Complete remission achieved with single agent CNTO 328, an anti-IL-6 monoclonal antibody, in relapsed and refractory myeloma

Interleukin-6 serves as a critical factor in various cancer progression and therapy

Interleukin-6 (IL-6), a pro-inflammatory cytokine, plays a crucial role in host immune defense and acute stress responses. Moreover, it modulates various cellular processes, including proliferation, apoptosis, angiogenesis, and differentiation. These effects are facilitated by various signaling pathways, particularly the signal transducer and activator of transcription 3 (STAT3) and Janus kinase 2 (JAK2). However, excessive IL-6 production and dysregulated signaling are associated with various cancers, promoting tumorigenesis by influencing all cancer hallmarks, such as apoptosis, survival, proliferation, angiogenesis, invasiveness, metastasis, and notably, metabolism. Emerging evidence indicates that selective inhibition of the IL-6 signaling pathway yields therapeutic benefits across diverse malignancies, such as multiple myeloma, prostate, colorectal, renal, ovarian, and lung cancers. Targeting key components of IL-6 signaling, such as IL-6Rs, gp130, STAT3, and JAK via monoclonal antibodies (mAbs) or small molecules, is a heavily researched approach in preclinical cancer studies. The purpose of this study is to offer an overview of the role of IL-6 and its signaling pathway in various cancer types. Furthermore, we discussed current preclinical and clinical studies focusing on targeting IL-6 signaling as a therapeutic strategy for various types of cancer.

Emerging roles for the IL-6 family of cytokines in pancreatic cancer

Pancreatic cancer has one of the poorest prognoses of all malignancies, with little improvement in clinical outcome over the past 40 years. Pancreatic ductal adenocarcinoma is responsible for the vast majority of pancreatic cancer cases, and is characterised by the presence of a dense stroma that impacts therapeutic efficacy and drives pro-tumorigenic programs. More specifically, the inflammatory nature of the tumour microenvironment is thought to underlie the loss of anti-tumour immunity and development of resistance to current treatments. Inflammatory pathways are largely mediated by the expression of, and signalling through, cytokines, chemokines, and other cellular messengers. In recent years, there has been much attention focused on dual targeting of cancer cells and the tumour microenvironment. Here we review our current understanding of the role of IL-6, and the broader IL-6 cytokine family, in pancreatic cancer, including their contribution to pancreatic inflammation and various roles in pancreatic cancer pathogenesis. We also summarise potential opportunities for therapeutic targeting of these pathways as an avenue towards combating poor patient outcomes.

The role of the interleukin (IL)-6/IL-6 receptor axis in cancer

Interleukin-6 (IL-6) is a pleiotropic cytokine that activates a classic signalling pathway upon binding to its membrane-bound receptor (IL-6R). Alternatively, IL-6 may 'trans-signal' in a manner that is facilitated by its binding to a soluble derivative of the IL-6 receptor (sIL-6R). Resultant signal transduction is, respectively, driven by the association of IL-6/IL-6R or IL-6/sIL-6R complex with the membrane-associated signal transducer, gp130 (Glycoprotein 130). Distinct JAK (Janus tyrosine kinase)/STAT (signal transducers and activators of transcription) and other signalling pathways are activated as a consequence. Of translational relevance, overexpression of IL-6 has been documented in several neoplastic disorders, including but not limited to colorectal, ovarian and breast cancer and several haematological malignancies. This review attempts to summarise our current understanding of the role of IL-6 in cancer development. In short, these studies have shown important roles for IL-6 signalling in tumour cell growth and survival, angiogenesis, immunomodulation of the tumour microenvironment, stromal cell activation, and ultimate disease progression. Given this background, we also consider the potential for therapeutic targeting of this system in cancer.

IL-6 family cytokines: Key inflammatory mediators as biomarkers and potential therapeutic targets

IL-6 is a critical cytokine in acute phase response and involved in the pathogenesis of several chronic inflammatory diseases including cancer. Studies have highlighted that levels of IL-6 and its family members can be useful for diagnosis, prognosis of relapse-free survival and recurrence. IL-6 family cytokines have been identified as cancer biomarkers through screening of inflammatory mediators in different fluids including saliva, serum, and bronchoalveolar lavage fluid (BALF). IL-6 can be modulated by chemopreventive drugs, small molecules, monoclonal antibodies and immune checkpoint inhibitors. Unveiling the different sources of IL-6, the interaction between IL-6 and its cellular targets, the IL-6-dependent tumor resistance mechanisms, and the identification of novel regulators of IL-6 are some of the highly complex topics included in this review and their understanding could aid cancer biomarkers and therapy development.

Potential therapeutic implications of IL-6/IL-6R/gp130-targeting agents in breast cancer

Interleukin-6 (IL-6) is a pleiotropic cytokine with known multiple functions in immune regulation, inflammation, and oncogenesis. Binding of IL-6 to the IL-6 receptor (IL-6R) induces homodimerization and recruitment of glycoprotein 130 (gp130), which leads to activation of downstream signaling. Emerging evidence suggests that high levels of IL-6 are correlated with poor prognosis in breast cancer patients. IL-6 appears to play a critical role in the growth and metastasis of breast cancer cells, renewal of breast cancer stem cells (BCSCs), and drug resistance of BCSCs, making anti-IL-6/IL-6R/gp130 therapies promising options for the treatment and prevention of breast cancers. However, preclinical and clinical studies of the applications of anti-IL-6/IL-6R/gp130 therapy in breast cancers are limited. In this review, we summarize the structures, preclinical and clinical studies, mechanisms of action of chemical and biological blockers that directly bind to IL-6, IL-6R, or gp130, and the potential clinical applications of these pharmacological agents as breast cancer therapies.

Tumor-related interleukins: old validated targets for new anti-cancer drug development

In-depth knowledge of cancer molecular and cellular mechanisms have revealed a strong regulation of cancer development and progression by the inflammation which orchestrates the tumor microenvironment. Immune cells, residents or recruited, in the inflammation milieu can have rather contrasting effects during cancer development. Accumulated clinical and experimental data support the notion that acute inflammation could exert an immunoprotective effect leading to tumor eradication. However, chronic immune response promotes tumor growth and invasion. These reactions are mediated by soluble mediators or cytokines produced by either host immune cells or tumor cells themselves. Herein, we provide an overview of the current understanding of the role of the best-validated cytokines involved in tumor progression, IL-1, IL-4 and IL-6; in addition to IL-2 cytokines family, which is known to promote tumor eradication by immune cells. Furthermore, we summarize the clinical attempts to block or bolster the effect of these tumor-related interleukins in anti-cancer therapy development.

A Novel IL6 Antibody Sensitizes Multiple Tumor Types to Chemotherapy Including Trastuzumab-Resistant Tumors

Elevated levels of the proinflammatory cytokine IL6 are associated with poor survival outcomes in many cancers. Antibodies targeting IL6 and its receptor have been developed for chronic inflammatory disease, but they have not yet been shown to clearly benefit cancer patients, possibly due to antibody potency or the settings in which they have been tested. In this study, we describe the development of a novel high-affinity anti-IL6 antibody, MEDI5117, which features an extended half-life and potent inhibitory effects on IL6 biologic activity. MEDI5117 inhibited IL6-mediated activation of STAT3, suppressing the growth of several tumor types driven by IL6 autocrine signaling. In the same models, MEDI5117 displayed superior preclinical activity relative to a previously developed anti-IL6 antibody. Consistent with roles for IL6 in promoting tumor angiogenesis, we found that MEDI5117 inhibited the growth of endothelial cells, which can produce IL6 and support tumorigenesis. Notably, in tumor xenograft assays in mice, we documented the ability of MEDI5117 to enhance the antitumor activities of chemotherapy or gefitinib in combination treatment regimens. MEDI5117 also displayed robust activity on its own against trastuzumab-resistant HER2(+) tumor cells by targeting the CD44(+)CD24(-) cancer stem cell population. Collectively, our findings extend the evidence of important pleiotropic roles of IL6 in tumorigenesis and drug resistance, and offer a preclinical proof of concept for the use of IL6 antibodies in combination regimens to heighten therapeutic responses and overcome drug resistance.

Process of hepatic metastasis from pancreatic cancer: biology with clinical significance

PURPOSE

Pancreatic cancer shows a remarkable preference for the liver to establish secondary tumors. Selective metastasis to the liver is attributed to the development of potential microenvironment for the survival of pancreatic cancer cells. This review aims to provide a full understanding of the hepatic metastatic process from circulating pancreatic cancer cells to their settlement in the liver, serving as a basic theory for efficient prediction and treatment of metastatic diseases.

METHODS

A systematic search of relevant original articles and reviews was performed on PubMed, EMBASE and Cochrane Library for the purpose of this review.

RESULTS

Three interrelated phases are delineated as the contributions of the interaction between pancreatic cancer cells and the liver to hepatic metastasis process. Chemotaxis of disseminated pancreatic cancer cells and simultaneous defensive formation of platelets or neutrophils facilitate specific metastasis toward the liver. Remodeling of extracellular matrix and stromal cells in hepatic lobules and angiogenesis induced by proangiogenic factors support the survival and growth of clinical micrometastasis colonizing the liver. The bimodal role of the immune system or prevalence of cancer cells over the immune system makes metastatic progression successfully proceed from micrometastasis to macrometastasis.

CONCLUSIONS

Pancreatic cancer is an appropriate research object of cancer metastasis representing more than a straight cascade. If any of the successive or simultaneous phases, especially tumor-induced immunosuppression, is totally disrupted, hepatic metastasis will be temporarily under control or even cancelled forever. To shrink cancers on multiple fronts and prolong survival for patients, novel oral or intravenous anti-cancer agents covering one or different phases of metastatic pancreatic cancer are expected to be integrated into innovative strategies on the premise of safety and efficacious biostability.

Siltuximab (CNTO 328): a promising option for human malignancies

Siltuximab (CNTO 328) is a promising antibody-drug conjugate targeting cytokine interleukin-6 (IL-6). It is highly binding to IL-6 and thus neutralizing IL-6 bioactivity and promoting death of tumor cell. In this review, we mainly focus on the mechanisms, clinical studies, and adverse effect of siltuximab in the treatment of human malignancies. We also provide our recommendations for siltuximab treatment in the future.

The IL-6 feed-forward loop: a driver of tumorigenesis

IL-6 signaling plays a prominent role in tumorigenesis and metastasis. In this review we discuss the recent evidence describing the tumor intrinsic and extrinsic functions of this signaling pathway. Although blockade of this pathway in pre-clinical models leads to a reduction in tumor growth and metastasis, its clinical success is less evident. Thus, identifying the features of tumors/patients that predict response to anti-IL6 therapy are needed.

Novel agents for multiple myeloma to overcome resistance in phase III clinical trials

The incorporation of novel agents such as bortezomib and lenalidomide into initial therapy for multiple myeloma has improved the response rate of induction regimens. Also, these drugs are being increasingly used in the peri-transplant setting for transplant-eligible patients, and as part of consolidation and/or maintenance after front-line treatment, including in transplant-ineligible patients. Together, these and other strategies have contributed to a prolongation of progression-free survival (PFS) and overall survival (OS) in myeloma patients, and an increasing proportion are able to sustain a remission for many years. Despite these improvements, however, the vast majority of patients continue to suffer relapses, which suggests a prominent role for either primary, innate drug resistance, or secondary, acquired drug resistance. As a result, there remains a strong need to develop new proteasome inhibitors and immunomodulatory agents, as well as new drug classes, which would be effective in the relapsed and/or refractory setting, and overcome drug resistance. This review will focus on novel drugs that have reached phase III trials, including carfilzomib and pomalidomide, which have recently garnered regulatory approvals. In addition, agents that are in phase II or III, potentially registration-enabling trials will be described as well, to provide an overview of the possible landscape in the relapsed and/or refractory arena over the next 5 years.

Targeting interleukin-6 in inflammatory autoimmune diseases and cancers

Interleukin-6 (IL-6) is a pleiotropic cytokine with significant functions in the regulation of the immune system. As a potent pro-inflammatory cytokine, IL-6 plays a pivotal role in host defense against pathogens and acute stress. However, increased or deregulated expression of IL-6 significantly contributes to the pathogenesis of various human diseases. Numerous preclinical and clinical studies have revealed the pathological roles of the IL-6 pathway in inflammation, autoimmunity, and cancer. Based on the rich body of studies on biological activities of IL-6 and its pathological roles, therapeutic strategies targeting the IL-6 pathway are in development for cancers, inflammatory and autoimmune diseases. Several anti-IL-6/IL-6 receptor monoclonal antibodies developed for targeted therapy have demonstrated promising results in both preclinical studies and clinical trials. Tocilizumab, an anti-IL-6 receptor antibody, is effective in the treatment of various autoimmune and inflammatory conditions notably rheumatoid arthritis. It is the only IL-6 pathway targeting agent approved by the regulatory agencies for clinical use. Siltuximab, an anti-IL-6 antibody, has been shown to have potential benefits treating various human cancers either as a single agent or in combination with other chemotherapy drugs. Several other anti-IL-6-based therapies are also under clinical development for various diseases. IL-6 antagonism has been shown to be a potential therapy for these disorders refractory to conventional drugs. New strategies, such as combination of IL-6 blockade with inhibition of other signaling pathways, may further improve IL-6-targeted immunotherapy of human diseases.

Impact of interleukin-6 in hematological malignancies

Almost 3 decades have passed since the discovery and cloning of IL-6, and a tremendous amount of work has contributed to the current knowledge of the biological functions of this cytokine, its receptor, and the signaling pathways that are activated. The understanding of the role of IL-6 in human disease has led to the development of novel therapeutic strategies that block the biological functions of IL-6. In clinical studies, IL-6 and IL-6 receptor antibodies have proven efficacy in rheumatoid arthritis, systemic juvenile idiopathic arthritis, and Castleman's disease, conditions that are known to be driven by IL-6. The focus of this overview is the role of IL-6 in the pathophysiology of hematological malignancies.