Cytotoxic lymphocytes interact with human tumor cells via the activating immunoreceptor NKG2D, recognizing a variety of stress-associated MIC and ULBP surface molecules. However, tumors can escape ...from this immunosurveillance by shedding NKG2D ligands (NKG2DL), rendering the soluble products detectable in patients' sera.
To elucidate the clinical significance of NKG2DL diversity, we studied their expression on melanoma tissues and their presence as soluble molecules in sera from >200 melanoma patients and compared the latter with the well-established serum marker S100B.
Immunohistochemistry revealed a heterogeneous expression of MIC and ULBP2 molecules between and within melanoma metastases. Compared with MIC, ULBP2 was less frequently expressed. Accordingly, elevated levels of soluble ULBP2 (sULBP2) were detected in sera of melanoma patients less frequently than elevated levels of soluble MICA (sMICA), although both soluble NKG2DL (sNKG2DL) were significantly increased compared with sera of healthy controls (P < 0.0001). Strikingly, elevated concentrations of sULBP2, but not of sMICA, were strongly associated with disease progression (P < 0.0001) and tumor load (P = 0.0003). Elevated serum levels of either sNKG2DL correlated with reduced overall survival, albeit considerably stronger for sULBP2 (P < 0.0001) than for sMICA (P = 0.011). In early-stage (I-III) melanoma patients, only sULBP2 (P < 0.0001) but neither sMICA nor S100B revealed prognostic significance. Multivariate analysis identified sULBP2 (P = 0.0015) and S100B (P = 0.013) but not sMICA as independent predictors of prognosis.
Our data reveal marked differences in the clinical significance of individual sNKG2DL. Only sULBP2 is an independent predictor of prognosis, the significance of which is superior to the well-established and widely used melanoma serum marker S100B.
Intorduction
Chondroitin sulfate proteoglycan 4 (CSPG4), also known as high molecular weight-melanoma associated antigen, is expressed in melanoma but also other tumor entities and constitutes an ...attractive target for immunotherapeutic approaches. While recent preclinical reports focused on anti-CSPG4 chimeric antigen receptors (CAR), we here explore T-cell receptor (TCR)-based approaches targeting CSPG4.
Methods
The TCRs of two CSPG4-reactive T-cell clones (11C/73 and 2C/165) restricted by the highly prevalent HLA-C*07:01 allele were isolated and the respective αβTCR pairs were retrovirally expressed in CRISPR/Cas9-edited TCR-knockout T cells for functional testing. We also combined alpha and beta TCR chains derived from 11C/73 and 2C/165 in a cross-over fashion to assess for hemichain dominance. CSPG4
+
melanoma, glioblastoma and lung cancer cell lines were identified and, if negative, retrovirally transduced with HLA-C*07:01.
Results
Functional tests confirmed specific recognition of CSPG4
+
HLA-C*07:01
+
target cells by the αβTCR retrieved from the parental T-cell clones and in part also by the cross-over TCR construct 2Cα-11Cβ. Despite high surface expression, the 11Cα-2Cβ combination, however, was not functional.
Discussion
Collectively, 11C/73- and 2C/165-expressing T cells specifically and efficiently recognized CSPG4
+
HLA-C*07:01
+
cancer cells which warrants further preclinical and clinical evaluation of these TCRs.
Chemotherapeutic drugs are clinically used to treat cancer because of their cytotoxic activities against tumor cells. Recently, however, evidence is accumulating—including the report of Hervieu et ...al. (2012) in the current issue of The Journal of Investigative Dermatology—indicating that at least some of these drugs have broader activities and that they should also be considered immunomodulatory agents. Indeed, Hervieu demonstrates that dacarbazine (DTIC) exerts immunostimulatory effects by inducing local activation of natural killer (NK) and T cells, suggesting that upon treatment with DTIC, the tumor participates in the initiation of an immune response: (i) DTIC treatment elicits the expression of ligands of the immunoreceptor NKG2D on melanoma cells; (ii) engagement of the ligands by NKG2D on NK cells leads to their activation, allowing enhanced tumor-cell killing and the release of IFN-γ; and (iii) IFN-γ in turn upregulates major histocompatibility complex class I expression on tumor cells, which favors their recognition by cytotoxic CD8+ T lymphocytes (CTLs).
Combination immunotherapy (CIT) is currently applied as a treatment for different cancers and is proposed as a cure strategy for chronic viral infections. Whether such therapies are efficient during ...an acute infection remains elusive. To address this, inhibitory receptors were blocked and regulatory T cells depleted in acutely Friend retrovirus-infected mice. CIT resulted in a dramatic expansion of cytotoxic CD4+ and CD8+ T cells and a subsequent reduction in viral loads. Despite limited viral replication, mice developed fatal immunopathology after CIT. The pathology was most severe in the gastrointestinal tract and was mediated by granzyme B producing CD4+ and CD8+ T cells. A similar post-CIT pathology during acute Influenza virus infection of mice was observed, which could be prevented by vaccination. Melanoma patients who developed immune-related adverse events under immune checkpoint CIT also presented with expanded granzyme-expressing CD4+ and CD8+ T cell populations. Our data suggest that acute infections may induce immunopathology in patients treated with CIT, and that effective measures for infection prevention should be applied.
Background Screening for gene mutations has become routine clinical practice across numerous tumor entities, including melanoma. BAP1 gene mutations have been identified in various tumor types and ...acknowledged as a critical event in metastatic uveal melanoma, but their role in non-uveal melanoma remains inadequately characterized. Methods A retrospective analysis of all melanomas sequenced in our department from 2014–2022 (n=2650) was conducted to identify BAP1 mutated samples. Assessment of clinical and genetic characteristics was performed as well as correlations with treatment outcome. Results BAP1 mutations were identified in 129 cases and distributed across the entire gene without any apparent hot spots. Inactivating BAP1 mutations were more prevalent in uveal (55%) compared to non-uveal (17%) melanomas. Non-uveal BAP1 mutated melanomas frequently exhibited UV-signature mutations and had a significantly higher mutation load than uveal melanomas. GNAQ and GNA11 mutations were common in uveal melanomas, while MAP-Kinase mutations were frequent in non-uveal melanomas with NF1 , BRAF V600 and NRAS Q61 mutations occurring in decreasing frequency, consistent with a strong UV association. Survival outcomes did not differ among non-uveal melanoma patients based on whether they received targeted or immune checkpoint therapy, or if their tumors harbored inactivating BAP1 mutations. Conclusion In contrast to uveal melanomas, where BAP1 mutations serve as a significant prognostic indicator of an unfavorable outcome, BAP1 mutations in non-uveal melanomas are primarily considered passenger mutations and do not appear to be relevant from a prognostic or therapeutic perspective.
CD4+ helper T cells and cytotoxic CD8+ T cells are key players for adaptive immune responses against acute infections with retroviruses. Similar to textbook knowledge the most important function of ...CD4+ T cells during an acute retrovirus infection seems to be their helper function for other immune cells. Whereas there was no direct anti-viral activity of CD4+ T cells during acute Friend Virus (FV) infection, they were absolutely required for the control of chronic infection. During chronic FV infection a population of activated FV-specific CD4+ T cells did not express cytotoxic molecules, but Fas Ligand that can induce Fas-induced apoptosis in target cells. Using an MHC II-restricted in vivo CTL assay we demonstrated that FV-specific CD4+ T cells indeed mediated cytotoxic effects against FV epitope peptide loaded targets. CD4 + CTL killing was also detected in FV-infected granzyme B knockout mice confirming that the exocytosis pathway was not involved. However, killing could be blocked by antibodies against FasL, which identified the Fas/FasL pathway as critical cytotoxic mechanism during chronic FV infection. Interestingly, targeting the co-stimulatory receptor CD137 with an agonistic antibody enhanced CD4+ T cell cytotoxicity. This immunotherapy may be an interesting new approach for the treatment of chronic viral infections.
Cutaneous vascular tumors consist of a heterogeneous group of benign proliferations, including a range of hemangiomas and vascular malformations, as well as heterogeneous groups of both borderline ...and malignant neoplasms such as Kaposi’s sarcoma and angiosarcomas. The genetics of these tumors have been assessed independently in smaller individual cohorts making comparisons difficult. In our study, we analyzed a representative cohort of benign vascular proliferations observed in a clinical routine setting as well as a selection of malignant vascular proliferations. Our cohort of 104 vascular proliferations including hemangiomas, malformations, angiosarcomas and Kaposi’s sarcoma were screened by targeted next-generation sequencing for activating genetic mutations known or assumed to be potentially relevant in vascular proliferations. An association analysis was performed for mutation status and clinico-pathological parameters. Frequent activating hotspot mutations in
GNA
genes, including
GNA14
Q205,
GNA11
and
GNAQ
Q209 were identified in 16 of 64 benign vascular tumors (25%).
GNA
gene mutations were particularly frequent (52%) in cherry (senile) hemangiomas (13 of 25). In angiosarcomas, activating
RAS
mutations (
HRAS
and
NRAS
) were identified in three samples (16%). No activating
GNA
or
RAS
gene mutations were identified in Kaposi’s sarcomas. Our study identifies
GNA14
Q205,
GNA11
and
GNAQ
Q209 mutations as being the most common and mutually exclusive mutations in benign hemangiomas. These mutations were not identified in malignant vascular tumors, which could be of potential diagnostic value in distinguishing these entities.
Immune activation within the tumor microenvironment is one promising approach to induce tumor regression. Certain viruses including oncolytic viruses such as the herpes simplex virus (HSV) and ...non-oncolytic viruses such as the lymphocytic choriomeningitis virus (LCMV) are potent tools to induce tumor-specific immune activation. However, not all tumor types respond to viro- and/or immunotherapy and mechanisms accounting for such differences remain to be defined. In our current investigation, we used the non-cytopathic LCMV in different human melanoma models and found that melanoma cell lines produced high levels of CCL5 in response to immunotherapy.
, robust CCL5 production in LCMV infected Ma-Mel-86a tumor bearing mice led to recruitment of NK cells and fast tumor regression. Lack of NK cells or CCL5 abolished the anti-tumoral effects of immunotherapy. In conclusion, we identified CCL5 and NK cell-mediated cytotoxicity as new factors influencing melanoma regression during virotherapy.
Exosomes are cell-secreted nanovesicles (40-200 nm) that represent a rich source of novel biomarkers in the diagnosis and prognosis of certain diseases. Despite the increasingly recognized relevance ...of these vesicles as biomarkers, their detection has been limited due in part to current technical challenges in the rapid isolation and analysis of exosomes. The complexity of the development of analytical platforms relies on the heterogeneous composition of the exosome membrane. One of the most attractive tests is the inmunochromatographic strips, which allow rapid detection by unskilled operators. We have successfully developed a novel lateral flow immunoassay (LFIA) for the detection of exosomes based on the use of tetraspanins as targets. We have applied this platform for the detection of exosomes purified from different sources: cell culture supernatants, human plasma and urine. As proof of concept, we explored the analytical potential of this LFIA platform to accurately quantify exosomes purified from a human metastatic melanoma cell line. The one-step assay can be completed in 15 min, with a limit of detection of 8.54×10
5
exosomes/µL when a blend of anti-CD9 and anti-CD81 were selected as capture antibodies and anti-CD63 labelled with gold nanoparticles as detection antibody. Based on our results, this platform could be well suited to be used as a rapid exosome quantification tool, with promising diagnostic applications, bearing in mind that the detection of exosomes from different sources may require adaptation of the analytical settings to their specific composition.
(1) Background: Melanoma has the highest mortality of all cutaneous tumors, despite recent treatment advances. Many relevant genetic events have been identified in the last decade, including ...recurrent
mutations, which in various tumors have been associated with improved outcomes to immunotherapy. (2) Methods: Retrospective analysis of 116 melanoma samples harboring
mutations. Assessment of clinical and genetic characteristics was performed as well as correlations with treatment outcome applying Kaplan-Meier (log-rank test), Fisher's exact and Chi-squared tests. (3) Results: The majority of
mutations were in cutaneous and occult melanoma.
mutated samples had a higher number of mutations than
wild-type samples and harbored UV-mutations. A male predominance was observed. Many samples also harbored
mutations. No apparent differences were noted between samples harboring genetically inactivating (frame-shift or nonsense) mutations and samples with other mutations. No differences in survival or response to immunotherapy of patients with
mutant melanoma were observed. (4) Conclusions:
mutations primarily occur in cutaneous melanomas with a higher mutation burden. In contrast to findings in other tumors, our data does not support
mutations being a biomarker of favorable response to immunotherapies in melanoma. Larger prospective studies would still be warranted.
PDF
