Adipocyte-derived IL-6 and leptin promote breast Cancer metastasis via upregulation of Lysyl Hydroxylase-2 expression

Background

Adipocytes make up the major component of breast tissue, accounting for 90% of stromal tissue. Thus, the crosstalk between adipocytes and breast cancer cells may play a critical role in cancer progression. Adipocyte-breast cancer interactions have been considered important for the promotion of breast cancer metastasis. However, the specific mechanisms underlying these interactions are unclear. In this study, we investigated the mechanisms of adipocyte-mediated breast cancer metastasis.

Methods

Breast cancer cells were cocultured with mature adipocytes for migration and 3D matrix invasion assays. Next, lentivirus-mediated loss-of-function experiments were used to explore the function of lysyl hydroxylase (PLOD2) in breast cancer migration and adipocyte-dependent migration of breast cancer cells. The role of PLOD2 in breast cancer metastasis was further confirmed using orthotopic mammary fat pad xenografts in vivo. Clinical samples were used to confirm that PLOD2 expression is increased in tumor tissue and is associated with poor prognosis of breast cancer patients. Cells were treated with cytokines and pharmacological inhibitors in order to verify which adipokines were responsible for activation of PLOD2 expression and which signaling pathways were activated in vitro.

Results

Gene expression profiling and Western blotting analyses revealed that PLOD2 was upregulated in breast cancer cells following coculture with adipocytes; this process was accompanied by enhanced breast cancer cell migration and invasion. Loss-of-function studies indicated that PLOD2 knockdown suppressed cell migration and disrupted the formation of actin stress fibers in breast cancer cells and abrogated the migration induced by following coculture with adipocytes. Moreover, experiments performed in orthotopic mammary fat pad xenografts showed that PLOD2 knockdown could reduce metastasis to the lung and liver. Further, high PLOD2 expression correlated with poor prognosis of breast cancer patients. Mechanistically, adipocyte-derived interleukin-6 (IL-6) and leptin may facilitate PLOD2 upregulation in breast cancer cells and promote breast cancer metastasis in tail vein metastasis assays. Further investigation revealed that adipocyte-derived IL-6 and leptin promoted PLOD2 expression through activation of the JAK/STAT3 and PI3K/AKT signaling pathways.

Conclusions

Our study reveals that adipocyte-derived IL-6 and leptin promote PLOD2 expression by activating the JAK/STAT3 and PI3K/AKT signaling pathways, thus promoting breast cancer metastasis.

     

Rad9 plays an important role in DNA mismatch repair through physical interaction with MLH1

Rad9 is conserved from yeast to humans and plays roles in DNA repair (homologous recombination repair, and base-pair excision repair) and cell cycle checkpoint controls. It has not previously been reported whether Rad9 is involved in DNA mismatch repair (MMR). In this study, we have demonstrated that both human and mouse Rad9 interacts physically with the MMR protein MLH1. Disruption of the interaction by a single-point mutation in Rad9 leads to significantly reduced MMR activity. This disruption does not affect S/M checkpoint control and the first round of G₂/M checkpoint control, nor does it alter cell sensitivity to UV light, gamma rays or hydroxyurea. Our data indicate that Rad9 is an important factor in MMR and carries out its MMR function specifically through interaction with MLH1.     

Evaluation of antimicrobial activity of certain Chinese plants used in folkloric medicine

Six selected plants, belonging to 3 families from Nanjing of China, were extracted with the solvent 95% (v/v) ethanol to yield 11 extracts. The extracts were evaluated for their effects on the growth of eight clinical bacteria, two fungi and one yeast using a modified agar diffusion method. The results showed that the majority of the extracts investigated showed greater activities against the Gram-positive bacteria than against the Gram-negative bacteria, the fungi and the yeast. The strongest antimicrobial activity was exhibited by the stem extracts of Mahonia fortunei against multiresistant Staphylococcus aureus strains, followed by the stem extracts of Mahonia bealei, while Bacillus thuringiensis was the most sensitive to all extracts.     

Oxytocin is expressed by both intrinsic sensory and secretomotor neurons in the enteric nervous system of guinea pig

Single- and double-immunostaining techniques were used systematically to study the distribution pattern and neurochemical density of oxytocin-immunoreactive (-ir) neurons in the digestive tract of the guinea pig. Oxytocin immunoreactivity was distributed widely in the guinea pig gastrointestinal tract; 3%, 13%, 17%, 15%, and 10% of ganglion neurons were immunoreactive for oxytocin in the myenteric plexuses of the gastric corpus, jejunum, ileum, proximal colon, and distal colon, respectively, and 36%, 40%, 52%, and 56% of ganglion neurons were immunoreactive for oxytocin in the submucosal plexuses of the jejunum, ileum, proximal colon, and distal colon, respectively. In the myenteric plexus, oxytocin was expressed exclusively in the intrinsic enteric afferent neurons, as identified by calbindin 28 K. In the submucosal plexuses, oxytocin was expressed in non-cholinergic secretomotor neurons, as identified by vasoactive intestinal polypeptide. Oxytocin-ir nerve fibers in the inner circular muscle layer possibly arose from the myenteric oxytocin-ir neurons, and oxytocin-ir nerve fibers in the mucosa possibly arose from both the myenteric and submucosal oxytocin-ir neurons. Thus, oxytocin in the digestive tract might be involved in gastrointestinal tract motility mainly via the regulation of the inner circular muscle and the balance of the absorption and secretion of water and electrolytes.     

AIDA Selectively Mediates Downregulation of Fat Synthesis Enzymes by ERAD to Retard Intestinal Fat Absorption and Prevent Obesity

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Short-term in vitro culture of purity and highly functional rat bone marrow-derived mast cells

Mast cells (MCs) are responsible for the innate immune response. Rat MCs are more suitable than mouse MCs as models of specific parasite infection processes and ovalbumin-induced asthma. Rat peritoneum-derived MCs and RBL-2H3 cells (an MC cell line) are widely used in disease studies. However, the application of rat bone marrow-derived MCs (BMMCs) are poorly documented in terms of the methodology of rat BMMC isolation. Here, we describe a relatively rapid, efficient, and simple method for the cultivation of rat BMMCs. As compared to previous protocols, rat BMMCs produced with the proposed protocol exhibited advantages in differentiation, proliferation, lifespan, and functionality, which should prove useful for studies of mucosal MC diseases in specific rat models.     

Improved Sp1 and Betaine Homocysteine-S-Methyltransferase Expression and Homocysteine Clearance Are Involved in the Effects of Zinc on Oxidative Stress in High-Fat-Diet-Pretreated Mice

Zinc plays a role in alleviating oxidative stress. However, the related mechanisms remain to be further elucidated. The present study was conducted to investigate whether the recovery of oxidative stress in high-fat-diet (HFD)-pretreated mice was affected by zinc. Male mice received either an HFD or a low-fat-diet (LFD) for 8 weeks. Then, the mice fed with HFD and LFD were both assigned to either a control diet (30 mg zinc, ZD) or a no-added zinc diet (NZD) for an additional 4 weeks. The results showed that after feeding with NZD for 4 weeks, the HFD-pretreated mice had the highest plasma glucose and insulin concentrations, while had the lowest CuZn-SOD and glutathione concentrations. Moreover, after feeding with NZD for 4 weeks, the HFD-pretreated mice had the highest hepatic ROS and homocysteine concentrations, while had the lowest glutathione and methionine concentrations. Furthermore, the HFD-pretreated mice fed with NZD for 4 weeks had the lowest gene and protein expression of betaine homocysteine-S-methyltransferase (BHMT), cystathionine β-synthase, and Sp1. The results suggested that zinc was critical for oxidative stress alleviation and homocysteine clearance in HFD-pretreated mice. It was further elucidated that improved Sp1 and BHMT expression are involved in the effects of zinc on oxidative stress.     

表油菜素内酯对月季切花保鲜作用的研究

本文初步探讨了表油菜素内酯（epiBR）对瓶插月季切花的保鲜作用。与对照（蒸馏水）和基本液（2％蔗糖＋500mgL-1柠檬酸＋250mgL-8-羟基喹啉＋25mgAgNO3）相比,经epiBR处理（基本液＋0．1mgL-1epiBR）的月季切花花枝坚挺,蓝变延迟,瓶插寿命延长1-1.5倍。测定有关生理指标表明,epiBR处理对月季切花瓶插花枝前期鲜重的增加及后期的保持有明显作用。并显著延缓花瓣和叶片质膜相对透性的增加,还能使瓶插前期花瓣还原糖含量增加。epiBR处理对花瓣蛋白质和叶片叶绿素含量变化无明显影响,而对花瓣花青素水平下降有轻微的促进作用。