The role of ASXL1 mutations and ASXL1 CircRNAs in cancer.

BACKGROUND: Mutations in the Additional Sex Combs Like 1 (ASXL1) gene were first reported in myelodysplastic syndromes. Recent studies have clarified the relationship between ASXL1 mutations and the development of cancers. OBJECTIVE: This study aims to review the roles of ASXL1 and ASXL1 CircRNAs, such as epigenetic regulation, chromatin modification, and transcription factor function in malignancies. METHOD: This study is a review of articles related to the role of ASXL1 and ASXL1 CircRNAs in malignancies, retrieved from PubMed and Scopus. RESULTS: ASXL1 plays a role in malignancies and is also related to poor overall survival and cancer metastasis. ASXL1 encodes conserved and abundant Circular RNAs (circRNAs) that act as post-transcriptional regulators, regulating tumorigenesis and progression in cancer. ASXL1 circRNA was identified in the top 10% of differentially expressed circRNAs in clinically relevant tissues. Additionally, the role of ASXL1 gene circRNAs in cancer development is reviewed in this study. CONCLUSION: ASXL1 and ASXL1circRNA have dual functions in combination with different proteins, being involved in both transcriptional activation and repression in a context-dependent manner. Moreover, studies indicate these genes play an important role in epithelial-mesenchymal transition (EMT) and metastasis. Ongoing research is aimed at determining this gene family's function in biological events.

Imidazo[1,2-a]quinazolines as novel, potent EGFR-TK inhibitors: Design, synthesis, bioactivity evaluation, and in silico studies.

Tyrosine protein kinases (TKs) have been proved to play substantial roles on many cellular processes and their overexpression tend to be found in various types of cancers. Therefore, over recent decades, numerous tyrosine protein kinase inhibitors particularly epidermal growth factor receptor (EGFR) inhibitors have been introduced to treat cancer. Present study describes a novel series of imidazo[1,2-a]quinazolines 18 as potential -inhibitors. These imidazoquinazolines (18a and 18o, in particular) had great anti-proliferative activities with IC50 values in the micromolar (µM) range against PC3, HepG2, HeLa, and MDA-MB-231 comparing with Erlotinib as reference marketed drug. Further evaluations on some derivatives revealed their potential to induce apoptotic cell death and cell growth arrest at G0 phase of the cell cycle. Afterwards, the kinase assay on the most potent compounds 18a and 18o demonstrated their inhibitory potencies and selectivity toward EGFR (with EGFR-IC50 values of 82.0 µM and 12.3 µM, respectively). Additionally, western blot analysis on these compounds 18a and 18o exhibited that they inhibited the phosphorylation of EGFR and its downstream molecule extracellular signal-regulated kinase (ERK1/2). However, the level of B-Actin phosphorylation was not changed. Finally, density functional theory calculations, docking study, and independent gradient model (IGM) were performed to illustrate the structure-activity relationship (SAR) and to assess the interactions between proteins and ligands. The results of molecular docking studies had great agreement with the obtained EGFR inhibitory results through in vitro evaluations.

Thienopyrimidine-based agents bearing diphenylurea: Design, synthesis, and evaluation of antiproliferative and antiangiogenic activity.

An important role has been considered for the vascular endothelial growth factor receptor 2 (VEGFR-2) in the angiogenesis process, so that its inhibition is an important scientific way for cancer treatment. In this work, new thienopyrimidine derivatives were synthesized and evaluated. Compared with sorafenib, the majority of the target compounds had antiproliferative activity against the PC3, HepG2, MCF7, SW480, and HUVEC cell lines, especially 9h with IC50 values of 4.5-15.1 µM, confirming the noticeable cytotoxic effects on the listed cell lines (PC3, HepG2, SW480, and HUVEC). Analyses by flow cytometry on SW480 and HUVEC cells revealed that 9n, 9k, 9h, and 9q led to apoptotic cell death. The result of the chick chorioallantoic membrane assay showed that 9h effectively reduced the number of corresponding blood vessels. Finally, the inhibitory effect on VEGFR-2 phosphorylation was considered as the outcome of Western blot analysis of compound 9h.

Expression profiles and functional prediction of long non-coding RNAs LINC01133, ZEB1-AS1 and ABHD11-AS1 in the luminal subtype of breast cancer.

BACKGROUND: Luminal breast cancer (BC) is the most frequent subtype accounting for more than 70% of BC. LncRNAs, a class of non-coding RNAs with more than 200 nucleotides, are involved in a variety of cellular processes and biological functions. Abberant expression is related to the development of various cancers, such as breast cancer. LINC01133, ZEB1-AS1, and ABHD11-AS1 were reported to be dysregulated in different cancers. However, their expression level in luminal BC remains poorly known. The aim of the present study was to evaluate the potential roles of these lncRNAs in BC, especially in luminal subtypes. METHODS: A comprehensive analysis was performed using the Lnc2Cancer database to identify novel cancer-associated lncRNA candidates. After conducting a literature review, three novel lncRNAs named LINC01133, ZEB1-AS1, and ABHD11-AS1 were chosen as target genes of the present study. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to evaluate the expression level of the mentioned lncRNAs in both luminal BC tissues and cell lines. Then, the correlation of the three mentioned lncRNAs expression with clinicopathological characteristics of the patients was studied. Moreover, several datasets were used to discover the potential roles and functions of LINC01133, ZEB1-AS1 and ABHD11-AS1 in luminal subtype of BC. RESULTS: According to the qRT-PCR assay, the expression levels of LINC01133 and ZEB1-AS1 were decreased in luminal BC tissues and cell lines. On the other hand, ABHD11-AS1 was upregulated in the above-mentioned samples. The expression levels of LINC01133, ZEB1-AS1, and ABHD11-AS1 were not associated with any of the clinical features. Also, the results obtained from the bioinformatics analyses were consistent with qRT-PCR data. Functional annotation of the co-expressed genes with the target lncRNAs, protein-protein interactions and significantly enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways across luminal BC were also obtained using bioinformatics analysis. CONCLUSIONS: Taken together, our findings disclosed the dysregulation of LINC01133, ZEB1-AS1, and ABHD11-AS1 in luminal BC. It was revealed that LINC01133 and ZEB1-AS1 expression was significantly downregulated in luminal BC tissues and cell lines, while ABHD11-AS1 was upregulated considerably in the mentioned tissues and cell lines. Also, bioinformatics and systems biology analyses have helped to identify the possible role of these lncRNAs in luminal BC. However, further analysis is needed to confirm the current findings.

Mono- and bis-pyrazolophthalazines: Design, synthesis, cytotoxic activity, DNA/HSA binding and molecular docking studies.

In an attempt to find new potent cytotoxic compounds, several mono- and bis-pyrazolophthalazines 4a-m and 6a-h were synthesized through an efficient, one-pot, three- and pseudo five-component synthetic approach. All derivatives were evaluated for their in vitro cytotoxic activities against four human cancer cell lines of A549, HepG2, MCF-7, and HT29. Compound 4e showed low toxicity against normal cell lines (MRC-5 and MCF 10A, IC50 > 200 µM) and excellent cytotoxic activity against A549 cell line with IC50 value of 1.25 ± 0.19 µM, which was 1.8 times more potent than doxorubicin (IC50 = 2.31 ± 0.13 µM). In addition, compound 6c exhibited remarkable cytotoxic activity against A549 and MCF-7 cell lines (IC50 = 1.35 ± 0.12 and 0.49 ± 0.01 µM, respectively), more than two-fold higher than that of doxorubicin. The binding properties of the best active mono- and bis-pyrazolophthalazine (4e and 6c) with HSA and DNA were fully evaluated by various techniques including UV-Vis absorption, circular dichroism (CD), Zeta potential and dynamic light scattering analyses indicating interaction of the compounds with the secondary structure of HSA and significant change of DNA conformation, presumably via a groove binding mechanism. Additionally, molecular docking and site-selective binding studies confirmed the fundamental interaction of compounds 4e and 6c with base pairs of DNA. Compounds 4e and 6c showed promising features to be considered as potential lead structures for further studies in cancer therapy.

Quinazolin-4(3H)-one based agents bearing thiadiazole-urea: Synthesis and evaluation of anti-proliferative and antiangiogenic activity.

A series of quinazolin-4(3H)-one based agents containing thiadiazole-urea were designed, synthesized, and biologically evaluated. The proliferation rate of PC3 cells was moderately reduced by compound 9f (IC50 = 17.7 µM)which was comparable with sorafenib (IC50 = 17.3 µM). There was also a significant reduction in the number of HUVEC cells, when they were exposed to compound 9y (IC50 = 6.1 µM). To test the potential of compounds in inducing apoptosis, Annexin V-FITC/propidium iodide double staining assay was used. After the treatment of HUVEC cells with 9f, they underwent apoptotic effects. A substantial effort was dedicated to gathering comprehensive data across CAM assay. These data showed that 9f moderately inhibits the growth of corresponding blood vessels. Finally, the outcomes of Western blotting proposed a mechanism of action, by which the phosphorylation of VEGFR-2 is inhibited by compounds 9f and 9y.

Circular RNA; a new biomarker for breast cancer: A systematic review.

Circular RNAs (circRNAs) were recently discovered as a looped subset of competing endogenous RNAs, with an ability to regulate gene expression by microRNA sponging. There are several studies on their potential roles in cancer development, such as colorectal cancer and basal cell carcinoma. However, there is still a significant gap in the knowledge about circRNA functions in breast cancer (BC) progression. The current study systematically reviewed circRNA biogenesis and their potential roles as a novel biomarker in BC on published studies of the MEDLINE®/PubMed, Cochrane®, and Scopus® databases. The obtained results showed a general dysregulation of circRNAs expression in BC cells with a cell-type and stage-specific manner. The potential connection between circRNAs and BC cell proliferation, apoptosis, metastasis, and chemotherapy sensitivity and resistance were discussed.

Evaluation of the potential role of long non-coding RNA LINC00961 in luminal breast cancer: a case-control and systems biology study.

BACKGROUND: Luminal subtype is the most common subgroup of breast cancer (BC), accounting for more than 70% of this cancer. Long non-coding RNAs (lncRNAs) are a group of RNAs which play critical roles in diverse cellular processes. It is proved that dysregulation of them can contribute to the development of various cancers, including BC. LINC00961 was reported to be downregulated in several cancers, however, its expression level in BC remains largely unknown. The purpose of the present study was to investigate the possible role of LINC00961 in luminal A and B subtypes of BC. METHODS: To obtain novel lncRNAs associated with different cancers and differentially expressed lncRNAs (DElncRNAs) between BC tumor and normal tissues, Lnc2Cancer and GDC databases were used, respectively. After performing literature review, the expression level of the selected lncRNA (LINC00961) was evaluated in 79 luminal A and B BC specimens and adjacent non-cancerous tissues by Quantitative Reverse Transcription PCR (qRT-PCR). LINC00961 expression was also evaluated in two luminal A BC cell lines, compared to a normal breast cell line. The comparison of the differences between tumor and adjacent non-tumor samples was performed by paired sample t-test. Moreover, correlation analysis between LINC00961 expression and clinicopathological features was performed using the chi-square, fisher exact, and independent t-test. In order to investigate the possible roles of LINC00961 in luminal A and B BC, different bioinformatics analyses such as functional annotation of the LINC00961 co-expressed genes and protein-protein interaction (PPI) networks construction were also performed. RESULTS: LINC00961 was selected as a significant DElncRNA which had not been studied in BC. According to q-RT PCR assay, LINC00961 was downregulated in luminal BC tissues and cell lines. Its expression was correlated with smoking status and the age of menarche in luminal BC patients. Also, the results of the bioinformatics analysis were consistent with the data obtained from q-RT PCR assay. The final results indicated that LINC00961 might be involved in multiple cancer-associated pathways such as chemokine, Ras and PI3K-Akt signaling pathways, GPCR ligand binding, and signal transduction in luminal subtypes of BC. CDH5, GNG11, GNG8, SELL, S1PR1, CCL19, FYN, ACAN, CD3E, ACVRL1, CAV1, and PPARGC1A were identified as the top hub genes of the PPI networks across luminal subgroup. CONCLUSION: Our findings suggested that LINC00961 was significantly downregulated in luminal A and B subtypes of BC. Moreover, bioinformatics analysis provided a basis for better identification of the potential role of LINC00961 in luminal subtype of BC.

Unique CD44 intronic SNP is associated with tumor grade in breast cancer: a case control study and in silico analysis.

BACKGROUND: CD44 encoded by a single gene is a cell surface transmembrane glycoprotein. Exon 2 is one of the important exons to bind CD44 protein to hyaluronan. Experimental evidences show that hyaluronan-CD44 interaction intensifies the proliferation, migration, and invasion of breast cancer cells. Therefore, the current study aimed at investigating the association between specific polymorphisms in exon 2 and its flanking region of CD44 with predisposition to breast cancer. METHODS: In the current study, 175 Iranian female patients with breast cancer and 175 age-matched healthy controls were recruited in biobank, Breast Cancer Research Center, Tehran, Iran. Single nucleotide polymorphisms of CD44 exon 2 and its flanking were analyzed via polymerase chain reaction and gene sequencing techniques. Association between the observed variation with breast cancer risk and clinico-pathological characteristics were studied. Subsequently, bioinformatics analysis was conducted to predict potential exonic splicing enhancer (ESE) motifs changed as the result of a mutation. RESULTS: A unique polymorphism of the gene encoding CD44 was identified at position 14 nucleotide upstream of exon 2 (A37692→G) by the sequencing method. The A > G polymorphism exhibited a significant association with higher-grades of breast cancer, although no significant relation was found between this polymorphism and breast cancer risk. Finally, computational analysis revealed that the intronic mutation generated a new consensus-binding motif for the splicing factor, SC35, within intron 1. CONCLUSIONS: The current study results indicated that A > G polymorphism was associated with breast cancer development; in addition, in silico analysis with ESE finder prediction software showed that the change created a new SC35 binding site.

Study of the tumor microenvironment during breast cancer progression.

BACKGROUND: Different cells and mediators in the tumor microenvironment play important roles in the progression of breast cancer. The aim of this study was to determine the composition of the microenvironment during tumor progression in order to discover new related biomarkers and potentials for targeted therapy. METHODS: In this study, breast cancer biopsies from four different stages, and control breast biopsies were collected. Then, the mRNA expression of several markers related to different CD4+ T cell subsets including regulatory T cells (Treg), T helper (Th) type 1, 2 and 17 were determined. In addition, we investigated the expression of two inflammatory cytokines (TNF-α and IL-6) and inflammatory mediators including FASL, IDO, SOCS1, VEGF, and CCR7. RESULTS: The results showed that the expression of Th1 and Th17 genes was decreased in tumor tissues compared to control tissues. In addition, we found that the gene expression related to these two cell subsets decreased during cancer progression. Moreover, the expression level of TNF-α increased with tumor progression. CONCLUSION: We conclude that the expression of genes related to immune response and inflammation is different between tumor tissues and control tissues. In addition, this difference was perpetuated through the different stages of cancer.

Clinical significance of NDRG3 in patients with breast cancer.

AIM: The expression level of NDRG3 gene is investigated among breast cancer (BC) patients. METHODS: Real-time quantitative PCR was performed. RESULTS:  NDRG3 was downregulated in BC patients particularly in advanced stage of the disease. HER2 status was significantly correlated with the expression of NDRG3. Also, triple-negative BC patients showed low levels of NDRG3 expression in comparison to other subtypes. Lastly, the expression of NDRG3 had significant impact on survival, with NDRG3 downregulated patients having the worst event-free survival rate among others. CONCLUSION: We have presented that NDRG3 might be a tumor suppressor candidate. NDRG3 downregulation might be involved in the tumorigenesis and development of invasive BC in an advanced phase of the disease.

AKAP3 correlates with triple negative status and disease free survival in breast cancer.

BACKGROUND: Cancer-testis antigens are among the new promising biomarkers, especially for targeted therapy. Aberrant and specific expression of these proteins has been reported in some tumor tissues. Also understanding their differential role in normal and cancer tissues may introduce them as new candidates for biomarker in cancer. METHODS: AKAP3 expression was investigated in 162 tumors, normal adjacent and normal tissues of the breast with Real-Time PCR. Also the correlation between the gene expression and clinico-pathologic features of the tumors and treatment regimen was evaluated. RESULTS: There was an association between lack of AKAP3 expression in tumor tissues and triple negative status (p=. 03). There was also a correlation between lack of this marker and tumor size (p = .01) and stage (p = .04). Lack of AKAP3 in normal adjacent tissues was associated with poor prognosis. Kaplan Meier plot demonstrated a remarkable better 5-year disease free survival in AKAP3 positive normal adjacent group. CONCLUSIONS: It was found that this relationship is originated from the difference in AKAP3 expression, not therapy distribution between two groups of patients. Thus, it may be a proper biomarker candidate for triple negative breast cancer patients. Also, testing AKAP3 in normal tissue of the patients may be used to predict the outcome of the treatment.

The endogenous association among MMP2/miR-1248/Circ_0087558/miR-643/ MAP2K6 axis can contribute to brain metastasis in basal-like subtype of breast cancer.

Brain metastasis in basal-like breast cancer poses a significant challenge in cancer management due to its aggressive nature and limited treatment options. This study conducted a comprehensive analysis to explore the potential role of circular RNAs (circRNAs) as members of endogenous networks in developing breast cancer brain metastasis. Here, we utilized RNA sequencing data from primary breast cancer and brain metastasis tissue with basal-like subtype (n = 11). After quality controlling and preprocessing of fastq files, gene expression of mRNA and circRNAs were extracted from matched samples and normalized. Then, we employed the weighted gene co-expression network analysis approach to identify brain metastasis-associated circRNA modules ( S p e a r m a n Correlation > 0.5 , P - value < 0.05 ). Moreover, we found five protein-coding genes of PHLDA1, SLC12A2, MMP2, RGP1, and MAP2K6, significantly upregulated in brain metastatic tissues compared to primary breast cancer ( FDR < 0.05 ). These genes were enriched in the "GnRH signaling pathway" and "Fluid shear stress and atherosclerosis" pathways ( FDR < 0.05 ). Next, to explore the potential interactions between circRNAs and protein-coding genes, we reconstructed a competing endogenous RNA (ceRNA) network using mutual miRNAs between the circRNA module and upregulated mRNAs. Notably, we could detect two axes of circ_0087558/miR-604/MMP2 and MMP2/miR-1248/Circ_0087558/miR-643/MAP2K6 in ceRNA network. In conclusion, the identified circRNA-miRNA-mRNA axes might be therapeutic targets or diagnostic biomarkers for this challenging subtype of breast cancer. However, due to the small number of samples, further experimental validations are essential.

In-silico and in-vitro evidence suggest LINC01405 as a sponge for miR-29b and miR-497-5p, and a potential regulator of Wnt, PI3K, and TGFB signaling pathways in breast carcinoma.

BACKGROUND: Carcinoma of the breast, a prevailing factor in female mortality worldwide, involves dysregulation of lncRNAs and microRNAs. AIM: The main goal of this research was to predict and experimentally examine the LINC01405 expression status in breast cancer subtypes, along with investigation of its interaction with miR-29b and miR-497-5p that results in regulating PI3-Kinase, WNT, and TGF-beta signaling pathways. METHODS AND RESULTS: We performed a meta-analysis of five GEO datasets, encompassing microarray and RNA-seq data, to identify differentially expressed genes. The Cancer Genome Atlas transcriptome dataset was also analyzed to determine essential gene modules, associated with different stages of breast cancer by weighted gene co-expression networks. In addition, networks of drug-gene interactions were constructed to explore potential treatment options. LINC01405 as a microRNA sponge was chosen and examined. furthermore, downstream target genes were discovered. Experimental validation consisted of plasmid constructs used in cell culture experiments, RT-qPCR for expression analysis, and cell cycle assays. Our bioinformatics findings showed higher LINC01405 expression in Basal-like triple-negative breast carcinoma. In contrast, lower expression in Luminal samples was observed compared with normal samples, which was consistently observed in both breast cancer tissues and cell lines. LINC01405 expression level was correlated with miR-29b and miR-497 levels. The MDA-MB-231 cell line demonstrated higher LINC01405 expression and lower miR-29b and miR-497 expression levels. However, SKBR3 and MCF7 cells had lower LINC01405 expression and higher miR-29b and miR-497 levels, suggesting a regulatory role for LINC01405 as a competing endogenous RNA. This was experimentally confirmed when LINC01405 was overexpressed in SKBR3 cells, and the common target genes of miR-29b and miR-497 were upregulated. Additionally, LINC01405 upregulation led to the increased cell populations, proliferation, and upregulation of critical cancer-related genes, including AKT1, AKT3, mTOR, WNT3A, SMAD3, CYCLIN D1, CYCLIN D2, BCL2, and GSK3B. CONCLUSION: We revealed the differential expression of LINC01405 in several types of breast cancer and its role in regulating signaling pathways, potentially via scavenging miRNAs. These findings clarified the role of LINC01405 in breast cancer development and identified potential therapeutic targets.

Iranian Breast Cancer Bio-Bank: the activity and challenging issues.

The information gained from the Human Genome Project has facilitated molecular as well as cellular studies not only to find the origins of Breast Cancer (BC), but also to create novel, and effective treatments. In order to provide an infrastructure for local and international research in this area, Iranian Center for Breast Cancer (ICBC) has established a Bio-Bank (BB) for BC. This article describes the aim, structure, and activities in general, and the challenging issues confronting the bank as a model for the establishment of Bio-Banks in developing countries in particular. The methods employed by the Bank could be explained in the following categories: Blood and Tissue sampling, Preparation and Banking of collected Samples, Clinical and Histopathology data collection, Collaboration Protocol, Challenging issues, and the programs to confront the problems. During the five-year activity of the bank, 110 families were enrolled for genetic counseling, from whom 600 biologic samples were obtained, including 387 blood samples and 213 tissue samples. Of 387 blood samples, 317 (82%) were found to belong to the BC patients and the remaining 70 (18%) belonged to their available relatives. The number of samples increased over the study period partly as a result of the programs designed to confront the problems. During the study period, there were some finished research studies using the samples of BB, and many other studies which are still ongoing. ICBC-BB is a model of biologic sample banking which provides a significant number of biological samples for local and international collaborative research projects regarding molecular and cellular aspects of BC. In establishing the ICBC-BB we have experienced problems and challenges, some general and some local. Some were expected and others not, but we have identified solutions.

Ultrasound features of pregnancy-associated breast cancer: A retrospective observational analysis.

Pregnancy-associated breast cancer (PABC) is a poor prognosis in women, and the mortality rate is higher in this subgroup of patients than in non-PABC. This study aims to assess clinicopathological and ultrasound features of patients with PABC. Of 75 patients with breast cancer, 31 cases were in lactating, or pregnancy phase and 44 patients had no recent history of pregnancy/lactation at the time of cancer detection. The available pathological characteristics and ultrasound findings of the PABC and non-PABC groups were compared. The analysis of ultrasound findings demonstrated that the percentages of antiparallel orientation (p = 0.04) and heterogeneous internal echo pattern (p = 0.002) were higher in the PABC group. The final Breast Imaging Reporting and Data System (BI-RADS) assessment in the two groups was significantly different (p = 0.008). In this study, most PABCs were BI-RADS 4c or 5; compared with age-matched non-PABC cases. There were significant differences in ER (p = 0.03), receptor groups (p = 0.007), and tumor grade (p = 0.02) in PABC compared to non-PABC group. To conclude, radiologists should be careful about ultrasound findings of PABC and recommend core needle biopsy in suspected cases.

Inter-BRCT linker is probably the most intolerant region of the BRCA1 BRCT domain.

Pathogenic mutations in BRCA1 are associated with an increased risk of hereditary breast, ovarian, and some other cancers; however, the clinical significance of many mutations in this gene remains unknown (Variants of Unknown Significance/VUS). Since mutations in intolerant regions of a protein lead to dysfunction and pathogenicity, identifying these regions helps to predict the clinical importance of VUSs. This study aimed to identify intolerant regions of BRCA1 and understand the possible root of this susceptibility. Intolerant regions appear to carry more pathogenic mutations than expected due to their lower tolerance to missense variations. Therefore, we hypothesized that among the BRCA1 regions, the higher the mutation density, the greater the intolerance. Thus, pathogenic mutation density and regional intolerance scores were calculated to identify BRCA1-intolerant regions. To investigate the pathogenic mechanisms of missense-intolerant regions in BRCA1, transcription activation (TA) experiments and molecular dynamics (MD) simulations were also performed. The results showed that the RING domain, followed by the BRCT domain, has the highest density of pathogenic mutations. In the BRCT domain, a higher density of pathogenic mutations was observed in the inter-BRCT linker. Additionally, scores generated by Missense Tolerance Ratio-3D (MTR3D) and the Missense Tolerance Ratio consensus (MTRX) showed that the inter-BRCT linker is more intolerant than other regions of the BRCT domain. The MD results showed that mutations in the inter-BRCT linker led to cancer susceptibility, likely due to disruption of the interaction between BRCA1 and phosphopeptides. TA laboratory assays further supported the importance of the inter-BRCT linker.Communicated by Ramaswamy H. Sarma.

Recombinant anti-human epidermal growth factor receptor type 2 single-chain variable fragment-alpha-luffin fusion protein as a putative immunotoxin against human epidermal growth factor receptor type 2-positive breast cancer cells: an experimental research.

Background: Breast cancer is one of the most frequent causes of cancer death in women. The application of immunotoxins to target overexpressed biomarkers on the surface of cancer cells and delivery of the toxin molecules into these cells has attracted too much attention during the last decade. Objectives: This study was conducted to investigate the possible in-vitro cytotoxic and apoptotic activity of previously designed recombinant immunotoxin compromising anti-HER2 single-chain variable fragment (scFv) and alpha-luffin protein in human epidermal growth factor receptor type 2 (HER2)-positive and HER2-negative breast cancer cell lines. Materials and methods: The previously designed recombinant immunotoxin and alpha-luffin protein were expressed in E. coli host cells and purified using Ni-affinity chromatography. The cytotoxicity of the proteins was tested through MTT and apoptosis studies on HER2-positive and HER2-negative breast cancer cell lines. Results: Treatment of SKBR3 and MDA-MB-468 cells with the immunotoxin caused differential cytotoxicity and apoptotic events. Flow cytometry analysis indicated that the immunotoxin could arrest SKBR3 cells at the G0/G1 phase and induce apoptosis and cell death which were not observed in HER2-negative MDA-MB-468 cells. Annexin V/PI staining revealed late apoptotic events in SKBR3 cells treated with the immunotoxin which was different from the early apoptosis induced by the alpha-luffin protein alone. Conclusions: This immunotoxin could be a promising tool in developing new targeted therapeutic agents against HER2-positive cancer cells. Animal experiments are needed before making firmed conclusions.

A coumarin-based fluorescent chemosensor as a Sn indicator and a fluorescent cellular imaging agent.

In the present study, fluorogenic coumarin-based probes (1-3) through condensation of 4-hydroxy coumarin with malondialdehyde bis(diethyl acetal)/triethyl orthoformate were prepared. The absorption and fluorescence emission properties of 2b and 3 in different solvents were studied, and a considerable solvatochromic effect was observed. The sensitivity of chemosensors 2b and 3 toward various cations and anions was investigated. It was revealed that compound 3 had a distinct selectivity toward Sn2+, possibly via a chelation enhanced quenching mechanism. The fluorescence signal was quenched over the concentration range of 6.6-120 µM, with an LOD value of 3.89 µM. The cytotoxicity evaluation of 3 against breast cancer cell lines demonstrated that the chemosensor was nontoxic and could be used successfully in cellular imaging. The probe responded to tin ions not only via fluorescence quenching, but also through colorimetric signal change. The change in optical properties was observed in ambient conditions and inside living cells.

Effects of noncoding RNAs in radiotherapy response in breast cancer: a systematic review.

Radiotherapy has an essential role in breast cancer treatment. However, tumor cells may be resistant to radiotherapy. Noncoding RNAs are considered regulators of different pathways which modulate radiotherapy. This systematic review classifies long noncoding RNAs, and microRNAs precipitated in the radiation response of breast cancer patients. A total of 14 microRNAs and 8 long noncoding RNAs were studied in this review. MiR-22, miR-200 c, Let7, and LINP1 as tumor suppressors increase the effect of radiotherapy in BC. However, some noncoding RNAs such as HOTAIR, NEAT1, and miR-21 are precipitated in radio-resistance breast cancers. Significant changes in the pattern of noncoding RNAs expression before and after radiotherapy make them a good candidate for the prognosis and prediction of radiotherapy response. MiR-21 and miR-182 can promote radio-resistance via cancer stem cells. At last, the molecular mechanisms initiating radio-resistance were also examined to find the candidate noncoding RNAs for the development of radiation-sensitized agents.