Antineoplastic effect of compounds C14 and P8 on TNBC and radioresistant TNBC cells by stabilizing the K-Ras4BG13D/PDE6δ complex.

Introduction: Breast cancer (BC) is the leading cause of cancer-related deaths among women, with triple-negative breast cancer (TNBC) representing one of the most aggressive and treatment-resistant subtypes. In this study, we aimed to evaluate the antitumor potential of C14 and P8 molecules in both TNBC and radioresistant TNBC cells. These compounds were chosen for their ability to stabilize the complex formed by the overactivated form of K-Ras4BG13D and its membrane transporter (PDE6δ). Methods: The antitumor potential of C14 and P8 was assessed using TNBC cell lines, MDA-MB-231, and the radioresistant derivative MDA-MB-231RR, both carrying the K-Ras4B> G13D mutation. We investigated the compounds' effects on K-Ras signaling pathways, cell viability, and tumor growth in vivo. Results: Western blotting analysis determined the negative impact of C14 and P8 on the activation of mutant K-Ras signaling pathways in MDA-MB-231 and MDA-MB-231RR cells. Proliferation assays demonstrated their efficacy as cytotoxic agents against K-RasG13D mutant cancer cells and in inducing apoptosis. Clonogenic assays proven their ability to inhibit TNBC and radioresistant TNBC cell clonogenicity. In In vivo studies, C14 and P8 inhibited tumor growth and reduced proliferation, angiogenesis, and cell cycle progression markers. Discussion: These findings suggest that C14 and P8 could serve as promising adjuvant treatments for TNBC, particularly for non-responders to standard therapies. By targeting overactivated K-Ras and its membrane transporter, these compounds offer potential therapeutic benefits against TNBC, including its radioresistant form. Further research and clinical trials are warranted to validate their efficacy and safety as novel TNBC treatments.

Epigenetics as a determinant of radiation response in cancer.

Radiation therapy is a cornerstone of modern cancer treatment. Treatment is based on depositing focal radiation to the tumor to inhibit cell growth, proliferation and metastasis, and to promote the death of cancer cells. In addition, radiation also affects non-tumor cells in the tumor microenvironmental (TME). Radiation resistance of the tumor cells is the most common cause of treatment failure, allowing survival of cancer cell and subsequent tumor growing. Molecular radioresistance comprises genetic and epigenetic characteristics inherent in cancer cells, or characteristics acquired after exposure to radiation. Furthermore, cancer stem cells (CSCs) and non-tumor cells into the TME as stromal and immune cells have a role in promoting and maintaining radioresistant tumor phenotypes. Different regulatory molecules and pathways distinctive of radiation resistance include DNA repair, survival signaling and cell death pathways. Epigenetic mechanisms are one of the most relevant events that occur after radiotherapy to regulate the expression and function of key genes and proteins in the differential radiation-response. This article reviews recent data on the main molecular mechanisms and signaling pathways related to the biological response to radiotherapy in cancer; highlighting the epigenetic control exerted by DNA methylation, histone marks, chromatin remodeling and m6A RNA methylation on gene expression and activation of signaling pathways related to radiation therapy response.

Mutant p53 Gain-of-Function Induces Migration and Invasion through Overexpression of miR-182-5p in Cancer Cells.

The master-key TP53 gene is a tumor suppressor that is mutated in more than 50% of human cancers. Some p53 mutants lose their tumor suppressor activity and acquire new oncogenic functions, known as a gain of function (GOF). Recent studies have shown that p53 mutants can exert oncogenic effects through specific miRNAs. We identified the differentially expressed miRNA profiles of the three most frequent p53 mutants (p53R273C, p53R248Q, and p53R175H) after their transfection into the Saos-2 cell line (null p53) as compared with p53WT transfected cells. The associations between these miRNAs and the signaling pathways in which they might participate were identified with miRPath Software V3.0. QRT-PCR was employed to validate the miRNA profiles. We observed that p53 mutants have an overall negative effect on miRNA expression. In the global expression profile of the human miRNome regulated by the p53R273C mutant, 72 miRNAs were underexpressed and 35 overexpressed; in the p53R175H miRNAs profile, our results showed the downregulation of 93 and upregulation of 10 miRNAs; and in the miRNAs expression profile regulated by the p53R248Q mutant, we found 167 decreased and 6 increased miRNAs compared with p53WT. However, we found overexpression of some miRNAs, like miR-182-5p, in association with processes such as cell migration and invasion. In addition, we explored whether the induction of cell migration and invasion by the p53R48Q mutant was dependent on miR-182-5p because we found overexpression of miR-182-5p, which is associated with processes such as cell migration and invasion. Inhibition of mutant p53R248Q and miR-182-5p increased FOXF2-MTSS1 levels and decreased cell migration and invasion. In summary, our results suggest that p53 mutants increase the expression of miR-182-5p, and this miRNA is necessary for the p53R248Q mutant to induce cell migration and invasion in a cancer cell model.

Circulating miRNAs as Noninvasive Biomarkers for PDAC Diagnosis and Prognosis in Mexico.

Among malignant neoplasms, pancreatic ductal adenocarcinoma (PDAC) has one of the highest fatality rates due to its late detection. Therefore, it is essential to discover a noninvasive, early, specific, and sensitive diagnostic method. MicroRNAs (miRNAs) are attractive biomarkers because they are accessible, highly specific, and sensitive. It is crucial to find miRNAs that could be used as possible biomarkers because PDAC is the eighth most common cause of cancer death in Mexico. With the help of microRNA microarrays, differentially expressed miRNAs (DEmiRNAs) were found in PDAC tissues. The presence of these DEmiRNAs in the plasma of Mexican patients with PDAC was determined using RT-qPCR. Receiver operating characteristic curve analysis was performed to determine the diagnostic capacity of these DEmiRNAs. Gene Expression Omnibus datasets (GEO) were employed to verify our results. The Prisma V8 statistical analysis program was used. Four DEmiRNAs in plasma from PDAC patients and microarray tissues were found. Serum samples from patients with PDAC were used to validate their overexpression in GEO databases. We discovered a new panel of the two miRNAs miR-222-3p and miR-221-3p that could be used to diagnose PDAC, and when miR-221-3p and miR-222-3p were overexpressed, survival rates decreased. Therefore, miR-222-3p and miR-221-3p might be employed as noninvasive indicators for the diagnosis and survival of PDAC in Mexican patients.

Molecular Characterization of Patients with Cryptorchidism: Preliminary Search for an Expression Profile Related to That of Testicular Germ-Cell Tumors.

Cryptorchidism (CO) is a risk factor for the development of testicular germ-cell tumors (TGCT). This is supported by reports showing the persistence of gonocytes in CO patients. These cells are proposed to be related to the development of germ-cell neoplasia in situ (GCNIS), which is considered the precursor stage/lesion of TGCT. Therefore, it is proposed that some patients with CO could express some molecular markers related to TGCT. In this study, we analyzed testicular tissue samples from CO, TGCT, and controls. We determined the expression of POU5F1, PLAP, and KIT by immunohistochemistry and that of the hsa-miR-371-373 cluster, hsa-miR-367, and LATS2, PTEN, and IGFR1 genes by RT-qPCR. We then carried out a bioinformatic analysis to identify other possible candidate genes as tumor biomarkers. We found that 16.7% (2/12) of the CO patients presented increased expression of POU5F1, KIT, PLAP, hsa-miR-371-373, and hsa-miR-367 and decreased expression of LATS2 and IGF1R. Finally, the genes ARID4B, GALNT3, and KPNA6 were identified as other possible candidate tumor biomarkers. This is the first report describing the expression of the hsa-miR-371-373 cluster, hsa-miR-367, LATS2, and IGF1R in the testicular tissues of two CO patients with cells immune-positive to POU5F1, PLAP, and KIT, which is similar to what is observed in TGCT.

Transcriptomic profiles-based approach to decode the role of miR-122 in triple negative breast cancer.

miR-122 has been considered both as tumor suppressor miRNA and oncomiR in breast tumor phenotypes. However, the role of miR-122 in triple-negative breast cancer (TNBC) is still unknown. In this study, the clinical value of miR-122 was used to describe the transcriptomic landscape of TNBC tumors obtained from The Cancer Genome Atlas database. Low expression levels of miR-122 were associated with poor overall survival (OS) of TNBC patients than those with higher expression levels of miR-122. We identified gene expression profiles in TNBC tumors expressed lower or higher miR-122. Gene coexpression networks analysis revealed gene modules and hub genes specific to TNBC tumors with low or high miR-122 levels. Gene ontology and KEGG pathways analysis revealed that gene modules in TNBC with gain of miR-122 were related to cell cycle and DNA repair, while in TNBC with loss of miR-122 were enriched in cell cycle, proliferation, apoptosis and activation of cell migration and invasion. The expression of hub genes distinguished TNBC tumors with gain or loss of miR-122 from normal breast tissues. Furthermore, high levels of hub genes were associated with better OS in TNBC patients. Interestingly, the gene coexpression network related to loss of miR-122 were enriched with target genes of miR-122, but this did not observed in those with gain of miR-122. Target genes of miR-122 are oncogenes mainly associated with cell differentiation-related processes. Finally, 75 genes were identified exclusively associated to loss of miR-122, which are also implicated in cell differentiation. In conclusion, miR-122 could act as tumor suppressor by controlling oncogenes in TNBC.

The Role of microRNAs in the Gonocyte Theory as Target of Malignancy: Looking for Potential Diagnostic Biomarkers.

Some pediatric patients with cryptorchidism preserve cells with gonocyte characteristics beyond their differentiation period, which could support the theory of the gonocyte as a target for malignancy in the development of testicular neoplasia. One of the key molecules in gonocyte malignancy is represented by microRNAs (miRNAs). The goal of this review is to give an overview of miRNAs, a class of small non-coding RNAs that participate in the regulation of gene expression. We also aim to review the crucial role of several miRNAs that have been further described in the regulation of gonocyte differentiation to spermatogonia, which, when transformed, could give rise to germ cell neoplasia in situ, a precursor lesion to testicular germ cell tumors. Finally, the potential use of miRNAs as diagnostic and prognostic biomarkers in testicular neoplasia is addressed, due to their specificity and sensitivity compared to conventional markers, as well as their applications in therapeutics.

The E6 Oncoprotein of HPV16 AA-c Variant Regulates Cell Migration through the MINCR/miR-28-5p/RAP1B Axis.

The E6 oncoprotein of HPV16 variants differentially alters the transcription of the genes involved in migration and non-coding RNAs such as lncRNAs. The role of the lncRNA MINCR in cervical cancer and its relationship with variants of oncogenic HPV remain unknown. Therefore, the objective of this study was to analyze the effect of the E6 oncoprotein of the AA-c variant of HPV16 in cell migration through the MINCR/miR-28-5p/RAP1B axis. To explore the functional role of MINCR in CC, we used an in vitro model of C33-A cells with exogenous expression of the E6 oncoprotein of the AA-c variant of HPV16. Interfering RNAs performed MINCR silencing, and the expression of miR-28-5p and RAP1B mRNA was analyzed by RT-qPCR. We found that C33-A/AA-c cells expressed MINCR 8-fold higher compared to the control cells. There is an inverse correlation between the expression of miR-28-5p and RAP1B in C33-A/AA-c cells. Our results suggest that MINCR might regulate the expression of RAP1B through the inhibition of miR-28-5p in CC cells expressing the E6 oncoprotein of HPV16 AA-c. We report, for the first time, that the MINCR/miR-28-5p/RAP1B axis positively regulates cell migration in CC-derived cells that express the E6 oncoprotein of the AA-c variant of HPV16.

Analysis of the CAG tract length in the Androgen Receptor gene in Mexican patients with nonsyndromic cryptorchidism.

OBJECTIVES: Cryptorchidism is the most common genitourinary birth defect in live newborn males and is considered as an important risk factor for testicular germ cell tumors and infertility. The Androgen Receptor gene is important in this pathology due to its participation, mainly, in the inguinoscrotal phase of testicular descent. We determine the length of the CAG tract in the Androgen Receptor (AR) gene in Mexican patients with nonsyndromic cryptorchidism. METHODS: One hundred and 15 males were included; of these, 62 had nonsyndromic cryptorchidism and 53 were healthy volunteers. DNA was extracted from a peripheral blood samples, subsequently, the CAG tract in exon 1 of AR gene was amplified by PCR and sequenced. RESULTS: Mexican patients with nonsyndromic cryptorchidism presented 25.03 ± 2.58 repeats of CAG tract in the AR gene compared to 22.72 ± 3.17 repeats of CAG tract in Mexican healthy individuals (p≤0.0001; t value of 4.3). Furthermore, the deletion of codon 57 that corresponds to the deletion of a leucine residue at position 57 (Del L57) in the AR gene was found for the first time in a nonsyndromic cryptorchidism patient. This molecular alteration has been related previously to testicular germ cell tumor (TGCT). CONCLUSIONS: The CAG tract in the AR gene is longer in patients with nonsyndromic cryptorchidism than in healthy individuals, supporting the association between this polymorphism of the AR gene and nonsyndromic cryptorchidism in the Mexican population.

Deciphering the epigenetic network in cancer radioresistance.

Radiotherapy, in addition to surgery and systemic chemotherapy, remains the core of the current clinical management of cancer. Radioresistance is one of the major causes of disease progression and mortality in cancer; therefore, it is a significant challenge in the treatment of locally advanced, recurrent and metastatic cancer. Epigenetic mechanisms that control hallmarks of cancer have a key role in the development of radiation resistance of cancer cells. Recent advances in DNA methylation, histone modification, chromatin remodeling and non-coding RNAs identified in the control of signal transduction pathways in cancer and cancer stem cells have provided even greater promise in the improvement of understanding cancer radioresistance. Many epigenetic drugs that target epigenetic enzymes revert the radioresistant phenotypes decreasing the possibility that resistant cancer cells will develop refractory tumors to radiotherapy. Epigenetic profiles identified as regulators of DNA damage repair, hypoxia, cell survival, apoptosis and invasion are determinants in the development of tumor radioresistance; hence, they also are promising in personalized medicine to develop novel targeted therapies or biomarkers to follow-up the effectiveness of radiotherapy. Now, it is clear that radiotherapy can influence a complex epigenetic network for transcriptional reprogramming, enabling the cells to adapt and avoid the effect of radiotherapy. This review aims to highlight the epigenetic modifications identified in cancer radioresistance and to discuss approaches to disable epigenetic networks to increase the sensitivity and specificity of radiotherapy.

Cryptorchidism and Testicular Tumor: Comprehensive Analysis of Common Clinical Features and Search of SNVs in the KIT and AR Genes.

Allelic variants in genes implicated in the development of testicular germ cell tumor (TGCT) could be present in patients with cryptorchidism (CO). Currently; the mechanisms explaining this relationship are still unknown. In this study the common clinical features in patients with CO and TGCT and 6 variants of KIT and AR genes associated to TGCT were analyzed. Population analyzed included 328 individuals: 91 patients with CO; 79 with TGCT, 13 of them with previous CO diagnosis, and 158 healthy males. Of the 13 patients with TGCT and history of CO, one patient (7.7%) presented the heterozygous form of the variant rs121913507 and two patients (15.4%) presented homozygote genotype for the variant rs121913506 in KIT gene. Interestingly, the heterozygous form for the variant rs121913506 of KIT gene was identifying in all of 13 patients. The rs201934623, rs774171864, and rs12014709 variants of the AR gene did not show any clinical association. Our results strongly support that genetic component in CO could be conditioning for the development of TGCT. Notably, KIT gene variants might be determinants in the pathological association between TGCT and CO.

Curcumin stabilizes p53 by interaction with NAD(P)H:quinone oxidoreductase 1 in tumor-derived cell lines.

Curcumin is a natural phytochemical with potent anti-neoplastic properties including modulation of p53. Targeting p53 activity has been suggested as an important strategy in cancer therapy. The purpose of this study was to describe a mechanism by which curcumin restores p53 levels in human cancer cell lines. HeLa, SiHa, CaSki and MDA-MB-231 cells were exposed to curcumin and a pulse and chase and immunoprecipitation assays were performed. Here we showed that curcumin increases the half-life of p53 by a physical interaction between p53-NQO1 (p53 - NAD(P)H:quinone oxidoreductase 1) proteins after treatment with curcumin. Interestingly, the cell viability assay after treatment with curcumin showed that the cytotoxic activity was selectively higher in cervical cancer cells contained wild type p53 but not in breast cancer cells contained mutated p53. The cytotoxic effect of curcumin in cervical cancer cells was related to the complex p53-NQO1 that avoids the interaction between p53 and its negative regulator ubiquitin ligase E6-associated protein (E6AP). Finally, we demonstrated that in pancreatic epithelioid carcinoma cells (PANC1) that are knockout for NQO1, the reestablishment of NQO1 expression can stabilize p53 in presence of curcumin. Collectively, our findings showed that curcumin is necessary to promote the protein interaction of NQO1 with p53, therefore, it increases the half-life of p53, and permits the cytotoxic effect of curcumin in cancer cells containing wild type p53. Our findings suggest that the use of curcumin may reactivate the p53 pathway in cancer cells with p53 wild-type.

The epigenetic factor BORIS (CTCFL) controls the androgen receptor regulatory network in ovarian cancer.

The identification of prognostic biomarkers is a priority for patients suffering from high-grade serous ovarian cancer (SOC), which accounts for >70% of ovarian cancer (OC) deaths. Meanwhile, borderline ovarian cancer (BOC) is a low malignancy tumor and usually patients undergo surgery with low probabilities of recurrence. However, SOC remains the most lethal neoplasm due to the lack of biomarkers for early diagnosis and prognosis. In this regard, BORIS (CTCFL), a CTCF paralog, is a promising cancer biomarker that is overexpressed and controls transcription in several cancer types, mainly in OC. Studies suggest that BORIS has an important function in OC by altering gene expression, but the effect and extent to which BORIS influences transcription in OC from a genome-wide perspective is unclear. Here, we sought to identify BORIS target genes in an OC cell line (OVCAR3) with potential biomarker use in OC tumor samples. To achieve this, we performed in vitro knockout and knockdown experiments of BORIS in OVCAR3 cell line followed by expression microarrays and bioinformatics network enrichment analysis to identify relevant BORIS target genes. In addition, ex vivo expression data analysis of 373 ovarian cancer patients were evaluated to identify the expression patterns of BORIS target genes. In vitro, we uncovered 130 differentially expressed genes and obtained the BORIS-associated regulatory network, in which the androgen receptor (AR) acts as a major transcription factor. Also, FN1, FAM129A, and CD97 genes, which are related to chemoresistance and metastases in OC, were identified. In SOC patients, we observed that malignancy is associated with high levels of BORIS expression while BOC patients show lower levels. Our study suggests that BORIS acts as a main regulator, and has the potential to be used as a prognostic biomarker and to yield novel drug targets among the genes BORIS controls in SOC patients.

New insights into radioresistance in breast cancer identify a dual function of miR-122 as a tumor suppressor and oncomiR.

Radioresistance of tumor cells gives rise to local recurrence and disease progression in many patients. MicroRNAs (miRNAs) are master regulators of gene expression that control oncogenic pathways to modulate the radiotherapy response of cells. In the present study, differential expression profiling assays identified 16 deregulated miRNAs in acquired radioresistant breast cancer cells, of which miR-122 was observed to be up-regulated. Functional analysis revealed that miR-122 has a role as a tumor suppressor in parental cells by decreasing survival and promoting radiosensitivity. However, in radioresistant cells, miR-122 functions as an oncomiR by promoting survival. The transcriptomic landscape resulting from knockdown of miR-122 in radioresistant cells showed modulation of the ZNF611, ZNF304, RIPK1, HRAS, DUSP8 and TNFRSF21 genes. Moreover, miR-122 and the set of affected genes were prognostic factors in breast cancer patients treated with radiotherapy. Our data indicate that up-regulation of miR-122 promotes cell survival in acquired radioresistant breast cancer and also suggest that miR-122 differentially controls the response to radiotherapy by a dual function as a tumor suppressor an and oncomiR dependent on cell phenotype.

A meta-analysis of transcriptome datasets characterizes malignant transformation from melanocytes and nevi to melanoma.

Melanoma represents one of the most aggressive malignancies and has a high tendency to metastasize. The present study aims to investigate the molecular mechanisms of two pathways to cancer transformation with the purpose of identifying potential biomarkers. Our approach is based on a meta-analysis of gene expression profiling contrasting two scenarios: A model that describes a transformation pathway from melanocyte to melanoma and a second model where transformation occurs through an intermediary nevus. Data consists of three independent, publicly available microarray datasets from the Gene Expression Omnibus (GEO) database comprising samples from melanocytes, nevi and melanoma. The present analysis identified 808 differentially expressed genes (528 upregulated and 360 downregulated) in melanoma compared with nevi, and 2,331 differentially expressed genes (946 upregulated and 1,385 downregulated) in melanoma compared with melanocytes. Further analysis narrowed down this list, since 682 differentially expressed genes were found in both models (417 upregulated and 265 downregulated). Enrichment analysis identified relevant dysregulated pathways. This article also presented a discussion on significant genes including ADAM like decysin 1, neudesin neurotrophic factor, MMP19, apolipoprotein L6, C-X-C motif chemokine ligand (CXCL)8, basic, immunoglobulin-like variable motif containing and CXCL16. These are of particular interest because they encode secreted proteins hence represent potential blood biomarkers for the early detection of malignant transformation in both scenarios. Cytotoxic T-lymphocyte associated protein 4, an important therapeutic target in melanoma treatment, was also upregulated in both comparisons indicating a potential involvement in immune tolerance, not only at advanced stages but also during the early transformation to melanoma. The results of the present study may provide a research direction for studying the mechanisms underlying the development of melanoma, depending on its origin.

Evaluation of HIF-1α and iNOS in ischemia/reperfusion gastric model: bioimpedance, histological and immunohistochemical analyses.

Gastrointestinal ischemia/reperfusion (I/R) generates pathological alterations that could lead to death. Early ischemic damage markers could be used to guide therapy and improve outcomes. AIM: To relate hypoxia-inducible factor 1α (HIF-1α) activation and inducible nitric oxide synthase (iNOS) expression to gastric impedance changes due to I/R damage. METHODS: Experimental animals were randomly distributed into 3 groups: control, ischemia (30 min) and I/R (60 min). Gastric ischemia was generated by celiac artery clamping for 30 min, and then blood flow was restored for 60 min. Impedance spectra and biopsies of the glandular portion were obtained for histological and immunohistochemical analyses. Immunodetection of both HIF-1α and iNOS was performed. RESULTS: Under ischemia and I/R conditions, there was an increase (p<0.05) in the impedance parameters. Histologically, under ischemic conditions, edema and necrosis were observed in epithelium and significant vascular congestion. In I/R condition, alterations of the glandular and luminal integrity were found, which generated areas of epithelial erosion. Immunohistochemical analysis of HIF-1α revealed an increase (p<0.01) in the number of immunoreactive cells in the ischemia (35.7±13.9) and I/R (119.9±18.8) conditions compared to the control (0.8±1.2). Immunodetection of iNOS showed an increase (p<0.01) in the number of cells expressing iNOS under the ischemia (5.4±2.9) and I/R conditions (27.4±11.3) was observed compared to the control (0.4±0.8). CONCLUSION: Early changes in impedance in response to I/R is related to histopathological changes, the nuclear stabilization and translocation of HIF-1α as well as expression of iNOS.

C33-A cells transfected with E6*I or E6*II the short forms of HPV-16 E6, displayed opposite effects on cisplatin-induced apoptosis.

The HPV-16 E6/E7 bicistronic immature transcript produces 4 mature RNAs: the unspliced HPV-16 E6/E7pre-mRNA product and 3 alternatively spliced mRNAs. The 3 spliced mRNAs encode short forms of the E6 oncoprotein, namely E6*I, E6*II and E6^E7. In this study we showed that transfection of C-33A cells with monocistronic constructs of these cDNAs fused to GFP, produced different effects on apoptosis, after the treatment with cisplatin. Transfection of C-33A cells with the full-length E6-GFP oncoprotein resulted in a 50% decrease in cell death, while the transfection with the E6*I-GFP construct showed only a 25% of diminution of cell death, compared to the control cells. Transfection with the E6^E7-GFP or E7-GFP construct had no effect on the number of the apoptotic cells, compared with control cells. Conversely, transfection with the E6*II construct resulted in higher cell death than the control cells. Taken together, these results suggested that E6*I or E6*II, the short forms of HPV-16 E6, displayed opposite effects on cisplatin-induced apoptosis, when transfected in C-33A cells.

Tumor suppressor miR-29c regulates radioresistance in lung cancer cells.

Radiotherapy is an important treatment option for non-small cell lung carcinoma patients. Despite the appropriate use of radiotherapy, radioresistance is a biological behavior of cancer cells that limits the efficacy of this treatment. Deregulation of microRNAs contributes to the molecular mechanism underlying resistance to radiotherapy in cancer cells. Although the functional roles of microRNAs have been well described in lung cancer, their functional roles in radioresistance are largely unclear. In this study, we established a non-small cell lung carcinoma Calu-1 radioresistant cell line by continuous exposure to therapeutic doses of ionizing radiation as a model to investigate radioresistance-associated microRNAs. Our data show that 50 microRNAs were differentially expressed in Calu-1 radioresistant cells (16 upregulated and 34 downregulated); furthermore, well-known and novel microRNAs associated with resistance to radiotherapy were identified. Gene ontology and enrichment analysis indicated that modulated microRNAs might regulate signal transduction, cell survival, and apoptosis. Accordingly, Calu-1 radioresistant cells were refractory to radiation by increasing cell survival and reducing the apoptotic response. Among deregulated microRNAs, miR-29c was significantly suppressed. Reestablishment of miR-29c expression in Calu-1 radioresistant cells overcomes the radioresistance through the activation of apoptosis and downregulation of Bcl-2 and Mcl-1 target genes. Analysis of The Cancer Genome Atlas revealed that miR-29c is also suppressed in tumor samples of non-small cell lung carcinoma patients. Notably, we found that low miR-29c levels correlated with shorter relapse-free survival of non-small cell lung carcinoma patients treated with radiotherapy. Together, these results indicate a new role of miR-29c in radioresistance, highlighting their potential as a novel biomarker for outcomes of radiotherapy in lung cancer.

Epigenetic and risk factors of testicular germ cell tumors: a brief review.

Testicular germ cell cancer (TGCT) is the most common malignancy among young adult males, which has become important due to its increased incidence and mortality in the population worldwide. The etiology is multifactorial. Recent studies have shown some associations between the development of isolated TGCT and certain risk factors, such as exposure to endocrine disruptors, cryptorchidism, and family history of cancer, in order to identify the key pieces in carcinogenesis. Some of the most important findings in recent years is the association of different genes, such as c-KIT/KITLG, expression of the miR-371-373 cluster and protein expression as c-KIT and POU5F1 in the development of this neoplasia, and the identification of new molecular markers as TGFBR3 gene, identifying aberrant methylation patterns in promoter regions of several genes, expression of miR-1297 which regulates PTEN and protein expression as DMTR1. In the future, a multidisciplinary research strategy could provide valuable new insights into the etiology of TGCTs, which support clinical diagnosis of TGCT in the next years to increase survival in this kind of patients.

Resveratrol inhibits cell cycle progression by targeting Aurora kinase A and Polo-like kinase 1 in breast cancer cells.

The Aurora protein kinase (AURKA) and the Polo-like kinase-1 (PLK1) activate the cell cycle, and they are considered promising druggable targets in cancer therapy. However, resistance to chemotherapy and to specific small­molecule inhibitors is common in cancer patients; thus alternative therapeutic approaches are needed to overcome clinical resistance. Here, we showed that the dietary compound resveratrol suppressed the cell cycle by targeting AURKA and PLK1 kinases. First, we identified genes modulated by resveratrol using a genome-wide analysis of gene expression in MDA-MB-231 breast cancer cells. Transcriptional profiling indicated that 375 genes were modulated at 24 h after resveratrol intervention, whereas 579 genes were regulated at 48 h. Of these, 290 genes were deregulated in common at 24 and 48 h. Interestingly, a significant decrease in the expression of genes involved in the cell cycle, DNA repair, cytoskeleton organization, and angiogenesis was detected. In particular, AURKA and PLK1 kinases were downregulated by resveratrol at 24 h. In addition the BRCA1 gene, an AURKA/PLK1 inhibitor, was upregulated at 24 h of treatment. Moreover, two well-known resveratrol effectors, cyclin D1 (CCND1) and cyclin B1 (CCNB1), were also repressed at both times. Congruently, we found that resveratrol impaired G1/S phase transition in both MDA-MB-231 and MCF-7 cells. By western blot assays, we confirmed that resveratrol suppressed AURKA, CCND1 and CCNB1 at 24 and 48 h. In summary, we showed for the first time that resveratrol regulates cell cycle progression by targeting AURKA and PLK1. Our findings highlight the potential use of resveratrol as an adjuvant therapy for breast cancer.