Calmodulin/CaMKII-γ mediates prosurvival capability in apicidin-persistent hepatocellular carcinoma cells via ERK1/2/CREB/c-fos signaling pathway

NETO2 promotes melanoma progression via activation of the Ca2+/CaMKII signaling pathway

Melanoma is the most aggressive cutaneous tumor. Neuropilin and tolloid-like 2 (NETO2) is closely related to tumorigenesis. However, the functional significance of NETO2 in melanoma progression remains unclear. Herein, we found that NETO2 expression was augmented in melanoma clinical tissues and associated with poor prognosis in melanoma patients. Disrupting NETO2 expression markedly inhibited melanoma proliferation, malignant growth, migration, and invasion by downregulating the levels of calcium ions (Ca²⁺) and the expression of key genes involved in the calcium signaling pathway. By contrast, NETO2 overexpression had the opposite effects. Importantly, pharmacological inhibition of CaMKII/CREB activity with the CaMKII inhibitor KN93 suppressed NETO2-induced proliferation and melanoma metastasis. Overall, this study uncovered the crucial role of NETO2-mediated regulation in melanoma progression, indicating that targeting NETO2 may effectively improve melanoma treatment.

Butyrate Attenuates Hepatic Steatosis Induced by a High-Fat and Fiber-Deficient Diet via the Hepatic GPR41/43-CaMKII/HDAC1-CREB Pathway

SCOPE

Hepatic steatosis is a major health issue that can be attenuated by a healthy diet. This study investigates the effects and molecular mechanisms of butyrate, a dietary fiber metabolite of gut microbiota, on lipid metabolism in hepatocytes.

METHODS AND RESULTS

This study examines the effects of butyrate (0-8 mM) on lipid metabolism in primary hepatocytes. The results show that butyrate (2 mM) consistently inhibits lipogenic genes and activates lipid oxidation-related gene expression in hepatocytes. Furthermore, butyrate modulates lipid metabolism genes, reduces fat droplet accumulation, and activates the calcium/calmodulin-dependent protein kinase II (CaMKII)/histone deacetylase 1 (HDAC1)-cyclic adenosine monophosphate response element binding protein (CREB) signaling pathway in the primary hepatocytes and liver of wild-type (WT) mice, but not in G-protein-coupled receptor 41 (GPR41) knockout and 43 (GPR43) knockout mice. This suggests that butyrate regulated hepatic lipid metabolism requires GPR41 and GPR43. Finally, the study finds that dietary butyrate supplementation (5%) ameliorates hepatic steatosis and abnormal lipid metabolism in the liver of mice fed a high-fat and fiber-deficient diet for 15 weeks.

CONCLUSION

This work reveals that butyrate improves hepatic lipid metabolism through the GPR41/43-CaMKII/HDAC1-CREB pathway, providing support for consideration of butyrate as a dietary supplement to prevent the progression of NAFLD induced by the Western-style diet.

Calreticulin nuclear translocalization alleviates CaM/CaMKII/CREB signaling pathway to enhance chemosensitivity in HDAC inhibitor-resistant hepatocellular carcinoma cells

Calreticulin (CRT) is located in the endoplasmic reticulum (ER), it helps proteins fold correctly inside the ER, and acts as a modulator of Ca²⁺ homeostasis. Aberrant expression of CRT is implicated in several cancer types, qualifying CRT as a potential therapeutic target. However, it remains unclear how CRT affects specific oncogenic pathways. In this study, we used histone deacetylase inhibitors (HDACis) to establish drug-resistant liver cancer cells and further analyzed the molecular mechanism of development of drug resistance in those cells. The 2D gel electrophoresis and RT-PCR data showed that CRT was downregulated in HDACis-resistant cells by comparing with HA22T parental cells. We previously elucidated the development of drug-resistance in HCC cells via activation of PP1-eIF2α pathway, but not via ER stress pathway. Here, we show that thapsigargin induced ER stress through mechanism other than ER stress downstream protein GRP78-PERK to regulate CRT expression in HDACis-R cells. Moreover, the expression level of CRT was not the main cause of apoptosis in HDACis-resistant cells. Mechanistic studies identified the apoptosis factors in the nucleus-the HDACis-mediated overexpression of CRT, CRT translocation to the cell nucleus, and reduced CaM/CaMKII/CREB pathway-that led to chemosensitivity in HDACis-R HCC cells.

Drug repositioning: Using psychotropic drugs for the treatment of glioma

Psychotropic drugs can penetrate the blood-brain barrier and regulate the levels of neurotransmitters and neuromodulators such as γ-aminobutyric acid, glutamate, serotonin, dopamine, and norepinephrine in the brain, and thus influence neuronal activity. Neuronal activity in the tumor microenvironment can promote the growth and expansion of glioma. There is increasing evidence that in addition to their use in the treatment of mental disorders, antipsychotic, antidepressant, and mood-stabilizing drugs have clinical potential for cancer therapy. These drugs have been shown to inhibit the malignant progression of glioma by targeting signaling pathways related to cell proliferation, apoptosis, or invasion/migration or by increasing the sensitivity of glioma cells to conventional chemotherapy or radiotherapy. In this review, we summarize findings from preclinical and clinical studies investigating the use of antipsychotics, antidepressants, and mood stabilizers in the treatment of various types of cancer, with a focus on glioma; and discuss their presumed antitumor mechanisms. The existing evidence indicates that psychotropic drugs with established pharmacologic and safety profiles can be repurposed as anticancer agents, thus providing new options for the treatment of glioma.

Analysis of RHOA mutations and their significance in the proliferation and transcriptome of digestive tract cancer cells

The ras homolog family member A (RHOA) gene encodes a member of the Rho family of small GTPases and is known to function in reorganization of the actin cytoskeleton, which is associated with regulation of cell shape, attachment and motility. RHOA has been found to be recurrently mutated in gastrointestinal cancer; however, the functional significance of the mutated RHOA protein in digestive tract cancers remains to be uncovered. The aim of the present study was to understand the role of mutant RHOA in the proliferation and transcriptome of digestive tract cancer cells. Mutations of RHOA in one esophageal cancer cell line, OE19, eight gastric cancer cell lines, namely, AGS, GCIY, HGC-27, KATO III, MKN1, MKN45, SNU16 and SNU719, as well as two colon cancer cell lines, CCK-81 and SW948, were determined using Sanger sequencing. The results uncovered several mutations, including p.Arg5Gln and p.Tyr42Cys in CCK-81, p.Arg5Trp and p.Phe39Leu in SNU16, p.Gly17Glu in SW948, p.Tyr42Ser in OE19, p.Ala61Val in SNU719, p.Glu64del in AGS. Wild-type RHOA was identified in GCIY, HGC-27, KATO III, MKN1 and MKN45. Knockdown of RHOA using small interfering RNA attenuated the in vitro proliferation in the three-dimensional culture systems of GCIY, MKN1, OE19 and SW948, whereas no apparent changes were seen in CCK-81, HGC-27 and SNU719. Transcriptome analysis revealed that downregulation of the long non-coding RNA (lnc)-DERA-1 was observed in all tested cell lines following RHOA knockdown in the RHOA-mutated cell lines. Gene Ontology analysis showed that the genes associated with small molecule metabolic process, oxidation-reduction processes, protein kinase activity, transport, and cell junction were commonly downregulated in cells whose proliferation was attenuated by the knockdown of RHOA. These results suggested that certain RHOA mutations may result in upregulation of lnc-DERA-1 and genes associated with cellular metabolism and proliferation in digestive tract cancers.