Regulation of AKT phosphorylation by GSK3ß and PTEN to control chemoresistance in breast cancer.

BACKGROUND: Phosphorylated AKT is highly expressed or overexpressed in chemoresistant tumor samples. However, the precise molecular mechanism involved in AKT phosphorylation-related chemoresistance in breast cancer is still elusive. The present research was designed to estimate the effect of AKT phosphorylation on cell viability and chemoresistance in breast cancer. METHODS: We utilized MCF-7 and MDA-MB468 human breast cancer cell lines and developed multidrug-resistant MCF-7/MDR and cisplatin-resistant MDA-MB-468 cells. Immunofluorescence analysis and Western blotting were employed to test the level of glycogen synthase kinase 3 beta (GSK3ß), phosphorylated phosphatase and tension homologue (p-PTEN) and phosphorylated AKT (p-AKT) in MCF-7/MDR and MDA-MB468 cells. Xenograft assays in nude mice were performed with MCF-7/MDR cells to verify chemoresistance and the signaling pathway upstream of phosphatidylinositide 3-kinase (PI3K)/AKT. RESULTS: An increase in GSK3ß, p-PTEN and p-AKT expression was strongly induced in MCF-7/MDR and cisplatin-resistant MDA-MB-468 cells, and augmented GSK3ß phosphorylation and PTEN inactivation enhanced AKT signaling. The elevation in GSK3ß, p-PTEN and p-AKT was associated with cell viability based on a CCK-8 assay. The results of in vivo and in vitro assays indicated that GSK3ß knockdown with lentiviral shRNA (shRNA-GSK3ß) promoted apoptosis and suppressed the migration of cisplatin-resistant MCF-7/MDR cells, while these effects were reversed by activating p-AKT with the PTEN inhibitor bpV(pic). CONCLUSIONS: AKT phosphorylation mediated by GSK3ß and PTEN were correlated with cell viability, migration and apoptosis, which may promote chemoresistance in breast cancer. Furthermore, GSK3ß can regulate cell viability through the PTEN/PI3K/AKT signaling pathway and induce chemoresistance, serving as a valuable molecular strategy for breast cancer therapy.

Studies of the Efficacy of Low-Dose Apatinib Monotherapy as Third-Line Treatment in Patients with Metastatic Colorectal Cancer and Apatinib's Novel Anticancer Effect by Inhibiting Tumor-Derived Exosome Secretion.

Antiangiogenic therapy is an important treatment strategy for metastatic colorectal cancer (mCRC). We carried out a clinical study of low-dose apatinib (250 mg) monotherapy as a third-line treatment in patients with mCRC and assessed its efficacy and safety. It demonstrated that low-dose apatinib had comparable survival outcomes, significantly improved the patient quality of life, and caused tolerable adverse reactions. To further investigate the underlying mechanism of the effects of apatinib in CRC besides angiogenesis, we performed RNA-seq, and our results suggested that apatinib may have other potential antitumor mechanisms in CRC through multiple pathways, including exosomes secretion. In RKO and HCT116 cells, apatinib significantly reduced exosomes secretion by targeting multivesicular body (MVB) transport. Further studies have indicated that apatinib not only promoted the degradation of MVBs via the regulation of LAMP2 but also interfered with MVB transport by inhibiting Rab11 expression. Moreover, apatinib inhibited MVB membrane fusion by reducing SNAP23 and VAMP2 expression. In vivo, apatinib inhibited orthotopic murine colon cancer growth and metastasis and reduced the serum exosomes amount. This novel regulatory mechanism provides a new perspective for the antitumor effect of apatinib beyond angiogenesis inhibition.

Neuroprotective effect of l-serine against white matter demyelination by harnessing and modulating inflammation in mice.

Demyelination in white matter is the end product of numerous pathological processes. This study was designed to evaluate the neuroprotective effect of l-serine and the underlying mechanisms against the demyelinating injury of white matter. A model of focal demyelinating lesions (FDL) was established using the two-point stereotactic injection of 0.25% lysophosphatidylcholine (LPC, 10 µg per point) into the corpus callosum of mice. Mice were then intraperitoneally injected with one of three doses of l-serine (114, 342, or 1026 mg/kg) 2 h after FDL, and then twice daily for the next five days. Behavior tests and histological analysis were assessed for up to twenty-eight days post-FDL induction. Electron microscopy was used for ultrastructural investigation. In vitro, we applied primary co-cultures of microglia and oligodendrocytes for oxygen glucose deprivation (OGD). After establishing FDL, l-serine treatment: 1) improved spatial learning, memory and cognitive ability in mice, and relieved anxiety for 4 weeks post-FDL induction; 2) reduced abnormally dephosphorylated neurofilament proteins, increased myelin basic protein, and preserved anatomic myelinated axons; 3) inhibited microglia activation and reduced the release of inflammatory factors; 4) promoted recruitment and proliferation of oligodendrocyte progenitor cells, and the efficiency of subsequent remyelination on day twenty-eight post-FDL induction. In vitro experiments, showed that l-serine not only directly protected against oligodendrocytes from OGD damage, but also provided an indirect protective effect by regulating microglia. In our study, l-serine offered long-lasting behavioral and oligodendrocyte protection and promoted remyelination. Therefore, l-serine may be an effective clinical treatment aganist white matter injury.

A stable and easily reproducible model of focal white matter demyelination.

BACKGROUND: Demyelination is the end product of numerous pathological processes, and also is one of the main causes of neurological disability in Multiple sclerosis (MS). Research into the pathogenesis of MS is hampered by the conventional rodent models' inability to produce stable demyelination. NEW METHOD: Focal demyelinating lesions were stereotactically targeted to the corpus callosum with a two-point injection of lysophosphatidylcholine (LPC-2) in mice. Three groups were analyzed (n = 8, each) and water maze, sensorimotor test, and compound action potential were included in functional tests. Electron microscopy was used for morphological analyses while western blot and immunohistochemistry were included for molecular detection. RESULTS: Ten days after the LPC-2 injection, the expression of myelin basic protein (MBP) was reduced, while non-phosphorylated neurofilament (SMI-32) was increased. The amplitude of the N1 segment decreased and less well-defined myelin sheaths was found. Behavioral tests showed increased latency to escape and reduced time spent in target quadrant. Four weeks later, MBP expression still reduced, SMI-32 expression was increased, both spatial learning (D24-D27) and spatial memory (D28) were still significantly impaired in LPC-2 injection mice. COMPARISON WITH EXISTING METHOD(S): Compared with the classic single-point LPC-injection model, our studies showed that the two-point LPC-injection not only could induce demyelination in a short-term manner, but also could cause demyelination in a long-term manner with little remyelination in the mouse corpus callosum. CONCLUSIONS: We established a simple, reliable, and inexpensive model of demyelination in the corpus callosum in mice, with functional and morphological reproducibility, and good validity.

[Association mapping of schizophrenia loci on chromosome 1 by use of pooled DNA genomic screening in eastern Shandong peninsula].

OBJECTIVE: To find out association mapping of loci related to schizophrenia on chromosome 1 with microsatellite markers in DNA pooling samples from schizophrenic cases and normal controls in Shandong peninsula. METHODS: A total of 31 microsatellite markers on chromosome 1 spaced at approximately 10 cM were scanned to two separated DNA pooling samples consisting of 119 schizophrenic cases and 119 normal controls respectively. Statistic analysis was performed by Chi-square test method to compare the difference between the ratio of each allele between the two pooling samples. RESULTS: Significant statistic difference was found at D1S2878 between cases and controls, and P< 0.01 at this loci. CONCLUSION: D1S2878 locus on chromosome 1 associates with schizophrenia in Shandong peninsula. Fine mapping and searching for candidate genes are warranted in this region.

[Up-regulation of IFN-alpha on expression of MICA in the cervical carcinoma cell lines].

AIM: To investigate the effect of IFN-alpha on expression of MHC class I chain-related protein A (MICA) in the cervical carcinoma cell lines. METHODS: The cervical carcinoma cell lines (HeLa and Caski) were treated with IFN-alpha. The expression of MICA was measured by RT-PCR and by immunohistochemical staining. The cytotoxicity of human NK cells to the IFN-alpha treated cervical carcinoma cells was detected by MTT method. RESULTS: The mRNA and protein expression of MICA was up-regulated by IFN-alpha in HeLa and Caski cells in a time and dose-dependent manner. Compared to Caski cells which weakly expressed MICA, higher cytolytic activity of NK cells was found against HeLa cells, which expressed relatively higher level of MICA. After being treated with IFN-alpha for 3 d, the susceptibility of the two cervical carcinoma cells to NK cytolysis was increased significantly. CONCLUSION: IFN-alpha can up-regulate the MICA expression in the cervical carcinoma cell lines and thereby enhance the susceptibility to cytolysis of NK cells.

Expression of leptin receptors and response to leptin stimulation of human natural killer cell lines.

We previously reported that deficiency of leptin receptor (Ob-R(-/-), db/db) in mice led to impaired NK cell function. In the present paper, we, for the first time, found that human NK cell lines constitutively expressed leptin receptor (Ob-R), both long form Ob-R (Ob-R(L)) and short form Ob-R (Ob-R(S)), using immunohistochemical method, Western blotting, and RT-PCR assay. Interestingly, IL-2-dependent NK-92 cells proliferated without change in the presence or absence of leptin stimulation, but their cytotoxicity was dose-dependently responsible for leptin stimulation. The IL-2-independent YT cells were dose-dependently responsible for leptin stimulation to manifest rapid proliferation and strong cytotoxicity against tumor targets. In order to explain the mechanisms underlying the leptin function on NK cell lines, we examined the gene expression of cytokines (IL-2, IFNr), cytotoxic-associated molecules (perforin, FasL) and the activation of cytokine signal pathways (STAT1, STAT3). The results demonstrated that leptin activated the phosphorylation of STAT3 and then improved transcription of IL-2 and perforin genes. Our preliminary study indicates that leptin could affect NK cell function and may play an important role in innate immunity.