Plasma Thymidine Kinase Activity as a Novel Biomarker in Metastatic Melanoma Patients Treated with Immune Checkpoint Inhibitors.

Background. Immune checkpoint inhibitors (ICI) are effective in fractions of patients with disseminated melanoma. This study is the first to analyze the plasma activity of thymidine kinase (TK), an enzyme involved in DNA synthesis and repair, as a biomarker in melanoma patients. Methods. Plasma samples were collected prior to treatment start in patients with unresectable metastatic cutaneous melanoma, treated with ICI (anti-CTLA-4 and/or anti-PD-1). Plasma TK activity (TKa) levels were determined using the DiviTum TKa ELISA assay. TKa levels were correlated with patients' baseline characteristics, response rate (RR), progression-free survival (PFS), and overall survival (OS). Results. In the 90 study patients, the median TKa level was 42 Du/L (range <20-1787 Du/L). A significantly higher plasma TKa was found in patients with ECOG performance status ≥1 (p = 0.003), M1c-d disease (p = 0.015), and elevated lactate dehydrogenase levels (p < 0.001). The RR was 63.2% and 30.3% in those with low or high TKa, respectively (p = 0.022). The median PFS was 19.9 and 12.6 months in patients with low or high TKa, respectively (hazard ratio (HR) 1.83 (95% CI, 1.08-3.08), p = 0.024). The median OS was >60 months and 18.5 months in patients with low or high TKa, respectively (HR: 2.25 (95% CI, 1.25-4.05), p = 0.011. Conclusions. High pretreatment plasma TKa levels were significantly associated with worse baseline characteristics and poor response and survival in ICI-treated melanoma patients. TKa is hence a novel and interesting plasma biomarker in melanoma and should be further studied to define its role as a prognostic and predictive marker in this disease.

Extracellular microvesicle microRNAs as predictive biomarkers for targeted therapy in metastastic cutaneous malignant melanoma.

BACKGROUND: Mitogen activated-protein kinase pathway inhibitors (MAPKis) improve treatment outcome in patients with disseminated BRAFV600 mutant cutaneous malignant melanoma (CMM) but responses are of limited duration due to emerging resistance. Although extensive research in mechanisms of resistance is being performed, predictive biomarkers for durable responses are still lacking. We used miRNA qPCR to investigate if different levels of extracellular microvesicle microRNA (EV miRNA) in matched plasma samples collected from patients with metastatic IV BRAFV600 mutated CMM before, during and after therapy with MAPKis could serve as predictive biomarkers. MATERIALS AND METHODS: EV miRNAs were extracted from plasma samples from 28 patients collected before and during therapy, measured by quantitative PCR-array and correlated to therapy outcome. RESULTS: Increased levels of EV let-7g-5p during treatment compared to before treatment (EV let-7g-5p_delta) were associated with better disease control with MAPKis (odds ratio 8568.4, 95% CI = 4.8-1.5e+07, P = 0.000036). Elevated levels of EV miR-497-5p during therapy were associated with prolonged progression free survival (PFS) (hazard ratio = 0.27, 95% CI = 0.13-0.52, P <0.000061). CONCLUSIONS: EV miRNAs let-7g-5p and miR-497-5p were identified as putative novel predictive biomarkers of MAPKi treatment benefit in metastatic CMM patients highlighting the potential relevance of assessing EV miRNA during and after treatment to unravel novel mechanisms of resistance.

Immune gene expression and response to chemotherapy in advanced breast cancer.

BACKGROUND: Transcriptomic profiles have shown promise as predictors of response to neoadjuvant chemotherapy in breast cancer (BC). This study aimed to explore their predictive value in the advanced BC (ABC) setting. METHODS: In a Phase 3 trial of first-line chemotherapy in ABC, a fine needle aspiration biopsy (FNAB) was obtained at baseline. Intrinsic molecular subtypes and gene modules related to immune response, proliferation, oestrogen receptor (ER) signalling and recurring genetic alterations were analysed for association with objective response to chemotherapy. Gene-set enrichment analysis (GSEA) of responders vs non-responders was performed independently. Lymphocytes were enumerated in FNAB smears and the absolute abundance of immune cell types was calculated using the Microenvironment Cell Populations counter method. RESULTS: Gene expression data were available for 109 patients. Objective response to chemotherapy was statistically significantly associated with an immune module score (odds ratio (OR)=1.62; 95% confidence interval (CI), 1.03-2.64; P=0.04). Subgroup analysis showed that this association was restricted to patients with ER-positive or luminal tumours (OR=3.54; 95%, 1.43-10.86; P=0.012 and P for interaction=0.04). Gene-set enrichment analysis confirmed that in these subgroups, immune-related gene sets were enriched in responders. CONCLUSIONS: Immune-related transcriptional signatures may predict response to chemotherapy in ER-positive and luminal ABC.

ΔNp73 regulates the expression of the multidrug-resistance genes ABCB1 and ABCB5 in breast cancer and melanoma cells - a short report.

PURPOSE: Multidrug resistance (MDR) is a major cause of treatment failure. In cancer cells, MDR is often caused by an increased efflux of therapeutic drugs mediated by an up-regulation of ATP binding cassette (ABC) transporters. It has previously been shown that oncogenic ΔNp73 plays an important role in chemo-resistance. Here we aimed at unraveling the role of ΔNp73 in regulating multidrug resistance in breast cancer and melanoma cells. METHODS: KEGG pathway analysis was used to identify pathways enriched in breast cancer samples with a high ΔNp73 expression. We found that the ABC transporter pathway was most enriched. The expression of selected ABC transporters was analyzed using qRT-PCR upon siRNA/shRNA-mediated knockdown or exogenous overexpression of ΔNp73 in the breast cancer-derived cell lines MCF7 and MDA-MB-231, as well as in primary melanoma samples and in the melanoma-derived cell line SK-MEL-28. The ability to efflux doxorubicin and the concomitant effects on cell proliferation were assessed using flow cytometry and WST-1 assays. RESULTS: We found that high ΔNp73 levels correlate with a general up-regulation of ABC transporters in breast cancer samples. In addition, we found that exogenous expression of ΔNp73 led to an increase in the expression of ABCB1 and ABCB5 in the breast cancer-derived cell lines tested, while knocking down of ΔNp73 resulted in a reduction in ABCB1 and ABCB5 expression. In addition, we found that ΔNp73 reduction leads to an intracellular retention of doxorubicin in MDA-MB-231 and MCF7 cells and a concomitant decrease in cell proliferation. The effect of ΔNp73 on ABCB5 expression was further confirmed in metastases from melanoma patients and in the melanoma-derived cell line SK-MEL-28. CONCLUSIONS: Our data support a role for ΔNp73 in the multidrug-resistance of breast cancer and melanoma cells.

Reprogramming Tumor-Associated Macrophages by Antibody Targeting Inhibits Cancer Progression and Metastasis.

Tumors are composed of multiple cell types besides the tumor cells themselves, including innate immune cells such as macrophages. Tumor-associated macrophages (TAMs) are a heterogeneous population of myeloid cells present in the tumor microenvironment (TME). Here, they contribute to immunosuppression, enabling the establishment and persistence of solid tumors as well as metastatic dissemination. We have found that the pattern recognition scavenger receptor MARCO defines a subtype of suppressive TAMs and is linked to clinical outcome. An anti-MARCO monoclonal antibody was developed, which induces anti-tumor activity in breast and colon carcinoma, as well as in melanoma models through reprogramming TAM populations to a pro-inflammatory phenotype and increasing tumor immunogenicity. This anti-tumor activity is dependent on the inhibitory Fc-receptor, FcγRIIB, and also enhances the efficacy of checkpoint therapy. These results demonstrate that immunotherapies using antibodies designed to modify myeloid cells of the TME represent a promising mode of cancer treatment.

Metabolic markers and HSP60 in chemonaive serous solid ovarian cancer versus ascites.

OBJECTIVE: Metabolic pathway alterations in cancer are thought to be dependent upon tumor type-specific oncogenic activation and local nutrient and oxygen supply during disease progression. In serous ovarian cancer, the typical peritoneal spread of disease is caused by shedding of tumor cells into the abdominal cavity, often along with ascites formation. Not much is known about the metabolic features of these detached serous tumor cells. In this study, we investigate the messenger RNA (mRNA) expression of GAPDH (glycolytic glyceraldehyde 3-phosphate dehydrogenase) and PKM2 (pyruvate kinase isoform M2), ATP5B (mitochondrial ß-F1-ATPase), and heat shock protein 60 in matched serous solid tumor and corresponding ascites. MATERIALS/METHODS: Fresh samples from solid tumor and corresponding ascites were prospectively collected from 40 patients undergoing primary surgery for suspected advanced ovarian cancer. Of these, 25 met the study eligibility criteria, that is, stage IIC to IV disease of the serous (24) or endometrioid (1) subtype with solid and ascites specimens containing 50% or more tumor cells and with good quality and quantity mRNA yield. All but 2 patients (92%) had type II disease. GAPDH, PKM2, ATP5B, and HSP60 mRNA expressions were assessed by real-time polymerase chain reaction. For each marker, the mRNA expression in solid tumor was pairwise compared with the corresponding expression in ascites using the Wilcoxon matched pairs signed rank sum test. RESULTS: In contrast to our hypothesis, the mRNA expression of analyzed metabolic markers and HSP60 did not significantly differ between matched solid tumor and malignant ascites. CONCLUSIONS: Our results indicate that further expression changes in genes related to glycolysis or oxidative phosphorylation are not a prerequisite for serous cancer cell survival after detachment.