Current Therapeutic Targets in Cancer Cachexia: A Pathophysiologic Approach

Testosterone replacement therapy in patients with cachexia: a contemporary review of the literature

INTRODUCTION

Patients with long-term chronic illnesses frequently present with hypogonadism, which is primarily managed through exogenous testosterone. These same patients also experience a high degree of cachexia, a loss of skeletal muscle and adipose tissue.

OBJECTIVE

To perform a contemporary review of the literature to assess the effectiveness of testosterone replacement therapy (TRT) for managing chronic disease-associated cachexia.

METHODS

We performed a PubMed literature search using MeSH terms to identify studies from 2000 to 2022 on TRT and the following cachexia-related chronic medical diseases: cancer, COPD, HIV/AIDS, and liver cirrhosis.

RESULTS

From the literature, 11 primary studies and 1 meta-analysis were selected. Among these studies, 3 evaluated TRT on cancer-associated cachexia, 3 on chronic obstructive pulmonary disease, 4 on HIV and AIDS, and 2 on liver cirrhosis. TRT showed mixed results favoring clinical improvement on each disease.

CONCLUSIONS

Cachexia is commonly observed in chronic disease states. Its occurrence with hypogonadism, alongside the shared symptoms of these 2 conditions, points toward the management of cachexia through the administration of exogenous testosterone. Robust data in the literature support the use of testosterone in increasing lean body mass, improving energy levels, and enhancing the quality of life for patients with chronic disease. However, the data are variable, and further studies are warranted on the long-term efficacy of TRT in patients with cachexia.

Relationships of emerging biomarkers of cancer cachexia with quality of life, appetite, and cachexia

PURPOSE

Quality of life (QoL), appetite, cachexia, and biomarkers [albumin, hemoglobin (Hb), neutrophils, lymphocytes, platelets, C-reactive protein (CRP), tumor necrosis factor alpha (TNFα), interleukin 6 (IL-6), interleukin 8 (IL-8), C-X-C motif chemokine ligand 5 (CXCL5) and citrullinated histoneH3 (H3Cit)] were compared for 40 cases with advanced cancer and 40 healthy controls. Baseline differences and significant relationships were explored for biomarkers with QoL, appetite, and cachexia.

METHODS

In a prospective case-control, age and sex matched study, the European Organisation for the Research and Treatment of Cancer Quality of Life-C30 questionnaire (EORTC-QLQ-C30) for QoL, the Functional Assessment of Anorexia and Cachexia Therapy assessment (FAACT A/CS-12) for appetite, and a five-factor cachexia assessment tool for cachexia assessment were performed. Routine hematological measurements and blood chemistry analyses together with ELISA procedures and a Multiplex® bead array platform, were used for biomarker analysis. Descriptive statistics and regression analyses were undertaken. P < 0.05 defined statistical significance.

RESULTS

Global health status (QL-G), functional scales (QL-FS), and symptom scales (QL-SS) differed for cases and controls (p < 0.01). In cases, differences were observed for QL-G (p < 0.01), QL-FS (p < 0.01), and QL-SS (p = 0.01) compared to standardized references values. FAACT A/CS-12 scores differed significantly between cases and controls (p < 0.01) and 30% of cases scored "poor" appetites. Cachexia was present in 60% of cases. Albumin, lymphocytes, platelets, Hb, platelet to lymphocyte ratio (PLR), systemic immune-inflammation index (SII), CRP, TNFα, all at p < 0.01, neutrophil to lymphocyte ratio (NLR) (p = 0.02), IL-6 (p < 0.04), and IL-8 (p = 0.02) differed significantly between cases and controls. No difference was found for CXCL5 or H3Cit. Albumin NLR, Hb, PLR, SII, TNFα, IL-8, and CRP showed significant relationships with all aspects of QoL. QL-FS was significantly related to CXCL5 (p = 0.04), significant relationships with FAACT A/CS-12 included: NLR (p = 0.002), Hb (p < 0.001), and PLR (p < 0.01). NLR, PLR, SII, TNFα, IL-6, IL-8, and CRP correlated positively to cachexia and albumin while Hb and lymphocyte count correlated negatively to cachexia.

CONCLUSION

CXCL5 and H3Cit were not reliable biomarkers for cancer cachexia, nor significantly related to QoL, appetite or cachexia. Albumin, NLR, Hb, PLR, SII, TNFα, IL-8, and CRP were reliable indicators of QoL, appetite, and cachexia. Future research should include other novel biomarkers namely growth differentiation factor-15 (GDF-15), fibroblast growth factor 21 (FGF-21), fractakline, interferon gamma (IFN-y), IL-16, macrophage colony stimulating factor (M-CSF), and macrophage procoagulant-inducing factor (MPIF).

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

BACKGROUND

Cancer-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.

METHODS

Ten- 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.

RESULTS

Ten-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.

CONCLUSIONS

RK 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.

[Cancer-associated cachexia: an unresolved disease]

Cachexia is a systemic wasting condition associated to advanced phases of many cancers, which contributes to significant morbidity and mortality. It is mainly characterized by involuntary weight loss due to muscle wasting often associated with loss of adipose tissue, possibly leading to inanition and death, without treatment to date. Symptomatology covers a complex array of disorders (fatigue, inflammation, pain, anorexia, depression) related to multisystemic impairments progressively affecting numerous organs and tissues (muscle, adipose tissue, brain, immune system, gastrointestinal tract). The mechanisms of induction and progression of the disease, still poorly understood, involve inflammatory, metabolic, and neuroendocrine drivers, triggered by a variety of mediators originating from tumor, tumor-host interactions, and inter-organ crosstalk.

Bridging gaps in cancer cachexia Care: Current insights and future perspectives

Cachexia is characterized by severe weight loss and skeletal muscle depletion, and is a threat to cancer patients by worsening their prognosis. International guidelines set indications for the screening and diagnosis of cancer cachexia and suggest interventions (nutritional support, physical exercise, and pharmacological treatments). Nevertheless, real-life experience not always aligns with such indications. We aimed to review the current state of the field and the main advancements, with a focus on real-life clinical practice from the perspectives of oncologists, nutrition professionals, and radiologists. Pragmatic solutions are proposed to improve the current management of the disease, emphasizing the importance of increasing awareness of clinical nutrition's benefits, fostering multidisciplinary collaboration, promoting early identification of at-risk patients, and leveraging available resources. Given the distinct needs of patients who are receiving oncologic anti-cancer treatments and those in the follow-up phase, the use of tailored approaches is encouraged. The pivotal role of healthcare professionals in managing patients in active treatment is highlighted, while patient and caregiver empowerment should be strengthened in the follow-up phase. Telemedicine and web-based applications represent valuable tools for continuous monitoring of patients, facilitating timely and personalized intervention through effective communication between patients and healthcare providers. These actions can potentially improve the outcomes, well-being, and survival of cancer patients with cachexia.

Age-related and cancer-related sarcopenia: is there a difference?

PURPOSE

The aim of this review is the attempt to differentiating the pathophysiologic and clinical features of the aging-related sarcopenia from cancer-related sarcopenia. In fact, there is some controversy among the experts mainly regarding two points: is always sarcopenia, even that aging-related one, the expression of a generalized disease or may exist independently and without major alteration of the muscle function? Are always aging-related and cancer-related sarcopenia completely separated entities?

RECENT FINDINGS

Literature shows that sarcopenia, defined as simple skeletal muscle mass loss, may range from a mainly focal problem which is common in many healthy elderly people, to a component of a complex multiorgan syndrome as cancer cachexia. Disuse, malnutrition and (neuro)degenerative processes can account for most of the aging-related sarcopenias while systemic inflammation and secretion of cancer-and immune-related molecules play an additional major role in cachexia.

SUMMARY

A multimodal approach including physical exercise and optimized nutritional support are the key measures to offset sarcopenia with some contribution by the anti-inflammatory drugs in cancer patients. Results are more promising in elderly patients and are still pending for cancer patients where a more specific approach will only rely on the identification and contrast of the key mediators of the cachectic process.

Advancing cancer cachexia diagnosis with -omics technology and exercise as molecular medicine

Muscle atrophy exacerbates disease outcomes and increases mortality, whereas the preservation of skeletal muscle mass and function play pivotal roles in ensuring long-term health and overall quality-of-life. Muscle atrophy represents a significant clinical challenge, involving the continued loss of muscle mass and strength, which frequently accompany the development of numerous types of cancer. Cancer cachexia is a highly prevalent multifactorial syndrome, and although cachexia is one of the main causes of cancer-related deaths, there are still no approved management strategies for the disease. The etiology of this condition is based on the upregulation of systemic inflammation factors and catabolic stimuli, resulting in the inhibition of protein synthesis and enhancement of protein degradation. Numerous necessary cellular processes are disrupted by cachectic pathology, which mediate intracellular signalling pathways resulting in the net loss of muscle and organelles. However, the exact underpinning molecular mechanisms of how these changes are orchestrated are incompletely understood. Much work is still required, but structured exercise has the capacity to counteract numerous detrimental effects linked to cancer cachexia. Primarily through the stimulation of muscle protein synthesis, enhancement of mitochondrial function, and the release of myokines. As a result, muscle mass and strength increase, leading to improved mobility, and quality-of-life. This review summarises existing knowledge of the complex molecular networks that regulate cancer cachexia and exercise, highlighting the molecular interplay between the two for potential therapeutic intervention. Finally, the utility of mass spectrometry-based proteomics is considered as a way of establishing early diagnostic biomarkers of cachectic patients.

Progressive, multi-organ, and multi-layered nature of cancer cachexia

Cancer cachexia is a complex, multifaceted condition that negatively impacts the health, treatment efficacy, and economic status of cancer patients. The management of cancer cachexia is an essential clinical need. Cancer cachexia is currently defined mainly according to the severity of weight loss and sarcopenia (i.e., macrosymptoms). However, such macrosymptoms may be insufficient to give clinicians clues on how to manage this condition as these symptoms appear at the late stage of cancer. We need to understand earlier events during the progression of cancer cachexia so as not to miss a clinical opportunity to control this complex syndrome. Recent research indicates that cancer-induced changes in the host are much wider than previously recognized, including disruption of liver function and the immune system. Furthermore, such changes are observed before the occurrence of visible distant metastases (i.e., in early, localized cancers). In light of these findings, we propose to expand the definition of cancer cachexia to include all cancer-induced changes to host physiology, including changes caused by early, localized cancers. This new definition of cancer cachexia can provide a new perspective on this topic, which can stimulate the research and development of novel cancer cachexia therapies.

Leucine Supplementation Exacerbates Morbidity in Male but Not Female Mice with Colorectal Cancer-Induced Cachexia

Cancer cachexia (CC) is a multifactorial wasting syndrome characterized by a significant loss in lean and/or fat mass and represents a leading cause of mortality in cancer patients. Nutraceutical treatments have been proposed as a potential treatment strategy to mitigate cachexia-induced muscle wasting. However, contradictory findings warrant further investigation. The purpose of this study was to determine the effects of leucine supplementation on skeletal muscle in male and female ApcMin/+ mice (APC). APC mice and their wild-type (WT) littermates were given normal drinking water or 1.5% leucine-supplemented water (n = 4-10/group/sex). We measured the gene expression of regulators of inflammation, protein balance, and myogenesis. Leucine treatment lowered survival rates, body mass, and muscle mass in males, while in females, it had no effect on body or muscle mass. Leucine treatment altered inflammatory gene expression by lowering Il1b 87% in the APC group and decreasing Tnfa 92% in both WT and APC males, while it had no effect in females (p < 0.05). Leucine had no effect on regulators of protein balance and myogenesis in either sex. We demonstrated that leucine exacerbates moribundity in males and is not sufficient for mitigating muscle or fat loss during CC in either sex in the ApcMin/+ mouse.

Development and Characterization of a Cancer Cachexia Rat Model Transplanted with Cells of the Rat Lung Adenocarcinoma Cell Line Sato Lung Cancer (SLC)

Cancer cachexia is a complex malnutrition syndrome that causes progressive dysfunction. This syndrome is accompanied by protein and energy losses caused by reduced nutrient intake and the development of metabolic disorders. As many as 80% of patients with advanced cancer develop cancer cachexia; however, an effective targeted treatment remains to be developed. In this study, we developed a novel rat model that mimics the human pathology during cancer cachexia to elucidate the mechanism underlying the onset and progression of this syndrome. We subcutaneously transplanted rats with SLC cells, a rat lung adenocarcinoma cell line, and evaluated the rats' pathophysiological characteristics. To ensure that our observations were not attributable to simple starvation, we evaluated the characteristics under tube feeding. We observed that SLC-transplanted rats exhibited severe anorexia, weight loss, muscle atrophy, and weakness. Furthermore, they showed obvious signs of cachexia, such as anemia, inflammation, and low serum albumin. The rats also exhibited weight and muscle losses despite sufficient nutrition delivered by tube feeding. Our novel cancer cachexia rat model is a promising tool to elucidate the pathogenesis of cancer cachexia and to conduct further research on the development of treatments and supportive care for patients with this disease.

Muscle and Adipose Wasting despite Disease Control: Unaddressed Side Effects of Palliative Chemotherapy for Pancreatic Cancer

Muscle and adipose wasting during chemotherapy for advanced pancreatic cancer (aPC) are associated with poor outcomes. We aimed to quantify the contributions of chemotherapy regimen and tumour progression to muscle and adipose wasting and evaluate the prognostic value of each tissue loss. Of all patients treated for aPC from 2013-2019 in Alberta, Canada (n = 504), computed-tomography (CT)-defined muscle and adipose tissue index changes (∆SMI, ∆ATI, cm2/m2) were measured for patients with CT images available both prior to and 12 ± 4 weeks after chemotherapy initiation (n = 210). Contributions of regimen and tumour response to tissue change were assessed with multivariable linear regression. Survival impacts were assessed with multivariable Cox's proportional hazards models. Tissue changes varied widely (∆SMI: -17.8 to +7.3 cm2/m2, ∆ATI: -106.1 to +37.7 cm2/m2) over 116 (27) days. Tumour progression contributed to both muscle and adipose loss (-3.2 cm2/m2, p < 0.001; -12.4 cm2/m2, p = 0.001). FOLFIRINOX was associated with greater muscle loss (-1.6 cm2/m2, p = 0.013) and GEM/NAB with greater adipose loss (-11.2 cm2/m2, p = 0.002). The greatest muscle and adipose losses were independently associated with reduced survival (muscle: HR 1.72, p = 0.007; adipose: HR 1.73, p = 0.012; tertile 1 versus tertile 3). Muscle and adipose losses are adverse effects of chemotherapy and may require regimen-specific management strategies.