Carter Van Waes

Nuclear Factor-κB in Development, Prevention, and Therapy of Cancer

Nuclear factor-κB (NF-κB) is a signal transcription factor that has emerged as an important modulator of altered gene programs and malignant phenotype in development of cancer. Major carcinogens and oncogenic viruses induce NF-κB activation, and a variety of subsequent oncogenic events contribute to a progressive increase in constitutive NF-κB activation as an important common pathway in most forms of cancer. NF-κB target genes promote tumor cell proliferation, survival, migration, inflammation, and angiogenesis. Inhibition of NF-κB has been found to be an important mechanism of action of steroids, nonsteroidal anti-inflammatory drugs, and natural and synthetic compounds that show therapeutic and preventive activity. Newer agents targeting the proteasome, inhibitor-κB kinase, and other upstream kinases involved in NF-κB activation have shown anticancer activity in clinical or preclinical studies.Nuclear factor-κB (NF-κB) is a signal transcription factor that has emerged as an important modulator of altered gene programs and malignant phenotype in development of cancer. Major carcinogens and oncogenic viruses induce NF-κB activation, and a variety of subsequent oncogenic events contribute to a progressive increase in constitutive NF-κB activation as an important common pathway in most forms of cancer. NF-κB target genes promote tumor cell proliferation, survival, migration, inflammation, and angiogenesis. Inhibition of NF-κB has been found to be an important mechanism of action of steroids, nonsteroidal anti-inflammatory drugs, and natural and synthetic compounds that show therapeutic and preventive activity. Newer agents targeting the proteasome, inhibitor-κB kinase, and other upstream kinases involved in NF-κB activation have shown anticancer activity in clinical or preclinical studies.

Constitutive activation of transcription factors NF-?B, AP-1, and NF-IL6 in human head and neck squamous cell carcinoma cell lines that express pro-inflammatory and pro-angiogenic cytokines

We previously reported that human head and neck squamous cell carcinomas (HNSCCs) express the pro‐inflammatory and pro‐angiogenic cytokines interleukin (IL)‐1α, IL‐6, IL‐8, and granulocyte‐macrophage colony‐stimulating factor in vitro and in vivo. The promoter region of the genes encoding these cytokines include binding sites for the transcription factors nuclear factor (NF) κB/Rel A, activator protein‐1 (AP‐1), and CCAAT enhancer‐binding protein β (C/EBPβ, or NF‐IL6), which have been reported to contribute to activation of these cytokine genes. In the study presented here, we examined the activation, composition, and function of these transcription factors in HNSCC cell lines that express pro‐inflammatory cytokines, by using electrophoretic mobility shift and reporter‐gene assays. Constitutive activation of NF‐κB, AP‐1, and NF‐IL6 DNA‐binding proteins was detected. Supershift analysis with antibodies specific for NF‐κB, AP‐1, and NF‐IL6 binding proteins showed that the NF‐κB–binding protein included p65/Rel A and p50; AP‐1 activity included c‐jun, junB, junD, and Fra‐1; and NF‐IL6 included C/EBPβ. Mutational analysis of the NF‐κB, AP‐1, and NF‐IL6 sites in the IL‐8 promoter region showed that NF‐κB and AP‐1 sites contributed to constitutive IL‐8 reporter activity in HNSCC. HNSCC lines that exhibited increased IL‐8 secretion relative to simian virus 40–immortalized and primary keratinocyte cell lines also demonstrated a concordant increase in NF‐κB reporter activity relative to nonmalignant keratinocytes. We concluded that the early transcription factors NF‐κB, AP‐1, and NF‐IL6 are constitutively activated in human HNSCC cell lines and that NF‐κB and AP‐1 promote expression of the pro‐inflammatory and pro‐angiogenic cytokine IL‐8 in HNSCC. The demonstration of the activation of these transcription factors will be helpful in defining the identity and role of these and other early gene products that contribute to pathogenesis of the malignant phenotype in HNSCC and in defining potential targets for pharmacologic and molecular therapy of HNSCC. Mol. Carcinog. 26:119–129, 1999. Published 1999 Wiley‐Liss, Inc.

Effects of pharmacologic antagonists of epidermal growth factor receptor, PI3K and MEK signal kinases on NF-κB and AP-1 activation and IL-8 and VEGF expression in human head and neck squamous cell carcinoma lines†

We previously reported that expression of angiogenesis factors interleukin‐8 (IL‐8) and vascular endothelial growth factor (VEGF) is promoted by coactivation of transcription factors nuclear factor‐kappaB (NF‐κB) and activator protein‐1 (AP‐1) by interleukin‐1α in human head and neck squamous cell carcinomas (HNSCC). However, expression of IL‐1 receptor antagonist incompletely blocked reporter gene activity and cytokine expression, suggesting that other upstream signals may contribute to activation. Overexpression and autocrine activation of epidermal growth factor receptor (EGFR) is detected in 90% of HNSCC, and EGFR inhibitors have been reported to inhibit IL‐8 and VEGF expression, but the intermediary signal pathways and transcription factors by which EGFR modulates proangiogenic factors is unknown. EGFR can activate the phosphotidylinositol‐3 kinase (PI3K) and mitogen‐activated/extracellular signal‐regulated kinase (MEK) pathways, which can potentially modulate activation of NF‐κB and AP‐1, respectively. In our study, we examined the effect of EGF and antagonists of EGFR, PI3K and MEK on NF‐κB and AP‐1 activation and IL‐8 and VEGF expression in HNSCC cell lines UM‐SCC‐9 and 11B in which EGFR is overexpressed and activated. Recombinant EGF induced EGFR phosphorylation, activation of NF‐κB and AP‐1 reporter genes and IL‐8 and VEGF expression, indicating that EGFR can mediate coactivation of both transcription factors and cytokine genes in HNSCC. EGFR antagonist PD153035 and anti‐EGFR antibody C225 completely inhibited EGF‐induced reporter activity and cytokine expression, but only partially inhibited constitutive activity. MEK inhibitor U0126 preferentially blocked AP‐1 activity and expression of both IL‐8 and VEGF, while PI3K inhibitor LY‐294002 or a dominant negative inhibitor‐κB preferentially blocked NF‐κB activation and expression of IL‐8 but not VEGF. EGFR, PI3K and MEK antagonists inhibited growth of HNSCC. We conclude that antagonists of EGFR, PI3K and MEK signal pathways have inhibitory activity against EGFR‐induced NF‐κB and AP‐1 activation, IL‐8 and VEGF expression and growth by HNSCC. Published 2002 Wiley‐Liss, Inc.

Growth Regulated Oncogene-α expression by murine squamous cell carcinoma promotes tumor growth, metastasis, leukocyte infiltration and angiogenesis by a host CXC Receptor-2 dependent mechanism

Growth Regulated Oncogene-α (GRO-α) is an autocrine growth factor in melanoma and is a member of the C-X-C family of chemokines which promote chemotaxis of granulocytes and endothelia through binding to CXC Receptor 2. We found previously that variants of murine squamous cell carcinoma PAM 212 which grow and metastasize more rapidly in vivo constitutively express increased levels of murine GRO-α, designated mGRO-α, or KC. We have examined the possible role of mGRO-α expression in malignant progression of squamous cell carcinoma PAM 212 in homologous BALB/c and BALB CXC Receptor-2 deficient mice. Transfection of the PAM 212 cell line which exhibits low expression of GRO-α and malignant potential with a pActin-KC vector encoding mGRO-α enabled isolation of PAM-KC expressing cell lines. These PAM-KC transfectants displayed an increased rate of growth and metastasis in BALB/c mice, similar to the highly malignant phenotype observed in spontaneously occurring metastatic variants. Furthermore, the PAM-KC tumors showed an increase in infiltration of host leukocytes and CD31+ blood vessels, consistent with increased CXC chemokine activity. The increased growth of PAM-KC cells was attenuated in CXCR-2 deficient mice, indicating that the increased growth was dependent in part upon host cells responsive to the CXC chemokine. Together, these results show that a CXC chemokine such as GRO-α can promote malignant growth of murine squamous cell carcinoma by a host CXCR-2 dependent pathway.

Nuclear Factor-κB is an Important Modulator of the Altered Gene Expression Profile and Malignant Phenotype in Squamous Cell Carcinoma

We reported previously that transcription factor nuclear factor (NF)-κB is constitutively activated in human and murine squamous cell carcinomas (SCCs). The role of NF-κB in the cumulative changes in gene expression with transformation and progression of the murine SCC Pam 212 and after switching off NF-κB by a dominant negative inhibitor κB mutant (IκBαM) was explored by profiling with a 15,000-element cDNA micoarrray. Remarkably, NF-κB modulated the expression of >60% of the 308 genes differentially expressed between normal keratinocytes and metastatic SCCs. NF-κB directly or indirectly modulated expression of programs of genes functionally linked to proliferation, apoptosis, adhesion, and angiogenesis. Among these, changes in expression of cyclin D1, inhibitor of apoptosis-1, mutant Trp53, and β-catenin detected with modulation of NF-κB by microarray were confirmed by Western and Northern blot. NF-κB DNA binding motifs were detected in the promoter of ∼63% of genes showing increased expression and 33% of the genes showing decreased expression. The ACTACAG motif implicated in the NF-κB-dependent down-regulation of mRNA expression of MyoD and Sox9 was detected in the coding portion of about 15% of genes showing increased or decreased expression. Inactivation of NF-κB inhibited malignant phenotypic features including proliferation, cell survival, migration, angiogenesis, and tumorigenesis. These results provide evidence that NF-κB is an important modulator of gene expression programs that contribute to the malignant phenotype of SCC.

Emergence of protein kinase CK2 as a key target in cancer therapy

Protein kinase CK2, a protein serine/threonine kinase, plays a global role in activities related to cell growth, cell death, and cell survival. CK2 has a large number of potential substrates localized in diverse locations in the cell including, for example, NF‐κB as an important downstream target of the kinase. In addition to its involvement in cell growth and proliferation it is also a potent suppressor of apoptosis, raising its key importance in cancer cell phenotype. CK2 interacts with diverse pathways which illustrates the breadth of its impact on the cellular machinery of both cell growth and cell death giving it the status of a “master regulator” in the cell. With respect to cancer, CK2 has been found to be dysregulated in all cancers examined demonstrating increased protein expression levels and nuclear localization in cancer cells compared with their normal counterparts. We originally proposed CK2 as a potentially important target for cancer therapy. Given the ubiquitous and essential for cell survival nature of the kinase, an important consideration would be to target it specifically in cancer cells while sparing normal cells. Towards that end, our design of a tenascin based sub‐50 nm (i.e., less than 50 nm size) nanocapsule in which an anti‐CK2 therapeutic agent can be packaged is highly promising because this formulation can specifically deliver the cargo intracellularly to the cancer cells in vivo. Thus, appropriate strategies to target CK2 especially by molecular approaches may lead to a highly feasible and effective approach to eradication of a given cancer.

Epigenetic modification of SOCS-1 differentially regulates STAT3 activation in response to interleukin-6 receptor and epidermal growth factor receptor signaling through JAK and/or MEK in head and neck squamous cell carcinomas

Signal transducer and activator of transcription 3 (STAT3) has been reported to be activated by interleukin-6 receptor (IL-6R) or epidermal growth factor receptor (EGFR) in head and neck squamous cell carcinomas (HNSCC), which may have important implications for responsiveness to therapeutics targeted at EGFR, IL-6R, or intermediary kinases. Suppressor of cytokine signaling-1 (SOCS-1) has been implicated recently in the negative regulation of IL-6R/Janus-activated kinase (JAK)–mediated activation of STAT3, suggesting that SOCS-1 could affect alternative activation of STAT3 by EGFR, IL-6R, and associated kinases. We investigated whether epigenetic modification of SOCS-1 affects STAT3 activation in response to IL-6R-, EGFR-, JAK-, or mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK)–mediated signal activation. STAT3 was predominantly activated by IL-6R via Jak1/Jak2 in HNSCC lines UMSCC-9 and UMSCC-38 in association with transcriptional silencing of SOCS-1 by hypermethylation. In UMSCC-11A cells with unmethylated SOCS-1, STAT3 activation was regulated by both EGFR and IL-6R via a JAK-independent pathway involving MEK. Pharmacologic inhibitors of JAK and MEK and expression of SOCS-1 following demethylation or transient transfection inhibited STAT3 activation and cell proliferation and induced cell apoptosis in corresponding cell lines. Hypermethylation of SOCS-1 was found in about one-third of human HNSCC tissues, making it a potentially relevant marker for STAT-targeted therapy in HNSCC patients. We conclude that SOCS-1 methylation status can differentially affect STAT3 activation by IL-6R and EGFR through JAK or MEK in different HNSCC and response to pharmacologic antagonists. Identifying the potential factors and the regulatory pathways in STAT3 activation has important implications for the development and selection of molecularly targeted therapy in HNSCC. [Mol Cancer Ther 2006;5(1):8–19]

Nuclear Factor-κB–Related Serum Factors as Longitudinal Biomarkers of Response and Survival in Advanced Oropharyngeal Carcinoma

Purpose: Cytokines and growth factors modulated by transcription factor nuclear factor-κB and secreted by tumor and stromal cells are detectable in serum of patients with advanced cancers, including head and neck squamous cell carcinomas (SCC). Longitudinal changes in these serum factors could be early biomarkers of treatment response and survival. Experimental Design: Interleukin (IL)-6, IL-8, growth-related oncogene-1 (GRO-1), vascular endothelial growth factor (VEGF), and hepatocyte growth factor (HGF) concentrations were determined by Luminex multiplex assay using serum obtained at baseline and every 3 months in a prospective study of 30 patients with locally advanced (stage III/IV) oropharyngeal SCC receiving chemoradiation therapy. The relationship between baseline and direction of change in individual and multiple cytokines with cause-specific and disease-free survival was determined by Cox proportional hazards models and Kaplan-Meier survival analysis. Statistical analyses included adjustment for smoking status and response to chemoradiation. Results: Three-year cause-specific and disease-free survival was 74.4% and 68.9%. Nonsmoking history (P = 0.05) and higher baseline VEGF (P = 0.003) correlated with increased survival. Longitudinal increases in levels of individual factors predicted decreased cause-specific survival when adjusted for smoking history [IL-6: relative risk (RR), 3.8; 95% confidence interval (95% CI), 2.0-7.4; P = 0.004; IL-8: RR, 1.6; 95% CI, 1.2-2.2; P = 0.05; VEGF: RR, 3.0; 95% CI, 1.6-5.6; P = 0.01; HGF: RR, 2.9; 95% CI, 1.9-4.4; P = 0.02; and GRO-1: RR, 1.2; 95% CI, 1.1-1.3; P = 0.02]. For a given individual, large increases in the upper quartile for any three or more factors predicted poorer cause-specific survival compared with patients with two or fewer large increases in factor levels (P = 0.004). Conclusions: Pretreatment VEGF levels and longitudinal change in IL-6, IL-8, VEGF, HGF, and GRO-1 may be useful as biomarkers for response and survival in patients with locally advanced oropharyngeal and head and neck SCC treated with chemoradiation.

Early responses to adenoviral-mediated transfer of the aquaporin-1 cDNA for radiation-induced salivary hypofunction

No conventional therapy exists for salivary hypofunction in surviving head and neck cancer patients with Radiation Therapy Oncology Group late grade 2–3 toxicity. We conducted a phase I clinical trial to test the safety and biologic efficacy of serotype 5, adenoviral-mediated aquaporin-1 cDNA transfer to a single previously irradiated parotid gland in 11 subjects using an open label, single-dose, dose-escalation design (AdhAQP1 vector; four dose tiers from 4.8 × 107 to 5.8 × 109 vector particles per gland). Treated subjects were followed at scheduled intervals. Multiple safety parameters were measured and biologic efficacy was evaluated with measurements of parotid salivary flow rate. Symptoms were assessed with a visual analog scale. All subjects tolerated vector delivery and study procedures well over the 42-d study period reported. No deaths, serious adverse events, or dose-limiting toxicities occurred. Generally, few adverse events occurred, and all were considered mild or moderate. No consistent changes were found in any clinical chemistry and hematology parameters measured. Objective responses were seen in six subjects, all at doses <5.8 × 109 vector particles per gland. Five of these six subjects also experienced subjective improvement in xerostomia. AdhAQP1 vector delivery to a single parotid gland was safe and transfer of the hAQP1 cDNA increased parotid flow and relieved symptoms in a subset of subjects.

2-Methoxyestradiol Inhibits Hypoxia-Inducible Factor 1α, Tumor Growth, and Angiogenesis and Augments Paclitaxel Efficacy in Head and Neck Squamous Cell Carcinoma

Purpose: Head and neck squamous cell carcinomas have been reported to overexpress hypoxia-inducible factor (HIF)-1α, a transcription factor that promotes expression of angiogenesis factors and resistance to programmed and therapy-induced cell death. 2-Methoxyestradiol (2ME2) is a natural compound with HIF-1α inhibitory activity that is currently being evaluated in phase 1 and 2 clinical trials for advanced solid tumors and multiple myeloma. To our knowledge, this is the first study to evaluate the effects of 2ME2 in head and neck squamous cell carcinoma. Experimental Design: In the present study, we investigated the effects of 2ME2 alone and in combination with paclitaxel, an active agent in recurrent or advanced head and neck squamous cell carcinoma. Results: 2ME2 exhibited antiproliferative and cytotoxic effects in a panel of five head and neck squamous cell carcinoma cell lines in the 0.5 to 10 μmol/L range, including induction of G2-M blockade, caspase-3/7 activation, and apoptosis at 48 hours. 2ME2 resulted in decreased nuclear HIF-1α–binding activity and affected the expression of downstream genes, such as bid, a proapoptotic bcl-2 family member, and vascular endothelial growth factor, a proangiogenic cytokine. The up-regulation of Bid (57.5% at 12 hours, P < 0.0006) and inhibition of vascular endothelial growth factor secretion (57.7% at 24 hours, P < 0.015; and 50.3% at 48 hours, P < 0.0006) could be partially attributed to the effects on HIF-1α, because HIF-1α small interfering RNAs produced similar effects. Finally, in vivo, in a xenograft model of head and neck squamous cell carcinoma using UM-SCC-11A cells, 2ME2 exhibited antitumor and antiangiogenic activity, as measured by CD31 immunostaining. Conclusions: These results provide support for the use of 2ME2 in combination with paclitaxel for the treatment of recurrent or advanced head and neck squamous cell carcinoma.