Tumor Vasculature and Acidic Tumor Microenvironment (TME)

The tumor vasculature and acidic tumor microenvironment (TME) are interconnected physiological hallmarks of solid tumors that facilitate progression and therapy resistance. Tumor vasculature is typically disorganized and hyperpermeable due to excessive pro-angiogenic signaling, primarily via the Vascular Endothelial Growth Factor (VEGF) pathway (Carmeliet & Jain, 2011, Nature). This structural abnormality leads to poor perfusion and hypoxia, which triggers the "Warburg effect"—a metabolic shift toward glycolysis even in the presence of oxygen. The resulting accumulation of lactic acid and protons creates an acidic extracellular environment (pH 6.5–6.9), which promotes immune evasion, extracellular matrix degradation, and metastasis (Vaupel & Mayer, 2017, Cancer Metastasis Rev). Therapeutic strategies targeting these features involve "vascular normalization" using anti-angiogenic agents like Bevacizumab to improve drug delivery and oxygenation. Simultaneously, researchers are targeting the acidic TME by inhibiting pH-regulating proteins such as Carbonic Anhydrase IX (CAIX) and Monocarboxylate Transporters (MCTs), or by using pH-sensitive drug delivery systems that release cytotoxic payloads specifically in acidic conditions (Neri & Supuran, 2011, Nat Rev Drug Discov). These approaches aim to reverse the immunosuppressive and chemoresistant nature of the tumor niche, thereby enhancing the efficacy of standard-of-care treatments.

Other names

Tumor microenvironmentAcidic TMETumor stromaAngiogenic tumor vasculatureExtracellular acidosis

Inhibition of pro-angiogenic signaling (e.g., VEGF/VEGFR) and pH-regulating enzymes (e.g., CAIX, MCT1) to normalize the tumor environment and enhance therapeutic efficacy.