BTK inhibition potentiates anti-PD-L1 treatment in murine melanoma: potential role for MDSC modulation in immunotherapy.

Myeloid-derived suppressor cells (MDSC) have been linked to loss of immune effector cell function through a variety of mechanisms such as the generation of reactive oxygen and nitrogen species and the production of inhibitory cytokines. Our group has shown that signaling through Bruton's tyrosine kinase (BTK) is important for MDSC function. Ibrutinib is an orally administered targeted agent that inhibits BTK activation and is currently used for the treatment of B cell malignancies. Using a syngeneic murine model of melanoma, the effect of BTK inhibition with ibrutinib on the therapeutic response to systemic PD-L1 blockade was studied. BTK was expressed by murine MDSC and their activation was inhibited by ibrutinib. Ibrutinib was not directly cytotoxic to cancer cells in vitro, but it inhibited BTK activation in MDSC and reduced expression of inducible nitric oxide synthase (NOS2) and production of nitric oxide. Ibrutinib treatments decreased the levels of circulating MDSC in vivo and increased the therapeutic efficacy of anti-PD-L1 antibody treatment. Gene expression profiling showed that ibrutinib decreased Cybb (NOX2) signaling, and increased IL-17 signaling (upregulating downstream targets Mmp9, Ptgs2, and S100a8). These results suggest that further exploration of MDSC inhibition could enhance the immunotherapy of advanced melanoma.PrécisInhibition of Bruton's tyrosine kinase, a key enzyme in myeloid cellular function, improves therapeutic response to an anti-PD-L1 antibody in an otherwise fairly resistant murine melanoma model.

Expression of microRNAs and their target genes in melanomas originating from gynecologic sites.

Melanomas from gynecologic sites (MOGS) are rare and have poor survival. MicroRNAs (miRs) regulate gene expression and are dysregulated in cancer. We hypothesized that MOGS would display unique miR and mRNA expression profiles. The miR and mRNA expression profile in RNA from formalin fixed, paraffin embedded vaginal melanomas (relative to vaginal mucosa) and vulvar melanomas (relative to cutaneous melanoma) were measured with the Nanostring Human miRNA assay and Tumor Signaling mRNA assay. Differential patterns of expression were identified for 21 miRs in vaginal and 47 miRs in vulvar melanoma (fold change >2, p<0.01). In vaginal melanoma, miR-145-5p (tumor suppressor targeting TLR4, NRAS) was downregulated and miR-106a-5p, miR-17-5p, miR-20b-5p (members of miR-17-92 cluster) were upregulated. In vulvar melanoma, known tumor suppressors miR-200b-3p and miR-200a-3p were downregulated, and miR-20a-5p and miR-19b-3p, from the miR-17-92 cluster, were upregulated. Pathway analysis showed an enrichment of "proteoglycans in cancer". Among differentially expressed mRNAs, topoisomerase IIα (TOP2A) was upregulated in both MOGS. Gene targets of dysregulated miRs were identified using publicly available databases and Pearson correlations. In vaginal melanoma, suppressor of cytokine signaling 3 (SOCS3) was downregulated, was a validated target of miR-19b-3p and miR-20a-5p and trended toward a significant inverse Pearson correlation with miR-19b-3p (p = 0.093). In vulvar melanoma, cyclin dependent kinase inhibitor 1A (CDKN1A) was downregulated, was the validated target of 22 upregulated miRs, and had a significant inverse Pearson correlation with miR-503-5p, miR-130a-3p, and miR-20a-5p (0.005 < p < 0.026). These findings support microRNAs as mediators of gene expression in MOGS.

Expression Patterns of microRNAs and Associated Target Genes in Ulcerated Primary Cutaneous Melanoma.

Ulcerated cutaneous melanoma carries a poor prognosis, and the underlying biology driving its aggressive behavior is largely unexplored. MicroRNAs (miRs) are small, noncoding RNAs that inhibit the expression of specific genes and exhibit dysregulated expression patterns in cancer. We hypothesized that a unique miR profile exists in ulcerated relative to nonulcerated melanoma and that miR expression inversely correlates with target genes of biologic importance. Expression of miRs and mRNAs was assessed in ulcerated and nonulcerated cutaneous melanomas using the NanoString Human miRNA and Tumor Signaling 360 mRNA assays and validated in an independent cohort. Pathway enrichment and functional annotations for differentially expressed miRs and mRNAs were determined using publicly available databases. Pearson correlations were employed to predict potential miR‒mRNA binding pairs. Ulcerated melanoma tissue showed at least 1.5-fold change in relative expression of 24 miRs, including miR-206, miR-1-3p, and miR-4286 (>2.25-fold decrease, P < 0.048) and miR-146a-5p, miR-196b-5p, and miR-363-3p (>2.5-fold increase, P < 0.014). Ulcerated melanomas also had 21 differentially expressed mRNAs relative to nonulcerated tumors (P < 0.01), among which two had an inverse correlation in expression with regulatory miRs (SOCS3 and miR-218-5p and IL7R and miR-376c-5p). This miR expression profile adds to the molecular characterization of the poorly understood histopathologic phenotype of ulcerated melanoma.

Ulcerated Cutaneous Melanoma: A Review of the Clinical, Histologic, and Molecular Features Associated with a Clinically Aggressive Histologic Phenotype.

The presence of ulceration in melanoma is associated with poor clinical outcomes and is the third most powerful predictor of survival in the AJCC Melanoma Staging System after tumor thickness and mitotic activity. The aggressive biological behavior associated with ulceration has been hypothesized to be the result of an intrinsic biological attribute that favors dissemination and presents locally with the loss of epidermal integrity. Among the features of ulcerated melanoma, many show promise as potential prognostic tools, markers of differential immunogenicity and indicators of oncogenic drivers of invasion and metastasis. The incidence of ulcerated melanoma is greater in males, increases with age and with systemic inflammatory risk factors (diabetes, smoking, low vitamin D, elevated body mass index). Patients with ulcerated primary tumors seem to exclusively benefit from adjuvant interferon (IFN) therapy, which is likely the consequence of an altered tumor microenvironment. When ulceration is present, there is a higher density of macrophages and dendritic cells and enhanced expression of pro-inflammatory cytokines, such as IL-6. There is also an increased expression of proteins involved in tumor antigen presentation in ulcerated melanomas. Histologically, vascular density, vasculogenic mimicry and angiotropism are all significantly correlated with ulceration in melanoma. The presence of ulceration is associated with reduced protein expression of E-cadherin and PTEN and elevated levels of N-cadherin and the matrix metalloproteinases. Differential microRNA expression also holds promise as a potential prognostic biomarker of malignancy and disease spread within the setting of ulceration. However, the molecular and cellular differences associated with the ulcerated state are complex and further study will aid in determining how these differences can be harnessed to improve care for patients with melanoma.

Effect of Immune Checkpoint Blockade on Myeloid-Derived Suppressor Cell Populations in Patients With Melanoma.

Introduction: Myeloid-derived suppressor cells (MDSC) are a subset of immature myeloid cells that inhibit anti-tumor immunity and contribute to immune therapy resistance. MDSC populations were measured in melanoma patients receiving immune checkpoint inhibitors (ICI). Methods: Patients with melanoma (n=128) provided blood samples at baseline (BL), and before cycles 2 and 3 (BC2, BC3). Peripheral blood mononuclear cells (PBMC) were analyzed for MDSC (CD33+/CD11b+/HLA- DRlo/-) and MDSC subsets, monocytic (CD14+, M-MDSC), granulocytic (CD15+, PMN-MDSC), and early (CD14-/CD15-, E-MDSC) via flow cytometry. Statistical analysis employed unpaired and paired t-tests across and within patient cohorts. Results: Levels of MDSC as a percentage of PBMC increased during ICI (BL: 9.2 ± 1.0% to BC3: 23.6 ± 1.9%, p<0.0001), and patients who developed progressive disease (PD) had higher baseline MDSC. In patients who had a complete or partial response (CR, PR), total MDSC levels rose dramatically and plateaued (BL: 6.4 ± 1.4%, BC2: 26.2 ± 4.2%, BC3: 27.5 ± 4.4%; p<0.0001), whereas MDSC rose less sharply in PD patients (BL: 11.7 ± 2.1%, BC2: 18.3 ± 3.1%, BC3: 19.0 ± 3.2%; p=0.1952). Subset analysis showed that within the expanding MDSC population, PMN-MDSC and E-MDSC levels decreased, while the proportion of M-MDSC remained constant during ICI. In PD patients, the proportion of PMN-MDSC (as a percentage of total MDSC) decreased (BL: 25.1 ± 4.7%, BC2: 16.1 ± 5.2%, BC3: 8.6 ± 1.8%; p=0.0105), whereas a heretofore under-characterized CD14+/CD15+ double positive MDSC subpopulation increased significantly (BL: 8.7 ± 1.4% to BC3: 26.9 ± 4.9%; p=0.0425). Conclusions: MDSC levels initially increased significantly in responders. PMN-MDSC decreased and CD14+CD15+ MDSC increased significantly in PD patients. Changes in MDSC levels may have prognostic value in ICI.

Loss of miR-1469 expression mediates melanoma cell migration and invasion.

Tumor ulceration is considered one of the most prognostically significant findings in primary cutaneous melanoma, associated with decreased disease-free and overall survival. However, the unique features associated with ulcerated melanoma that contribute to a poor prognosis in affected patients remain poorly defined. microRNAs are small, non-coding RNAs that function to inhibit expression of specific gene targets, therefore altering the functions of cells in which they are expressed. miR-1469 is a novel miR with significantly decreased expression in ulcerated melanoma tissue relative to non-ulcerated tumors. We hypothesized that loss of miR-1469 expression in melanoma contributes to altered tumor cell functions mediating disease progression. Transfection of a miR-1469 mimic resulted in a significant reduction in the migratory and invasive capacity of the CHL1 and MEL39 melanoma cell lines (>58.1% reduction, p < 0.0332), as well as the invasive capacity of the A375 melanoma cell line (>50% reduction, p < 0.0021). Expression of myeloid cell leukemia-1 (MCL1), a miR-1469 target gene, was reduced in the A375 and MEL39 cell lines by immunoblot. No significant differences in viability, resistance to apoptotic stimuli, or proliferation were observed following transfection. These findings together demonstrate how migration and invasion are specific functions through which miR-1469 expression in melanoma cells can contribute to the differences in disease progression associated with tumor ulceration.

Soy-tomato enriched diet reduces inflammation and disease severity in a pre-clinical model of chronic pancreatitis.

Chronic pancreatitis (CP) is a fibro-inflammatory syndrome in individuals who develop persistent pathological responses to parenchymal injury or stress. Novel therapeutic or dietary interventions that could lessen inflammation in this disease could significantly improve quality of life in patients with CP. Complex dietary foods like soy and tomatoes are composed of active metabolites with anti-inflammatory effects. Data from our group reports that bioactive agents in soy and tomatoes can reduce pro-inflammatory cytokines and suppressive immune populations. Additionally, our team has developed a novel soy-tomato juice currently being studied in healthy individuals with no toxicities, and good compliance and bioavailability. Thus, we hypothesize that administration of a soy-tomato enriched diet can reduce inflammation and severity of CP. C57BL/6 mice were injected intraperitoneally with 50 µg/kg caeurlein (7 hourly injections, twice weekly) for 6 weeks to induce CP. After 4 weeks of caerulein injections, mice were administered a control or a soy-tomato enriched diet for 2 weeks. Disease severity was measured via immunohistochemical analysis of pancreata measuring loss of acini, fibrosis, inflammation, and necrosis. Serum lipase and amylase levels were analyzed at the end of the study. Inflammatory factors in the serum and pancreas, and immune populations in the spleen of mice were analyzed by cytokine multiplex detection, qRT-PCR, and flow cytometry respectively. Infra-red (IR) sensing of mice was used to monitor spontaneous activity and distress of mice. Mice fed a soy-tomato enriched diet had a significantly reduced level of inflammation and severity of CP (p = 0.032) compared to mice administered a control diet with restored serum lipase and amylase levels (p < 0.05). Mice with CP fed a soy-tomato diet had a reduction in inflammatory factors (TNF-α, IL-1ß, IL-5) and suppressive immune populations (myeloid-derived suppressor cells; MDSC) compared to control diet fed mice (p < 0.05). Infra-red sensing to monitor spontaneous activity of mice showed that soy-tomato enriched diet improved total activity and overall health of mice with CP (p = 0.055) and CP mice on a control diet were determined to spend more time at rest (p = 0.053). These pre-clinical results indicate that a soy-tomato enriched diet may be a novel treatment approach to reduce inflammation and pain in patients with CP.

Tissue microRNA expression profiling in hepatic and pulmonary metastatic melanoma.

Malignant melanoma has a propensity for the development of hepatic and pulmonary metastases. MicroRNAs (miRs) are small, noncoding RNA molecules containing about 22 nucleotides that mediate protein expression and can contribute to cancer progression. We aim to identify clinically useful differences in miR expression in metastatic melanoma tissue. RNA was extracted from formalin-fixed, paraffin-embedded samples of hepatic and pulmonary metastatic melanoma, benign, nevi, and primary cutaneous melanoma. Assessment of miR expression was performed on purified RNA using the NanoString nCounter miRNA assay. miRs with greater than twofold change in expression when compared to other tumor sites (P value ≤ 0.05, modified t-test) were identified as dysregulated. Common gene targets were then identified among dysregulated miRs unique to each metastatic site. Melanoma metastatic to the liver had differential expression of 26 miRs compared to benign nevi and 16 miRs compared to primary melanoma (P < 0.048). Melanoma metastatic to the lung had differential expression of 19 miRs compared to benign nevi and 10 miRs compared to primary melanoma (P < 0.024). Compared to lung metastases, liver metastases had greater than twofold upregulation of four miRs, and 4.2-fold downregulation of miR-200c-3p (P < 0.0081). These findings indicate that sites of metastatic melanoma have unique miR profiles that may contribute to their development and localization. Further investigation of the utility of these miRs as diagnostic and prognostic biomarkers and their impact on the development of metastatic melanoma is warranted.

Effects of Colonization of Gnotobiotic Swiss Webster Mice with Helicobacter bilis.

Helicobacter bilis (Hb) causes hepatitis in some strains of inbred mice. The current study confirmed that Hb directly causes portal hepatitis in outbred gnotobiotic Swiss Webster (SW) mice, as we previously reported for conventional SW mice. Hbmonoassociated SW mice also developed mild enterocolitis, expanded gut-associated lymphoid tissue (GALT), and tertiary lymphoid tissue in the lower bowel. At 1 and 10 mo after infection, Hb-induced GALT hyperplasia exhibited well-organized, ectopic germinal centers with increased mononuclear cell apoptosis, MHC class II antigen presentation, and pronounced endothelial venule formation, consistent with features of tertiary lymphoid tissue. In the lower bowel, Hb induced mainly B220+ cells as well as CD4+ IL17+, CD4+ IFNγ+, and CD4+ FoxP3+ regulatory T cells and significantly increased IL10 mRNA expression. This gnotobiotic model confirmed that Hb causes portal hepatitis in outbred SW mice but stimulated GALT with an antiinflammatory bias. Because Hb had both anti- and proinflammatory effects on GALT, it should be considered a 'pathosymbiont provocateur' and merits further evaluation in mouse models of human disease.

Alterations in patient plasma microRNA expression profiles following resection of metastatic melanoma.

BACKGROUND AND OBJECTIVES: MicroRNAs (miRs) are noncoding RNAs that regulate protein translation and melanoma progression. Changes in plasma miR expression following surgical resection of metastatic melanoma are under-investigated. We hypothesize differences in miR expression exist following complete surgical resection of metastatic melanoma. METHODS: Blood collection pre- and post-surgical resection was performed in six individuals with solitary melanoma metastases. miR expression in extracted RNA was quantified using the NanoString nCounter Digital Analyzer. RESULTS: Pre- and post-surgical plasma samples contained 216 miRs with expression above baseline. Comparison of postsurgical to preresection samples revealed differential expression of 25 miRs: miR-let-7a, miR-let7g, miR-15a, miR-16, miR-22, miR-30b, miR-126, miR-140, miR-145, miR-148a, miR-150-5p, miR-191, miR-378i, miR-449c, miR-494, miR-513b, miR-548aa, miR-571, miR-587, miR-891b, miR-1260a, miR 1268a, miR-1976, miR-4268, miR-4454 (P < 0.05). Utilizing P < 0.0046 as a cutoff to control for one false positive among the 216 miRs revealed that postsurgical melanoma plasma samples had upregulation of miR-1260a (P = 0.0007) and downregulation of miR-150-5p (P = 0.0026) relative to pre-surgical samples. CONCLUSIONS: Differential expression of miR-150-5p and miR-1260a is present in plasma following surgical resection of metastatic melanoma in this small sample (n = 6) of melanoma patients. Therefore, further investigation of these plasma miRs as noninvasive biomarkers for melanoma is warranted.

Metallosis in a Dog as a Long-Term Complication Following Total Hip Arthroplasty.

Metallosis is the accumulation of metallic debris in soft tissues resulting from wear following total joint replacement. A dog was evaluated for lameness 4 years after total hip arthroplasty using a titanium alloy and cobalt chromium total hip system. Radiographs revealed severe acetabular component wear, implant-bone interface deterioration, and peri-acetabular osteolysis. During surgical revision, black periarticular tissue surrounded the implants. Histologically, there was fibrosis and granulomatous inflammation with abundant, intra- and extracellular, black, granular material and smaller amounts of clear punctate to acicular material. Laser capture microdissection followed by x-ray fluorescence microscopy indicated the material contained large amounts of titanium with smaller amounts of vanadium, cobalt, and chromium, confirming the diagnosis of metallosis. The clear material was birefringent under cross-polarized light, stained positive with Oil-Red-O, and thus was consistent with polyethylene. Metallosis exhibits characteristic gross and histologic lesions and is a differential diagnosis for aseptic loosening of hip implants.