Targeting RPL39 and MLF2 reduces tumor initiation and metastasis in breast cancer by inhibiting nitric oxide synthase signaling

• Published in: Proceedings of the National Academy of Sciences - PNAS 2014-06, Vol.111 (24), p.8838-8843
• Main Authors: Dave, Bhuvanesh, Granados-Principal, Sergio, Zhu, Rui, Benz, Stephen, Rabizadeh, Shahrooz, Soon-Shiong, Patrick, Yu, Ke-Da, Shao, Zhimin, Li, Xiaoxian, Gilcrease, Michael, Lai, Zhao, Chen, Yidong, Huang, Tim H.-M., Shen, Haifa, Liu, Xuewu, Ferrari, Mauro, Zhan, Ming, Wong, Stephen T. C., Kumaraswami, Muthiah, Mittal, Vivek, Chen, Xi, Gross, Steven S., Chang, Jenny C.
• Format: Article
• Language: English
• Subjects: Animals; Biological Sciences; biopsy; Breast cancer; breast neoplasms; Breast Neoplasms - metabolism; Breast Neoplasms - prevention & control; Cancer; Cell Line, Tumor; Cell lines; Cell Movement; Female; Gene Expression Regulation, Neoplastic; genes; Genetic mutation; Heterologous transplantation; High-Throughput Nucleotide Sequencing; Humans; Hypoxia; Lung Neoplasms - genetics; Lung Neoplasms - metabolism; Lungs; Metastasis; Mice; Mice, SCID; Mutation; myeloid leukemia; Nanoparticles; Neoplasm Metastasis; Neoplasm Transplantation; Neoplastic Stem Cells - cytology; Nitric oxide; Nitric Oxide - chemistry; nitric oxide synthase; Nitric Oxide Synthase - antagonists & inhibitors; Nitric Oxide Synthase - metabolism; Nuclear Proteins - metabolism; patients; Ribonucleic acid; Ribosomal Proteins - metabolism; RNA; RNA, Small Interfering - metabolism; Sequence Analysis, RNA; Signal Transduction; Small interfering RNA; Stem cells; Time Factors; Tumors
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1320769111

We previously described a gene signature for breast cancer stem cells (BCSCs) derived from patient biopsies. Selective shRNA knockdown identified ribosomal protein L39 (RPL39) and myeloid leukemia factor 2 (MLF2) as the top candidates that affect BCSC self-renewal. Knockdown of RPL39 and MLF2 by specific siRNA nanoparticles in patient-derived and human cancer xenografts reduced tumor volume and lung metastases with a concomitant decrease in BCSCs. RNA deep sequencing identified damaging mutations in both genes. These mutations were confirmed in patient lung metastases (n = 53) and were statistically associated with shorter median time to pulmonary metastasis. Both genes affect the nitric oxide synthase pathway and are altered by hypoxia. These findings support that extensive tumor heterogeneity exists within primary cancers; distinct subpopulations associated with stem-like properties have increased metastatic potential.