Nahed Hussien

The full-length BRCA1-associated RING domain 1 (BARD1) gene encodes a 777-aa protein. BARD1 displays a dual role in cancer development and progression as it acts as a tumor suppressor and an oncogene. Structurally, BARD1 has homologous domains to BRCA1 that aid their heterodimer interaction to inhibit the progression of different cancers such as breast and ovarian cancers following the BRCA1-dependant pathway. In addition, BARD1 was shown to be involved in other pathways that are involved in tumor suppression (BRCA1-independent pathway) such as the TP53-dependent apoptotic signaling pathway. However, there are abundant BARD1 isoforms exist that are different from the full-length BARD1 due to nonsense and frameshift mutations, or deletions were found to be associated with susceptibility to various cancers including neuroblastoma, lung, breast, and cervical cancers. This article reviews the spectrum of BARD1 full-length genes and its different isoforms and their anticipated associated risk. Additionally, the study also highlights the role of BARD1 as an oncogene in breast cancer patients and its potential uses as a prognostic/diagnostic biomarker and as a therapeutic target for cancer susceptibility testing and treatment.

BACKGROUND: Despite the advancement in the fields of medical science and molecular biology, cancer is still the leading cause of death worldwide. Chemotherapy is a choice for treatment; however, the acquisition of chemoresistance is a major impediment for cancer management. Many mechanisms have been postulated regarding the acquisition of chemo-resistance in breast cancer and the impact on cellular signalling and the induction of apoptosis in tumour cells. The mechanism of the apoptotic mutation ofp53 and bcl-2 proteins is commonly associated with increased resistance to apoptosis and, therein, to chemotherapy.

OBJECTIVES: The current study was aimed to investigate A172 and MDA-MB-231 cancer cells'sensitivity against chemotherapeutic drugs, including cisplatin, doxorubicin, and paclitaxel with different doses. Moreover, it estimates resistance of cancer cells by evaluating Nitric Oxide Synthase (NOS) expression and evaluate its correlation with the expression profile proteins of the apoptosis regulating Bcl-2 family.

METHODS: Dose-dependent sensitivity to cisplatin, doxorubicin or paclitaxel was evaluated on spheroid cultured A172 and MDA-MB-231 cells lines, was measured by time-lapse microscopy over a 72h period. Expressions of two Nitric Oxide (NO) synthases isoforms (iNOS, eNOS), anti-apoptotic (Bcl-2, phospho-Bcl-2, Mcl-1, and Bcl-xL) and proapoptotic (BID, Bim, Bok, Bad, Puma, and Bax) were evaluated by Western blot. The effect of NO modulation on antiand pro-apoptotic molecule expression was also studied using Western blot.

RESULTS: A172 cells show more resistance to chemotherapy drugs than MDA-MB-231 cancer cells, therefore, they need higher doses for apoptosis. Resistance of gliomas might be returned to higher significant expression of endothelial eNOS expression. It was clear that there is not a significant effect of NO modulation on the expression of pro- andantiapoptotic proteins on both cell lines.

CONCLUSION: The present work provides a putative mechanism for the acquisition of drug resistance in breast cancer and glioma, which might be significant for clinical outcomes.

The low price and high contents of bioactive compounds in citrus peel increase interest in using it in various applications. Mandarin (Citrus reticluata) peel belongs to Rutaceae family and is rich with antioxidants. However, limited studies are available on toxicity of Mandarin peel oil (MPO) on human Prostate Cancer (PC3) cells. Therefore, the present study was conducted to study the cytotoxicity and genotoxicity of MPO on Human normal Fibroblast (HFB4) and PC3 cell lines. The half maximal inhibitory (IC50) and safe concentration of MPO was detected using MTT assay. Comet and DNA fragmentation assays were performed to assess apoptotic DNA damage. Also, the ROS level was evaluated and the mRNA expression level of apoptotic and antiapoptotic genes were measured using RT-PCR. Results of the cytotoxic test showed that MPO induced preferential inhibition of PC3 cells proliferation in a concentration-dependent manner with IC50 10.97 µg/ml. The time-dependent induction of DNA breaks demonstrated in PC3 cells treated with MPO safe concentration-stimulated ROS generation and apoptotic DNA damage through increased expression of tumor suppressor p53 and Bax genes and decreased expression of Bcl2 and MDM2 genes. In contrast, non-significant changes were observed in the DNA integrity, ROS levels and expressions of the tested genes in the normal HFB4 cells treated with MPO. Thus, we concluded that MPO induced preferential cytotoxic and genotoxic effects toward cancerous PC3 with no noticeable toxic effects in normal HFB4 cells and therefore further in vivo studies are recommended to test its possible use as anticancer drugs.

Worldwide, thalassemia represents one of the most common genetic disorders. There is a prevalence of Beta-thalassemia in Kingdom of Saudi Arabia (KSA), however there is a genetic counseling availability and an existence of mandatory premarital testing policy. Few studies detect molecular mutations of thalassemia genes in different KSA governates, including Makkah, Hufuf, Qatif, and Dammam but in our peer knowledge there is no reports on high altitude Taif region. The aim of the present study is to evaluate the molecular mutation analysis of β-thalassemia gene in El Taif province (as a high-altitude area) patients of KSA and to estimate the iron overload toxicity due to thalassemia syndrome on the hotspot noncoding D-loop region (hypervariable, HV2 gene fragment) of mtDNA. Blood samples were collected from total 25 β-thalassemia patients and 25 normal control that were used for HPLC, hematological analysis and different molecular evaluations. Extracted nuclear DNA from blood sample was used to detect known mutations accompanied with β-thalassemia in other countries using PCR-ARMS technique targeting IVSII-1, IVSI-5, Codon 8/9, Cd44 and Cd5 genes' mutations. Moreover, mtDNA was used to detect point of mutation of HV2 fragment in the D-loop region using PCR-SSCP and then sequencing. Results show significant increase in the level of HbA2 and decrease of HbA in comparison to control by using HPLC. PCR-ARMS reports that all β-thalassemia patients have heterozygous alleles of wild and mutated regions with nucleotide transition/transversion of IVSI-5 (AC>AG), Codon 8/9 (CT>CC), and Cd44 (GG>GA), however no point of mutation was detected in IVSII-1 (AC>AT) Cd5 (CT>CG) genes. Moreover, PCR-SSCP shows points of mutations for β-thalassemia HV2 fragment that were confirmed by sequencing in the form of base pairs deletion, insertion and transition/transversion. For the first time, the present study reports the presence of 2 bps found in HV2 region that might be specific to KSA nations and not found in other countries. In conclusion, our results were in concurrent with other studies in the presence of specific genetic mutations in β-thalassemia patients that is accompanied with points of mutations in HV2 region of high altitude Taif governate.