The lncRNA ATB–miR-200b Axis: Drug-Specific Regulation by Doxorubicin and Paclitaxel in ER-Positive Breast Cancer

Abstract

Objective: This study aimed to examine the expression patterns of long non-coding RNA ATB and microRNA-200b (miR-200b) in MCF-7 human breast cancer cells after treatment with two commonly used chemotherapeutic agents: doxorubicin (DOX) and paclitaxel (PTX). The goal was to determine whether the ATB–miR-200b regu latory axis influences drug-specific responses. Materials and Methods: MCF-7 cells were treated with IC₅₀ concentrations of DOX and PTX for 48 h. Total RNA was extracted, and cDNA was synthesised for both lncRNA and miRNA fractions. The expression levels of ATB and miR-200b were measured using quantitative real-time PCR (RT-qPCR). GAPDH and U6 served as internal references. Relative quantification was carried out using the 2−ΔΔCt method. Results: lncRNA ATB expression was significantly decreased in both treatment groups (p < 0.05). Interestingly, miR-200b expression was decreased in PTX-treated cells but moderately increased in DOX treated cells. These results indicate a different regulatory response of the ATB–miR-200b axis depending on the chemotherapeutic agent used. Conclusion: Our findings show that ATB and miR-200b respond differently to DOX and PTX exposure in MCF-7 cells. The simulta neous decrease of ATB and miR-200b in response to PTX may indicate EMT-related resistance mechanisms, whereas the increase of miR-200b in DOX-treated cells may be linked to apoptotic activation. More research is needed to understand the role of this regulatory axis in chemotherapy response.

Keywords

• Breast cancer
• MCF-7 cell line
• lncRNA ATB
• miR-200b
• doxorubicin
• paclitaxel
• RT-qPCR

lncRNA ATB-miR200b Aksisi: ER-Pozitif Meme Kanserinde Doksorubisin ve Paklitaksel ile İlaç Spesifik Düzenlenmesi

Abstract

Amaç: Bu çalışma, sık kullanılan iki kemoterapötik ajan olan doksorubisin (DOX) ve paklitaksel (PTX) uygulaması sonrasında insan meme kanseri hücre hattı MCF-7’de uzun kodlamayan RNA ATB (lncRNA ATB) ve mikroRNA-200b (miR-200b) ekspresyon paternlerini incelemeyi amaçlamıştır. Çalışmanın bir diğer amacı, ATB–miR-200b düzenleyici aksının ilaç-spesifik yanıtları etkileyip etkilemediğini ortaya koymaktır. Gereç ve Yöntemler: MCF-7 hücreleri, DOX ve PTX’in IC₅₀ konsantrasyonlarıyla 48 saat süreyle muamele edilmiştir. Toplam RNA izole edilmiş, lncRNA ve miRNA fraksiyonları için cDNA sentezi yapılmıştır. ATB ve miR-200b ekspresyon düzeyleri kantitatif gerçek zamanlı PCR (RT-qPCR) yöntemiyle ölçülmüştür. lncRNA için GAPDH, miRNA için ise U6 referans gen olarak kullanılmıştır. Rölatif kantifikasyon 2−ΔΔCt yöntemi ile hesaplanmıştır. Bulgular: lncRNA ATB ekspresyonu her iki tedavi grubunda da anlamlı düzeyde azalmıştır (p < 0,05). İlginç şekilde, miR-200b PTX ile muamele edilen hücrelerde azalmış, DOX ile muamele edilen hücrelerde ise orta derecede artış göstermiştir. Bu sonuçlar, kullanılan kemoterapötik ajana bağlı olarak ATB–miR-200b aksının farklı düzenleyici yanıtlar verebileceğini göstermektedir. Sonuç: Bulgularımız, ATB ve miR-200b’nin MCF-7 hücrelerinde DOX ve PTX uygulamasına farklı yanıtlar verdiğini ortaya koymak tadır. PTX’e yanıt olarak hem ATB hem de miR-200b ekspresyonunun azalması, EMT (epitelyal-mezenkimal geçiş) ile ilişkili direnç mekanizmalarını düşündürmektedir. DOX uygulamasında miR-200b düzeyinin artması ise apoptoz aktivasyonu ile ilişkili olabilir. Bu düzenleyici aksın kemoterapi yanıtındaki rolünü netleştirmek için ileri çalışmalara ihtiyaç vardır.

Keywords

• Meme kanseri
• MCF-7 hücre hattı
• lncRNA ATB
• miR-200b
• Doksorubisin
• Paklitaksel
• RT-qPCR

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