Synthetic Circular miR-21 Sponge as Tool for Lung Cancer Treatment.

Lung cancer is the most common cancer in the world and several miRNAs are associated with it. MiRNA sponges are presented as tools to inhibit miRNAs. We designed a system to capture miRNAs based on circular RNAs (circRNA). To demonstrate its usefulness, we chose miR-21, which is upregulated and implicated in lung cancer. We constructed a miR-21 sponge and inserted it into a vector that facilitates circular RNA production (Circ-21) to study its effect on growth, colony formation, and migration in lung cancer cell lines and multicellular tumor spheroids (MTS). Circ-21 induced a significant and time-dependent decrease in the growth of A549 and LL2 cells, but not in L132 cells. Furthermore, A549 and LL2 cells transfected with Circ-21 showed a lower number of colonies and migration than L132. Similar findings were seen in A549 and LL2 Circ-21 MTS, which showed a significant decrease in volume growth, but not in L132 Circ-21 MTS. Based on this, the miR-21 circular sponge may suppress the processes of tumorigenesis and progression. Therefore, our system based on circular sponges seems to be effective, as a tool for the capture of other miRNAs.

Circular Sponge against miR-21 Enhances the Antitumor Activity of Doxorubicin against Breast Cancer Cells.

Breast cancer is the most common type of cancer in women, with chemotherapy being the main strategy. However, its effectiveness is reduced by drug resistance mechanisms. miR-21 is upregulated in breast cancer that has been linked to drug resistance and carcinogenic processes. Our aim was to capture miR-21 with a circular sponge (Circ-21) and thus inhibit the carcinogenic processes and drug resistance mechanisms in which it participates. Proliferation, migration, colony formation, cell cycle, and poly [ADP-ribose] polymerase 1 (PARP-1) and vascular endothelial growth factor (VEGF) detection assays were performed with MCF7 breast cancer cells and MCF10A non-tumor cells. In addition, doxorubicin resistance tests and detection of drug resistance gene expression were performed in MCF7 cells. Reduction in proliferation, as well as migration and colony formation, increased PARP-1 expression, inhibition of VEGF expression and cell cycle arrest in G2/M phase were displayed in the Circ-21 MCF7, which were not observed in the MCF10A cells. Furthermore, in the MCF7 cells, the Circ-21 enhanced the antitumor activity of doxorubicin and decreased the expression of resistance genes: ABCA1, ABCC4, and ABCC5. Based on these results, the use of Circ-21 can be considered a first step for the establishment of an effective gene therapy in the treatment of breast cancer.

Double origin of the extensor hallucis longus muscle: a case report.

Most of the anatomic variations of the extensor hallucis longus (EHL) muscle are related to the tendon of insertion. We show a double origin of the EHL from the medial aspect of the fibula and the lateral aspect of the tibia. A 27-year-old male with a double closed fracture of tibia and fibula showed an involuntary extension of the big toe during foot plantar flexion after surgery. A tendon fibrosis by the fixation plates could be the cause of the foot functional alteration. Interestingly, the anatomic variation described could be related to the postsurgical foot dysfunction, since when the fibrotic tissue was removed the normal extension of big toe recovered. As illustrated in this case report, knowledge of anatomic variations is very useful, particularly in the context of foot surgery.

Specific Colon Cancer Cell Cytotoxicity Induced by Bacteriophage E Gene Expression under Transcriptional Control of Carcinoembryonic Antigen Promoter.

Colorectal cancer is one of the most prevalent cancers in the world. Patients in advanced stages often develop metastases that require chemotherapy and usually show a poor response, have a low survival rate and develop considerable toxicity with adverse symptoms. Gene therapy may act as an adjuvant therapy in attempts to destroy the tumor without affecting normal host tissue. The bacteriophage E gene has demonstrated significant antitumor activity in several cancers, but without any tumor-specific activity. The use of tumor-specific promoters may help to direct the expression of therapeutic genes so they act against specific cancer cells. We used the carcinoembryonic antigen promoter (CEA) to direct E gene expression (pCEA-E) towards colon cancer cells. pCEA-E induced a high cell growth inhibition of human HTC-116 colon adenocarcinoma and mouse MC-38 colon cancer cells in comparison to normal human CCD18co colon cells, which have practically undetectable levels of CEA. In addition, in vivo analyses of mice bearing tumors induced using MC-38 cells showed a significant decrease in tumor volume after pCEA-E treatment and a low level of Ki-67 in relation to untreated tumors. These results suggest that the CEA promoter is an excellent candidate for directing E gene expression specifically toward colon cancer cells.

Cancer stem cells and their implication in breast cancer.

BACKGROUND: The cancer stem cell (CSC) hypothesis on the origin of cancer has recently gained considerable support. CSCs are tumour cells with the capacity for self-renewal and differentiation that direct the origin and progression of the disease and may be responsible for relapse, metastasis and treatment failures. DESIGN: This article reviews breast CSCs (BCSCs) phenotyping, clinical implications and clinical trials focused on BCSCs in breast cancer. Relevant studies were found through PubMed and Clinicaltrials.gov databases. RESULTS: Cancer stem cells are identified and isolated using membrane and cell activity markers; in the case of BCSCs, these are CD44(+) /CD24(low/-) and show aldehyde dehydrogenase activity, alongside their capacity to grow and form mammospheres. The presence of stem cell properties is associated with a worse outcome. Hence, these cells have important clinical implications, and elucidation of the mechanisms underlying their activity will allow the development of novel effective therapies and diagnostic instruments, improving the prognosis of these patients. CONCLUSIONS: Standard treatments are directed against the tumour mass and do not eliminate CSCs. There is therefore a need for specific anti-CSC therapies, and numerous authors are investigating new targets to this end, as reported in this review. It is also necessary for clinical trials to be undertaken to allow this new knowledge to be applied in the clinical setting. However, there have been few trials on anti-BCSCs therapies to date.

ABC transporters as differentiation markers in glioblastoma cells.

UNLABELLED: Glioblastoma multiforme (GBM) is the most common primary malignant brain tumour, characterized by a high aggressivity, a huge heterogeneity attending a hierarchical model and resistance to therapy. Drug resistance has been correlated with the presence of the ABC efflux transporters which are able to exclude drugs for the cellular cytoplasm. In the nucleus of the GBM, initiating cells (ICs) can self-renew and give rise to cancer stem cells, which differ to the side population cells and the different cellular subtypes that form the mass around them. The ICs do not express or express ATP binding cassette (ABC) at very low levels, but this expression may increase with the differentiation process. We suggest that the differentiation process may be responsible of chemoresistance of the GBM cells. We compared three ABC transporters expression: ABCA1, MRP4 and MRP5, in the ICs obtained from 9 patients with GBM and their respective differentiated GBM cells. We show an overexpression of the three ABC transporters in the differentiated GBM cells in comparison to ICs. IMPLICATIONS OF THE HYPOTHESIS: The blockade of these ABC transporters could help to improve the drug effectivity and thus reduce the tumour growth and prevent the tumour recurrence.

Antitumor Effect of Traditional Drugs for Neurological Disorders: Preliminary Studies in Neural Tumor Cell Lines.

Glioblastoma multiforme is the most common malignant primary brain tumor in adults. Despite new treatments developed including immunomodulation using vaccines and cell therapies, mortality remains high due to the resistance mechanisms presented by these tumor cells and the function of the blood-brain barrier that prevents the entry of most drugs. In this context of searching for new glioblastoma therapies, the study of the existing drugs to treat neurological disorder is gaining great relevance. The aim of this study was to determine, through a preliminary in vitro study on human glioblastoma (A172, LN229), anaplastic glioma (SF268) and neuroblastoma (SK-N-SH) cell lines, the possible antitumor activity of the active principles of several drugs (levomepromazine, haloperidol, lacosamide, valproic acid, levetiracetam, glatiramer acetate, fingolimod, biperiden and dextromethorphan) with the ability to cross the blood-brain barrier and that are commonly used in neurological disorders. Results showed that levetiracetam, valproic acid, and haloperidol were able to induce a relevant synergistic antitumor effect when associated with the chemotherapy currently used in clinic (temozolomide). Regarding the mechanism of action, haloperidol, valproic acid and levomepromazine caused cell death by apoptosis, while biperiden and dextromethorphan induced autophagy. Fingolimod appeared to have anoikis-related cell death. Thus, the assayed drugs which are able to cross the blood-brain barrier could represent a possibility to improve the treatment of neural tumors, though future in vivo studies and clinical trials will be necessary to validate it.

Promotion of human adipose-derived stem cell proliferation mediated by exogenous nucleosides.

Adult stem cells are becoming the best option for regenerative medicine because they have low tumourigenic potential and permit autologous transplantation, even without in vitro culture. Our objectives were to evaluate the effects of exogenous nucleosides on the proliferation of hASCs (human adipose-derived stem cells), with or without co-treatment with 5-aza (5-azacytidine), and to analyse the expression of lamin A/C during cardiomyocyte differentiation of these cells. We isolated hASCs from human lipoaspirates that were positive for mesenchymal stem cell markers. We found that 5-aza induces a dose-dependent inhibition of hASC proliferation [IC50 (inhibitory concentration 50): 5.37 microM], whereas exogenous nucleosides significantly promote the proliferation of hASCs and partially revert the antiproliferative effect of the drug. Multipotentiality of isolated hASCs was confirmed by adipogenic, osteogenic and cardiomyogenic induction. 5-Aza-induced cells expressed cardiac troponins I and T and myosin light chain 2, myocardial markers that were directly correlated with lamin A/C expression. Our results support the importance of the nucleoside supplementation of media to improve conditions for the expansion and maintenance of hASCs in culture. In addition, the quantification of lamin A/C expression appears to be a good marker for the characterization of cardiomyocyte differentiation of stem cells that has rarely been used.

Novel MicroRNA Sponges to Specifically Modulate Gene Expression in Colon Cancer Cells.

MicroRNA (miRNA) sponges allow the selective blockade of a complete family of associated miRNAs, which induce post-transcriptional gene silencing in their target through binding to 3'UTR mRNA. miRNA-365 and miRNA-145 are downregulated in colorectal cancer (CRC) but not in healthy tissues. Based on this, we constructed two vectors by inserting miRNA sponges (one for miRNA-365 and other for miRNA-145), and used enhanced green fluorescent protein (EGFP) as a 3'UTR reporter gene to analyze the ability of each sponge to catch its respective miRNA. Quantitative polymerase chain reaction (qPCR) results corroborated that the expression levels of both miRNAs were lower in CRC cell lines than in normal colon cell lines. Flow cytometry analysis revealed a decrease of the EGFP expression levels in the cell lines transfected with both sponges, being higher on the normal cell line while CRC cell lines presented a minimal decline. Also, this decrease was inversely proportional to the levels of expression of both miRNAs obtained by qPCR. These results were corroborated by fluorescence microscopy, showing a similar decrease in fluorescence. We propose a new vector system to carry in a specific way the expression of genes to CRC cells without affecting healthy cells, preventing damage to healthy tissues.

Last Advances in Nanocarriers-Based Drug Delivery Systems for Colorectal Cancer.

Colorectal cancer is the third most common type of cancer in both, men and women. The development of metastasis is very frequent, especially in patients with advanced stage, who require intensive chemotherapy that often results in poor response and significant morbidity. The undesirable effects of intensive chemotherapy on normal cells and the development of multidrug resistance are two of the main causes of treatment failure. Recent advances in nanotechnology allow to target cancer cells using cytotoxic drugs without affecting normal cells. Nanocarriers such as liposomes, polymeric nanoparticles and carbon nanotubes, among others, are able to improve drug distribution and bioavailability, cytotoxic concentration in the tumor mass and drug delivery to tumor tissue and, at the same time, reduce side effects. Current research studies are being conducted to develop new biomaterials that improve the characteristics of these nanomolecules. Several preclinical assays have disclosed the efficacy of nanotherapy in colon cancer, although further clinical trials will be necessary to demonstrate its efficacy. This review discusses the current status and the potential advantages of using nanocarrier-based drug delivery systems for colorectal cancer.

Enhanced antitumoral activity of doxorubicin against lung cancer cells using biodegradable poly(butylcyanoacrylate) nanoparticles.

Doxorubicin (Dox) is widely used for the combined chemotherapy of solid tumors. However, the use of these drug associations in lung cancer has low antitumor efficacy. To improve its efficacious delivery and activity in lung adenocarcinoma cells, we developed a biodegradable and noncytotoxic nanoplatform based on biodegradable poly(butylcyanoacrylate) (PBCA). The reproducible formulation method was based on an anionic polymerization process of the PBCA monomer, with the antitumor drug being entrapped within the nanoparticle (NP) matrix during its formation. Improved drug-entrapment efficiencies and sustained (biphasic) drug-release properties were made possible by taking advantage of the synthesis conditions (drug, monomer, and surfactant-agent concentrations). Dox-loaded NPs significantly enhanced cellular uptake of the drug in the A549 and LL/2 lung cancer cell lines, leading to a significant improvement of the drug's antitumoral activity. In vivo studies demonstrated that Dox-loaded NPs clearly reduced tumor volumes and increased mouse-survival rates compared to the free drug. These results demonstrated that PBCA NPs may be used to optimize the antitumor activity of Dox, thus exhibiting a potential application in chemotherapy against lung adenocarcinoma.

Antitumor properties of natural compounds and related molecules.

Cancer is the main cause of death in developing countries. Its development requires multiple steps in which the occurrence of certain events determines the state transition from a normal to a tumor cell. These events are related to the loss of mechanisms that control various biological processes, which results from the accumulation of genetic alterations, including mutations, chromosomal rearrangements, and variations in gene copy number, as well as from epigenetic alterations. In general, chemotherapeutic agents used for toxicity treatments have shown limited antitumor activity, with a high recurrence rate. This has prompted major research efforts to identify novel effective and selective anti-tumor compounds. In this article, we review recent patents that protect the antitumor properties of natural compounds and related molecules derived from plants, animals, or microorganisms. We consider their structure, mechanism of action, molecular targets and, in some cases, the clinical trial phase reached. We also report on various natural agents that appear to prevent cancer development.

Modulation of multidrug resistance gene expression in peripheral blood mononuclear cells of lung cancer patients and evaluation of their clinical significance.

PURPOSE: Multidrug resistance is one of the major obstacles to the successful treatment of non-small cell lung cancer (NSCLC). An ability to identify molecular markers of drug resistance in peripheral blood cells in order to better target treatment would therefore be extremely useful in selecting therapy protocols for patients. The aim of the present study was to evaluate whether expression of resistance genes (MDR1, MRP3 and LRP) can predict clinical outcome in NSCLC patients treated with paclitaxel and carboplatin. METHODS: Peripheral blood samples were obtained from lung cancer patients before and after chemotherapy and expression of the resistance gene in polymononuclear cells was detected by real-time reverse-transcription polymerase chain reaction. The results were correlated with treatment response and overall survival, which was calculated according to the Kaplan-Meier method. RESULTS: MDR1 expression levels in PMNs rose rapidly within 24 h post-administration of paclitaxel and carboplatin, whereas MRP and LRP expression levels remained unchanged. However, no significant correlation was observed between MDR1 expression and the patients' survival or treatment response. CONCLUSIONS: Modulation of MDR1 gene expression in PMNs after lung cancer treatment with paclitaxel and carboplatin cannot be used as a prognosis marker in these patients.

Gef gene therapy enhances the therapeutic efficacy of cytotoxics in colon cancer cells.

The potential use of gene therapy to improve the response of patients with advanced cancer is being intensively analyzed. We evaluated the cytotoxic impact of the gef gene, a suicide gene, which has a demonstrated antiproliferative activity in tumor cells, in colon carcinoma cells in order to improve the antitumour effect of chemotherapeutic drugs used as first line treatment in the management of advanced colon cancer. We found that the gef gene induced a marked decrease in cell viability (50% in 24h) in T-84 cells through cell death by apoptosis. Interestingly, when gef gene expression was combined with drugs of choice in the clinical treatment of colon cancer (5-fluorouracil, oxaliplatin and irinotecan), a strong synergistic effect was observed with approximately a 15-20% enhancement of the antiproliferative effect. Our data demonstrate, for the first time, that gef gene expression induces significant growth arrest in colon cancer cells and that it is able to enhance the effect of some cytotoxic drugs compared with a single therapeutic approach. These results indicate the potential therapeutic value of the gef gene in colon cancer combination therapy.

E phage gene transfection associated to chemotherapeutic agents increases apoptosis in lung and colon cancer cells.

The limited ability of conventional therapies to achieve the long-term survival of metastatic lung and colon cancer patients suggests the need for new treatment options. In this respect, genes encoding cytotoxic proteins have been proposed as a new strategy to enhance the activity of drugs, and combined therapies involving such genes and classical antitumoral drugs have been studied intensively. The E gene from phiX174 encodes a membrane protein with a toxic domain that leads to a decrease in tumour cell growth rates. Therefore, in order to improve the anti-tumour effects of currently used chemotherapeutic drugs on cancer cells, we investigated the association of the E suicide gene with these antineoplastic drugs. The E gene has antitumoral effects in both lung and colon cancer cells. In addition, expression of this gene induces ultrastructural changes in lung cancer transfected cells (A-549), although the significance of these changes remains unknown. The effect of combined therapy (gene and cytotoxic therapy) enhances the inhibition of tumour cell proliferation in comparison to single treatments. Indeed, our in vitro results indicate that an experimental therapeutic strategy based on this combination of E gene therapy and cytotoxic drugs may result in a new treatment strategy for patients with advanced lung and colon cancer.

Multidrug resistance and rhabdomyosarcoma (Review).

Classical cytotoxic treatment of rhabdomyosarcoma (RMS) is often accompanied by significant morbidity and poor response. This cytotoxic therapy may induce a multidrug resistance (MDR) phenotype in RMS which is associated with decreased effectiveness of chemotherapy. The majority of MDR molecules belong to a family of ABC (ATP binding cassette) transporters. Studies of drug resistance in RMS suggest that there are various mechanisms acting simultaneously, which might explain the low percentage of long-term survival in this malignancy. Moreover, although cells exposed to cytotoxic agents increase expression of muscle differentiation markers indicating myogenic differentiation, multidrug resistance may be a major obstacle in differentiation therapy for RMS. This review briefly discusses the current knowledge of resistance in RMS and emphasizes the importance of understanding the different aspects of MDR status in these patients.

Synergistic antitumoral effect of combination E gene therapy and Doxorubicin in MCF-7 breast cancer cells.

The low effectiveness of conventional therapies to achieve the long-term survival of metastatic breast cancer patients calls for the development of novel options. Genes encoding cytotoxic proteins have been proposed as a new strategy to enhance the antiproliferative activity of drugs. Combined therapy using these genes and classical antitumoral drugs are under intensive study. The E gene from ϕX174 encodes a membrane protein with a toxic domain that leads to a decrease in the tumour cell growth rate. With the aim of improving the anti-tumour effect on breast cancer cells of the currently used chemotherapeutic drugs (Paclitaxel, Docetaxel and Doxorubicin), we investigated the association of E suicide gene with these drugs. The effect of the combined therapy (gene therapy and cytotoxic) was determined by treating transfected MCF-7 cells and multicellular tumour spheroids (MTS) with drugs gradient concentrations. Our results showed that E gene has a direct oncolytic effect inducing a significant decrease in the proliferation rate of the MCF-7 cells. The E gene antitumoral activity was mediated by the induction of apoptosis (mitochondrial pathway). In addition, a significant enhancement of proliferation inhibition was observed when E gene transfection was associated with cytotoxic drugs in comparison to single treatments. The use of the combined therapy E gene-Doxorubicin obtained the greatest effect on the MCF-7 growth arrest. This therapeutic association also induced a significant enhancement of the MTS volume growth inhibition. Anti-tumour activity of the chemotherapeutic drugs classically used in the treatment of breast cancer was enhanced by E gene. Our in vitro results indicate that experimental therapeutic strategy based in the combined therapy E gene and cytotoxic drugs may be of potential therapeutic value as a new strategy for patients with advanced breast cancer.

E phage gene transfection enhances sensitivity of lung and colon cancer cells to chemotherapeutic agents.

The E gene from ΦX174 encodes a membrane protein with a toxic domain that leads to a decrease in the tumour cell growth rate. With the aim of improving the antitumour effect on lung and colon cancer cells of the currently used chemotherapeutic drugs such as gemcitabine, carboplatin and paclitaxel, and 5-fluorouracil (5FU) plus folinic acid (FA) with irinotecan or oxaliplatine, we investigated a new combined therapy using these drugs associated to the transfection of E gene. Our results showed that E gene was able to decrease proliferation rate in A-549 and T-84 cells by inducing apoptotic the mitochondrial pathway. Significantly greater inhibition of proliferation was obtained using drugs in combination with E gene in comparison to single-agent treatments or controls. E gene combined with paclitaxel had the greatest effect on A-549 cells and combined with 5FU/FA/oxaliplatin on T-84 cells. Antitumour mechanisms of the chemotherapeutic drugs were enhanced by E gene, which itself has direct oncolytic effects inducing A-549 and T-84 apoptosis. Our in vitro results indicate that the combined therapy of E gene and cytotoxic drugs may be of potential therapeutic value as a new strategy for patients with advanced lung and colon cancer.

The cytotoxic activity of the phage E protein suppress the growth of murine B16 melanomas in vitro and in vivo.

Novel treatment modalities, including gene therapy, are needed for patients with advanced melanoma. The E gene from the phage varphiX174 encodes a 91-aa protein which lyses Escherichia coli by formation of a transmembrane tunnel structure. To evaluate whether this E gene has a cytotoxic impact on melanoma cells in vitro and in vivo, and could therefore be used as a new therapeutic strategy for this tumor type, we selected the B16-F10 murine melanoma cell line as a model. We used a nonviral gene delivery approach (pcDNA3.1/E plasmid) to study the inhibition of melanoma cells' proliferation in vitro and direct intratumoral injection of pcDNA3.1/E complexed with jetPEI to deliver E cDNA to rapidly growing murine melanomas, and found that the E gene has both a strong antiproliferative effect in B16-F10 cells in vitro and induces an efficient decrease in melanoma tumor volume in vivo (90% in 15 days). Interestingly, the GFP-E fusion protein expressed in melanoma cells was located in the mitochondria. In vitro and in vivo analysis demonstrated significant functional and morphological mitochondrial alterations accompanied by a significant increase of cytochrome c and active caspase-3 and -9 in transfected cells, which suggests that tumoral cell death is mediated by the mitochondrial apoptotic pathway. These results show that E gene expression in melanoma cells has an extraordinary antitumor effect, which means it may be a new candidate for an effective strategy for melanoma treatment.