[Show abstract][Hide abstract]ABSTRACT: Osteoarthritis (OA) is becoming a major public health problem in China, especially considering the increase in average life expectancy of the population. Thus, enhanced understanding of the molecular changes associated with OA is urgently needed to develop more effective strategies for the diagnosis and treatment of this debilitating disease. LncRNAs play an important role in the processes of bone and cartilage development. Maternally expressed gene 3 (MEG3) is a maternally expressed lncRNA and may function as a tumor suppressor by inhibiting angiogenesis. OA is closely associated with angiogenesis and the inhibition of angiogenesis presents a novel therapeutic approach to reduce inflammation and pain in OA. In this study, we detected the mRNA expression of MEG3 and VEGF in articular cartilage samples from 20 OA patients and 10 healthy volunteers by real-time RT-PCR. VEGF protein is detected by ELISA in cartilage samples. The results show that human MEG3 is significantly downregulated in OA patients compared to normal cartilage samples. However, higher levels of VEGF mRNA and protein are found in OA compared to the control. Moreover, MEG3 levels are inversely associated with VEGF levels, suggesting that MEG3 may be involved in OA development through the regulation of angiogenesis.
[Show abstract][Hide abstract]ABSTRACT: Autophagy plays an important role in prostate cancer development. It promotes tumor cell survival and was found to be associated with androgen pathway. In the present study, we found that GABA(A) receptor-associated protein like 1 (Gabarapl1), a ubiquitin-like modifier, participates in the regulation of autophagy. Gabarapl1 is transcriptionally regulated by androgen receptor (AR) and has a repressive role in autophagy. Androgen deprivation downregulates Gabarapl1 in an AR dependent manner, resulting in the increase of autophagy flux. Elevated Gabarapl1 also represses the proliferation of prostate cancer cells. In summary, our study provides evidence to show that Gabarapl1 is a mediator involved in androgen-regulated autophagy process.
[Show abstract][Hide abstract]ABSTRACT: Metastasis is the primary cause of prostate cancer (CaP)-related death. We investigate the molecular, pathologic and clinical outcome associations of EphA6 expression and CaP metastasis. The expression profiling of Eph receptors (Ephs) and their ephrin ligands was performed in parental and metastatic CaP cell lines. Among Ephs and ephrins, only EphA6 is consistently overexpressed in metastatic CaP cells. Metastatic potential of EphA6 is assessed by RNAi in a CaP spontaneous metastasis mouse model. EphA6 knock-down in human PC-3M cells causes decreased invasion in vitro and reduced lung and lymph node metastasis in vivo. In addition, knock-down of EphA6 decreases tube formation in vitro and angiogenesis in vivo. EphA6 mRNA expression is higher in 112 CaP tumor samples compared with benign tissues from 58 benign prostate hyperplasia patients. Positive correlation was identified between EphA6 expression and vascular invasion, neural invasion, PSA level, and TNM staging in CaP cases. Further, genome-wide gene expression analysis in EphA6 knock-down cells identified a panel of differentially regulated genes including PIK3IPA, AKT1, and EIF5A2, which could contribute to EphA6-regulated cancer progression. These findings identify EphA6 as a potentially novel metastasis gene which positively correlates with CaP progression. EphA6 may be a therapeutic target in metastatic CaP.
[Show abstract][Hide abstract]ABSTRACT: Metastatic melanoma, the primary cause of skin cancer-related death, warrants new diagnostic and therapeutic approaches that target the regulatory machinery at molecular level. The heterogeneity and complexity of melanoma result in the difficulty to find biomarkers and targets for early detection and treatment. Here, we investigated metastasis-associated proteins by comparing the proteomic profiles of primary cutaneous melanomas to their matched lymph node metastases, which minimizes heterogeneity among samples from different patients. Results of two-dimensional gel electrophoresis (2-DE) followed by proteomic analysis revealed eight differentially expressed proteins. Among them, seven proteins (α-enolase, cofilin-1, LDH, m-β-actin, Nm23, GRP78, and MDA-9) showed increased and one (annexin A2) showed decreased expression in metastatic lymph node tissues than in primary melanomas. MDA-9 and GRP78 were the most highly expressed proteins in lymph node metastases, which was validated by immunohistochemical staining. Moreover, exosomes from serum samples of metastatic melanoma patients contained higher levels of MDA-9 and GRP78 than those of patients without metastases, indicating the potential of MDA-9 and GRP78 to be biomarkers for early detection of metastasis. Further, small interfering RNA (siRNA)-mediated knockdown confirmed a functional role for MDA-9 and GRP78 to promote cell invasion in the A375 cells. Finally, we showed that GRP78 co-localized with MDA-9 in 293T cells. Taken together, our findings support MDA-9, co-expressed with GRP78, as a melanoma protein associated with lymph node metastasis. Investigating how MDA-9 and GRP78 interact to contribute to melanoma metastasis and disease progression could reveal new potential avenues of targeted therapy and/or useful biomarkers for diagnosis and prognosis.
[Show abstract][Hide abstract]ABSTRACT: Chemotaxis is controlled by interactions between receptors, Rho-family GTPases, phosphatidylinositol 3-kinases, and cytoskeleton remodeling proteins. We investigated how the metastasis suppressor, SSeCKS, attenuates chemotaxis. Chemotaxis activity inversely correlated with SSeCKS levels in mouse embryo fibroblasts (MEF), DU145 and MDA-MB-231 cancer cells. SSeCKS loss induced chemotactic velocity and linear directionality, correlating with replacement of leading edge lamellipodia with fascin-enriched filopodia-like extensions, the formation of thickened longitudinal F-actin stress fibers reaching to filopodial tips, relative enrichments at the leading edge of phosphatidylinositol (3,4,5)P3 (PIP3), Akt, PKC-ζ, Cdc42-GTP and active Src (SrcpoY416), and a loss of Rac1. Leading edge lamellipodia and chemotaxis inhibition in SSeCKS-null MEF could be restored by full-length SSeCKS or SSeCKS deleted of its Src-binding domain (ΔSrc), but not by SSeCKS deleted of its three MARCKS (myristylated alanine-rich C kinase substrate) polybasic domains (ΔPBD), which bind PIP2 and PIP3. The enrichment of activated Cdc42 in SSeCKS-null leading edge filopodia correlated with recruitment of the Cdc42-specific guanine nucleotide exchange factor, Frabin, likely recruited via multiple PIP2/3-binding domains. Frabin knockdown in SSeCKS-null MEF restores leading edge lamellipodia and chemotaxis inhibition. However, SSeCKS failed to co-immunoprecipitate with Rac1, Cdc42 or Frabin. Consistent with the notion that chemotaxis is controlled by SSeCKS-PIP (vs. -Src) scaffolding activity, constitutively-active phosphatidylinositol 3-kinase could override the ability of the Src inhibitor, SKI-606, to suppress chemotaxis and filopodial enrichment of Frabin in SSeCKS-null MEF. Our data suggest a role for SSeCKS in controlling Rac1 vs. Cdc42-induced cellular dynamics at the leading chemotactic edge through the scaffolding of phospholipids and signal mediators, and through the reorganization of the actin cytoskeleton controlling directional movement.
[Show abstract][Hide abstract]ABSTRACT: Activation of the PI3K/AKT signal pathway is a known driving force for the progression to castration-recurrent prostate cancer (CR-CaP), which constitutes the major lethal phenotype of CaP. Here, we identify using a genomic shRNA screen the PI3K/AKT-inactivating downstream target, FOXO4, as a potential CaP metastasis suppressor. FOXO4 protein levels inversely correlate with the invasive potential of a panel of human CaP cell lines, with decreased mRNA levels correlating with increased incidence of clinical metastasis. Knockdown (KD) of FOXO4 in human LNCaP cells causes increased invasion in vitro and lymph node (LN) metastasis in vivo without affecting indices of proliferation or apoptosis. Increased Matrigel invasiveness was found by KD of FOXO1 but not FOXO3. Comparison of differentially expressed genes affected by FOXO4-KD in LNCaP cells in culture, in primary tumors and in LN metastases identified a panel of upregulated genes, including PIP, CAMK2N1, PLA2G16 and PGC, which, if knocked down by siRNA, could decrease the increased invasiveness associated with FOXO4 deficiency. Although only some of these genes encode FOXO promoter binding sites, they are all RUNX2-inducible, and RUNX2 binding to the PIP promoter is increased in FOXO4-KD cells. Indeed, the forced expression of FOXO4 reversed the increased invasiveness of LNCaP/shFOXO4 cells; the forced expression of FOXO4 did not alter RUNX2 protein levels, yet it decreased RUNX2 binding to the PIP promoter, resulting in PIP downregulation. Finally, there was a correlation between FOXO4, but not FOXO1 or FOXO3, downregulation and decreased metastasis-free survival in human CaP patients. Our data strongly suggest that increased PI3K/AKT-mediated metastatic invasiveness in CaP is associated with FOXO4 loss, and that mechanisms to induce FOXO4 re-expression might suppress CaP metastatic aggressiveness.
[Show abstract][Hide abstract]ABSTRACT: A multiplex snapback primer system was developed for the simultaneous detection of JAK2 V617F and MPL W515L/K mutations in Philadelphia chromosome- (Ph-) negative myeloproliferative neoplasms (MPNs). The multiplex system comprises two snapback versus limiting primer sets for JAK2 and MPL mutation enrichment and detection, respectively. Linear-After exponential (LATE) PCR strategy was employed for the primer design to maximize the amplification efficiency of the system. Low ionic strength buffer and rapid PCR protocol allowed for selective amplification of the mutant alleles. Amplification products were analyzed by melting curve analysis for mutation identification. The multiplex system archived 0.1% mutation load sensitivity and <5% coefficient of variation inter-/intra-assay reproducibility. 120 clinical samples were tested by the multiplex snapback primer assay, and verified with amplification refractory system (ARMS), quantitative PCR (qPCR) and Sanger sequencing method. The multiplex system, with a favored versatility, provided the molecular diagnosis of Ph-negative MPNs with a suitable implement and simplified the genetic test process.
[Show abstract][Hide abstract]ABSTRACT: Type 2 diabetes mellitus (T2DM) is a major public health problem in China. Diagnostic markers are urgently needed to identify individuals at risk of developing T2DM and encourage them to adapt to a healthier life style. Circulating miRNAs present important sources of noninvasive biomarkers of various diseases. Recently, a novel plasma microRNA signature was identified in T2DM. Here, we evaluated the T2DM-related miRNA signature in plasma of three study groups: normal (fasting glucose (FG), 4.8-5.2 mmol/L), T2DM-susceptible (FG, 6.1-6.9 mmol/L), and T2DM individuals (FG, ≥7.0 mmol/L) and tested the feasibility of using circulating miRNAs to identify individuals at risk of developing T2DM. Among the 5 miRNAs included in the signature, miR-29b and miR-28-3p are not detectable. miR-15a and miR-223 have comparable expression levels among three groups. Notably, miR-126 is the only miRNA that showed significantly reduced expression in susceptible individuals and T2DM patients compared to normal individuals, suggesting that miR-126 in circulation may serve as a potential biomarker for early identification of susceptible individuals to T2DM.
[Show abstract][Hide abstract]ABSTRACT: Recurrence of prostate cancer (CaP) after androgen-deprivation therapy continues to have the greatest impact on patient survival. Castration-recurrent (CR)-CaP is likely driven by the activation of androgen receptor (AR) through multiple mechanisms including induction of AR coregulators, AR mutants or splice variants, and AR posttranslational modification such as phosphorylation by Src-family and Ack1 tyrosine kinases. Here, we address whether Src is required for the CR growth of human CWR22 CaP xenografts. The shRNA-mediated Src knockdown or treatment with the Src inhibitors, dasatinib or KXO1, reduced CaP recurrence over controls and increased time-to-recurrence following castration. Moreover, CR-CaP [Src-shRNA] tumors that recurred had similar Src protein and activation levels as those of parental cells, strengthening the notion that Src activity is required for progression to CR-CaP. In contrast, the ability of dasatinib or KXO1 to inhibit Src kinase activity in vitro did not correlate with their ability to inhibit serum-driven in vitro proliferation of CR and androgen-dependent stable cell lines derived from CWR22 tumors (CWR22Rv1 and CWR22PC, respectively), suggesting that the in vitro proliferation of these CaP lines is Src independent. Taken together, these findings strongly suggest that Src is a potent and specific therapeutic target for CR-CaP progression.
[Show abstract][Hide abstract]ABSTRACT: Metastatic melanoma, the primary cause of skin cancer-related death, warrants new therapeutic approaches that target the regulatory machinery at molecular level. While long noncoding RNAs (lncRNAs) are dysregulated in a number of cancer types, limited data are available on the expression and function of lncRNAs in melanoma metastasis. The primary objective of this study was to investigate the role of 6 metastasis-related lncRNAs in pairs of primary melanoma and matched lymph node metastatic tissues. Among the tested lncRNAs, HOTAIR was the most highly expressed in lymph node metastasis. The role of HOTAIR in melanoma cell motility and invasion was further evaluated by knocking down HOTAIR with siRNAs. Knockdown of HOTAIR resulted in the reduction of motility and invasion of human melanoma cell line A375, as assessed by wound healing assay and Matrigel-based invasion assay. siHOTAIR also suppressed the degradation of gelatin matrix, suggesting that HOTAIR promotes gelatinase activity. Together, our study shows that HOTAIR is overexpressed in metastatic tissue, which is associated with the ability of HOTAIR to promote melanoma cell motility and invasion. These data indicate that lncRNAs may be involved in the metastasis of melanoma and provide support for further evaluation of lncRNAs in melanoma.
[Show abstract][Hide abstract]ABSTRACT: Background:
The active metabolite of vitamin D 1α,25-dihydroxycholecalciferol (1,25D(3) ) has exhibited broad-spectrum antitumor activity in xenograft animal models. However, its activity against metastatic disease has not been extensively investigated.
Squamous cell carcinoma (SCC) or 1,25D(3) -resistant variant SCC-DR cells were treated with 1,25D(3) . Actin organization was examined by immunofluorescence assay. Cell migration was assessed by "wound" healing and chemotactic migration assays. Cell invasion was assessed by a Matrigel-based invasion assay and in situ zymography. Matrix metalloproteinase 2 (MMP-2) and MMP-9 expression and secretion were examined by immunoblot analysis and an enzyme-linked immunosorbent assay, respectively. E-cadherin expression was assessed by flow cytometry, immunoblot analysis, and immunohistochemistry. Knockdown of E-cadherin was achieved by small interfering RNA. An experimental metastasis mouse model was created by intravenous injection of tumor cells; and lung tumor development in the mice was assessed by magnetic resonance imaging, gross observation, and histology.
SCC cellular morphology and actin organization were altered by 10 nM 1,25D(3) . 1,25D(3) inhibited SCC cell motility and invasion, which were associated with reduced expression and secretion of MMP-2 and MMP-9, and 1,25D(3) promoted the expression of E-cadherin. These findings were not observed in SCC-DR cells. Knock down of E-cadherin rescued 1,25D(3) -inhibited cell migration. Intravenous injection of SCC or SCC-DR cells resulted in the establishment of extensive pulmonary lesions in saline-treated C3H mice. Treatment with 1,25D(3) resulted in a marked reduction in the formation of lung tumor colonies in mice that were injected with SCC cells, but not in mice that were injected with SCC-DR cells.
1,25D(3) suppressed SCC cell motility, invasion, and metastasis, partially through the promotion of E-cadherin-mediated cell-cell adhesion.
[Show abstract][Hide abstract]ABSTRACT: New strategies for the treatment of advanced melanoma are urgently required. The RAS/RAF/MAPK pathway and c-Src are deregulated in the majority of malignant melanomas, suggesting that they may interact functionally and are involved in the development and progression of the malignancy. Preclinical studies have demonstrated variable inhibition of melanoma cell growth by dasatinib in vitro. Src may act through different downstream signaling pathways. In the present study, we demonstrate that dasatinib induces changes in cell morphology, characterized by an arborized and contracted appearance, and accompanied by a reduction in cell proliferation in primary melanoma cells. This morphological change is demonstrated to be associated with the inhibition of nuclear translocation of activated ERK1/2. Together, these results indicate that Src may promote cell proliferation through the activation of the ERK signaling pathway in melanoma oncogenesis.
[Show abstract][Hide abstract]ABSTRACT: Oral squamous cell carcinoma (OSCC) is a common and lethal malignancy. Thus, improvement in current knowledge of molecular changes associated with OSCC is urgently needed to explore novel avenues of diagnostics and treatment of this disease. While aberrant expression of long non‑coding RNAs (lncRNAs) has been functionally associated with certain types of cancer, including lung, breast and prostate carcinomas, their expression pattern and biological relevance in OSCC is currently unknown. In the present study, the relative abundance of a collection of lncRNAs in tissue or saliva samples from OSCC patients was investigated. It was shown that subsets of lncRNAs are expressed across non‑tumor, tumor and metastatic tissue samples. Some detected lncRNAs were shown to be aberrantly expressed in cases of oral cancer and metastasis. Moreover, whole saliva contained a detectable amount of some lncRNAs, which appeared to be potential markers for OSCC. These findings suggest that the detection of lncRNAs in saliva may be used as a noninvasive and rapid diagnostic tool for the diagnosis of oral cancer.
[Show abstract][Hide abstract]ABSTRACT: Metastatic cell migration and invasion are regulated by altered adhesion-mediated signaling to the actin-based cytoskeleton via activated Src-FAK complexes. Src-suppressed C-kinase substrate (SSeCKS, the rodent orthologue of human Gravin/AKAP12), whose expression is downregulated by oncogenic Src and in many human cancers, antagonizes oncogenic Src pathways including those driving neovascularization at metastatic sites, metastatic cell motility and invasiveness. This is likely manifested through its function as a scaffolder of F-actin and signaling proteins such as cyclins, calmodulin, protein kinase C and A. Here we show that in contrast to its ability to inhibit haptotaxis, SSeCKS increased prostate cancer cell adhesion to fibronectin and type I collagen in a FAK-dependent manner, correlating with a relative increase in FAK(poY397) levels. In contrast, SSeCKS suppressed adhesion-induced Src activation (Src(poY416)) and phosphorylation of FAK at Y925, a known Src substrate site. SSeCKS also induced increased cell spreading, cell flattening, integrin β1 clustering and formation of mature focal adhesion plaques. An in silico analysis identified a Src-binding domain on SSeCKS(aa 153-166) that is homologous to the Src-binding domain of caveolin-1, and this region is required for SSeCKS-Src interaction, for SSeCKS-enhanced Src activity and sequestration to lipid rafts and for SSeCKS-enhanced adhesion of MAT-LyLu and CWR22Rv1 prostate cancer cells. Our data suggest a model in which SSeCKS suppresses oncogenic motility by sequestering Src to caveolin-rich lipid rafts, thereby disengaging Src from FAK-associated adhesion and signaling complexes.Oncogene advance online publication, 18 June 2012; doi:10.1038/onc.2012.218.