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Effect of HMG-CoA Reductase Inhibition on Vascular Smooth Muscle Cells Extracellular Matrix Production: Role of RhoA
Cholesterol-lowering effects apart, statins can improve the endothelial function, stabilize the atherosclerotic plaques, decrease the oxidative stress and inflammation and inhibit the thrombogenic response by means of the inhibition of isoprenoids, which serve as lipid attachments for intracellular signaling molecules. We aimed to evaluate whether the effect of statins on RhoA activity mediate extracellular matrix production, particularly affecting collagen type I, in smooth muscle cells (SMCs). Our results showed that lovastatin decreased collagen expression in primary cultured chicken SMCs as determined by incorporation of [H<sup>3</sup>]-proline, RT-PCR and immunocytochemistry. This fall was parallel to that found in Rho A activity. Similar results were found when GGTI-298, a RhoA inhibitor, was added to the culture medium. Mevalonate or geranylgeranyl pyrophosphate reverted these effects. In order to elucidate the role of Rho A in these events we transfected the cell line A10 (rat SMCs) with constitutively active (G14V) or dominant negative RhoA (T19N) constructs. The last ones showed similar results regarding collagen production that those stated above in lovastatin treated primary SMC cultures. Constitutively active RhoA transfected cells showed the opposite effects. Next we performed a promoter activity assay to exclude post-transcriptional mechanisms implicated in these studies. We found a similar pattern in col1a2 promoter activity to that found in collagen expression. Our results have demonstrated that statins regulate the activation of RhoA through its isoprenylation, which is crucial for the regulation of extracellular matrix synthesis in SMCs.
Communication from Tubular Epithelial Cells to Podocytes through Sirt1 and Nicotinic Acid Metabolism
We have recently published that tubular epithelial cells affect the podocyte epigenome though nicotinic acid metabolism in diabetic nephropathy (DN), and we have named this relationship “proximal tubule–podocyte communication”. In this review, we describe this novel mechanism in the early stage of DN, focusing on the function of renal tubular Sirt1 and Sirt1-related nicotinic acid metabolism. Mainly, we discuss the following three findings. First, we described the details of proximal tubule–podocyte communication. Second, we explained how Sirt1 regulates albuminuria via epigenetic mechanisms. This means that repeated high glucose stress triggers the initial changes in proximal tubules, which lead to the epigenetically irreversible glomerular damages. However, proximal tubular Sirt1 overexpression can rescue these changes. Our previous data indicated that the decrease in Sirt1 expression in proximal tubules caused the reduction in glomerular Sirt1 and the subsequent increase in glomerular Claudin-1. It seemed plausible that some humoral mediator is released from proximal tubules, migrates to podocytes and glomeruli, and affects Sirt1 expression in podocytes. Third, we mentioned a mediator connecting this communication, nicotinamide mononucleotide (NMN). We suggest the potential of Sirt1 or NMN as not only a therapeutic target but also as a prognostic marker of very early stage DN.
Synergistic Combination of Doxorubicin and Paclitaxel Delivered by Blood Brain Barrier and Glioma Cells Dual Targeting Liposomes for Chemotherapy of Brain Glioma
Brain glioma has become a great threat to human health in decades. To maximize the therapeutic efficacy of brain glioma as well as minimize the side effects, drugs should be penetrated through the blood brain barrier (BBB) and then targeted to the brain carcinoma cells with effective concentration. A dual-ligand delivery strategy was employed to achieve both of these goals. Herein, both specific targeting ligand transferrin and cell-penetrating peptide TAT were conjugated onto liposomes (TF/TAT-LP) to develop a brain glioma dual-ligand delivery system. Synergistic combination of doxorubicin (DOX) and paclitaxel (PTX), compared with using them separately, could more efficiently suppress tumor aggravation. In vitro studies including cellular uptake and three-dimensional (3D) tumor spheroid penetration assays proved that TF/TAT-LP could target brain endothelial and carcinoma cells with deeply penetration through the endothelial monolayers and target to the core of the tumor spheroids. In vivo imaging proved that the TF/TAT-LP possesses the highest tumor distribution, which was also confirmed by fluorescent images of the brain section. Ultimately, the DOX and PTX-loaded TF/TAT-LP (TF/TAT-PTX/DOX-LP) shows the best anti-glioma effect with improvement of glioma bearing survival time. In conclusion, synergistic combination of doxorubicin and paclitaxel delivered by the TF/TAT-LP could efficiently target to the brain glioma with satisfying treatment efficiency, which may be a promising formulation for glioma therapy.
Inhibition of P-Glycoprotein Mediated Efflux of Paclitaxel by Coumarin Derivatives in Cancer Stem Cells: An In Silico Approach
P-glycoprotein (P-gp) is well known to cause multidrug resistance (MDR) in cancer cells. This MDR leads to cancer recurrence which is a major obstacle in cancer treatment. High P-gp expression has been observed in the population of cancer stem cells (CSCs) having self-renewal potential. Early detection and inhibition of these CSCs is directly beneficial to cancer treatment. In this study coumarin derivatives are used to inhibit efflux process and thereby enhance bioavailability of various drugs like paclitaxel (PTX). This drug is most commonly used for the treatment of cancers of breast, ovary, head and neck. Coumarin derivatives can be used to reduce the growth of breast cancer stem cells through P-gp mediated efflux inhibition and paclitaxel bioavailability enhancement. With the use of computational approaches including molecular docking simulation and pharmacophore study, few coumarin derivatives have been found to be more potential inhibitors of P-gp mediated efflux. Based on high affinity inhibitors, new coumarin derivatives have been designed and docked at active site cavity of P-gps. Some newly designed coumarin derivatives were found to be more potent due to their higher binding affinity towards target protein. The finding that newly designed coumarins can be exploited for inhibition of P-gp mediated efflux in order to enhance paclitaxel bioavailability and can inhibit breast cancer stem cell growth is significant for designing potent anticancer drugs.
Two Novel Heparin-binding Vascular Endothelial Growth Factor Splices, L-VEGF144 and L-VEGF138, are Expressed in Human Glioblastoma Cells
The expression levels of different vascular endothelial growth factor A (VEGF) isoforms are associated with the angiogenesis and the patient’s prognoses in human cancers. Ribosomes specifically scan from 5’ to 3’ CUG initiation codon in the long 5’-untranslated region (5’-UTR) of the VEGF mRNA, resulting in the generation of high mol wt VEGF isoform [call large VEGF (L-VEGF)]. Alternative splicing of VEGF mRNA transcripts results in several isoforms with distinct properties that are dependent up their exon compositions. In this study, we observed two novel kinds of splicing VEGF isoforms that transcripted at the first upstream CUG codon, and which we have named large-VEGF144 (LVEGF144), and large-VEGF138 (L-VEGF138). The expression levels of messenger RNA for the different VEGF splice forms were analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR). After DNA sequencing, the genetic structure of L-VEGF144 involved not only a partial exon 1, exon 6a, and exons 7-8, but also an unique 108- nucleotides insertion of VEGF intron 5 interposed between exon 1 and exon 6. At the same time, L-VEGF144 lacked most of the Nterminal fragments (exons 1-5). We further found that a specific detection model could easily and rapidly confirm the presence of L-VEGF144 mRNA fragments in the biopsies or cell lines via RT-PCR assay. In addition, we used visible fluorescent fusion proteins to prove that both L-VEGF144 and L-VEGF138 have nuclear localization ability. Taken together, the findings of this study indicate that, unlike previously identified isoforms, these novel VEGF isoforms are likely to suggest a further level of complexity in the angiogenic process.
A Review on Novel Breast Cancer Therapies: Photodynamic Therapy and Plant Derived Agent Induced Cell Death Mechanisms
This review article presents an extensive examination of risk factors for breast cancer, treatment strategies with special attention to photodynamic therapy and natural product based treatments. Breast cancer remains the most commonly occurring cancer in women worldwide and the detection, treatment, and prevention are prominent concerns in public health. Background information on current developments in treatment helps to update the approach towards risk assessment. Breast cancer risk is linked to many factors such as hereditary, reproductive and lifestyle factors. Minimally invasive Photodynamic therapy (PDT) can be used in the management of various cancers; it uses a light sensitive drug (a photosensitizer, PS) and a light of visible wavelength, to destroy targeted cancer cells. State of the art analyses has been carried out to investigate advancement in the search for the cure and control of cancer progression using natural products. Traditional medicinal plants have been used as lead compounds for drug discovery in modern medicine. Both PDT and plant derived drugs induce cell death via different mechanisms including apoptosis, necrosis, autophagy, cell cycle regulation and even the regulation of various cell signalling pathways.
Potential Clinical Use of Differentiated Cells From Embryonic or Mesencyhmal Stem Cells in Orthopaedic Problems
Stem cells are classified by their tissue source. Embryonic stem cells that are derived from the inner cell mass of blastocyst stage embryos are highly proliferative in their undifferentiated state. A multipotent type of mesenchymal stem cells is isolated from various types of tissues such as bone marrow, fat tissue etc. The dynamics of embryonic and adult stem cell cycles are profoundly dissimilar from the culture of stem cells. After improving the culture conditions and differentiation potentials, differentiated stem cells are the first cells to be preferred in modern regenerative medicine and tissue engineering. This review article focuses on the cell-based therapy of orthopedic problems. We explore the challenges associated with bone repair and regeneration using embryonic or mesenchymal stem cells that are in undifferentiated or/and differentiated condition. This paper also discusses optimizing the best cell type, differentiation condition and using them on bone tissue engineering for future investigations.
Mesenchymal Stem Cells for Ischemic Stroke: Progress and Possibilities
Stroke is the most common neurological cause of morbidity and mortality in industrialized countries, afflicting 15 million people every year. The numbers are expected to increase, mostly due to aging populations. One in five stroke patients dies, and one in three are left with permanent disabilities. </p> <p> Although some acute phase therapies such as intravenous recombinant tissue plasminogen activator (rt-PA) andendovascular treatment have been shown to improve ischemic stroke outcome, these therapies are available only for a small proportion of patients. </p> <p> The use of stem cells to replace brain cells lost during stroke is a long-term goal, and one which is difficult to achieve given that transplanted cells must integrate and restore neural pathways to regain function of damaged parts of the brain. Over the past decade the use of mesenchymal stromal cells (MSCs) as therapy has emerged as a particularly attractive option. </p> <p> MSCs are a class of multipotent, self-renewing cells that give rise to differentiated progeny when implanted into appropriate tissues. Herein, we present a review of the application of MSCs in ischemic stroke, including the source of MSCs, the route and timing of their delivery into the brain and the endpoints measured. Experimental data of transplantation of MSCs in animal stroke models suggest an improved functional recovery. The transplantation of MSCs influences a wide range of events by modulating the inflammatory environment, stimulating endogenous neurogenesis and angiogenesis and reducing the formation of glial scar, although the precise, underlying mechanism of this phenomenon remains unknown. The results from early clinical trials highlight the need to optimize variables such as cell selection and route of administration in order to translate these results into safe and successful clinical applications.
Betulinic Acid Kills Colon Cancer Stem Cells
Cancer stem cells (CSCs) are considered to be the origin of cancer and it is suggested that they are resistant to chemotherapy. Current therapies fail to eradicate CSCs and therefore selecting a resistant cell subset that is able to facilitate tumor recurrences. Betulinic acid (BetA) is a broad acting natural compound, shown to induce cell death via the inhibition of the stearoyl-CoA- desaturase (SCD- 1). This enzyme converts saturated fatty acids into unsaturated fatty acids and is over-expressed in tumor cells. Here we show that BetA induces rapid cell death in all colon CSCs tested and is able to affect the CSCs directly as shown, via the loss of clonogenic capacity. Similar results were observed with inhibition of SCD-1, suggesting that SCD-1 activity is indeed a vulnerable link in colon CSCs and can be considered an ideal target for therapy in colon cancer.
HOX Genes as Potential Markers of Circulating Tumour Cells
Circulating tumour cells (CTCs) have significant diagnostic potential as they can reflect both the presence and recurrence of a wide range of cancers. However, this potential continues to be limited by the lack of robust and accessible isolation technologies. An alternative to isolation might be their direct detection amongst other peripheral blood cells, although this would require markers that allow them to be distinguished from an exceptionally high background signal. This review assesses the potential role of HOX genes, a family of homeodomain containing transcription factors with key roles in both embryonic development and oncogenesis, as unique and possibly disease specific markers of CTCs.
Glial Cells – The Key Elements of Alzheimer´s Disease
Alzheimer’s disease (AD) is a complex neurodegenerative disorder with major clinical hallmarks of memory loss, dementia, and cognitive impairment. Besides the extensive neuron-oriented research, an increasing body of evidence suggests that glial cells, namely astrocytes, microglia, NG2 glia and oligodendrocytes, may play an important role in the pathogenesis of this disease. In the first part of this review, AD pathophysiology in humans is briefly described and compared with disease progression in routinely used animal models. The relevance of findings obtained in animal models of AD is also discussed with respect to AD pathology in humans. Further, this review summarizes recent findings regarding the role/participation of glial cells in pathogenesis of AD, focusing on changes in their morphology, functions, proteins and gene expression profiles. As for astrocytes and microglia, they are fundamental for the progression and outcome of AD either because they function as effector cells releasing cytokines that play a role in neuroprotection, or because they fail to fulfill their homeostatic functions, ultimately leaving neurons to face excitotoxicity and oxidative stress. Next, we turn our attention towards NG2 glia, a novel and distinct class of glial cells in the central nervous system (CNS), whose role in a variety of human CNS diseases has begun to emerge, and we also consider the participation of oligodendrocytes in the pathogenesis and progression of AD. Since AD is currently an incurable disease, in the last part of our review we hypothesize about possible glia-oriented treatments and provide a perspective of possible future advancements in this field.
Mesenchymal Stem Cells and Nano-Bioceramics for Bone Regeneration
Orthopedic disorders and trauma usually result in bone loss. Bone grafts are widely used to replace this tissue. Bone grafts excluding autografts unfortunately have disadvantages like evoking immune response, contamination and rejection. Autografts are of limited sources and optimum biomaterials that can replace bone have been searched for several decades. Bioceramics, which have the similar inorganic structure of natural bone, are widely used to regenerate bone or coat metallic implants. As people continuously look for a higher life quality, there are developments in technology almost everyday to meet their expectations. Nanotechnology is one of such technologies and it attracts everyone’s attention in biomaterial science. Nano scale biomaterials have many advantages like larger surface area and higher biocompatibility and these properties make them more preferable than micro scale. Also, stem cells are used for bone regeneration besides nano-bioceramics due to their differentiation characteristics. This review covers current research on nano-bioceramics and mesenchymal stem cells and their role in bone regeneration.
A Review of Gene Knockout Strategies for Microbial Cells
Background: Predicting the effects of genetic modification is difficult due to the complexity of metabolic net- works. Various gene knockout strategies have been utilised to deactivate specific genes in order to determine the effects of these genes on the function of microbes. Deactivation of genes can lead to deletion of certain proteins and functions. Through these strategies, the associated function of a deleted gene can be identified from the metabolic networks. </p><p> Methods: The main aim of this paper is to review the available techniques in gene knockout strategies for microbial cells. The review is done in terms of their methodology, recent applications in microbial cells. In addition, the advantages and disadvantages of the techniques are compared and discuss and the related patents are also listed as well. </p><p> Results: Traditionally, gene knockout is done through wet lab (in vivo) techniques, which were conducted through laboratory experiments. However, these techniques are costly and time consuming. Hence, various dry lab (in silico) techniques, where are conducted using computational approaches, have been developed to surmount these problem. </p><p> Conclusion: The development of numerous techniques for gene knockout in microbial cells has brought many advancements in the study of gene functions. Based on the literatures, we found that the gene knockout strategies currently used are sensibly implemented with regard to their benefits. </p><p>
Biomaterial and Stem Cell Interactions: Histological Biocompatibility
Advancements in biomaterials and stem cell technology have lead current medical technology to tissue engineering and regenerative medicine. Human engineered cartilage, bone, fascia, tendon, nerve and skin tissues have been used for the treatment of tissue injuries and degenerative diseases in combination with embryonic, fetal or adult stem and progenitor cells. Mesenchymal stem cells are one of the most extensively studied adult stem cell population and are widely utilized in cell therapies. Regeneration and 3-dimensional reconstruction of specialized connective tissues by combining differently originated micro and nanoscaled, natural or synthetic scaffolds with stem or progenitor cells are highly expected to guarantee patients to maintain acceptable life quality. In this review we discuss the important issues in biomaterial and stem cell interactions based on histological biocompatibility, updating recent basic research in this field and addressing possible future perspectives.
Comparative Proteomic Profiling of Extracellular Proteins between Normal and Gastric Cancer Cells
Gastric cancer is the second leading cause of cancer-related deaths worldwide. Gastric cancer is often detected at a late stage when treatment is difficult. Biomarkers for early detection and drug targets for gastric cancer therapy are critical for effective management of gastric cancer. Secreted proteins not only play integral roles in cancer progression and metastasis, they are also easily accessible. Secreted proteins within the tumor microenvironment are therefore an attractive source of biomarkers and drug targets. In this study, iTRAQ-based liquid chromatography/tandem mass spectrometry was used for comparative profiling of the secretomes of 11 gastric cancer cell lines versus a normal gastric epithelial cell line. Of the close to 800 proteins detected, about 600 proteins were detected to display differential expression in one or more gastric cancer cell lines compared to normal cells. These differentially expressed proteins predominantly have binding or enzymatic activities and are largely associated with cellular and metabolic processes. Overexpression of ARPC4 was validated in gastric cell lines and its novel function in gastric cancer cell migration and invasion demonstrated in vitro. The findings support the notion of ARPC4 as a potential biomarker/drug target for metastatic gastric cancer.
Possible Role of Cancer Stem Cells in Colorectal Cancer Metastasizing to the Liver
Colorectal cancer (CRC) is one of the most common cancers in the world. In recent decades, drug therapy and surgery have not achieved satisfactory results in curing CRC. The identification of cancer stem cells (CSCs) has provided a possible mechanistic explanation of CRC growth and metastasis. Traditional chemotherapy targets rapidly dividing cells, and since the CSCs can escape these therapies and become circulating cells, CSCs may be responsible for cancer relapse and metastasis. A better understanding of the roles of CSCs in the pathogenesis of primary CRC and its metastasis, as well as how these CSCs are regulated at the molecular level, is of paramount importance. In this review, we summarize the current understanding of the role of colorectal CSCs in CRC liver metastasis, and provide some insights on the potential implication of colorectal CSCs to better design therapeutic regimens and prevent CRC metastasis.
Role of the Receptor Tyrosine Kinase Axl and its Targeting in Cancer Cells
Aberrant expression and activation of receptor tyrosine kinases (RTK) is a frequent feature of tumor cells that may underlie tumor aggressiveness. Among RTK, Axl, a member of the Tyro3-Axl-Mer family, represents a potential therapeutic target in different tumor types given its over-expression which leads to activation of oncogenic signaling promoting cell proliferation and survival, as well as migration and invasion. Axl can promote aggressiveness of various cell types through PI3K/Akt and/or MAPK/ERK, and its expression can be transcriptionally regulated by multiple factors. Deregulated Axl expression and activation have been shown to be implicated in reduced sensitivity of tumor cells to target-specific and conventional antitumor agents, but the precise mechanism underlying these phenomena are still poorly understood. Several small molecules acting as Axl inhibitors have been reported, and some of them are undergoing clinical investigation. In this review, we describe Axl biological functions, its expression in cancer and in drug-resistant tumor cells and the development of inhibitors tailored to this receptor tyrosine kinase.
Current Approaches and Future Perspectives for In Vivo Clonal Tracking of Hematopoietic Cells
Over the past years, clonal tracking has gained the center stage as a unique technology capable to unveil population dynamics and hierarchical relationships in vivo. We here highlighted the main open questions related to the in vivo clonal behavior of hematopoietic cells with a particular focus on hematopoietic stem and progenitor cells and T cells as main targets of cell- and gene-therapies. We walked through the current methods applied for tracing in vivo dynamics and functions of hematopoietic cells in animal models and we described the results of early studies conducted on humans. We specifically focused our attention on the recent use of retroviral/lentiviral vector Integration Site (IS) analyses to follow stably marked clones and their progeny in vivo. We showed how this molecular tracking method can be successfully employed in human studies to unveil the clonal behavior of hematopoietic cells, describing pioneering works conducted on samples from gene therapy treated patients. Clonal tracking through IS identification still comes with a complex wet-experimental protocol and technical/analytical constraints. In this regard, we reviewed the features of the available computational tools for the identification and quantification of ISs and we highlighted the potential future improvements of IS-based tracking, as this technology is becoming a major source of information on in vivo fate and survival of engineered cells in humans.
Chemosensitization of Prostate Carcinoma Cells with a Receptor-directed Smac Conjugate
Background: Second mitochondrial activator of caspase (Smac) is a short mitochondrial peptide. When released from the mitochondria into the cytoplasm, it binds to inhibitor of apoptotic proteins (IAPs) within the cytoplasm and prevents them from inhibiting apoptosis. </p><p> Objective: Delivery of external synthetic Smac peptide into the cytoplasm of malignant cells could greatly improve the efficiency of apoptosis-inducing chemotherapeutic agents. </p><p> Method: In our study different conjugates based on the seven N-terminal amino acids AVPIAQK of Smac (SmacN7) were produced to obtain a cytoplasm-directed Smac variant. SmacN7 and a point mutant (AVPKAQK) were coupled either to rhodamine alone or to both rhodamine and undecylic aldehyde, which is an antagonist of the Lily-of-the-valley fragrance receptor. The fifth conjugate consisted of rhodamine coupled only to undecylic aldehyde, without SmacN7. The uptake of these five conjugates into three different human cell lines was characterized and quantified by confocal laser scanning microscopy and flow cytometry. A caspase apoptosis assay was performed for cells incubated with the five different conjugates after induction of apoptosis. </p><p> Results: The coupling of undecylic aldehyde to SmacN7 increased the cellular uptake of the correct and mutant conjugates. </p><p> Conclusion: Caspase 3/7 apoptosis tests after induction of apoptosis with staurosporine or UV irradiation showed that the coupling of SmacN7 with undecylic aldehyde resulted in a greatly increased adjuvant pro-apoptotic effect compared to the separate components and a mutant SmacN7 peptide sequence in the LNCaP prostate carcinoma cells compared to the benign prostate hyperplasia (BPH) cells and the human embryonal kidney (HEK) cells. </p><p>
Microfluidic Devices for Circulating Tumor Cells Isolation and Subsequent Analysis
The research of circulating tumor cells (CTCs) has drawn much attention in recent years. It is because of the potential values of CTCs in early diagnosis of cancer, management of clinical treatment, exploration of metastatic mechanism, and development of personalized medicine. However, isolating CTCs has been technically challenging due to their rare numbers in blood. Recently, a variety of microfluidic devices have been developed for CTC isolation, and these devices can realize high capture efficiency and high purity. While enumeration of CTCs has been achieved, further cellular and DNA analysis on the captured CTCs are less reported. In this article, we review recent reports in microfluidic methods for isolation of CTCs and subsequent cellular analysis on them.
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