Overexpression of RhoA promotes the proliferation and migration of cervical cancer cells

Novel Function of Nogo-A as Negative Regulator of Endothelial Progenitor Cell Angiogenic Activity: Impact in Oxygen-Induced Retinopathy

Endothelial Progenitor Cells (EPCs) can actively participate in revascularization in oxygen-induced retinopathy (OIR). Yet the mechanisms responsible for their dysfunction is unclear. Nogo-A, whose function is traditionally related to the inhibition of neurite function in the central nervous system, has recently been documented to display anti-angiogenic pro-repellent properties. Based on the significant impact of EPCs in retinal vascularization, we surmised that Nogo-A affects EPC function, and proceeded to investigate the role of Nogo-A on EPC function in OIR. The expression of Nogo-A and its specific receptor NgR1 was significantly increased in isolated EPCs exposed to hyperoxia, as well as in EPCs isolated from rats subjected to OIR compared with respective controls (EPCs exposed to normoxia). EPCs exposed to hyperoxia displayed reduced migratory and tubulogenic activity, associated with the suppressed expression of prominent EPC-recruitment factors SDF-1/CXCR4. The inhibition of Nogo-A (using a Nogo-66 neutralizing antagonist peptide) or siRNA-NGR1 in hyperoxia-exposed EPCs restored SDF-1/CXCR4 expression and, in turn, rescued the curtailed neovascular functions of EPCs in hyperoxia. The in vivo intraperitoneal injection of engineered EPCs (Nogo-A-inhibited or NgR1-suppressed) in OIR rats at P5 (prior to exposure to hyperoxia) prevented retinal and choroidal vaso-obliteration upon localization adjacent to vasculature; coherently, the inhibition of Nogo-A/NgR1 in EPCs enhanced the expression of key angiogenic factors VEGF, SDF-1, PDGF, and EPO in retina; CXCR4 knock-down abrogated suppressed NgR1 pro-angiogenic effects. The findings revealed that hyperoxia-induced EPC malfunction is mediated to a significant extent by Nogo-A/NgR1 signaling via CXCR4 suppression; the inhibition of Nogo-A in EPCs restores specific angiogenic growth factors in retina and the ensuing vascularization of the retina in an OIR model.

ZXDC enhances cervical cancer metastasis through IGF2BP3-mediated activation of RhoA/ROCK signaling

Metastasis in cervical cancer (CC) has a significant negative impact on patient survival, highlighting the urgent need for investigation in this area. In this study, we identified significant overexpression of zinc finger, X-linked, duplicated family member C (ZXDC) in CC tissue with metastasis, which correlates with poor outcomes for CC patients. We observed that overexpression of ZXDC promotes, while silencing of ZXDC inhibits the metastasis of CC cells both in vitro and in vivo. Additionally, our research demonstrated that ZXDC activated RhoA/ROCK signaling pathway, leading to enhanced cytoskeleton remodeling in CC cells. Besides, we found that IGF2BP3 plays an essential role in the activation of ZXDC on the RhoA/ROCK signaling pathway by stabilizing RhoA mRNA. These findings reveal a mechanism whereby ZXDC promotes the cervical cancer metastasis by targeting IGF2BP3/RhoA/ROCK pathway.

Advances in the development of Rho GTPase inhibitors

Rho guanosine triphosphatases (Rho GTPases), as members of the Ras superfamily, are GDP/GTP binding proteins that behave as molecular switches for the transduction of signals from external stimuli. Rho GTPases play essential roles in a number of cellular processes including cell cycle, cell polarity as well as cell migration. The dysregulations of Rho GTPases are related with various diseases, especially with cancers. Accumulating evidence supports that Rho GTPases play important roles in cancer development and progression. Rho GTPases become potential therapeutic targets for cancer therapy. And a number of inhibitors targeting Rho GTPases have been developed. In this review, we discuss their structural features, summarize their roles in cancer, and focus on the recent progress of their inhibitors, which are beneficial for the drug discovery targeting Rho GTPases.

Overexpression of ARHGAP30 suppresses growth of cervical cancer cells by downregulating ribosome biogenesis

We aimed to identify whether Rho GTPase activating proteins (RhoGAPs) were downregulated in cervical cancers and might be targeted to reduce the growth of cervical cancer using the GEO database and immunohistochemical analysis to identified changes in transcription and protein levels. We analyzed their proliferation, clone formation ability, and their growth as subcutaneous tumors in mice. To detect ARHGAP30 localization in cells, immunofluorescence assays were conducted. Mass spectrometry combined with immunoprecipitation experiments were used to identify binding proteins. Protein interactions were validated with co-immunoprecipitation assays. Western-blot and q-PCR were applied to analyze candidate binding proteins that were associated with ribosome biogenesis. Puromycin incorporation assay was used to detect the global protein synthesis rate. We identified that ARHGAP30 was the only downregulated RhoGAP and was related to the survival of cervical cancer patients. Overexpression of ARHGAP30 in cervical cancer cells inhibited cell proliferation and migration. ARHGAP30 immunoprecipitated proteins were enriched in the ribosome biogenesis process. ARHGAP30 was located in the nucleous and interacted with nucleolin (NCL). Overexpression of ARHGAP30 inhibited rRNA synthesis and global protein synthesis. ARHGAP30 overexpression induced the ubiquitination of NCL and decreased its protein level in Hela cells. The function of ARHGAP30 on cervical cancer cell ribosome biogenesis and proliferation was independent of its RhoGAP activity as assessed with a RhoGAP-deficient plasmid of ARHGAP30R55A . Overall, the findings revealed that ARHGAP30 was frequently downregulated and associated with shorter survival of cervical cancer patients. ARHGAP30 may suppress growth of cervical cancer by reducing ribosome biogenesis and protein synthesis through promoting ubiquitination of NCL.

LncRNA PAXIP1-AS1 fosters the pathogenesis of pulmonary arterial hypertension via ETS1/WIPF1/RhoA axis

Pulmonary arterial hypertension (PAH) is a life‐threatening disease featured with elevated pulmonary vascular resistance and progressive pulmonary vascular remodelling. It has been demonstrated that lncRNA PAXIP1‐AS1 could influence the transcriptome in PAH. However, the exact molecular mechanism of PAXIP1‐AS1 in PAH pathogenesis remains largely unknown. In this study, in vivo rat PAH model was established by monocrotaline (MCT) induction and hypoxia was used to induce in vitro PAH model using human pulmonary artery smooth muscle cells (hPASMCs). Histological examinations including H&E, Masson's trichrome staining and immunohistochemistry were subjected to evaluate the pathological changes of lung tissues. Expression patterns of PAXIP1‐AS1 and RhoA were assessed using qRT‐PCR and Western blotting, respectively. CCK‐8, BrdU assay and immunofluorescence of Ki67 were performed to measure the cell proliferation. Wound healing and transwell assays were employed to evaluate the capacity of cell migration. Dual‐luciferase reporter assay, co‐immunoprecipitation, RIP and CHIP assays were employed to verify the PAXIP1‐AS1/ETS1/WIPF1/RhoA regulatory network. It was found that the expression of PAXIP1‐AS1 and RhoA was remarkably higher in both lung tissues and serum of MCT‐induced PAH rats, as well as in hypoxia‐induced hPASMCs. PAXIP1‐AS1 knockdown remarkably suppressed hypoxia‐induced cell viability and migration of hPASMCs. PAXIP1‐AS1 positively regulated WIPF1 via recruiting transcriptional factor ETS1, of which knockdown reversed PAXIP1‐AS1‐mediated biological functions. Co‐immunoprecipitation validated the WIPF1/RhoA interaction. In vivo experiments further revealed the role of PAXIP1‐AS1 in PAH pathogenesis. In summary, lncRNA PAXIP1‐AS1 promoted cell viability and migration of hPASMCs via ETS1/WIPF1/RhoA, which might provide a potential therapeutic target for PAH treatment.

FluoSTEPs: Fluorescent biosensors for monitoring compartmentalized signaling within endogenous microdomains

Growing evidence suggests that many essential intracellular signaling events are compartmentalized within kinetically distinct microdomains in cells. Genetically encoded fluorescent biosensors are powerful tools to dissect compartmentalized signaling, but current approaches to probe these microdomains typically rely on biosensor fusion and overexpression of critical regulatory elements. Here, we present a novel class of biosensors named FluoSTEPs (fluorescent sensors targeted to endogenous proteins) that combine self-complementing split green fluorescent protein, CRISPR-mediated knock-in, and fluorescence resonance energy transfer biosensor technology to probe compartmentalized signaling dynamics in situ. We designed FluoSTEPs for simultaneously highlighting endogenous microdomains and reporting domain-specific, real-time signaling events including kinase activities, guanosine triphosphatase activation, and second messenger dynamics in live cells. A FluoSTEP for 3',5'-cyclic adenosine monophosphate (cAMP) revealed distinct cAMP dynamics within clathrin microdomains in response to stimulation of G protein-coupled receptors, showcasing the utility of FluoSTEPs in probing spatiotemporal regulation within endogenous signaling architectures.

Profiling the expression of pro-metastatic genes in association with the clinicopathological features of primary breast cancer

BACKGROUND

Metastasis accounts for ninety percent of breast cancer (BrCa) mortality. Cortactin, Ras homologous gene family member A (RhoA), and Rho-associated kinase (ROCK) raise cellular motility in favor of metastasis. Claudins (CLDN) belong to tight junction integrity and are dysregulated in BrCa. Thus far, epidemiologic evidence regarding the association of different pro-metastatic genes with pathological phenotypes of BrCa is largely inconsistent. This study aimed to determine the possible transcriptional models of pro-metastatic genes incorporate in holding the integrity of epithelial cell-cell junctions (CTTN, RhoA, ROCK, CLDN-1, CLDN-2, and CLDN-4), for the first time, in association with clinicopathological features of primary BrCa.

METHODS

In a consecutive case-series design, 206 newly diagnosed non-metastatic eligible BrCa patients with histopathological confirmation (30-65 years) were recruited in Tabriz, Iran (2015-2017). Real-time RT-PCR was used. Then fold changes in the expression of target genes were measured.

RESULTS

ROCK amplification was associated with the involvement of axillary lymph node metastasis (ALNM; ORadj. = 3.05, 95%CI 1.01-9.18). Consistently, inter-correlations of CTTN-ROCK (β = 0.226, P < 0.05) and RhoA-ROCK (β = 0.311, P < 0.01) were determined among patients diagnosed with ALNM+ BrCa. In addition, the overexpression of CLDN-4 was frequently observed in tumors identified by ALNM+ or grade III (P < 0.05). The overexpression of CTTN, CLDN-1, and CLDN-4 genes was correlated positively with the extent of tumor size. CTTN overexpression was associated with the increased chance of luminal-A positivity vs. non-luminal-A (ORadj. = 1.96, 95%CI 1.02-3.77). ROCK was also expressed in luminal-B BrCa tumors (P < 0.05). The estrogen receptor-dependent transcriptions were extended to the inter-correlations of RhoA-ROCK (β = 0.280, P < 0.01), ROCK-CLDN-2 (β = 0.267, P < 0.05), and CLDN-1-CLDN-4 (β = 0.451, P < 0.001).

CONCLUSIONS

For the first time, our findings suggested that the inter-correlations of CTTN-ROCK and RhoA-ROCK were significant transcriptional profiles determined in association with ALNM involvement; therefore the overexpression of ROCK may serve as a potential molecular marker for lymphatic metastasis. The provided binary transcriptional profiles need more approvals in different clinical features of BrCa metastasis.

Use of peripheral blood transcriptomic biomarkers to distinguish high-grade cervical squamous intraepithelial lesions from low-grade lesions

It is crucial to classify cervical lesions into high-grade squamous intraepithelial lesions (HSILs) and low-grade SILs (LSILs), as LSILs are conservatively treated by observation, based on an expectation of natural regression, whereas HSILs usually require electrosurgical excision. In the present study, peripheral blood gene expression profiles were analyzed to identify transcriptomic biomarkers distinguishing HSILs from LSILs. A total of 102 blood samples were collected from women with cervical SILs (66 HSIL and 36 LSIL) for microarray hybridization. Candidate gene signatures were identified using AdaBoost algorithms, and a predictive model was constructed using logistic regression to differentiate HSILs from LSILs. To correct for possible bias as a result of the limited sample size and to verify the stability of the predictive model, a two-fold cross validation and null set analysis was conducted over 1,000 iterations. The functions of the transcriptomic biomarkers were then analyzed to elucidate the pathogenesis of cervical SIL. A total of 10 transcriptomic genes (STMN3, TRPC4AP, DYRK2, AGK, KIAA0319L, GRPEL1, ZFC3H1, LYL1, ITGB1 and ARHGAP18) were identified. The predictive model based on the 10-gene panel exhibited well-discriminated power. A cross validation process using known disease status exhibited almost the same performance as that of the predictive model, whereas null-set analysis with randomly reassigned disease status exhibited much lower predictive performance for distinguishing HSILs from LSILs. These biomarkers were involved in the 'Rho GTPase cycle', 'mitochondrial protein import', 'oncogenic MAPK signaling', 'integrin cell surface interaction' and 'signaling by BRAF and RAF fusions'. In conclusion, peripheral blood gene expression analysis is a promising method for distinguishing HSILs from LSILs. The present study proposes 10 candidate genes that could be used in the future as diagnostic biomarkers and potential therapeutic targets for cervical SILs. A simple, non-invasive blood test would be clinically useful in the diagnosis and classification of patients with cervical SILs.

LINC02381 Promoted Cell Viability and Migration via Targeting miR-133b in Cervical Cancer Cells

Background

It has been proved that lncRNAs could function as CeRNA for miRNAs in tumor growth and metastasis for cervical cancer. This paper aims to identify the role of LINC02381 in cervical cancer cells.

Materials and Methods

RT-qPCR was utilized to measure the expression levels of LINC02381 in cervical cancer tissues and cells. MTT, colony formation assay, transwell assay, RT-qPCR, and Western blotting were performed to investigate the roles of LINC02381 in cervical cancer cells. RegRNA 2.0 was used to predict the miRNA-binding sites of LINC02381. Luciferase reporter assay and RT-qPCR were employed to confirm the sponging effect between miR-133b and LINC02381.

Results

This study showed that LINC02381 was up-regulated in cervical cancer cells and acted as an oncogene in the development of cervical cancer. LINC02381 promoted cell viability and metastasis via sponging miR-133b. Moreover, miR-133b could target its downstream mediator of RhoA and inhibit its expression.

Conclusion

Overall, our results indicated that LINC02381 functions as an oncogene in cervical cancer and could serve as a novel target for cervical cancer therapies in the future.

Rho GTPases in Gynecologic Cancers: In-Depth Analysis toward the Paradigm Change from Reactive to Predictive, Preventive, and Personalized Medical Approach Benefiting the Patient and Healthcare

Rho guanosine triphospatases (GTPases) resemble a conserved family of GTP-binding proteins regulating actin cytoskeleton dynamics and several signaling pathways central for the cell. Rho GTPases create a so-called Ras-superfamily of GTPases subdivided into subgroups comprising at least 20 members. Rho GTPases play a key regulatory role in gene expression, cell cycle control and proliferation, epithelial cell polarity, cell migration, survival, and apoptosis, among others. They also have tissue-related functions including angiogenesis being involved in inflammatory and wound healing processes. Contextually, any abnormality in the Rho GTPase function may result in severe consequences at molecular, cellular, and tissue levels. Rho GTPases also play a key role in tumorigenesis and metastatic disease. Corresponding mechanisms include a number of targets such as kinases and scaffold/adaptor-like proteins initiating GTPases-related signaling cascades. The accumulated evidence demonstrates the oncogenic relevance of Rho GTPases for several solid malignancies including breast, liver, bladder, melanoma, testicular, lung, central nervous system (CNS), head and neck, cervical, and ovarian cancers. Furthermore, Rho GTPases play a crucial role in the development of radio- and chemoresistance e.g. under cisplatin-based cancer treatment. This article provides an in-depth overview on the role of Rho GTPases in gynecological cancers, highlights relevant signaling pathways and pathomechanisms, and sheds light on their involvement in tumor progression, metastatic spread, and radio/chemo resistance. In addition, insights into a spectrum of novel biomarkers and innovative approaches based on the paradigm shift from reactive to predictive, preventive, and personalized medicine are provided.

Metformin Inhibit Cervical Cancer Migration by Suppressing the FAK/Akt Signaling Pathway

Background:

Metformin, an antidiabetic drug, has been previously reported to have anti-cancer activities. However, its role in the control of cancer cell migration remains elusive.

Methods:

To examine the possible effect of metformin on migration of cervical cancer cells. The related mechanisms were further determined by immunocytochemistry and Western’s blotting assay.

Results:

The results showed that metformin treatment substantially inhibited the migration ability of cervical cancer cells. Consistently, the filopodia and lamellipodia formation were depleted after exposure to metformin. The suppression of migration mediated through the regulatory proteins such as focal adhesion kinase (FAK), ATP-dependent tyrosine kinase (Akt), Rac1 and RhoA after metformin treatment.

Conclusion:

Metformin displays antimigration effects in cervical cancer cells by inhibiting filopodia and lamellipodia formation through the suppression of FAK, Akt and its downstream Rac1 and RhoA protein. We propose that metformin could be a novel potential candidate as an antimetastatic cancer drug in the cervical cancer management.

Relevance of Neurotrophin Receptors CD271 and TrkC for Prognosis, Migration, and Proliferation in Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide and often has a poor prognosis. The present study investigated the role of the low affinity nerve growth factor receptor CD271 as a putative therapy target in HNSCC. Neurotrophins that bind to CD271 also have a high affinity for the tropomyosin receptor kinase family (Trk), consisting of TrkA, TrkB, and TrkC, which must also be considered in addition to CD271. A retrospective study and functional in vitro cell line tests (migration assay and cell sorting) were conducted in order to evaluate the relevance of CD271 expression alone and with regard to Trk expression. CD271 and Trks were heterogeneously expressed in human HNSCC. The vast majority of tumors exhibited CD271 and TrkA, whereas only half of the tumors expressed TrkB and TrkC. High expression of CD271-positive cells predicted a bad clinical outcome of patients with HNSCC and was associated with distant metastases. However, the human carcinomas that also expressed TrkC had a reduced correlation with distant metastases and better survival rates. In vitro, CD271 expression marked a subpopulation with higher proliferation rates, but proliferation was lower in tumor cells that co-expressed CD271 and TrkC. The CD271 inhibitor LM11A 31 suppressed cell motility in vitro. However, neither TrkA nor TrkB expression were linked to prognosis or cell proliferation. We conclude that CD271 is a promising candidate that provides prognostic information for HNSCC and could be a putative target for HNSCC treatment.

Knockdown of RhoE Expression Enhances TGF-β-Induced EMT (epithelial-to-mesenchymal transition) in Cervical Cancer HeLa Cells

Cervical cancer with early metastasis of the primary tumor is associated with poor prognosis and poor therapeutic outcomes. Since epithelial-to-mesenchymal transition (EMT) plays a role in acquisition of the ability to invade the pelvic lymph nodes and surrounding tissue, it is important to clarify the molecular mechanism underlying EMT in cervical cancer. RhoE, also known as Rnd3, is a member of the Rnd subfamily of Rho GTPases. While previous reports have suggested that RhoE may act as either a positive or a negative regulator of cancer metastasis and EMT, the role of RhoE during EMT in cervical cancer cells remains unclear. The present study revealed that RhoE expression was upregulated during transforming growth factor-β (TGF-β)-mediated EMT in human cervical cancer HeLa cells. Furthermore, reduced RhoE expression enhanced TGF-β-mediated EMT and migration of HeLa cells. In addition, we demonstrated that RhoE knockdown elevated RhoA activity and a ROCK inhibitor partially suppressed the acceleration of TGF-β-mediated EMT by RhoE knockdown. These results indicate that RhoE suppresses TGF-β-mediated EMT, partially via RhoA/ROCK signaling in cervical cancer HeLa cells.

Crinamine Induces Apoptosis and Inhibits Proliferation, Migration, and Angiogenesis in Cervical Cancer SiHa Cells

Crinum asiaticum is a perennial herb widely distributed in many warmer regions, including Thailand, and is well-known for its medicinal and ornamental values. Crinum alkaloids contain numerous compounds, such as crinamine. Even though its mechanism of action is still unknown, crinamine was previously shown to possess anticancer activity. In this study, we demonstrate that crinamine was more cytotoxic to cervical cancer cells than normal cells. It also inhibited anchorage-independent tumor spheroid growth more effectively than existing chemotherapeutic drugs carboplatin and 5-fluorouracil or the CDK9 inhibitor FIT-039. Additionally, unlike cisplatin, crinamine induced apoptosis without promoting DNA double-strand breaks. It suppressed cervical cancer cell migration by inhibiting the expression of positive regulators of epithelial-mesenchymal transition SNAI1 and VIM. Importantly, crinamine also exerted anti-angiogenic activities by inhibiting secretion of VEGF-A protein in cervical cancer cells and blood vessel development in zebrafish embryos. Gene expression analysis revealed that its mechanism of action might be attributed, in part, to downregulation of cancer-related genes, such as AKT1, BCL2L1, CCND1, CDK4, PLK1, and RHOA. Our findings provide a first insight into crinamine's anticancer activity, highlighting its potential use as an alternative bioactive compound for cervical cancer chemoprevention and therapy.

Reversing the Tumor Target: Establishment of a Tumor Trap

Despite the tremendous progress made in the field of cancer therapy in recent years, certain solid tumors still cannot be successfully treated. Alongside classical treatments in the form of chemotherapy and/or radiotherapy, targeted treatments such as immunotherapy that cause fewer side effects emerge as new options in the clinics. However, these alternative treatments may not be useful for treating all types of cancers, especially for killing infiltrative and circulating tumor cells (CTCs). Recent advances pursue the trapping of these cancer cells within a confined area to facilitate their removal for therapeutic and diagnostic purposes. A good understanding of the mechanisms behind tumor cell migration may drive the design of traps that mimic natural tumor niches and guide the movement of the cancer cells. To bring this trapping idea into reality, strong efforts are being made to create structured materials that imitate myelinated fibers, blood vessels, or pre-metastatic niches and incorporate chemical cues such as chemoattractants or adhesive proteins. In this review, the different strategies used (or could be used) to trap tumor cells are described, and relevant examples of their performance are analyzed.

Wnt signaling in cervical cancer?

Cervical cancer (CC) is the second most common malignant cancer in women. CC is difficult to diagnose, has a high recurrence rate, and is resistant to systemic therapies; as a result, CC patients have a relatively poor prognosis. One potential link to CC is the Wnt signaling pathway and its downstream effectors, which regulate cell differentiation, proliferation, migration, and fate. The aberrant activation of Wnt signaling is associated with various cancers, including CC. Recent studies have shown that activating or inhibiting the intracellular signal transduction in this pathway can regulate cancer cell growth and viability. This review will summarize the experimental evidence supporting the significance of the Wnt signaling pathway in CC, and will also discuss the current clinical role of Wnt signaling in CC diagnosis, therapy, and prognosis.

Serum starvation induces abnormal spindle location, RhoA delocalization, and extension of intercellular bridge with the midbody

Serum starvation induces binucleation in HeLa cells, but the effects of serum starvation on mitosis and the significance of binucleation remain unknown. We investigated the effect of serum starvation on mitosis and analyzed the growth of binucleated cells. The frequency of binucleation caused by cytokinesis failure in DMEM without FBS (0% medium) was higher than that in DMEM with FBS (10% medium). In 0% medium, the metaphase spindle location was off-center, and RhoA localization significantly lacked symmetry. The frequency of the extension of intercellular bridge with the midbody in 0% medium was significantly higher than that in 10% medium. Moreover, all mononucleated mitotic cells caused bipolar mitosis and produced only mononucleated daughter cells, but binucleated cells produced various nucleated cells by multipolar mitosis in 0% medium. These results suggest that serum starvation may have various effects on mitosis, and binucleated cells may be related to formation of aneuploidy.

Rho kinase proteins display aberrant upregulation in vascular tumors and contribute to vascular tumor growth

BACKGROUND

The serine/threonine protein kinases ROCK1 and 2 are key RhoA-mediated regulators of cell shape and cytoskeletal dynamics. These proteins perform multiple functions in vascular endothelial cell physiology and are attractive targets for cancer therapy based on their roles as oncogenes and metastatic promoters. Given their critical functions in both of these processes, we hypothesized that molecular targeting of ROCK proteins would be exceedingly effective against vascular tumors such as hemangiomas and angiosarcomas, which are neoplasms composed of aberrant endothelial cells.

METHODS

In this study, we compared ROCK1 and 2 protein expression in a large panel of benign and malignant vascular tumors to that of normal vasculature. We then utilized shRNA technology to knockdown the expression of ROCK1 and 2 in SVR tumor-forming vascular cells, and evaluated tumor size and proliferation rate in a xenograft model. Finally, we employed proteomics and metabolomics to assess how knockdown of the ROCK paralogs induced alterations in protein expression/phosphorylation and metabolite concentrations in the xenograft tumors.

RESULTS

Our findings revealed that ROCK1 was overexpressed in malignant vascular tumors such as hemangioendotheliomas and angiosarcomas, and ROCK2 was overexpressed in both benign and malignant vascular tumors including hemangiomas, hemangioendotheliomas, hemangiopericytomas, and angiosarcomas. shRNA-mediated knockdown of ROCK2, but not ROCK1, in xenograft vascular tumors significantly reduced tumor size and proliferative index compared to control tumors. Proteomics and metabolomics analysis of the xenograft tumors revealed both overlapping as well as unique roles for the ROCK paralogs in regulating signal transduction and metabolite concentrations.

CONCLUSIONS

Collectively, these data indicate that ROCK proteins are overexpressed in diverse vascular tumors and suggest that specific targeting of ROCK2 proteins may show efficacy against malignant vascular tumors.

RhoA promotes epidermal stem cell proliferation via PKN1-cyclin D1 signaling

OBJECTIVE

Epidermal stem cells (ESCs) play a critical role in wound healing, but the mechanism underlying ESC proliferation is not well defined. Here, we explore the effects of RhoA on ESC proliferation and the possible underlying mechanism.

METHODS

Human ESCs were enriched by rapid adhesion to collagen IV. RhoA(+/+)(G14V), RhoA(-/-)(T19N) and pGFP control plasmids were transfected into human ESCs. The effect of RhoA on cell proliferation was detected by cell proliferation and DNA synthesis assays. Induction of PKN1 activity by RhoA was determined by immunoblot analysis, and the effects of PKN1 on RhoA in terms of inducing cell proliferation and cyclin D1 expression were detected using specific siRNA targeting PKN1. The effects of U-46619 (a RhoA agonist) and C3 transferase (a RhoA antagonist) on ESC proliferation were observed in vivo.

RESULTS

RhoA had a positive effect on ESC proliferation, and PKN1 activity was up-regulated by the active RhoA mutant (G14V) and suppressed by RhoA T19N. Moreover, the ability of RhoA to promote ESC proliferation and DNA synthesis was interrupted by PKN1 siRNA. Additionally, cyclin D1 protein and mRNA expression levels were up-regulated by RhoA G14V, and these effects were inhibited by siRNA-mediated knock-down of PKN1. RhoA also promoted ESC proliferation via PKN in vivo.

CONCLUSION

This study shows that the effect of RhoA on ESC proliferation is mediated by activation of the PKN1-cyclin D1 pathway in vitro, suggesting that RhoA may serve as a new therapeutic target for wound healing.

CD271 regulates the proliferation and motility of hypopharyngeal cancer cells

CD271 (p75 neurotrophin receptor) plays both positive and negative roles in cancer development, depending on the cell type. We previously reported that CD271 is a marker for tumor initiation and is correlated with a poor prognosis in human hypopharyngeal cancer (HPC). To clarify the role of CD271 in HPC, we established HPC cell lines and knocked down the CD271 expression using siRNA. We found that CD271-knockdown completely suppressed the cells’ tumor-forming capability both in vivo and in vitro. CD271-knockdown also induced cell-cycle arrest in G₀ and suppressed ERK phosphorylation. While treatment with an ERK inhibitor only partially inhibited cell growth, CDKN1C, which is required for maintenance of quiescence, was strongly upregulated in CD271-depleted HPC cells, and the double knockdown of CD271 and CDKN1C partially rescued the cells from G₀ arrest. In addition, either CD271 depletion or the inhibition of CD271-RhoA signaling by TAT-Pep5 diminished the in vitro migration capability of the HPC cells. Collectively, CD271 initiates tumor formation by increasing the cell proliferation capacity through CDKN1C suppression and ERK-signaling activation, and by accelerating the migration signaling pathway in HPC.

Galectin-3 Enhances Migration of Minature Pig Bone Marrow Mesenchymal Stem Cells Through Inhibition of RhoA-GTP Activity

Bone marrow mesenchymal stem cells (BM-MSCs) are used in tissue engineering because of their migration characters. However, BM-MSCs have limitations in terms of reaching injuries and self-renewal. Therefore, enhancement of BM-MSC migration is important for therapeutic applications. Here, we assessed whether galectin-3 (Gal-3) increases the migration of minature pig BM-MSCs. Gal-3 was knocked down by short hairpin RNA (shRNA) or overexpressed using a lentiviral vector in Wuzhishan minature pig BM-MSCs. Proliferation and migration assays showed that knockdown of Gal-3 impaired BM-MSC proliferation and migration, whereas Gal-3 overexpression promoted these behaviors. RhoA-GTP activity was upregulated in Gal-3 shRNA-transfected BM-MSCs, while Rac-1- and Cdc42-GTP showed no changes. Western blotting indicated downregulation of p-AKT (ser473) and p-Erk1/2 after serum starvation for 12 h in Gal-3-knockdown BM-MSCs. p-AKT (ser473) expression was upregulated after serum starvation for 6 h, and p-Erk1/2 expression was unchanged in Gal-3-overexpressing BM-MSCs. Treatment with C3 transferase or Y27632 enhanced migration, whereas Gal-3 knockdown impaired migration in treated cells. These results demonstrate that Gal-3 may enhance BM-MSC migration, mainly through inhibiting RhoA-GTP activity, increasing p-AKT (ser473) expression, and regulating p-Erk1/2 levels. Our study suggests a novel function of Gal-3 in regulating minature pig BM-MSC migration, which may be beneficial for therapeutic applications.

Eukaryotic Translation Initiation Factor 5A (EIF5A) Regulates Pancreatic Cancer Metastasis by Modulating RhoA and Rho-associated Kinase (ROCK) Protein Expression Levels

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers with an overall survival rate of less than 5%. The poor patient outcome in PDAC is largely due to the high prevalence of systemic metastasis at the time of diagnosis and lack of effective therapeutics that target disseminated cells. The fact that the underlying mechanisms driving PDAC cell migration and dissemination are poorly understood have hindered drug development and compounded the lack of clinical success in this disease. Recent evidence indicates that mutational activation of K-Ras up-regulates eIF5A, a component of the cellular translational machinery that is critical for PDAC progression. However, the role of eIF5A in PDAC cell migration and metastasis has not been investigated. We report here that pharmacological inhibition or genetic knockdown of eIF5A reduces PDAC cell migration, invasion, and metastasis in vitro and in vivo. Proteomic profiling and bioinformatic analyses revealed that eIF5A controls an integrated network of cytoskeleton-regulatory proteins involved in cell migration. Functional interrogation of this network uncovered a critical RhoA/ROCK signaling node that operates downstream of eIF5A in invasive PDAC cells. Importantly, eIF5A mediates PDAC cell migration and invasion by modulating RhoA/ROCK protein expression levels. Together our findings implicate eIF5A as a cytoskeletal rheostat controlling RhoA/ROCK protein expression during PDAC cell migration and metastasis. Our findings also implicate the eIF5A/RhoA/ROCK module as a potential new therapeutic target to treat metastatic PDAC cells.

Effects of Low-Dose Diethylstilbestrol Exposure on DNA Methylation in Mouse Spermatocytes

Evidence from previous studies suggests that the male reproductive system can be disrupted by fetal or neonatal exposure to diethylstilbestrol (DES). However, the molecular basis for this effect remains unclear. To evaluate the effects of DES on mouse spermatocytes and to explore its potential mechanism of action, the levels of DNA methyltransferases (DNMTs) and DNA methylation induced by DES were detected. The results showed that low doses of DES inhibited cell proliferation and cell cycle progression and induced apoptosis in GC-2 cells, an immortalized mouse pachytene spermatocyte-derived cell line, which reproduces primary cells responses to E2. Furthermore, global DNA methylation levels were increased and the expression levels of DNMTs were altered in DES-treated GC-2 cells. A total of 141 differentially methylated DNA sites were detected by microarray analysis. Rxra, an important component of the retinoic acid signaling pathway, and mybph, a RhoA pathway-related protein, were found to be hypermethylated, and Prkcd, an apoptosis-related protein, was hypomethylated. These results showed that low-dose DES was toxic to spermatocytes and that DNMT expression and DNA methylation were altered in DES-exposed cells. Taken together, these data demonstrate that DNA methylation likely plays an important role in mediating DES-induced spermatocyte toxicity in vitro.

The role of RhoA in vulvar squamous cell carcinoma: a carcinogenesis, progression, and target therapy marker

Ras homologue gene family member A (RhoA) is involved in tumor mobility, invasion, and metastasis. We detected RhoA expression in vulvar squamous cell carcinoma (VSCC) tissue, measured RhoA expression in the VSCC cell phenotype, and measured the expression of the relevant molecules after RhoA small interfering RNA (siRNA) transfection in SW962 cells. RhoA has a higher expression level in VSCC than normal vulva skin tissue and was positively associated with the International Federation of Gynecology and Obstetrics (FIGO) stage and differentiation; besides, VSCC patients with lymph node metastasis had higher positive RhoA expression. RhoA messenger RNA and protein expression was significantly reduced in the RhoA siRNA transfectants as compared with the negative control (NC) and mock-transfected cells (p < 0.05). The RhoA siRNA transfectants lead to low growth, G1 arrest, high apoptosis, low migration and invasion (p < 0.05), and suppressed lamellipodia formation as compared to NC and mock-transfected cells. Besides, matrix metalloproteinase-2 (MMP2), MMP9, and cyclinA1 protein expression was downregulated, while that of Bax was upregulated in the RhoA siRNA transfectants (p < 0.05). SW962 cell proliferation rates were significantly lovastatin dose-dependent. Lovastatin caused G1 arrest, high apoptosis, low migration and invasion (p < 0.05), and suppression of lamellipodia formation. Similar to the RhoA siRNA transfectants, lovastatin treatment downregulated RhoA, MMP2, MMP9, and cyclinA1 protein expression, while upregulating that of Bax as compared to that of the NC (p < 0.05). Abnormal RhoA expression in vulvar carcinoma is involved in tumor proliferation and invasion and may be a treatment target. The RhoA inhibitor lovastatin alters VSCC cell migration and proliferation and may be effective for treating VSCC.

Curcumin inhibits LPA-induced invasion by attenuating RhoA/ROCK/MMPs pathway in MCF7 breast cancer cells

Breast cancer generally shows poor prognosis because of its invasion and metastasis. Lysophosphatidic acid (LPA) induces and aggravates cancer invasion and metastasis by activating its downstream signal pathways. RhoA/ROCK/MMP signaling was found one of the LPA-induced pathways, which may be involved in invasion of breast cancer. Furthermore, we investigated whether this pathway was involved in curcumin's effect against LPA-induced invasion. LPA incubation was used to enhance invasion of MCF-7 breast cancer cells. RhoA expression was knocked-down by siRNA technique. MTT assay was used to evaluate the proliferation. Transwell assay was utilized to investigate the invasion ability of MCF-7 cells. Real-time PCR and Western blotting were used to assess the expressions of RhoA, ROCK1, ROCK2, MMP2 and MMP9 at both translational and transcriptional levels. The RhoA and ROCK activities were also evaluated. LPA incubation significantly boosted invasion rate of MCF-7. RhoA silencing by siRNA dramatically inhibited LPA-enhanced invasion. Concurrently, RhoA and ROCK activities and expression levels of RhoA, ROCK1, ROCK2, MMP2 and MMP9 were down-regulated by RhoA siRNA transfection. In order to avoid influence of cytotoxicity of curcumin, concentrations below 45 μmol/L were selected to further investigate the mechanism of curcumin's anti-invasion effect. Invasion of LPA-incubated MCF-7 cells was impaired by curcumin in a concentration-dependent manner. Concurrently, RhoA and ROCK activities and expression levels of RhoA, ROCK1, ROCK2, MMP2 and MMP9 were down-regulated by curcumin in a concentration-dependent manner. In conclusion, RhoA/ROCK/MMPs pathway activation is involved in LPA-induced invasion in MCF-7 cells; curcumin inhibited LPA-induced invasion in MCF-7 cells by attenuating RhoA/ROCK/MMPs pathway.