HDAC2 and PCNA expression is correlated to decreasing of endoxifen sensitivity in human breast cancer stem cells ALDH+
Authors: Dewi Syarifah , Sadikin Mohamad , Ramli Muchlis , Wanandi Septelia Inawati 
Published: March 2020

Latar belakang: Sel punca kanker payudara (breast cancer stem cells/BCSC) adalah subpopulasi sel kanker yang memiliki kemampuan menghasilkan tumor baru dan bersifat seperti sel punca. Penelitian kami sebelumnya menggunakan jaringan kanker payudara mengungkapkan bahwa ekspresi gen histone deacetylase 2 (HDAC2) dan proliferating cell nuclear antigen (PCNA) ditemukan perbedaan signifikan setelah terapi neoajuvan hormon dan kemoterapi. Penelitian ini bertujuan untuk menganalisis hubungan antara ekspresi HDAC2 dan PCNA dengan kelangsungan hidup sel punca kanker payudara dengan penanda aldehyde dehydrogenase + (ALDH+) yang diberi perlakuan endoksifen.
Metode: Sampel adalah BCSC primer manusia ALDH+ yang diberi perlakuan endoksifen 4 uM masingmasing selama 2, 4, 6, 8, 10, 12, 14 hari. Viabilitas sel dilihat dengan menggunakan trypan blue dan ekspresi mRNA HDAC2 dan PCNA ditentukan menggunakan qRT-PCR.
Hasil: Viabilitas BCSCs ALDH + menurun setelah 2 sampai 4 hari pemberian endoksifen. Pada periode ini juga didapatkan ekspresi mRNA HDAC2 dan PCNA mengalami penurunan. Tetapi setelah pemberian endoksifen selama 8 hari, viabilitas BCSCs ALDH + mengalami peningkatan dan ditemukan peningkatan yang signifikan pada hari ke-14 pemberian endoksifen. Ekspresi mRNA HDAC2 dan PCNA juga menunjukkan peningkatan mulai pada hari ke-8 dan terus meningkat hingga hari ke-14 pemberian endoksifen. Penelitian ini menunjukkan pola yang sama antara ekspresi mRNA HDAC2 dan PCNA dan viabilitas sel.
Kesimpulan: Induksi endoksifen yang lama menurunkan sensitivitas efek endoksifen pada BCSC manusia dan ekspresi HDAC2 dan PCNA berkorelasi dengan viabilitas BCSC manusia setelah induksi endoksifen. (Health Science Journal of Indonesia 2019;10(2):77-81)
Kata kunci: sel punca kanker payudara, viabilitas sel, HDAC2, PCNA, endoksifen

Abstract
Background: Breast cancer stem cells (BCSCs) are subpopulation of cancer cells that has the ability to generate new tumor and similar properties to stem cell. Our previous study using breast cancer patients revealed that gene expression of histone deacetylase 2 (HDAC2) and proliferating cell nuclear antigen (PCNA) were significantly altered after neoadjuvant hormone and chemotherapy. This study aimed to analyze the correlation between HDAC2 and PCNA expressions with the viability of breast cancer stem cells aldehyde dehydrogenase + (BCSC ALDH+) treated by endoxifen.
Method: Samples are human primary BCSCs ALDH+ that treated with 4 uM of endoxifen for 2, 4, 6, 8, 10, 12, 14 days, respectively. Cell viability was measured using trypan blue exclusion assay and the mRNA expressions of HDAC2 and PCNA were determined using qRT-PCR.
Results: The viability of BCSCs ALDH+ was decreased after 2 days until 4 days-endoxifen treatment. It also demonstrated that mRNA expression of HDAC2 and PCNA were decreased in this period. But after 8 days endoxifen treatment, the viability of BCSCs ALDH+ was increased. The increasing of viability was higher in 14 days-endoxifen treatment. The mRNA expression of HDAC2 and PCNA also showed increasing begin on 8 days and continued to increase until 14-days endoxifen treatment. We found a similar pattern between HDAC2 and PCNA expression and cell viability.
Conclusion: Prolonge endoxifen treatment decrease sensitivity of endoxifen effect in human BCSC and the expression of HDAC2 and PCNA are correlated to human BCSCs viability after endoxifen treatment. (Health Science Journal of Indonesia 2019;10(2):77-81)
Keywords: human breast cancer stem cells, viability, HDAC2, PCNA, endoxifen