Cell size and cell cycle progression: the cyclin-dependent kinase link in green algae

miRNA omics reveal neferine induces apoptosis through Ca2+mediated endoplasmic reticulum stress pathway in human endometrial cancer

BACKGROUND

Endometrial cancer (EC) as one of the most prevalent malignancies in the female reproductive system, usually has a poor diagnosis and unfavorable health effects. Neferine (Nef), derived from the edible and medicinal lotus seed, has been known for its functional activity; however, its anti-cancer mechanism for EC remains elusive.

PURPOSE

We explored the potential anti-cancer effects and underlying molecular mechanisms of Nef on EC.

METHODS

The cytotoxicity was tested using MTT, and the cell cycle, apoptosis, Ca2+ levels, and the mitochondrial membrane potential (MMP) were observed through flow cytometry. After Nef treatment, differences in miRNA expression were identified using miRNA-seq data. Furthermore, western blot and immunohistochemistry (IHC) were employed to identify the proteins associated with apoptosis in both mice and cells.

RESULTS

Nef treatment led to Ishikawa cell apoptosis and blocked cell proliferation in the G2/M phase. In total, 101 significantly different miRNA (p 〈 0.05 and |logFC| 〉 1) were obtained and subjected to GO and KEGG enrichment analysis, which revealed the Ca2+ and PI3K/AKT signaling pathways pertaining to apoptosis. Nef treatment significantly changed intracellular Ca2+ levels and MMP, activating the endoplasmic reticulum stress (ERS) pathway and the expression of key proteins in the mitochondrial pathway. In addition, Nef also inhibited the expression of key proteins in the PI3K/AKT pathway, causing cell apoptosis. Moreover, in mouse tumor tissues, the expression of CHOP, Bcl-2, Caspase 3, Cyto-c, and p-AKT was also consistent with the results in vitro.

CONCLUSION

Nef could block the cell cycle and induce the activation of the mitochondrial apoptotic pathway involving the Ca2+-mediated ERS pathway and the PI3K/AKT pathway, thereby inducing apoptosis in EC cells, confirming the potential role of Nef in the prevention and treatment of EC.

Saikosaponin D exerts cytotoxicity on human endometrial cancer ishikawa cells by inducing apoptosis and inhibiting metastasis through MAPK pathways

Saikosaponin D (SSD) is one of plant secondary metabolic active substance with effective anti-tumor ability; however, the toxicity of Saikosaponin D on human endometrial cancer Ishikawa cells is still unclear. Our results revealed that SSD displayed cytotoxicity on the Ishikawa cell with an IC₅₀ = 15.69 μM, but was non-toxic to the human normal cell line HEK293. SSD could upregulate p21 and Cyclin B to keep cells in the G2/M stage. In addition, it activated the death receptor and mitochondrion routes to induce apoptosis in Ishikawa cells. The transwell chamber and wound healing results showed that SSD inhibited the cell migration and invasion. In addition, we found that it was closely related to the MAPK cascade pathway, and it could mediate the three classical MAPK pathways to block cell metastasis. In conclusion, SSD could be potentially beneficial as a natural secondary metabolite in preventing and treating endometrial carcinoma.

Aromatic hydrocarbon receptors in mitochondrial biogenesis and function

Mitochondria are ubiquitous membrane-bound organelles that not only play a key role in maintaining cellular energy homeostasis and metabolism but also in signaling and apoptosis. Aryl hydrocarbons receptors (AhRs) are ligand-activated transcription factors that recognize a wide variety of xenobiotics, including polyaromatic hydrocarbons and dioxins, and activate diverse detoxification pathways. These receptors are also activated by natural dietary compounds and endogenous metabolites. In addition, AhRs can modulate the expression of a diverse array of genes related to mitochondrial biogenesis and function. The aim of the present review is to analyze scientific data available on the AhR signaling pathway and its interaction with the intracellular signaling pathways involved in mitochondrial functions, especially those related to cell cycle progression and apoptosis. Various evidence have reported the crosstalk between the AhR signaling pathway and the nuclear factor κB (NF-κB), tyrosine kinase receptor signaling and mitogen-activated protein kinases (MAPKs). The AhR signaling pathway seems to promote cell cycle progression in the absence of exogenous ligands, whereas the presence of exogenous ligands induces cell cycle arrest. However, its effects on apoptosis are controversial since activation or overexpression of AhR has been observed to induce or inhibit apoptosis depending on the cell type. Regarding the mitochondria, although activation by endogenous ligands is related to mitochondrial dysfunction, the effects of endogenous ligands are not well understood but point towards antiapoptotic effects and inducers of mitochondrial biogenesis.

Cytoklepty in the plankton: A host strategy to optimize the bioenergetic machinery of endosymbiotic algae

Endosymbioses have shaped the evolutionary trajectory of life and remain ecologically important. Investigating oceanic photosymbioses can illuminate how algal endosymbionts are energetically exploited by their heterotrophic hosts and inform on putative initial steps of plastid acquisition in eukaryotes. By combining three-dimensional subcellular imaging with photophysiology, carbon flux imaging, and transcriptomics, we show that cell division of endosymbionts (Phaeocystis) is blocked within hosts (Acantharia) and that their cellular architecture and bioenergetic machinery are radically altered. Transcriptional evidence indicates that a nutrient-independent mechanism prevents symbiont cell division and decouples nuclear and plastid division. As endosymbiont plastids proliferate, the volume of the photosynthetic machinery volume increases 100-fold in correlation with the expansion of a reticular mitochondrial network in close proximity to plastids. Photosynthetic efficiency tends to increase with cell size, and photon propagation modeling indicates that the networked mitochondrial architecture enhances light capture. This is accompanied by 150-fold higher carbon uptake and up-regulation of genes involved in photosynthesis and carbon fixation, which, in conjunction with a ca.15-fold size increase of pyrenoids demonstrates enhanced primary production in symbiosis. Mass spectrometry imaging revealed major carbon allocation to plastids and transfer to the host cell. As in most photosymbioses, microalgae are contained within a host phagosome (symbiosome), but here, the phagosome invaginates into enlarged microalgal cells, perhaps to optimize metabolic exchange. This observation adds evidence that the algal metamorphosis is irreversible. Hosts, therefore, trigger and benefit from major bioenergetic remodeling of symbiotic microalgae with potential consequences for the oceanic carbon cycle. Unlike other photosymbioses, this interaction represents a so-called cytoklepty, which is a putative initial step toward plastid acquisition.