Mechanisms of buffer therapy resistance

Area of Science:

• Oncology
• Cancer Biology
• Tumor Microenvironment

Background:

• Solid tumor acidity is a known driver of local invasion and metastasis.
• Oral pH buffers have shown promise in reducing metastasis in preclinical models.
• However, buffer efficacy is not universal, with some tumor models exhibiting resistance.

Purpose of the Study:

• To investigate the distinct mechanisms underlying pH-dependent and pH-independent metastasis.
• To understand why certain tumors are resistant to pH buffer therapy.
• To identify potential therapeutic strategies based on these mechanisms.

Main Methods:

• Utilized murine models with varying sensitivity to lysine buffer therapy (B16-F10, LL/2, HCT116 resistant; MDA-MB-231, PC3M sensitive).
• Analyzed cellular phenotypes, including glycolytic activity and matrix-degrading protease secretion.
• Correlated metastatic mechanisms with response to pH buffer treatment.

Main Results:

• Sensitive cell lines employed a pH-dependent metastatic mechanism linked to high glycolysis and tumor microenvironment acidification.
• Resistant cell lines exhibited a pH-independent metastatic mechanism involving constitutive protease secretion without increased glycolysis.
• Identified two distinct pathways for experimental metastasis: one sensitive to pH buffers, the other resistant.

Conclusions:

• Two distinct mechanisms of experimental metastasis exist: pH-dependent and pH-independent.
• pH-dependent metastasis is sensitive to buffer therapy, while pH-independent metastasis is not.
• Understanding these mechanisms offers potential for developing targeted therapeutic interventions for cancer metastasis.