TY - JOUR T1 - Total Knockdown of LMW-PTP in MDA-MB-231 Cells Reduces Osteoclastogenesis JF - Anticancer Research JO - Anticancer Res SP - 6671 LP - 6677 VL - 37 IS - 12 AU - GUILHERME SAPINHO AU - IRINA ALHO AU - MANUEL BICHO AU - CONSTANÇA COELHO Y1 - 2017/12/01 UR - http://ar.iiarjournals.org/content/37/12/6671.abstract N2 - Background: Low molecular weight protein tyrosine phosphatase (LMW-PTP) has been related to tumorigenesis, having both oncogenic and anti-oncogenic roles. The differential roles of its main active isoforms (fast and slow) may account for these discrepancies. The fast isoform has been described to be involved in the bone-metastatic process, although knockdown of the slow isoform was recently reported to reduce osteoclastogenesis. We aimed to study the influence of LMW-PTP isoforms on osteoclast differentiation. Materials and Methods: Osteoclast precursors (RAW 264.7) were cultured with conditioned medium from MDA-MB-231 breast cancer cells with total knockdown of LMW-PTP and with knockdown of the slow isoform of LMW-PTP. Tartarate-resistant acid phosphatase (TRAP) staining and quantification were performed to assess osteoclast differentiation. Results: Total knockdown of LMW-PTP, but not of slow LMW-PTP significantly reduced osteoclast differentiation of RAW 264.7 cells. Conclusion: We suggest that total LMW-PTP increases osteoclastic differentiation, albeit not at the expense of the slow isoform. ER -