Mild Hyperthermia (Approximately 39°C to 41°C
Pathways and Effects:
-Heat Shock Protein (HSP) Induction: Mild heat stress triggers the production of HSPs (e.g., HSP70, HSP90) that help cells cope with stress, which can sometimes provide a transient protective effect. However, these proteins can also act as immunomodulators.
-Modulation of the Immune System: Mild hyperthermia can enhance dendritic cell activation and improve antigen presentation, leading to the stimulation of anti-tumor immune responses.
-Vasodilation: Increased blood flow and improved oxygenation can sensitize tumors to radiation therapy and certain chemotherapeutics.
Moderate Hyperthermia (Approximately 41°C to 43°C)
Pathways and Effects:
-Enhanced Cytotoxicity: At temperatures in this range, tumor cells become more vulnerable to radiation and some chemotherapeutic agents. This is partly due to the inhibition of DNA repair pathways.
-Increased Permeability: Moderate heat can increase the permeability of cellular membranes, aiding in drug delivery and the uptake of chemotherapeutic agents.
-Induction of Apoptosis: Elevated temperatures can trigger apoptotic signaling pathways in cancer cells, sometimes in conjunction with other therapies.
High Hyperthermia / Thermal Ablation (Approximately 43°C to 50°C and above)
Pathways and Effects:
-Direct Cytotoxicity: High temperatures can lead to protein denaturation, membrane disruption, and direct cell death.
-Coagulative Necrosis: Sustained high temperatures cause irreversible cell injury leading to necrosis of tumor tissues.
-Vascular Damage: Hyperthermia in this range can damage tumor vasculature, reducing blood supply and indirectly causing tumor cell death.
-Enhanced Immune Response: Although high temperatures can cause immediate cell death, the release of tumor antigens and damage-associated molecular patterns (DAMPs) can stimulate an anti-tumor immune response
|