Effects of raloxifene on breast cancer cell migration and invasion through the actin cytoskeleton

PAK2 promotes proliferation, migration, and invasion of lung squamous cell carcinoma through LIMK1/cofilin signaling pathway

Although the p21-activated kinase 2 (PAK2) is an essential serine/threonine protein kinase, its role in lung squamous cell carcinoma (LUSC) progression has yet to be fully understood. We analyzed PAK2 mRNA levels and DNA copy numbers as well as protein levels by quantitative real-time PCR and immunohistochemical staining, respectively, in human LUSC tissues and adjacent normal tissues. Then, we used colony formation assays, cell counting kit-8 assays, matrigel invasion assays, wound healing assays and xenograft models in nude mice to investigate the functions of PAK2 in LUSC progression. We demonstrated that the mRNA levels, DNA copy numbers, and protein levels of PAK2 were up-regulated in human LUSC tissues than in adjacent normal tissues. In addition, a higher PAK2 expression was correlated with a poorer prognosis in LUSC patients. In the in vitro study, we found that PAK2 promoted cell growth, migration, invasion, EMT process, and cell morphology regulation in LUSC cells. Furthermore, PAK2 enhanced tumor cell proliferation, migration, and invasion by regulating actin dynamics through the LIMK1/cofilin signaling. Our findings implicated that the PAK2/LIMK1/cofilin signaling pathway is likely a potential clinical marker and therapeutic target for LUSC.

Molecular Characterisation of Uterine Endometrial Proteins during Early Stages of Pregnancy in Pigs by MALDI TOF/TOF

The molecular mechanism underlying embryonic implantation is vital to understand the correct communications between endometrium and developing conceptus during early stages of pregnancy. This study’s objective was to determine molecular changes in the uterine endometrial proteome during the preimplantation and peri-implantation between 9 days (9D), 12 days (12D), and 16 days (16D) of pregnant Polish Large White (PLW) gilts. 2DE-MALDI-TOF/TOF and ClueGO^TM approaches were employed to analyse the biological networks and molecular changes in porcine endometrial proteome during maternal recognition of pregnancy. A total of sixteen differentially expressed proteins (DEPs) were identified using 2-DE gels and MALDI-TOF/TOF mass spectrometry. Comparison between 9D and 12D of pregnancy identified APOA1, CAPZB, LDHB, CCT5, ANXA4, CFB, TTR upregulated DEPs, and ANXA5, SMS downregulated DEPs. Comparison between 9D and 16D of pregnancy identified HP, APOA1, ACTB, CCT5, ANXA4, CFB upregulated DEPs and ANXA5, SMS, LDHB, ACTR3, HP, ENO3, OAT downregulated DEPs. However, a comparison between 12D and 16D of pregnancy identified HP, ACTB upregulated DEPs, and CRYM, ANXA4, ANXA5, CAPZB, LDHB, ACTR3, CCT5, ENO3, OAT, TTR down-regulated DEPs. Outcomes of this study revealed key proteins and their interactions with metabolic pathways involved in the recognition and establishment of early pregnancy in PLW gilts.

Downregulation of Rac1/PAK1/LIMK1/cofilin signaling pathway in colon cancer SW620 cells treated with Chlorin e6 photodynamic therapy

BACKGROUND

Colorectal cancer is one of the most common gastrointestinal malignancies. Photodynamic therapy (PDT) is a novel and non-invasive treatment for tumors as PDT features small trauma, good applicability, andaccurate targeting. PDT may also be a potential treatment for colon cancer as itmay may induce suppressive effects on metastatic potential.. However, the molecular mechanism of the Chlorin e6 Photodynamic therapy (Ce6-PDT) inhibiting the migration of human colon cancer SW620 cells remains unclear.

METHODS

Scratch wound healing assay, scanning electron microscope, MTT, immunofluorescence and laser confocal technique were used to investigate the suppressive effects of Ce6-PDT on the SW620 cells migration, pseudopodia, viability and the actin cytoskeleton. The effect of Ce6-PDT on actin-Filaments and signaling molecules of the Rac1/PAK1/LIMK1/cofilin signaling pathway in SW620 cells were examined by western blot analysis. RNA interference (RNAi) technology was used to establish siRNA-Rac1/SW620 cells. The combined effects of Ce6-PDT and RNAi on colon cancer SW620 cells was investigated by the same technology and methods mentioned above to clarify the signal transduction effect of Rac1/PAK1/LIMK1/cofilin signaling pathway in Ce6-PDT caused inhibition of SW620 cell migration.

RESULTS

The healing and migration rate of the SW620 cells was significantly reduced and the cell pseudopodia were reduced or disappeared by Ce6-PDT. The Immunofluorescence and western blot analysis results showed that Ce6-PDT destroy microfilament's original structure and significantly downregulated F-actin protein expression. The Rac1/PAK1/LIMK1/cofilin signaling pathway was downregulated by Ce6-PDT. Furthermore, the RNAi significantly strengthened the effect of Ce6-PDT on colon cancer SW620 cells migration.

CONCLUSIONS

Actin cytoskeleton and protrusions of SW620 cells correlate with its migration ability. Ce6-PDT suppresses SW620 cells migration by downregulating the Rac1/PAK1/LIMK1/cofilin signaling pathway, and its suppressive effect was enhanced by knocking down Rac1 gene expression.

RGD functionalized chitosan nanoparticle mediated targeted delivery of raloxifene selectively suppresses angiogenesis and tumor growth in breast cancer

Acidic pH is a crucial intrinsic property of the microenvironment of most solid tumors. Hence, the use of pH sensitive tumor targeting nanoparticles is an attractive approach to enhance the therapeutic efficacy of anti-cancer agents in solid tumors. Chitosan nanoparticles (CHNPs) have been widely explored in the area of cancer drug delivery; nevertheless their true potential as a pH responsive targeted drug delivery vehicle in cancer therapy has not been deciphered yet as most of the research is limited to pH dependent stability and drug release. In the present study, we investigate the direct effect of pH in synergy with RGD peptide based targeting on the therapeutic efficacy of chitosan nanoparticles (RGD-CHNPs) in breast cancer. Furthermore, for the first time we performed a comprehensive study showing the anti-tumor, anti-migratory and anti-angiogenic effect of raloxifene (Rlx) loaded CHNPs in breast cancer. We prepared stable formulations of raloxifene encapsulated CHNPs and RGD-CHNPs by the nontoxic ionic gelation method. pH dependent studies revealed that NPs possess higher stability and zeta potential along with enhanced cellular uptake at acidic pH (as present in solid tumors) compared to physiological pH. Furthermore, RGD conjugation enhanced the in vitro cellular uptake of CHNPs in α_vβ₃ integrin expressing breast cancer cells and induced higher cellular apoptosis in breast cancer cells which was further augmented by lower pH. Moreover, Rlx-RGD-CHNPs significantly inhibited breast cancer cell migration and angiogenesis. In vivo studies showed that Cy5.5 conjugated RGD-CHNPs can distinctly visualize tumors and Rlx-RGD-CHNPs significantly inhibit breast tumor growth without causing any toxic effect to normal tissue as confirmed by hematology and blood biochemical studies. Therefore, RGD-CHNPs could potentially enhance the therapeutic efficacy of chemotherapeutic drugs due to the synergistic effect of pH responsiveness and tumor specific targeting in breast cancer.

Examination of the relationship between viscoelastic properties and the invasion of ovarian cancer cells by atomic force microscopy

The mechanical properties of cells could serve as an indicator for disease progression and early cancer diagnosis. This study utilized atomic force microscopy (AFM) to measure the viscoelastic properties of ovarian cancer cells and then examined the association with the invasion of ovarian cancer at the level of living single cells. Elasticity and viscosity of the ovarian cancer cells OVCAR-3 and HO-8910 are significantly lower than those of the human ovarian surface epithelial cell (HOSEpiC) control. Further examination found a dramatic increase of migration/invasion and an obvious decease of microfilament density in OVCAR-3 and HO-8910 cells. Also, there was a significant relationship between viscoelastic and biological properties among these cells. In addition, the elasticity was significantly increased in OVCAR-3 and HO-8910 cells after the treatment with the anticancer compound echinomycin (Ech), while no obvious change was found in HOSEpiC cells after Ech treatment. Interestingly, Ech seemed to have no effect on the viscosity of the cells. Ech significantly inhibited the migration/invasion and significantly increased the microfilament density in OVCAR-3 and HO-8910 cells, which was significantly related with the elasticity of the cells. An increase of elasticity and a decrease of invasion were found in OVCAR-3 and HO-8910 cells after Ech treatment. Together, this study clearly demonstrated the association of viscoelastic properties with the invasion of ovarian cancer cells and shed a light on the biomechanical changes for early diagnosis of tumor transformation and progression at single-cell level.

BMX activates Wnt/β-catenin signaling pathway to promote cell proliferation and migration in breast cancer

BACKGROUND

Breast cancer has become a dangerous killer for the female, which seriously threatened women's life, leading to huge pressures to society. The present study assessed the mechanism underlying the involvement of bone marrow tyrosine kinase on chromosome X (BMX) in breast cancer development.

METHODS

The expression of BMX was examined by qPCR and immunohistochemistry. The effect of BMX on cell proliferation and migration was detected by Clone formation assay and Transwell assay. In vitro study, the correlation of BMX with Wnt/β-catenin pathway was explored by western blot and TOP/FOP flash assay.

RESULTS

In the present study, we found that BMX was up-regulated in breast cancer, which was associated with the tumor differentiation and TNM stage. Oncogenic BMX enhanced the ability of breast cancer cell proliferation and migration. Furthermore, BMX could up-regulate the protein expression levels of p-β-catenin (Y142), p-β-catenin(Y654) and inhibit the expression level of p-β-catenin (S33/37), thus activating Wnt/β-catenin pathway in MCF-7 and MDA-MB-231 cells. In addition, we revealed that BMX promoted GSK3β phosphorylation, which suppressed the degradation of β-catenin.

CONCLUSIONS

In this study, we identified that BMX-activated Wnt/β-catenin signaling pathway, playing an oncogenic role in breast cancer, suggesting that BMX could become a potential treatment target of breast cancer.

IR-783 inhibits breast cancer cell proliferation and migration by inducing mitochondrial fission

IR-783, a near-infrared heptamethine cyanine dye, has been reported to possess cancer targeting and anticancer effects; However, the molecular mechanism by which IR-783 exhibits anti-breast cancer activity is unclear. In the present study, the inhibitory effects of IR-783 on the proliferation and migration of breast cancer cells were investigated. Our results revealed that IR-783 inhibited MDA-MB-231 and MCF-7 cell proliferation in a dose- and time-dependent manner by inducing cell cycle arrest at the G0/G1 phase. In addition, a Transwell assay demonstrated that IR-783 treatment suppressed the migratory ability of MDA-MB-231 and MCF-7 cells. Furthermore, IR-783 treatment decreased the expression levels of matrix metalloproteinase (MMP)-2 and MMP-9 in MDA-MB-231 cells. Furthermore, IR-783 induced MDA-MB-231 and MCF-7 cell mitochondrial fission, and also decreased the levels of ATP. This was accompanied with a decrease in polymerized filamentous actin, which is the fundamental component of filopodia at the cell surface. Collectively, the results of the present study demonstrated that IR-783 inhibited the proliferation and migration of MDA-MB-231 and MCF-7 cells by inducing mitochondrial fission and subsequently decreasing ATP levels, resulting in cell cycle arrest and filopodia formation suppression. These findings suggest that IR-783 may be developed into an effective novel drug for treating breast cancer.

TRPM7 promotes the epithelial-mesenchymal transition in ovarian cancer through the calcium-related PI3K / AKT oncogenic signaling

BACKGROUND

The epithelial-mesenchymal transition (EMT) is crucial for metastasis and positively regulated by calcium-related signaling. The melastatin-related transient receptor potential 7 (TRPM7) regulates a non-selective cation channel and promotes cancer metastasis. However, the mechanisms underlying the action of TRPM7 in ovarian cancer are unclear.

METHODS

The expression of TRPM7 and EMT markers (Vimentin, N-cadherin, Twist and E-cadherin) in ovarian cancer samples was detected. TRPM7was knockdown by shRNA in Ovarian cancer cell lines to examine calcium [Ca2+]i, EMT markers and PI3K/AKT markers. Various cellular assays, such as invasion and migration, were performed in vitro, and further confirmed in vivo.

RESULTS

TRPM7 expression is negatively correlated with E-cadherin, but positively with N-cadherin, Vimentin and Twist expression in ovarian cancer samples. TRPM7 depletion inhibited the migration and invasion in SKOV3 and OVCAR3 cells. In addition, TRPM7 silencing decreased the lung metastasis of SKOV3 tumors and prolonged the survival of tumor-bearing mice. Similar to that of TRPM7 silencing, treatment with MK886, a potent 5-lipoxygenase inhibitor to reduce TRPM7 expression, and/or BAPTA-AM, an intracellular calcium chelator, significantly mitigated the Epidermal growth factor (EGF) or Insulin-like growth factors (IGF)-stimulated migration, invasion, and the EMT in ovarian cancer cells by decreasing the levels of intracellular calcium [Ca2+]i. Furthermore, treatment with LY2904002, a PI3K inhibitor, also inhibited the migration, invasion, and treatment with both LY2904002 and BAPTA-AM further enhanced their inhibition in ovarian cancer cells. Moreover, treatment with BAPTA-AM mitigated the IGF-stimulated migration, invasion, particularly in TRPM7-silenced ovarian cancer cells. Finally, TRPM7 silencing attenuated the PI3K/AKT activation, which was enhanced by BAPTA-AM, MK886 or LY2904002 treatment in ovarian cancer cells.

CONCLUSIONS

TRPM7 silencing inhibited the EMT and metastasis of ovarian cancer by attenuating the calcium-related PI3k/AKT activation. Our findings suggest that TRPM7 may be a therapeutic target for intervention of ovarian cancer.

Moesin is an independent prognostic marker for ER-positive breast cancer

Moesin, a cytoskeletal protein belonging to the ezrin-radixin-moesin family serves important roles in cell motility, invasion and metastasis. Moesin has been demonstrated to be of prognostic significance in tumor progression, due to its role in the metastatic process; however, its role in breast cancer is not well characterized. In the present study, the moesin expression was determined using immunohistochemistry in 404 and 46 patients with breast cancer and fibroadenoma, respectively, and the associations between moesin expression and the clinical parameters and prognostic values were analyzed. The positive rate of moesin protein expression was 47.8% (193/404) in breast cancer tissues, which was significantly higher than in fibroadenoma tissues (15.2%, 14/46). Overexpression of moesin was significantly associated with advanced clinical stage (P=0.002), positive lymph node metastasis (P<0.0001), and estrogen receptor (ER; P=0.008) and progesterone receptor (P=0.026) status. Patients with high moesin expression had significantly lower recurrence-free survival time, compared with patient with low moesin expression. Notably, overexpression of moesin was significantly associated with poor prognosis in patients with ER-positive breast cancer, and in patients treated with tamoxifen. Using a Cox proportional hazard regression model, further analysis was conducted, which demonstrated that moesin overexpression was a predictive prognostic factor for reduced overall survival time in patients with ER-positive breast cancer, and in patients treated with tamoxifen. These results indicated that moesin may be a potential marker for poor prognosis in patients with ER-positive breast cancer treated with tamoxifen. In conclusion, moesin serves an important role in the progression of breast cancer, and may be a valuable marker of breast cancer prognosis.

Regulatory Actions of LH and Follicle-Stimulating Hormone on Breast Cancer Cells and Mammary Tumors in Rats

Gonadotrophins are mainly known to influence the body through the formation of gonadal steroids. However, receptors for luteinizing hormone (LH) and follicular-stimulating hormone (FSH) are present in a set of extra-gonadal tissues in humans and animals, but their functional relevance is uncertain. In this article, we present experimental evidence that, in T-47D breast cancer (BC) cells, FSH, and LH alter the expression of genes involved in adhesion, motility, and invasion through the activation of their receptors. Using miniarray technology we also found that LH influences the expression of a broad set of genes involved in cancer biology in T-47D cells. Interestingly, the regulatory actions of FSH and LH depend on the modality of exposure, with significant differences between pre-pubertal-like vs. post-menopausal-like amounts of gonadotrophins, but not after intermittent administration, representative of fertile life. We also studied the modulation of the circulating levels of gonadotrophins in an in vivo rat model of BC progression and observed a direct correlation with the extent of cancer growth. These results support the hypothesis that gonadotrophins may have direct effects on extra-gonadal tissues. They also highlight that gonadotrophins could potentially contribute to BC progression, particularly in post-menopausal women who typically have higher gonadotrophin levels. This research may ultimately lead to testing the use of gonadotrophin-modulating drugs in BC patients.

Enhanced cytotoxicity and apoptosis by raloxifene in combination with estrogen and methotrexate in human endometrial stromal cells

Endometrial hyperplasia is a condition that may lead to the development of endometrial carcinoma. Initially, changes of the endometrium are caused by the estrogen's hyperstimulation that may lead to the development of an irregular bleeding and the infertility problems. Therapy of endometrial hyperplasia is limited to medical and surgical approaches. During the past decade, the new types of drugs were developed for the treatment of the endometrial hyperplasia. Here, for the first time, we investigated the cytotoxic effects of the various combinations of estrogen, raloxifene, and methotrexate in human ThESC cell line as a possible potential treatment of the endometrial hyperplasia. Our aim was to investigate and to determine the most efficient combination of investigated drugs in ThESC cells during 24-hr period using MTT assay, FACS analysis, and immunofluorescence staining. Our results demonstrated that the combination of raloxifene with methotrexate efficiently induced both the cytotoxicity and apoptosis in ThESC cells when compared to their single effect, as well as to the effect of combined treatment of raloxifene with estrogen. The application of the low doses of methotrexate combined with raloxifene offers all advantages of a potential beneficial antitumor match in cancer chemoprevention and therapy.

Downregulation of LIMK1-ADF/cofilin by DADS inhibits the migration and invasion of colon cancer

This study aimed to explore whether the downregulation of LIM kinase 1 (LIMK1)-actin depolymerization factor (ADF, also known as destrin)/cofilin by diallyl disulfide (DADS) inhibited the migration and invasion of colon cancer. Previous studies have shown that silencing LIMK1 could significantly enhance the inhibitory effect of DADS on colon cancer cell migration and invasion, suggesting that LIMK1 was a target molecule of DADS, which needed further confirmation. This study reported that LIMK1 and destrin were highly expressed in colon cancer and associated with poor prognosis of patients with colon cancer. Also, the expression of LIMK1 was positively correlated with the expression of destrin. The overexpression of LIMK1 significantly promoted colon cancer cell migration and invasion. DADS obviously inhibited migration and invasion by suppressing the phosphorylation of ADF/cofilin via downregulation of LIMK1 in colon cancer cells. Furthermore, DADS-induced suppression of cell proliferation was enhanced and antagonized by the knockdown and overexpression of LIMK1 in vitro and in vivo, respectively. Similar results were observed for DADS-induced changes in the expression of vimentin, CD34, Ki-67, and E-cadherin in xenografted tumors. These results indicated that LIMK1 was a potential target molecule for the inhibitory effect of DADS on colon cancer cell migration and invasion.

Paxillin, a novel controller in the signaling of estrogen to FAK/N-WASP/Arp2/3 complex in breast cancer cells

Breast cancer is the major cause of cancer-related death in women. Its treatment is particularly difficult when metastasis occurs. The ability of cancer cells to move and invade the surrounding environment is the basis of local and distant metastasis. Cancer cells are able to remodel the actin cytoskeleton, which requires the recruitment of numerous structural and regulatory proteins that modulate actin filaments dynamics, including Paxillin or the Neural Wiskott-Aldrich Syndrome Protein (N-WASP). We show that 17-β estradiol (E2) induces phosphorylation of Paxillin and its translocation toward membrane sites where focal adhesion complexes are assembled. This cascade is triggered by a Gαi1/Gβ protein-dependent signaling of estrogen receptor α (ERα) to c-Src, focal adhesion kinase (FAK) and Paxillin. Within this complex, activated Paxillin recruits the small GTPase Cdc42, which triggers N-WASP phosphorylation. This results in the redistribution of Arp2/3 complexes at sites where membrane structures related to cell movement are formed. Recruitment of Paxillin, Cdc42 and N-WASP is necessary for cell adhesion, migration and invasion induced by E2 in breast cancer cells. In parallel, we investigated whether Raloxifene (RAL), a selective estrogen receptor modulator (SERMs), could inhibit or revert the effects of E2 in breast cancer cell movement. We found that, in the presence of E2, RAL acts as an ER antagonist and displays an inhibitory effect on estrogen-promoted cell adhesion and migration via FAK/Paxillin/N-WASP. Our findings identify an original mechanism through which estrogen regulates breast cancer cell motility and invasion via Paxillin. These results may have clinical relevance for the development of new therapeutic strategies for cancer treatment.

The Ultrastructure of MCF-7 Breast Cancer Cells after Vasodilator-Stimulated Phosphoprotein Knockdown

Inhibition of vasodilator-stimulated phosphoprotein (VASP) expression could modulate the adhesion and proliferation of breast cancer cells. However, the underlying mechanisms are not well defined. Here, we show that knockdown of the VASP changes the ultrastructure of human MCF-7 breast cancer cells. Transfection of VASP shRNA significantly lowered the expression of VASP protein in MCF-7 cells. In the shRNA-VASP group, immunofluorescence showed diminished presence of F-actin, and it was lower in the nucleus than in the cytoplasm. After VASP was inhibited, the MCF-7 cells were oval in shape with blunt lamellipodium, disappearance of the cristae of mitochondria, decreased microvilli and more vacuoles. Collectively, our findings elucidated the morphological mechanism that knockdown of the VASP changed the ultrastructure of MCF-7 cells.

Prolactin Promotes Breast Cancer Cell Migration through Actin Cytoskeleton Remodeling

The role of prolactin on breast cancer development and progression is debated. Breast cancer progression largely depends on cell movement and on the ability to remodel the actin cytoskeleton. In this process, actin-binding proteins are requested to achieve fibrillar actin de-polymerization and relocation at the cell membrane. Kinases such as focal adhesion kinase (FAK) are later required to form actin/vinculin-enriched structures called focal adhesion complexes, which mediate firm adhesion to the extracellular matrix. These controllers are regulated by c-Src, which forms multiprotein signaling complexes with membrane receptors and is regulated by a number of hormones, including -prolactin. We here show that breast cancer cells exposed to prolactin display an elevated c-Src expression and phosphorylation. In parallel, increased moesin and FAK expression and phosphorylation are found. These molecular changes are associated to relocation to the plasma membrane of cytoskeletal actin fibers and to increased horizontal cell movement. In conclusion, prolactin regulates actin remodeling and enhances breast cancer cell movement. This finding broadens the understanding of prolactin actions on breast cancer cells, highlighting new pathways that may be relevant to on breast cancer progression.

Effects of progesterone and medroxyprogesterone on actin remodeling and neuronal spine formation

Sex steroids are important regulators of neuronal cell morphology, and this is critical for gender differences in brain function and dysfunction. Neuronal morphology is controlled by multiprotein complexes including moesin (a member of the ezrin/radixin/moesin family), focal adhesion kinase (FAK), or the Wiskott-Aldrich syndrome protein-family verprolin homologous (WAVE1) protein, controlling dynamic remodeling of the cytoskeleton and cell membrane. We investigated the actions of natural progesterone (P) and of the synthetic progestin medroxyprogesterone acetate (MPA) on actin remodeling, focal adhesion complex formation, and actin branching in rat cortical neurons. Treatment with P and, to a lesser extent, MPA, increases the number and density of dendritic spines. P increases the phosphorylation of moesin, FAK, and WAVE1, and their redistribution toward cell membrane sites where spines are formed. Signaling to moesin is achieved by PR via a Gα/Gβ-dependent signaling to the small GTPase Ras homolog gene family, member A and its related kinase, Rho-associated kinase-2. In parallel, WAVE1 recruitment is triggered by a Gαi/Gβ-dependent signaling of PR to c-Src, FAK, and Rac1 GTPase. Rac1 recruits cyclin-dependent kinase-5, which phosphorylates WAVE1. Silencing of moesin, FAK, or WAVE1 abrogates the increase in dendritic spines induced by progesterone. In all applications, MPA is found to act similar to P, albeit with a lower efficacy. In conclusion, our findings indicate that the control of actin polymerization and branching and focal adhesion complex formation via moesin, FAK, and WAVE1 is a key function of progesterone receptor in neurons, which may be relevant for the regulation of dendritic spine turnover and neuronal plasticity.

DADS downregulates the Rac1-ROCK1/PAK1-LIMK1-ADF/cofilin signaling pathway, inhibiting cell migration and invasion

The aim of this study was to explore the molecular mechanisms of the diallyl disulfide (DADS)-mediated downregulation of LIM kinase-1 (LIMK1) and the consequent inhibition of the migration and invasion of human colorectal cancer cells. RNA interference technology was used to establish stable LIMK1-miRNA/SW480 cell lines. The effects of DADS and LIMK1 RNA interference on the migration and invasion of SW480 cells were observed by scratch wound healing assay and Transwell migration assay. The effects of DADS on signaling molecules of the Rac1-Rho kinase (ROCK)1/p21-activated kinase (PAK)1-LIM kinase (LIMK)1-actin depolymerizing factor (ADF)/cofilin pathway in SW480 cells were examined by RT-PCR and western blot analysis. The healing and migration rate of the SW480 cells was significantly reduced and the cell penetrating ability was significantly suppressed (P<0.05) following treatment with DADS (45 mg/l). The immunohistochemistry and western blot analysis results showed that DADS significantly downregulated LIMK1 protein expression and suppressed LIMK1 protein phosphorylation. Furthermore, the RT-PCR and western blot analysis results revealed that DADS suppressed Rac1, ROCK1, PAK1, LIMK1 and destrin mRNA and protein expression, as well as the protein phosphorylation of LIMK1 and cofilin 1. The data demonstrate that LIMK1 expression positively correlates with the SW480 cell migration and invasion ability. DADS downregulates the Rac1-ROCK1/PAK1-LIMK1-ADF/cofilin signaling pathway, suppressing SW480 cell migration and invasion.

Estrogen receptor-{alpha} promotes endothelial cell motility through focal adhesion kinase

Sex steroids play a key role in cell movement and tissue organization. Cell migration requires the integration of events that induce changes in cell structure such as protrusion, polarization and traction toward the direction of migration. These actions are driven by actin remodeling and are stabilized by the development of adhesion sites to extracellular matrix via transmembrane receptors linked to the actin cytoskeleton. Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase that facilitates cell migration via the control of the turnover of focal adhesion complexes. In this work, we demonstrated that 17β-estradiol (E(2)) regulates actin remodeling and cell movement in human umbilical vein endothelial cells through the recruitment of FAK. E(2) induces phosphorylation of FAK and its translocation toward membrane sites where focal adhesion complexes are assembled. This process is triggered via a Gα/Gβ protein-dependent, rapid extra-nuclear signaling of estrogen receptor-α (ERα) that interacts in a multiprotein complex with c-Src, phosphatidylinositol 3-OH kinase and FAK. Phosphorylation of FAK is fundamental for its activation, translocation to the plasmatic membrane and the subsequent formation of focal adhesion complexes. In conclusion, we found that ERα enhances endothelial cell motility through the dynamic control of actin arrangement and the formation of focal adhesion complexes. The identification of these processes broadens the understanding of the actions of estrogens on endothelial cells and could be relevant in physiological or pathological settings.

Raloxifene inhibits tumor growth and lymph node metastasis in a xenograft model of metastatic mammary cancer

BACKGROUND

The effects of raloxifene, a novel selective estrogen receptor modulator, were studied in a mouse metastatic mammary cancer model expressing cytoplasmic ERα.

METHODS

Mammary tumors, induced by inoculation of syngeneic BALB/c mice with BJMC3879luc2 cells, were subsequently treated with raloxifene at 0, 18 and 27 mg/kg/day using mini-osmotic pumps.

RESULTS

In vitro study demonstrated that the ERα in BJMC3879luc2 cells was smaller (between 50 and 64 kDa) than the normal-sized ERα (66 kDa) and showed cytoplasmic localization. A statistically significant but weak estradiol response was observed in this cell line. When BJMC3879luc2 tumors were implanted into mice, the ERα mRNA levels were significantly higher in females than in males. In vitro studies showed that raloxifene induced mitochondria-mediated apoptosis and cell-cycle arrest in the G1-phase and a decrease in the cell population in the S-phase. In animal experiments, tumor volumes were significantly suppressed in the raloxifene-treated groups. The multiplicity of lymph node metastasis was significantly decreased in the 27 mg/kg group. Levels of apoptosis were significantly increased in the raloxifene-treated groups, whereas the levels of DNA synthesis were significantly decreased in these groups. No differences in microvessel density in tumors were observed between the control and raloxifene-treated groups. The numbers of dilated lymphatic vessels containing intraluminal tumor cells were significantly reduced in mammary tumors in the raloxifene-treated groups. The levels of ERα mRNA in mammary tumors tended to be decreased in the raloxifene-treated groups.

CONCLUSION

These results suggest that the antimetastatic activity of raloxifene in mammary cancer expressing cytoplasmic ERα may be a crucial finding with clinical applications and that raloxifene may be useful as an adjuvant therapy and for the chemoprevention of breast cancer development.

Vascular endothelial growth factor C promotes cervical cancer metastasis via up-regulation and activation of RhoA/ROCK-2/moesin cascade

Background

The elevated expression of vascular endothelial growth factor C (VEGF-C) is correlated with clinical cervical cancer metastasis and patient survival, which is interpreted by VEGF-C functions to stimulate angiogenesis and lymphatic genesis. However, the direct impact of VEGF-C on cervical cancer cell motility remains largely unknown.

Methods

In this study, we investigated the effects of VEGF-C on actin cytoskeleton remodeling and on cervical cancer cell migration and invasion and how the actin-regulatory protein, moesin regulated these effects through RhoA/ROCK-2 signaling pathway.

Results

On cervical carcinoma cell line SiHa cells, exposure of VEGF-C triggered remodeling of the actin cytoskeleton and the formation of membrane ruffles, which was required for cell movement. VEGF-C significantly enhanced SiHa cells horizontal migration and three-dimensional invasion into matrices. These actions were dependent on increased expression and phosphorylation of the actin-regulatory protein moesin and specific moesin siRNA severely impaired VEGF-C stimulated-cell migration. The extracellular small GTPase RhoA/ROCK-2 cascade mediated the increased moesin expression and phosphorylation, which was discovered by the use of Y-27632, a specific inhibitor of Rho kinase and by transfected constitutively active, dominant-negative RhoA as well as ROCK-2 SiRNA. Furthermore, in the surgical cervical specimen from the patients with FIGO stage at cervical intra-epithelial neoplasia and I-II cervical squamous cell carcinoma, the expression levels of moesin were found to be significantly correlated with tumor malignancy and metastasis.

Conclusions

These results implied that VEGF-C promoted cervical cancer metastasis by upregulation and activation of moesin protein through RhoA/ROCK-2 pathway. Our findings offer new insight into the role of VEGF-C on cervical cancer progression and may provide potential targets for cervical cancer therapy.