Recognition of Mycobacterium tuberculosis by macrophage Toll-like receptor and its role in autophagy.

BACKGROUND: The pathogen responsible for tuberculosis is called Mycobacterium tuberculosis. Its interaction with macrophages has a significant impact on the onset and progression of the disease. METHODS: The respiratory pathway allows Mycobacterium tuberculosis to enter the body's lungs where it battles immune cells before being infected latently or actively. In the progress of tuberculosis, Mycobacterium tuberculosis activates the body's immune system and creates inflammatory factors, which cause tissue inflammation to infiltrate and the creation of granulomas, which seriously harms the body. Toll-like receptors of macrophage can mediate host recognition of Mycobacterium tuberculosis, initiate immune responses, and participate in macrophage autophagy. New host-directed therapeutic approaches targeting autophagy for drug-resistant Mycobacterium tuberculosis have emerged, providing new ideas for the effective treatment of tuberculosis. CONCLUSIONS: In-depth understanding of the mechanisms by which macrophage autophagy interacts with intracellular Mycobacterium tuberculosis, as well as the study of potent and specific autophagy-regulating molecules, will lead to much-needed advances in drug discovery and vaccine design, which will improve the prevention and treatment of human tuberculosis.

INPP4B exerts a dual function in the stemness of colorectal cancer stem-like cells through regulating Sox2 and Nanog expression.

Inositol polyphosphate 4-phosphatase type II (INPP4B), a lipid phosphatase, was identified as a negative regulator of phosphatidylinositol 3-kinase (PI3K)/Akt signaling in several cancers. The expression and biological function of INPP4B in human colorectal cancer (CRC) are controversial, while the role and molecular mechanism of INPP4B in colorectal cancer stem-like cells (CR-CSLCs) remains unclear. Here, we observed that INPP4B expression was markedly decreased in primary non-metastatic CR-CSLCs and increased in highly metastatic CR-CSLCs compared with corresponding control non-CSLCs. INPP4B overexpression inhibited self-renewal, and chemoresistance of primary non-metastatic CR-CSLCs, but exerted the opposite roles in highly metastatic CR-CSLCs in vitro. Similarly, INPP4B knockdown had dual functions in the self-renewal and chemoresistance of different CR-CSLCs. In addition, we demonstrated that INPP4B overexpression suppressed the tumorigenicity of primary non-metastatic CR-CSLCs while induced the tumorigenicity of highly metastatic CR-CSLCs in nude mice. Furthermore, INPP4B was found to modulate the stemness of CR-CSLCs by regulating Sox2 and Nanog expression, which was dependent on PI3K/PTEN/Akt signaling. In conclusion, our results highlight an important role of INPP4B in the stemness of CR-CSLCs for the first time and emphasize INPP4B as a dual therapeutic target for suppressing primary cancer cell proliferation and for preventing metastasis in CRC patients.

Quercetin restrains TGF-ß1-induced epithelial-mesenchymal transition by inhibiting Twist1 and regulating E-cadherin expression.

Emerging evidence has indicated that transforming growth factor-beta 1 (TGF-ß1) induces the epithelial-mesenchymal transition (EMT) in cancer cells, thus promoting their motility and invasiveness. Quercetin, a member of the polyphenolic flavonoid family, has been reported to display anticancer activity against a broad range of cancer cell types. Indeed, numerous studies have shown the cancer preventive effects and molecular mechanisms of quercetin in vitro using diverse cell model systems. However, the potential effect of quercetin on EMT remains unclear. In this study, we identified a unique function of quercetin in inhibiting the EMT process induced by TGF-ß1. In particular, quercetin rescued the morphological changes and EMT-like phenotypes in TGF-ß1-activated SW480 cells, and this inhibition of TGF-ß1-induced EMT was mediated via the suppression of Twist1 expression. In addition, quercetin strongly suppressed TGF-ß1-induced invasion of SW480 cells. Thus, quercetin may be considered a novel therapeutic agent for the treatment of patients with refractory cancer and for the prevention of the metastatic cascade initiated by EMT.

Defensins: A novel weapon against Mycobacterium tuberculosis?

Tuberculosis (TB) is a serious airborne communicable disease caused by organisms of the Mycobacterium tuberculosis (Mtb) complex. Although the standard treatment antimicrobials, including isoniazid, rifampicin, pyrazinamide, and ethambutol, have made great progress in the treatment of TB, problems including the rising incidence of multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB), the severe toxicity and side effects of antimicrobials, and the low immunity of TB patients have become the bottlenecks of the current TB treatments. Therefore, both safe and effective new strategies to prevent and treat TB have become a top priority. As a subfamily of cationic antimicrobial peptides, defensins are rich in cysteine and play a vital role in resisting the invasion of microorganisms and regulating the immune response. Inspired by studies on the roles of defensins in host defence, we describe their research history and then review their structural features and antimicrobial mechanisms, specifically for fighting Mtb in detail. Finally, we discuss the clinical relevance, therapeutic potential, and potential challenges of defensins in anti-TB therapy. We further debate the possible solutions of the current application of defensins to provide new insights for eliminating Mtb.

MicroRNA-126 regulates the induction and function of CD4(+) Foxp3(+) regulatory T cells through PI3K/AKT pathway.

Recent evidence showed that limited activation of PI3K/Akt pathway was critical for induction and function sustainment of CD4(+) Foxp3(+) regulatory T cells (Tregs). However, the underlying mechanism remains largely unknown. In this study, we reported that miR-126 was expressed in mouse and human Tregs. Further study showed that silencing of miR-126 using miR-126 antisense oligonucleotides (ASO) could significantly reduce the induction of Tregs in vitro. Furthermore, miR-126 silencing could obviously reduce the expression of Foxp3 on Tregs, which was accompanied by decreased expression of CTLA-4 and GITR, as well as IL-10 and TGF-ß, and impair its suppressive function. Mechanistic evidence showed that silencing of miR-126 enhanced the expression of its target p85ß and subsequently altered the activation of PI3K/Akt pathway, which was ultimately responsible for reduced induction and suppressive function of Tregs. Finally, we further revealed that miR-126 silencing could impair the suppressive function of Tregs in vivo and endow effectively antitumour effect of CD8(+) T cells in adoptive cell transfer assay using a murine breast cancer model. Therefore, our study showed that miR-126 could act as fine-tuner in regulation of PI3K-Akt pathway transduction in the induction and sustained suppressive function of Tregs and provided a novel insight into the development of therapeutic strategies for promoting T-cell immunity by regulating Tregs through targeting specific miRNAs.

TLR9 signaling repressed tumor suppressor miR-7 expression through up-regulation of HuR in human lung cancer cells.

BACKGROUND: Our recent evidence showed that Toll like receptor 9 (TLR9) signaling could enhance the growth and metastatic potential of human lung cancer cells through repressing microRNA-7 (miR-7) expression. Human antigen R (HuR) has been involved in stabilizing multiple mRNAs in cellular biology. However, whether HuR also contributed to the altered expression of miR-7 in TLR9 signaling stimulated human lung cancer cells remains to be elucidated. METHODS: The expression of HuR in human lung cancer 95D cells treated with TLR9 agonist CpG Oligonucleotides (ODNs) was detected by Real-time PCR and Western blot assay. To explore the possible role of HuR on miR-7 expression, eukaryotic expression vector encoding HuR was transiently transfected into 95D cells and then the expression of miR-7 was detected by Real-time PCR assay. Moreover, RNA interference, western blot, Real-time PCR, MTT assay, BrdU labeling, invasion assay and scratch assay were employed to examine the disrupt effect of HuR on miR-7 expression in human lung cancer cells treated with CpG ODNs. Finally, inhibitors for PI3K, Akt or Erk respectively, and western blot were performed to explore the possible signaling pathway related to HuR expression in CpG ODNs treated human lung cancer cells. RESULTS: Our data showed that TLR9 agonist CpG ODNs could induce the expression of HuR in human lung cancer cells. Moreover, overexpression of HuR could reduce the expression of miR-7 in lung cancer cells. Notably, down-regulation of HuR using RNA interference restored miR-7 expression in CpG ODNs treated lung cancer cells, accompanied by enhanced growth and metastatic potential. Finally, CpG ODNs could induce HuR expression through Akt pathway. CONCLUSION: Our findings indicated that HuR could act as regulator in regulating TLR9 signaling associated biological effect in human lung cancer cells, which might be helpful for the understanding of the potential role of HuR in tumor biology.

Profiling of human leukocyte antigens in Eales disease and tuberculosis.

To analyze the association between Eales disease, histocompatibility leukocyte antigen alleles (HLA-A/B, HLA-DRB/DQB) and tuberculosis infection, and to explore susceptible genes and protective genes associated with Eales disease and tuberculosis infection in a population of Han nationals from Zunyi City in Guizhou Province, China. The subjects were analyzed by a case-control study consisting of three groups--Eales disease group (47 cases), pulmonary tuberculosis group (36 cases) and normal control group (100 cases). The Eales disease group was divided into four parts. Part one consisted of 12 patients who had suffered from pulmonary tuberculosis. Part two consisted of 27 patients who had not suffered from pulmonary tuberculosis. Parts three and four consisted of 27 patients with a positive purified protein derivative test and 12 patients with a negative test, respectively. DNA samples from 47 patients with Eales disease, 36 patients with pulmonary tuberculosis and 100 healthy people were detected by polymerase chain reaction with sequence-specific primers. The 59 HLA-A/B and HLA-DRB/DQB alleles from Eales disease were compared with those from tuberculosis and normal control, and a correlativity test of common susceptible genes was performed to analyze the potential relationship between Eales disease and pulmonary tuberculosis. The frequency distribution of HLA-A*02 alleles (OR 9.719, OR 95 % CI 4.377-21.580, P = 0.000) and HLA-B*07 (OR 11.605, OR 95 % CI 2.397-56.191, P = 0.001) in the Eales disease group was higher than in the normal control group, but the HLA-A*11 alleles (OR 0.495, OR 95 % CI 0.245-1.000, P = 0.048) were lower than in the normal control group, showing a significant difference. Compared with parts two and four, the frequency distribution of HLA-A*02, HLA-A*11 and HLA-B*07 alleles in parts one and three showed no significant difference (P > 0.05). HLA-A*A02, HLA-A*24, HLA-B*07 and HLA-DRB*16 alleles between the Eales disease, pulmonary tuberculosis and normal control group showed statistical significance (P < 0.05). HLA-A*24 alleles in the pulmonary tuberculosis group were lower than the Eales disease group (χ(2) 7.289, P = 0.007), but HLA-A*02 alleles showed no significant difference (P > 0.05) between the two groups. The results show that HLA-A*02 and HLA-B*07 may be genetic predisposing genes, but HLA-A*11 alleles may be protective genes of Eales disease, the HLA-A*02 allele may be a common susceptible gene of Eales disease and pulmonary tuberculosis. HLA-A*11 and HLA-A24 alleles are protective genes of Eales disease and pulmonary tuberculosis, respectively. In summary, the frequency distribution of susceptible genes of Eales disease and pulmonary tuberculosis in a population of Han nationals from Zunyi City in Guizhou Province, China showed no significant difference.

MicroRNA-140-5p regulates the proliferation, apoptosis and inflammation of RA FLSs by repressing STAT3.

Ectopic expression of microRNA (miRNA) in rheumatoid arthritis (RA) fibroblast-like synoviocyte (RA FLS) is associated with the development of rheumatoid arthritis. The present study aimed to evaluate the effects of miRNA-140-5p (miR-140) on the properties of RA FLSs. It was found that miR-140 expression was decreased in 33 RA patients and extracted RA FLS samples, when compared to the corresponding healthy controls. Abnormally increased miR-140 expression in RA FLSs attenuated cell proliferation and increased cell apoptosis. Additionally, reduced pro-inflammatory cytokine production was observed in RA FLSs transfected with a miR-140 precursor. Furthermore, the 3'-UTR of the signal transducer and activator of transcription (STAT) 3 gene was identified as a target of miR-140. Notably, restoration of STAT3 expression rescued the regulatory effect of miR-140 on the proliferation, apoptosis and inflammatory cytokine production of RA FLSs. Therefore, the current findings indicated that miR-140 is a crucial modulator of both proliferation and apoptosis, shedding light on the etiology behind RA FLS viability, which is modulated by an interplay between miR-140 and STAT3 in the context of RA.

[The change of CD4+ CD25high CCR6+ regulatory T cells in breast cancer patients].

OBJECTIVE: To detect the proportion of CD4+ CD25high CCR6+ regulatory T cells in peripheral blood mononuclear cells and tumor infiltration lymphocytes from breast cancer patients and explore its significance. METHODS: Lymphocytes isolated from blood and tumor mass of breast cancer patients were analyzed for the proportion of CD4+ CD25high CCR6+ regulatory T cells by flow cytometry. The expression of Foxp3 on CD4+ CD25high CCR6+ regulatory T cells, as well as CD45RO, CD44 and CD62L, were also analyzed. The effects of CD4+ CD25high CCR6+ regulatory T cells on the proliferation of CD4+ CD25- T cells also were detected by 3H-incorporation assay. RESULTS: Compared to the control, increased proportion of CD4+ CD25high CCR6+ regulatory T cells was observed in PBMCs and TILs from breast cancer patients. Moreover, CD4+ CD25high CCR6+ regulatory T cells, expressing high level of Foxp3, displayed effector memory phenotype determined by high level expression of CD45RO, CD44 and low level of CD62L. In addition, CD4+ CD25high CCR6+ regulatory T cells could inhibit the proliferation of CD4+ CD25- T cells in vitro. CONCLUSION: The enrichment of CD4+ CD25high CCR6+ regulatory T cells in tumor mass in breast cancer patients, which might be close related to long term immunoescape of tumor.

Mycobacterium tuberculosis Heat-Shock Protein 16.3 Induces Macrophage M2 Polarization Through CCRL2/CX3CR1.

Mycobacterium tuberculosis, the pathogen of tuberculosis (TB), can survive in host macrophages and induce macrophages to M2 phenotype might result in latent MTB infection. During the latent phase, the expression of MTB heat-shock protein 16.3 (Hsp16.3) is markedly increased among most of bacterial proteins, but the role of Hsp16.3 in macrophage M2 polarization is not clear. In this work, we found that macrophages incubated with 100 ng/ml MTB Hsp16.3 increased the production of Arg-1, IL-10, TGF-beta, and CD206. These results showed that MTB Hsp16.3 may induce macrophage M2 phenotype. And the interaction of Hsp16.3 with macrophages was found to depend on chemokine receptors CCRL2 and CX3CR1. Additionally, we used overexpression and silencing techniques to further verify the effect of CCRL2 and CX3CR1 on MTB Hsp16.3-induced M2 polarization macrophages. Furthermore, we explored the downstream signaling molecules of CCRL2 and CX3CR1 and we found MTB Hsp16.3 altered the signal transduction of the AKT/ERK/p38-MAPK. Taken together, this study provides evidence that MTB Hsp16.3 promotes macrophages to M2 phenotype and explores its underlying mechanism.

CXCR4/SDF-1 pathway is crucial for TLR9 agonist enhanced metastasis of human lung cancer cell.

Accumulating data suggested that CXCR4/SDF-1 pathway may play an important role in the metastasis of tumor. We previously demonstrated that CpG ODN could enhance the metastasis of human lung cancer cell via TLR9. Here we further evaluated the possible role of CXCR4/SDF-1 pathway in the enhanced metastasis of human lung cancer 95D cells induced by CpG ODN. Our data showed down-regulation of CXCR4 expression using siRNA against CXCR4 could significantly reduce the enhanced metastasis of 95D cells induced by CpG ODN both in vitro and in vivo. These results suggested that TLR9 agonist might promote the metastasis of human lung cancer cells via CXCR4/SDF-1 pathway.

The PEAK1-PPP1R12B axis inhibits tumor growth and metastasis by regulating Grb2/PI3K/Akt signalling in colorectal cancer.

Pseudopodium enriched atypical kinase 1 (PEAK1), a novel non-receptor tyrosine kinase, was recently implicated in cancer pathogenesis. However, its functional role in colorectal cancer (CRC) is not well known. Herein, we demonstrated that PEAK1 was frequently downregulated in CRC and significantly associated with tumor size, differentiation status, metastasis, and clinical stage. PEAK1 overexpression suppressed CRC cell growth, invasion, and metastasis in vitro and in vivo, whereas knockout had the opposite effects. Further evaluation revealed that PEAK1 expression was positively correlated with protein phosphatase 1 regulatory subunit 12B (PPP1R12B) in CRC cell lines and clinical tissues, and this protein was found to suppress activation of the Grb2/PI3K/Akt pathway. Moreover, PPP1R12B knockdown markedly abrogated PEAK1-mediated tumor suppressive effects, whereas its upregulation recapitulated the effects of PEAK1 knockout on cell behaviours and the activation of signalling. Mechanistically, PI3K and Akt inhibitors reversed impaired the effect of PEAK1 function on cell proliferation, migration, and invasion. Our results provide compelling evidence that the PEAK1-PPP1R12B axis inhibits colorectal tumorigenesis and metastasis through deactivation of the Grb2/PI3K/Akt pathway, which might provide a novel therapeutic strategy for CRC treatment.

MicroRNA-21: A promising biomarker for the prognosis and diagnosis of non-small cell lung cancer.

Non-small cell lung cancer (NSCLC) is the most common subtype of lung cancer worldwide. The high mortality rate of NSCLC is due to a limited number of diagnosis being made at an early stage of disease. Therefore, the development of a novel biological marker for the diagnosis and prognosis prediction of NSCLC remains urgent. Current literature shows that microRNA-21 (miRNA-21/miR-21), as an oncogenic miRNA, is involved in the growth, metastasis and apoptosis of NSCLC cells through its control of various target molecules and signaling pathways. Notably, a growing body of evidence further shows that miR-21 is closely associated with the prognosis prediction, recurrence and diagnosis of cancer patients, indicating that miR-21 may be a novel promising biomarker for the diagnosis and prognosis prediction of NSCLC. The present review aimed to provide a summary of recent findings on the associated progression toward finding a novel biomarker for NSCLC.

Elevated Gab2 induces tumor growth and angiogenesis in colorectal cancer through upregulating VEGF levels.

BACKGROUND: Grb2-associated binder 2 (Gab2) is a scaffolding protein that serves as a critical signaling amplifier downstream of tyrosine kinase receptors. Our previous study has shown that Gab2 induces epithelial-to-mesenchymal transition (EMT) and promotes metastasis in colorectal cancer (CRC). However, the role of Gab2 in CRC growth and angiogenesis remains unclear. METHODS: The expression of vascular endothelial growth factor (VEGF) in different colorectal tissues was detected by immunohistochemistry and qRT-PCR to evaluate its correlation with Gab2. Lentiviral vectors bearing Gab2 gene and its small interfering RNAs were constructed and transfected into CRC cell lines. The effects of Gab2 on the cell proliferation in vitro and tumorigenesis in vivo, were examined via CCK­8 assay, colony formation assay as well as tumorigenicity assay respectively. Moreover, to assess its potential role in tumor growth and angiogenesis, the expression of Ki67, CD34 and vascular endothelial growth factor receptor-2 (VEGFR2) were detected by immunohistochemistry in CRC cells tumors. Finally, we evaluated the impact of Gab2 on the expression of c-Myc and VEGF, and the probable effect of mechanistic targeted extracellular signal-regulated kinase (ERK) pathway in suppressing tumor growth and angiogenesis. RESULTS: Up-regulation of Gab2 expression was found to be positively correlated with VEGF in CRC tissues. Exogenous expression of Gab2 obviously promoted, whereas silencing of Gab2 inhibited, proliferation and clone formation of human CRC cells in vitro. Of note, Gab2 enhanced tumorigenesis and tumor growth in mouse xenografts with high Ki67 expression, and led to an increased vessel density with strong CD34 and VEGFR2 activity. In addition, elevated Gab2 expression obviously up-regulated the expression of VEGF, and stimulated the activation of its downstream genes, ERK1/2 and c-Myc in CRC cells. Instead, down-regulated Gab2 expression significantly reduced the levels of VEGF, and inhibited the transduction of ERK/c-Myc pathway. Finally, we revealed that mechanistic target of mitogen-activated protein kinase (MEK) could attenuate Gab2-induced tumor growth and angiogenesis via altering VEGF and c-Myc levels. CONCLUSIONS: The results from our study suggest that Gab2 promotes intestinal tumor growth and angiogenesis through upregulation of VEGF expression mediated by the MEK/ERK/c-Myc pathway.

Gab2 facilitates epithelial-to-mesenchymal transition via the MEK/ERK/MMP signaling in colorectal cancer.

BACKGROUND: Grb2-associated binder 2 (Gab2), a scaffolding adaptor protein, has recently been implicated in cancer progression. However, the role of Gab2 in the progression and metastasis of colorectal cancer (CRC) remains unclear. METHODS: Gab2 expression was assessed in CRC patient specimens as well as in CRC cell lines. Recombinant lentivirus vector containing Gab2 gene and its small interfering RNAs were constructed and introduced into CRC cells. Cell migration and invasion ability were evaluated by transwell assays in vitro, and in vivo metastasis was performed on nude mice model. Moreover, the expression of Gab2 and epithelial-to-mesenchymal transition (EMT)-associated proteins (E-cadherin and vimentin) were assessed by western blot and qRT-PCR in CRC cells to evaluate the correlation between Gab2 and EMT. Finally, we evaluated the impact of Gab2 on the activation of its downstream signaling effectors, and furthermore the effects of these pathways on Gab2 induced-EMT were also detected. RESULTS: We confirmed that increased Gab2 expression correlated with higher tumor node metastasis stage and highly invasive CRC cell lines. Ectopic expression of Gab2 promoted metastasis of CRC cells, whereas silencing of Gab2 resulted in inhibited metastasis both in vitro and in vivo. Overexpression of Gab2 in CRC cells induced EMT, whereas knockdown of Gab2 had the opposite effect. Furthermore, upregulation of Gab2 expression obviously stimulated the activation of extracellular signal-regulated kinase-1/2 (ERK1/2), and increased the expression of matrix metalloproteinase-7 (MMP7) and matrix metalloproteinase-9 (MMP9) in CRC cells. Conversely, downregulation of Gab2 expression significantly decreased the activation of ERK1/2, and inhibited MMP7 and MMP9 expression. U0126, an inhibitor of mitogen-activated protein kinase (MEK), can reverse the effects of Gab2 on EMT. CONCLUSIONS: Our work highlights that Gab2 induces EMT through the MEK/ERK/MMP pathway, which in turn promotes intestinal tumor metastasis.

Gab2 is a novel prognostic factor for colorectal cancer patients.

Gab2 (Grb2-associated binder 2), a member of the DOS/Gab family of scaffolding adapters, serves as a critical signal amplifier downstream of various growth factor receptors. Recent studies have identified that Gab2 is overexpressed in several cancer types and that increased Gab2 expression promotes cell proliferation, cell transformation, and tumor progression. Here, we show for the first time that Gab2 protein is overexpressed in clinical colorectal cancer (CRC) specimens. Elevated mRNA (P=0.014) expression and protein (P=0.003) expression of Gab2 were found in most CRC tissues compared with the matched adjacent non-tumor tissues using real-time quantitative reverse transcription PCR (qRT-PCR) and western blotting, respectively. Immunohistochemical analyses showed that Gab2 protein was upregulated in CRC tissues relative to adjacent normal tissues (P<0.001), and this overexpression was significantly correlated with lymph node metastasis (P=0.007), distant metastasis (P<0.001) and TNM stage (P=0.002). According to Kaplan-Meier model, CRC patients with Gab2-positive had a significantly poorer prognosis compared to those with Gab2-negative (P=0.007). Multivariate analysis suggested that the positive expression of Gab2 protein was an independent prognostic factor for CRC patients. In conclusion, our data demonstrated that Gab2 expression may play an important role in the progression of CRC, and underscored that Gab2 has the potential value as a prognostic predictor for CRC patients.

Structure and function of Gab2 and its role in cancer (Review).

The docking proteins of the Grb-associated binder (Gab) family transduce cellular signals between receptors and intracellular downstream effectors, and provide a platform for protein­protein interactions. Gab2, a key member of the Gab family of proteins, is involved in the amplification and integration of signal transduction, evoked by a variety of extracellular stimuli, including growth factors, cytokines and antigen receptors. Gab2 protein lacks intrinsic catalytic activity; however, when phosphorylated by protein­tyrosine kinases (PTKs), Gab2 recruits several Src homology­2 (SH2) domain­containing proteins, including the SH2­containing protein tyrosine phosphatase 2 (SHP2), the p85 subunit of phosphoinositide­3 kinase (PI3K), phospholipase C­Î³ (PLCγ)1, Crk, and GC­GAP. Through these interactions, the Gab2 protein triggers various downstream signal effectors, including SHP2/rat sarcoma viral oncogene/RAF/mitogen­activated protein kinase kinase/extracellular signal­regulated kinase and PI3K/AKT, involved in cell growth, differentiation, migration and apoptosis. It has been previously reported that aberrant Gab2 and/or Gab2 signaling is closely associated with human tumorigenesis, particularly in breast cancer, leukemia and melanoma. The present review aimed to focus on the structure and effector function of Gab2, its role in cancer and its potential for use as an effective therapeutic target.

[Prokaryotic expression and function detection of Mycobacterium tuberculosis Hsp16.3].

OBJECTIVE: To construct a prokaryotic expression vector of Mycobacterium tuberculosis (MTB) small heat shock protein Hsp16.3, express and purify the fusion protein of His-Hsp16.3, and identify its function. METHODS: Hsp16.3 gene was amplified from H37Rv DNA by PCR, and then cloned into prokaryotic expression vector Pet28a. The positive recombinant plasmid Pet28a-Hsp16.3 was selected and identified by double enzyme digestion and sequencing. Then the recombinant plasmid of correct sequence was transformed into E.coli BL21 (DE3), and induced by IPTG. The expressed recombinant protein was analyzed by SDS-PAGE and Western blotting; the fusion protein was purified by Hislink spin protein purification system, and then detected for its concentration; real-time quantitative PCR (qRT-PCR) was used to determine the expressions of IL-10 and IFN-γ in mouse peritoneal macrophages treated by the purified fusion protein of different concentrations. Meanwhile, the blank control group and positive control group were set up and compared. RESULTS: Double enzyme digestion and sequencing showed that the recombinant plasmid Pet28a-Hsp16.3 was successfully constructed, and SDS-PAGE and Western blotting revealed that the fusion protein was expressed in E.coli BL21(DE3). Moreover, qRT-PCR showed that the purified fusion protein when added to the mouse peritoneal macrophage cells could significantly promote the produce of IFN-γ and restrain the expression of IL-10. CONCLUSION: MTB Hsp16.3 was successfully cloned, expressed and purified. His-Hsp16.3 could significantly promote the produce of IFN-γ and restrain the expression of IL-10.

[Over-expressed microRNA-7 inhibits the growth of human lung cancer cells via suppressing CGGBP1 expression].

OBJECTIVE: To investigate the effect of microRNA-7 (miR-7) over-expression on the growth of human lung cancer cells in vivo and in vitro and explore its possible mechanism. METHODS: The eukaryotic expression vector of pcDNA3.1 encoding miR-7 (p-miR-7) was transiently transfected into human lung cancer 95D cells in vitro. The proliferation of cells was detected by MTT assay and colony formation assay. Moreover, the expressions of nuclear antigen Ki-67 and CGG binding protein 1 (CGGBP1) were detected by immunofluorescence assay. Human lung cancer model in nude mice was established. Next, p-miR-7 vector was directly injected into local tumor tissue. Then, tumor size was measured and the survival time of mice was observed. The expression level of miR-7 in the tumor tissue was determined by real-time PCR. Finally, the expressions of Ki-67 and CGGBP1 were detected by immunohistochemistry. RESULTS: Over-expression of miR-7 could significantly inhibit the growth of 95D cells in vitro (P<0.05), accompanied by the remarkably reduced expressions of Ki-67 and CGGBP1 (P<0.05). Moreover, compared with those in control group, the expression level of miR-7 increased significantly in p-miR-7 injected group (P<0.05). Meanwhile, the growth of tumors in injected group was slower than in the control group. Consistently, the survival time of mice was dramatically prolonged in p-miR-7 injected group (P<0.05). The expression levels of Ki-67 and CGGBP1 also remarkably decreased in tumor tissue (P<0.05). CONCLUSION: Over-expression of miR-7 could significantly inhibit the growth of human lung cancer cells in vivo and in vitro, which might be related to the down-regulated expression of tumor growth-associated protein CGGBP1.

[Preparation of polyclonal antibody for heat shock protein 16.3].

OBJECTIVE: To induce the prokaryotic expression of His-heat shock protein 16.3 (Hsp16.3) and prepare its polyclonal antibody. METHODS: DNA primers were designed and synthesized, and Hsp16.3 cDNA was amplified from Mycobacterium tuberculosis H37Rv by PCR. Thereafter, the recombinant vector pET28a-Hsp16.3 was constructed, cloned and induced to express. The His-Hsp16.3 protein was purified using a Ni-NTA column. After identification by SDS-PAGE, the purified protein was used to immunize the New Zealand white rabbits to prepare the polyclonal antibody. The titer and biological activity of the polyclonal antibody were analyzed by ELISA and Western blotting, respectively. RESULTS: The prokaryotic expression vector pET28a-Hsp16.3 was constructed and expressed well in E.coil BL21(DE3). SDS-PAGE showed that the relative molecular mass was about 20 000. The titer of the polyclonal antibody reached 1:800. The purified antibody was proved to have a good specificity. CONCLUSION: The His-Hsp16.3 has been cloned, expressed and purified successfully. Polyclonal antibody of His-Hsp16.3 protein has been obtained as well.