Inhibiting WEE1 and IKK-RELA Crosstalk Overcomes TNFα Resistance in Head and Neck Cancers

TNFα is a key mediator of immune and radiotherapy-induced cytotoxicity, but many cancers, including head and neck squamous cell carcinomas (HNSCC), display TNF resistance due to activation of the canonical IKK-NF-κB/RELA pro-survival pathway. However, toxicities associated with direct targeting of the canonical pathway point to the need to identify mechanism(s) contributing to TNFα resistance and synthetic lethal targets to overcome such resistance in cancer cells. Here, RNAi screening for modulators of TNFα-NF-κB reporter activity and cell survival unexpectedly implicated the WEE1 and CDC2 G2-M checkpoint kinases. The IKKα/β-RELA and WEE1-CDC2 signaling pathways are activated by TNFα and form a complex in cell lines derived from both human papillomavirus (-) and (+) subtypes of HNSCC. WEE1 inhibitor AZD1775 reduced IKK/RELA phosphorylation and the expression of NF-κB-dependent pro-survival proteins Cyclin D1 and BCL2. Combination of TNFα and AZD1775 enhanced caspase-mediated apoptosis in vitro, and combination treatment with radiotherapy and AZD1775 potentiated inhibition of HNSCC tumor xenograft growth in vivo, which could be significantly attenuated by TNFα depletion. These data offer new insight into the interplay between NF-κB signaling and WEE1-mediated regulation of the G2-M cell-cycle checkpoint in HNSCC.

IMPLICATIONS

Inhibiting WEE1 and IKK-RELA crosstalk could potentially enhance the effects of therapies mediated by TNFα with less systemic immune suppression and toxicity than observed with direct interruption of IKK-NF-κB/RELA signaling.

Death agonist antibody against TRAILR2/DR5/TNFRSF10B enhances birinapant anti-tumor activity in HPV-positive head and neck squamous cell carcinomas

Head and neck squamous cell carcinomas (HNSCC) induced by human papillomavirus (HPV) have increased recently in the US. However, the distinct alterations of molecules involved in the death pathways and drug effects targeting inhibitor of apoptosis proteins (IAPs) have not been extensively characterized in HPV(+) HNSCC cells. In this study, we observed the distinct genomic and expression alterations of nine genes involved in cell death in 55% HNSCC tissues, which were associated with HPV status, tumor staging, and anatomic locations. Expression of four genes was statistically correlated with copy number variation. A panel of HPV(+) HNSCC lines showed abundant TRAILR2 and IAP1 protein expression, but were not sensitive to IAP inhibitor birinapant alone, while combinatory treatment with TNFα or especially TRAIL enhanced this drug sensitivity. The death agonistic TRAILR2 antibody alone showed no cell inhibitory effects, whereas its combination with birinapant and/or TRAIL protein demonstrated additive or synergistic effects. We observed predominantly late apoptosis mode of cell death after combinatorial treatments, and pan-caspase (ZVAD) and caspase-8 (ZIETD) inhibitors attenuated treatment-induced cell death. Our genomic and expression data-driven study provides a framework for identifying relevant combinatorial therapies targeting death pathways in HPV(+) HNSCC and other squamous cancer types.

Abstract 6042: TNFa co-activates IKK/NF-kB/RELA prosurvival and WEE1-CDC2 G2/M checkpoint signaling and is targetable by WEE1 antagonist AZD1775 in head and neck cancer

Cytotoxic and genotoxic therapies are known to induce the prosurvival Inhibitor-kappaB kinase (IKK)-NF-κB/RELA pathway and DNA repair at the G2/M checkpoint, thereby promoting therapeutic resistance, but the coordination of these mechanisms is unclear. Our recent RNAi screen unexpectedly uncovered possible crosstalk between WEE1, a G2/M checkpoint kinase and the TNFα-IKK-NF-κB prosurvival pathway components. siRNAs targeting WEE1 and IKKs both inhibited TNFα-inducible NF-κB activity in a HNSCC reporter line, suggesting a mechanistic linkage. We investigated this potential connection further and studied the effect of WEE1 inhibition using AZD1775 in head and neck squamous cell carcinoma (HNSCC) cells and mouse xenograft models. Increased expression, phosphorylation and cellular localization of IKK-NF-κB and WEE1-CDC2 axis proteins co-occurred in a subset of HNSCC lines, and were inversely co-modulated by TNFα and WEE1 kinase inhibitor AZD1775. WEE1 co-immunoprecipitated with the IKKα/β and RELA protein complex, and AZD1775 or an IKK inhibitor, IKK16, inhibited phosphorylation and kinase activities, further suggesting that these two axes interact with each other. AZD1775 sensitized HNSCC cells to TNFα-induced cytotoxicity, in part by inhibiting IKK-dependent phosphorylation and nuclear localization of NF-κB activation, and expression of target prosurvival protein BCL-2. Combination of AZD1775 with radiation, a known inducer of TNFα- and DNA-mediated cytotoxicity, potently inhibited HPV+/- HNSCC tumor xenografts. Depleting TNFα abolished the anti-tumor activity of combined therapy with AZD1775 and radiation. The findings of our study reveal that TNFα co-modulates a novel interaction between the prosurvival IKK/NF-κB/RELA and WEE1-CDC2 G2/M checkpoint pathway and that components of both the pathways are inhibited by AZD1775. Our mouse xenograft experiments suggest that AZD1775, when combined with radiation, significantly delays the growth of xenograft HNSCC tumors differing in HPV status in a TNFα-dependent manner. The current findings reveal a novel mechanism whereby crosstalk and co-activation of WEE1- and NF-κB-signaling promotes resistance to TNFα-mediated cytotoxicity, which may be targeted using WEE1 inhibitors.

Supported by NIDCD projects ZIA-DC-000016, -73 and 74.

Citation Format: Ramya Viswanathan, Zhengbo Hu, Jianghong Chen, Xinping Yang, Angel Huynh, Paul Clavijo, Yi An, Yvette Robbins, Christopher Silvin, Clint Allen, Anthony Saleh, Zhong Chen, Carter Van Waes. TNFa co-activates IKK/NF-kB/RELA prosurvival and WEE1-CDC2 G2/M checkpoint signaling and is targetable by WEE1 antagonist AZD1775 in head and neck cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6042.

Abstract 5175: Birinapant enhances death agonist antibody against TRAILR2 anti-tumor activity in HPV-positive head and neck squamous cell carcinomas

Human papilloma virus positive (HPV+) head and neck squamous cell carcinomas (HNSCC) exhibit a better prognosis and response to therapies than HPV(-) cancers. Analysis of HNSCC TCGA dataset provides evidence for distinct alterations in expression of components of the NF-κB and cell death pathways in HPV(+/-) HNSCC. Previously, we have found that birinapant, a novel SMAC mimetic that inhibits inhibitor of apoptosis proteins (IAPs), sensitizes a subset of HPV(-) HNSCC cell lines to death agonists like TNF-α and TRAIL. In our current study, we have observed that birinapant also sensitizes several HPV(+) cell lines to TNF-α and TRAIL in vitro. The IC50 for birinapant was under 50nM with TRAIL and TNF-α for the HPV (+) UPCI-SCC-90 and UM-SCC-47 cell lines. As TRAIL is known as a selective cancer cell death inducer, we explored its potential for enhancing death signaling in HPV(+) HNSCC cells via the effects of an agonistic polyclonal TRAILR2 antibody. Flow cytometry analysis confirmed the presence of TRAILR2 expression on the cell surface of the two HPV(+) cell lines. Treatment of cells with the antibody or TRAIL alone showed little or no inhibitory effect on growth of either cell lines. However, treatment with birinapant plus antibody, and especially the triple combination of birinapant, TRAIL, and antibody showed additive or synergistic effects to inhibit cell proliferation in a dose dependent manner. The Fixed Apoptotic Necrotic test using anti-phosphatidylserine and Zombie fixable dye showed that late apoptosis was the predominant mode of cell death for all combination groups for both cell lines at 48 hours post treatment. The proportion of cells undergoing apoptosis/necrosis was highest in the triple combination group in both cell lines, followed by birinapant and TRAIL combination for UM-SCC-47, or birinapant and antibody combination for UPCI-SCC-90, which was consistent with the relative percentage of sub-G0 DNA determined by flow cytometry analysis using propidium iodide staining. Enhanced apoptosis/necrosis with the triple combination was observed earlier than with single or dual treatment (12 versus 24 hours post treatment). Specific cell death mechanism was analyzed using pan-caspase (ZVAD), caspase-8 (ZIETD), and RIPK1 (necrostatin) inhibitors. In both UPCI-SCC-90 and UM-SCC-47 cells, caspase inhibition (ZVAD and ZIETD) completely reversed the effects of the double or triple combination treatments, whereas necrostatin did not. This suggests that the TRAILR2 agonist antibody mediated cell death in combination with birinapant is predominantly caspase-8 dependent. These results indicate that the TNF-α, TRAIL, and TRAILR2 agonist antibody sensitized birinapant anti-tumor activity, and triple combination exhibited synergistic effects.

Supported by NIDCD projects ZIA-DC-000016, -73, -74, and the Medical Research Scholars Program.

Citation Format: Yi An, Jun W. Jeon, Lillian Sun, Adeeb Derakhshan, Jianhong Chen, Hui Cheng, Xinping Yang, Christopher Silvin, Carter Van Waes, Zhong Chen. Birinapant enhances death agonist antibody against TRAILR2 anti-tumor activity in HPV-positive head and neck squamous cell carcinomas [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5175.

Enhancing direct cytotoxicity and response to immune checkpoint blockade following ionizing radiation with Wee1 kinase inhibition

Tumor cells activate the G2/M cell cycle checkpoint in response to ionizing radiation (IR) and effector immune cell-derived granzyme B to facilitate repair and survival. Wee1 kinase inhibition reverses the ability of tumor cells to pause at G2/M. Here, we hypothesized that AZD1775, a small molecule inhibitor of Wee1 kinase, could sensitize tumor cells to IR and T-lymphocyte killing and improve responses to combination IR and programmed death (PD)-axis immune checkpoint blockade (ICB). Multiple models of head and neck carcinoma, lung carcinoma and melanoma were used in vitro and in vivo to explore this hypothesis. AZD1775 reversed G2/M cell cycle checkpoint activation following IR, inducing cell death. Combination IR and AZD1775 induced accumulation of DNA damage in M-phase cells and was rescued with nucleoside supplementation, indicating mitotic catastrophe. Combination treatment enhanced control of syngeneic MOC1 tumors in vivo, and on-target effects of systemic AZD1775 could be localized with targeted IR. Combination treatment enhanced granzyme B-dependent T-lymphocyte killing through reversal of additive G2/M cell cycle block induced by IR and granzyme B. Combination IR and AZ1775-enhanced CD8⁺ cell-dependent MOC1 tumor growth control and rate of complete rejection of established tumors in the setting of PD-axis ICB. Functional assays demonstrated increased tumor antigen-specific immune responses in sorted T-lymphocytes. The combination of IR and AZD1775 not only lead to enhanced tumor-specific cytotoxicity, it also enhanced susceptibility to T-lymphocyte killing and responses to PD-axis ICB. These data provide the pre-clinical rationale for the combination of these therapies in the clinical trial setting.

Cisplatin and oxaliplatin induce similar immunogenic changes in preclinical models of head and neck cancer

OBJECTIVES

Prior studies suggest that oxaliplatin is unique among platinum chemotherapy drugs in its ability to enhance anti-tumor immunity, but the immune mechanisms of different platinum chemotherapy drugs have not been previously compared in preclinical models of head and neck squamous cell carcinoma (HNSCC).

MATERIALS AND METHODS

Human HNSCC cell lines were treated with cisplatin or oxaliplatin, then assessed for markers associated with immunogenic cell death (ICD) and antigen processing. A syngeneic mouse model of oral cancer was then used to compare the effects of cisplatin vs. oxaliplatin, alone or in combination with anti-PD-1 immunotherapy, on tumor growth and survival. A subset of spleens and tumors were analyzed for ICD markers and immune cell infiltrates by flow cytometry.

RESULTS

Cisplatin and oxaliplatin both increased cell surface levels of calreticulin, HSP70, MHC class I and PD-L1 in multiple cell lines. Inoculation of immunocompetent mice with cells killed in vitro by either drug resulted in failure of subsequently-injected live tumor cells to establish and grow in a small proportion of animals. Systemic cisplatin and oxaliplatin induced similar tumor growth delay when combined with anti-PD-1 therapy.

CONCLUSIONS

Treatment of HNSCC cells with platinum chemotherapy appears to induce some features of anti-tumor immunity, which may be enhanced by anti-PD-1 therapy. Cisplatin, the standard drug for HNSCC, appears to affect anti-tumor immunity in a similar fashion to oxaliplatin in these preclinical models.

Attenuated TRAF3 Fosters Activation of Alternative NF-κB and Reduced Expression of Antiviral Interferon, TP53, and RB to Promote HPV-Positive Head and Neck Cancers

Human papilloma viruses (HPV) are linked to an epidemic increase in oropharyngeal head and neck squamous cell carcinomas (HNSCC), which display viral inactivation of tumor suppressors TP53 and RB1 and rapid regional spread. However, the role of genomic alterations in enabling the modulation of pathways that promote the aggressive phenotype of these cancers is unclear. Recently, a subset of HPV⁺ HNSCC has been shown to harbor novel genetic defects or decreased expression of TNF receptor-associated factor 3 (TRAF3). TRAF3 has been implicated as a negative regulator of alternative NF-κB pathway activation and activator of antiviral type I IFN response to other DNA viruses. How TRAF3 alterations affect pathogenesis of HPV⁺ HNSCC has not been extensively investigated. Here, we report that TRAF3-deficient HPV⁺ tumors and cell lines exhibit increased expression of alternative NF-κB pathway components and transcription factors NF-κB2/RELB. Overexpression of TRAF3 in HPV⁺ cell lines with decreased endogenous TRAF3 inhibited NF-κB2/RELB expression, nuclear localization, and NF-κB reporter activity, while increasing the expression of IFNA1 mRNA and protein and sensitizing cells to its growth inhibition. Overexpression of TRAF3 also enhanced TP53 and RB tumor suppressor proteins and decreased HPV E6 oncoprotein in HPV⁺ cells. Correspondingly, TRAF3 inhibited cell growth, colony formation, migration, and resistance to TNFα and cisplatin-induced cell death. Conversely, TRAF3 knockout enhanced colony formation and proliferation of an HPV⁺ HNSCC line expressing higher TRAF3 levels. Together, these findings support a functional role of TRAF3 as a tumor suppressor modulating established cancer hallmarks in HPV⁺ HNSCC.Significance: These findings report the functional role of TRAF3 as a tumor suppressor that modulates the malignant phenotype of HPV⁺ head and neck cancers. Cancer Res; 78(16); 4613-26. ©2018 AACR.

Attenuated TRAF3 Fosters Activation of Alternative NF-κB and Reduced Expression of Antiviral Interferon, TP53, and RB to Promote HPV-Positive Head and Neck Cancers

Human papilloma viruses (HPV) are linked to an epidemic increase in oropharyngeal head and neck squamous cell carcinomas (HNSCC), which display viral inactivation of tumor suppressors TP53 and RB1 and rapid regional spread. However, the role of genomic alterations in enabling the modulation of pathways that promote the aggressive phenotype of these cancers is unclear. Recently, a subset of HPV⁺ HNSCC has been shown to harbor novel genetic defects or decreased expression of TNF receptor-associated factor 3 (TRAF3). TRAF3 has been implicated as a negative regulator of alternative NF-κB pathway activation and activator of antiviral type I IFN response to other DNA viruses. How TRAF3 alterations affect pathogenesis of HPV⁺ HNSCC has not been extensively investigated. Here, we report that TRAF3-deficient HPV⁺ tumors and cell lines exhibit increased expression of alternative NF-κB pathway components and transcription factors NF-κB2/RELB. Overexpression of TRAF3 in HPV⁺ cell lines with decreased endogenous TRAF3 inhibited NF-κB2/RELB expression, nuclear localization, and NF-κB reporter activity, while increasing the expression of IFNA1 mRNA and protein and sensitizing cells to its growth inhibition. Overexpression of TRAF3 also enhanced TP53 and RB tumor suppressor proteins and decreased HPV E6 oncoprotein in HPV⁺ cells. Correspondingly, TRAF3 inhibited cell growth, colony formation, migration, and resistance to TNFα and cisplatin-induced cell death. Conversely, TRAF3 knockout enhanced colony formation and proliferation of an HPV⁺ HNSCC line expressing higher TRAF3 levels. Together, these findings support a functional role of TRAF3 as a tumor suppressor modulating established cancer hallmarks in HPV⁺ HNSCC.Significance: These findings report the functional role of TRAF3 as a tumor suppressor that modulates the malignant phenotype of HPV⁺ head and neck cancers. Cancer Res; 78(16); 4613-26. ©2018 AACR.

Clinical efficacy of gene-modified stem cells in adenosine deaminase-deficient immunodeficiency

BACKGROUND

Autologous hematopoietic stem cell transplantation (HSCT) of gene-modified cells is an alternative to enzyme replacement therapy (ERT) and allogeneic HSCT that has shown clinical benefit for adenosine deaminase-deficient (ADA-deficient) SCID when combined with reduced intensity conditioning (RIC) and ERT cessation. Clinical safety and therapeutic efficacy were evaluated in a phase II study.

METHODS

Ten subjects with confirmed ADA-deficient SCID and no available matched sibling or family donor were enrolled between 2009 and 2012 and received transplantation with autologous hematopoietic CD34+ cells that were modified with the human ADA cDNA (MND-ADA) γ-retroviral vector after conditioning with busulfan (90 mg/m2) and ERT cessation. Subjects were followed from 33 to 84 months at the time of data analysis. Safety of the procedure was assessed by recording the number of adverse events. Efficacy was assessed by measuring engraftment of gene-modified hematopoietic stem/progenitor cells, ADA gene expression, and immune reconstitution.

RESULTS

With the exception of the oldest subject (15 years old at enrollment), all subjects remained off ERT with normalized peripheral blood mononuclear cell (PBMC) ADA activity, improved lymphocyte numbers, and normal proliferative responses to mitogens. Three of nine subjects were able to discontinue intravenous immunoglobulin replacement therapy. The MND-ADA vector was persistently detected in PBMCs (vector copy number [VCN] = 0.1-2.6) and granulocytes (VCN = 0.01-0.3) through the most recent visits at the time of this writing. No patient has developed a leukoproliferative disorder or other vector-related clinical complication since transplant.

CONCLUSION

These results demonstrate clinical therapeutic efficacy from gene therapy for ADA-deficient SCID, with an excellent clinical safety profile.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00794508.

FUNDING

Food and Drug Administration Office of Orphan Product Development award, RO1 FD003005; NHLBI awards, PO1 HL73104 and Z01 HG000122; UCLA Clinical and Translational Science Institute awards, UL1RR033176 and UL1TR000124.

Avoiding phagocytosis-related artifact in myeloid derived suppressor cell T-lymphocyte suppression assays

Myeloid-derived suppressor cells (MDSCs) have garnered much attention in recent years as a potential target for altering the immunosuppressive tumor microenvironment in a variety of solid tumor types. The ability to accurately assess the immunosuppressive capacity of MDSCs is fundamental to the development of therapeutic approaches aimed at disabling these immunosuppressive functions. In this article we provide evidence that the use of CD3/28 coated microbeads leads to artefactual T-lymphocyte suppression due to sequestration of beads by MDSCs isolated from the spleens of wild-type mice bearing subcutaneous syngeneic, carcinogen-induced oral cavity carcinomas. Mechanisms of this finding may include early MDSC death and acquisition of phagocytic capacity. These artefactual findings were avoided by eliminating the use of microbeads and instead using plate bound CD3/28 antibody as the T-lymphocyte stimulus. We propose model-specific validation of microbead-based MDSC assays, or use of an alternative stimulation approach such as plate bound CD3/28 antibodies.

Early-onset stroke and vasculopathy associated with mutations in ADA2

BACKGROUND

We observed a syndrome of intermittent fevers, early-onset lacunar strokes and other neurovascular manifestations, livedoid rash, hepatosplenomegaly, and systemic vasculopathy in three unrelated patients. We suspected a genetic cause because the disorder presented in early childhood.

METHODS

We performed whole-exome sequencing in the initial three patients and their unaffected parents and candidate-gene sequencing in three patients with a similar phenotype, as well as two young siblings with polyarteritis nodosa and one patient with small-vessel vasculitis. Enzyme assays, immunoblotting, immunohistochemical testing, flow cytometry, and cytokine profiling were performed on samples from the patients. To study protein function, we used morpholino-mediated knockdowns in zebrafish and short hairpin RNA knockdowns in U937 cells cultured with human dermal endothelial cells.

RESULTS

All nine patients carried recessively inherited mutations in CECR1 (cat eye syndrome chromosome region, candidate 1), encoding adenosine deaminase 2 (ADA2), that were predicted to be deleterious; these mutations were rare or absent in healthy controls. Six patients were compound heterozygous for eight CECR1 mutations, whereas the three patients with polyarteritis nodosa or small-vessel vasculitis were homozygous for the p.Gly47Arg mutation. Patients had a marked reduction in the levels of ADA2 and ADA2-specific enzyme activity in the blood. Skin, liver, and brain biopsies revealed vasculopathic changes characterized by compromised endothelial integrity, endothelial cellular activation, and inflammation. Knockdown of a zebrafish ADA2 homologue caused intracranial hemorrhages and neutropenia - phenotypes that were prevented by coinjection with nonmutated (but not with mutated) human CECR1. Monocytes from patients induced damage in cocultured endothelial-cell layers.

CONCLUSIONS

Loss-of-function mutations in CECR1 were associated with a spectrum of vascular and inflammatory phenotypes, ranging from early-onset recurrent stroke to systemic vasculopathy or vasculitis. (Funded by the National Institutes of Health Intramural Research Programs and others.).

Defects of Regulatory T Cell function In The Wiskott-Aldrich Syndrome. (49.25)

Natural Tregs from both WAS patients and WASp-deficient (WKO) mice were previously reported as unable to suppress the proliferation of conventional T-cells in vitro. Because WAS T-cells have a known defect of IL-2 production and this cytokine is important for the generation of Treg cells induced from naïve T-cells, we assessed the efficiency with which WKO naïve T-cells can differentiate in Tregs and observed a significant defect compared to WT. Such defect was not corrected by increasing concentration of anti-CD3 and TGF-β. Preliminary experiments indicated a role for endogenous IL-2 production in the generation of iTregs and pointed again to the IL-2 pathway as a major determinant of the Treg cells defects in WAS. Furthermore, we previously observed that the impaired suppression of T-cell proliferation could be partially rescued by pre-activation of nTregs. Because activated nTregs are known to be able to induce B-cell apoptosis, we set out to evaluate the function of WKO nTregs on B-cells. We found that pre-activated WKO Treg cells fail to effectively suppress B-cell proliferation. The reduced granzyme-B secretion by WKO nTregs compared to WT, suggest that the defective suppressive activity on B-cells may be due to a degranulation defect of WKO cells. In summary, our data suggest that both natural and induced arms of T regulatory cells are defective in WAS and that defective peripheral Treg induction may be involved in the pathogenesis of autoimmunity in this disease.

Loss-of-function mutations in Rab escort protein 1 (REP-1) affect intracellular transport in fibroblasts and monocytes of choroideremia patients

Background

Choroideremia (CHM) is a progressive X-linked retinopathy caused by mutations in the CHM gene, which encodes Rab escort protein-1 (REP-1), an escort protein involved in the prenylation of Rabs. Under-prenylation of certain Rabs, as a result of loss of function mutations in REP-1, could affect vesicular trafficking, exocytosis and secretion in peripheral cells of CHM patients.

Methodology/Principal Findings

To evaluate this hypothesis, intracellular vesicle transport, lysosomal acidification and rates of proteolytic degradation were studied in monocytes (CD14+ fraction) and primary skin fibroblasts from the nine age-matched controls and thirteen CHM patients carrying 10 different loss-of-function mutations. With the use of pHrodo™ BioParticles® conjugated with E. coli, collagen I coated FluoSpheres beads and fluorescent DQ™ ovalbumin with BODYPY FL dye, we demonstrated for the first time that lysosomal pH was increased in monocytes of CHM patients and, as a consequence, the rates of proteolytic degradation were slowed. Microarray analysis of gene expression revealed that some genes involved in the immune response, small GTPase regulation, transcription, cell adhesion and the regulation of exocytosis were significantly up and down regulated in cells from CHM patients compared to controls. Finally, CHM fibroblasts secreted significantly lower levels of cytokine/growth factors such as macrophage chemoattractant protein-1 (MCP-1), pigment epithelial derived factor (PEDF), tumor necrosis factor (TNF) alpha, fibroblast growth factor (FGF) beta and interleukin (lL)-8.

Conclusions/Significance

We demonstrated for the first time that peripheral cells of CHM patients had increased pH levels in lysosomes, reduced rates of proteolytic degradation and altered secretion of cytokines. Peripheral cells from CHM patients expose characteristics that were not previously recognized and could used as an alternative models to study the effects of different mutations in the REP-1 gene on mechanism of CHM development in human population.

Measurement of proliferative responses of cultured lymphocytes

Measurement of proliferative responses of human lymphocytes is a fundamental technique for the assessment of their biological responses to various stimuli. Most simply, this involves measurement of the number of cells present in a culture before and after the addition of a stimulating agent. This unit contains several different prototype protocols to measure the proliferative response of lymphocytes following exposure to mitogens, antigens, allogeneic or autologous cells, or soluble factors. Each of these protocols can be used in conjunction with an accompanying support protocol which contains methods for pulsing cultures with [3H]thymidine and determining incorporation of [3H]thymidine into DNA or assessing cell proliferation by nonradioactive methods, e.g., reduction of tetrazolium salts (MTT). The protocols described here provide an estimate of DNA synthesis and cell proliferation in an entire cell population, but do not provide information on the proliferation of individual cells. A protocol for CFSE labeling allows specific subpopulations of cells to be separated viably for further analysis.

Dynamic effect of bortezomib on nuclear factor-kappaB activity and gene expression in tumor cells

Nuclear factor-kappaB (NF-kappaB) influences the initiation, progression, and maintenance of diverse cancer types. Despite current therapeutic efforts to block hyperactive NF-kappaB in cancer cells, the in vivo effects of a drug upon this complex pathway are unclear. We monitored NF-kappaB activity and a fast-expressing reporter level simultaneously in head and neck squamous carcinoma cells by quantitative live microscopy. The real-time single cell assay revealed the tumor necrosis factor-alpha-induced oscillation of NF-kappaB was echoed by equally dynamic reporter expression rate. Bortezomib is a proteasome inhibitor whose anticancer action is partly mediated through inhibition of NF-kappaB. When administered to preactivated cells, the drug gave rise to distinct inhibition dynamics, with discrete pulses of reporter induction remaining for hours. These findings suggest that, contrary to a simplistic presumption for a pathway "blockade," the network dynamics and the intracellular pharmacokinetics of the inhibitor must be critically evaluated in developing strategies for optimal intervention of oncogenic pathways.

Gene therapy improves immune function in preadolescents with X-linked severe combined immunodeficiency

Retroviral gene therapy can restore immunity to infants with X-linked severe combined immunodeficiency (XSCID) caused by mutations in the IL2RG gene encoding the common gamma chain (gammac) of receptors for interleukins 2 (IL-2), -4, -7, -9, -15, and -21. We investigated the safety and efficacy of gene therapy as salvage treatment for older XSCID children with inadequate immune reconstitution despite prior bone marrow transplant from a parent. Subjects received retrovirus-transduced autologous peripherally mobilized CD34(+) hematopoietic cells. T-cell function significantly improved in the youngest subject (age 10 years), and multilineage retroviral marking occurred in all 3 children.

Functional identification of kinases essential for T-cell activation through a genetic suppression screen

Activation of T-cells by antigens initiates a complex series of signal-transduction events that are critical for immune responses. While kinases are key mediators of signal transduction networks, several of which have been well characterized in T-cell activation, the functional roles of other kinases remain poorly defined. To address this deficiency, we developed a genetic screen to survey the functional roles of kinases in antigen mediated T-cell activation. A retroviral library was constructed that expressed genetic suppressor elements (GSEs) comprised of peptides and antisense nucleotides derived from kinase cDNAs including members of the STE, CAMK, AGC, CMGC, RGC, TK, TKL, Atypical, and Lipid kinase groups. The retroviral library was expressed in Jurkat T-cells and analyzed for their effect on T-cell activation as monitored by CD69 expression. Jurkat cells were activated by antigen presenting cells treated with superantigen, and sorted for a CD69 negative phenotype by flow cytometry. We identified 19 protein kinases that were previously implicated in T-cell signaling processes and 12 kinases that were not previously linked to T-cell activation. To further validate our approach, we characterized the role of the protein kinase MAP4K4 that was identified in the screen. siRNA studies showed a role for MAP4K4 in antigen mediated T-cell responses in Jurkat and primary T-cells. In addition, by analyzing multiple promoter elements using reporter assays, we have shown that MAP4K4 is implicated in the activation of the TNF-alpha promoter. Our results suggest that this methodology could be used to survey the function of the entire kinome in T-cell activation.

A role for Wiskott-Aldrich syndrome protein in T-cell receptor-mediated transcriptional activation independent of actin polymerization

Wiskott-Aldrich syndrome protein (WASP) plays a key role in cytoskeletal rearrangement and transcriptional activation in T-cells. Recent evidence links WASP and related proteins to actin polymerization by the Arp2/3 complex. To study whether the role of WASP in actin polymerization is coupled to T-cell receptor (TCR)-mediated transcriptional activation, we made a series of WASP deletion mutants and tested them for actin co-localization, actin polymerization, and transcriptional activation of NFAT. A WASP mutant with a deletion in the C-terminal region (WASPDeltaC) that is defective in actin polymerization potentiated NFAT transcription following TCR activation by anti-CD3 and anti-CD3/CD28 antibodies, but not by phorbol 12-myristate 13-acetate/ionomycin. Furthermore, cotransfection of a dominant-active mutant (WASP-WH2-C) for Arp2/3 polymerization did not inhibit NFAT activation. Finally, by analyzing a series of WASP double-domain deletion mutants, we determined that the WASP homology-1 domain is responsible for NFAT transcriptional activation. Our results suggest that WASP activates transcription following TCR stimulation in a manner that is independent of its role in Arp2/3-directed actin polymerization.