Immuno-Oncology: New Insights into Targets and Therapies.

The role of immunotherapy in the care of surgical oncology patients promises to expand as investigators and clinicians evaluate new targets and approaches. Currently active clinical trials evaluate new immune checkpoints, including lymphocyte activation gene 3, T cell immunoreceptor with Ig and ITIM domains, and killer Ig-like receptor 2DL1/2L3. Vaccines delivered through mRNA have demonstrated exciting results in early clinical trials and hold promise for expanded application. Investigational approaches include dendritic cell vaccines, peptide vaccines, cytokines therapies, and cellular therapies. These studies have the potential to revolutionize the management of surgical oncology patients and promote durable cures following surgical resection.

Tumor heterogeneity in VHL drives metastasis in clear cell renal cell carcinoma.

Loss of function of the von Hippel-Lindau (VHL) tumor suppressor gene is a hallmark of clear cell renal cell carcinoma (ccRCC). The importance of heterogeneity in the loss of this tumor suppressor has been under reported. To study the impact of intratumoral VHL heterogeneity observed in human ccRCC, we engineered VHL gene deletion in four RCC models, including a new primary tumor cell line derived from an aggressive metastatic case. The VHL gene-deleted (VHL-KO) cells underwent epithelial-to-mesenchymal transition (EMT) and exhibited increased motility but diminished proliferation and tumorigenicity compared to the parental VHL-expressing (VHL+) cells. Renal tumors with either VHL+ or VHL-KO cells alone exhibit minimal metastatic potential. Combined tumors displayed rampant lung metastases, highlighting a novel cooperative metastatic mechanism. The poorly proliferative VHL-KO cells stimulated the proliferation, EMT, and motility of neighboring VHL+ cells. Periostin (POSTN), a soluble protein overexpressed and secreted by VHL non-expressing (VHL-) cells, promoted metastasis by enhancing the motility of VHL-WT cells and facilitating tumor cell vascular escape. Genetic deletion or antibody blockade of POSTN dramatically suppressed lung metastases in our preclinical models. This work supports a new strategy to halt the progression of ccRCC by disrupting the critical metastatic crosstalk between heterogeneous cell populations within a tumor.

UNcommon EGFR Mutations: International Case Series on Efficacy of Osimertinib in Real-Life Practice in First-LiNe Setting (UNICORN).

INTRODUCTION: Approximately 10% of EGFR mutations (EGFRmuts) are uncommon (ucEGFRmuts). We aimed to collect real-world data about osimertinib for patients with ucEGFRmuts. METHODS: This is a multicenter, retrospective study of ucEGFRmut (exon 20 insertions excluded) metastatic NSCLC treated with osimertinib as first EGFR inhibitor. The Response Evaluation Criteria in Solid Tumors and response assessment in neuro-oncology brain metastases brain objective response rate (ORR) were evaluated by the investigators. Median progression-free survival (mPFS), median overall survival, and median duration of response (mDOR) were calculated from osimertinib initiation. Mutations found at resistance were collected. RESULTS: A total of 60 patients were included (22 centers, nine countries), with median age of 64 years, 75% females, and 83% Caucasian. The largest subgroups were G719X (30%), L861Q (20%), and de novo Thr790Met (T790M) (15%). The ORR was 61%, mPFS 9.5 months, mDOR 17.4 months, and median overall survival 24.5 months. Regarding patients with no concurrent common mutations or T790M (group A, n = 44), ORR was 60%, mPFS 8.6 months, and mDOR 11 months. For G719X, ORR was 47%, mPFS 8.8 months, and mDOR 9.1 months. For L861Q, ORR was 80%, mPFS 16 months, and mDOR 16 months. For de novo T790M, ORR was 44%, mPFS 12.7 months, and mDOR 46.2 months. Compound EGFRmut including common mutations had better outcome compared with only ucEGFRmut. For 13 patients with a response assessment in neuro-oncology brain metastases-evaluable brain metastases, brain ORR was 46%. For 14 patients, rebiopsy results were analyzed: four patients with additional EGFR mutation (C797S, D585Y, E709K), three with new TP53 mutation, one with c-Met amplification, one with PIK3CA mutation, and one with neuroendocrine transformation. CONCLUSIONS: Osimertinib was found to have an activity in ucEGFRmut with a high rate of disease control systemically and intracranially. Several resistance mechanisms were identified. This report comprises, to the best of our knowledge, the largest data set of its kind.

The Role of Chemotherapy Plus Immune Checkpoint Inhibitors in Oncogenic-Driven NSCLC: A University of California Lung Cancer Consortium Retrospective Study.

Introduction: There is a paucity of data on immune checkpoint inhibitors (ICIs) plus doublet chemotherapy (C) in patients with advanced lung cancer whose tumor harbors an actionable mutation. We sought to provide insight into the role of this combination in relation to chemotherapy alone in this patient population. Methods: We conducted a retrospective study at the five University of California National Cancer Institute-designated Comprehensive Cancer Centers. The primary end point was progression-free survival (PFS). Secondary end points included overall survival (OS) and significant adverse events. Adverse events in patients who received a tyrosine kinase inhibitor (TKI) post-ICI were also captured. Results: A total of 246 patients were identified, 170 treated with C plus ICI and 76 treated with C alone. Driver alterations included EGFR (54.9%), KRAS (32.9%), ALK (5.3%), HER2/ERBB2 (2.9%), ROS1 (1.2%), MET (1.2%), RET (0.8%), and BRAF non-V600 (0.8%). The overall PFS and OS hazard ratios were not significant at 1.12 (95% confidence interval 0.83-1.51; p = 0.472) and 0.86 (95% confidence interval: 0.60-1.24, p = 0.429), respectively. No significant differences in PFS or OS were observed in the mutational subgroups. Grade 3 or greater adverse events were lower in the C plus ICI group. The multivariate analysis for PFS and OS revealed a performance status (Eastern Cooperative Oncology Group) score of 2, and previous TKI treatment was associated with poorer outcomes with C plus ICI. Conclusions: Our study suggests that patients with oncogenic-driven NSCLC, primarily those with EGFR-driven tumors, treated with a TKI should not subsequently receive C plus ICI. Analysis from prospective clinical trials will provide additional information on the role of ICIs in this group of patients.

HER2 and HER3 as Therapeutic Targets in Head and Neck Cancer.

ABSTRACT: Work over the past several decades has identified that aberrations in the ErbB signaling pathways are key drivers of oncogenesis, and concurrent efforts to discover targetable vulnerabilities to counter this aberrant oncogenic signaling offer tremendous promise in treating a host of human cancers. These efforts have been centered primarily on EGFR (also known as HER1), leading to the discovery of the first targeted therapies approved for head and neck cancer. More recently, HER2 and HER3 signaling pathways have been identified as highly dysregulated in head and neck cancer. This review highlights the HER2 and HER3 signaling pathways and clinical efforts to target these receptors and their aberrant signaling to treat head and neck squamous cell carcinomas and other head and neck malignancies, including salivary gland carcinomas. This includes the use of small molecule inhibitors and blocking antibodies, both as single agents or as part of multimodal precision targeted and immunotherapies.

Lymphatic-preserving treatment sequencing with immune checkpoint inhibition unleashes cDC1-dependent antitumor immunity in HNSCC.

Despite the promise of immune checkpoint inhibition (ICI), therapeutic responses remain limited. This raises the possibility that standard of care treatments delivered in concert may compromise the tumor response. To address this, we employ tobacco-signature head and neck squamous cell carcinoma murine models in which we map tumor-draining lymphatics and develop models for regional lymphablation with surgery or radiation. We find that lymphablation eliminates the tumor ICI response, worsening overall survival and repolarizing the tumor- and peripheral-immune compartments. Mechanistically, within tumor-draining lymphatics, we observe an upregulation of conventional type I dendritic cells and type I interferon signaling and show that both are necessary for the ICI response and lost with lymphablation. Ultimately, we provide a mechanistic understanding of how standard oncologic therapies targeting regional lymphatics impact the tumor response to immune-oncology therapy in order to define rational, lymphatic-preserving treatment sequences that mobilize systemic antitumor immunity, achieve optimal tumor responses, control regional metastatic disease, and confer durable antitumor immunity.

An overview of alectinib hydrochloride as a treatment option for ALK positive non-small cell lung cancer.

Introduction: Alectinib is a second-generation inhibitor of anaplastic lymphoma kinase (ALK) and RET. Phase III clinical trials have established its superiority to crizotinib in the first-line ALK inhibitor-naïve setting. Studies also support its use over chemotherapy in the post-crizotinib setting. It is currently one of several FDA- and EMA-approved ALK inhibitors, and it is listed as a preferred initial therapy for treatment-naïve ALK-positive non-small cell lung cancer (NSCLC).Areas covered: Herein, the authors provide the reader with details of the chemical structure, pharmacologic properties, resistance mutations, phase I, II, and III clinical trials, and safety profile of alectinib. Furthermore, the authors provide the reader with the expert opinion and future perspectives on the drug.Expert opinion: Alectinib compares favorably to other second-generation ALK inhibitors with regards to safety, tolerability, and efficacy. Based on currently available data, it is an appropriate first-line option. Ongoing studies will better resolve the ideal sequencing of ALK inhibitors in the treatment of ALK-positive NSCLC.

A Non-integrating Lentiviral Approach Overcomes Cas9-Induced Immune Rejection to Establish an Immunocompetent Metastatic Renal Cancer Model.

The CRISPR-based technology has revolutionized genome editing in recent years. This technique allows for gene knockout and evaluation of function in cell lines in a manner that is far easier and more accessible than anything previously available. Unfortunately, the ability to extend these studies to in vivo syngeneic murine cell line implantation is limited by an immune response against cells transduced to stably express Cas9. In this study, we demonstrate that a non-integrating lentiviral vector approach can overcome this immune rejection and allow for the growth of transduced cells in an immunocompetent host. This technique enables the establishment of a von Hippel-Lindau (VHL) gene knockout RENCA cell line in BALB/c mice, generating an improved model of immunocompetent, metastatic renal cell carcinoma (RCC).

CRISPR-Mediated VHL Knockout Generates an Improved Model for Metastatic Renal Cell Carcinoma.

Metastatic renal cell carcinoma (mRCC) is nearly incurable and accounts for most of the mortality associated with RCC. Von Hippel Lindau (VHL) is a tumour suppressor that is lost in the majority of clear cell RCC (ccRCC) cases. Its role in regulating hypoxia-inducible factors-1α (HIF-1α) and -2α (HIF-2α) is well-studied. Recent work has demonstrated that VHL knock down induces an epithelial-mesenchymal transition (EMT) phenotype. In this study we showed that a CRISPR/Cas9-mediated knock out of VHL in the RENCA model leads to morphologic and molecular changes indicative of EMT, which in turn drives increased metastasis to the lungs. RENCA cells deficient in HIF-1α failed to undergo EMT changes upon VHL knockout. RNA-seq revealed several HIF-1α-regulated genes that are upregulated in our VHL knockout cells and whose overexpression signifies an aggressive form of ccRCC in the cancer genome atlas (TCGA) database. Independent validation in a new clinical dataset confirms the upregulation of these genes in ccRCC samples compared to adjacent normal tissue. Our findings indicate that loss of VHL could be driving tumour cell dissemination through stabilization of HIF-1α in RCC. A better understanding of the mechanisms involved in this phenomenon can guide the search for more effective treatments to combat mRCC.

Effect of Dietary Omega-3 Fatty Acids on Tumor-Associated Macrophages and Prostate Cancer Progression.

BACKGROUND: Preclinical and clinical studies suggest that a fish oil-based diet may play a role in delaying the progression of prostate cancer through a number of different mechanisms involving inflammatory pathways. Given the importance of tumor-associated macrophages (TAMs) in carcinogenesis, we hypothesized that a fish oil-based diet will inhibit TAM infiltration and delay the growth of prostate cancer. METHODS: Androgen sensitive mouse prostate cancer (MycCaP) allograft tumors were grown in fully immunocompetent FVB mice fed a high- fat fish oil (omega-3) or corn oil (omega-6) diet. Gene expression of markers for immune cell populations, cytokines, chemokines, and signaling pathways were determined by real-time PCR and western blot in tumor tissue. Cell proliferation and apoptosis in vitro were measured by MTS assay and flow cytometry. RESULTS: Tumor volumes were significantly smaller in mice in ω-3 versus the ω-6 group (P = 0.048). Gene expression of markers for M1 and M2 macrophages (F4/80, iNOS, ARG1), associated cytokines (IL-6, TNF alpha, IL-10), and the chemokine CCL-2 were also lower in the omega-3 group. Correlative in vitro studies were performed in M1 and M2 polarized macrophages and mirrored the in vivo findings. Dietary fish oil and in vitro omega-3 fatty acid administration reduced protein expression of transcription factors in the nuclear factor kappa B pathway leading to a significant decrease in gene expression of downstream targets (Bcl-2, BCL-XL, XIAP, survivin) in MycCap cells. CONCLUSIONS: These findings underscore the potential of fish oil in modulating the clinical course of human prostate cancer through the immune system. Further preclinical and clinical studies are warranted evaluating fish oil-based therapies for inhibiting the recruitment and function of M1 and M2 tumor infiltrating macrophages. Prostate 76:1293-1302, 2016. © 2016 Wiley Periodicals, Inc.

Macrophage Blockade Using CSF1R Inhibitors Reverses the Vascular Leakage Underlying Malignant Ascites in Late-Stage Epithelial Ovarian Cancer.

Malignant ascites is a common complication in the late stages of epithelial ovarian cancer (EOC) that greatly diminishes the quality of life of patients. Malignant ascites is a known consequence of vascular dysfunction, but current approved treatments are not effective in preventing fluid accumulation. In this study, we investigated an alternative strategy of targeting macrophage functions to reverse the vascular pathology of malignant ascites using fluid from human patients and an immunocompetent murine model (ID8) of EOC that mirrors human disease by developing progressive vascular disorganization and leakiness culminating in massive ascites. We demonstrate that the macrophage content in ascites fluid from human patients and the ID8 model directly correlates with vascular permeability. To further substantiate macrophages' role in the pathogenesis of malignant ascites, we blocked macrophage function in ID8 mice using a colony-stimulating factor 1 receptor kinase inhibitor (GW2580). Administration of GW2580 in the late stages of disease resulted in reduced infiltration of protumorigenic (M2) macrophages and dramatically decreased ascites volume. Moreover, the disorganized peritoneal vasculature became normalized and sera from GW2580-treated ascites protected against endothelial permeability. Therefore, our findings suggest that macrophage-targeted treatment may be a promising strategy toward a safe and effective means to control malignant ascites of EOC.

CSF1 receptor targeting in prostate cancer reverses macrophage-mediated resistance to androgen blockade therapy.

Growing evidence suggests that tumor-associated macrophages (TAM) promote cancer progression and therapeutic resistance by enhancing angiogenesis, matrix-remodeling, and immunosuppression. In this study, prostate cancer under androgen blockade therapy (ABT) was investigated, demonstrating that TAMs contribute to prostate cancer disease recurrence through paracrine signaling processes. ABT induced the tumor cells to express macrophage colony-stimulating factor 1 (M-CSF1 or CSF1) and other cytokines that recruit and modulate macrophages, causing a significant increase in TAM infiltration. Inhibitors of CSF1 signaling through its receptor, CSF1R, were tested in combination with ABT, demonstrating that blockade of TAM influx in this setting disrupts tumor promotion and sustains a more durable therapeutic response compared with ABT alone.

MicroRNAs miR-146a/b negatively modulate the senescence-associated inflammatory mediators IL-6 and IL-8.

Senescence is a cellular program that irreversibly arrests the proliferation of damaged cells and induces the secretion of the inflammatory mediators IL- 6 and IL-8 which are part of a larger senescence associated secretory phenotype (SASP). We screened quiescent and senescent human fibroblasts for differentially expressed microRNAS (miRNAs) and found that miRNAs 146a and 146b (miR-146a/b) were significantly elevated during senescence. We suggest that delayed miR-146a/b induction might be a compensatory response to restrain inflammation. Indeed, ectopic expression of miR-146a/b in primary human fibroblasts suppressed IL-6 and IL-8 secretion and downregulated IRAK1, a crucial component of the IL-1 receptor signal transduction pathway. Cells undergoing senescence without induction of a robust SASP did not express miR-146a/b. Further, IL-1alpha neutralizing antibodies abolished both miR-146a/b expression and IL-6 secretion. Our findings expand the biological contexts in which miRNA-146a/b modulates inflammatory responses. They suggest that IL-1 receptor signaling initiates both miR-146a/b upregulation and cytokine secretion, and that miR-146a/b is expressed in response to rising inflammatory cytokine levels as part of a negative feedback loop that restrains excessive SASP activity.

The splicing regulatory element, UGCAUG, is phylogenetically and spatially conserved in introns that flank tissue-specific alternative exons.

Previous studies have identified UGCAUG as an intron splicing enhancer that is frequently located adjacent to tissue-specific alternative exons in the human genome. Here, we show that UGCAUG is phylogenetically and spatially conserved in introns that flank brain-enriched alternative exons from fish to man. Analysis of sequence from the mouse, rat, dog, chicken and pufferfish genomes revealed a strongly statistically significant association of UGCAUG with the proximal intron region downstream of brain-enriched alternative exons. The number, position and sequence context of intronic UGCAUG elements were highly conserved among mammals and in chicken, but more divergent in fish. Control datasets, including constitutive exons and non-tissue-specific alternative exons, exhibited a much lower incidence of closely linked UGCAUG elements. We propose that the high sequence specificity of the UGCAUG element, and its unique association with tissue-specific alternative exons, mark it as a critical component of splicing switch mechanism(s) designed to activate a limited repertoire of splicing events in cell type-specific patterns. We further speculate that highly conserved UGCAUG-binding protein(s) related to the recently described Fox-1 splicing factor play a critical role in mediating this specificity.