Local anesthetics elicit immune-dependent anticancer effects

Abstract

BackgroundRetrospective clinical trials reported a reduced local relapse rate, as well as improved overall survival after injection of local anesthetics during cancer surgery. Here, we investigated the anticancer effects of six local anesthetics used in clinical practice.ResultsIn vitro, local anesthetics induced signs of cancer cell stress including inhibition of oxidative phosphorylation, and induction of autophagy as well as endoplasmic reticulum (ER) stress characterized by the splicing of X-box binding protein 1 (XBP1s) mRNA, cleavage of activating transcription factor 6 (ATF6), phosphorylation of eIF2α and subsequent upregulation of activating transcription factor 4 (ATF4). Both eIF2α phosphorylation and autophagy required the ER stress-relevant eukaryotic translation initiation factor 2 alpha kinase 3 (EIF2AK3, best known as PERK). Local anesthetics also activated two hallmarks of immunogenic cell death, namely, the release of ATP and high-mobility group box 1 protein (HMGB1), yet failed to cause the translocation of calreticulin (CALR) from the ER to the plasma membrane. In vivo, locally injected anesthetics decreased tumor growth and improved survival in several models of tumors established in immunocompetent mice. Systemic immunotherapy with PD-1 blockade or intratumoral injection of recombinant CALR protein, increased the antitumor effects of local anesthetics. Local anesthetics failed to induce antitumor effects in immunodeficient mice or against cancers unable to activate ER stress or autophagy due to the knockout of EIF2AK3/PERK or ATG5, respectively. Uncoupling agents that inhibit oxidative phosphorylation and induce autophagy and ER stress mimicked the immune-dependent antitumor effects of local anesthetics.ConclusionAltogether, these results indicate that local anesthetics induce a therapeutically relevant pattern of immunogenic stress responses in cancer cells.

Trial watch: Toll-like receptor ligands in cancer therapy

“…injection, have not been much investigated. 67 Ongoing and future preclinical and clinical investigations are urgently awaited to define the recommendations for i.t. immunotherapy over systemic treatment for local monotherapies or combinatorial regimens.…”

Trial watch: local anesthetics in cancer therapy

“… 27 Interestingly, the chemical structure (ester or amide) does not seem to dictate cytotoxicity activity, whereas it is worth noting that chloroprocaine and prilocaine, which possess a short duration of action, induce fewer effects on cancer cells than agents with an extended time of efficacy. 28 Among the tested LAs, bupivacaine appears to be the most cytotoxic, while procaine is the least.…”

“…Of note, LAs can trigger the release of danger-associated molecular patterns (DAMPs) linked to immunogenic cell death (ICD), such as ATP and high mobility group box 1 (HMGB1), yet fail to promote the exposure of calreticulin at the plasma membrane. 28 , 72 ICD is accompanied by pre-mortem cellular stress responses, namely autophagy and endoplasmic reticulum (ER) stress that often precede and trigger the activation of various modalities of cell death. At clinically relevant concentrations, bupivacaine, chloroprocaine, levobupivacaine, lidocaine, ropivacaine and prilocaine induce the formation of autophagosomes, as indicated by the lipidation of autophagy-related protein light-chain 3B (LC3B), and activate the three arms of ER stress: i) the protein kinase RNA-like endoplasmic reticulum kinase (PERK) catalyzing the phosphorylation of eukaryotic initiation factor 2 alpha (EIF2A), which then favors the translation of activating transcription factor 4 (ATF4); ii) the inositol-requiring enzyme 1 (IRE1), which leads to the alternative splicing of X-box binding protein 1 (XBP1) mRNA; and iii) the cleavage of activating transcription factor 6 (ATF6) in the Golgi apparatus.…”

Impact of local anesthetics on epigenetics in cancer

“…Most studies failed to support a direct impact on clinical outcome. However, the continued accumulation of irrefutable preclinical data demonstrating antitumor effects of local anesthetics encourages clinicians to further pursue investigations as illustrated by several randomized controlled trials recorded at and summarized in ( 43 ). Among the published scientific readouts, it can be suspected that at least some of these effects are secondary to LA effects on the tumor epigenome.…”