Tumor-Promoting Effects of YAP1 and YAP S127A Overexpression in Prostate Cancer Cells

Öz

Understanding the molecular pathogenesis in cancer is crucial to shed light on novel anti-cancer treatments. YAP1 is important player in Hippo pathway to mediate tissue homeostasis. Aberrant activation of YAP1 has a role in cancer progression. This study aimed to understand the effect of overexpression of YAP1 and non-phosphorylated YAP S127A in prostate cancer progression. After transient overexpression of YAP1 and YAP S127A, the functional assays such as viability, 2D colony formation and soft agar colony formation were applied in LNCaP and PC3 cell lines. Additionally, subcellular localization of overexpressed YAP1 and YAP S127A was investigated. The cell viability was enhanced both in LNCaP and PC3 prostate cancer cell lines upon YAP S127A overexpression, with an increase of 33% in LNCaP and 25% in PC3 cells compared to control . 2D colony formation ability of PC3 cells were elevated in YAP S127A expressing cells compared to both YAP1 expressing cells (p = .037) and controls (p=.0003). The overexpressed YAP1 and YAP S127A were mainly localized to the cytoplasm. Although, the nuclear localization of overexpressed YAP1 and YAP S127A was limited, increased expression of them enhanced tumor promoting functions such as viability and 2D colony formation ability. Notably, these predominantly cytoplasmic YAP1 and YAP S127A despite the S127A mutation's design to resist phosphorylation and promote nuclear accumulation, suggest the presence of alternative regulatory mechanisms. Our results show that YAP1 may play a role in prostate cancer progression. Additional in vitro studies with more prostate cancer models and in vivo experiments are required to understand the biological impact of its cytoplasmic localization.

Anahtar Kelimeler

• prostatic neoplasms
• cell proliferation
• hippo signaling pathway
• YAP1

Prostat Kanseri Hücrelerinde YAP1 ve YAP S127A Aşırı Ekspresyonunun Tümör Artırıcı Etkileri

Öz

Kanserin moleküler patogenezini anlamak, yeni anti-kanser tedavilerine ışık tutmak açısından kritik öneme sahiptir. YAP1, Hippo sinyal yolağında doku homeostazını düzenleyen önemli bir bileşendir. YAP1'in anormal aktivasyonu, kanser ilerlemesinde rol oynar. Bu çalışma, YAP1’in ve fosforile olmayan YAP S127A'nın aşırı ifadesinin prostat kanserinin gelişimindeki etkisini anlamayı amaçlamaktadır. YAP1 ve YAP S127A'nın ekzojen ifadesinin ardından, LNCaP ve PC3 hücre hatlarında canlılık, 2D koloni oluşumu ve yumuşak agar koloni oluşumu gibi fonksiyonel analizler uygulandı. Ek olarak, YAP1'in aşırı ifade sonrası hücre içi lokalizasyonu incelendi. YAP S127A aşırı eksprese edildiğinde hücre canlılığı, LNCaP ve PC3 prostat kanseri hücre hatlarında kontrole kıyasla sırasıyla %33 ve %25 oranında artış göstermiştir. PC3 hücrelerinin 2D koloni oluşturma yeteneği; YAP S127A ifade eden hücrelerde, hem YAP1’i ifade eden hücrelere (p=.037) hem de kontrol grubuna (p=.0003) kıyasla daha yüksektir. Aşırı ifade edilen YAP1 ve YAP S127A çoğunlukla sitoplazmada lokalize olmuştur. Bununla birlikte, aşırı ifade edilen YAP1 ve YAP S127A'nın nükleer lokalizasyonu sınırlı olsa da, bu proteinlerin artan ifadesi, hücre canlılığı ve 2D koloni oluşturma yeteneği gibi tümörü destekleyici fonksiyonları güçlendirmiştir. Hem YAP1 hem de YAP S127A, S127A mutasyonunun fosforilasyona dirençli olması ve nükleer birikimi artırması için tasarlanmasına rağmen ağırlıklı olarak sitoplazmada lokalize olmuş olup, bu durum alternatif düzenleyici mekanizmaların varlığını düşündürmektedir. Sonuçlarımız YAP1'in prostat kanseri ilerlemesindeki rolünün önemli göstergeleridir. YAP1'in sitoplazmadaki rolünü anlamak için daha fazla çalışma gereklidir.

Anahtar Kelimeler

• prostat kanseri
• hücre proliferasyonu
• hippo sinyal yolağı
• YAP1

Kaynakça

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