Acetyltanshinone IIA is more potent than lapatinib in inhibiting cell growth and degrading HER2 protein in drug-resistant HER2-positive breast cancer cells
CANCER LETTERS
Authors: Huang, Bin; Yip, Wai Kien; Wei, Na; Luo, Kathy Qian
Abstract
High expression of human epidermal factor receptor 2 (HER2) is directly related to tumor progression, malignancy and drug resistance in HER2-positive breast cancer (HER2-PBC). The major limitation of current anti-HER2 therapies is that they cannot reduce the levels of HER2 protein. Here, we investigated the effect of acetyltanshinone IIA (ATA) in lapatinib-resistant HER2-PBC cells. Our data showed that ATA exhibited more potent effects than lapatinib against drug-resistant HER2-PBC cells in terms of (1) inhibiting cell growth, (2) reducing phosphorylated and total HER2 levels, (3) inhibiting tumor xenograft growth in nude mice, and (4) reducing HER2 protein levels in tumor xenografts. A mechanistic study revealed that ATA promoted HER2 degradation via increasing c-Cbl and CHIP-mediated HER2 ubiquitination and subsequent HER2 degradation by the proteasome or lysosome. ATA also reduced the levels of other tyrosine kinase receptors (TKRs), such as HER3, IGF-1R and MET, in lapatinib-resistant cells. Our findings suggest that direct degradation of HER2 and other TKRs can be an effective strategy for combatting drug resistance. They also indicate the potential utilization of ATA in treating breast cancer that is resistant or nonresponsive to current HER2-targeted therapies.
Perinatal factors contributing to chronic kidney disease in a cohort of Japanese children with very low birth weight
PEDIATRIC NEPHROLOGY
Authors: Uemura, Osamu; Ishikura, Kenji; Kaneko, Tetsuji; Hirano, Daishi; Hamasaki, Yuko; Ogura, Masao; Mikami, Naoaki; Gotoh, Yoshimitsu; Sahashi, Takeshi; Fujita, Naoya; Yamamoto, Masaki; Hibino, Satoshi; Nakano, Masaru; Wakano, Yasuhiro; Honda, Masataka
Abstract
Background Developmental programming of chronic kidney disease (CKD) in young adults is linked to preterm birth and intrauterine growth restriction (IUGR). Which confers a higher risk of progression to chronic kidney damage in children with very low birth weight (VLBW; born weighing < 1500 g): prematurity or IUGR? Methods This is a national historical cohort study of children with VLBW cared for in perinatal medical centers in Japan. Predictive factors included three latent variables (prematurity, IUGR, stress during neonatal period) and eight observed variables (gestational age, birth weight Z-score, maternal age, duration of treatment with antibiotics and diuretics, maternal smoking, late-onset circulatory collapse, kidney dysfunction) during the perinatal period. The primary endpoint was estimated glomerular filtration rate (eGFR) at age >= 3 years. A structural equation model was used to examine the pathologic constitution. Results The 446 children with VLBW included 253 boys and 193 girls, of mean age 5.8 +/- 2.6 years and mean eGFR 111.7 ml/min/1.73 m(2)at last encounter. Pathway analyses showed intrauterine malnutrition (beta= 0.85) contributed more to chronic kidney damage than stress during the neonatal period (beta= - 0.19) and prematurity (beta= 0.12), and kidney dysfunction and late-onset circulatory collapse were important observed variables in stress during the neonatal period. Conclusions IUGR was more harmful to future kidneys of VLBW neonates. Neonatal kidney dysfunction and late-onset circulatory collapse were important risk factors for subsequent CKD development. This emphasizes the need for obstetricians to monitor for fetal growth restriction and neonatologists to minimize neonatal stress to prevent CKD in later life.