neurological disorders. Metformin, a widely prescribed anti-diabetic medication, has been shown to readily cross the blood-brain barrier (BBB) and the placenta. However, its prolonged impact on neuronal morphology and functions remains underexplored. In this study, we investigated the influence of metformin on dendrite development and synaptic plasticity in embryonic brains and primary rat cortical neurons. Our findings reveal a negative modulation of dendrite development by metformin, as evidenced by altered dendritic arborization, impaired dendritic spine morphology and disruptions in synaptic plasticity, suggesting a potential link between metformin exposure and aberrations in neuronal connectivity. In addition, we extend our insights to the impact of maternal metformin exposure on embryonic brains, revealing a significant inhibition of dendrite development in E18.5 rat brains. In conclusion, this study adds to the expanding knowledge base on the non-metabolic effects of metformin, emphasizing the significance of assessing its potential influence on both neuronal structure and function. There is an urgent need for further investigations into the enduring impact of prolonged metformin administration on the structural and functional aspects of neurons.

Metformin inhibits nerve growth factor (NGF)-induced sympathetic neuron differentiation through p35/CDK5 inhibition.

The authors' previous research has shown the pivotal roles of Cyclin-dependent kinase 5 (CDK5) and its regulatory protein p35 in nerve growth factor (NGF)-induced differentiation of sympathetic neurons in PC12 cells. During the process of differentiation, neurons are susceptible to environmental influences, including the effects of drugs. Metformin is commonly used in the treatment of diabetes and its associated symptoms, particularly in diabetic neuropathy, which is characterized by dysregulation of the sympathetic neurons. However, the impacts of metformin on sympathetic neuronal differentiation remain unknown. In this study, we investigated the impact of metformin on NGF-induced sympathetic neuronal differentiation using rat pheochromocytoma PC12 cells as a model. We examined the regulation of TrkA-p35/CDK5 signaling in NGF-induced PC12 differentiation. Our results demonstrate that metformin reduces NGF-induced PC12 differentiation by inactivating the TrkA receptor, subsequently inhibiting ERK and EGR1. Inhibition of this cascade ultimately leads to the down-regulation of p35/CDK5 in PC12 cells. Furthermore, metformin inhibits the activation of the pre-synaptic protein Synapsin-I, a substrate of CDK5, in PC12 differentiation. Additionally, metformin alters axonal and synaptic bouton formation by inhibiting p35 at both the axons and axon terminals in fully differentiated PC12 cells. In summary, our study elucidates that metformin inhibits sympathetic neuronal differentiation in PC12 cells by disrupting TrkA/ERK/EGR1 and p35/CDK5 signaling. This research contributes to uncovering a novel signaling mechanism in drug response during sympathetic neuronal differentiation, enhancing our understanding of the intricate molecular processes governing this critical aspect of neurodevelopment.

Dinaciclib inhibits the growth of acute myeloid leukemia cells through either cell cycle-related or ERK1/STAT3/MYC pathways.

Although immature differentiation and uncontrolled proliferation of hematopoietic stem cells are thought to be the primary mechanisms of acute myeloid leukemia (AML), the pathophysiology in most cases remains unclear. Dinaciclib, a selective small molecule targeting multiple cyclin-dependent kinases (CDKs), is currently being evaluated in oncological clinical trials. Despite the proven anticancer potential of dinaciclib, the differential molecular mechanisms by which it inhibits the growth of different AML cell lines remain unclear. In the current study, we treated HL-60 and KG-1 AML cell lines with dinaciclib and investigated the potential mechanisms of dinaciclib-induced AML cell growth inhibition using flow cytometry and western blotting assays. Data from HL-60 and KG-1 AML cells were validated using human primary AML cells. The results showed that the growth inhibitory effect of dinaciclib was more sensitive in HL-60 cells (IC50: 8.46 nM) than in KG-1 cells (IC50: 14.37 nM). The protein decline in Cyclin A/B and CDK1 and cell cycle arrest in the G2/M phase were more profound in HL-60 cells, corresponding to its growth inhibition. Although the growth inhibition of KG-1 cells by dinaciclib was still pronounced, the cell cycle-associated proteins were relatively insensitive. In addition to cell cycle regulation, the activation/expression of ERK1/STAT3/MYC signaling was significantly reduced by dinaciclib in KG-1 cells compared with that in HL-60 cells. Regarding the results of primary AML cells, we observed ERK1/STAT3/MYC inhibition and cell cycle regulation in different patients. These findings suggest that the cell cycle-associated and ERK1/STAT3/MYC signaling pathways might be two distinct mechanisms by which dinaciclib inhibits AML cells, which could facilitate the development of combination therapy for AML in the future.

Antrodia salmonea Extracts Regulate p53-AR Signaling and Apoptosis in Human Prostate Cancer LNCaP Cells.

Antrodia salmonea (AS) is a genus of Antrodia, an epiphyte of Cunninghamia konishii in Taiwan. AS has been reported to have potential therapeutic effects on different diseases, including diarrhea, abdominal pain, and hypertension. AS has been reported to have anticancer effects on numerous cancer types, such as ovarian carcinoma and triple-negative breast cancer. Our previous studies demonstrated that antrocins and triterpenoids are possibly bioactive compositions. However, the effects of AS on prostate cancer remain unknown. Therefore, we investigated the role of AS in prostate cancer growth, apoptosis, and cell cycle regulation. The results showed that AS extracts significantly inhibited the proliferation of prostate cancer LNCaP cells in a dose-dependent manner and increased the levels of apoptotic markers (cleaved PARP and cleaved caspase 3/8/9). In addition, the cell cycle-related proteins CDK1, CDK2, CDK4, and their respective specific regulators Cyclin B1, Cyclin A, and Cyclin D were also affected. Besides, AS treatment increased p53 protein levels and slowed its degradation in LNCaP cells. Interestingly, we found that AS treatment reduced both total protein and Ser-81 phosphorylation levels of the androgen receptor (AR). Notably, the increase of nuclear p53 was accompanied by the down-regulation of AR, suggesting a reverse regulation between p53 and AR in LNCaP cells was triggered by AS treatment. These findings suggest that AS extracts trigger the apoptosis of prostate cancer cells through the reverse regulation of p53 and AR and elucidate that AS extracts might be a potential treatment for androgen-dependent prostate cancer in the near future.

Antrodia salmonea extract inhibits cell proliferation through regulating cell cycle arrest and apoptosis in prostate cancer cell lines.

Antrodia salmonea (AS) is a fungus, which belongs to a fungal family of Taiwanofungus salmoneus with the features of anti-oxidant, anti-inflammatory, and anticancer. Recent studies have shown that AS has anti-cancer functions in ovarian and breast cancer. However, the effects of AS on prostate cancer (PCa) proliferation remain unknown. Therefore, we investigated the role of AS in PCa proliferation through apoptosis, and cell cycle regulation in PCa cell lines. Our results showed that Antrodia salmonea extract (ASE) inhibited PCa cells growth with a dose-dependent manner. In addition, ASE decreased the anchorage-independent growth formation ability in PC3 cells. Moreover, ASE-induced cell growth inhibition in PCa cells (DU145, PC3) was correlated to decreased cell cycle-related proteins such as cyclin A/B and cyclin-dependent kinase CDK1/2/4, and increased cell cycle inhibitor proteins p21. Besides, ASE decreased the total protein level of epidermal growth factor receptor and its downstream signaling pathways Akt and Erk in both PCa cells. We found that apoptotic markers such as cleaved-PARP protein levels increased significantly in DU145 cells indicating ASE might induce apoptosis. In conclusion, our results suggest that ASE may have the ability to induce PCa cell death through regulating cell cycle arrest and apoptosis pathways.