Prolactin receptor potentiates chemotherapy through miRNAs-induced G6PD/TKT inhibition in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies, with a notoriously dismal prognosis. As a competitive inhibitor of DNA synthesis, gemcitabine is the cornerstone drug for treating PDAC at all stages. The therapeutic effect of gemcitabine, however, is often hindered by drug resistance, and the underlying mechanisms remain largely unknown. It is unclear whether their response to chemotherapeutics is regulated by endocrine regulators, despite the association between PDAC risk and endocrine deregulation. Here, we show that prolactin receptor (PRLR) synergizes with gemcitabine in both in vitro and in vivo treatment of PDAC. Interestingly, PRLR promotes the expression of miR-4763-3p and miR-3663-5p, two novel miRNAs whose functions are unknown. Furthermore, the analysis of transcriptome sequencing data of tumors from lactating mouse models enriches the PPP pathway, a multifunctional metabolic pathway. In addition to providing energy, the PPP pathway mainly provides a variety of raw materials for anabolism. We demonstrate that two key enzymes of the pentose phosphate pathway (PPP), G6PD and TKT, are directly targeted by miR-4763-3p and miR-3663-5p. Notably, miR-4763-3p and miR-3663-5p diminish the nucleotide synthesis of the PPP pathway, thereby increasing gemcitabine sensitivity. As a result, PRLR harnesses these two miRNAs to suppress PPP and nucleotide synthesis, subsequently elevating the gemcitabine sensitivity of PDAC cells. Also, PDAC tissues and tumors from LSL-KrasG12D/+, LSL-Trp53R172H/+, and PDX1-cre (KPC) mice exhibit downregulation of PRLR. Bisulfite sequencing of PDAC tissues revealed that PRLR downregulation is due to epigenetic methylation. In this study, we show for the first time that the endocrine receptor PRLR improves the effects of gemcitabine by boosting two new miRNAs that block the PPP pathway and nucleotide synthesis by inhibiting two essential enzymes concurrently. The PRLR-miRNAs-PPP axis may serve as a possible therapeutic target to supplement chemotherapy advantages in PDAC.

A novel tRNA-derived fragment tRF-3023b suppresses inflammation in RAW264.7 cells by targeting Cul4a through NF-κB signaling.

The role of transfer RNA (tRNA)-derived fragment (tRF) in various diseases has been established. However, the effect of tRF-3023b on inflammation remains unclear. Inflammation was imitated in RAW264.7 cells by adding Lipopolysaccharide (LPS). Cells were first divided into control, LPS, and LPS + Bulleyaconitine A (BLA) groups. The contents of TNF-α, IL-6, and MCP-1 were quantified using ELISA. The levels of cyclooxygenase-2 (COX2), inducible nitric oxide synthase (iNOS), and the phosphorylation of nuclear factor-kappa B (NF-κB)-P65 (p-P65) were detected by Western blotting. RNA sequencing was utilized to find differentially expressed tRFs (DE-tRFs) among three groups. The levels of various tRFs were checked by quantitative real-time PCR (qRT-PCR). Cell cycle and apoptosis were checked by flow cytometry. Dluciferase reporter assay was applied to predict and confirm the interaction between tRF-3023b and Cullin 4A (Cul4a), subsequently RNA pull-down followed by mass spectrometry analysis were conducted. BLA treatment decreased the contents of TNF-α, IL-6, MCP-1, and the expression levels of COX2, iNOS, p-P65. We found 6 DE-tRFs in LPS + BLA group compared to LPS group, tRF-3023b was high expression in control and BLA groups, and the lowest in LPS group. Cul4a was a direct target of tRF-3023b. tRF-3023b mimic affected the cell cycle distribution, promoted cells apoptosis, and suppressed the TNF-α, IL-6, MCP-1, COX2, iNOS and p-P65. The suppression of Cul4a affected the cell cycle distribution, resulted in an increase of cell apoptosis while a decrease of TNF-α, IL-6, MCP-1, COX2, iNOS and p-P65. Furthermore, Cul4a overexpression reversed the effect of tRF-3023b mimic. Cul4a knockdown reversed the effect of tRF-3023b inhibitor. Our study positions tRF-3023b as a compelling candidate, through its interaction with Cul4a, the underlying mechanism on inflammation maybe related to NF-κB pathway. The study provides a basis for exploring new therapeutic strategies for inflammation.

Sesamolin Protects Mice From Ovariectomized Bone Loss by Inhibiting Osteoclastogenesis and RANKL-Mediated NF-κB and MAPK Signaling Pathways.

This article was submitted to Experimental Pharmacology and Drug Discovery, a section of the journal Frontiers in Pharmacology. Postmenopausal osteoporosis (PMOP), which increases the risk of fracture, is the most common bone disease in women. PMOP not only increases the risk of death but also imposes a financial burden on countless families. At present, most of the drugs used to treat osteoporosis have significant side effects, so it is important to find effective anti-osteoporosis medications without major side effects. Sesamolin (Ses) is a kind of natural lignan extracted from sesame oil. Many researches have shown that Ses has anti-inflammatory, antioxidative, and anticancer effects, however it is still unknown whether it has any effect on osteoporosis. In this research, we explored the therapeutic effect of Ses in the process of osteoclast formation and bone resorption and found that Ses effectively inhibited osteoclast formation in vitro through TRAcP staining and hydroxyapatite resorption assays. Through Western blot analysis of the NF-κB pathway, MAPK pathway, c-Fos and NFATc1, it was found that Ses not only effectively inhibited the activation of NF-κB and MAPK signaling pathways induced by RANKL but also significantly reduced the protein expression of c-Fos and NFATc1. Several genes specifically expressed in osteoclasts were determined by qPCR, and Ses was also found to play a significant inhibitory role on the expression of these genes. Besides, an osteoporosis model induced in ovariectomized (OVX) mice was employed to verify that Ses could effectively reduce bone loss caused by estrogen deficiency in vivo. In conclusion, Ses showed promise as a new treatment for postmenopausal osteoporosis.

Hederagenin protects mice against ovariectomy-induced bone loss by inhibiting RANKL-induced osteoclastogenesis and bone resorption.

AIMS: Postmenopausal osteoporosis and other osteolytic bone diseases are often caused by the elevation in osteoclastogenesis and/or increased osteoclastic bone resorption, leading to excessive bone loss. Hederagenin (Hed) is a pentacyclic triterpenoid saponin extracted from various natural medicinal plants and exhibits numerous biological activities and may offer benefits against bone-related conditions. We evaluated the effects of Hed on osteoclast formation and bone resorption in vitro and the in vivo therapeutic benefits in the mouse model of ovariectomy (OVX)-induced bone loss. MAIN METHODS: In vitro, osteoclast formation were determined by TRAcp staining; bone resorption were examined using Hydroxyapatite resorption assay and Podosomal actin belt formation assay; Related molecular mechanisms were determined by western blot assay. Construction of OVX mice by bilateral oophorectomy to simulate bone loss in vivo. KEY FINDINGS: In vitro cellular assays showed that Hed inhibited RANKL-induced osteoclast formation and osteoclast bone (hydroxyapatite) resorption as well as marker gene expression from BMM culture. Mechanistically, Hed attenuated RANKL-induced intracellular reactive oxygen species (ROS) production, and MAPK signaling pathway (ERK and p38) activation which curbed the downstream induction of c-Fos and NFATc1. Consistent with the in vitro findings, Hed administration effectively protected OVX mice from bone loss by reducing osteoclast number and activity on bone surface. SIGNIFICANCE: Our data provided promising evidence for the potential use of Hederagenin in the treatment of osteoclast-mediated osteolytic bone diseases such as postmenopausal osteoporosis.

Vindoline Inhibits RANKL-Induced Osteoclastogenesis and Prevents Ovariectomy-Induced Bone Loss in Mice.

Osteolytic bone diseases, for example postmenopausal osteoporosis, arise from the imbalances between osteoclasts and osteoblasts in the bone remodeling process, whereby osteoclastic bone resorption greatly exceeds osteoblastic bone formation resulting in severe bone loss and deterioration in bone structure and microarchitecture. Therefore, the identification of agents that can inhibit osteoclast formation and/or function for the treatment of osteolytic bone disease has been the focus of bone and orthopedic research. Vindoline (Vin), an indole alkaloid extracted from the medicinal plant Catharanthus roseus, has been shown to possess extensive biological and pharmacological benefits, but its effects on bone metabolism remains to be documented. Our study demonstrated for the first time, that Vin could inhibit osteoclast differentiation from bone marrow macrophages (BMMs) precursor cells as well as mature osteoclastic bone resorption. We further determined that the underlying molecular mechanism of action of Vin is in part due to its inhibitory effect against the activation of MAPK including p38, JNK, and ERK and intracellular reactive oxygen species (ROS) production. This effect ultimately suppressed the induction of c-Fos and NFATc1, which consequently downregulated the expression of the genes required for osteoclast formation and bone resorption. Consistent with our in vitro findings, in vivo administration of Vin protected mice against ovariectomy (OVX)-induced bone loss and trabecular bone deterioration. These results provided promising evidence for the potential therapeutic application of Vin as a novel treatment option against osteolytic diseases.

Status of vitamin D, antimicrobial peptide cathelicidin and T helper-associated cytokines in patients with diabetes mellitus and pulmonary tuberculosis.

Pulmonary tuberculosis (PTB) is a high burden infectious disease in China. The immune function is damaged in patients with diabetes mellitus (DM) who are easy to infect with Mycobacterium tuberculosis (Mtb). The growth of Mtb has been shown to be restrained following the administration of vitamin D and antimicrobial peptide cathelicidin (LL-37); however, the effect in patients with DM and PTB remains unclear. Vitamin D can regulate the immune system through Vitamin D receptors expressed in T helper (Th) cells. The aim of the present study was to analyze the status and correlations of vitamin D, LL-37 and Th-associated cytokines in patients with PTB or PTB with DM (DMPTB). Serum 25-hydroxyvitamin D3 [25(OH)D3] levels were measured by liquid chromatography-tandem mass spectrometry, while plasma LL-37 levels were analyzed using a solid-phase enzyme-linked immunosorbent assay. Flow cytometry was used to analyze the levels of Th cytokines, including Th1-associated IFN-γ, Th2-associated IL-4 and Th17-associated IL-17. The results revealed that patients with PTB and DMPTB were vitamin D deficient or had insufficient vitamin D levels. Furthermore, the levels of LL-37, IFN-γ, IL-4 and IL-17 were higher in the PTB and DMPTB groups when compared with the normal controls. These results indicated that vitamin D supplementation is necessary for PTB and DMPTB patients. In addition, LL-37, IFN-γ and IL-17 may be diagnostic indexes that become elevated in the compensatory response caused by Mtb infection. Vitamin D can regulate the immune status in patients suffering from PTB.