Degradation of HER2 by Cbl-based chimeric ubiquitin ligases.
Targeting disease-causing proteins for ubiquitination and degradation by chimeric molecules represents a promising alternative therapeutic strategy in cancer. Here, several Cbl-based chimeric ubiquitin ligases were recombined to achieve effective down-regulation of HER2. These chimeric molecules consisted of the Cbl NH(2)-terminal tyrosine kinase binding domain, linker, and RING domain, with the Src homology 2 domain replaced with that from growth factor receptor binding protein 2 (Grb2), Grb7, p85, or Src. The chimeric proteins not only interacted with HER2 but also enhanced the down-regulation of endogenous overexpressed HER2. After the chimeric proteins were introduced into HER2-overexpressing breast cancer SK-BR-3 cells or ovarian cancer SK-OV-3 cells, they effectively promoted HER2 ubiquitination and degradation in a RING finger domain-dependent manner. Consequently, expression of these chimeric molecules led to an inhibition of colony formation, increased the proportion of cells in the G(1) cycle, and suppressed tumorigenicity. Collectively, our findings suggest that the Cbl-based chimeric ubiquitin ligases designed in the present study may represent a novel approach for the targeted therapy of HER2-overexpressing cancers.
Li
Xia
X
State Key Laboratory of Cancer Biology, Department of Biochemistry and Molecular Biology, The Fourth Military Medical University, Xi'an, China.
Shen
Liangliang
L
Zhang
Jing
J
Su
Jin
J
Shen
Lan
L
Liu
Xinping
X
Han
Hua
H
Han
Wei
W
Yao
Libo
L
D000818:Animals; D001943:Breast Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000628:therapy*; D002453:Cell Cycle / Q000502:physiology; D048708:Cell Growth Processes / Q000502:physiology; D045744:Cell Line, Tumor; D015536:Down-Regulation; D005260:Female; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D010051:Ovarian Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000473:pathology / Q000628:therapy*; D017434:Protein Structure, Tertiary; D050721:Proto-Oncogene Proteins c-cbl / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D023041:Xenograft Model Antitumor Assays; D018909:src Homology Domains / Q000235:genetics
D050721:Proto-Oncogene Proteins c-cbl; D018719:Erb-b2 Receptor Tyrosine Kinases; D011993:Recombinant Fusion Proteins; C067419:CBL protein, human