CNTO 328, a monoclonal antibody to IL-6, inhibits human tumor-induced cachexia in nude mice

Disruption of MEF2C signaling and loss of sarcomeric and mitochondrial integrity in cancer-induced skeletal muscle wasting

Cancer cachexia is a highly debilitating paraneoplastic disease observed in more than 50% of patients with advanced cancers and directly contributes to 20% of cancer deaths. Loss of skeletal muscle is a defining characteristic of patients with cancer cachexia and is associated with poor survival. The present study reveals the involvement of a myogenic transcription factor Myocyte Enhancer Factor (MEF) 2C in cancer-induced skeletal muscle wasting. Increased skeletal muscle mRNA expression of Suppressor of Cytokine Signaling (Socs) 3 and the IL-6 receptor indicative of active IL-6 signaling was seen in skeletal muscle of mice bearing the Colon 26 (C26) carcinoma. Loss of skeletal muscle structural integrity and distorted mitochondria were also observed using electron microscopy. Gene and protein expression of MEF2C was significantly downregulated in skeletal muscle from C26-bearing mice. MEF2C gene targets myozenin and myoglobin as well as myokinase were also altered during cachexia, suggesting dysregulated oxygen transport capacity and ATP regeneration in addition to distorted structural integrity. In addition, reduced expression of calcineurin was observed which suggested a potential pathway of MEF2C dysregulation. Together, these effects may limit sarcomeric contractile ability and also predispose skeletal muscle to structural instability; associated with muscle wasting and fatigue in cachexia.

IL-6/IL-6R as a potential key signaling pathway in prostate cancer development

Interleukin-6 (IL-6) is a pleiotropic cytokine involved in prostate regulation and in prostate cancer (PC) development/progression. IL-6 acts as a paracrine and autocrine growth stimulator in benign and tumor prostate cells. The levels of IL-6 and respective receptors are increased during prostate carcinogenesis and tumor progression. Several studies reported that increased serum and plasma IL-6 and soluble interleukin-6 receptor levels are associated with aggressiveness of the disease and are associated with a poor prognosis in PC patients. In PC treatment, patients diagnosed with advanced stages are frequently submitted to hormonal castration, although most patients will eventually fail this therapy and die from recurrent castration-resistant prostate cancer (CRPC). Therefore, it is important to understand the mechanisms involved in CRPC. Several pathways have been proposed to be involved in CRPC development, and their understanding will improve the way to more effective therapies. In fact, the prostate is known to be dependent, not exclusively, on androgens, but also on growth factors and cytokines. The signaling pathway mediated by IL-6 may be an alternative pathway in the CRPC phenotype acquisition and cancer progression, under androgen deprivation conditions. The principal goal of this review is to evaluate the role of IL-6 pathway signaling in human PC development and progression and discuss the interaction of this pathway with the androgen recepto pathway. Furthermore, we intend to evaluate the inclusion of IL-6 and its receptor levels as a putative new class of tumor biomarkers.The IL-6/IL-6R signaling pathway may be included as a putative molecular marker for aggressiveness in PC and it may be able to maintain tumor growth through the AR pathway under androgen-deprivation conditions. The importance of the IL-6/IL-6R pathway in regulation of PC cells makes it a good candidate for targeted therapy.

Effect of thymosin alpha-1 on subpopulations of Th1, Th2, Th17, and regulatory T cells (Tregs) in vitro

Thymosin alpha 1 (Tα1) has been shown to have beneficial effects on numerous immune system parameters, but little is known about the effects of Tα1 on patients with gastric carcinoma. The objective of this study was to determine the effect of Tα1 on subpopulations of Th1, Th2, Th17, and regulatory T cells (Tregs) in vitro, and to evaluate its efficacy as an immunoregulatory factor in patients with gastric carcinoma. We compared the effect of Tα1 on the frequency of CD4+ and CD8+ T cells, especially the CD4+CD25+Foxp3+ Tregs in peripheral blood mononuclear cells (PBMCs) from gastric carcinoma patients (N = 35) and healthy donors (N = 22). We also analyzed the changes in the proliferation of PBMCs in response to treatment with Tα1, and examined the production of Th1, Th2, and Th17 cytokines by PBMCs and tumor-infiltrating lymphocytes. The treatment of PBMCs from gastric cancer patients, with Tα1 (50 µg/mL) alone increased the percentage of CD4+CD25+Foxp3+ (suppressive antitumor-specific Tregs) from 1.68 ± 0.697 to 2.19 ± 0.795% (P < 0.05). Our results indicate that Tα1 increases the percentage of Tregs and IL-1β, TNF-α, and IL-6 in vitro.

The anti-interleukin-6 antibody siltuximab down-regulates genes implicated in tumorigenesis in prostate cancer patients from a phase I study

BACKGROUND

Interleukin-6 (IL-6) is associated with prostate cancer morbidity. In several experimental models, IL-6 has been reported to have anti-apoptotic and pro-angiogenic effects. Siltuximab (CNTO 328) is a monoclonal anti-IL-6 antibody which has been successfully applied in several models representing prostate cancer. This study was designed to assess preliminary safety of siltuximab in patients with early prostate cancer.

PATIENTS AND METHODS

Twenty patients scheduled to undergo radical prostatectomy received either no drug or siltuximab (6 mg/kg, five patients per group with administration once, two times, and three times prior to surgery). Blood samples were collected for pharmacokinetic and pharmacodynamic analyses. Expression of elements of IL-6 signaling pathways was analyzed in tumor tissue by immunohistochemistry. Gene analysis in tumor specimens was performed with the DASL array.

RESULTS

No adverse events related to siltuximab were observed. Patients treated with siltuximab presented with higher levels of proliferation and apoptosis markers. Following a single dose, serum concentrations of siltuximab declined in a biexponential manner. This study revealed a decrease in phosphorylation of Stat3 and p44/p42 mitogen-activated protein kinases. In addition, gene expression analyses indicate down-regulation of genes immediately downstream of the IL-6 signaling pathway and key enzymes of the androgen signaling pathway.

CONCLUSIONS

Preliminary safety of siltuximab is favorable. Future studies in which siltuximab could be combined with androgen-deprivation therapy and experimental therapies in advanced prostate cancer are justified.

Anti-inflammatory therapies in cancer cachexia

Disease progression in cancer is dependent on the complex interaction between the tumor and the host inflammatory response. Indeed, both the tumor and the patient produce cytokines that act on multiple target sites such as bone marrow, myocytes, hepatocytes, adipocytes, endothelial cells and neurons, where they produce a complex cascade of biological responses leading to the wasting associated with cachexia. The cytokines that have been involved in this cachectic response are TNF-alpha, IL-1, IL-6 and interferon-gamma. Interestingly, these cytokines share the same metabolic effects and their activities are closely interrelated. In many cases these cytokines exhibit synergic effects when administered together. Therefore, therapeutic strategies - either nutritional or pharmacological - have been based on either blocking their synthesis or their action.

Clinical significance of interleukin (IL)-6 in cancer metastasis to bone: potential of anti-IL-6 therapies

Metastatic events to the bone occur frequently in numerous cancer types such as breast, prostate, lung, and renal carcinomas, melanoma, neuroblastoma, and multiple myeloma. Accumulating evidence suggests that the inflammatory cytokine interleukin (IL)-6 is frequently upregulated and is implicated in the ability of cancer cells to metastasize to bone. IL-6 is able to activate various cell signaling cascades that include the STAT (signal transducer and activator of transcription) pathway, the PI3K (phosphatidylinositol-3 kinase) pathway, and the MAPK (mitogen-activated protein kinase) pathway. Activation of these pathways may explain the ability of IL-6 to mediate various aspects of normal and pathogenic bone remodeling, inflammation, cell survival, proliferation, and pro-tumorigenic effects. This review article will discuss the role of IL-6: 1) in bone metabolism, 2) in cancer metastasis to bone, 3) in cancer prognosis, and 4) as potential therapies for metastatic bone cancer.

IL-6 causes multiple effects in androgen-sensitive and -insensitive prostate cancer cell lines

The androgen receptor (AR) is expressed in most human prostate cancers. It can be activated in a hypersensitive manner by androgens, nonandrogenic steroids, nonsteroidal anti-androgens and in a ligand-independent manner. IL-6 is a proinflammatory cytokine that activates several signaling pathways. It can either stimulate or inhibit growth of prostate cancer cells. IL-6 is an important positive regulator of AR activity and can stimulate the expression of prostate-specific antigen in a ligand-independent manner. IL-6/AR interaction may either result in growth stimulation (MDA PCa 2b cells) or inhibition (LAPC-4 cells). IL-8 and IL-4 have also been observed to activate AR. Cells generated by prolonged treatment with IL-6 acquire a growth advantage. There are several therapeutic options to target IL-6 in prostate cancer and most laboratory studies have been performed with the monoclonal antibody siltuximab. Endogenous suppressors of cytokine signaling (SOCS)-3 and -1 are expressed in prostate cancer tissue. SOCS-3 inhibits apoptosis in AR-negative cells. However, in androgen-sensitive prostate cancer cell lines, SOCS-3 is induced by androgen and blocks its effects on proliferation and secretion. It is currently understood that there are numerous interactions between androgen and IL-6 signaling in human prostate cancer.

Interleukin 6 as a key regulator of muscle mass during cachexia

Interleukin 6 (IL-6) has received significant attention for its regulatory role in muscle wasting during cachexia. This review examines the role of circulating IL-6 for decreasing muscle mass during cancer and emphasizes some of the indirect actions of IL-6 that may cause muscle wasting.

Consistent interactions between tumor cell IL-6 and macrophage TNF-α enhance the growth of human prostate cancer cells in the bone of nude mouse

To test the hypothesis that tumor-associated macrophages (TAMs) enhance the growth and metastasis of human prostate cancer in the bone, we evaluated the effects of decreasing interleukin-6 (IL-6) production by tumor cells and TAMs in a mouse model of bone metastasis. Human PC-3MM2 cells that produce IL-6 were transfected with lentivirus containing IL-6 small hairpin RNA (shRNA) or nonspecific RNA and injected into the tibias of nude mice treated intraperitoneally every 5days for 5weeks with phosphate-buffered saline (PBS), liposomes containing PBS, or liposomes containing clodronate (to decrease the number of macrophages). Transfection of PC-3MM2 cells with IL-6 shRNA significantly decreased cellular expression of IL-6 and the number of TAMs and osteoclasts in bone tumors, which correlated with significant decreases in tumor size, bone lysis, and incidence of lymph node metastasis. Treatment of mice with clodronate liposomes significantly decreased the number of TAMs and osteoclasts in the bone tumors, the expression of IL-6 in the PC3-MM2 cells, and the production of tumor necrosis factor (TNF)-α by TAMs. These findings correlated with a significant decrease in tumor size, bone lysis, and lymph node metastasis. Knocking down IL-6 in tumor cells and decreasing TAMs was associated with the lowest incidences of bone tumors and lymph node metastasis. These results suggest that TAMs enhance the growth of prostate cancer cells in the bone.

A phase I/II study of siltuximab (CNTO 328), an anti-interleukin-6 monoclonal antibody, in metastatic renal cell cancer

Background:

Serum interleukin (IL)-6 levels correlate with disease outcomes in renal cell carcinoma (RCC) patients. Siltuximab, a chimeric, murine-human mAb against IL-6, was evaluated in a three-part phase I/II study in patients with progressive metastatic RCC.

Methods:

In part 1, 11 patients received 1, 3, 6, or 12 mg kg^–1 at weeks 1, 4 and q2w × 2 thereafter; in part 2, 37 patients randomly received 3 or 6 mg kg^–1 q3w × 4; in part 3, 20 low-risk patients received 6 mg kg^–1 q2w × 6. Modified WHO response criteria were assessed at weeks 7, 11, the 6-week follow-up, and when clinically indicated.

Results:

Siltuximab was well tolerated overall, with no maximum tolerated dose or immune response observed. In all, 5 out of 11, 17 out of 37, and 9 out of 20 patients in parts 1, 2, and 3, respectively, received extended treatment beyond 4–6 initial infusions. In part 2, stable disease (SD) (⩾11weeks) or better was achieved by 11 out of 17 (65%) 3 mg kg^–1 treated patients (one partial response (PR) ∼8 months, 10 SD) and 10 out of 20 (50%) 6 mg kg^–1 treated patients (10 SD). In part 3, documented complete or PR was not observed, but 13 out of 20 (65%) patients achieved SD.

Conclusion:

Siltuximab stabilised disease in >50% of progressive metastatic RCC patients. One PR was observed. Given the favourable safety profile of siltuximab and poor correlation of tumour shrinkage with clinical benefit demonstrated for other non-cytotoxic therapies, further evaluation of dose-escalation strategies and/or combination therapy may be considered for patients with RCC.

Effects of siltuximab on the IL-6-induced signaling pathway in ovarian cancer

PURPOSE

To explore potential therapeutic strategies for interrupting the interleukin-6 (IL-6) signaling pathway, we measured IL-6 expression in ovarian cancer tissues, and evaluated the effects of a monoclonal anti-IL-6 antibody; siltuximab (CNTO 328), on levels of IL-6-induced Stat3 phosphorylation, Stat3 nuclear translocation, and Stat3 downstream antiapoptotic genes. We then looked for enhancing paclitaxel sensitivity in multidrug-resistant ovarian cancer cell lines.

EXPERIMENTAL DESIGN

Expressions of IL-6 in ovarian cancer patient specimens were assessed by immunohistochemistry. Effects of siltuximab on IL-6-induced activation of Stat3 in an ovarian cancer cell line were determined by Western blot and real-time analysis of Stat3 nucleocytoplasmic translocation. Influence of combination of siltuximab and paclitaxel on tumor growth was evaluated in a xenograft mouse mode in vivo.

RESULTS

Metastatic and drug-resistant recurrent tumors have significantly higher IL-6 expression when compared with the matched primary tumors. Siltuximab specifically suppressed IL-6-induced Stat3 phosphorylation and Stat3 nuclear translocation. Treatment with siltuximab significantly decreased the levels of Stat3 downstream proteins such as MCL-1, Bcl-X(L), and survivin. Treatment with siltuximab reduced expression of multiple IL-6-induced genes in these cell lines. Furthermore, siltuximab increased the cytotoxic effects of paclitaxel in a paclitaxel resistant ovarian cancer cell line in vitro, but combination therapy with siltuximab did not have a significant effect on paclitaxel resistant tumor growth in vivo.

CONCLUSIONS

These results show that siltuximab effectively block the IL-6 signaling pathways and IL-6-induced gene expression. Blockage of IL-6 signaling may provide benefits for the treatment of ovarian cancer.

Interleukin-6 in bone metastasis and cancer progression

The bone and bone marrow are among the most frequent sites of cancer metastasis. It is estimated that 350,000 patients die with bone metastases annually in the United States. The ability of tumor cells to colonize the bone marrow and invade the bone is the result of close interactions between tumor cells and the bone marrow microenvironment. In this article, we review the contribution of interleukin-6 (IL-6) produced in the bone marrow microenvironment to bone metastasis. This cytokine has a strong pro-tumorigenic activity due to its multiple effects on bone metabolism, tumor cell proliferation and survival, angiogenesis, and inflammation. These effects are mediated by several signaling pathways, in particular the Janus kinase/signal transducer and transcription activator (JAK/STAT-3), Ras/mitogen activated protein kinase (MAPK), and phosphoinositol-3 kinase (PI3K)-protein kinase B/Akt (PkB/Akt), which are activated by IL-6 and amplified in the presence of soluble IL-6 receptor (sIL-6R). Supporting the role of IL-6 in human cancer is the observation of elevated serum levels of IL-6 and sIL-6R in patients with bone metastasis and their association with a poor clinical outcome. Over the last decade several large (monoclonal antibodies) and small (inhibitors of IL-6 mediated signaling) molecules that inhibit IL-6 activity in preclinical models have been developed. Several of these inhibitors are now undergoing phases I and II clinical trials, which will determine their inclusion in the list of effective targeted agents in the fight against cancer.

New insights into adipose tissue atrophy in cancer cachexia

Profound loss of adipose and other tissues is a hallmark of cancer cachexia, a debilitating condition associated with increased morbidity and mortality. Fat loss cannot be attributable to reduced appetite alone as it precedes the onset of anorexia and is much more severe in experimental models of cachexia than in food restriction. Morphological examination has shown marked remodelling of adipose tissue in cancer cachexia. It is characterised by the tissue containing shrunken adipocytes with a major reduction in cell size and increased fibrosis in the tissue matrix. The ultrastructure of 'slimmed' adipocytes has revealed severe delipidation and modifications in cell membrane conformation. Although the molecular mechanisms remain to be established, evidence suggests that altered adipocyte metabolism may lead to adipose atrophy in cancer cachexia. Increased lipolysis appears to be a key factor underlying fat loss, while inhibition of adipocyte development and lipid deposition may also contribute. Both tumour and host-derived factors are implicated in adipose atrophy. Zinc-alpha2-glycoprotein (ZAG), which is overexpressed by certain malignant tumours, has been identified as a novel adipokine. ZAG transcripts and protein expression in adipose tissue are up regulated in cancer cachexia but reduced with adipose tissue expansion in obesity. Studies in vitro demonstrate that recombinant ZAG stimulates lipolysis. ZAG may therefore act locally, as well as systemically, to promote lipid mobilisation in cancer cachexia. Further elucidation of ZAG function in adipose tissue may lead to novel targets for preventing adipose atrophy in malignancy.

Engineering therapeutic monoclonal antibodies

During last two decades, the chimerization and humanization of monoclonal antibodies (mAbs) have led to the approval of several for the treatment of cancer, autoimmune diseases, and transplant rejection. Additional approaches have been used to further improve their in vivo activity. These include combining them with other modalities such as chemotherapy and redesigning them for improved pharmacokinetics, effector function, and signaling activity. The latter has taken advantage of new insights emerging from an increased understanding of the cellular and molecular mechanisms that are involved in the interaction of immunoglobulin G with Fc receptors and complement as well as the negative signaling resulting from the hypercrosslinking of their target antigens. Hence, mAbs have been redesigned to include mutations in their Fc portions, thereby endowing them with enhanced or decreased effector functions and more desirable pharmacokinetic properties. Their valency has been increased to decrease their dissociation rate from cells and enhance their ability to induce apoptosis and cell cycle arrest. In this review we discuss these redesigned mAbs and current data concerning their evaluation both in vitro and in vivo.

The biological mechanisms of cancer-related skeletal muscle wasting: the role of progressive resistance exercise

Cancer results in perturbations in skeletal muscle protein metabolism leading to muscle wasting. Although severe wasting is seen primarily in persons with advanced malignancies, a number of cancer patients show some degree of wasting at presentation. Although cancer-related skeletal muscle wasting is attributable, in part, to decreased muscle protein synthesis, its primary cause appears to be increased muscle protein degradation. Although several proteolytic systems may be involved, compelling evidence suggests that the major system responsible for skeletal muscle protein degradation in cancer is the ATP-dependent ubiquitin- proteasome system. Other contributing factors include proinflammatory cytokines and the tumor-released proteolysis-inducing factor. Decreased physical activity and decreased nutritional intake may also play a role. Cancer-related skeletal muscle wasting is clinically significant because of its profound effects on functional outcomes and quality of life. Nevertheless, no specific interventions have proved to be effective in preventing or reversing the problem. Interventions such as nutritional supplementation and appetite stimulants are only partially helpful. A nonpharmacologic intervention that may attenuate cancer-related skeletal muscle wasting is progressive resistance exercise training (PRT). PRT is a potent stimulus of growth in muscle mass and strength. PRT may attenuate cancer-related skeletal muscle wasting by downregulating the activity of proinflammatory cytokines and by increasing the phosphorylation of intramuscular amino acid-signaling molecules. This article discusses several cancer-related skeletal muscle wasting mechanisms and proposes how PRT might attenuate muscle wasting by counteracting some of these mechanisms.

Muscle wasting and interleukin-6-induced atrogin-I expression in the cachectic Apc ( Min/+ ) mouse

Interleukin-6 (IL-6) is necessary for cachexia in Apc ( Min/+ ) mice, but the mechanisms inducing this myofiber wasting have not been established. The purpose of this study was to examine gastrocnemius muscle wasting in the Apc ( Min/+ ) mouse and to determine IL-6 regulated mechanisms contributing to muscle loss. Gastrocnemius type IIB mean fiber cross-sectional area (CSA) from Apc ( Min/+ ) mice decreased 32% between 13 and 22 weeks of age. Apc ( Min/+ ) mice lacking IL-6 did not have type IIB fiber atrophy, while overexpression of circulating IL-6 exacerbated the loss of type IIB fiber CSA in Apc ( Min/+ ) mice. Muscle Atrogin-I mRNA expression was induced at least ninefold at 18 and 22 weeks of age compared to 13-week-old mice. Atrogin-I gene expression was also induced by overexpression of circulating IL-6. These data suggest that high circulating IL-6 levels induce type IIB fiber CSA loss in Apc ( Min/+ ) mice, and circulating IL-6 is sufficient to regulate Atrogin-I gene expression in cachectic mice.

Regulation of adipose tissue metabolism in cancer cachexia

PURPOSE OF REVIEW

Body-fat depletion is a hallmark of cancer cachexia, a complex clinical syndrome associated with increased morbidity and mortality. Understanding the fat-loss disorder in cachexia is essential for the development of better treatments for the syndrome. This review presents recent studies focusing on the mechanisms of adipose atrophy in cancer cachexia, particularly the potential mediators.

RECENT FINDINGS

Fat loss cannot be explained by poor appetite alone, and may also result from altered lipid metabolism in adipocytes. Increased lipolysis appears to be a key factor underlying fat loss in cancer cachexia though decreases in lipid deposition and adipocyte development may also contribute. Both tumour and host-derived factors are implicated in adipose tissue atrophy. Tumour necrosis factor-alpha has been associated with increased lipolysis in adipocytes. The novel adipokine zinc-alpha2-glycoprotein may function locally, as well as systemically, to promote lipid mobilization and utilization in cancer cachexia.

SUMMARY

Clarifying the role of cachexia mediators in adipose tissue atrophy will add to our understanding of adipocyte metabolism in wasting disease. Elucidating their mode of action may lead to novel therapeutic targets for counteracting the cachexia syndrome.

IL-6 involvement in epithelial cancers

In this issue of the JCI, two reports provide intriguing new information on the role of the inflammatory cytokine IL-6 in breast and lung cancer. The study by Sansone et al. implicates IL-6 in the instigation of malignant properties in breast cancer stem cells (see the related article beginning on page 3988). The study by Gao et al. identifies mutant variants of EGFR as inducers of IL-6 in lung adenocarcinomas (see the related article beginning on page 3846). These studies add to our understanding of potential roles for IL-6 in cancer and further motivate investigations of IL-6-targeted chemotherapeutics.

Role of gp130-mediated signalling pathways in the heart and its impact on potential therapeutic aspects

IL-6-type cytokines bind to plasma membrane receptor complexes containing the common signal transducing receptor chain gp130 that is ubiquitously expressed in most tissues including the heart. The two major signalling cascades activated by the gp130 receptor, SHP2/ERK and STAT pathways, have been demonstrated to play important roles in cardiac development, hypertrophy, protection and remodelling in response to physiological and pathophysiological stimuli. Experimental data, both in vivo and in vitro, imply beneficial effects of gp130 signalling on cardiomyocytes in terms of growth and survival. In contrast, it has been reported that elevated serum levels of IL-6 cytokines and gp130 proteins are strong prognostic markers for morbidity and mortality in patients with heart failure or after myocardial infarction. Moreover, it has been shown that the local gp130 receptor system is altered in failing human hearts. In the present review, we summarize the basic principles of gp130 signalling, which requires simultaneous activation of STAT and ERK pathways under the tight control of positive and negative intracellular signalling modulators to provide a balanced biological outcome. Furthermore, we highlight the key role of the gp130 receptor and its major downstream effectors in the heart in terms of development and regeneration and in response to various physiological and pathophysiological stress situations. Finally, we comment on tissue-specific diversity and challenges in targeted pharmacological interference with components of the gp130 receptor system.

Defining cancer cachexia in head and neck squamous cell carcinoma

PURPOSE

Cancer cachexia is a devastating and understudied illness in patients with head and neck squamous cell carcinoma (HNSCC). The primary objective was to identify clinical characteristics and serum levels of cytokines and cachexia-related factors in patients with HNSCC. The secondary objective was to detect the occurrence of cytokine and cachexia-related factor gene expression in HNSCC tumors.

EXPERIMENTAL DESIGN

For the primary objective, cross-sectional data were obtained from prospectively recruited patients identified as cachexia cases and matching cachexia-free controls. For the secondary objective, a retrospective cohort design with matched controls was used.

RESULTS

Clinical characteristics associated with cancer cachexia in HNSCC were T(4) status (P = 0.01), increased C-reactive protein (P = 0.01), and decreased hemoglobin (P < 0.01). Exploratory multiplex analysis of serum cytokine levels found increased interleukin (IL)-6 (P = 0.04). A highly sensitive ELISA confirmed the multiplex result for increased IL-6 in cachectic patients (P = 0.02). Quality of life was substantially reduced in patients with cachexia compared with noncachectic patients (P < 0.01). All tumors of HNSCC patients both with and without cachexia expressed RNA for each cytokine tested and the cachexia factor lipid-mobilizing factor. There were no statistically significant differences between the cytokine and cachexia factor RNA expression of cachectic and noncachectic patients (each P > 0.05). No tumors expressed the cachexia factor proteolysis-inducing factor.

CONCLUSION

We have identified clinical characteristics and pathophysiologic mechanisms associated with cancer cachexia in a carefully defined population of patients with HNSCC. The data suggest that the acute-phase response and elevated IL-6 are associated with this complex disease state. We therefore hypothesize that IL-6 may represent an important therapeutic target for HNSCC patients with cancer cachexia.

Interleukin-6 and its receptor in cancer: implications for translational therapeutics

Interleukin-6 (IL-6) plays a major role in the response to injury or infection and is involved in the immune response, inflammation, and hematopoiesis. Its deregulation impacts numerous disease states, including many types of cancer. Consequently, modulating IL-6 may be an innovative therapeutic strategy in several diseases. A review of relevant published literature regarding IL-6 and its receptor was performed. In addition, a review of the relevance of this cytokine system to human illness, particularly in cancer, was undertaken. IL-6 is a pleiotropic cytokine that is involved in the physiology of virtually every organ system. Aberrant expression of this cytokine has been implicated in diverse human illnesses, most notably inflammatory and autoimmune disorders, coronary artery and neurologic disease, gestational problems, and neoplasms. In cancer, high levels of circulating IL-6 are observed in almost every type of tumor studied and predict a poor outcome. Furthermore, elevated IL-6 levels are associated strongly with several of the striking phenotypic features of cancer. Several molecules have been developed recently that target the biologic function of IL-6. Early results in the clinic suggest that this strategy may have a significant salutary impact on diverse tumors. The field of cytokine research has yielded a deep understanding of the fundamental role of IL-6 and its receptor in health and disease. Therapeutic targeting of IL-6 and its receptor in cancer has strong biologic rationale, and there is preliminary evidence suggesting that targeting of the IL-6 system may be beneficial in the treatment of cancer.

Interleukin-6 and cachexia in ApcMin/+ mice

The Apc(Min/+) mouse has a mutation in the Apc tumor suppressor gene and develops intestinal polyps, beginning at 4 wk of age. This mouse develops cachexia by 6 mo, characterized by significant loss of muscle and fat tissue. The purpose of the present study was to determine the role of circulating interleukin-6 (IL-6) and the polyp burden for the development of cachexia in Apc(Min/+) mice. At 26 wk of age, mice exhibiting severe cachectic symptoms had a 61% decrease in gastrocnemius muscle weight, complete loss of epididymal fat, a 10-fold increase in circulating IL-6 levels, and an 89% increase in intestinal polyps compared with mildly cachectic animals. Apc(Min/+)/IL-6(-/-) mice did not lose gastrocnemius muscle mass or epididymal fat pad mass while overall polyp number decreased by 32% compared with Apc(Min/+) mice. Plasmid-based IL-6 overexpression in Apc(Min/+)/IL-6(-/-) mice led to a decrease in gastrocnemius muscle mass and epididymal fat pad mass and increased intestinal polyp burden. IL-6 overexpression did not induce cachexia in non-tumor-bearing mice. These data demonstrate that IL-6 is necessary for the onset of adipose and skeletal muscle wasting in the Apc(Min/+) mouse and that circulating IL-6 can regulate Apc(Min/+) mouse tumor burden.

Cancer cachexia syndrome in head and neck cancer patients: part I. Diagnosis, impact on quality of life and survival, and treatment

BACKGROUND

Cancer cachexia is a debilitating, wasting condition that affects many cancer patients, including those with head and neck cancer. The overall incidence of cancer cachexia is quite high for some types of cancer, and cachexia will be the main cause of death for more than 20% of all cancer patients. This syndrome uniquely challenges patients with head and neck cancer. This article outlines the diagnosis of cancer cachexia, reviews its impact on patient quality of life (QOL) and survival, and updates the reader on potential therapies that may suppress it.

METHODS

A comprehensive literature search was performed using PubMed of the National Library of Medicine, which includes more than 15 million citations back to the 1950s. The Cochrane Library and Google search engine were used as well.

RESULTS

This syndrome differs significantly from starvation, and thus accurate and timely diagnosis is essential. Nutritional therapy alone is insufficient. Current management strategies include corticosteroids and megesterol acetate, in conjunction with nutritional therapy. Future strategies may include nutraceuticals, omega-3 fatty acids, inflammatory antagonists, and other targeted treatments.

CONCLUSIONS

Because cancer cachexia differs significantly from starvation, nutritional supplementation must be used in conjunction with other anti-cachexia agents to reverse the chronic systemic inflammatory state and the effects of circulating tumor-derived factors seen in cachexia. Careful identification of patients at risk and those suffering from this syndrome will lead to better outcomes and treatments. Ultimately, more research is needed to better treat this devastating condition.

Interleukin 6 is associated with cachexia in patients with prostate cancer

OBJECTIVES

To evaluate the relationship between serum interleukin (IL)-6 and cachexia in patients with prostate cancer.

METHODS

Serum levels of IL-6, total protein, albumin, total cholesterol, and hemoglobin concentration were determined in 164 blood samples from patients with prostate cancer. The body mass index and performance status were also determined.

RESULTS

The serum total protein, albumin, and cholesterol levels, hemoglobin levels, and body mass index of the patients whose serum IL-6 level was 7 pg/mL or greater were significantly lower (P <0.05) than the corresponding values in patients with a serum IL-6 level of less than 7 pg/mL. The serum IL-6 level of patients with a serum albumin level of less than 3.5 g/dL, serum total protein level of less than 7.0 g/dL, serum total cholesterol level of less than 180 mg/dL, hemoglobin level of less than 11.0 g/dL, and body mass index of less than 21 kg/m2 were significantly greater (P <0.05) than the values in their respective counterparts. A significant correlation was found between the elevation of serum IL-6 and performance status (P <0.05). The mortality rate of patients with greater serum IL-6 levels was significantly greater than that of those with lower serum IL-6 levels in patients with untreated disease, patients in remission, and patients with relapse (all P <0.05).

CONCLUSIONS

These findings suggest that IL-6 may be one of the factors contributing to the complex syndrome of cachexia in patients with prostate cancer (all P <0.05).

Cancer Chemotherapy-Related Symptoms: Evidence to Suggest a Role for Proinflammatory Cytokines

PURPOSE/OBJECTIVES

To provide an overview of the evidence that supports a role for the proinflammatory cytokines interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), and interleukin-6 (IL-6) in the etiology of cancer chemotherapy-related symptoms.

DATA SOURCES

Electronic nursing, psychology, and medicine databases; online meeting abstracts; and personal experimental observations.

DATA SYNTHESIS

Substantial evidence implicates the proinflammatory cytokines IL-1beta, TNF-alpha, and IL-6 in the etiology of chemotherapy-related anorexia, cachexia, anemia, pain, sleep disturbance, fatigue, and depression.

CONCLUSIONS

Further investigation into the role of these cytokines in the genesis of chemotherapy-related symptoms is warranted. The development of appropriate animal models likely will be key to understanding the relationship among cancer chemotherapy, proinflammatory cytokines, and symptoms.

IMPLICATIONS FOR NURSING

Nurses traditionally have been leaders in symptom management. The symptoms experienced by patients undergoing chemotherapy have a profound negative impact on quality of life and patients' ability to receive prescribed treatments. An understanding of potential mechanisms underlying the physiologic and behavioral consequences of chemotherapy administration will aid nurses in the development of interventions to effectively manage chemotherapy-related symptoms.

Regulation of growth of prostate cancer cells selected in the presence of interleukin-6 by the anti-interleukin-6 antibody CNTO 328

BACKGROUND

Interleukin-6 (IL-6) is a multifunctional regulator of cellular events in prostate cancer. LNCaP-IL-6+ cells selected in the presence of IL-6 were taken for assessment of effects of the chimeric monoclonal anti-IL-6 antibody CNTO 328.

METHODS

Cell viability was assessed after treatment with CNTO 328 by the ATP assay. Expression of Bcl-2 and Bax and activation of signaling pathways were evaluated by Western analysis. Nude mice were inoculated with LNCaP-IL-6+ cells and treated with CNTO 328. The tumors were analyzed by immunohistochemistry for expression of Ki-67, tissue transglutaminase, and vascular endothelial growth factor.

RESULTS

CNTO 328 caused a statistically significant inhibition of cell viability. The protein levels of Bcl-2 and the phosphorylation of ERK1/2 mitogen-activated protein kinases were decreased by the anti-IL-6 antibody. Treatment with CNTO 328 yielded an increase in the phosphorylation of signal transducers and activators of transcription factor 3. The mean tumor volume in animals inoculated with LNCaP-IL-6+ cells and treated with CNTO 328 was insignificantly lower than that in animals treated with the control antibody. There was a statistically significant decrease in the percentage of Ki-67-positive cells in CNTO 328-treated tumors.

CONCLUSION

CNTO 328 has a potential in prostate cancer therapy and could be further tested in various combination experimental treatments.

Inhibition of interleukin-6 with CNTO328, an anti-interleukin-6 monoclonal antibody, inhibits conversion of androgen-dependent prostate cancer to an androgen-independent phenotype in orchiectomized mice

Initially, prostate cancer is androgen dependent. However, most cases progress to an androgen-independent state through unknown mechanisms. Interleukin-6 (IL-6) has been associated with prostate cancer progression including activation of the androgen receptor (AR). To determine if IL-6 plays a role in the conversion of prostate cancer from androgen dependent to androgen independent, we established androgen-dependent LuCaP 35 human prostate cancer xenografts in nude mice, castrated the mice, and blocked IL-6 activity using a neutralizing antibody (CNT0328) for a period of 18 weeks. IL-6 inhibition increased survival of mice and inhibited tumor growth, as reflected by decreased tumor volume and prostate-specific antigen levels, compared with that in mice receiving isotype control antibody. To test the effect of IL-6 inhibition on the conversion from androgen dependent to androgen independent, tumor cells from the treated mice were assessed for their androgen dependence both in vitro and by implanting them into sham-operated or orchiectomized mice. Tumor cells derived from the isotype-treated animals converted to androgen-independent state, whereas tumor cells from the anti-IL-6 antibody-treated mice were still androgen dependent in vitro and in vivo. Although there was no difference in AR levels between the androgen-independent and androgen-dependent tumors, IL-6 inhibition promoted both apoptosis and inhibited cell proliferation in tumors and blocked the orchiectomy-induced expression of histone acetylases, p300 and CBP, which are AR cofactors. These data show that IL-6 contributes to the development of androgen independence in prostate cancer and suggest that it mediates this effect, in part, through modulation of p300 and CBP.

Mediators involved in the cancer anorexia-cachexia syndrome: past, present, and future

The cachectic syndrome, characterized by a marked weight loss, anorexia, asthenia, and anemia is invariably associated with the presence and growth of the tumor and leads to a malnutrition status due to the induction of anorexia or decreased food intake. In addition, the competition for nutrients between the tumor and the host leads to an accelerated starvation state, which promotes severe metabolic disturbances in the host, including hypermetabolism, which leads to an increased energetic inefficiency. Although the search for the cachectic factor(s) started a long time ago, and although many scientific and economic efforts have been devoted to its discovery, we are still a long way from knowing the whole truth. Present investigation is devoted to revealing the different signaling pathways, in particular transcriptional factors involved in muscle wasting. The main aim of the present review is to summarize and evaluate the different molecular mechanisms and catabolic mediators (both humoral and tumoral) involved in cancer cachexia since they may represent targets for future promising clinical investigations.

The pivotal role of cytokines in muscle wasting during cancer

The cachectic syndrome, characterized by a marked weight loss, anorexia, asthenia and anemia, is invariably associated with the presence and growth of the tumour and leads to a malnutrition status due to the induction of anorexia or decreased food intake. In addition, the competition for nutrients between the tumour and the host leads to an accelerated catabolic state, which promotes severe metabolic disturbances in the host, including hypermetabolism, which leads to an increased energetic inefficiency. Although the search for the cachectic factor(s) started a long time ago, and although many scientific and economic efforts have been devoted to its discovery, we are still a long way from knowing the whole truth. Present investigation is devoted to unrevealing the different signaling pathways (particulary transcriptional factors) involved in muscle wasting. The main aim of the present review is to summarize and evaluate the different molecular mechanisms and catabolic mediators involved in cancer cachexia since they may represent targets for future promising clinical investigations.

The science of megestrol acetate delivery: potential to improve outcomes in cachexia

Cachexia, usually defined as the loss of >5% of an individual's baseline bodyweight over 2-6 months, occurs with a number of diseases that includes not only AIDS and advanced cancer but also chronic heart failure, rheumatoid arthritis, chronic obstructive pulmonary disease, Crohn disease, and renal failure. Anorexia is considered a key component of the anorexia-cachexia syndrome. Progestogens, particularly megestrol acetate, are commonly used to treat anorexia-cachexia. The mechanism of action of megestrol is believed to involve stimulation of appetite by both direct and indirect pathways and antagonism of the metabolic effects of the principal catabolic cytokines. Because the bioavailability of megestrol acetate directly affects its efficacy and safety, the formulation was refined to enhance its pharmacokinetics. Such efforts yielded megestrol acetate in a tablet form, followed by a concentrated oral suspension form, and an oral suspension form developed using nanocrystal technology. Nanocrystal technology was designed specifically to optimize drug delivery and enhance the bioavailability of drugs that have poor solubility in water. Megestrol acetate nanocrystal oral suspension is currently under review by the US FDA for the treatment of cachexia in patients with AIDS. Preclinical pharmacokinetic data suggest that the new megestrol acetate formulation has the potential to significantly shorten the time to clinical response and thus may improve outcomes in patients with anorexia-cachexia.

Interleukin-6 regulation of prostate cancer cell growth

Interleukin-6 (IL-6) is involved in regulation of immune reaction and cell growth and differentiation. It causes multifunctional responses ranging from inhibition of proliferation to promotion of cell survival. IL-6 effects may depend on experimental conditions such as passage numbers and serum composition. IL-6 signals in target tissues through the receptor that is composed of the ligand-binding and signal-transducing subunits. IL-6 is expressed in benign and malignant prostate tissue and the levels of the cytokine and its receptor increase during prostate carcinogenesis. IL-6 is considered a positive growth factor for most prostate cells. The only exemption seems to be the LNCaP cell line, in which IL-6 causes growth arrest and induces differentiation function. In contrast, IL-6 acts as an autocrine growth factor in the subline LNCaP-IL-6+ established after chronic treatment with IL-6. IL-6 is a candidate for targeted therapy in prostate cancer because of its association with morbidity. Activation of signaling pathways of Janus kinase/signal transducers and activators of transcription factors, mitogen-activated protein kinase (MAPK), and phosphatidylinositol 3-kinase has been reported in various prostate cancer cell lines. IL-6 and the related cytokine oncostatin M induce activation of the androgen receptor (AR) in the absence of androgen. IL-6 is also involved in regulation of vascular endothelial growth factor expression as well as neuroendocrine differentiation in prostate. Anti-IL-6 antibodies showed an inhibitory effect on the PC-3 xenograft. However, the development of this therapy in prostate cancer is in early stages.

A novel peptide specifically binding to interleukin-6 receptor (gp80) inhibits angiogenesis and tumor growth

Experimental and clinical findings support the essential role of interleukin (IL)-6 in the pathogenesis of various human cancers and provide a rationale for targeted therapeutic investigations. A novel peptide, S7, which selectively binds to IL-6 receptor (IL-6R) alpha chain (gp80) and broadly inhibits IL-6-mediated events, was identified using phage display library screening. The synthetic S7 peptide specifically bound to soluble IL-6R as well as cognate human IL-6R alpha, resulting in a dose-dependent blockade of the interaction between IL-6 and IL-6R alpha. S7 peptide prevents IL-6-mediated survival signaling and sensitizes cervical cancer cells to chemotherapeutic compounds in vitro. The in vitro analysis of antiangiogenic activity showed that S7 peptide substantially inhibits IL-6-induced vascular endothelial growth factor-A expression and angiogenesis in different cancer cell lines. Furthermore, S7 peptide was bioavailable in vivo, leading to a significant suppression of IL-6-induced vascular endothelial growth factor-mediated cervical tumor growth in severe combined immunodeficient mice. These observations show the feasibility of targeting IL-6/IL-6R interaction using the small peptide and highlight its potential in the clinical applications.

The pivotal role of cytokines in muscle wasting during cancer

The cachectic syndrome, characterized by a marked weight loss, anorexia, asthenia and anemia, is invariably associated with the presence and growth of the tumour and leads to a malnutrition status due to the induction of anorexia or decreased food intake. In addition, the competition for nutrients between the tumour and the host leads to an accelerated catabolic state, which promotes severe metabolic disturbances in the host, including hypermetabolism, which leads to an increased energetic inefficiency. Although the search for the cachectic factor(s) started a long time ago, and although many scientific and economic efforts have been devoted to its discovery, we are still a long way from knowing the whole truth. Present investigation is devoted to unrevealing the different signaling pathways (particularly transcriptional factors) involved in muscle wasting. The main aim of the present review is to summarize and evaluate the different molecular mechanisms and catabolic mediators involved in cancer cachexia since they may represent targets for future promising clinical investigations.