Circulating Small EVs miRNAs as Predictors of Pathological Response to Neo-Adjuvant Therapy in Breast Cancer Patients.

Neo-adjuvant therapy (NAT) is increasingly used in the clinic for the treatment of breast cancer (BC). Pathological response to NAT has been associated with improved patients' survival; however, the current techniques employed for assessing the tumor response have significant limitations. Small EVs (sEVs)-encapsulated miRNAs have emerged as promising new biomarkers for diagnosis and prediction. Therefore, our study aims to explore the predictive value of these miRNAs for the pathological response to NAT in BC. By employing bioinformatic tools, we selected a set of miRNAs and evaluated their expression in plasma sEVs and BC biopsies. Twelve miRNAs were identified in sEVs, of which, miR-21-5p, 221-3p, 146a-5p and 26a-5p were significantly associated with the Miller-Payne (MP) pathological response to NAT. Moreover, miR-21-5p, 146a-5p, 26a-5p and miR-24-3p were independent as predictors of MP response to NAT. However, the expression of these miRNAs showed no correlation between sEVs and tissue samples, indicating that the mechanisms of miRNA sorting into sEVs still needs to be elucidated. Functional analysis of miRNA target genes and drug interactions revealed that candidate miRNAs and their targets, can be regulated by different NAT regimens. This evidence supports their role in governing the patients' therapy response and highlights their potential use as prediction biomarkers.

Breast Cancer-Delivered Exosomal miRNA as Liquid Biopsy Biomarkers for Metastasis Prediction: A Focus on Translational Research with Clinical Applicability.

Metastasis represents the most important cause of breast cancer-associated mortality. Even for early diagnosed stages, the risk of metastasis is significantly high and predicts a grim outcome for the patient. Nowadays, efforts are made for identifying blood-based biomarkers that could reliably distinguish patients with highly metastatic cancers in order to ensure a closer follow-up and a more personalized therapeutic method. Exosomes are nano vesicles secreted by cancer cells that can transport miRNAs, proteins, and other molecules and deliver them to recipient cells all over the body. Through this transfer, cancer cells modulate their microenvironment and facilitate the formation of the pre-metastatic niche, leading to sustained progression. Exosomal miRNAs have been extensively studied due to their promising potential as prognosis biomarkers for metastatic breast cancer. In this review, we tried to depict an overview of the existing literature regarding exosomal miRNAs that are already validated as potential biomarkers, and which could be immediately available for the clinic. Moreover, in the last section, we highlighted several miRNAs that have proven their function in preclinical studies and could be considered for clinical validation. Considering the lack of standard methods for evaluating exosomal miRNA, we also discussed the challenges and the technical aspects underlying this issue.

New perspectives in triple-negative breast cancer therapy based on treatments with TGFß1 siRNA and doxorubicin.

Triple-negative breast cancer (TNBC), which accounts for 10-20% of all breast cancers, has the worst prognosis. Although chemotherapy treatment is a standard for TNBC, it lacks a specific target. Therefore, new therapeutic strategies are required to be investigated. In this study, a combined doxorubicin (DOX) and small interfering RNA (siRNA) therapy is proposed as therapeutic strategy for targeting TGFß1 gene. Hs578T cell line is used as in vitro model for TNBC, wherein TGFß1siRNA therapy is employed to enhance therapeutic effects. Cell proliferation rate is measured using an MTT test, and morphological alterations are assed using microscopically approached, while gene expression is determined by qRT-PCR analysis. The combined treatment of TGFß1siRNA and DOX reduced levels of cell proliferation and mitochondrial activity and promoted the alteration of cell morphology (dark-field microscopy). DOX treatment caused downregulation of six genes and upregulation of another six genes. The combined effects of DOX and TGFß1siRNA resulted in upregulation of 13 genes and downregulation of four genes. Silencing of TGFß1 resulted in activation of cell death mechanisms in Hs578T cells, to potentiate the effects of DOX, but not in an additive manner, due to the activation of genes involved in resistance to therapy (ABCB1 and IL-6).

Aberrant miRNAs expressed in HER-2 negative breast cancers patient.

BACKGROUND: Breast cancer is a highly heterogeneous pathology, exhibiting a number of subtypes commonly associated with a poor outcome. Due to their high stability, microRNAs are often regarded as non-invasive cancer biomarkers, having an expression pattern specific for their 'cell of origin'. METHOD: Triple negative breast cancer (TNBC: ER-, PR-, Her-2-) and double positive breast cancer (DPBC: ER+, PR+, Her-2) miRNA expression patterns were obtained by analysis of the TCGA (The Cancer Genome Atlas) data, followed by PCR-array analysis on plasma samples from 20 TNBC patients, 14 DPBC patients and 11 controls. RESULTS: Three downregulated and nine upregulated miRNAs were obtained from the TNBC analysis. Five overexpressed miRNAs were identified in the DPBC group. Four of the dysregulated miRNAs (miR-10a, miR-125b, miR-210 and miR-489) were common for both groups. The cluster miR-17-92 (miR-17, miR-20a, miR-20b, and miR-93), along with miR-130, miR-22 and miR-29a/c, were found to differentiate between TNBC and DPBC. A panel of five transcripts (miR-10a, miR-125, miR-193b, miR-200b and miR-489) was validated in a new set of plasma samples. The overlapping of TCGA and plasma profiling data revealed miR-200b, miR-200c, miR-210 and miR-29c as common signature. MiR-200b was validated on additional normal and tumor tissue samples. The expression level of this transcript from the TCGA data was correlated with lung and bone metastatic genes. CONCLUSION: The miR-200b presents a great potential for the future advancements in the diagnostic/prognostic and therapeutic approach of TNBC, along with other coding or non-coding transcripts. However, this needs to be further integrated in a regulatory network that acts in conjunction with other markers that affect the patients' prognosis or response to therapy.

OncomiR-10b hijacks the small molecule inhibitor linifanib in human cancers.

The pervasive role of microRNAs (miRNAs) in cancer pathobiology drives the introduction of new drug development approaches such as miRNA inhibition. In order to advance miRNA-therapeutics, meticulous screening strategies addressing specific tumor targets are needed. Small molecule inhibitors represent an attractive goal for these strategies. In this study, we devised a strategy to screen for small molecule inhibitors that specifically inhibit, directly or indirectly, miR-10b (SMIRs) which is overexpressed in metastatic tumors. We found that the multi-tyrosine kinase inhibitor linifanib could significantly inhibit miR-10b and reverse its oncogenic function in breast cancer and liver cancer both in vitro and in vivo. In addition, we showed that the efficacy of linifanib to inhibit tyrosine kinases was reduced by high miR-10b levels. When the level of miR-10b is high, it can "hijack" the linifanib and reduce its kinase inhibitory effects in cancer resulting in reduced anti-tumor efficacy. In conclusion, our study describes an effective strategy to screen for small molecule inhibitors of miRNAs. We further propose that miR-10b expression levels, due to the newly described "hijacking" effect, may be used as a biomarker to select patients for linifanib treatment.

Premature senescence activation in DLD-1 colorectal cancer cells through adjuvant therapy to induce a miRNA profile modulating cellular death.

Cancer, and particularly colon cancer, is associated with an increasing number of cases resistant to chemotherapy. One approach to overcome this, and to improve the prognosis and outcome of patients, is the use of adjuvant therapy alongside the standard chemotherapy regiment. In the present study, the effect of deuterium-depleted water (DDW) as a potential modulator of adjuvant therapy on DLD-1 colorectal cancer models was assessed. A number of functionality assays were performed, including MTT, apoptosis and autophagy, and mitochondrial activity and senescence assays, in addition to assessing the capacity to modify the pattern of released miRNA via microarray technology. No significant effect on cell viability was identified, but an increase in mitochondrial activity and a weak pro-apoptotic effect were observed in the treated DLD-1 cells cultured in DDW-prepared medium compared with those grown in standard conditions (SC). Furthermore, the findings revealed the capacity of DDW medium to promote senescence to a higher degree compared with SC. The exosome-released miRNA pattern was significantly modified for the cells maintained in DDW compared with those maintained in SC. These findings suggest that DDW may serve as an adjuvant treatment; however, a better understanding of the underlying molecular mechanism of action will be useful for developing novel and efficient therapeutic strategies, in which the transcriptomic pattern serves an important role.

A miRNAs profile evolution of triple negative breast cancer cells in the presence of a possible adjuvant therapy and senescence inducer.

PURPOSE: Breast cancer is a highly heterogeneous disease with an increasing number of cases resistant to chemotherapy. To increase the response to therapy, different adjuvant systems are tested, like the case of deuterium-depleted water (DDW). METHODS: For this study, we selected as in vitro model the triple-negative breast cancer cell line MDA-MB-231 and we performed a series of microscopy-based functional tests (apoptosis, autophagy assays, senescence detection) and microarray evaluation of the miRNA profile in order to evaluate changes induced by cisplatin and DDW treatment at cellular and molecular level. RESULTS: Cisplatin treatment led to increased mitochondrial activity and autophagy for cells kept in DDW, compared with those in standard conditions (SC). We also observed that cells treated with DDW medium promoted senescence in a higher level than SC. The exosomal miRNAs released in cell culture revealed an altered pattern in the case of cells maintained in DDW compared to SC. CONCLUSION: DDW was proved to be non-toxic, and, when administered with cisplatin, to slightly increase the senescence of cancer cells, therefore, can be pondered as adjuvant therapeutic agent. However, future studies are needed to be done in order to further elucidate its mechanism of action.

SChitosan-capped gold nanoparticles impair radioresistant glioblastoma stem-like cells.

PURPOSE: Glioblastoma is a rapidly evolving lethal disease mainly due to its highly chemo- and radioresistant glioblastoma stem cells (GSCs). Herein, we tested if chitosan-capped gold nanoparticles (Chit-GNPs) may overcome the limitations of drug concentrations by increased cell internalization in GSCs and if such GNPs could enhance the response to irradiation. METHODS: Chitosan was used for Chit-GNP synthesis as a reducing and stabilizing agent. Chit-GNPs were characterized by spectroscopy, dark field, transmission electron microscopy and zeta potential measurements. Patient-derived GSCs and human osteoblasts were treated with increasing concentrations of nanoparticles and irradiated. The uptake and cytotoxicity of Chit-GNPs were compared to that of uncoated GNPs. RESULTS: The positively-charged, 26 nm-sized, spherical Chit-GNPs, showed a huge intracellular accumulation into the cytosol, lysosomes and near the nucleus, whereas no uncoated GNPs were internalized within GSCs. Surprisingly, Chit-GNPs were highly cytotoxic for GSCs irrespective of cell irradiation, that failed to add an additional benefit when combined with Chit-GNPs/GNPs. Moreover, Chit-GNPs were selectively cytotoxic for GSCs and did not affect the normal cells, despite an increased nanoparticle internalization. CONCLUSIONS: The important Chit-GNP internalization and their selective cytotoxicity for GSCs make this compound a potential novel anticancer agent and a promising backbone for drug delivery in glioblastoma.

Cancer-associated rs6983267 SNP and its accompanying long noncoding RNA CCAT2 induce myeloid malignancies via unique SNP-specific RNA mutations.

The cancer-risk-associated rs6983267 single nucleotide polymorphism (SNP) and the accompanying long noncoding RNA CCAT2 in the highly amplified 8q24.21 region have been implicated in cancer predisposition, although causality has not been established. Here, using allele-specific CCAT2 transgenic mice, we demonstrate that CCAT2 overexpression leads to spontaneous myeloid malignancies. We further identified that CCAT2 is overexpressed in bone marrow and peripheral blood of myelodysplastic/myeloproliferative neoplasms (MDS/MPN) patients. CCAT2 induces global deregulation of gene expression by down-regulating EZH2 in vitro and in vivo in an allele-specific manner. We also identified a novel non-APOBEC, non-ADAR, RNA editing at the SNP locus in MDS/MPN patients and CCAT2-transgenic mice. The RNA transcribed from the SNP locus in malignant hematopoietic cells have different allelic composition from the corresponding genomic DNA, a phenomenon rarely observed in normal cells. Our findings provide fundamental insights into the functional role of rs6983267 SNP and CCAT2 in myeloid malignancies.

Genetic alterations in sporadic triple negative breast cancer.

BACKGROUND: Recent studies have aimed to identify gene mutation profiles to explain the cause of TNBC therapy limitations. METHODS: The purpose of our study was to use Next Generation Sequencing (NGS) of 46 genes with a well-defined role in cancer in a cohort of TNBC patients in order to identify novel markers that could lead to the development of strategic, adjuvant, gene-targeted therapies. RESULTS: A total of 118 gene mutations in 35 genes, 75 mutations in BRCA1 and 92 mutations in BRCA2 were identified. The clinical assessment of the identified mutations showed 27 to be possibly damaging and 59 to be damaging. TP53, KDR, PIK3CA (rs3729687), ATM, AKT1 and KIT were among the most frequently mutated genes in our TNBC cohort. The SNP AKT1 (rs3730358) was suggested to modify the risk of breast cancer. SNP PIK3CA (rs3729687) is a damaging mutation that we found to be correlated with the prognosis of TNBC. The survival curve analysis showed that the presence of AKT1, TP53, KDR, KIT, BRCA1 and BRCA2 mutations is correlated with a poor prognosis. CONCLUSION: We show a strong association between TNBC and mutations in BRCA1/2 genes and the poor outcome of these patients. Moreover, we identified several other unknown mutations putatively associated with the poor prognosis of TNBC tumors. We also discovered novel mutations never before associated with breast cancer that could putatively account for the poor prognosis of the TNBC tumors.

Double gene siRNA knockdown of mutant p53 and TNF induces apoptosis in triple-negative breast cancer cells.

Apoptosis is the major downregulated pathway in cancer. Simultaneous inhibition using specific small interfering RNA (siRNA) of two key player genes, p53 and TNF, is an interesting and feasible strategy when it comes to investigating various molecular pathways and biological processes in triple-negative breast cancer (TNBC), which is one of the most aggressive and therapeutically unresponsive forms of breast cancers. Our present research focuses on evaluating the impact of double p53-siRNA and TNF-siRNA knockdown at a cellular level, and also evaluating cell proliferation, apoptosis, induction of autophagy, and gene expression by using reverse transcription polymerase chain reaction array approaches. Simultaneous inhibition of p53 and TNF in Hs578T TNBC human cell line revealed a panel of up- and downregulated genes involved in apoptosis. Furthermore, the effects of double gene knockdown were validated in a second TNBC cell line, MDA-MB-231, by using reverse transcription polymerase chain reaction TaqMan assay. All our findings help in understanding the functional mechanisms of extrinsic apoptosis, cell signaling pathways, and the mechanisms involved in tumor cell survival, growth, and death in TNBC.

Knocking down of p53 triggers apoptosis and autophagy, concomitantly with inhibition of migration on SSC-4 oral squamous carcinoma cells.

Oral squamous cell carcinoma (OSCC) is a malignancy with elevated prevalence and somber prognosis due to the fact that most of the patients are diagnosed at an advanced stage. p53 has a crucial role in proliferation and apoptosis during the occurrence and development of numerous malignant tumors. The impact of mutated p53 on the development and progression of OSCC is unclear and might have therapeutic implications. Using an in vitro RNA interference experiment, we have evaluated the impact of p53 knockdown on cell viability, apoptosis, migration, and gene expression for key genes involved in apoptosis and angiogenesis. We observed that inhibiting the expression of p53 decreased the proliferation ability and induced apoptosis/autophagy in SSC-4 cells. Moreover, we observed that this has decreased migration and has blocked the expression of VEGF. In conclusion, our research provides a proof that a direct connection between p53 knockdown and OSCC cell death can be established, therefore opening new potential directions in OSCC molecular therapeutics and management.

HLA Genotyping using Next Generation Sequencing.

From an oncological perspective, the second most common malignancies in children are brain tumors. Despite the recent therapeutic breakthroughs in this field, concerning surgery, radiotherapy and chemotherapy alike, some cases still have poor outcomes in curability. This is especially the case in patients with high-risk histological types of tumors, and those suffering from residual, remitting and disseminated diseases. Due to the unique neuroanatomical emplacement of brain tumors and their aggressive infiltrative behavior, their total removal remains a demanding task. This can be perceived in the high rates of failure treatment and disease recurrence. Furthermore, the adjacent healthy brain tissue is inevitably damaged in the surgical process of effectively removing these tumors. Thus, stem cell transplantation may be a viable solution for the clinical management of these malignancies, as proven by various recent breakthroughs. In the current concise review, we present the role of next generation sequencing in HLA typing for stem cell transplantation in primary CNS pediatric malignancies.

Normalization of gene expression measurement of tissue samples obtained by transurethral resection of bladder tumors.

BACKGROUND: Sample processing is a crucial step for all types of genomic studies. A major challenge for researchers is to understand and predict how RNA quality affects the identification of transcriptional differences (by introducing either false-positive or false-negative errors). Nanotechnologies help improve the quality and quantity control for gene expression studies. PATIENTS AND METHODS: The study was performed on 14 tumor and matched normal pairs of tissue from patients with bladder urothelial carcinomas. We assessed the RNA quantity by using the NanoDrop spectrophotometer and the quality by nano-microfluidic capillary electrophoresis technology provided by Agilent 2100 Bioanalyzer. We evaluated the amplification status of three housekeeping genes and one small nuclear RNA gene using the ViiA 7 platform, with specific primers. RESULTS: Every step of the sample handling protocol, which begins with sample harvest and ends with the data analysis, is of utmost importance due to the fact that it is time consuming, labor intensive, and highly expensive. High temperature of the surgical procedure does not affect the small nucleic acid sequences in comparison with the mRNA. CONCLUSION: Gene expression is clearly affected by the RNA quality, but less affected in the case of small nuclear RNAs. We proved that the high-temperature, highly invasive transurethral resection of bladder tumor procedure damages the tissue and affects the integrity of the RNA from biological specimens.

MicroRNAs as regulators of apoptosis mechanisms in cancer.

MicroRNAs or miRNAs are small non-coding RNAs that regulate gene expression. Their discovery has brought new knowledge in biological processes of cancer. Involvement of miRNAs in cancer development includes several major pathways from cell transformation to tumor cell development, metastasis and resistance to treatment. The first part of this review discusses miRNAs function in the intrinsic and extrinsic pathways of apoptosis. Due to the fact that many miRNAs that regulate apoptosis have been shown to play a major role in tumor cell resistance to treatment, in the second part of the review we aim at discussing miRNAs potential in becoming curative molecules.

Caffeic acid phenethyl ester activates pro-apoptotic and epithelial-mesenchymal transition-related genes in ovarian cancer cells A2780 and A2780cis.

Ovarian cancer is a highly aggressive pathology, displaying a poor prognosis and chemoresistance to classical therapy. The present study was conducted to evaluate the effect of caffeic acid phenethyl ester (CAPE) on survival of ovarian cancer cell lines, A2780 (sensitive to cisplatin) and A2780cis (resistant to cisplatin). MTT assay was used to evaluate cell viability, while the apoptotic processes were examined by flow cytometry and qRT-PCR. A reduction of cell proliferation and activation of the apoptosis was observed in both cell lines. qRT-PCR evaluation demonstrated the activation of the pro-apoptotic genes (BAD, CASP8, FAS, FADD, p53) in both cell lines. The limited therapeutic effect in A2780 cells is explained by the activation of epithelial-mesenchymal transition-related genes (ZEB1, ZEB2, or TGFBB1) as displayed by Ingenuity Network analysis. Overall data suggest that CAPE can be used as an alternative in sensitizing cells to chemotherapy.

The clinical and biological significance of MIR-224 expression in colorectal cancer metastasis.

OBJECTIVE: MicroRNA (miRNA) expression profile can be used as prognostic marker for human cancers. We aim to explore the significance of miRNAs in colorectal cancer (CRC) metastasis. DESIGN: We performed miRNA microarrays using primary CRC tissues from patients with and without metastasis, and validated selected candidates in 85 CRC samples by quantitative real-time PCR (qRT-PCR). We tested metastatic activity of selected miRNAs and identified miRNA targets by prediction algorithms, qRT-PCR, western blot and luciferase assays. Clinical outcomes were analysed in six sets of CRC cases (n=449), including The Cancer Genome Atlas (TCGA) consortium and correlated with miR-224 status. We used the Kaplan-Meier method and log-rank test to assess the difference in survival between patients with low or high levels of miR-224 expression. RESULTS: MiR-224 expression increases consistently with tumour burden and microsatellite stable status, and miR-224 enhances CRC metastasis in vitro and in vivo. We identified SMAD4 as a miR-224 target and observed negative correlation (Spearman Rs=-0.44, p<0.0001) between SMAD4 and miR-224 expression in clinical samples. Patients with high miR-224 levels display shorter overall survival in multiple CRC cohorts (p=0.0259, 0.0137, 0.0207, 0.0181, 0.0331 and 0.0037, respectively), and shorter metastasis-free survival (HR 6.51, 95% CI 1.97 to 21.51, p=0.0008). In the TCGA set, combined analysis of miR-224 with SMAD4 expression enhanced correlation with survival (HR 4.12, 95% CI 1.1 to 15.41, p=0.0175). CONCLUSIONS: MiR-224 promotes CRC metastasis, at least in part, through the regulation of SMAD4. MiR-224 expression in primary CRC, alone or combined with its targets, may have prognostic value for survival of patients with CRC.

Exosome-Carried microRNA-375 Inhibits Cell Progression and Dissemination via Bcl-2 Blocking in Colon Cancer.

BACKGROUND AND AIMS: Worldwide, colorectal cancer (CRC) is the third most common cancer in men and second in women. The aim of the current study was to identify whether the miR-375 is indeed down-regulated in metastatic CRC and if it could be considered as a potential minimally invasive prognostic biomarker for CRC. METHODS: Exosomes were isolated and characterized from patients with liver metastasis from CCR. The characterization of exosome was performed using TEM/SEM. HCT116 cells were treated with miR-375 mimic, NSM and miR-375 inhibitor. Functional assays included cell counting assay for 14 days, Matrigel invasion assay, apoptosis assay by flow cytometry using Annexin V-FITC, RT-PCR and Western blotting. RESULTS: Increased proliferation potential was proven for the cells transfected with miR-375 inhibitor, while the miR-375 mimic decreased the cell number. The cells transfected with the miR-375 inhibitor are aggressive and cross the membrane; 3.84% of the cells transfected with the miR-375 inhibitor entered apoptosis, while 6.45% of those transfected with the non-specific mimic were in programmed cell death, less than those transfected with the microRNA. RT-PCR for Bcl-2 expression showed that Bcl-2 is down-regulated for miR-375 inhibitor and up-regulated for the miR-375 mimic, a result confirmed by Western blotting. CONCLUSION: The present study brings to the forefront new data that suggest miR-375 as a new player in controlling the pathways responsible for inhibiting the natural history of CRC tumor cells, via the Bcl-2 pathway.

p53 siRNA - a therapeutic tool with significant implication in the modulation of apoptosis and angiogenic pathways.

BACKGROUND AND AIMS: siRNAs represent an encouraging novel alternative in cancer therapy as a result of targeting the mutated tumour suppressor genes or activated oncogenes. Targeting oncogenic signals, as the mutated p53 gene that gains oncogenic role, we observed inhibition of migration, a downregulation of specific genes involved in apoptosis but also in angiogenesis, connected with a reduction in invasion rate in the case of p53siRNA therapy. METHODS: The study was designed to assess the role of p53 by using RNAi (RNA interference) in Hela in vitro cell culture model. Therefore cell migration rate was assessed by using xCELLigence Systems, gene expression for a panel of genes involved in apoptosis and angiogenesis, and validation of gene expression data at protein level. RESULTS: On the selected in vitro model p53 siRNA therapy was correlated with the reduction of cell migration. The downregulation of p53, PTEN, TNFα, NFkB, BCL-2, ICAM-2, VEGF, and FGFb was evidenced as response to p53 inhibition. CONCLUSION: RNAi may be a valuable technology in order to restore the normal cellular phenotype. The results in the current research may also have an important significance outside the context of cervical cancer, by using specific inhibitors for p53 for increasing the therapeutic response in a wide range of tumoral pathology.