Effect of all-trans-retinoic acid on integrin receptors of human cervical cancer (SiHa) cells

RGD-Functionalized Nanofibers Increase Early GFAP Expression during Neural Differentiation of Mouse Embryonic Stem Cells

Stem cell differentiation toward a specific lineage is controlled by its microenvironment. Polymer scaffolds have long been investigated to provide microenvironment cues; however, synthetic polymers lack the specific signaling motifs necessary to direct cellular responses on their own. In this study, we fabricated random and aligned poly(ε-caprolactone) nanofiber substrates, surface-functionalized with RGD viastrain-promoted azide-alkyne cycloaddition, that were used to investigate the role of a covalently tethered bioactive peptide (RGD) and nanofiber orientation on neural differentiation of mouse embryonic stem cells. Gene and protein expression showed neural differentiation progression over 14 days, with similar expression on RGD random and aligned nanofibers for neurons and glia over time. The high levels of glial fibrillary acidic protein expression at early time points were indicative of neural progenitors, and occurred earlier than on controls or in previous reports. These results highlight the influence of RGD binding versus topography in differentiation.

Studies on Multifunctional Effect of All-Trans Retinoic Acid (ATRA) on Matrix Metalloproteinase-2 (MMP-2) and Its Regulatory Molecules in Human Breast Cancer Cells (MCF-7)

Background. Vitamin A derivative all-trans retinoic acid (ATRA) is considered as a potent chemotherapeutic drug for its capability of regulating cell growth and differentiation. We studied the effect of ATRA on MMP-2 in MCF-7, human breast cancer cells, and the probable signaling pathways which are affected by ATRA on regulating pro-MMP-2 activity and expression. Methods. Gelatin zymography, RT-PCR, ELISA, Western blot, Immunoprecipitation, and Cell adhesion assay are used. Results. Gelatin zymography showed that ATRA caused a dose-dependent inhibition of pro-MMP-2 activity. ATRA treatment downregulates the expression of MT1-MMP, EMMPRIN, FAK, NF-kB, and p-ERK. However, expression of E-cadherin, RAR, and CRABP increased upon ATRA treatment. Binding of cells to extra cellular matrix (ECM) protein fibronectin reduced significantly after ATRA treatment. Conclusions. The experimental findings clearly showed the inhibition of MMP-2 activity upon ATRA treatment. This inhibitory effect of ATRA on MMP-2 activity in human breast cancer cells (MCF-7) may result due to its inhibitory effect on MT1-MMP, EMMPRIN, and upregulation of TIMP-2. This study is focused on the effect of ATRA on MMP, MMP-integrin-E-cadherin interrelationship, and also the effect of the drug on different signaling molecules which may involve in the progression of malignant tumor development.

Alkaline ceramidase 2 regulates beta1 integrin maturation and cell adhesion

The polypeptide core of the integrin beta1 subunit (beta1) is glycosylated sequentially in the endoplasmic reticulum and the Golgi complex to form beta1 precursor and mature beta1, respectively. The beta1 precursor to mature beta1 conversion, termed beta1 maturation, regulates the cell surface levels and function of beta1-containing integrins, beta1 integrins. Here we demonstrate that the human alkaline ceramidase 2 (ACER2), a Golgi enzyme, regulates beta1 maturation by controlling the generation of sphingosine. ACER2 overexpression inhibited beta1 maturation, thus leading to a decrease in the levels of mature beta1 in T-REx HeLa cells, whereas RNA interference-mediated knockdown of ACER2 enhanced beta1 maturation in MCF-7 cells. ACER2 overexpression decreased the cell surface levels of beta1 integrins, thus inhibiting cell adhesion to fibronectin or collagen, whereas ACER2 knockdown has the opposite effects. Treatment with all-trans retinoic acid (ATRA) increased both the expression of ACER2 and the generation of sphingosine in HeLa cells and inhibited beta1 maturation. ACER2 knockdown attenuated the inhibitory effects of ATRA on both beta1 maturation and cell adhesion. In contrast, treatment with phorbol myristate acetate (PMA), a protein kinase C activator, decreased the expression of ACER2 and sphingosine in T-REx HeLa cells, thus enhancing beta1 maturation. ACER2 overexpression inhibited the stimulatory effects of PMA on both beta1 maturation and cell adhesion. These results suggest that the ACER2/sphingosine pathway plays an important role in regulating beta1 maturation and cell adhesion mediated by beta1 integrins.

Aldo-keto reductase family 1, member B10 in uterine carcinomas: a potential risk factor of recurrence after surgical therapy in cervical cancer

Aldo-keto reductase family 1, member B10 (AKR1B10), an enzyme that converts retinals into retinols is known to detect in non-small cell lung carcinoma (squamous cell- and adeno-carcinomas), but is barely expressed in normal tissues. Since these types of carcinoma occur frequently in the uterus (like in the lung), AKR1B10 may also be overexpressed in two major types of uterine cancer, cervical cancer (CC), and endometrial cancer (EMC). The objective of this study is to investigate AKR1B10 expression in uterine cancer and to analyze its clinical significance. In samples from uterine cancer patients, AKR1B10 was detected in 6 out of 30 (20.0%) CC cases and 6 out of 38 (15.8%) EMC cases. Statistical analysis indicated that AKR1B10 expression was associated with tumor recurrence after surgery and keratinization of squamous cell carcinoma only in CC. Although retinol (a metabolic product by AKR1B10) was observed in the normal epithelium, the molecule was not observed in cancer cells of AKR1B10-positive CC samples suggesting that the recurrence in CC may not depend on the convert of retinals into retinols via AKR1B10, a potential indicator in the management of patients with CC.

Therapeutic effect of all-trans-retinoic acid (at-RA) on an autoimmune nephritis experimental model: role of the VLA-4 integrin

Background

Mercuric chloride (HgCl₂) induces an autoimmune nephritis in the Brown Norway (BN) rats characterized by anti-glomerular basement membrane antibodies (anti-GBM Ab) deposition, proteinuria and a severe interstitial nephritis, all evident at day 13 of the disease. We assessed the effects of all-trans retinoic acid (at-RA) in this experimental model. At-RA is a vitamin A metabolite which has shown beneficial effects on several nephropathies, even though no clear targets for at-RA were provided.

Methods

We separated animals in four different experimental groups (HgCl₂, HgCl₂+at-RA, at-RA and vehicle). From each animal we collected, at days 0 and 13, numerous biological samples: urine, to measure proteinuria by colorimetry; blood to determine VLA-4 expression by flow citometry; renal tissue to study the expression of VCAM-1 by Western blot, the presence of cellular infiltrates by immunohistochemistry, the IgG deposition by immunofluorescence, and the cytokines expression by RT-PCR. Additionally, adhesion assays to VCAM-1 were performed using K562 α4 transfectant cells. ANOVA tests were used for statistical significance estimation.

Results

We found that at-RA significantly decreased the serum levels of anti-GBM and consequently its deposition along the glomerular membrane. At-RA markedly reduced proteinuria as well as the number of cellular infiltrates in the renal interstitium, the levels of TNF-α and IL-1β cytokines and VCAM-1 expression in renal tissue. Moreover, we reported here for the first time in an in vivo model that at-RA reduced, to basal levels, the expression of VLA-4 (α4β1) integrin induced by mercury on peripheral blood leukocytes (PBLs). In addition, using K562 α4 stable transfectant cells, we found that at-RA inhibited VLA-4 dependent cell adhesion to VCAM-1.

Conclusion

Here we demonstrate a therapeutic effect of at-RA on an autoimmune experimental nephritis model in rats. We report a significant reduction of the VLA-4 integrin expression on PBLs as well as the inhibition of the VLA4/VCAM1-dependent leukocyte adhesion by at-RA treatment. Thereby we point out the VLA-4 integrin as a target for at-RA in vivo.

Evaluation of a selectively oncolytic adenovirus for local and systemic treatment of cervical cancer

Treatment options for disseminated cervical cancer remain inadequate. Here, we investigated a strategy featuring Ad5-Delta 24 RGD, an oncolytic adenovirus replication-competent selectively in cells defective in the Rb-p16 pathway, such as most cervical cancer cells. The viral fiber contains an alpha(v)beta(3) and alpha(v)beta(5) integrin-binding RGD-4C motif, allowing coxsackie-adenovirus receptor-independent infection. These integrins have been reported to be frequently upregulated in cervical cancer. Oncolysis of cervical cancer cells was similar to a wild-type control in vitro. In an animal model of cervical cancer, the therapeutic efficacy of Ad5-Delta 24 RGD could be demonstrated for both intratumoral and intravenous application routes. Biodistribution was determined following intravenous administration to mice. Further preclinical safety data were obtained by demonstrating lack of replication of the agent in human peripheral blood mononuclear cells. These results suggest that Ad5-Delta 24 RGD could be useful for local or systemic treatment of cervical cancer in patients with disease resistant to currently available modalities.

KCl cotransport is an important modulator of human cervical cancer growth and invasion

Cervical cancer is a major world health problem for women, but the pathophysiology of this disease has received scant attention. Here we show that the growth and invasion of cervical cancer cells are strongly linked the expression and activity of the KCl cotransporter (KCC), an important regulator of the ionic and cellular osmotic homeostasis. Functional assays of KCl cotransport activation by osmotic swelling, staurosporine, and N-ethylmaleimide indicate that removal of the N-terminal 117 amino acids from KCC1 produces a dominant-negative loss-of-function phenotype for KCl cotransport in human cervical cancer cells. The capability for regulatory volume decrease is much attenuated in the loss-of-function KCC mutant cervical cancer cells. The loss-of-function KCC mutant cervical cancer cells exhibit inhibited cell growth accompanied by decreased activity of the cell cycle gene products retinoblastoma and cdc2 kinase. Reduced cellular invasiveness is in parallel by reduced expression of alpha v beta 3 and alpha 6 beta 4 integrins, accompanied by decreased activity of matrix metalloproteinase 2 and 9. Inhibition of tumor growth in SCID mice confirms the crucial role of KCC in promoting cervical cancer growth and invasion. Thus, blockade of KCl cotransport may be a useful therapeutic adjunctive strategy to retard or prevent cervical cancer invasion.