JAK3/STAT5/6 pathway alterations are associated with immune deviation in CD8 T cells in renal cell carcinoma patients

T cells in health and disease

T cells are crucial for immune functions to maintain health and prevent disease. T cell development occurs in a stepwise process in the thymus and mainly generates CD4⁺ and CD8⁺ T cell subsets. Upon antigen stimulation, naïve T cells differentiate into CD4⁺ helper and CD8⁺ cytotoxic effector and memory cells, mediating direct killing, diverse immune regulatory function, and long-term protection. In response to acute and chronic infections and tumors, T cells adopt distinct differentiation trajectories and develop into a range of heterogeneous populations with various phenotype, differentiation potential, and functionality under precise and elaborate regulations of transcriptional and epigenetic programs. Abnormal T-cell immunity can initiate and promote the pathogenesis of autoimmune diseases. In this review, we summarize the current understanding of T cell development, CD4⁺ and CD8⁺ T cell classification, and differentiation in physiological settings. We further elaborate the heterogeneity, differentiation, functionality, and regulation network of CD4⁺ and CD8⁺ T cells in infectious disease, chronic infection and tumor, and autoimmune disease, highlighting the exhausted CD8⁺ T cell differentiation trajectory, CD4⁺ T cell helper function, T cell contributions to immunotherapy and autoimmune pathogenesis. We also discuss the development and function of γδ T cells in tissue surveillance, infection, and tumor immunity. Finally, we summarized current T-cell-based immunotherapies in both cancer and autoimmune diseases, with an emphasis on their clinical applications. A better understanding of T cell immunity provides insight into developing novel prophylactic and therapeutic strategies in human diseases.

Nonsense-Mediated Decay Targeted RNA (ntRNA): Proposal of a ntRNA–miRNA–lncRNA Triple Regulatory Network Usable as Biomarker of Prognostic Risk in Patients with Kidney Cancer

The most prevalent subtype of renal cell carcinoma (RCC), kidney renal clear cell carcinoma (KIRC) may be associated with a poor prognosis in a high number of cases, with a stage-specific prognostic stratification currently in use. No reliable biomarkers have been utilized so far in clinical practice despite the efforts in biomarker research in the last years. Nonsense-mediated mRNA decay (NMD) is a critical safeguard against erroneous transcripts, particularly mRNA transcripts containing premature termination codons (called nonsense-mediated decay targeted RNA, ntRNA). In this study, we first characterized 296 differentially expressed ntRNAs that were independent of the corresponding gene, 261 differentially expressed miRNAs, and 4653 differentially expressed lncRNAs. Then, we constructed a hub ntRNA–miRNA–lncRNA triple regulatory network associated with the prognosis of KIRC. Moreover, the results of immune infiltration analysis indicated that this network may influence the changes of the tumor immune microenvironment. A prognostic model derived from the genes and immune cells associated with the network was developed to distinguish between high- and low-risk patients, which was a better prognostic than other models, constructed using different biomarkers. Additionally, correlation of methylation and ntRNAs in the network suggested that some ntRNAs were regulated by methylation, which is helpful to further study the causes of abnormal expression of ntRNAs. In conclusion, this study highlighted the possible clinical implications of ntRNA functions in KIRC, proposing potential significant biomarkers that could be utilized to define the prognosis and design personalized treatment plans in kidney cancer management in the next future.

Morphine in Combination with Ketamine Improves Cervical Cancer Pain and Suppresses Immune Function via the JAK3/STAT5 Pathway

Background

The role of ketamine as an adjuvant for morphine in the treatment of cancer pain and immune functions has been confirmed. This study aimed to explore the role of morphine and ketamine on cancer pain and T cells of patients with cervical cancer (CC).

Methods

T cells were isolated from peripheral blood mononuclear cells (PBMC) of CC patients by positive selection using anti-CD3 beads. The isolated T cells were assigned into three groups: the control group, the morphine group, and the morphine + ketamine (Mor + Ket) group. The percentages of CD4⁺ and CD8⁺ were analyzed by flow cytometry. The levels of interferon (IFN)-γ, interleukin (IL)-2, and IL-17 and the corresponding mRNA expression in vitro were determined using ELISA and qRT-PCR, respectively. Western blotting was used for detection of JAK3/STAT5 pathway-related proteins after naltrexone treatment in vitro. Afterwards, all the patients were further divided into the morphine group and the Mor + Ket group in accordance with the principles of the randomized and double-blind method to assess pain intensity.

Results

Our in vivo results showed that drug combinations relieved cancer pain more effectively than morphine intervention. The in vitro results demonstrated that the combination of morphine and ketamine may decrease CD4⁺ percentage, CD4⁺/CD8⁺ ratio, and the levels of IFN-γ, IL-2, and IL-17 via the JAK3/STAT5 pathway.

Conclusions

Our finding indicated that morphine-ketamine combination could improve cancer pain and repress immune function via the JAK3/STAT5 pathway in the progression of CC.

ACE2 Is a Prognostic Biomarker and Associated with Immune Infiltration in Kidney Renal Clear Cell Carcinoma: Implication for COVID-19

Background

KIRC is one of the most common cancers with a poor prognosis. ACE2 was involved in tumor angiogenesis and progression in many malignancies. The role of ACE2 in KIRC is still ambiguous.

Methods

Various bioinformatics analysis tools were investigated to evaluate the prognostic value of ACE2 and its association with immune infiltration in KIRC.

Results

ACE2 was shown to be downregulated in KIRC at the mRNA and protein level. Low expression of ACE2 protein in KIRC patients was observed in subgroup analyses based on gender, age, weight, tumor grade, and cancer stage. Upregulation of ACE2 in KIRC was associated with a favorable prognosis. ACE2 mRNA expression showed a positive correlation with the abundance of immune cells (B cells, CD8+ T cells, macrophages, neutrophils, and dendritic cells) and the level of immune markers of different immune cells in KIRC. ACE2 expression could affect, in part, the immune infiltration and the advanced cancer stage. Moreover, enrichment analysis revealed that ACE2 in KIRC were mainly involved in translation factor activity, immunoglobulin binding, metabolic pathways, transcriptional misregulation in cancerous cells, cell cycle, and ribosomal activity. Several ACE2-associated kinases, miRNA, and transcription factor targets in KIRC were also identified.

Conclusion

ACE2 was downregulated in KIRC and served as a prognostic biomarker. It was also shown to be associated with immune infiltration.

Characterization of Cytotoxic T Lymphocytes (CTL) by Tissue Microarray

Tissue microarray (TMA) is a smart technical innovation recently imposed in pathology research. This technology provides a high-throughput analysis of multiple tissues at the same time. The technique allows faster analysis and considerably reducing costs for the staining because many small representative tissue samples from hundreds of different cases are assembled on a single histologic slide. This versatile technique may improve conventional microscopic techniques to detect and characterize cytotoxic T lymphocytes (CTL). Immunohistochemistry (IHC) may be effectively employed in CTL characterization to identify the location and distribution of target antigens in tissues by staining with a specific antibody. The antibody may be conjugated to either a fluorescent or enzymatic label, and the location of the label seen through a microscope approximates the position of the target antigen.This article summarizes the technical aspects of tissue microarray construction and sectioning, advantages, application, and limitations associated with immunohistochemistry and immunofluorescence.

Prediction of ISUP grading of clear cell renal cell carcinoma using support vector machine model based on CT images

BACKGROUND

To explore whether radiomics combined with computed tomography (CT) images can be used to establish a model for differentiating high grade (International Society of Urological Pathology [ISUP] grade III-IV) from low-grade (ISUP I-II) clear cell renal cell carcinoma (ccRCC).

METHODS

For this retrospective study, 3-phase contrast-enhanced CT images were collected from 227 patients with pathologically confirmed ISUP-grade ccRCC (155 cases in the low-grade group and 72 cases in the high-grade group). First, we delineated the largest dimension of the tumor in the corticomedullary and nephrographic CT images to obtain the region of interest. Second, variance selection, single variable selection, and the least absolute shrinkage and selection operator were used to select features in the corticomedullary phase, nephrographic phase, and 2-phase union samples, respectively. Finally, a model was constructed using the optimal features, and the receiver operating characteristic curve and area under the curve (AUC) were used to evaluate the predictive performance of the features in the training and validation queues. A Z test was employed to compare the differences in AUC values.

RESULTS

The support vector machine (SVM) model constructed using the screening features for the 2-stage joint samples can effectively distinguish between high- and low-grade ccRCC, and obtained the highest prediction accuracy. Its AUC values in the training queue and the validation queue were 0.88 and 0.91, respectively. The results of the Z test showed that the differences between the 3 groups were not statistically significant.

CONCLUSION

The SVM model constructed by CT-based radiomic features can effectively identify the ISUP grades of ccRCC.

Efficacy of sorafenib adjuvant therapy in northwestern Chinese patients with non-metastatic renal-cell carcinoma after nephrectomy: A multicenter retrospective study

Recent studies have confirmed the efficacy of sorafenib for patients with advanced renal cell carcinoma; however, its efficacy and safety as an adjuvant therapy in patients with non-metastatic and loco-regional renal cell carcinoma after surgery remains controversial. Thus, the aim of the present retrospective study was to evaluate the efficacy of adjuvant sorafenib therapy in such patients from 8 centers in northwestern China that were treated from August 2009 to December 2016.After surgery, the patients (n = 48) received oral sorafenib for 3 months. The control group (n = 48) comprised patients that underwent the same surgery from December 2009 to June 2016 but without adjuvant therapy who were matched 1:1 with the sorafenib group with respect to sex, age, pathological findings, disease stage and grade, operation time, and surgical procedure. The primary outcome compared between the groups was disease-free survival. Adverse events were also recorded to evaluate the safety of sorafenib. The influence of patients' characteristics and laboratory tests on recurrence was analyzed using unconditional logistic regression.Overall, the demographic characteristics of the 2 groups were similar. There was no significant difference in the rate of recurrence (8.3% for sorafenib patients and 6.2% for the matched patients, P = .66) or median disease-free survival between the 2 groups (hazard ratio = 1.561, 95% confidence interval = 0.349-6.987, P = .56). In multiple logistic regression analysis, increased blood urea nitrogen (BUN) emerged as an independent predictor of recurrence risk (P = .02).These results indicate that postoperative sorafenib adjuvant therapy did not achieve the expected beneficial effect, pointing to the need for further studies to evaluate its utility in such cases.

Predictive value of preoperative monocyte-lymphocyte ratio among patients with localized clear renal cell carcinoma of ≤7 cm on preoperative imaging

We investigated the prognostic ability of preoperative monocyte-lymphocyte ratio for oncologic outcomes in non-metastatic clear cell renal cell carcinoma of ≤7 cm on preoperative computed tomography (CT).We retrospectively reviewed 1637 patients who underwent radical or partial nephrectomy for solid renal masses ≤7 cm (2005-2014). We included 1137 patients after exclusion of benign pathology, non-clear cell, morbidity affecting inflammatory markers, metastasis, regional lymphadenopathy, positive margin, and follow up <12 months. According to cutoff values of 0.21, we had high ≥0.21 and low <0.21 preoperative monocyte-lymphocyte ratio groups. Mann-Whitney U and chi-squared tests were used for continuous and Dichotomous variables. Univariate and multivariate Cox regression analysis were used to predict factors affecting recurrence and survival. Kaplan-Meier curve was used for survival analysis.At a median age of 56 years with a median follow up of 65 months, 51 patients had a recurrence (4.5%). There were no statistical differences between the high and low monocyte-lymphocyte ratio groups as regard the pathological characters (P > .005). Monocyte-lymphocyte ratio was a predictor for recurrence-free and cancer-specific survivals (hazard risk [HR] 2.17, P = .012 and HR 4.06, P = .004, respectively). A higher monocyte-lymphocyte ratio was significantly associated with worse, both 10-year recurrence-free (90.2% vs 94.9%) and cancer-specific survival (89.5% vs 98.8%) (Log-rank, P = .002 and P < .001, respectively).The preoperative monocyte-lymphocyte ratio is an independent prognostic marker for recurrence-free and cancer-specific survivals after curative surgery for non-metastatic clear cell renal cell carcinoma of ≤7 cm on preoperative CT.

Effects of Di-(2-ethylhexyl) Phthalate on Lipid Metabolism by the JAK/STAT Pathway in Rats

The most widely used plasticizer, di-(2-ethylhexyl) phthalate (DEHP), is known to affect lipid metabolism and adipogenesis. We studied the effects of dietary DEHP exposure on metabolism in rats as well as the role of the JAK/STAT pathway in this process. Eighty rats were exposed to DEHP (0, 5, 50 and 500 mg/kg/d) through dietary intake for 4 weeks. We then collected blood samples, liver, and adipose tissues to detect modifications in the levels of serum lipids, leptin, adiponectin and insulin. JAK3, STAT5a and PPARγ expression were detected at both the gene and protein levels. The activation of JAK3 and STAT5a was also detected. The DEHP-exposed rats had increased body weight, serum lipid, insulin, and leptin levels. Moreover, the JAK3/STAT5a pathway was activated in the adipose tissue; however, this pathway was not activated in the liver. The mRNA of SREBP-1c in the liver was increased significantly among each of the groups, in contrast to the levels found in the mature SREBP-1c protein form. Furthermore, the expression of FABP4, Acox and FASn was decreased in the liver, but increased in adipose tissue. Thus, we conclude that exposure to DEHP reduces the hydrolysis of lipid and promotes triglyceride accumulation by oppositely regulating the activation state of JAK/STAT pathway in the liver and adipose tissue, resulting in the disorder of body lipid metabolism and obesity.

miR-29b and miR-198 overexpression in CD8+ T cells of renal cell carcinoma patients down-modulates JAK3 and MCL-1 leading to immune dysfunction

Background

Mammalian microRNAs (miR) regulate the expression of genes relevant for the development of adaptive and innate immunity against cancer. Since T cell dysfunction has previously been reported in patients with renal cell carcinoma (RCC; clear cell type), we aimed to analyze these immune cells for genetic and protein differences when compared to normal donor T cells freshly after isolation and 35 days after in vitro stimulation (IVS) with HLA-matched RCC tumor cells.

Methods

We investigated gene expression profiles of tumor-reactive CD8⁺ T cells obtained from RCC patient and compared with their HLA-matched healthy sibling donors using a microarray approach. In addition, miRNAs analysis was performed in a validation cohort of peripheral blood CD8⁺ T cells from 25 RCC patients compared to 15 healthy volunteers.

Results

We observed that CD8⁺ T cells from RCC patients expressed reduced levels of anti-apoptotic and proliferation-associated gene products when compared with normal donor T cells both pre- and post-IVS. In particular, JAK3 and MCL-1 were down-regulated in patient CD8⁺ T cells versus their normal counterparts, likely due to defective suppressor activity of miR-29b and miR-198 in RCC CD8⁺ T cells. Indeed, specific inhibition of miR-29b or miR-198 in peripheral blood mononuclear cells (PBMCs) isolated from RCC patients, resulted in the up-regulation of JAK3 and MCL-1 proteins and significant improvement of cell survival in vitro.

Conclusions

Our results suggest that miR-29b and miR-198 dysregulation in RCC patient CD8⁺ T cells is associated with dysfunctional immunity and foreshadow the development of miR-targeted therapeutics to correct such T cell defects in vivo.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-016-0841-9) contains supplementary material, which is available to authorized users.

Tumor infiltrating CD8+ T lymphocyte count is independent of tumor TLR9 status in treatment naïve triple negative breast cancer and renal cell carcinoma

Toll-like receptor 9 (TLR9) is a cellular DNA-receptor of the innate immune system that is widely expressed in cancers. We demonstrated that low tumor TLR9 expression predicts poor disease-specific survival in triple negative breast cancer (TNBC) and renal cell carcinoma (RCC). We hypothesized that this is because TLR9 expression affects tumor immunophenotype. To begin to test this, we compared the number of tumor infiltrating CD8⁺ T lymphocytes with TLR9 expression in treatment naïve breast cancer (n = 197) and RCC (n = 94) cohorts with known TLR9 expression status. CD8⁺ T lymphocyte counts were assayed with image analysis after immunohistochemistry (IHC). Tumor TLR9 expression was not correlated with CD8⁺ T cell counts in breast cancer or RCC. CD8⁺ T cell counts were significantly associated with tumor proliferation index in TNBC, but not in non-TNBC. CD8⁺ T cell counts were also significantly associated with tumor grade in non-TNBC, but not in TNBC. In RCC, CD8⁺ T cell counts were significantly associated with tumor stage. CD8⁺ T cell counts were significantly associated with prognosis in TNBC and RCC, but the presence of CD8⁺ T cells in these tumors had opposite effects on disease-specific survival: High CD8⁺ counts were associated with better prognosis in TNBC and worse prognosis in RCC. Among TNBC patients, those with low tumor TLR9 and low CD8⁺ T cell counts had the poorest prognosis (log-rank p = 0.0002 vs. high tumor TLR9 and high CD8⁺ T cell count). In conclusion, pre-treatment tumor TLR9 status is not associated with tumor infiltrating CD8⁺ T lymphocytes in TNBC or RCC. The combination of TLR9 and CD8⁺ TIL count might be a novel composite prognostic marker in TNBC.

Targeting the JAK/STAT pathway in cytotoxic T lymphocytes (CTL) by Next Generation Sequencing (NGS)

Next Generation Sequencing (NGS), together with our evolving knowledge of genes and disease, is likely to change the current practice of medicine and public health by facilitating more accurate, sophisticated, and cost-effective genetic testing. Here, we propose a new molecular approach by using MiSeq Sequencing System (Illumina) to investigate the presence of mutations/variants in genes of JAK/STAT pathway involved in different cytotoxic T lymphocytes (CTL)-mediated immune disorders and to develop and validate new and less expensive molecular protocol based on Next Generation Sequencing.

Characterization of CTL by microscopy

Conventional microscopic techniques may be easily employed to detect and characterize cytotoxic T lymphocytes (CTL). Immunohistochemistry (IHC) may be effectively performed in CTL characterization to identify the location and distribution of target antigens in suspension cells or in tissues by staining with a specific antibody. The antibody may be conjugated to either a fluorescent or an enzymatic label, and the location of the label seen through a microscope approximates the position of the target antigen. Here, immunohistochemistry and immunofluorescence for both paraffin-embedded and frozen tissues and for suspended cell are described. Moreover, specific recommendations for analysis of suspension of cells are provided.

Negative and positive separation techniques for the isolation of antigen-specific CD8(+) T cells from blood and tumor tissue

Adoptive transfer of tumor-reactive cytotoxic T cells (CTLs) is a promising therapeutic approach for the treatment of solid tumors. To develop these strategies, it is necessary to isolate specific leukocyte subpopulations from peripheral blood or tumor tissue (referred to as tumor-infiltrating lymphocytes (TIL)) that will be reinfused into the patient after expansion in vitro. The ideal cell isolation approach should be performed rapidly, thereby maximizing the recovery and viability of the purified cells. Here, we describe the negative or the positive separation procedures to isolate CD8(+) T cells from whole blood, from peripheral blood mononuclear cells (PBMCs), or from cancer tissue. Purified CD8(+) cells will be used for different downstream applications such as protein and gene expression profile analysis in order to assess their intrinsic cytotoxic ability.

TIPE2 mRNA overexpression correlates with TNM staging in renal cell carcinoma tissues

Tumor necrosis factor α-induced protein-8 like-2 (TIPE2) is a gene that maintains immune homeostasis. The aim of the present study was to determine whether TIPE2 is associated with renal cell carcinoma (RCC) progression. The mRNA expression levels of TIPE2 and myxoma resistance protein 1 (MX1; a type I interferon-inducible gene) were investigated in renal cancer tissues. A total of 46 patients who fulfilled the RCC criteria of the World Health Organization (WHO; revised in 2004) and 39 control patients with renal contusions requiring surgical extraction were enrolled. Tumor and normal renal tissues were sampled from all subjects through surgery. Total RNA was extracted and the expression of the TIPE2 and MX1 genes was evaluated by quantitative polymerase chain reaction (qPCR) analysis. TIPE2 mRNA expression was significantly upregulated in the RCC patients compared with the controls (P=0.001), while MX1 mRNA expression was decreased in the RCC patients compared with the controls (P=0.0001). Furthermore, the TIPE2 mRNA expression levels were positively correlated with TNM staging (r=0.803, P=0.001) and showed a negative correlation with the MX1 mRNA expression levels (r=−0.763, P=0.001) in the RCC patients. These results indicate that the increased expression of the TIPE2 gene is markedly associated with RCC and suggests an important role for the TIPE2 gene in the pathogenesis of RCC.

Intrinsic immune alterations in renal cell carcinoma and emerging immunotherapeutic approaches

INTRODUCTION

Individuals affected by kidney cancer present a variety of immune abnormalities including cellular immune dysfunction, cytokine alterations and antigen presentation defects. On the other hand, spontaneous remissions are seen in up to 4% of renal cell carcinoma (RCC) patients and they are thought to occur via immune mechanisms.

AREAS COVERED

The authors comprehensively review the immune abnormalities in RCC patient and describe the kidney cancer immunotherapy candidates that are most advanced in their clinical development. Most relevant publications were identified through searching the PubMed database; the obtained information was thoroughly analyzed and synthesized.

EXPERT OPINION

As cure in advanced RCC cannot be accomplished with the current therapy standards such as tyrosine kinase inhibitors and mammalian target of rapamycin inhibitors, new treatment strategies are being sought. Enhancing the immune system represents an appealing avenue for kidney cancer therapy. Disappointingly, high-dose interleukin-2 and interferon-α cause severe toxicity and produce a questionable clinical benefit. The authors postulate that the 'durable responses' seen with these agents in only a handful of RCC patients represent spontaneous remissions. Promising immune strategies in RCC such as anti-cytotoxic T-lymphocyte-associated protein antibodies, anti-programmed cell death 1 (PD1)/PD1 ligand and tumor vaccines may expand the existing options for kidney cancer in future years.

Balance of CD8+ CD28+ / CD8+ CD28- T lymphocytes is vital for patients with ulcerative colitis

BACKGROUND

Immune balances are important for many diseases including ulcerative colitis (UC). This study aimed to explore the role of the balance between CD8+ CD28+ and CD8+ CD28- T lymphocytes for the immunological pathogenesis of UC.

METHODS

Sixteen patients with UC, 16 patients with irritable bowel syndrome (IBS) and 15 healthy volunteers were enrolled. The frequencies of CD8+ CD28+ and CD8+CD28- T lymphocytes in peripheral blood and colon tissue were tested using flow cytometry and immunofluorescent, respectively. The cytokines of the two lymphocytes were detected by protein chips and ELISA. The expression of the signal transducers, the JAK3 and STAT6, as well the transcription factors, the NFATc2 and GATA3, was all detected by both western blot and immunohistochemistry.

RESULTS

For UC patients, the frequencies of CD8+ CD28+ T lymphocytes, together with the ratios of CD8+ CD28+ / CD8+ CD28- T lymphocytes in blood and colon tissue, were significantly lower than those in both IBS patients and healthy volunteers. But the frequencies of CD8+ CD28- T lymphocytes in blood and colon tissue of the UC patients were significantly higher than the other two groups. The concentration of IL-7 and -13, and the expression of JAK3 and STAT6 in UC patients, were significantly lower when compared with the other two groups. Conversely, the concentration of IL-12p40 and -15, and the expression of GATA3 and NFATc2 in UC patients, were significantly higher than both IBS and control group.

CONCLUSIONS

The balance of CD8+ CD28+ / CD8+ CD28- T lymphocytes plays a vital role in UC, while the balance tilt towards CD8+ CD28+ T lymphocytes is beneficial for patients with UC.

Signal transducer and activator of transcription-5 mediates neuronal apoptosis induced by inhibition of Rac GTPase activity

In several neuronal cell types, the small GTPase Rac is essential for survival. We have shown previously that the Rho family GTPase inhibitor Clostridium difficile toxin B (ToxB) induces apoptosis in primary rat cerebellar granule neurons (CGNs) principally via inhibition of Rac GTPase function. In the present study, incubation with ToxB activated a proapoptotic Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway, and a pan-JAK inhibitor protected CGNs from Rac inhibition. STAT1 expression was induced by ToxB; however, CGNs from STAT1 knock-out mice succumbed to ToxB-induced apoptosis as readily as wild-type CGNs. STAT3 displayed enhanced tyrosine phosphorylation following treatment with ToxB, and a reputed inhibitor of STAT3, cucurbitacin (JSI-124), reduced CGN apoptosis. Unexpectedly, JSI-124 failed to block STAT3 phosphorylation, and CGNs were not protected from ToxB by other known STAT3 inhibitors. In contrast, STAT5A tyrosine phosphorylation induced by ToxB was suppressed by JSI-124. In addition, roscovitine similarly inhibited STAT5A phosphorylation and protected CGNs from ToxB-induced apoptosis. Consistent with these results, adenoviral infection with a dominant negative STAT5 mutant, but not wild-type STAT5, significantly decreased ToxB-induced apoptosis of CGNs. Finally, chromatin immunoprecipitation with a STAT5 antibody revealed increased STAT5 binding to the promoter region of prosurvival Bcl-xL. STAT5 was recruited to the Bcl-xL promoter region in a ToxB-dependent manner, and this DNA binding preceded Bcl-xL down-regulation, suggesting transcriptional repression. These data indicate that a novel JAK/STAT5 proapoptotic pathway significantly contributes to neuronal apoptosis induced by the inhibition of Rac GTPase.

JAK3 in clear cell renal cell carcinoma: mutational screening and clinical implications

OBJECTIVES

Janus Kinase 3 (JAK3) mediates cytokine signaling and T-cell activation. We hypothesized that JAK3 mutations may contribute to the development and progression of clear cell renal cell carcinoma (ccRCC). To test this hypothesis, we performed mutational screening and functional studies.

PATIENTS AND METHODS

This hospital-based case-control study included 50 patients with ccRCC and 100 age- and gender-matched controls. Both genomic and tumor DNA were extracted. All 23 JAK3 exons were amplified by PCR and analyzed by denaturing high-performance liquid chromatography and automatic sequencing. Effects of JAK3 mutations on interleukin-2-stimulated peripheral T-cells were analyzed by confocal laser-scanning microscopy and immunoprecipitation.

RESULTS

Four different JAK3 germline missense mutations (p.Gln13Lys; p.Arg925Ser; p.Ala677Thr, p.Val722Ile) were found in a total of 7 ccRCC patients (14%), but in none of the controls (P = 0.0006). All germline mutations were similarly detected in the tumors. An additional somatic missense mutation (p.Tyr238Cys) was found in a patient who had a germline mutation. Four of the mutations have not been previously described (p.Gln13Lys; p.Arg925Ser; p.Ala677Thr, p.Tyr238Cys). Patients with JAK3 mutations more frequently presented with metastases (3 out of 4 [75%] vs. 4 out of 46 [9%]; P = 0.004) and had poorer survival (P = 0.049). In p.Arg925Ser and p.Ala677Thr/p.Val722Ile, functional analyses showed abnormal JAK3 and STAT5 tyrosine phosphorylation and a reduction of JAK3/STAT5 interaction.

CONCLUSIONS

JAK3 mutations are found in a subset of ccRCC patients and may be associated with ccRCC development and a greater risk of metastases. JAK3 function is compromised in p.Arg925Ser and p.Ala677Thr/p.Val722Ile. Future studies with a larger number of patients need to confirm these findings.