Adenosine-deaminase-acting-on-RNA-1 facilitates T-cell migration toward human melanoma cells

The effect of tumor/T-cell interactions on subsequent immune infiltration is undefined. Here we report that pre-exposure of melanoma cells to cognate T cells enhanced the chemotaxis of new T cells in vitro. The effect was HLA class I-restricted and IFNγ-dependent, as it was abolished by β2M-knockdown, MHC-blocking antibodies, JAK1 inhibitors, JAK1-silencing and IFNgR1-blocking antibodies. RNA-sequencing of 73 melanoma metastases showed a significant correlation between the interferon-inducible p150 isoform of adenosine-deaminase-acting-on-RNA-1 (ADAR1) enzyme and immune infiltration. Consistent with this, co-cultures of cognate melanoma/T-cell pairs led to IFNγ-dependent induction of ADAR1-p150 in the melanoma cells, as visualized in situ using dynamic cell blocks, in ovo using fertilized chick eggs, and in vitro with Western blots. ADAR1 staining and RNA-sequencing in patient-derived biopsies following immunotherapy showed a rise in ADAR1-p150 expression concurrently with CD8+ cell infiltration and clinical response. Silencing ADAR1-p150 abolished the IFNγ-driven enhanced T-cell migration, confirming its mechanistic role. Silencing and overexpression of the constitutive isoform of ADAR1, ADAR1-p110, decreased and increased T-cell migration, respectively. Chemokine arrays showed that ADAR1 controls the secretion of multiple chemokines from melanoma cells, probably through microRNA-mediated regulation. Chemokine receptor blockade eliminated the IFNγ-driven T-cell chemotaxis. We propose that the constitutive ADAR1 downregulation observed in melanoma contributes to immune exclusion, whereas antigen-specific T cells induce ADAR1-p150 by releasing IFNγ, which can drive T-cell infiltration.

microRNA expression patterns in tumor infiltrating lymphocytes are strongly associated with response to adoptive cell transfer therapy

Adoptive cell transfer (ACT) using autologous tumor infiltrating lymphocytes (TILs) was previously shown to yield clinical response in metastatic melanoma patients as an advanced line. Unfortunately, there is no reliable marker for predicting who will benefit from the treatment. We analyzed TIL samples from the infusion bags used for treatment of 57 metastatic melanoma patients and compared their microRNA profiles. The discovery cohort included six responding patients and seven patients with progressive disease, as defined by RECIST1.1. High throughput analysis with NanoString nCounter demonstrated significantly higher levels of miR-34a-5p and miR-22-3p among TIL from non-responders. These results were validated in TIL infusion bag samples from an independent cohort of 44 patients, using qRT-PCR of the individual microRNAs. Using classification trees, a data-driven predictive model for response was built, based on the level of expression of these microRNAs. Patients that achieved stable disease were classified with responders, setting apart the patients with progressive disease. Moreover, the expression levels of miR-34a-5p in the infused TIL created distinct survival groups, which strongly supports its role as a potential biomarker for TIL-ACT therapy. Indeed, when tested against autologous melanoma cells, miR^Low TIL cultures exhibited significantly higher cytotoxic activity than miR^High TIL cultures, and expressed features of terminally exhausted effectors. Finally, overexpression of miR-34a-5p or miR-22-3p in TIL inhibited their cytotoxic ability in vitro. Overall, we show that a two-microRNA signature correlates with failure of TIL-ACT therapy and survival in melanoma patients.

Histopathological expression analysis of intercellular adhesion molecule 1 (ICAM-1) along development and progression of human melanoma

Intercellular adhesion molecule 1 (ICAM-1) protein is an important adhesion molecule that facilitates metastasis on one hand, and on the other hand supports the immunological synapse necessary for T-cell mediated elimination. The expression pattern of ICAM-1 in melanoma was studied more than two decades ago, mainly in cell lines or in unmatched melanoma specimens. By using real time PCR we could not demonstrate a clear difference in ICAM-1 mRNA levels between primary melanocytes and primary cultures of metastatic melanoma. However, immunohistochemistry staining of progression tissue microarray comprised of samples of different disease stages derived from different patients, demonstrated a dramatic ICAM-1 upregulation particularly upon the transition from primary tumor to lymph node metastasis. There was no significant difference between lymph node and distant metastases. Importantly, these results were confirmed in an independent tissue microarray comprised of patient-paired specimens from progressive stages of the patient’s disease. These data indicate that ICAM-1 upregulation is required to initiate the lymphatic spread of melanoma (Stage III) but no further increase is associated with progression to remote organs (Stage IV).

CEACAM1 and MICA as novel serum biomarkers in patients with acute and recurrent pericarditis

Background

The immune response plays a significant role in pericarditis, but the mechanisms of disease are poorly defined. Further, efficient monitoring and predictive clinical tools are unavailable. Carcinoembryonic antigen cell adhesion molecule 1 (CEACAM1) is an immune-inhibitory protein, while MHC class I chain related protein A (MICA) and B (MICB) have an immune-stimulating function.

Methods and results

Serum CEACAM1, MICA and MICB concentrations were measured by ELISA in ∼50 subjects of each group: acute pericarditis (AP), recurrent pericarditis (RP) and lupus (SLE) patients, metastatic melanoma patients as well as healthy donors. Serum CEACAM1 was dramatically elevated in AP and RP patients, but not in SLE patients, and displayed a highly accurate profile in ROC curve analyses. MICA and MICB were elevated in some pericarditis patients. All markers were enhanced in metastatic melanoma patients irrespective of neoplastic pericardial involvement. Etiology-guided analysis of RP patients showed that very low MICA levels were associated with idiopathic RP, while high MICA was associated with autoimmune and post-operative RP. Importantly, MICA was significantly associated with recurrences, independently of other potentially confounding parameters such as age, time of follow up or treatment modality.

Conclusions

Here we report for the first time on CEACAM1 as a potentially novel biomarker for pericarditis, as well as on MICA as an innovative prognostic marker in these patients. Determination of the roles of these immune factors, as well as their diagnostic and prognostic values should be determined in future prospective studies.

Increased serum NKG2D-ligands and downregulation of NKG2D in peripheral blood NK cells of patients with major burns

Immune suppression following major thermal injury directly impacts the recovery potential. Limited data from past reports indicate that natural killer cells might be suppressed due to a putative soluble factor that has remained elusive up to date. Here we comparatively study cohorts of patients with Major and Non-Major Burns as well as healthy donors. MICB and ULBP1 are stress ligands of NKG2D that can be induced by heat stress. Remarkably, serum concentration levels of MICB and ULBP1 are increased by 3-fold and 20-fold, respectively, already within 24h post major thermal injury, and are maintained high for 28 days. In contrast, milder thermal injuries do not similarly enhance the serum levels of MICB and ULBP1. This kinetics coincides with a significant downregulation of NKG2D expression among peripheral blood NK cells. Downregulation of NKG2D by high concentration of soluble MICB occurs in cancer patients and during normal pregnancy due to over production by cancer cells or extravillous trophoblasts, respectively, as an active immune-evasion mechanism. In burn patients this seems an incidental outcome of extensive thermal injury, leading to reduced NKG2D expression. Enhanced susceptibility of these patients to opportunistic viral infections, particularly herpes viruses, could be explained by the reduced NKG2D expression. Further studies are warranted for translation into innovative diagnostic or therapeutic technologies.

A novel immune resistance mechanism of melanoma cells controlled by the ADAR1 enzyme

The blossom of immunotherapy in melanoma highlights the need to delineate mechanisms of immune resistance. Recently, we have demonstrated that the RNA editing protein, adenosine deaminase acting on RNA-1 (ADAR1) is down-regulated during metastatic transition of melanoma, which enhances melanoma cell proliferation and tumorigenicity. Here we investigate the role of ADAR1 in melanoma immune resistance.Importantly, knockdown of ADAR1 in human melanoma cells induces resistance to tumor infiltrating lymphocytes in a cell contact-dependent mechanism. We show that ADAR1, in an editing-independent manner, regulates the biogenesis of miR-222 at the transcription level and thereby Intercellular Adhesion Molecule 1 (ICAM1) expression, which consequently affects melanoma immune resistance. ADAR1 thus has a novel, pivotal, role in cancer immune resistance. Corroborating with these results, the expression of miR-222 in melanoma tissue specimens was significantly higher in patients who had no clinical benefit from treatment with ipilimumab as compared to patients that responded clinically, suggesting that miR-222 could function as a biomarker for the prediction of response to ipilimumab.These results provide not only novel insights on melanoma immune resistance, but also pave the way to the development of innovative personalized tools to enable optimal drug selection and treatment.

CEACAM1 promotes melanoma cell growth through Sox-2

The prognostic value of the carcinoembryonic antigen cell adhesion molecule 1 (CEACAM1) in melanoma was demonstrated more than a decade ago as superior to Breslow score. We have previously shown that intercellular homophilic CEACAM1 interactions protect melanoma cells from lymphocyte-mediated elimination. Here, we study the direct effects of CEACAM1 on melanoma cell biology. By employing tissue microarrays and low-passage primary cultures of metastatic melanoma, we show that CEACAM1 expression gradually increases from nevi to metastatic specimens, with a strong dominance of the CEACAM1-Long tail splice variant. Using experimental systems of CEACAM1 knockdown and overexpression of selective variants or truncation mutants, we prove that only the full-length long tail variant enhances melanoma cell proliferation in vitro and in vivo. This effect is not reversed with a CEACAM1-blocking antibody, suggesting that it is not mediated by intercellular homophilic interactions. Downstream, CEACAM1-Long increases the expression of Sox-2, which we show to be responsible for the CEACAM1-mediated enhanced proliferation. Furthermore, analysis of the CEACAM1 promoter reveals two single-nucleotide polymorphisms (SNPs) that significantly enhance the promoter's activity compared with the consensus nucleotides. Importantly, case-control genetic SNP analysis of 134 patients with melanoma and matched healthy donors show that patients with melanoma do not exhibit the Hardy-Weinberg balance and that homozygous SNP genotype enhances the hazard ratio to develop melanoma by 35%. These observations shed new mechanistic light on the role of CEACAM1 in melanoma, forming the basis for development of novel therapeutic and diagnostic technologies.

CXCR1 as a novel target for directing reactive T cells toward melanoma: implications for adoptive cell transfer immunotherapy

Adoptive cell transfer therapy with reactive T cells is one of the most promising immunotherapeutic modalities for metastatic melanoma patients. Homing of the transferred T cells to all tumor sites in sufficient numbers is of great importance. Here, we seek to exploit endogenous chemotactic signals in order to manipulate and enhance the directional trafficking of transferred T cells toward melanoma. Chemokine profiling of 15 melanoma cultures shows that CXCL1 and CXCL8 are abundantly expressed and secreted from melanoma cultures. However, the complimentary analysis on 40 melanoma patient-derived tumor-infiltrating lymphocytes (TIL) proves that the corresponding chemokine receptors are either not expressed (CXCR2) or expressed at low levels (CXCR1). Using the in vitro transwell system, we demonstrate that TIL cells preferentially migrate toward melanoma and that endogenously expressing CXCR1 TIL cells are significantly enriched among the migrating lymphocytes. The role of the chemokines CXCL1 and CXCL8 is demonstrated by partial abrogation of this enrichment with anti-CXCL1 and anti-CXCL8 neutralizing antibodies. The role of the chemokine receptor CXCR1 is validated by the enhanced migration of CXCR1-engineered TIL cells toward melanoma or recombinant CXCL8. Cytotoxicity and IFNγ secretion activity are unaltered by CXCR1 expression profile. Taken together, these results mark CXCR1 as a candidate for genetic manipulations to enhance trafficking of adoptively transferred T cells. This approach is complimentary and potentially synergistic with other genetic strategies designed to enhance anti-tumor potency.

The leucine rich repeat kinase 2 (LRRK2) G2019S substitution mutation. Association with Parkinson disease, malignant melanoma and prevalence in ethnic groups in Israel

BACKGROUND

A single missense mutation (G2019S) in the leucine rich repeat kinase 2 (LRRK2) gene has been reported to be prevalent among Ashkenazi Jewish patients with Parkinson disease (PD). An association between malignant melanoma (MM) and PD was also recently reported. The nature of this association is still elusive.

OBJECTIVE

To evaluate the rate of the G2019S(*) LRKK2 mutation among ethnically diverse, Jewish PD patients, MM patients, and Ashkenazi, Iraqi and Moroccan healthy controls.

PATIENTS AND METHODS

Overall, 242 Jewish PD patients (155 Ashkenazim and 7 of mixed origin) and 169 Jewish MM patients (142 Ashkenazim) were genotyped for the G2019S mutation. In addition, 900 healthy ethnic Jewish controls (300 Ashkenazim, 300 Moroccans and 300 Iraqis) were similarly analyzed. Genotyping was performed using PCR amplification followed by restriction digest and gel electrophoresis. Statistical analysis was done using the Chi square test.

RESULTS

Overall 19/242 (7.9 %) of the PD patients (16/155 of Ashkenazim, 10.3 %; 3/87 of non-Ashkenazim, 3.4 %) harbored the G2019S LRKK2 mutation. The age at diagnosis of PD in mutation carriers was 60.6 +/- 10.9 years compared with an age at diagnosis of 61.1 +/- 13.4 years in non-carriers (p = 0.87). Nine of 38 familial Ashkenazi PD patients (23.68 %) carried the mutation, as did 2/169 MM patients (1.2 %; 2/142, 1.4 % of the Ashkenazim). A single mutation carrier of Ashkenazi origin was detected among 900 controls (0.3 % of the Ashkenazi controls).

CONCLUSION

The G2019S*LRKK2 mutation is significantly more prevalent in Ashkenazi PD patients than in controls (p = 1 x 10(-6)), it is less commonly detected in non-Ashkenazi affected individuals, and its contribution to MM predisposition in Jewish individuals needs to be explored further.