CRISPR-inhibition screen for lncRNAs linked to melanoma growth and metastasis.

Unlabelled: Melanoma being one of the most common and deadliest skin cancers, has been rising since the past decade. Patients at advanced stages of the disease have very poor prognoses, as opposed to at the earlier stages. Nowadays the standard-of-care of advanced melanoma is resection followed by immune checkpoint inhibition based immunotherapy.

Kinase Insert Domain Receptor Q472H Pathogenic Germline Variant Impacts Melanoma Tumor Growth and Patient Treatment Outcomes.

Background: We previously reported a higher incidence of a pathogenic germline variant in the kinase insert domain receptor (KDR) in melanoma patients compared to the general population. Here, we dissect the impact of this genotype on melanoma tumor growth kinetics, tumor phenotype, and response to treatment with immune checkpoint inhibitors (ICIs) or targeted therapy.

Methods: The KDR genotype was determined and the associations between the KDR Q472H variant (KDR-Var), angiogenesis, tumor immunophenotype, and response to MAPK inhibition or ICI treatment were examined.

Genomic and Transcriptomic Analyses of NF1-Mutant Melanoma Identify Potential Targeted Approach for Treatment.

There is currently no targeted therapy to treat NF1-mutant melanomas. In this study, we compared the genomic and transcriptomic signatures of NF1-mutant and NF1 wild-type melanoma to reveal potential treatment targets for this subset of patients. Genomic alterations were verified using qPCR, and differentially expressed genes were independently validated using The Cancer Genome Atlas data and immunohistochemistry.

The histone demethylase PHF8 regulates TGFβ signaling and promotes melanoma metastasis.

The contribution of epigenetic dysregulation to metastasis remains understudied. Through a meta-analysis of gene expression datasets followed by a mini-screen, we identified Plant Homeodomain Finger protein 8 (PHF8), a histone demethylase of the Jumonji C protein family, as a previously unidentified prometastatic gene in melanoma. Loss- and gain-of-function approaches demonstrate that PHF8 promotes cell invasion without affecting proliferation in vitro and increases dissemination but not subcutaneous tumor growth in vivo, thus supporting its specific contribution to the acquisition of metastatic potential.

Functional analysis of RPS27 mutations and expression in melanoma.

Next-generation sequencing has enabled genetic and genomic characterization of melanoma to an unprecedent depth. However, the high mutational background plus the limited depth of coverage of whole-genome sequencing performed on cutaneous melanoma samples make the identification of novel driver mutations difficult. We sought to explore the somatic mutation portfolio in exonic and gene regulatory regions in human melanoma samples, for which we performed targeted sequencing of tumors and matched germline DNA samples from 89 melanoma patients, identifying known and novel recurrent mutations.

Microglandular adenosis is an advanced precursor breast lesion with evidence of molecular progression to matrix-producing metaplastic carcinoma.

Microglandular adenosis (MGA) is a rare breast lesion reported to be associated with invasive carcinoma in up to 20% to 30% of cases and has been proposed as a nonobligate precursor to basal-like breast cancers. We identified a case of matrix-producing metaplastic carcinoma with morphologic and immunohistochemical evidence of progression from MGA to atypical MGA, carcinoma in situ, and invasive carcinoma. We performed whole-exome sequencing of each component (MGA, atypical MGA, carcinoma in situ, and cancer) to characterize the mutational landscape of these foci.

Revisiting the Clinical and Biologic Relevance of Partial PTEN Loss in Melanoma.

The extent of PTEN loss that confers clinical and biological impact in melanoma is unclear. We evaluated the clinical and biologic relevance of PTEN dosage in melanoma and tested the postulate that partial PTEN loss is due to epigenetic mechanisms. PTEN expression was assessed by immunohistochemistry in a stage III melanoma cohort (n = 190) with prospective follow up.

RSK1 activation promotes invasion in nodular melanoma.

The two major melanoma histologic subtypes, superficial spreading and nodular melanomas, differ in their speed of dermal invasion but converge biologically once they invade and metastasize. Herein, we tested the hypothesis that distinct molecular alterations arising in primary melanoma cells might persist as these tumors progress to invasion and metastasis. Ribosomal protein S6 kinase, 90 kDa, polypeptide 1 (RSK1; official name RPS6KA1) was significantly hyperactivated in human melanoma lines and metastatic tissues derived from nodular compared with superficial spreading melanoma.

Melanoma expression of matrix metalloproteinase-23 is associated with blunted tumor immunity and poor responses to immunotherapy.

Background: Matrix metalloproteinase-23 (MMP-23) can block the voltage-gated potassium channel Kv1.3, whose function is important for sustained Ca(2+) signaling during T cell activation. MMP-23 may also alter T cell activity and phenotype through cleavage of proteins affecting cytokine and chemokine signaling.

Serum-based miRNAs in the prediction and detection of recurrence in melanoma patients.

Background: Identification of primary melanoma patients at the highest risk of recurrence remains a critical challenge, and monitoring for recurrent disease is limited to costly imaging studies. We recently reported our array-based discovery of prognostic serum miRNAs in melanoma. In the current study, we examined the clinical utility of these serum-based miRNAs for prognosis as well as detection of melanoma recurrence.

PP6C hotspot mutations in melanoma display sensitivity to Aurora kinase inhibition.

Unlabelled: Recent whole genome melanoma sequencing studies have identified recurrent mutations in the gene encoding the catalytic subunit of serine/threonine phosphatase 6 (PPP6C/PP6C). However, the biochemical, functional, and clinical ramifications of these mutations are unknown. Sequencing PP6C from patients with melanoma (233 primary and 77 metastatic specimens) with extended prospective clinical outcome revealed a large number of hotspot mutations in patients with both primary and metastatic melanoma.

Hedgehog pathway blockade inhibits melanoma cell growth in vitro and in vivo.

Previous reports have demonstrated a role for hedgehog signaling in melanoma progression, prompting us to explore the therapeutic benefit of targeting this pathway in melanoma. We profiled a panel of human melanoma cell lines and control melanocytes for altered expression of hedgehog pathway members and determined the consequences of both genetic and pharmacological inhibition of the hedgehog pathway activator Smoothened (SMO) in melanoma, both in vitro and in vivo. We also examined the relationship between altered expression of hedgehog pathway mediators and survival in a well-characterized cohort of metastatic melanoma patients with prospectively collected follow up information.

Impact of age on the management of primary melanoma patients.

Objectives: Age is an understudied factor when considering treatment options for melanoma. Here, we examine the impact of age on primary melanoma treatment in a prospective cohort of patients.

Methods: We used logistic regression models to examine the associations between age and initial treatment, using recurrence and melanoma-specific survival as endpoints.

T-cell receptor affinity and avidity defines antitumor response and autoimmunity in T-cell immunotherapy.

T cells expressing antigen-specific T-cell receptors (TCRs) can mediate effective tumor regression, but they often also are accompanied by autoimmune responses. To determine the TCR affinity threshold defining the optimal balance between effective antitumor activity and autoimmunity in vivo, we used a unique self-antigen system comprising seven human melanoma gp100(209-217)-specific TCRs spanning physiological affinities (1-100 μM). We found that in vitro and in vivo T-cell responses are determined by TCR affinity, except in one case that was compensated by substantial CD8 involvement.

Serum microRNAs as biomarkers for recurrence in melanoma.

Background: Identification of melanoma patients at high risk for recurrence and monitoring for recurrence are critical for informed management decisions. We hypothesized that serum microRNAs (miRNAs) could provide prognostic information at the time of diagnosis unaccounted for by the current staging system and could be useful in detecting recurrence after resection.

Methods: We screened 355 miRNAs in sera from 80 melanoma patients at primary diagnosis (discovery cohort) using a unique quantitative reverse transcription-PCR (qRT-PCR) panel.

Immune response in melanoma: an in-depth analysis of the primary tumor and corresponding sentinel lymph node.

The sentinel lymph node is the initial site of metastasis. Downregulation of antitumor immunity has a role in nodal progression. Our objective was to investigate the relationship between immune modulation and sentinel lymph node positivity, correlating it with outcome in melanoma patients.

Wild type N-ras displays anti-malignant properties, in part by downregulating decorin.

Previously, we have shown that wild type N-ras (wt N-ras) harbors an anti-malignant effect against mutated Ras and in tumors without Ras mutations. To investigate the molecular bases of this anti-malignant activity, we have studied the potency of this anti-malignant effect in a model system against SV40 large T antigen (SV40T). We show that wild-type N-ras (wt N-ras) counteracts the effects of SV40T in NIH3T3 cells as seen by a decrease in proliferation, anchorage independence and changes in migration.

miR-30b/30d regulation of GalNAc transferases enhances invasion and immunosuppression during metastasis.

To metastasize, a tumor cell must acquire abilities such as the capacity to colonize new tissue and evade immune surveillance. Recent evidence suggests that microRNAs can promote the evolution of malignant behaviors by regulating multiple targets. We performed a microRNA analysis of human melanoma, a highly invasive cancer, and found that miR-30b/30d upregulation correlates with stage, metastatic potential, shorter time to recurrence, and reduced overall survival.

Differential characterization of three alternative spliced isoforms of DPPX.

Transient subthreshold-activating somato-dendritic A-type K(+) currents (I(SA)s) have fundamental roles in neuronal function. They cause delayed excitation, influence spike repolarization, modulate the frequency of repetitive firing, and have important roles in signal processing in dendrites. We previously reported that DPPX proteins are key components of the channels mediating these currents (Kv4 channels) (Nadal, M.

Modification of Kv2.1 K+ currents by the silent Kv10 subunits.

Human and rat Kv10.1a and b cDNAs encode silent K+ channel pore-forming subunits that modify the electrophysiological properties of Kv2.1.

The CD26-related dipeptidyl aminopeptidase-like protein DPPX is a critical component of neuronal A-type K+ channels.

Subthreshold-activating somatodendritic A-type potassium channels have fundamental roles in neuronal signaling and plasticity which depend on their unique cellular localization, voltage dependence, and kinetic properties. Some of the components of A-type K(+) channels have been identified; however, these do not reproduce the properties of the native channels, indicating that key molecular factors have yet to be unveiled. We purified A-type K(+) channel complexes from rat brain membranes and found that DPPX, a protein of unknown function that is structurally related to the dipeptidyl aminopeptidase and cell adhesion protein CD26, is a novel component of A-type K(+) channels.

Cloning of two transcripts, HKT4.1a and HKT4.1b, from the human two-pore K+ channel gene KCNK4. Chromosomal localization, tissue distribution and functional expression.

The human KCNK4 gene encodes several transcripts that generate two-pore K+ channel subunits. We describe the identification and cloning of two transcripts of this gene: human KT4.1a (HKT4.