Role of Nudt2 in Anchorage-Independent Growth and Cell Migration of Human Melanoma.

Nudt2 encodes a diadenosine tetraphosphate (Ap4A) hydrolase that catalyzes the hydrolysis of Ap4A and is involved in the lysyl tRNA synthetase-Ap4A-Nudt2 (LysRS-Ap4A-Nudt2) signaling pathway. We have previously demonstrated that this pathway is active in non-small cell lung cancer. Nudt2 was shown to be involved in cell proliferation in breast cancer, making it an important target in cancer therapy. Currently, the function of Nudt2 in malignant melanoma has not been demonstrated. Therefore, we investigated the role played by Nudt2 in the growth of human melanoma. Our study showed that Nudt2 knockdown suppressed anchorage-independent growth of human melanoma cells in vitro. The in vivo effect of Nudt2 was determined by investigating the role played by Nudt2 knockdown on the ability of the cells to form tumors in a mice xenograft model. Nudt2 knockdown significantly suppressed tumor growth in this model. Moreover, overexpression of Nudt2 resulted in an increase in anchorage-independent growth of these cells, whereas Nudt2 knockdown decreased their migration. In addition, Nudt2 knockdown reduced vimentin expression. Vimentin is one of the mesenchymal markers that are involved in the epithelial mesenchymal transition (EMT) process. Thus, Nudt2 plays an important role in promoting anchorage-independent growth and cell migration in melanoma.

Differential functions of TLE1 and TLE3 depending on a specific phosphorylation site.

Mammalian Transducin-like enhancer of split (TLE) confer global repression of numerous target genes in conjunction with a myriad of DNA-binding repressors. These factors have a major role in the regulation of multiple signal transduction pathways. Evidence have been obtained regarding the possible role of some of these proteins in cancer. TLE3 was suggested as a marker for increased chemosensitivity from pathological studies. Here we demonstrate, using the TCGA data base, differences in expression of this gene compared to TLE1 in several cancers. In-vitro transduction of a retrovirus encoding TLE3 to A549 lung cancer cells increased paclitaxel effectivity while TLE1 introduction to these cells decreased it. While TLE1 and TLE3 share ∼80% amino acid identity, we show that mutating or reconstituting an amino-terminal phosphorylation site, which is present only in TLE1 but absent from TLE3, and is evolutionary conserved, converts the activity of TLE1 to that of TLE3 like and vice versa. We repeated these results in an adipocytes differentiation system. Our results reveal how a single phosphorylation site can confer distinct qualitative or quantitative activities on highly homologous transcriptional regulators.

Circulating neutrophil subsets in advanced lung cancer patients exhibit unique immune signature and relate to prognosis.

The accumulation of circulating low-density neutrophils (LDN) has been described in cancer patients and associated with tumor-supportive properties, as opposed to the high-density neutrophils (HDN). Here we aimed to evaluate the clinical significance of circulating LDN in lung cancer patients, and further assessed its diagnostic vs prognostic value. Using mass cytometry (CyTOF), we identified major subpopulations within the circulating LDN/HDN subsets and determined phenotypic modulations of these subsets along tumor progression. LDN were highly enriched in the low-density (LD) fraction of advanced lung cancer patients (median 7.0%; range 0.2%-80%, n = 64), but not in early stage patients (0.7%; 0.05%-6%; n = 35), healthy individuals (0.8%; 0%-3.5%; n = 15), or stable chronic obstructive pulmonary disease (COPD) patients (1.2%; 0.3%-7.4%, n = 13). Elevated LDN (>10%) remarkably related with poorer prognosis in late stage patients. We identified three main neutrophil subsets which proportions are markedly modified in cancer patients, with CD66b+ /CD10low /CXCR4+ /PDL1inter subset almost exclusively found in advanced lung cancer patients. We found substantial variability in subsets between patients, and demonstrated that HDN and LDN retain a degree of inherent spontaneous plasticity. Deep phenotypic characterization of cancer-related circulating neutrophils and their modulation along tumor progression is an important advancement in understanding the role of myeloid cells in lung cancer.

Structural switch of lysyl-tRNA synthetase between translation and transcription.

Lysyl-tRNA synthetase (LysRS), a component of the translation apparatus, is released from the cytoplasmic multi-tRNA synthetase complex (MSC) to activate the transcription factor MITF in stimulated mast cells through undefined mechanisms. Here we show that Ser207 phosphorylation provokes a new conformer of LysRS that inactivates its translational function but activates its transcriptional function. The crystal structure of an MSC subcomplex established that LysRS is held in the MSC by binding to the N terminus of the scaffold protein p38/AIMP2. Phosphorylation-created steric clashes at the LysRS domain interface disrupt its binding grooves for p38/AIMP2, releasing LysRS and provoking its nuclear translocation. This alteration also exposes the C-terminal domain of LysRS to bind to MITF and triggers LysRS-directed production of the second messenger Ap(4)A that activates MITF. Thus our results establish that a single conformational change triggered by phosphorylation leads to multiple effects driving an exclusive switch of LysRS function from translation to transcription.

Rising Incidence of Lung Cancer in Arab Females, Jewish Females, and Arab Males from 1990 to 2014 in Israel.

BACKGROUND: Lung cancer is the most common cause of cancer-related death. OBJECTIVES: To identify changing patterns of lung cancer and its histologic subtypes among different population groups in Israel over a 25 year period. METHODS: Primary lung cancers, all types and all stages, diagnosed during 1990-2014 were recorded in the Israel National Cancer Registry database. Demographic information was retrieved from the National Population Register. Age-standardized rates for the different subgroups were calculated for each year. Joinpoint software was used to analyze trends in incidence. RESULTS: We identified 42,672 lung cancer cases. The most common histology was adenocarcinoma (34%), followed by squamous cell carcinoma (19%), large cell/not-otherwise-specified (19%), other histologies (15%), and small cell lung cancer (11%). The adenocarcinoma incidence rose from 25.7% to 48.2% during the examined period. Large cell/not-otherwise-specified incidence peaked around 2005-2006 and declined after. Lung cancer incidence increased significantly for the population overall and specifically in Arab females, followed by Jewish females and by Arab males. Adenocarcinoma and small cell lung cancer increased in Jewish females and in Arab males. A younger age of diagnosis was seen in Arab compared to Jewish patients. CONCLUSIONS: Jewish females and Arab males and females living in Israel demonstrated a constant increase in lung cancer incidence, mostly in adenocarcinoma and small cell lung cancer incidence. In addition, a younger age of diagnosis in Arabs was noted. Smoking reduction interventions and screening should be implemented in those populations.

LysRS serves as a key signaling molecule in the immune response by regulating gene expression.

Lysyl-tRNA synthetase (LysRS) was found to produce diadenosine tetraphosphate (Ap(4)A) in vitro more than two decades ago. Here, we used LysRS silencing in mast cells in combination with transfected normal and mutated LysRS to demonstrate in vivo the critical role played by LysRS in the production of Ap(4)A in response to immunological challenge. Upon such challenge, LysRS was phosphorylated on serine 207 in a MAPK-dependent manner, released from the multisynthetase complex, and translocated into the nucleus. We previously demonstrated that LysRS forms a complex with MITF and its repressor Hint-1, which is released from the complex by its binding to Ap(4)A, enabling MITF to transcribe its target genes. Here, silencing LysRS led to reduced Ap(4)A production in immunologically activated cells, which resulted in a lower level of MITF inducible genes. Our data demonstrate that specific LysRS serine 207 phosphorylation regulates Ap(4)A production in immunologically stimulated mast cells, thus implying that LysRS is a key mediator in gene regulation.

New ARCHITECT plasma pro-gastrin-releasing peptide assay for diagnosing and monitoring small-cell lung cancer.

BACKGROUND: Progastrin-releasing peptide (ProGRP) is a potential marker for small-cell lung cancer (SCLC) in serum; however, it may be more stable in plasma. We investigated a new plasma assay (ProGRPp) and its usefulness in diagnosing and monitoring SCLC. METHODS: The marker concentrations were determined on the ARCHITECT i system. RESULTS: The assay could distinguish SCLC from non-small-cell lung cancer (NSCLC: area under the curve 0.931, 95% CI 0.893-0.969; cross-validated accuracy 0.813; sensitivity 84.0%, specificity 96.3%; at 140 pg ml(-1) cutoff). The probability of SCLC when ProGRPp was >140 pg ml(-1) was 91.8%, after adjusting for age, gender, and renal dysfunction. The NSCLC patients with ProGRPp >140 pg ml(-1) were at high risk (odds ratio=37.0, P<0.001) for tumours with neuroendocrine features. False negatives in SCLC were associated with a lack of thyroid transcription factor-1 (P<0.001). A decrease of ProGRPp to <140 pg ml(-1) during chemotherapy was significantly associated with the image-based response (P<0.001), and independently affected progression-free survival (PFS, relative risk=2.51, P=0.04) and overall survival (OS, relative risk=4.38, P=0.003), after adjustment for imaging response, performance status, and stage. CONCLUSIONS: The ProGRPp assay is specific and sensitive for diagnosing SCLC. Changes in ProGRPp during chemotherapy are significantly associated with image-based response, PFS, and OS.

Cabozantinib for metastatic breast carcinoma: results of a phase II placebo-controlled randomized discontinuation study.

PURPOSE: Cabozantinib (XL184), a multi-targeted oral tyrosine kinase inhibitor with activity against MET, VEGFR2, AXL, and other tyrosine kinases, was assessed in a cohort of metastatic breast cancer (MBC) patients in a phase II randomized discontinuation trial (RDT). METHODS: Patients received 100 mg cabozantinib daily during a 12-week lead-in stage. Those with stable disease per modified Response Evaluation Criteria in Solid Tumors version 1.0 at 12 weeks were randomized to either continue cabozantinib or receive placebo. Primary endpoints were objective response rate (ORR) during the 12-week lead-in stage and progression-free survival (PFS) after randomization. Patients were also followed for overall survival (OS). RESULTS: Forty-five patients with MBC and a median of three prior lines of chemotherapy for metastatic disease were enrolled. The ORR during the lead-in stage was 13.6 % (95 % confidence interval [CI] 6-25.7 %), and the disease control rate at week 12 was 46.7 % (95 % CI 31.7-61.6 %). Per the initial RDT study design, patients with stable disease at week 12 were randomized to cabozantinib or placebo. Following a Study Oversight Committee recommendation, randomization was suspended. Patients in the lead-in stage continued on open-label cabozantinib. Patients in the randomization stage were subsequently unblinded. The overall median PFS for all MBC patients was 4.3 months. Median OS was 11.4 months (95 % CI 10.5-16.5 months). The most common grade 3/4 adverse events in the lead-in stage were palmar-plantar erythrodysesthesia (13 %) and fatigue (11 %). One death from respiratory failure was reported as drug-related during the lead-in stage. CONCLUSIONS: In heavily pretreated MBC patients, cabozantinib monotherapy demonstrated clinical activity including objective response and disease control.

A phase IIb trial assessing the addition of disulfiram to chemotherapy for the treatment of metastatic non-small cell lung cancer.

BACKGROUND: Disulfiram, an alcohol aversion agent, has been in use for >50 years. Numerous authors have reported an anticancer effect of this drug in vitro and in mouse models. More recently, several reports have claimed that disulfiram also possesses anti-stem cell activity. We set out to obtain initial data regarding the safety of combining this drug with chemotherapy and the possible effectiveness of disulfiram in a combination regimen in non-small cell lung cancer (NSCLC). METHODS: This phase II, multicenter, randomized, double-blinded study assessed the safety and efficacy of adding of disulfiram to cisplatin and vinorelbine for six cycles. Newly diagnosed NSCLC patients were recruited. Patients with either stage IV or what was considered at the time "wet IIIb" (since 2009, these patients have been considered stage IV) were recruited. The patients were treated with only chemotherapy, and none were treated with either surgery or chemoradiation. Disulfiram was administered at a dose of 40 mg three times daily. RESULTS: Forty patients were treated for more than two cycles, half with and half without disulfiram, which was well tolerated. An increase in survival was noted for the experimental group (10 vs. 7.1 months). Interestingly, there were only two long-term survivors, both in the disulfiram group. CONCLUSION: The addition of disulfiram to a combination regimen of cisplatin and vinorelbine was well tolerated and appeared to prolong survival in patients with newly diagnosed non-small cell lung cancer. The results from this small study seem encouraging enough for assessment in larger trials. Disulfiram is an inexpensive and safe drug; if its addition to chemotherapy could be shown to prolong survival, an effective regimen could be established and used widely, even in resource-poor countries.

Mitochondrial STAT3 plays a major role in IgE-antigen-mediated mast cell exocytosis.

BACKGROUND: The involvement of mitochondrial oxidative phosphorylation (OXPHOS) in mast cell exocytosis was recently suggested by the finding that mitochondria translocate to exocytosis sites upon mast cell activation. In parallel, mitochondrial signal transducer and activator of transcription 3 (STAT3) was found to be involved in ATP production. However, the regulation of mitochondrial STAT3 function and its connection to mast cell exocytosis is unknown. OBJECTIVE: We sought to explore the role played by mitochondrial STAT3 in mast cell exocytosis. METHODS: Experiments were performed in vitro with human and mouse mast cells and rat basophilic leukemia (RBL) cells and in vivo in mice. OXPHOS activity was measured after immunologic activation. The expression of STAT3, extracellular signal-regulated kinase 1/2, and protein inhibitor of activated STAT3 in the mitochondria during mast cell activation was determined, as was the effect of STAT3 inhibition on OXPHOS activity and mast cell function. RESULTS: Here we show that mitochondrial STAT3 is essential for immunologically mediated degranulation of human and mouse mast cells and RBL cells. Additionally, in IgE-antigen-activated RBL cells, mitochondrial STAT3 was phosphorylated on serine 727 in an extracellular signal-regulated kinase 1/2-dependent manner, which was followed by induction of OXPHOS activity. Furthermore, the endogenous inhibitor of STAT3, protein inhibitor of activated STAT3, was found to inhibit OXPHOS activity in the mitochondria, resulting in inhibition of mast cell degranulation. Moreover, mice injected with Stattic, a STAT3 inhibitor, had a significant decrease in histamine secretion. CONCLUSION: These results provide the first evidence of a regulatory role for mitochondrial STAT3 in mast cell functions, and therefore mitochondrial STAT3 could serve as a new target for the manipulation of allergic diseases.

Amino-acyl tRNA synthetases generate dinucleotide polyphosphates as second messengers: functional implications.

In this chapter we describe aminoacyl-tRNA synthetase (aaRS) production of dinucleotide polyphosphate in response to stimuli, their interaction with various signaling pathways, and the role of diadenosine tetraphosphate and diadenosine triphosphate as second messengers. The primary role of aaRS is to mediate aminoacylation of cognate tRNAs, thereby providing a central role for the decoding of genetic code during protein translation. However, recent studies suggest that during evolution, "moonlighting" or non-canonical roles were acquired through incorporation of additional domains, leading to regulation by aaRSs of a spectrum of important biological processes, including cell cycle control, tissue differentiation, cellular chemotaxis, and inflammation. In addition to aminoacylation of tRNA, most aaRSs can also produce dinucleotide polyphosphates in a variety of physiological conditions. The dinucleotide polyphosphates produced by aaRS are biologically active both extra- and intra-cellularly, and seem to function as important signaling molecules. Recent findings established the role of dinucleotide polyphosphates as second messengers.

EGFR mutation testing practice in advanced non-small cell lung cancer.

PURPOSE: Testing tumor samples for the presence of a mutation in the epithelial growth factor receptor (EGFR) gene is recommended for advanced non-squamous non-small cell lung cancer (NSCLC) patients. We aimed to collect data about common practice among Medical Oncologists treating lung cancer patients, regarding EGFR mutation testing in advanced NSCLC patients. METHODS: An internet-based survey was conducted among members of the Israeli Society for Clinical Oncology and Radiotherapy involved in the treatment of lung cancer patients. RESULTS: 24 Oncologists participated in the survey. The participants encompass the Oncologists treating most of the lung cancer patients in Israel. 79% of them use EGFR testing routinely for all advanced NSCLC patients. Opinions were split regarding the preferable biopsy site for EGFR testing material. 60% of participants recommend waiting for EGFR test results prior to initiation of first-line therapy. CONCLUSIONS: EGFR testing is requested in Israel routinely by most treating Oncologists for all advanced NSCLC patients, regardless of histology. In most cases, systemic treatment is deferred until the results of this test are received.

The functional role of Nudt2 in human triple negative breast cancer.

The main known function of Nudix hydrolase 2 (Nudt2) is to hydrolyze the secondary messenger diadenosine 5', 5'''-p1, p4-tetraphosphate (Ap4A). In this study we examined the role of Nudt2 in breast carcinoma through its expression in human invasive ductal carcinoma tissues, and its functions in human triple negative breast cancer (TNBC) cell lines. A significantly higher expression of Nudt2 was observed in human invasive ductal carcinoma tissues compared to that in normal breast tissue. Knockdown of Nudt2 in TNBC cell lines resulted in a significant reduction in cellular proliferation via the Ki67 marker, accompanied by G0/G1 phase cell cycle arrest, in the migration and invasion of these cells and in tumorigenicity and anchorage-independent growth. It can therefore be concluded that Nudt2 plays a significant role in promoting TNBC growth.

Outcomes of extracranial stereotactic body radiation therapy for induced oligometastatic non-small cell lung cancer on novel systemic therapy.

Background: Stereotactic body radiation therapy (SBRT) is often delivered in patients with oligometastatic disease (OMD). However, the specific subset of patients with polymetastatic non-small cell lung cancer (NSCLC) on novel systemic therapies who develop induced oligopersistant disease (OpersisD) or oligoprogressive disease (OprogD), as defined by the European Organisation for Research and Treatment of Cancer (EORTC) OMD classification, has not been well described. This study explores the outcomes of patients treated with this strategy. Methods: Patients with stage IV NSCLC being treated with osimertinib or immune checkpoint inhibitors (ICIs) who received extracranial SBRT for OpersisD or OprogD were identified in our retrospective analysis. Outcomes reported include progression-free survival (PFS), time to change of systemic treatment (TTCST), overall survival (OS), local control (LC) and treatment-related toxicity. Results: Forty-nine patients received SBRT for OpersisD (34.7%) or OprogD (65.3%) at a median of 5.8 and 15.3 months after start of systemic therapy, respectively. 55.1% received concurrent osimertinib and 44.9% received ICI. Seventy-seven extracranial lesions were treated with various fractionation schemas. At a median of 18.8 months follow-up from first SBRT, LC was achieved in 92.2% of total lesions treated (71). The 1-year OS was 91.7% for OpersisD and 83.3% for OprogD. OpersisD compared to OprogD had a longer median PFS (18.3 vs. 6.1 months) and longer median TTCST (23.6 vs. 13.5 months), median OS was not reached for either cohort. On multivariate analysis, patients treated with osimertinib had shorter PFS (HR: 2.20; 95% CI: 1.01-4.82; P=0.048) and shorter TTCST (HR: 2.83; 95% CI: 1.09-7.33; P=0.032). One patient (2%) experienced grade 3 pneumonitis after SBRT, and no grade 4-5 toxicities were reported with SBRT treatment. Conclusions: This study indicates that SBRT for OpersisD or OprogD in Stage IV NSCLC patients on osimertinib or ICIs is safe, very well tolerated, and may prolong the time before needing a shift in systemic therapy. Further prospective research is needed to validate and expand upon these findings.

Plasma Proteome-Based Test for First-Line Treatment Selection in Metastatic Non-Small Cell Lung Cancer.

PURPOSE: Current guidelines for the management of metastatic non-small cell lung cancer (NSCLC) without driver mutations recommend checkpoint immunotherapy with PD-1/PD-L1 inhibitors, either alone or in combination with chemotherapy. This approach fails to account for individual patient variability and host immune factors and often results in less-than-ideal outcomes. To address the limitations of the current guidelines, we developed and subsequently blindly validated a machine learning algorithm using pretreatment plasma proteomic profiles for personalized treatment decisions. PATIENTS AND METHODS: We conducted a multicenter observational trial (ClinicalTrials.gov identifier: NCT04056247) of patients undergoing PD-1/PD-L1 inhibitor-based therapy (n = 540) and an additional patient cohort receiving chemotherapy (n = 85) who consented to pretreatment plasma and clinical data collection. Plasma proteome profiling was performed using SomaScan Assay v4.1. RESULTS: Our test demonstrates a strong association between model output and clinical benefit (CB) from PD-1/PD-L1 inhibitor-based treatments, evidenced by high concordance between predicted and observed CB (R2 = 0.98, P < .001). The test categorizes patients as either PROphet-positive or PROphet-negative and further stratifies patient outcomes beyond PD-L1 expression levels. The test successfully differentiates between PROphet-negative patients exhibiting high tumor PD-L1 levels (≥50%) who have enhanced overall survival when treated with a combination of immunotherapy and chemotherapy compared with immunotherapy alone (hazard ratio [HR], 0.23 [95% CI, 0.1 to 0.51], P = .0003). By contrast, PROphet-positive patients show comparable outcomes when treated with immunotherapy alone or in combination with chemotherapy (HR, 0.78 [95% CI, 0.42 to 1.44], P = .424). CONCLUSION: Plasma proteome-based testing of individual patients, in combination with standard PD-L1 testing, distinguishes patient subsets with distinct differences in outcomes from PD-1/PD-L1 inhibitor-based therapies. These data suggest that this approach can improve the precision of first-line treatment for metastatic NSCLC.

Mast cell transcription factors--regulators of cell fate and phenotype.

Transcription factors have a key role in mast cell differentiation and response of differentiated mast cells to external stimuli. During differentiation of progenitor cells to mast cells, a role for different GATA transcription factors in combination with PU.1 expression and downregulation of C/EBPα has been described. Notch pathway has been proposed to have a role in mast cell development. The microphthalmia-associated transcription factor expression is upregulated in later stages of mast cells differentiation, but it is not expressed in the closely related basophiles. In differentiated mast cells, there is a role for transcription factors both in determining the specific mast cell phenotype and in the response to immune stimuli such as IgE-Ag. A large number of transcription factors, including AP-1 family proteins, microphthalmia-associated transcription factor and STAT5, are modulated by these stimuli. These transcription factors and related protein modulators form a complex transcription factor network. They can form stimuli regulated specific heterodimers and common inhibitors can move from one protein to another. Transcription factors are the key regulators of mast cell physiology. Modulation of key transcription by such means as the therapeutic siRNA may hopefully allow us to modulate mast cell function, obtaining clinical benefit in a variety of diseases. This article is part of a Special Issue entitled: Mast cells in inflammation.

Tumor STAT3 tyrosine phosphorylation status, as a predictor of benefit from adjuvant chemotherapy for breast cancer.

Signal transducer and activator of transcription 3 (STAT3) is a point of convergence for numerous oncogenic signaling pathways. In breast cancer cell lines and xenograft models activated STAT3 participates in breast tumorigenesis, while studies in humans have demonstrated that phosphorylated (tyrosine705)-STAT3 is a marker of good prognosis in breast cancer. In order to resolve this paradox we hypothesized that in clinic, phospho-STAT3 has a predictive role of benefit from adjuvant chemotherapy; therefore the goal of this study was to determine the usefulness of phospho-STAT3 status as a predictor of benefit from adjuvant chemotherapy in breast cancer patients. Immunohistochemical analysis of phospho-STAT3 was performed on a tissue microarray of breast cancer specimens. The expression pattern of phospho-STAT3 was retrospectively correlated with pathological parameters and overall survival in patients who were or were not treated with adjuvant chemotherapy. Of 375 tissue specimens interpretable for phospho-STAT3, 134 (36 %) exhibited positive phospho-STAT3 nuclear expression. Among 234 patients who received adjuvant therapy, those with tumors displaying positive phospho-STAT3 nuclear expression had a better ten-year rate of overall survival than patients with tumors displaying negative phospho-STAT3 nuclear expression (P = 0.001). Among patients who did not received adjuvant chemotherapy, positive phospho-STAT3 nuclear status was not correlated with increased overall survival (P = 0.54). Positive phospho-STAT3 was correlated with improved overall survival only among patients who received adjuvant chemotherapy in a multivariate analysis adjusted for stage, grade, hormonal status, Her2 status, and age, irrespective of the chemotherapy regimen received (hazard ratio for death, 0.35 [95 % CI 0.188-0.667]; P = 0.001). These findings support the role of phospho-STAT3 as a marker of favorable outcome in breast cancer patients treated with adjuvant chemotherapy. Whether phospho-STAT3 has a predictive role of benefit from adjuvant chemotherapy has to be validated on prospective, randomized, controlled studies.

The enigma of the role of protein inhibitor of activated STAT3 (PIAS3) in the immune response.

Protein inhibitor of activated STAT3 (PIAS3), the main cellular inhibitor of signal transducers and activator of transcription 3 (STAT3), has been described as a modulator of DNA binding transcription factors. The exploration of the emerging roles of PIAS3 in immune regulation is a growing and fascinating field. Recent discoveries have shed new light on the key role of PIAS3 in the regulation of transcriptional activity, and on the molecular mechanism involved. These findings suggest that the known functions of this signalling molecule are merely the "tip of the iceberg". This article reviews the challenging questions regarding the link between PIAS3 and the intracellular signalling in immune cells. Some of the known functions of PIAS3 that potentially modulate key proteins in the immune system will also be discussed.

Transcription factor E3, a major regulator of mast cell-mediated allergic response.

BACKGROUND: Microphthalmia transcription factor, an MiT transcription family member closely related to transcription factor E3 (TFE3), is essential for mast cell development and survival. TFE3 was previously reported to play a role in the functions of B and T cells; however, its role in mast cells has not yet been explored. OBJECTIVE: We sought to explore the role played by TFE3 in mast cell function. METHODS: Mast cell numbers were evaluated by using toluidine blue staining. FACS analysis was used to determine percentages of Kit and FcεRI double-positive cells in the peritoneum of wild-type (WT) and TFE3 knockout (TFE3(-/-)) mice. Cytokine and inflammatory mediator secretion were measured in immunologically activated cultured mast cells derived from either knockout or WT mice. In vivo plasma histamine levels were measured after immunologic triggering of these mice. RESULTS: No significant differences in mast cell numbers between WT and TFE3(-/-) mice were observed in the peritoneum, lung, and skin. However, TFE3(-/-) mice showed a marked decrease in the number of Kit(+) and FcεRI(+) peritoneal and cultured mast cells. Surface expression levels of FcεRI in TFE3(-/-) peritoneal mast cells was significantly lower than in control cells. Cultured mast cells derived from TFE3(-/-) mice showed a marked decrease in degranulation and mediator secretion. In vivo experiments showed that the level of plasma histamine in TFE3(-/-) mice after an allergic trigger was substantially less than that seen in WT mice. CONCLUSION: TFE3 is a novel regulator of mast cell functions and as such could emerge as a new target for the manipulation of allergic diseases.

Tumor PD-L1 expression and molecular profiling are not associated with immune checkpoint inhibitor-induced thyroid dysfunction in advanced NSCLC patients.

Background: Immune-checkpoint inhibitors (ICIs) have revolutionized the treatment of advanced non-small cell lung cancer (NSCLC), however are frequently associated with thyroid immune-related adverse events (IRAEs). We investigated the association between patient characteristics, tumor PD-L1 expression and molecular profile with the development of thyroid IRAEs in NSCLC patients. Methods: Single center, retrospective study including 107 NSCLC patients treated with PD-1/PD-L1 inhibitors from April 2016 to July 2020. All patients were euthyroid at baseline with at least two TSH measurements post-treatment initiation. The primary outcome was the difference in tumor PD-L1 expression in patients who developed any thyroid IRAEs versus those who remained euthyroid. Additional outcomes included development of overt thyroid dysfunction, the association of specific molecular alterations with thyroid IRAEs, and onset of thyroid IRAEs as a function of tumor PD-L1 expression. Results: Overall, 37 (34.6%) patients developed any thyroid dysfunction and 18 (16.8%) developed overt thyroid dysfunction. Tumor PD-L1 staining intensity was not associated with thyroid IRAEs. TP53 mutation was less likely to be associated with any thyroid dysfunction (p < 0.05) and no association was found between EGFR, ROS, ALK or KRAS mutations. There was no association between PD-L1 expression and time to develop thyroid IRAEs. Conclusion: PD-L1 expression is not associated with the development of thyroid dysfunction in advanced NSCLC patients treated with ICIs, suggesting that thyroid IRAEs are unrelated to tumor PD-L1 expression.