No abstract

BackgroundCancer‐associated wasting, termed cancer cachexia, has a profound effect on the morbidity and mortality of cancer patients but remains difficult to recognize and diagnose. While increases in circulating levels of a number of inflammatory cytokines have been associated with cancer cachexia, these associations were generally made in patients with advanced disease and thus may be associated with disease progression rather than directly with the cachexia syndrome. Thus, we sought to assess potential biomarkers of cancer‐induced cachexia in patients with earlier stages of disease.MethodsA custom multiplex array was used to measure circulating levels of 25 soluble factors from 70 pancreatic cancer patients undergoing attempted tumour resections. A high‐sensitivity multiplex was used for increased sensitivity for nine cytokines.ResultsResectable pancreatic cancer patients with cachexia had low levels of canonical pro‐inflammatory cytokines including interleukin‐6 (IL‐6), interleukin‐1β (IL‐1β), interferon‐γ (IFN‐γ), and tumour necrosis factor (TNF). Even in our more sensitive analysis, these cytokines were not associated with cancer cachexia. Of the 25 circulating factors tested, only monocyte chemoattractant protein‐1 (MCP‐1) was increased in treatment‐naïve cachectic patients compared with weight stable patients and identified as a potential biomarker for cancer cachexia. Although circulating levels of leptin and granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) were found to be decreased in the same cohort of treatment‐naïve cachectic patients, these factors were closely associated with body mass index, limiting their utility as cancer cachexia biomarkers.ConclusionsUnlike in advanced disease, it is possible that cachexia in patients with resectable pancreatic cancer is not associated with high levels of classical markers of systemic inflammation. However, cachectic, treatment‐naïve patients have higher levels of MCP‐1, suggesting that MCP‐1 may be useful as a biomarker of cancer cachexia.

Background: Cachexia is a wasting syndrome characterized by involuntary loss of >5% body weight due to depletion of adipose and skeletal muscle mass. In cancer, the pro-inflammatory cytokine interleukin-6 (IL-6) is considered a mediator of cachexia and a potential biomarker, but the relationship between IL-6, weight loss, and cancer stage is unknown. In this study we sought to evaluate IL-6 as a biomarker of cancer cachexia while accounting for disease progression. Methods: We retrospectively studied 136 subjects with biopsy-proven pancreatic ductal adenocarcinoma (PDAC), considering the high prevalence of cachexia is this population. Clinical data were abstracted from subjects in all cancer stages, and plasma IL-6 levels were measured using a multiplex array and a more sensitive ELISA. Data were evaluated with univariate comparisons, including Kaplan-Meier survival curves, and multivariate Cox survival models. Results: On multiplex, a total of 43 (31.4%) subjects had detectable levels of plasma IL-6, while by ELISA all subjects had detectable IL-6 levels. We found that increased plasma IL-6 levels, defined as detectable for multiplex and greater than median for ELISA, were not associated with weight loss at diagnosis, but rather with the presence of metastasis (p<0.001 for multiplex and p=0.007 for ELISA). Further, while >5% weight loss was not associated with worse survival, increased plasma IL-6 by either methodology was. Conclusion: Circulating IL-6 levels do not correlate with weight loss (i.e., cachexia), but rather with advanced cancer stage. This suggests that IL-6 may mediate wasting, but should not be considered a diagnostic biomarker for PDAC-induced cachexia.

Involuntary weight loss, a part of the cachexia syndrome, is a debilitating co-morbidity of cancer and currently has no treatment options. Results from a recent clinical trial at our institution showed that biliary tract cancer patients treated with a MEK inhibitor exhibited poor tumor responses, but surprisingly gained weight and increased their skeletal muscle mass. This implied that MEK inhibition might be anti-cachectic. To test this potential effect of MEK inhibition, we utilized the established Colon-26 model of cancer cachexia and the MEK1/2 inhibitor MEK162. Results showed that MEK inhibition effectively prevented muscle wasting. Importantly, MEK162 retained its ability to spare muscle loss even in mice bearing a Colon-26 clone resistant to the MEK inhibitor, demonstrating that the effects of blocking MEK is at least in part independent of the tumor. Because single agent MEK inhibitors have been limited as a front-line targeted therapy due to compensatory activation of other oncogenic signaling pathways, we combined MEK162 with the PI3K/Akt inhibitor buparlisib. Results showed that this combinatorial treatment significantly reduced tumor growth due to a direct activity on Colon-26 tumor cells in vitro and in vivo, while also preserving skeletal muscle mass. Together, our results suggest that as a monotherapy MEK inhibition preserves muscle mass, but when combined with a PI3K/Akt inhibitor exhibits potent anti-tumor activity. Thus, combinatorial therapy might serve as a new approach for the treatment of cancer cachexia.