R‐ketorolac ameliorates cancer‐associated cachexia and prolongs survival of tumour‐bearing mice

Abstract

BackgroundCancer‐associated cachexia (CAC) is a debilitating syndrome associated with poor quality of life and reduced life expectancy of cancer patients. CAC is characterized by unintended body weight reduction due to muscle and adipose tissue loss. A major hallmark of CAC is systemic inflammation. Several non‐steroidal anti‐inflammatory drugs (NSAIDs) have been suggested for CAC treatment, yet no single medication has proven reliable. R‐ketorolac (RK) is the R‐enantiomer of a commonly used NSAID. The effect of RK on CAC has not yet been evaluated.MethodsTen‐ to 11‐week‐old mice were inoculated with C26 or CHX207 cancer cells or vehicle control (phosphate‐buffered saline [PBS]). After cachexia onset, 2 mg/kg RK or PBS was administered daily by oral gavage. Body weight, food intake and tumour size were continuously measured. At study endpoints, blood was drawn, mice were sacrificed and tissues were excised. Immune cell abundance was analysed using a Cytek® Aurora spectral flow cytometer. Cyclooxygenase (COX) activity was determined in lung homogenates using a fluorometric kit. Muscle tissues were analysed for mRNA and protein expression by quantitative real‐time PCR and western blotting analysis, respectively. Muscle fibre size was determined on histological slides after haematoxylin/eosin staining.ResultsTen‐day survival rate of C26‐bearing animals was 10% while RK treatment resulted in a 100% survival rate (P = 0.0009). Chemotherapy resulted in a 10% survival rate 14 days after treatment initiation, but all mice survived upon co‐medication with RK and cyclophosphamide (P = 0.0001). Increased survival was associated with a protection from body weight loss in C26 (−0.61 ± 1.82 vs. −4.48 ± 2.0 g, P = 0.0004) and CHX207 (−0.49 ± 0.33 vs. −2.49 ± 0.93 g, P = 0.0003) tumour‐bearing mice treated with RK, compared with untreated mice. RK ameliorated musculus quadriceps (−1.7 ± 7.1% vs. −27.8 ± 8.3%, P = 0.0007) and gonadal white adipose tissue (−18.8 ± 49% vs. −69 ± 15.6%, P = 0.094) loss in tumour‐bearing mice, compared with untreated mice. Mechanistically, RK reduced circulating interleukin‐6 (IL‐6) concentrations from 334 ± 151 to 164 ± 123 pg/mL (P = 0.047) in C26 and from 93 ± 39 to 35 ± 6 pg/mL (P = 0.0053) in CHX207 tumour‐bearing mice. Moreover, RK protected mice from cancer‐induced T‐lymphopenia (+1.8 ± 42% vs. −49.2 ± 12.1% in treated vs. untreated mice, respectively). RK was ineffective in ameliorating CAC in thymus‐deficient nude mice, indicating that the beneficial effect of RK depends on T‐cells.ConclusionsRK improved T‐lymphopenia and decreased systemic IL‐6 concentrations, resulting in alleviation of cachexia and increased survival of cachexigenic tumour‐bearing mice, even under chemotherapy and independent of COX inhibition. Considering its potential, we propose that the use of RK should be investigated in patients suffering from CAC.

Immune System Disorder and Cancer-Associated Cachexia

“…Symptoms of CAC such as anorexia, lower food intake, and a decline in the quality of life were observed in patients with high NLR. These findings suggest the potential utility of including NLR in diagnostic assessments for CAC prognosis and treatment approaches [23,24]. This study establishes a correlation between immune disorder and survival in CAC.…”

“…Significantly, in the C26 mice model, a combined treatment of R-ketorolac and chemotherapy resulted in a 100% survival rate. These pre-clinical observations highlight the therapeutic potential of immunomodulators in treating CAC [23].…”

“…This is particularly noteworthy since a major drawback of long-term NSAID use is the side effect of COX-1 inhibition [28]. Thus, R-ketorolac can alleviate CAC symptoms by modulating the immune system towards a near-normal state, preventing death in C26 mice [23]. Importantly, treating CAC through immunomodulation may improve the inferior response of patients with elevated inflammatory markers to checkpoint inhibitor immunotherapy [29][30][31].…”

Immune System Disorder and Cancer-Associated Cachexia

“…Symptoms of CAC such as anorexia, lower food intake, and a decline in quality of life were observed in patients with high NLR. These findings suggest the potential utility of including NLR in diagnostic assessments for CAC prognosis and treatment approaches [22,23]. This study establishes a correlation between immune disorder and survival in CAC.…”

“…R-ketorolac's reversal of CAC and its immune modulatory effects appear to be independent of COX inhibition. These pre-clinical observations highlight the therapeutic potential of immunomodulators in treating CAC [22].…”