Impaired PTPN13 Phosphatase Activity Exacerbates Squamous Cell Carcinoma Growth

Strategic Insights -

In a groundbreaking study published in Oncogene, scientists have unveiled the crucial role of PTPN13 phosphatase activity in regulating MAP kinase signaling in squamous cell carcinoma. Cervical and head and neck cancers, caused by human papillomaviruses (HPVs), have been found to exploit the impaired PTPN13 phosphatase activity to fuel invasive growth in vivo. The researchers demonstrated that PTPN13 loss synergizes with oncogenes such as H-Ras(V12) or ErbB2 to promote Ras/RAF/MEK/Erk signaling, a critical pathway for cancer progression.

Key Takeaways:

  • The study found that over 90% of cervical and 25% of head and neck squamous cell carcinomas (HNSCCs) are caused by human papillomaviruses (HPVs).
  • The C terminus of the high-risk HPV 16 E6 oncoprotein physically associates with and degrades the non-receptor protein tyrosine phosphatase (PTPN13).
  • PTPN13 loss was found in 20% of HPV-negative HNSCCs, driven by mutations that did not inhibit Ras/RAF/MEK/Erk signaling.
  • Co-transfection studies revealed that wild-type PTPN13 inhibited Ras/RAF/MEK/Erk signaling in cells overexpressing ErbB2, EGFR, or H-Ras(V12).
  • The researchers demonstrated that inhibition of Ras/RAF/MEK/Erk signaling using MEK inhibitor U0126 blocked anchorage-independent growth in cells lacking PTPN13.

Statistics:

  • 90% of cervical cancers are caused by human papillomaviruses (HPVs) [1].
  • 25% of head and neck squamous cell carcinomas (HNSCCs) are caused by human papillomaviruses (HPVs) [1].
  • 20% of HPV-negative HNSCCs have PTPN13 phosphatase mutations [1].

Sources:

  • Hoover, A. C., et al. (2009). Impaired PTPN13 phosphatase activity in spontaneous or HPV-induced squamous cell carcinomas potentiates oncogene signaling through the MAP kinase pathway. Oncogene, 28(45), 3960-3970.
  • [No additional sources were provided]