Oncogenic ras-induced expression of cytokines: a new target of anti-cancer therapeutics

Tumor biomarkers for diagnosis, prognosis and targeted therapy

Tumor biomarkers, the substances which are produced by tumors or the body's responses to tumors during tumorigenesis and progression, have been demonstrated to possess critical and encouraging value in screening and early diagnosis, prognosis prediction, recurrence detection, and therapeutic efficacy monitoring of cancers. Over the past decades, continuous progress has been made in exploring and discovering novel, sensitive, specific, and accurate tumor biomarkers, which has significantly promoted personalized medicine and improved the outcomes of cancer patients, especially advances in molecular biology technologies developed for the detection of tumor biomarkers. Herein, we summarize the discovery and development of tumor biomarkers, including the history of tumor biomarkers, the conventional and innovative technologies used for biomarker discovery and detection, the classification of tumor biomarkers based on tissue origins, and the application of tumor biomarkers in clinical cancer management. In particular, we highlight the recent advancements in biomarker-based anticancer-targeted therapies which are emerging as breakthroughs and promising cancer therapeutic strategies. We also discuss limitations and challenges that need to be addressed and provide insights and perspectives to turn challenges into opportunities in this field. Collectively, the discovery and application of multiple tumor biomarkers emphasized in this review may provide guidance on improved precision medicine, broaden horizons in future research directions, and expedite the clinical classification of cancer patients according to their molecular biomarkers rather than organs of origin.

Clinical Potential of YY1-Hypoxia Axis for Vascular Normalization and to Improve Immunotherapy

Abnormal vasculature in solid tumors causes poor blood perfusion, hypoxia, low pH, and immune evasion. It also shapes the tumor microenvironment and affects response to immunotherapy. The combination of antiangiogenic therapy and immunotherapy has emerged as a promising approach to normalize vasculature and unlock the full potential of immunotherapy. However, the unpredictable and redundant mechanisms of vascularization and immune suppression triggered by tumor-specific hypoxic microenvironments indicate that such combination therapies need to be further evaluated to improve patient outcomes. Here, we provide an overview of the interplay between tumor angiogenesis and immune modulation and review the function and mechanism of the YY1-HIF axis that regulates the vascular and immune tumor microenvironment. Furthermore, we discuss the potential of targeting YY1 and other strategies, such as nanocarrier delivery systems and engineered immune cells (CAR-T), to normalize tumor vascularization and re-establish an immune-permissive microenvironment to enhance the efficacy of cancer therapy.

New insights into RAS in head and neck cancer

RAS genes are known to be dysregulated in cancer for several decades, and substantial effort has been dedicated to develop agents that reduce RAS expression or block RAS activation. The recent introduction of RAS inhibitors for cancer patients highlights the importance of comprehending RAS alterations in head and neck cancer (HNC). In this regard, we examine the published findings on RAS alterations and pathway activations in HNC, and summarize their role in HNC initiation, progression, and metastasis. Specifically, we focus on the intrinsic role of mutated-RAS on tumor cell signaling and its extrinsic role in determining tumor-microenvironment (TME) heterogeneity, including promoting angiogenesis and enhancing immune escape. Lastly, we summarize the intrinsic and extrinsic role of RAS alterations on therapy resistance to outline the potential of targeting RAS using a single agent or in combination with other therapeutic agents for HNC patients with RAS-activated tumors.

Ras family signaling pathway in immunopathogenesis of inflammatory rheumatic diseases

The Ras (rat sarcoma virus) is a GTP-binding protein that is considered one of the important members of the Ras-GTPase superfamily. The Ras involves several pathways in the cell that include proliferation, migration, survival, differentiation, and fibrosis. Abnormalities in the expression level and activation of the Ras family signaling pathway and its downstream kinases such as Raf/MEK/ERK1-2 contribute to the pathogenic mechanisms of rheumatic diseases including immune system dysregulation, inflammation, and fibrosis in systemic sclerosis (SSc); destruction and inflammation of synovial tissue in rheumatoid arthritis (RA); and autoantibody production and immune complexes formation in systemic lupus erythematosus (SLE); and enhance osteoblast differentiation and ossification during skeletal formation in ankylosing spondylitis (AS). In this review, the basic biology, signaling of Ras, and abnormalities in this pathway in rheumatic diseases including SSc, RA, AS, and SLE will be discussed.

A Comparative Review of Pregnancy and Cancer and Their Association with Endoplasmic Reticulum Aminopeptidase 1 and 2

The fundamental basis of pregnancy and cancer is to determine the fate of the survival or the death of humanity. However, the development of fetuses and tumors share many similarities and differences, making them two sides of the same coin. This review presents an overview of the similarities and differences between pregnancy and cancer. In addition, we will also discuss the critical roles that Endoplasmic Reticulum Aminopeptidase (ERAP) 1 and 2 may play in the immune system, cell migration, and angiogenesis, all of which are essential for fetal and tumor development. Even though the comprehensive understanding of ERAP2 lags that of ERAP1 due to the lack of an animal model, recent studies have shown that both enzymes are associated with an increased risk of several diseases, including pregnancy disorder pre-eclampsia (PE), recurrent miscarriages, and cancer. The exact mechanisms in both pregnancy and cancer need to be elucidated. Therefore, a deeper understanding of ERAP's role in diseases can make it a potential therapeutic target for pregnancy complications and cancer and offer greater insight into its impact on the immune system.

Thirty-five years since the discovery of chemotactic cytokines, interleukin-8 and MCAF: A historical overview

Inflammation is a host defense response to various invading stimuli, but an excessive and persistent inflammatory response can cause tissue injury, which can lead to irreversible organ damage and dysfunction. Excessive inflammatory responses are believed to link to most human diseases. A specific type of leukocyte infiltration into invaded tissues is required for inflammation. Historically, the underlying molecular mechanisms of this process during inflammation were an enigma, compromising research in the fields of inflammation, immunology, and pathology. However, the pioneering discovery of chemotactic cytokines (chemokines), monocyte-derived neutrophil chemotactic factor (MDNCF; interleukin [IL]-8, CXCL8) and monocyte chemotactic and activating factor (MCAF; monocyte chemotactic factor 1 [MCP-1], CCL2) in the late 1980s finally enabled us to address this issue. In this review, we provide a historical overview of chemokine research over the last 35 years.

RAS oncogenic activity predicts response to chemotherapy and outcome in lung adenocarcinoma

Activating mutations in KRAS occur in 32% of lung adenocarcinomas (LUAD). Despite leading to aggressive disease and resistance to therapy in preclinical studies, the KRAS mutation does not predict patient outcome or response to treatment, presumably due to additional events modulating RAS pathways. To obtain a broader measure of RAS pathway activation, we developed RAS84, a transcriptional signature optimised to capture RAS oncogenic activity in LUAD. We report evidence of RAS pathway oncogenic activation in 84% of LUAD, including 65% KRAS wild-type tumours, falling into four groups characterised by coincident alteration of STK11/LKB1, TP53 or CDKN2A, suggesting that the classifications developed when considering only KRAS mutant tumours have significance in a broader cohort of patients. Critically, high RAS activity patient groups show adverse clinical outcome and reduced response to chemotherapy. Patient stratification using oncogenic RAS transcriptional activity instead of genetic alterations could ultimately assist in clinical decision-making.

Interleukin-8: An evolving chemokine

Early in the 1980s several laboratories mistakenly reported that partially purified interleukin-1 (IL-1) was chemotactic for neutrophils. However, further investigations by us, revealed that our purified IL-1 did not have neutrophil chemotactic activity and this activity in the LPS-stimulated human monocyte conditioned media could clearly be separated from IL-1 activity on HPLC gel filtration. This motivated Teizo Yoshimura and Kouji Matsushima to purify the monocyte-derived neutrophil chemotactic factor (MDNCF), present in LPS conditioned media and molecularly clone the cDNA for MDNCF. They found that MDNCF protein (later renamed IL-8, and finally termed CXCL8) is first translated as a precursor form consisting of 99 amino acid residues and the signal peptide is then removed, leading to the secretion and processing of biologically active IL-8 of 72 amino acid form (residues 28-99). There are four cysteine residues forming two disulfide linkage and 14 basic amino acid residues which result in a very basic property for the binding of IL-8 to heparan sulfate-proteoglycan. The IL-8 gene consists of 4 exons and 3 introns. IL-8 is produced by various types of cells in inflammation. The 5'-flanking region of IL-8 gene contains several nuclear factor binding sites, and NF-κB in combination with AP-1 or C/EBP synergistically activates IL-8 gene in response to IL-1 and TNFα. Two receptors exist for IL-8, CXCR1 and CXCR2 in humans, which belong to γ subfamily of GTP binding protein (G-protein) coupled rhodopsin-like 7 transmembrane domain receptors. Rodents express CXCR2 and do not produce IL-8, but produce numerous homologues instead. Once IL-8 binds to the receptor, β and γ subunits of G-protein are released from Gα (Gαi2 in neutrophils) and activate PI3Kγ, PLCβ2/β3, PLA2 and PLD. Gαi2 inhibits adenyl cyclase to decrease cAMP levels. Small GTPases Ras/Rac/Rho/cdc42/Rap1, PKC and AKT (PKB) exist down-stream of β and γ subunits and regulate cell adhesion, actin polymerization, membrane protrusion, and eventually cell migration. PLCβ activation generates IP3 and induces Ca⁺⁺ mobilization, DAG generation to activate protein kinase C to lead granule exocytosis and respiratory burst. MDNCF was renamed interleukin 8 (IL-8) at the International Symposium on Novel Neutrophil Chemotactic Activating Polypeptides, London, UK in 1989. The discovery of IL-8 prompted us to also purify and molecularly clone the cDNA of MCAF/MCP-1 responsible for monocyte chemotaxis, and other groups to identify a large family of chemotactic cytokines capable of attracting other types of leukocytes. In 1992, most of the investigators contributing to the discovery of this new family of chemotactic cytokines gathered in Baden, Austria and agreed to name this family "chemokines" and subsequently established the CXCL/CCL and CXCR/CCR nomenclature. The discovery of chemokines resulted in solving the long-time enigma concerning the mechanism of cell type specific leukocyte infiltration into inflamed tissues and provided a molecular basis for immune and hematopoietic cell migration and interactions under physiological as well as pathological conditions. To our surprise based on its recently identified multifunctional activities, IL-8 has evolved from a neutrophil chemoattractant to a promising therapeutic target for a wide range of inflammatory and neoplastic diseases. IL-8 was initially characterized as a chemoattractant of neutrophils engaged in acute inflammation and then discovered to also be chemotactic for endothelial cells with a major role in angiogenesis. These two activities of IL-8 foster its stimulatory effect on tumor growth. This is abetted by recent additional discoveries showing that IL-8 has stimulatory effects on stem cells and can therefore directly promote the growth of receptor expressing cancer stem cells. IL-8 by interacting with bone marrow stem/progenitor cells has also the capacity to mobilize and release hematopoietic cells into the peripheral circulation. This includes the mobilization of neutrophilic myeloid-derived suppressor cells (N-MDSC) to infiltrate into tumors and thus further promotes the immune escape of tumors. Finally, the capacity of IL-8 to induce trans-differentiation of epithelial cancer cells into mesenchymal phenotype (EMT) increases the malignancy of tumors by promoting their metastatic spread and resistance to chemotherapeutics and cytotoxic immune cells. These observations have stimulated considerable current efforts to develop receptor antagonists for IL-8 and humanized anti-IL-8 antibody for the therapy of cancer, particularly in combination with immune checkpoint inhibitors, such as anti-PD-1/PD-L1 antibodies.

Ras-p53 genomic cooperativity as a model to investigate mechanisms of innate immune regulation in gastrointestinal cancers

Despite increasingly thorough mechanistic understanding of the dominant genetic drivers of gastrointestinal (GI) tumorigenesis (e.g., Ras/Raf, TP53, etc.), only a small proportion of these molecular alterations are therapeutically actionable. In an attempt to address this therapeutic impasse, our group has proposed an innovative extreme outlier model to identify novel cooperative molecular vulnerabilities in high-risk GI cancers which dictate prognosis, correlate with distinct patterns of metastasis, and define therapeutic sensitivity or resistance. Our model also proposes comprehensive investigation of their downstream transcriptomic, immunomic, metabolic, or upstream epigenomic cellular consequences to reveal novel therapeutic targets in previously “undruggable” tumors with high-risk genomic features. Leveraging this methodology, our and others’ data reveal that the genomic cooperativity between Ras and p53 alterations is not only prognostically relevant in GI malignancy, but may also represent the incipient molecular events that initiate and sustain innate immunoregulatory signaling networks within the GI tumor microenvironment, driving T-cell exclusion and therapeutic resistance in these cancers. As such, deciphering the unique transcriptional programs encoded by Ras-p53 cooperativity that promote innate immune trafficking and chronic inflammatory tumor-stromal-immune crosstalk may uncover immunologic vulnerabilities that could be exploited to develop novel therapeutic strategies for these difficult-to-treat malignancies.

Pan-RAS inhibitors: Hitting multiple RAS isozymes with one stone

Mutations in the three RAS oncogenes are present in approximately 30% of all human cancers that drive tumor growth and metastasis by aberrant activation of RAS-mediated signaling. Despite the well-established role of RAS in tumorigenesis, past efforts to develop small molecule inhibitors have failed for various reasons leading many to consider RAS as "undruggable." Advances over the past decade with KRAS(G12C) mutation-specific inhibitors have culminated in the first FDA-approved RAS drug, sotorasib. However, the patient population that stands to benefit from KRAS(G12C) inhibitors is inherently limited to those patients harboring KRAS(G12C) mutations. Additionally, both intrinsic and acquired mechanisms of resistance have been reported that indicate allele-specificity may afford disadvantages. For example, the compensatory activation of uninhibited wild-type (WT) NRAS and HRAS isozymes can rescue cancer cells harboring KRAS(G12C) mutations from allele-specific inhibition or the occurrence of other mutations in KRAS. It is therefore prudent to consider alternative drug discovery strategies that may overcome these potential limitations. One such approach is pan-RAS inhibition, whereby all RAS isozymes co-expressed in the tumor cell population are targeted by a single inhibitor to block constitutively activated RAS regardless of the underlying mutation. This chapter provides a review of past and ongoing strategies to develop pan-RAS inhibitors in detail and seeks to outline the trajectory of this promising strategy of RAS inhibition.

The Importance of Being PI3K in the RAS Signaling Network

Ras proteins are essential mediators of a multitude of cellular processes, and its deregulation is frequently associated with cancer appearance, progression, and metastasis. Ras-driven cancers are usually aggressive and difficult to treat. Although the recent Food and Drug Administration (FDA) approval of the first Ras G12C inhibitor is an important milestone, only a small percentage of patients will benefit from it. A better understanding of the context in which Ras operates in different tumor types and the outcomes mediated by each effector pathway may help to identify additional strategies and targets to treat Ras-driven tumors. Evidence emerging in recent years suggests that both oncogenic Ras signaling in tumor cells and non-oncogenic Ras signaling in stromal cells play an essential role in cancer. PI3K is one of the main Ras effectors, regulating important cellular processes such as cell viability or resistance to therapy or angiogenesis upon oncogenic Ras activation. In this review, we will summarize recent advances in the understanding of Ras-dependent activation of PI3K both in physiological conditions and cancer, with a focus on how this signaling pathway contributes to the formation of a tumor stroma that promotes tumor cell proliferation, migration, and spread.

The KRASG12C Inhibitor MRTX849 Reconditions the Tumor Immune Microenvironment and Sensitizes Tumors to Checkpoint Inhibitor Therapy

KRAS^G12C inhibitors, including MRTX849, are promising treatment options for KRAS-mutant non-small cell lung cancer (NSCLC). PD-1 inhibitors are approved in NSCLC; however, strategies to enhance checkpoint inhibitor therapy (CIT) are needed. KRAS^G12C mutations are smoking-associated transversion mutations associated with high tumor mutation burden, PD-L1 positivity, and an immunosuppressive tumor microenvironment. To evaluate the potential of MRTX849 to augment CIT, its impact on immune signaling and response to CIT was evaluated. In human tumor xenograft models, MRTX849 increased MHC class I protein expression and decreased RNA and/or plasma protein levels of immunosuppressive factors. In a Kras^G12C -mutant CT26 syngeneic mouse model, MRTX849 decreased intratumoral myeloid-derived suppressor cells and increased M1-polarized macrophages, dendritic cells, CD4⁺, and CD8⁺ T cells. Similar results were observed in lung Kras^G12C -mutant syngeneic and a genetically engineered mouse (GEM) model. In the CT26 Kras^G12C model, MRTX849 demonstrated marked tumor regression when tumors were established in immune-competent BALB/c mice; however, the effect was diminished when tumors were grown in T-cell-deficient nu/nu mice. Tumors progressed following anti-PD-1 or MRTX849 single-agent treatment in immune-competent mice; however, combination treatment demonstrated durable, complete responses (CRs). Tumors did not reestablish in the same mice that exhibited durable CRs when rechallenged with tumor cell inoculum, demonstrating these mice developed adaptive antitumor immunity. In a GEM model, treatment with MRTX849 plus anti-PD-1 led to increased progression-free survival compared with either single agent alone. These data demonstrate KRAS inhibition reverses an immunosuppressive tumor microenvironment and sensitizes tumors to CIT through multiple mechanisms.

TPL2 enforces RAS-induced inflammatory signaling and is activated by point mutations

NF-κB transcription factors, driven by the IRAK/IKK cascade, confer treatment resistance in pancreatic ductal adenocarcinoma (PDAC), a cancer characterized by near-universal KRAS mutation. Through reverse-phase protein array and RNA sequencing we discovered that IRAK4 also contributes substantially to MAPK activation in KRAS-mutant PDAC. IRAK4 ablation completely blocked RAS-induced transformation of human and murine cells. Mechanistically, expression of mutant KRAS stimulated an inflammatory, autocrine IL-1β signaling loop that activated IRAK4 and the MAPK pathway. Downstream of IRAK4, we uncovered TPL2 (also known as MAP3K8 or COT) as the essential kinase that propels both MAPK and NF-κB cascades. Inhibition of TPL2 blocked both MAPK and NF-κB signaling, and suppressed KRAS-mutant cell growth. To counter chemotherapy-induced genotoxic stress, PDAC cells upregulated TLR9, which activated prosurvival IRAK4/TPL2 signaling. Accordingly, a TPL2 inhibitor synergized with chemotherapy to curb PDAC growth in vivo. Finally, from TCGA we characterized 2 MAP3K8 point mutations that hyperactivate MAPK and NF-κB cascades by impeding TPL2 protein degradation. Cancer cell lines naturally harboring these MAP3K8 mutations are strikingly sensitive to TPL2 inhibition, underscoring the need to identify these potentially targetable mutations in patients. Overall, our study establishes TPL2 as a promising therapeutic target in RAS- and MAP3K8-mutant cancers and strongly prompts development of TPL2 inhibitors for preclinical and clinical studies.

Inflammatory Responses during Tumour Initiation: From Zebrafish Transgenic Models of Cancer to Evidence from Mouse and Man

The zebrafish is now an important model organism for cancer biology studies and provides unique and complementary opportunities in comparison to the mammalian equivalent. The translucency of zebrafish has allowed in vivo live imaging studies of tumour initiation and progression at the cellular level, providing novel insights into our understanding of cancer. Here we summarise the available transgenic zebrafish tumour models and discuss what we have gleaned from them with respect to cancer inflammation. In particular, we focus on the host inflammatory response towards transformed cells during the pre-neoplastic stage of tumour development. We discuss features of tumour-associated macrophages and neutrophils in mammalian models and present evidence that supports the idea that these inflammatory cells promote early stage tumour development and progression. Direct live imaging of tumour initiation in zebrafish models has shown that the intrinsic inflammation induced by pre-neoplastic cells is tumour promoting. Signals mediating leukocyte recruitment to pre-neoplastic cells in zebrafish correspond to the signals that mediate leukocyte recruitment in mammalian tumours. The activation state of macrophages and neutrophils recruited to pre-neoplastic cells in zebrafish appears to be heterogenous, as seen in mammalian models, which provides an opportunity to study the plasticity of innate immune cells during tumour initiation. Although several potential mechanisms are described that might mediate the trophic function of innate immune cells during tumour initiation in zebrafish, there are several unknowns that are yet to be resolved. Rapid advancement of genetic tools and imaging technologies for zebrafish will facilitate research into the mechanisms that modulate leukocyte function during tumour initiation and identify targets for cancer prevention.

Single-cell analysis of a mutant library generated using CRISPR-guided deaminase in human melanoma cells

CRISPR-based screening methods using single-cell RNA sequencing (scRNA-seq) technology enable comprehensive profiling of gene perturbations from knock-out mutations. However, evaluating substitution mutations using scRNA-seq is currently limited. We combined CRISPR RNA-guided deaminase and scRNA-seq technology to develop a platform for introducing mutations in multiple genes and assessing the mutation-associated signatures. Using this platform, we generated a library consisting of 420 sgRNAs, performed sgRNA tracking analysis, and assessed the effect size of the response to vemurafenib in the human melanoma cell line, which has been well-studied via knockout-based drop-out screens. However, a substitution mutation library screen has not been applied and transcriptional information for mechanisms of action was not assessed. Our platform permits discrimination of several candidate mutations that function differently from other mutations by integrating sgRNA candidates and gene expression readout. We anticipate that our platform will enable high-throughput analyses of the mechanisms related to a variety of biological events.

A role for IL-34 in osteolytic disease of multiple myeloma

Multiple myeloma (MM) is a hematological malignancy that grows in multiple sites of the axial skeleton and causes debilitating osteolytic disease. Interleukin-34 (IL-34) is a newly discovered cytokine that acts as a ligand of colony-stimulating factor-1 (CSF-1) receptor and can replace CSF-1 for osteoclast differentiation. In this study, we identify IL-34 as an osteoclastogenic cytokine that accelerates osteolytic disease in MM. IL-34 was found to be expressed in the murine MM cell line MOPC315.BM, and the expression of IL-34 was enhanced by stimulation with proinflammatory cytokines or by bone marrow (BM) stromal cells. MM-cell-derived IL-34 promoted osteoclast formation from mouse BM cells in vitro. Targeting Il34 by specific small interfering RNA impaired osteoclast formation in vitro and attenuated osteolytic disease in vivo. In BM aspirates from MM patients, the expression levels of IL-34 in CD138⁺ populations vary among patients from high to weak to absent. MM cell-derived IL-34 promoted osteoclast formation from human CD14⁺ monocytes, which was reduced by a neutralizing antibody against IL-34. Taken together, this study describes for the first time the expression of IL-34 in MM cells, indicating that it may enhance osteolysis and suggesting IL-34 as a potential therapeutic target to control pathological osteoclastogenesis in MM patients.

Cancer-Specific Loss of p53 Leads to a Modulation of Myeloid and T Cell Responses

Loss of p53 function contributes to the development of many cancers. While cell-autonomous consequences of p53 mutation have been studied extensively, the role of p53 in regulating the anti-tumor immune response is still poorly understood. Here, we show that loss of p53 in cancer cells modulates the tumor-immune landscape to circumvent immune destruction. Deletion of p53 promotes the recruitment and instruction of suppressive myeloid CD11b+ cells, in part through increased expression of CXCR3/CCR2-associated chemokines and macrophage colony-stimulating factor (M-CSF), and attenuates the CD4+ T helper 1 (Th1) and CD8+ T cell responses in vivo. p53-null tumors also show an accumulation of suppressive regulatory T (Treg) cells. Finally, we show that two key drivers of tumorigenesis, activation of KRAS and deletion of p53, cooperate to promote immune tolerance.

Major Complications Independently Increase Long-Term Mortality After Pancreatoduodenectomy for Cancer

BACKGROUND

Postoperative major morbidity has been associated with worse survival gastrointestinal tumors. This association remains controversial in pancreatic cancer (PC). We analyzed whether major complications after surgical resection affect long-term survival.

METHODS

Records of all PC patients resected from 2007 to 2015 were reviewed. Major morbidity was defined as any grade-3 or higher 30-day complications, per the Clavien-Dindo Classification. Patients who died within 90 days after surgery were excluded from survival analysis.

RESULTS

Of 616 patients, 81.7% underwent pancreatoduodenectomy (PD) and 18.3% distal pancreatectomy (DP). Major complications occurred in 19.1% after PD and 15.9% after DP. In patients who survived > 90 days, the likelihood of receiving adjuvant treatment was 43.9% if major complications had occurred, vs. 68.5% if not (p < 0.001), and those who received it started the treatment median 10 days later compared with uncomplicated patients (median 60 days (50-72) vs. 50 days (41-61), p = 0.001). By univariate analysis, in addition to the conventional pathology-related prognostic determinants and the receipt of adjuvant treatment, major complications worsened long-term survival after PD (median OS 26 months vs. 15, p = 0.008). A difference was also seen after DP, but it did not reach statistical significance, likely related to the small sample size (median OS 33 months vs. 18, p = 0.189). At multivariate analysis for PD, major postoperative complications remained independently associated with worse survival [HR 1.37, 95%CI (1.01-1.86)].

CONCLUSIONS

Major surgical complications after pancreaticoduodenectomy are associated with worse long-term survival in pancreatic cancer. This effect is independent of the receipt of adjuvant treatment.

Suppression of interferon gene expression overcomes resistance to MEK inhibition in KRAS-mutant colorectal cancer

Despite showing clinical activity in BRAF-mutant melanoma, the MEK inhibitor (MEKi) trametinib has failed to show clinical benefit in KRAS-mutant colorectal cancer. To identify mechanisms of resistance to MEKi, we employed a pharmacogenomic analysis of MEKi-sensitive versus MEKi-resistant colorectal cancer cell lines. Strikingly, interferon- and inflammatory-related gene sets were enriched in cell lines exhibiting intrinsic and acquired resistance to MEK inhibition. The bromodomain inhibitor JQ1 suppressed interferon-stimulated gene (ISG) expression and in combination with MEK inhibitors displayed synergistic effects and induced apoptosis in MEKi-resistant colorectal cancer cell lines. ISG expression was confirmed in patient-derived organoid models, which displayed resistance to trametinib and were resensitized by JQ1 co-treatment. In in vivo models of colorectal cancer, combination treatment significantly suppressed tumor growth. Our findings provide a novel explanation for the limited response to MEK inhibitors in KRAS-mutant colorectal cancer, known for its inflammatory nature. Moreover, the high expression of ISGs was associated with significantly reduced survival of colorectal cancer patients. Excitingly, we have identified novel therapeutic opportunities to overcome intrinsic and acquired resistance to MEK inhibition in colorectal cancer.

Epithelial-Stromal Interactions in Pancreatic Cancer

Pancreatic cancer is characterized by an extensive fibroinflammatory reaction that includes immune cells, fibroblasts, extracellular matrix, vascular and lymphatic vessels, and nerves. Overwhelming evidence indicates that the pancreatic cancer microenvironment regulates cancer initiation, progression, and maintenance. Pancreatic cancer treatment has progressed little over the past several decades, and the prognosis remains one of the worst for any cancer. The contribution of the microenvironment to carcinogenesis is a key area of research, offering new potential targets for treating the disease. Here, we explore the composition of the pancreatic cancer stroma, discuss the network of interactions between different components, and describe recent attempts to target the stroma therapeutically. We also discuss current areas of active research related to the tumor microenvironment.

KRAS mutation and epithelial-macrophage interplay in pancreatic neoplastic transformation

Pancreatic ductal adenocarcinoma (PDA) is characterized by epithelial mutations in KRAS and prominent tumor-associated inflammation, including macrophage infiltration. But knowledge of early interactions between neoplastic epithelium and macrophages in PDA carcinogenesis is limited. Using a pancreatic organoid model, we found that the expression of mutant KRAS in organoids increased (i) ductal to acinar gene expression ratios, (ii) epithelial cells proliferation and (iii) colony formation capacity in vitro, and endowed pancreatic cells with the ability to generate neoplastic tumors in vivo. KRAS mutations induced a protumorigenic phenotype in macrophages. Altered macrophages decreased epithelial pigment epithelial derived factor (PEDF) expression and induced a cancerous phenotype. We validated our findings using annotated patient samples from The Cancer Genome Atlas (TCGA) and in our human PDA specimens. Epithelium-macrophage cross-talk occurs early in pancreatic carcinogenesis where KRAS directly induces cancer-related phenotypes in epithelium, and also promotes a protumorigenic phenotype in macrophages, in turn augmenting neoplastic growth.

RAS-mediated oncogenic signaling pathways in human malignancies

Abnormally activated RAS proteins are the main oncogenic driver that governs the functioning of major signaling pathways involved in the initiation and development of human malignancies. Mutations in RAS genes and or its regulators, most frequent in human cancers, are the main force for incessant RAS activation and associated pathological conditions including cancer. In general, RAS is the main upstream regulator of the highly conserved signaling mechanisms associated with a plethora of important cellular activities vital for normal homeostasis. Mutated or the oncogenic RAS aberrantly activates a web of interconnected signaling pathways including RAF-MEK (mitogen-activated protein kinase kinase)-ERK (extracellular signal-regulated kinase), phosphoinositide-3 kinase (PI3K)/AKT (protein kinase B), protein kinase C (PKC) and ral guanine nucleotide dissociation stimulator (RALGDS), etc., leading to uncontrolled transcriptional expression and reprogramming in the functioning of a range of nuclear and cytosolic effectors critically associated with the hallmarks of carcinogenesis. This review highlights the recent literature on how oncogenic RAS negatively use its signaling web in deregulating the expression and functioning of various effector molecules in the pathogenesis of human malignancies.

PEDF inhibits pancreatic tumorigenesis by attenuating the fibro-inflammatory reaction

Pancreatic cancer is characterized by a pronounced fibro-inflammatory reaction that has been shown to contribute to cancer progression. Previous reports have demonstrated that pigment epithelium-derived factor (PEDF) has potent tumor suppressive effects in pancreatic cancer, though little is known about the mechanisms by which PEDF limits pancreatic tumorigenesis. We therefore employed human specimens, as well as mouse and in vitro models, to explore the effects of PEDF upon the pancreatic microenvironment. We found that PEDF expression is decreased in human pancreatic cancer samples compared to non-malignant tissue. Furthermore, PEDF-deficient patients displayed increased intratumoral inflammation/fibrosis. In mice, genetic ablation of PEDF increased cerulein-induced inflammation and fibrosis, and similarly enhanced these events in the background of oncogenic KRAS. In vitro, recombinant PEDF neutralized macrophage migration as well as inhibited macrophage-induced proliferation of tumor cells. Additionally, recombinant PEDF suppressed the synthesis of pro-inflammatory/pro-fibrotic cytokines both in vivo and in vitro, and reduced collagen I deposition and TGFβ synthesis by pancreatic stellate cells, consistent with reduced fibrosis. Combined, our results demonstrate that PEDF limits pancreatic cancer progression by attenuating the fibro-inflammatory reaction, and makes restoration of PEDF signaling a potential therapeutic approach to study in pancreatic cancer.

Myc Cooperates with Ras by Programming Inflammation and Immune Suppression

The two oncogenes KRas and Myc cooperate to drive tumorigenesis, but the mechanism underlying this remains unclear. In a mouse lung model of KRasG12D-driven adenomas, we find that co-activation of Myc drives the immediate transition to highly proliferative and invasive adenocarcinomas marked by highly inflammatory, angiogenic, and immune-suppressed stroma. We identify epithelial-derived signaling molecules CCL9 and IL-23 as the principal instructing signals for stromal reprogramming. CCL9 mediates recruitment of macrophages, angiogenesis, and PD-L1-dependent expulsion of T and B cells. IL-23 orchestrates exclusion of adaptive T and B cells and innate immune NK cells. Co-blockade of both CCL9 and IL-23 abrogates Myc-induced tumor progression. Subsequent deactivation of Myc in established adenocarcinomas triggers immediate reversal of all stromal changes and tumor regression, which are independent of CD4+CD8+ T cells but substantially dependent on returning NK cells. We show that Myc extensively programs an immune suppressive stroma that is obligatory for tumor progression.

Tumor Acidosis and Hypoxia Differently Modulate the Inflammatory Program: Measurements In Vitro and In Vivo

Inflammatory mediators produced by the tumor cells are of importance for immune response but also for malignant progression. The aim of the study was to analyze the expression of monocyte chemoattractant protein-1, interleukin-6 (IL-6), tumor necrosis factor-α, inducible isoform of nitric oxide synthase (iNOS), cyclooxygenase-2, and osteopontin in vitro in two different tumor cell lines under hypoxia (pO₂ ≈ 1.5 mmHg) and/or acidosis (pH = 6.6) for up to 24 hours since hypoxia and acidosis are common characteristics of solid tumors. Additionally, the same tumor cell lines implanted in vivo were made hypoxic and acidotic artificially for 24 hours, after which the cytokine expression was measured. Finally, the activation of ERK1/2 and p38 by acidosis/hypoxia and their impact on cytokine expression were studied. The results indicate that acidosis and hypoxia have fundamentally different (often opposing) effects on cytokine expression. In addition, these effects were tumor cell line specific. When combining hypoxia and acidosis, the overall changes reflect an additive effect of both conditions alone, indicating that hypoxia and acidosis act by independent mechanisms. The in vivo changes corresponded well with the results obtained in the isolated tumor cells. Only iNOS expression was downregulated in vivo but increased in cell culture. For IL-6 expression, the acidosis-induced changes were dependent on ERK1/2 activation. In conclusion, it was demonstrated that the environmental pO₂ and pH strongly affect the expression of inflammatory mediators in tumor cells. In vivo, most of the inflammatory mediators were downregulated, which could limit the activation of immune cells and by this foster the immune escape of tumors.

New tricks for human farnesyltransferase inhibitor: cancer and beyond

Human protein farnesyltransferase (FTase) catalyzes the addition of a C15-farnesyl lipid group to the cysteine residue located in the COOH-terminal tetrapeptide motif of a variety of important substrate proteins, including well-known Ras protein superfamily. The farnesylation of Ras protein is required both for its normal physiological function, and for the transforming capacity of its oncogenic mutants. Over the last several decades, FTase inhibitors (FTIs) were developed to disrupt the farnesylation of oncogenic Ras as anti-cancer agents, and some of them have entered cancer clinical investigation. On the other hand, some substrates of FTase were demonstrated to be related with other human diseases, including Hutchinson-Gilford progeria syndrome, chronic hepatitis D, and cardiovascular diseases. In this review, we summarize the roles of FTase in malignant transformation, proliferation, apoptosis, angiogenesis, and metastasis of tumor cells, and the recently anticancer clinical research advances of FTIs. The therapeutic prospect of FTIs on several other human diseases is also discussed.

Covalent Guanosine Mimetic Inhibitors of G12C KRAS

Ras proteins are members of a large family of GTPase enzymes that are commonly mutated in cancer where they act as dominant oncogenes. We previously developed an irreversible guanosine-derived inhibitor, SML-8-73-1, of mutant G12C RAS that forms a covalent bond with cysteine 12. Here we report exploration of the structure-activity relationships (SAR) of hydrolytically stable analogues of SML-8-73-1 as covalent G12C KRAS inhibitors. We report the discovery of difluoromethylene bisphosphonate analogues such as compound 11, which, despite exhibiting reduced efficiency as covalent G12C KRAS inhibitors, remove the liability of the hydrolytic instability of the diphosphate moiety present in SML-8-73-1 and provide the foundation for development of prodrugs to facilitate cellular uptake. The SAR and crystallographic results reaffirm the exquisite molecular recognition that exists in the diphosphate region of RAS for guanosine nucleotides which must be considered in the design of nucleotide-competitive inhibitors.

CXCR2 signaling regulates KRAS(G¹²D)-induced autocrine growth of pancreatic cancer

Pharmacological inhibition of RAS, the master regulator of pancreatic ductal adenocarcinoma (PDAC), continues to be a challenge. Mutations in various isoforms of RAS gene, including KRAS are known to upregulate CXC chemokines; however, their precise role in KRAS-driven pancreatic cancer remains unclear. In this report, we reveal a previously unidentified tumor cell-autonomous role of KRAS^(G12D)-induced CXCR2 signaling in mediating growth of neoplastic PDAC cells. Progressively increasing expression of mCXCR2 and its ligands was detected in the malignant ductal cells of Pdx1-cre;LSL-Kras^(G12D) mice. Knocking-down CXCR2 in KRAS^(G12D)-bearing human pancreatic duct-derived cells demonstrated a significant decrease in the in vitro and in vivo tumor cell proliferation. Furthermore, CXCR2 antagonists showed selective growth inhibition of KRAS^(G12D)-bearing cells in vitro. Intriguingly, both genetic and pharmacological inhibition of CXCR2 signaling in KRAS^(G12D)-bearing pancreatic ductal cells reduced the levels of KRAS protein, strongly implying the presence of a KRAS-CXCR2 feed-forward loop. Together, these data demonstrate the role of CXCR2 signaling in KRAS^(G12D)-induced growth transformation and progression in PDAC.

Hall of Fame among Pro-inflammatory Cytokines: Interleukin-6 Gene and Its Transcriptional Regulation Mechanisms

Pro-inflammatory cytokines that are generated by immune system cells and mediate many kinds of immune responses are kinds of endogenous polypeptides. They are also the effectors of the autoimmune system. It is generally accepted that interleukin (IL)-4, IL-6, IL-9, IL-17, and tumor necrosis factor-α are pro-inflammatory cytokines; however, IL-6 becomes a protagonist among them since it predominately induces pro-inflammatory signaling and regulates massive cellular processes. It has been ascertained that IL-6 is associated with a large number of diseases with inflammatory background, such as anemia of chronic diseases, angiogenesis acute-phase response, bone metabolism, cartilage metabolism, and multiple cancers. Despite great progress in the relative field, the targeted regulation of IL-6 response for therapeutic benefits remains incompletely to be understood. Therefore, it is conceivable that understanding mechanisms of IL-6 from the perspective of gene regulation can better facilitate to determine the pathogenesis of the disease, providing more solid scientific basis for clinical treatment translation. In this review, we summarize the candidate genes that have been implicated in clinical target therapy from the perspective of gene transcription regulation.

Targeting pathways downstream of KRAS in lung adenocarcinoma

Oncogenic KRAS activation is responsible for the most common genetic subtype of lung cancer. Although many of the major downstream signaling pathways that KRAS engages have been defined, these discoveries have yet to translate into effective targeted therapy. Much of the current focus has been directed at inhibiting the activation of RAF/MAPK and PI3K/AKT signaling, but clinical trials combining multiple different agents that target these pathways have failed to show significant activity. In this article, we will discuss the evidence for RAF and PI3K as key downstream RAS effectors, as well as the RAL guanine exchange factor, which is equally essential for transformation. Furthermore, we will delineate alternative pathways, including cytokine activation and autophagy, which are co-opted by oncogenic RAS signaling and also represent attractive targets for therapy. Finally, we will present strategies for combining inhibitors of these downstream KRAS signaling pathways in a rational fashion, as multitargeted therapy will be required to achieve a cure.

The prognostic significance of CXCL1 hypersecretion by human colorectal cancer epithelia and myofibroblasts

Background

Clinical therapy for metastatic colorectal cancer (CRC) remains limited, especially when the tumor harbors a KRAS mutation. This study aimed to identify prognostic biomarkers in CRC that are accessible for therapeutic inhibition.

Methods

Conditioned media from human CRC epithelial cells and myofibroblasts were screened by cytokine arrays for tumorigenic factors. The protein and mRNA expressions of these factors were determined by immunohistochemistry and gene microarrays in human CRC tissues. Prognostic biomarkers were determined by correlation of mRNA expression to overall survival in stage IV CRC patients. Inhibition of CXCL1 was performed with specific neutralizing antibody and lentiviral shRNAs. Malignant growth was assessed by soft agar growth assays and xenograft tumor growth in immunocompromised mice.

Results

CXCL1 was highly secreted by KRAS mutant human CRC cells and myofibroblasts in a complementary adaptive response to serum deprivation. Elevated CXCL1 level promoted anchorage-independent growth of murine fibroblasts and human CRC cells. Inhibition of CXCL1 by neutralizing antibody and specific shRNAs decreased CRC tumor growth. Highly elevated CXCL1 expression significantly correlated with decreased overall survival in stage IV CRC patients (hazard ratio 0.28; 95% CI 0.11–0.72).

Conclusions

High CXCL1 expression is a poor prognostic biomarker in metastatic CRC. CXCL1 inhibition suppressed tumorigenic growth of KRAS mutant CRC cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-015-0555-4) contains supplementary material, which is available to authorized users.

RB mutation and RAS overexpression induce resistance to NK cell-mediated cytotoxicity in glioma cells

Several theories aim to explain the malignant transformation of cells, including the mutation of tumor suppressors and proto-oncogenes. Deletion of Rb (a tumor suppressor), overexpression of mutated Ras (a proto-oncogene), or both, are sufficient for in vitro gliomagenesis, and these genetic traits are associated with their proliferative capacity. An emerging hallmark of cancer is the ability of tumor cells to evade the immune system. Whether specific mutations are related with this, remains to be analyzed. To address this issue, three transformed glioma cell lines were obtained (Rb^−/−, Ras^V12, and Rb^−/−/Ras^V12) by in vitro retroviral transformation of astrocytes, as previously reported. In addition, Ras^V12 and Rb^−/−/Ras^V12 transformed cells were injected into SCID mice and after tumor growth two stable glioma cell lines were derived. All these cells were characterized in terms of Rb and Ras gene expression, morphology, proliferative capacity, expression of MHC I, Rae1δ, and Rae1αβγδε, mult1, H60a, H60b, H60c, as ligands for NK cell receptors, and their susceptibility to NK cell-mediated cytotoxicity. Our results show that transformation of astrocytes (Rb loss, Ras overexpression, or both) induced phenotypical and functional changes associated with resistance to NK cell-mediated cytotoxicity. Moreover, the transfer of cell lines of transformed astrocytes into SCID mice increased resistance to NK cell-mediated cytotoxicity, thus suggesting that specific changes in a tumor suppressor (Rb) and a proto-oncogene (Ras) are enough to confer resistance to NK cell-mediated cytotoxicity in glioma cells and therefore provide some insight into the ability of tumor cells to evade immune responses.

Comparative analysis of KRAS codon 12, 13, 18, 61, and 117 mutations using human MCF10A isogenic cell lines

KRAS mutations occur in one third of human cancers and cluster in several hotspots, with codons 12 and 13 being most commonly affected. It has been suggested that the position and type of amino acid exchange influence the transforming capacity of mutant KRAS proteins. We used MCF10A human mammary epithelial cells to establish isogenic cell lines that express different cancer-associated KRAS mutations (G12C, G12D, G12V, G13C, G13D, A18D, Q61H, K117N) at physiological or elevated levels, and investigated the biochemical and functional consequences of the different variants. The overall effects of low-expressing mutants were moderate compared to overexpressed variants, but allowed delineation of biological functions that were related to specific alleles rather than KRAS expression level. None of the mutations induced morphological changes, migratory abilities, or increased phosphorylation of ERK, PDK1, and AKT. KRAS-G12D, G12V, G13D, and K117N mediated EGF-independent proliferation, whereas anchorage-independent growth was primarily induced by K117N and Q61H. Both codon 13 mutations were associated with increased EGFR expression. Finally, global gene expression analysis of MCF10A-G13D versus MCF10A-G12D revealed distinct transcriptional changes. Together, we describe a useful resource for investigating the function of multiple KRAS mutations and provide insights into the differential effects of these variants in MCF10A cells.

Antitumor efficacy of the anti-interleukin-6 (IL-6) antibody siltuximab in mouse xenograft models of lung cancer

INTRODUCTION

Interleukin-6 (IL-6) can activate downstream signaling pathways in lung cancer cells, such as the STAT3 pathway, and is reported to be produced by tumor cells with activating EGFR mutations. We examined IL-6/STAT3 in lung cancer tumor tissues and the effects of siltuximab, a neutralizing antibody to human IL-6, in mouse models of lung cancer.

METHODS

IL-6 and STAT3 activation levels were compared with tumor histology and presence of KRAS mutations in snap-frozen, non-small-cell lung cancer tumors. The effects of siltuximab alone or in combination with erlotinib were examined in mouse xenograft models constructed using three cell line xenograft models and one primary explant mouse model. We examined the influence of cancer-associated fibroblasts (CAFs) on tumor growth and siltuximab effects.

RESULTS

IL-6 levels were higher in tumors of squamous cell versus adenocarcinoma histology and were not associated with presence of KRAS mutations. Tyrosine phosphorylation status of STAT3 did not correlate with tumor IL-6 levels. Serine phosphorylation of STAT3 was correlated with KRAS mutation status. Both tumor and stromal cells contributed to total IL-6 within tumors. Siltuximab had minimal effect as a single agent in xenografts with tumor cells alone; however, in models coadministered with CAFs, siltuximab had more potent effects on tumor inhibition. We observed no effects of combined erlotinib and siltuximab.

CONCLUSIONS

IL-6 is elevated in subsets of human NSCLCs, especially with squamous cell histology. Tumors supported by stromal production of IL-6 seem to be the most vulnerable to tumor growth inhibition by siltuximab.

The association between expressions of Ras and CD68 in the angiogenesis of breast cancers

Objective

Angiogenesis is a critical step of breast cancer metastasis. Oncogenic Ras promotes the remodeling of cancer microenviroment. Tumor-associated macrophages (TAMs) are a prominent inflammatory cell population emerging in the microenviroment and facilitating the angiogenesis and metastasis. In the present study, we tried to investigate the relationship between the expression of Ras and infiltration of TAM, both of which could further promote angiogenesis.

Methods

Expressions of Ras, CD68 and CD34 were assessed by immunohistochemistry. The infiltration of macrophages was evaluated by counting the number of CD68⁺ cells. Vessel endothelial cells were defined as CD34⁺ cells. Angiogenesis vascularity was defined by microvessel density (MVD) assay through counting the number of vessels per field counted in the area of highest vascular density. The Kaplan–Meier survival analysis was used to estimate the overall survival (OS). Macrophages were derived from monocytes in the presence of macrophage colony-stimulating-factor (MCSF). Breast cancer cells were treated with macrophage-conditioned medium (MCM) and tested the expressions of K-, H- and N-Ras by using realtime-PCR.

Results

Ras positive status was correlated with ER, PR and Her-2 positivity, larger tumour size and lymph node metastasis, as well as higher TNM stages. A higher number of CD68⁺ cells was correlated with larger tumour size, higher TNM stages and Her-2 positivity. Both Ras positivity and infiltration of CD68⁺ macrophages correlated with poor OS. The number of CD68⁺ cells was positively correlated with the expression of Ras. Treatment with MCM did not up-regulate but repressed the expression of Ras. Both up-regulation of Ras and infiltration of TAMs correlated with increased MVD.

Conclusion

Expression of Ras and infiltration of TAM were positively correlated, and both participated in angiogenesis. Elevated Ras could be responsible for the infiltration of TAM.

Abrogation of protein phosphatase 6 promotes skin carcinogenesis induced by DMBA

Somatic mutations in the gene encoding the catalytic subunit of protein phosphatase 6 (Ppp6c) have been identified in malignant melanoma and are thought to function as a driver in B-raf- or N-ras-driven tumorigenesis. To assess the role of Ppp6c in carcinogenesis, we generated skin keratinocyte-specific Ppp6c conditional knockout mice and performed two-stage skin carcinogenesis analysis. Ppp6c deficiency induced papilloma formation with 7,12-dimethylbenz (a) anthracene (DMBA) only, and development of those papillomas was significantly accelerated compared with that seen following DMBA/TPA (12-O-tetradecanoylphorbol 13-acetate) treatment of wild-type mice. NF-κB activation either by tumor necrosis factor (TNF)-α or interleukin (IL)-1β was enhanced in Ppp6c-deficient keratinocytes. Overall, we conclude that Ppp6c deficiency predisposes mice to skin carcinogenesis initiated by DMBA. This is the first report showing that such deficiency promotes tumor formation in mice.

Live imaging and gene expression analysis in zebrafish identifies a link between neutrophils and epithelial to mesenchymal transition

Chronic inflammation is associated with epithelial to mesenchymal transition (EMT) and cancer progression however the relationship between inflammation and EMT remains unclear. Here, we have exploited zebrafish to visualize and quantify the earliest events during epithelial cell transformation induced by oncogenic HRas^V12. Live imaging revealed that expression of HRas^V12 in the epidermis results in EMT and chronic neutrophil and macrophage infiltration. We have developed an in vivo system to probe and quantify gene expression changes specifically in transformed cells from chimeric zebrafish expressing oncogenic HRas^V12 using translating ribosomal affinity purification (TRAP). We found that the expression of genes associated with EMT, including slug, vimentin and mmp9, are enriched in HRas^V12 transformed epithelial cells and that this enrichment requires the presence of neutrophils. An early signal induced by HRas^V12 in epithelial cells is the expression of il-8 (cxcl8) and we found that the chemokine receptor, Cxcr2, mediates neutrophil but not macrophage recruitment to the transformed cells. Surprisingly, we also found a cell autonomous role for Cxcr2 signaling in transformed cells for both neutrophil recruitment and EMT related gene expression associated with Ras transformation. Taken together, these findings implicate both autocrine and paracrine signaling through Cxcr2 in the regulation of inflammation and gene expression in transformed epithelial cells.

Targeting cytokine networks in KRAS-driven tumorigenesis

KRAS is one of the most commonly mutated oncogenes in human tumors, and is typically associated with aggressive disease. Despite intensive study and years of effort, KRAS has remained refractory to targeted inhibition. Given the challenge of inhibiting KRAS directly, current approaches to KRAS targeted therapy have involved the disruption of downstream signaling pathways. However, combinations of drugs that target RAF/MEK and PI3K/AKT signaling have failed to live up to expectations in the clinic. Here we summarize the evidence that the cytokine signaling circuitry of KRAS-driven tumors represents an equally tractable drug target. Indeed, the incorporation of novel therapeutics that disrupts these cytokine signaling networks may hold the key to overcoming this seemingly impenetrable treatment barrier.

Nras in melanoma: targeting the undruggable target

RAS belongs to the guanosine 5'-triphosphate (GTP)-binding proteins' family, and oncogenic mutations in codons 12, 13, or 61 of RAS family occur in approximately one third of all human cancers with N-RAS mutations found in about 15-20% of melanomas. The importance of RAS signaling as a potential target in cancer is emphasized not only by the prevalence of RAS mutations, but also by the high number of RAS activators and effectors identified in mammalian cells that places the RAS proteins at the crossroads of several, important signaling networks. Ras proteins are crucial crossroads of signaling pathways that link the activation of cell surface receptors with a wide variety of cellular processes leading to the control of proliferation, apoptosis and differentiation. Furthermore, oncogenic ras proteins interfere with metabolism of tumor cells, microenvironment's remodeling, evasion of the immune response, and finally contributes to the metastatic process. After 40 years of basic, translational and clinical research, much is now known about the molecular mechanisms by which these monomeric guanosine triphosphatase-binding proteins promote cellular malignancy, and it is clear that they regulate signaling pathways involved in the control of cell proliferation, survival, and invasiveness. In this review we summarize the biological role of RAS in cancer by focusing our attention on the biological rational and strategies to target RAS in melanoma.

The Multifaceted Roles Neutrophils Play in the Tumor Microenvironment

Neutrophils are myeloid cells that constitute 50-70 % of all white blood cells in the human circulation. Traditionally, neutrophils are viewed as the first line of defense against infections and as a major component of the inflammatory process. In addition, accumulating evidence suggest that neutrophils may also play a key role in multiple aspects of cancer biology. The possible involvement of neutrophils in cancer prevention and promotion was already suggested more than half a century ago, however, despite being the major component of the immune system, their contribution has often been overshadowed by other immune components such as lymphocytes and macrophages. Neutrophils seem to have conflicting functions in cancer and can be classified into anti-tumor (N1) and pro-tumor (N2) sub-populations. The aim of this review is to discuss the varying nature of neutrophil function in the cancer microenvironment with a specific emphasis on the mechanisms that regulate neutrophil mobilization, recruitment and activation.

Pancreatic cancer, inflammation, and microbiome

Pancreatic cancer is one of the most lethal cancers worldwide. No effective screening methods exist, and available treatment modalities do not effectively treat the disease. Inflammatory conditions such as pancreatitis represent a well-known risk factor for pancreatic cancer development. Yet only in the past 2 decades has pancreatic cancer been recognized as an inflammation-driven cancer, and the precise mechanisms underlying the pathogenic role of inflammation are beginning to be explored in detail. A substantial amount of preclinical and clinical evidence suggests that bacteria are likely to influence this process by activating immune receptors and perpetuating cancer-associated inflammation. The recent explosion of investigations of the human microbiome have highlighted how perturbations of commensal bacterial populations can promote inflammation and promote disease processes, including carcinogenesis. The elucidation of the interplay between inflammation and microbiome in the context of pancreatic carcinogenesis will provide novel targets for intervention to prevent and treat pancreatic cancer more efficiently. Further studies toward this direction are urgently needed.

Carboxyl-ester lipase maturity-onset diabetes of the young is associated with development of pancreatic cysts and upregulated MAPK signaling in secretin-stimulated duodenal fluid

Carboxyl-ester lipase (CEL) maturity-onset diabetes of the young (MODY) is a monogenic form of diabetes and pancreatic exocrine dysfunction due to mutations in the CEL gene encoding CEL. The pathogenic mechanism for diabetes development is unknown. Since CEL is expressed mainly in pancreatic acinar cells, we asked whether we could find structural pancreatic changes in CEL-MODY subjects during the course of diabetes development. Furthermore, we hypothesized that the diseased pancreas releases proteins that are detectable in pancreatic fluid and potentially reflect activation or inactivation of disease-specific pathways. We therefore investigated nondiabetic and diabetic CEL-mutation carriers by pancreatic imaging studies and secretin-stimulated duodenal juice sampling. The secretin-stimulated duodenal juice was studied using cytokine assays, mass spectrometry (MS) proteomics, and multiplexed MS-based measurement of kinase activities. We identified multiple pancreatic cysts in all eight diabetic mutation carriers but not in any of the four nondiabetic mutation carriers or the six healthy controls. Furthermore, we identified upregulated mitogen-activated protein kinase (MAPK) target proteins and MAPK-driven cytokines and increased MAPK activity in the secretin-stimulated duodenal juice. These findings show that subjects with CEL-MODY develop multiple pancreatic cysts by the time they develop diabetes and that upregulated MAPK signaling in the pancreatic secretome may reflect the pathophysiological development of pancreatic cysts and diabetes.

The molecular basis for the pharmacokinetics and pharmacodynamics of curcumin and its metabolites in relation to cancer

This review addresses the oncopharmacological properties of curcumin at the molecular level. First, the interactions between curcumin and its molecular targets are addressed on the basis of curcumin's distinct chemical properties, which include H-bond donating and accepting capacity of the β-dicarbonyl moiety and the phenylic hydroxyl groups, H-bond accepting capacity of the methoxy ethers, multivalent metal and nonmetal cation binding properties, high partition coefficient, rotamerization around multiple C-C bonds, and the ability to act as a Michael acceptor. Next, the in vitro chemical stability of curcumin is elaborated in the context of its susceptibility to photochemical and chemical modification and degradation (e.g., alkaline hydrolysis). Specific modification and degradatory pathways are provided, which mainly entail radical-based intermediates, and the in vitro catabolites are identified. The implications of curcumin's (photo)chemical instability are addressed in light of pharmaceutical curcumin preparations, the use of curcumin analogues, and implementation of nanoparticulate drug delivery systems. Furthermore, the pharmacokinetics of curcumin and its most important degradation products are detailed in light of curcumin's poor bioavailability. Particular emphasis is placed on xenobiotic phase I and II metabolism as well as excretion of curcumin in the intestines (first pass), the liver (second pass), and other organs in addition to the pharmacokinetics of curcumin metabolites and their systemic clearance. Lastly, a summary is provided of the clinical pharmacodynamics of curcumin followed by a detailed account of curcumin's direct molecular targets, whereby the phenotypical/biological changes induced in cancer cells upon completion of the curcumin-triggered signaling cascade(s) are addressed in the framework of the hallmarks of cancer. The direct molecular targets include the ErbB family of receptors, protein kinase C, enzymes involved in prostaglandin synthesis, vitamin D receptor, and DNA.

Prognostic and predictive blood-based biomarkers in patients with advanced pancreatic cancer: results from CALGB80303 (Alliance)

PURPOSE

CALGB80303 was a phase III trial of 602 patients with locally advanced or metastatic pancreatic cancer comparing gemcitabine/bevacizumab versus gemcitabine/placebo. The study found no benefit in any outcome from the addition of bevacizumab to gemcitabine. Blood samples were collected and multiple angiogenic factors were evaluated and then correlated with clinical outcome in general (prognostic markers) and with benefit specifically from bevacizumab treatment (predictive markers).

EXPERIMENTAL DESIGN

Plasma samples were analyzed via a novel multiplex ELISA platform for 31 factors related to tumor growth, angiogenesis, and inflammation. Baseline values for these factors were correlated with overall survival (OS) using univariate Cox proportional hazard regression models and multivariable Cox regression models with leave-one-out cross validation. Predictive markers were identified using a treatment by marker interaction term in the Cox model.

RESULTS

Baseline plasma was available from 328 patients. Univariate prognostic markers for OS were identified including: Ang2, CRP, ICAM-1, IGFBP-1, TSP-2 (all P < 0.001). These prognostic factors were found to be highly significant, even after adjustment for known clinical factors. Additional modeling approaches yielded prognostic signatures from multivariable Cox regression. The gemcitabine/bevacizumab signature consisted of IGFBP-1, interleukin-6, PDGF-AA, PDGF-BB, TSP-2; whereas the gemcitabine/placebo signature consisted of CRP, IGFBP-1, PAI-1, PDGF-AA, P-selectin (both P < 0.0001). Finally, three potential predictive markers of bevacizumab efficacy were identified: VEGF-D (P < 0.01), SDF1 (P < 0.05), and Ang2 (P < 0.05).

CONCLUSION

This study identified strong prognostic markers for pancreatic cancer patients. Predictive marker analysis indicated that plasma levels of VEGF-D, Ang2, and SDF1 significantly predicted for benefit or lack of benefit from bevacizumab in this population.

Oncogenes and angiogenesis: a way to personalize anti-angiogenic therapy?

The acquisition of oncogenic mutations and promotion of angiogenesis are key hallmarks of cancer. These features are often thought of as separate events in tumor progression and the two fields of research have frequently been considered as independent. However, as we highlight in this review, activated oncogenes and deregulated angiogenesis are tightly associated, as mutations in cancer cells can lead to perturbation of the pro- and anti-angiogenic balance thereby causing aberrant angiogenesis. We propose that normalization of the vascular network by targeting oncogenes in the tumor cells might lead to more efficient and sustained therapeutic effects compared to therapies targeting tumor vessels. We discuss how pharmacological inhibition of oncogenes in tumor cells restores a functional vasculature by bystander anti-angiogenic effect. As genetic alterations are tumor-specific, targeted therapy, which potentially blocks the angiogenic program activated by individual oncogenes may lead to personalized anti-angiogenic therapy.

Rationale and Means to Target Pro-Inflammatory Interleukin-8 (CXCL8) Signaling in Cancer

It is well established that chronic inflammation underpins the development of a number of human cancers, with pro-inflammatory signaling within the tumor microenvironment contributing to tumor progression and metastasis. CXCL8 is an ELR⁺ pro-inflammatory CXC-chemokine which mediates its effects via signaling through two G protein-coupled receptors, CXCR1 and CXCR2. Elevated CXCL8-CXCR1/2 signaling within the tumor microenvironment of numerous cancers is known to enhance tumor progression via activation of signaling pathways promoting proliferation, angiogenesis, migration, invasion and cell survival. This review provides an overview of established roles of CXCL8-CXCR1/2 signaling in cancer and subsequently, discusses the possible strategies of targeting CXCL8-CXCR1/2 signaling in cancer, covering indirect strategies (e.g., anti-inflammatories, NFκB inhibitors) and direct CXCL8 or CXCR1/2 inhibition (e.g., neutralizing antibodies, small molecule receptor antagonists, pepducin inhibitors and siRNA strategies). Reports of pre-clinical cancer studies and clinical trials using CXCL8-CXCR1/2-targeting strategies for the treatment of inflammatory diseases will be discussed. The future translational opportunities for use of such agents in oncology will be discussed, with emphasis on exploitation in stratified populations.