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Fulltext A novel 4-arm DNA/RNA Nanoconstruct triggering Rapid Apoptosis of Triple Negative Breast Cancer Cells within 24 hours

Tung J, Tew LS, Hsu YM, Khung YL

Sci Rep, 2017 04 11;7(1):793.
PMID: 28400564 DOI: 10.1038/s41598-017-00912-3

Measuring at ~30 nm, a fully customizable holliday junction DNA nanoconstruct, was designed to simultaneously carry three unmodified SiRNA strands for apoptosis gene knockout in cancer cells without any assistance from commercial transfection kits. In brief, a holliday junction structure was intelligently designed to present one arm with a cell targeting aptamer (AS1411) while the remaining three arms to carry different SiRNA strands by means of DNA/RNA duplex for inducing apoptosis in cancer cells. By carrying the three SiRNA strands (AKT, MDM2 and Survivin) into triple negative breast MDA-MB-231 cancer cells, cell number had reduced by up to ~82% within 24 hours solely from one single administration of 32 picomoles. In the immunoblotting studies, up-elevation of phosphorylated p53 was observed for more than 8 hours while the three genes of interest were suppressed by nearly half by the 4-hour mark upon administration. Furthermore, we were able to demonstrate high cell selectivity of the nanoconstruct and did not exhibit usual morphological stress induced from liposomal-based transfection agents. To the best of the authors' knowledge, this system represents the first of its kind in current literature utilizing a short and highly customizable holliday DNA junction to carry SiRNA for apoptosis studies.

Matched MeSH terms: Triple Negative Breast Neoplasms/genetics*
Overview on Epigenetic Re-programming: A Potential Therapeutic Intervention in Triple Negative Breast Cancers

Mohamad Hanif EA, Shah SA

Asian Pac J Cancer Prev, 2018 Dec 25;19(12):3341-3351.
PMID: 30583339

Breast cancer treatments leads to variable responses. Hormonal therapy is beneficial to receptor positive breast cancer
subtypes and display better clinical outcome than triple negative breast cancers (TNBCs) with FEC (5-Fluorouracil,
Epirubicin and Cyclophosphamide) the mainstay chemotherapy regiment. Owning to their negative expressions of
estrogen (ER), progesterone (PR) and HER2 receptors, disease recurrence and metastasis befalls some patients indicating
resistance to FEC. Involvement of epigenetic silencing through DNA methylation, histone methylation, acetylation and
sumoylation may be the key player in FEC chemoresistance. Epigenetic and molecular profiling successfully classified
breast cancer subtypes, indicating potential driver mechanisms to the progression of TNBCs but functional mechanisms
behind chemoresistance of these molecular markers are not well defined. Several epigenetic inhibitors and drugs have
been used in the management of cancers but these attempts are mainly beneficial in hematopoietic cancers and not
specifically favourable in solid tumours. Hypothetically, upon administration of epigenetic drugs, recovery of tumour
suppressor genes is expected. However, high tendency of switching on global metastatic genes is predicted. Polycomb
repressive complex (PRC) such as EZH2, SETD1A, DNMT, is known to have repressive effects in gene regulation and
shown to inhibit cell proliferation and invasion in breast cancers. Individual epigenetic regulators may be an option
to improve chemo-drug delivery in cancers. This review discussed on molecular signatures of various breast cancer
subtypes and on-going attempts in understanding underlying molecular mechanisms of epigenetic regulators as well
as providing insights on possible ways to utilize epigenetic enzymes/inhibitors with responses to chemotherapeutic
drugs to re-program cellular and biological outcome in TNBCs.

Matched MeSH terms: Triple Negative Breast Neoplasms/genetics*
Dysregulation of non-histone molecule miR205 and LRG1 post-transcriptional de-regulation by SETD1A in triple negative breast cancer

Mohamad Hanif EA

Mol Biol Rep, 2019 Dec;46(6):6617-6624.
PMID: 31552595 DOI: 10.1007/s11033-019-05079-w

FEC chemo-resistance in triple negative breast cancer (TNBC) remains a challenge. Therefore it is crucial to determine the right treatment regime by understanding molecular mechanisms of driver regulators involved in the progression of TNBCs. This study aims to understand SETD1A mechanisms in TNBC development in two TNBC cell lines. SETD1A was transiently transfected in MDA-MB-468 (FEC good prognosis) and Hs578T (FEC poor prognosis). Regulation of potential targets miR205, EMT marker ZEB1 and LRG1 and proliferative marker Ki-67 were tested by RqPCR to elucidate SETD1A interactions. This study displayed significant recovery of miR205 with SETD1A depletion and reduction of ZEB1 in MDA-MB-468. However, ZEB1 remained unchanged in Hs578T indicating ZEB1 regulation may be outcompeted by other mechanisms associated with aggressive cell line characteristics and the expression of endogenous ZEB1 was relatively high in Hs578T. Elevation of LRG1 and declined Ki-67 were observed by SETD1A knocked down. Enhanced expression was observed by LRG1 in Hs578T and not in MDA-MB-468 suggesting LRG1 contributed to distinct poor FEC outcome in TNBCs. The underlying mechanism of SETD1A in miR205/ZEB1/Ki-67/LRG1 axis needs further evaluation. Whether abrogation of the pathway is indeed associated with transcriptional or post-transcriptional activation in TNBC cell lines models, clearly validation in clinical samples is warranted to achieve its prognostic and therapeutic values in TNBCs.

Matched MeSH terms: Triple Negative Breast Neoplasms/genetics*
Fulltext Genome-wide association study identifies 32 novel breast cancer susceptibility loci from overall and subtype-specific analyses

Zhang H, Ahearn TU, Lecarpentier J, Barnes D, Beesley J, Qi G, et al.

Nat Genet, 2020 06;52(6):572-581.
PMID: 32424353 DOI: 10.1038/s41588-020-0609-2

Breast cancer susceptibility variants frequently show heterogeneity in associations by tumor subtype1-3. To identify novel loci, we performed a genome-wide association study including 133,384 breast cancer cases and 113,789 controls, plus 18,908 BRCA1 mutation carriers (9,414 with breast cancer) of European ancestry, using both standard and novel methodologies that account for underlying tumor heterogeneity by estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2 status and tumor grade. We identified 32 novel susceptibility loci (P breast cancer subtypes and will inform the development of subtype-specific polygenic risk scores.

Matched MeSH terms: Triple Negative Breast Neoplasms/genetics
Single-nucleotide polymorphisms and mRNA expression of CYP1B1 influence treatment response in triple negative breast cancer patients undergoing chemotherapy

Abdul Aziz AA, Md Salleh MS, Mohamad I, Krishna Bhavaraju VM, Mazuwin Yahya M, Zakaria AD, et al.

J Genet, 2018 Dec;97(5):1185-1194.
PMID: 30555068

Triple negative breast cancer (TNBC) is typically associated with poor and interindividual variability in treatment response. Cytochrome P450 family 1 subfamily B1 (CYP1B1) is a metabolizing enzyme, involved in the biotransformation of xenobiotics and anticancer drugs. We hypothesized that, single-nucleotide polymorphisms (SNPs), CYP1B1 142 C>G, 4326 C>G and 4360 A>G, and CYP1B1 mRNA expression might be potential biomarkers for prediction of treatment response in TNBC patients. CYP1B1 SNPs genotyping (76 TNBC patients) was performed using allele-specific polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism methods and mRNA expression of CYP1B1 (41 formalin-fixed paraffin embeddedblocks) was quantified using quantitative reverse transcription PCR. Homozygous variant genotype (GG) and variant allele (G) of CYP1B1 4326C>G polymorphism showed significantly higher risk for development of resistance to chemotherapy with adjusted odds ratio (OR): 6.802 and 3.010, respectively. Whereas, CYP1B1 142 CG heterozygous genotype showed significant association with goodtreatment response with adjusted OR: 0.199. CYP1B1 142C-4326G haplotype was associated with higher risk for chemoresistance with OR: 2.579. Expression analysis revealed that the relative expression of CYP1B1 was downregulated (0.592) in cancerous tissue compared with normal adjacent tissues. When analysed for association with chemotherapy response, CYP1B1 expression was found to be significantly upregulated (3.256) in cancerous tissues of patients who did not respond as opposed to those of patients who showed response to chemotherapy. Our findings suggest that SNPs together with mRNA expression of CYP1B1 may be useful biomarkers to predict chemotherapy response in TNBC patients.

Matched MeSH terms: Triple Negative Breast Neoplasms/genetics*
Fulltext Genetic Association of CYP1B1 4326 C>G Polymorphism with Disease-Free Survival in TNBC Patients Undergoing TAC Chemotherapy Regimen

Abdul Aziz AA, Md Salleh MS, Yahya MM, Zakaria AD, Ankathil R

Asian Pac J Cancer Prev, 2021 Apr 01;22(4):1319-1324.
PMID: 33906328 DOI: 10.31557/APJCP.2021.22.4.1319

BACKGROUND: Triple negative breast cancer (TNBC) which is treated with taxane, adriamycin and cyclophosphamide (TAC) chemotherapy regimen show variation in treatment response. CYP1B1 4326 C>G polymorphism has been implicated in contributing to the differences in treatment response in various types of cancers.
AIM: The objective of the present study was to investigate whether this polymorphism modulate the risk of disease recurrence in TNBC patients undergoing TAC chemotherapy regimen.
METHODS: Blood samples of 76 immunohistochemistry confirmed TNBC patients were recruited. The genotyping of CYP1B1 4326 C>G polymorphism was carried out using PCR-RFLP technique. The genotype patterns were categorized into homozygous wildtype, heterozygous and homozygous variant. Kaplan-Meier analysis followed by Cox proportional hazard regression model were performed to evaluate the TNBC patients' recurrence risk.
RESULTS: Out of 76 TNBC patients, 25 (33.0%) showed disease recurrence after one-year evaluation. Kaplan Meier analysis showed that TNBC patients who are carriers of CYP1B1 4326 GG variant genotypes (37.0%) had a significantly lower probability of disease-free rates as compared to TNBC patients who are carriers of CYP1B1 4326 CC/CG genotypes (71.0%). Univariate and multivariate Cox analysis demonstrated that TNBC patients who carried CYP1B1 4326 GG variant genotype had a significantly higher risk of recurrence with HR: 2.50 and HR: 4.18 respectively, even after adjustment as compared to TNBC patients who were carriers of CYP1B1 4326 CC and CG genotypes.
CONCLUSION: Our results demonstrate the potential use of CYP1B1 4325 GG variant genotype as a candidate biomarker in predicting risk of recurrence in TNBC patients undergoing TAC chemotherapy regimen.

Matched MeSH terms: Triple Negative Breast Neoplasms/genetics*