PlGF blockade does not inhibit angiogenesis during primary tumor growth

Area of Science:

• Oncology
• Cancer Biology
• Immunotherapy

Background:

• Placenta growth factor (PlGF) and its receptor VEGFR-1 are implicated in tumor growth and metastasis.
• Anti-PlGF antibody therapy has shown potential in preclinical studies for inhibiting tumor progression.

Purpose of the Study:

• To investigate the role of PlGF in tumor angiogenesis and growth.
• To evaluate the efficacy of anti-PlGF antibodies, alone and in combination with anti-VEGF-A, in preclinical cancer models.

Main Methods:

• Neutralization of PlGF using four novel blocking antibodies.
• Genetic ablation of the tyrosine kinase domain of VEGFR-1.
• Assessment of tumor angiogenesis, metastasis, and primary tumor growth in 15 different models.
• Combination therapy with anti-PlGF and anti-VEGF-A antibodies.

Main Results:

• Anti-PlGF treatment inhibited wound healing and B16F10 cell extravasation but did not significantly affect tumor angiogenesis in 15 models.
• Genetic ablation of VEGFR-1 did not inhibit the growth of tested tumors.
• Combination therapy with anti-PlGF and anti-VEGF-A antibodies showed no superior antitumor efficacy compared to anti-VEGF-A monotherapy.

Conclusions:

• PlGF does not play a significant role in primary tumor growth across most tested models.
• The clinical utility of anti-PlGF antibodies for cancer treatment may be limited.
• Further research is needed to understand the complex roles of PlGF and VEGFR-1 in cancer progression.