Lidocaine Enhanced Antitumor Efficacy and Relieved Chemotherapy-Induced Hyperalgesia in Mice with Metastatic Gastric Cancer

Abstract

With the widespread use of lidocaine for pain control in cancer therapy, its antitumor activity has attracted considerable attention in recent years. This paper provides a simple strategy of combining lidocaine with chemotherapy drugs for cancer therapy, aiming to relieve chemotherapy-induced pain and achieve stronger antitumor efficacy. However, there is still a lack of substantial pre-clinical evidence for the efficacy and related mechanisms of such combinations, obstructing their potential clinical application. In this study, we propose intraperitoneal chemotherapy (IPC) against gastric cancer (GC) as an ideal scenario to evaluate the efficacy of a lidocaine/paclitaxel combination. Firstly, we used human GC cells MKN-45-luc to investigate the antitumor activity and related mechanisms of the lidocaine/paclitaxel combination in vitro. Then, we used C57BL/6 mice with intraperitoneal drug suffusion to evaluate the efficacy of lidocaine to suppress paclitaxel-induced hyperalgesia and related mechanisms. Lastly, in BALB/c tumor-bearing nude mice we evaluated the synergistic antitumor activity and pain-relieving effect of the lidocaine/paclitaxel combination. Our results showed enhanced antitumor activity for the lidocaine/paclitaxel combination, which induced apoptosis, inhibited migration, and the invasion of GC cells in a synergistic manner. In animal models, the lidocaine/paclitaxel combination effectively inhibited growth and peritoneal metastasis of the tumor, resulting in prolonged survival time. Meanwhile, lidocaine showed considerable anti-inflammatory activity alongside its anesthetic effect, which, in combination, effectively relieved hyperalgesia induced by paclitaxel. These results suggested that intraperitoneal suffusion with lidocaine/paclitaxel could be a pain-free IPC formulation with enhanced antitumor activity, which could provide a promising treatment for GC with peritoneal metastasis.

Keywords: chemotherapy-induced hyperalgesia; gastric cancer; intraperitoneal suffusion; local anesthetics; peritoneal metastasis; synergistic antitumor.

Figure 1

Schematic illustration for investigating the synergistic antitumor and pain-relieving efficacy of the Lido/PTX combination.

Figure 2

Synergistic effect of Lido and PTX on cell viability and apoptosis of MKN-45-luc cells. (A) Viability of cells treated with Lido and PTX at different concentrations (n = 3). (B) CI values of Lido and PTX at different concentrations. (C) Representative flow cytometry images. (D) Apoptosis rates (n = 4). (E) Western blot analysis of apoptotic marker proteins in the control, Lido, PTX, and Lido/PTX groups. GAPDH was used as an internal control. Data are presented as the mean ± standard deviation (SD) and statistical significance was assessed by one-way ANOVA. *** p < 0.001.

Figure 3

Synergistic effect of Lido and PTX on migration and invasion of MKN-45-luc cells. (A) Representative images of cell migration by scratch assay. (B) Relative migration rates (n = 4). (C) Representative images of cell invasion. (D) Relative invasion rates (n = 4). (E) Western blot analysis of E-cadherin in the control, Lido, PTX, and Lido/PTX groups. Data are presented as the mean ± SD and statistical significance was assessed by one-way ANOVA. * p < 0.05, *** p < 0.001.

Figure 4

Analgesic effect of Lido on PTX-induced hyperalgesia. (A) Schematic diagram of the model establishment and treatment schedule (n = 5). (B) The PWT in response to mechanical stimulus. (C) The tail-flick latency in response to ice-water stimulus. (D) The paw withdrawal latency to acetone stimulus. (E) Representative immunofluorescence images of c-Fos+ and TRPV1+ cells in DRG (n = 3). (F) Statistic analysis of MFI of c-Fos signal. (G) Statistic analysis of the portion of c-Fos+ cells in all TRPV1+ cells. Data are presented as the mean ± SD and statistical significance was assessed by one-way ANOVA. * p < 0.05, ** p < 0.01.

Figure 5

Anti-inflammatory effect of Lido in the Lido/PTX combination. (A) TNF-α, (B) IL-1β, and (C) IL-6 secreted from macrophages treated for 24 h by different groups (n = 3). (D) Representative images of H&E-stained sections of tissue from different groups (n = 3). Accumulation of inflammatory cells was pointed out by the black arrows. (E) Representative immunofluorescence images of TNF-α expressed in DRG (n = 3). (F) Statistic analysis of MFI of TNF-α signal (n = 3). Data are presented as the mean ± SD and statistical significance was assessed by one-way ANOVA. * p < 0.05, *** p < 0.001.

Figure 6

Lido/PTX combination inhibited tumor growth in a peritoneal metastatic GC model. (A) Schematic diagram of the model establishment and treatment schedule (n = 5). (B) Luminescence images obtained through In Vivo Imaging System (IVIS) imaging weekly. (C) Quantification of luminescence measurements. (D) Body weight of mice. (E) Representative photographs of peri-gastric mesenteric tumor nodules on day 27 after different treatments. (F) Weight of tumor nodules. (G) Total number of tumor nodules. (H) Number of tumor nodules in different tumor volume ranges. (I) Representative images of H&E-stained sections of tissue from different groups. Data are presented as the mean ± SD and statistical significance was assessed by one-way ANOVA. * p < 0.05, ** p < 0.01, *** p < 0.001 between Lido/PTX and PTX.

Figure 7

Lido/PTX combination group enhanced survival time and inhibited PTX-induced hyperalgesia in a peritoneal metastatic GC model. (A) Schematic diagram of the model establishment and treatment schedule (n = 5). (B) Luminescence images obtained through IVIS imaging weekly. (C) Quantification of luminescence measurements. (D) Survival rate, (E) survival time, and (F) body weight of mice. (G) The paw withdrawal threshold by mechanical stimuli. (H) The tail-flick latency to ice-water. (I) The paw withdrawal latency to acetone. Data are presented as the mean ± SD and statistical significance was assessed by one-way ANOVA. * p < 0.05, ** p < 0.01, *** p < 0.001 between Lido/PTX and PTX.