Selective inhibition of NF-κB suppresses bone invasion by oral squamous cell carcinoma in vivo

Anticancer effects of gossypetin from Hibiscus sabdariffa in oral squamous cell carcinoma

OBJECTIVE

Gossypetin, isolated from Hibiscus sabdariffa L, has been shown to have various pharmacological effects including anti-inflammatory and antibacterial activity against various diseases. However, since the effect of gossypetin in oral cancer remains to be reported, we aimed to investigate the anticancer activity and mechanisms of gossypetin in oral squamous cell carcinoma (OSCC).

METHODOLOGY

The proliferation of OSCC cells was evaluated by cell viability and soft agar colony assays. The effects of gossypetin on the migration and invasion of OSCC cells was investigated by wound healing and transwell invasion assays, respectively. Apoptosis and cell cycle arrest were measured by flow cytometry. Moreover, the anticancer mechanism of gossypetin in OSCC cells was analyzed by western blotting.

RESULTS

Gossypetin inhibited the proliferation, migration, and invasion of OSCC cells and induced apoptosis by upregulating the Bax/Bcl-2 ratio and cell cycle arrest at the G2/M phase. Furthermore, gossypetin regulated the activation of extracellular signal-regulated kinase and nuclear factor-kappa B.

CONCLUSION

Results showed that gossypetin inhibits the proliferation, migration, and invasion of OSCC cells and triggers apoptosis and cell cycle arrest in OSCC. Therefore, gossypetin has the potential for use as a chemopreventive agent in oral cancer.

Nuciferine Inhibits Oral Squamous Cell Carcinoma Partially through Suppressing the STAT3 Signaling Pathway

Oral squamous cell carcinoma (OSCC) poses a significant obstacle to the worldwide healthcare system. Discovering efficient and non-toxic medications is crucial for managing OSCC. Nuciferine, an alkaloid with an aromatic ring, is present in the leaves of Nelumbo nucifera. It has been proven to play a role in multiple biological processes, including the inhibition of inflammation, regulation of the immune system, formation of osteoclasts, and suppression of tumors. Despite the demonstrated inhibitory effects of nuciferine on different types of cancer, there is still a need for further investigation into the therapeutic effects and potential mechanisms of nuciferine in OSCC. Through a series of in vitro experiments, it was confirmed that nuciferine hindered the growth, movement, and infiltration, while enhancing the programmed cell death of OSCC cells. Furthermore, the administration of nuciferine significantly suppressed the signal transducer and activator of transcription 3 (STAT3) signaling pathway in comparison to other signaling pathways. Moreover, the activation of the STAT3 signaling pathway by colivelin resulted in the reversal of nuciferine-suppressed OSCC behaviors. In vivo, we also showed the anti-OSCC impact of nuciferine using the cell-based xenograft (CDX) model in nude mice. Nonetheless, colivelin diminished the tumor-inhibiting impact of nuciferine, suggesting that nuciferine might partially impede the advancement of OSCC by suppressing the STAT3 signaling pathway. Overall, this research could offer a fresh alternative for the pharmaceutical management of OSCC.

Tumour Necrosis Factor Alpha (TNF-α) and Oral Squamous Cell Carcinoma

Uncovering the inflammatory mechanisms underpinning initiation, progression, and promotion of oral squamous cell carcinoma (OSCC) development is fundamental to the rational pursuit of targeted therapeutics. Here we present a review of the current knowledge of the role of TNF-α in the aetiology, pathogenesis, and potential therapies with regards to OSCC. TNF-α is worthy of particular attention in OSCC, with its presence demonstrated to enhance cell proliferation and its downregulation demonstrated to inhibit proliferation and migration in other carcinomas in both in vitro and in vivo models and oral cancer patients. Increased TNF-α in the OSCC tumour microenvironment has been demonstrated to favour invasion through promotion of firstly the pro-inflammatory, pro-invasive phenotypes of OSCC cells and secondly its paracrine mechanism mediating recruitment and activation of inflammatory cells. Polymorphisms affecting the gene expression of TNF-α have been strongly associated with an increased risk for oral squamous cell carcinoma. A number of studies have considered TNF-α within biofluids, including saliva and serum, as a potential biomarker for the early detection of OSCC, as well as its staging, differentiation, and prognosis. The broad and multifaceted role that TNF-α plays in many inflammatory states presents an obvious confounder, particularly with demonstrated increased TNF-α levels in common oral disease states. Lastly, biologic agents targeting TNF-α are currently in clinical use for immune-mediated inflammatory rheumatological and gastrointestinal diseases. There is the potential that these biological agents might have an adjunctive role in OSCC prevention and treatment.

ERK-mediated upregulation of matrix metalloproteinase-2 promotes the invasiveness in human oral squamous cell carcinoma (OSCC)

BACKGROUND

Loco-regional invasion is commonly found in oral squamous cell carcinoma (OSCC) and is associated with its poor survival rate. Matrix metalloproteinase-2 (MMP-2) has been implicated in OSCC progression, but its regulation is poorly understood.

MATERIALS AND METHODS

Here, one hundred twenty-seven different post-operated human oral cancer tissue samples were analyzed. The messenger RNA (mRNA) expression, protein expression, and MMP-2 activity and MT1-MMP, TIMP-2, and TFs (NFκB, AP1, Sp1, and Twist) were observed semi-quantitative RT-PCR, western blotting, and gelatin zymography. In addition, OSCC derived Cal-27, SCC4/9 cells, photochemical ECGC, and MAPK-pathway inhibitor PD98059 were utilized for in vitro testing and wound healing assay.

RESULT

s: Increased protein and activity level of MMP-2 was detected in non-invasive (N₀) and invasive (N_1-3) oral tumors as compared to the control (adjacent normal) samples. MMP-2 protein and mRNA expression were positively associated with the TFs and MT1-MMP, negatively associated with TIMP-2 expression. Similarly, the MMP-2 expression/activity was related to several signal-transduction pathways like ERK1/2 and wnt-β-catenin pathways. Treatment of ECGC/MEK inhibitor (PD98059) diminished MMP-2 activity and invasion/migration potential in OSCC.

CONCLUSION

Our research suggests that the ERK1/2 driven overexpression/activation of MMP-2 was linked with the overall OSCC invasion and metastasis. Treatment of MEK inhibitor (PD98059) and ECGC diminished MMP-2 activity and thus could be exploited as a therapeutic strategy to control the invasive OSCC.

Bone morphogenetic protein induces bone invasion of melanoma by epithelial-mesenchymal transition via the Smad1/5 signaling pathway

Oral malignant melanoma, which frequently invades the hard palate or maxillary bone, is extremely rare and has a poor prognosis. Bone morphogenetic protein (BMP) is abundantly expressed in bone matrix and is highly expressed in malignant melanoma, inducing an aggressive phenotype. We examined the role of BMP signaling in the acquisition of an aggressive phenotype in melanoma cells in vitro and in vivo. In five cases, immunohistochemistry indicated the phosphorylation of Smad1/5 (p-Smad1/5) in the nuclei of melanoma cells. In the B16 mouse and A2058 human melanoma cell lines, BMP2, BMP4, or BMP7 induces morphological changes accompanied by the downregulation of E-cadherin, and the upregulation of N-cadherin and Snail, markers of epithelial-mesenchymal transition (EMT). BMP2 also stimulates cell invasion by increasing matrix metalloproteinase activity in B16 cells. These effects were canceled by the addition of LDN193189, a specific inhibitor of Smad1/5 signaling. In vivo, the injection of B16 cells expressing constitutively activated ALK3 enhanced zygoma destruction in comparison to empty B16 cells by increasing osteoclast numbers. These results suggest that the activation of BMP signaling induces EMT, thus driving the acquisition of an aggressive phenotype in malignant melanoma.

p130Cas induces bone invasion by oral squamous cell carcinoma by regulating tumor epithelial-mesenchymal transition and cell proliferation

Bone invasion is a critical factor in determining the prognosis of oral squamous cell carcinoma (OSCC) patients. Transforming growth factor β (TGF-β) is abundantly expressed in the bone matrix and is involved in the acquisition of aggressiveness by tumors. TGF-β is also important to cytoskeletal changes during tumor progression. In this study, we examined the relationship between TGF-β signaling and cytoskeletal changes during bone invasion by OSCC. Immunohistochemical staining of OSCC samples from five patients showed the expression of p130Cas (Crk-associated substrate) in the cytoplasm and phosphorylated Smad3 expression in the nucleus in OSCC cells. TGF-β1 induced the phosphorylation of Smad3 and p130Cas, as well as epithelial-mesenchymal transition (EMT) accompanied by the downregulation of the expression of E-cadherin, a marker of epithelial cells, and the upregulation of the expression of N-cadherin, or Snail, a marker of mesenchymal cells, in human HSC-2 cells and mouse squamous cell carcinome VII (SCCVII) cells. SB431542, a specific inhibitor of Smad2/3 signaling, abrogated the TGF-β1-induced phosphorylation of p130Cas and morphological changes. Silencing p130Cas using an short hairpin RNA (shRNA) or small interfering RNA in SCCVII cells suppressed TGF-β1-induced cell migration, invasion, EMT and matrix metalloproteinase-9 (MMP-9) production. Compared with control SCCVII cells, SCCVII cells with silenced p130Cas strongly suppressed zygomatic and mandibular destruction in vivo by reducing the number of osteoclasts, cell proliferation and MMP-9 production. Taken together, these results showed that the expression of TGF-β/p130Cas might be a new target for the treatment of OSCC bone invasion.

[Advances in molecular mechanisms of bone invasion by oral cancer]

Bone invasion by oral cancer is a common clinical problem, which affects the choice of treatment and predicts a poor prognosis. Unfortunately, the molecular mechanism of this phenomenon has not been fully elucidated. Current studies have revealed that oral cancer cells modulate the formation and function of osteoclasts through the expression of a series of signal molecules. Many signal pathways are involved in this process, of which receptor activator of nuclear factor-κB ligand/receptor activator of nuclear factor-κB/osteoprotegerin signaling pathway attracted much attention. In this review, we introduce recent progress in molecular mechanisms of bone invasion by oral cancer.

Short-term RANKL exposure initiates a neoplastic transcriptional program in the basal epithelium of the murine salivary gland

Although salivary gland cancers comprise only ∼3-6% of head and neck cancers, treatment options for patients with advanced-stage disease are limited. Because of their rarity, salivary gland malignancies are understudied compared to other exocrine tissue cancers. The comparative lack of progress in this cancer field is particularly evident when it comes to our incomplete understanding of the key molecular signals that are causal for the development and/or progression of salivary gland cancers. Using a novel conditional transgenic mouse (K5:RANKL), we demonstrate that Receptor Activator of NFkB Ligand (RANKL) targeted to cytokeratin 5-positive basal epithelial cells of the salivary gland causes aggressive tumorigenesis within a short period of RANKL exposure. Genome-wide transcriptomic analysis reveals that RANKL markedly increases the expression levels of numerous gene families involved in cellular proliferation, migration, and intra- and extra-tumoral communication. Importantly, cross-species comparison of the K5:RANKL transcriptomic dataset with The Cancer Genome Atlas cancer signatures reveals the strongest molecular similarity with cancer subtypes of the human head and neck squamous cell carcinoma. These studies not only provide a much needed transcriptomic resource to mine for novel molecular targets for therapy and/or diagnosis but validates the K5:RANKL transgenic as a preclinical model to further investigate the in vivo oncogenic role of RANKL signaling in salivary gland tumorigenesis.

MicroRNA‑199a‑5p functions as a tumor suppressor in oral squamous cell carcinoma via targeting the IKKβ/NF‑κB signaling pathway

MicroRNAs (miRNAs) have been shown to have a significant role in the progression of several types of cancer, including oral squamous cell carcinoma (OSCC). However, the biological function and regulatory mechanisms of miRNAs in OSCC remain to be fully elucidated. The aim of the present study was to investigate the role of miRNAs in OSCC and the relevant mechanism. Using a microarray, it was found that miRNA (miR)-199a-5p was one of the most downregulated miRNAs in OSCC tissues. A low expression of miR-199a-5p was closely associated with tumor differentiation, lymph node metastasis, tumor-node-metastasis stage, and overall survival rate. Functionally, the overexpression of miR-199a-5p suppressed cell proliferation, induced G0/G1 cell cycle arrest, and promoted the apoptosis of Tca8113 and SCC-4 cells. Subsequently, inhibitor of nuclear factor-κB (NF-κB) kinase β (IKKβ), an important regulator of NF-κB activation, was identified as a direct target of miR-199-5p. An inverse correlation was found between miR-199a-5p and IKKβ in tumor tissues. Further investigations revealed that the overexpression of IKKβ efficiently abrogated the influences caused by the overexpression of miR-199a-5p. It was also found that the miR-199a-5p-mediated anticancer effects were dependent on the inhibition of NF-κB activation. These findings indicate that miR-199a-5p functions as a tumor suppressor through regulation of the NF-κB pathway by targeting IKKβ in OSCC.

Autoregulation of RANK ligand in oral squamous cell carcinoma tumor cells

Oral squamous cell carcinoma (OSCC) is the most common malignancy among oral cancers and shows potent activity for local bone invasion. Receptor activator of nuclear factor κB (RANK) ligand (RANKL) is critical for bone-resorbing osteoclast formation. We previously demonstrated that OSCC tumor cells express high levels of RANKL. In this study, confocal microscopy demonstrated RANKL specific receptor, RANK expression in OSCC tumor cell lines (SCC1, SCC12, and SCC14a). We also confirmed the expression of RANK and RANKL in primary human OSCC tumor specimens. However, regulatory mechanisms of RANKL expression and a functional role in OSCC tumor progression are unclear. Interestingly, we identified that RANKL expression is autoregulated in OSCC tumor cells. The RANKL specific inhibitor osteoprotegerin (OPG) treatment to OSCC cells inhibits autoregulation of RANKL expression. Further, we showed conditioned media from RANKL CRISPR-Cas9 knockout OSCC cells significantly decreased osteoclast formation and bone resorption activity. In addition, RANKL increases OSCC tumor cell proliferation. RANKL treatment to OSCC cells demonstrated a dose-dependent increase in RANK intracellular adaptor protein, TRAF6 expression, and activation of IKK and IκB signaling molecules. We further identified that transcription factor NFATc2 mediates autoregulation of RANKL expression in OSCC cells. Thus, our results implicate RANKL autoregulation as a novel mechanism that facilitates OSCC tumor cell growth and osteoclast differentiation/bone destruction.

TNF-Alpha Promotes Invasion and Metastasis via NF-Kappa B Pathway in Oral Squamous Cell Carcinoma

Background

Recent evidence reveals that the inflammatory microenvironment is associated with tumor migration, invasion, and metastasis. Tumor necrosis factor-α (TNF-α) play a vital role in regulation of the inflammatory process in tumor development. Nuclear factor-kappa B (NF-κB) is one of the key transcription factors which regulate processes in tumor promotion. The aim of this study was to explore the role of NF-κB on the invasion and migration of oral squamous cell carcinoma (OSCC).

Material/Methods

The IKKβ and p65 mRNA and protein levels were determined by quantitative RT-PCR and western blot. Wound scratch healing assays and transwell migration assays were used to evaluate the effect of TNF-α and BAY11-7082 on the migration of the OSCC cell lines (HN4, HN6, and CAL27).

Results

We observed a significant increase of the expression level of IKKβ and p65 in OSCC cells from the experimental group at 24 h, 48 h, and 72 h after TNF-α stimulation. Invasion and metastasis of OSCC cells was obviously improved after the TNF-α stimulation. Invasion and metastasis ability of OSCC cells was inhibited in the suppression group, and no significant changes were observed in expression level of IKKβ and p65 after the use of BAY11-7082.

Conclusions

Our results suggest that TNF-α enhances the invasion and metastasis ability of OSCC cells via the NF-κB signaling pathway.

Immunocompromised and immunocompetent mouse models for head and neck squamous cell carcinoma

Mouse models can closely mimic human oral squamous epithelial carcinogenesis, greatly expand the in vivo research possibilities, and play a critical role in the development of diagnosis, monitoring, and treatment of head and neck squamous cell carcinoma. With the development of the recent research on the contribution of immunity/inflammation to cancer initiation and progression, mouse models have been divided into two categories, namely, immunocompromised and immunocompetent mouse models. And thus, this paper will review these two kinds of models applied in head and neck squamous cell carcinoma to provide a platform to understand the complicated histological, molecular, and genetic changes of oral squamous epithelial tumorigenesis.

Synergistic Effect of Sorafenib and Radiation on Human Oral Carcinoma in vivo

Oral squamous cell carcinoma often causes bone invasion resulting in poor prognosis and affects the quality of life for patients. Herein, we combined radiation with sorafenib, to evaluate the combination effect on tumor progression and bone erosion in an in situ human OSCC-bearing mouse model. Treatment procedure were arranged as following groups: (a) normal (no tumor); (b) control (with tumor); (c) sorafenib (10 mg/kg/day); (d) radiation (single dose of 6 Gy); (e) pretreatment (sorafenib treatment for 3 days prior to radiation), and (f) concurrent treatment (sorafenib and radiation on the same day). The inhibition of tumor growth and expression level of p65 of NF-κB in tumor tissues were the most significant in the pretreatment group. EMSA and Western blot showed that DNA/NF-κB activity and the expressions of NF-κB-associated proteins were down-regulated. Notably, little to no damage in mandibles and zygomas of mice treated with combination of sorafenib and radiation was found by micro-CT imaging. In conclusion, sorafenib combined with radiation suppresses radiation-induced NF-κB activity and its downstream proteins, which contribute to radioresistance and tumorigenesis. Additionally, bone destruction is also diminished, suggesting that combination treatment could be a potential strategy against human OSCC.

IL-1β promotes malignant transformation and tumor aggressiveness in oral cancer

Chronic inflammation, coupled with alcohol, betel quid, and cigarette consumption, is associated with oral squamous cell carcinoma (OSCC). Interleukin-1 beta (IL-1β) is a critical mediator of chronic inflammation and implicated in many cancers. In this study, we showed that increased pro-IL-1β expression was associated with the severity of oral malignant transformation in a mouse OSCC model induced by 4-Nitroquinolin-1-oxide (4-NQO) and arecoline, two carcinogens related to tobacco and betel quid, respectively. Using microarray and quantitative PCR assay, we showed that pro-IL-1β was upregulated in human OSCC tumors associated with tobacco and betel quid consumption. In a human OSCC cell line TW2.6, we demonstrated nicotine-derived nitrosamine ketone (NNK) and arecoline stimulated IL-1β secretion in an inflammasome-dependent manner. IL-1β treatment significantly increased the proliferation and dysregulated the Akt signaling pathways of dysplastic oral keratinocytes (DOKs). Using cytokine antibodies and inflammation cytometric bead arrays, we found that DOK and OSCC cells secreted high levels of IL-6, IL-8, and growth-regulated oncogene-α following IL-1β stimulation. The conditioned medium of IL-1β-treated OSCC cells exerted significant proangiogenic effects. Crucially, IL-1β increased the invasiveness of OSCC cells through the epithelial-mesenchymal transition (EMT), characterized by downregulation of E-cadherin, upregulation of Snail, Slug, and Vimentin, and alterations in morphology. These findings provide novel insights into the mechanism underlying OSCC tumorigenesis. Our study suggested that IL-1β can be induced by tobacco and betel quid-related carcinogens, and participates in the early and late stages of oral carcinogenesis by increasing the proliferation of dysplasia oral cells, stimulating oncogenic cytokines, and promoting aggressiveness of OSCC.

Interpretation of immunohistochemistry data of tumor should consider microenvironmental factors

The influence of tumor surrounding microenvironment is often neglected when immunohistochemistry is performed to investigate tumor properties and search biomarkers of cancer. This study was designed to evaluate whether the influence of tumor microenvironment on biological features of tumor cells should be taken into account for interpretation of the immunohistochemistry data of tumor specimens. In this study, we showed an example by using three tumor cell lines (HeLa, WSU-HN6, and Tca83) to establish tumor-caused bone destruction models in nude mice and then to investigate the influence of bone marrow microenvironment (BMM) on biological features of tumor cells. Immunohistochemistry results showed that, compared with tumor cells located outside of BMM, tumor cells located inside of BMM presented huge differences in the expression of inflammation-related proteins including tumor necrosis factor-α (TNF-α), TNF receptor-associated factor protein-6 (TRAF-6), phosphorylated-NF-κB p65 (p-p65), interleukin (IL)-6 and IL-11, matrix metalloproteinases including MMP-1, MMP-2, MMP-9, and MMP-13; and osteogenesis-related proteins including runt-related transcription factor 2 (RUNX2), bone sialoprotein (BSP), and osteocalcin (OCN) in all the models. However, when we compared the cell line pair derived from different sites (outside and inside of BMM, respectively) of the same HeLa tumor sample by real-time PCR, Western blot, and immunocytochemistry, the differences aforementioned in tumor tissues were not found. In addition, we verified that normal human bone marrow could not cause the above changes detected in vivo. Our results suggested that tumor-modified microenvironment could give the new biological features of the invaded tumor cells. Therefore, we should consider the influence of the surrounding microenvironment on tumor cells when we analyze tumor properties using immunohistochemistry.

The novel IκB kinase β inhibitor IMD-0560 prevents bone invasion by oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) cells display significantly augmented nuclear factor-κB (NF-κB) activity, and inhibiting this activity suppresses malignant tumor characteristics. Thus, we evaluated the effect of IMD-0560, a novel inhibitor of IκB kinase (IKK) β that is under assessment in a clinical trial of rheumatoid arthritis, on bone invasion by the mouse OSCC cell line SCCVII. We examined the inhibitory effects of IMD-0560 on NF-κB activity and tumor invasion using human OSCC cell lines and SCCVII cells in vitro. Using a mouse model of jaw bone invasion by SCCVII cells, we assessed the inhibitory effect of IMD-0560 on jaw bone invasion, tumor growth, and matrix degradation in vivo. IMD-0560 suppressed the nuclear translocation of NF-κB and the degradation of IκBα in OSCC cells. IMD-0560 also inhibited invasion by suppressing matrix metalloproteinase-9 (MMP-9) production in OSCC cells. IMD-0560 protected against zygoma and mandible destruction by SCCVII cells, reduced the number of osteoclasts by inhibiting receptor activator of NF-κB ligand (RANKL) expression in osteoblastic cells and SCCVII cells, increased SCCVII cell death and suppressed cell proliferation and MMP-9 production in SCCVII cells. Based on these results, IMD-0560 may represent a new therapeutic agent for bone invasion by OSCC cells.

Aberrant expression of NF-κB in liver fluke associated cholangiocarcinoma: implications for targeted therapy

Background

Up-regulation and association of nuclear factor kappa B (NF-κB) with carcinogenesis and tumor progression has been reported in several malignancies. In the current study, expression of NF-κB in cholangiocarcinoma (CCA) patient tissues and its clinical significance were determined. The possibility of using NF-κB as the therapeutic target of CCA was demonstrated.

Methodology

Expression of NF-κB in CCA patient tissues was determined using immunohistochemistry. Dehydroxymethylepoxyquinomicin (DHMEQ), a specific NF-κB inhibitor, was used to inhibit NF-κB action. Cell growth was determined using an MTT assay, and cell apoptosis was shown by DNA fragmentation, flow cytometry and immunocytofluorescent staining. Effects of DHMEQ on growth and apoptosis were demonstrated in CCA cell lines and CCA-inoculated mice. DHMEQ-induced apoptosis in patient tissues using a histoculture drug response assay was quantified by TUNEL assay.

Principal Findings

Normal bile duct epithelia rarely expressed NF-κB (subunits p50, p52 and p65), whereas all CCA patient tissues (n  =  48) over-expressed all NF-κB subunits. Inhibiting NF-κB action by DHMEQ significantly inhibited growth of human CCA cell lines in a dose- and time-dependent manner. DHMEQ increased cell apoptosis by decreasing the anti-apoptotic protein expressions–Bcl-2, XIAP–and activating caspase pathway. DHMEQ effectively reduced tumor size in CCA-inoculated mice and induced cell apoptosis in primary histocultures of CCA patient tissues.

Conclusions

NF-κB was over-expressed in CCA tissues. Inhibition of NF-κB action significantly reduced cell growth and enhanced cell apoptosis. This study highlights NF-κB as a molecular target for CCA therapy.

A phase I clinical trial of systemically delivered NEMO binding domain peptide in dogs with spontaneous activated B-cell like diffuse large B-cell lymphoma

Activated B-Cell (ABC) Diffuse Large B-Cell Lymphoma (DLBCL) is a common, aggressive and poorly chemoresponsive subtype of DLBCL, characterized by constitutive canonical NF-κB signaling. Inhibition of NF-κB signaling leads to apoptosis of ABC-DLBCL cell lines, suggesting targeted disruption of this pathway may have therapeutic relevance. The selective IKK inhibitor, NEMO Binding Domain (NBD) peptide effectively blocks constitutive NF-κB activity and induces apoptosis in ABC-DLBCL cells in vitro. Here we used a comparative approach to determine the safety and efficacy of systemic NBD peptide to inhibit constitutive NF-κB signaling in privately owned dogs with spontaneous newly diagnosed or relapsed ABC-like DLBCL. Malignant lymph nodes biopsies were taken before and twenty-four hours after peptide administration to determine biological effects. Intravenous administration of <2 mg/kg NBD peptide was safe and inhibited constitutive canonical NF-κB activity in 6/10 dogs. Reductions in mitotic index and Cyclin D expression also occurred in a subset of dogs 24 hours post peptide and in 3 dogs marked, therapeutically beneficial histopathological changes were identified. Mild, grade 1 toxicities were noted in 3 dogs at the time of peptide administration and one dog developed transient subclinical hepatopathy. Long term toxicities were not identified. Pharmacokinetic data suggested rapid uptake of peptide into tissues. No significant hematological or biochemical toxicities were identified. Overall the results from this phase I study indicate that systemic administration of NBD peptide is safe and effectively blocks constitutive NF-κB signaling and reduces malignant B cell proliferation in a subset of dogs with ABC-like DLBCL. These results have potential translational relevance for human ABC-DLBCL.

Inhibitors of NF-kappaB reverse cellular invasion and target gene upregulation in an experimental model of aggressive oral squamous cell carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC) is diagnosed in 640,000 patients yearly with a poor (50%) 5-year survival rate that has not changed appreciably in decades.

PAITENTS AND METHODS

To investigate molecular changes that drive OSCC progression, cDNA microarray analysis was performed using human OSCC cells that form aggressive poorly differentiated tumors (SCC25-PD) in a murine orthotopic xenograft model compared to cells that produce well-differentiated tumors (SCC25-WD).

RESULTS

As this analysis revealed that 59 upregulated genes were NF-κB target genes, the role of NF-κB activation in alteration of the transcriptional profile was evaluated. The mRNA and protein upregulation of a panel NF-κB target genes was validated by real-time qPCR and immunohistochemistry. Additionally, nuclear translocation of RelA was greatly increased in SCC25-PD, increased nuclear RelA was observed in oral tumors initiated with SCC25-PD compared with tumors initiated by SCC25-WD, and nuclear RelA correlated with stage of disease on two human OSCC tissue microarrays. Treatment of SCC25-PD cells with the IKKβ-inhibitor sc-514, that effectively prevents RelA phosphorylation on Ser 536, reversed nuclear-translocation of RelA and strongly inhibited NF-κB gene activation. Furthermore, blocking the phosphorylation of RelA using the MSK1/2 inhibitor SB 747651A significantly reduced the mRNA upregulation of a subset of target genes. Treatment with sc-514 or SB747651A markedly diminished cellular invasiveness.

CONCLUSIONS

These studies support a model wherein NF-κB is constitutively active in aggressive OSCC, while blocking the NF-κB pathway reduces NF-κB target gene upregulation and cellular invasiveness.

Intra-articular nuclear factor-κB blockade ameliorates collagen-induced arthritis in mice by eliciting regulatory T cells and macrophages

Nuclear factor (NF)-κB is a transcription factor implicated in the pathogenesis of autoimmune disorders such as rheumatoid arthritis (RA). Here we have examined the effect of intra-articular administration of the IKK inhibitor, NEMO-binding domain peptide (NBD), on the severity of collagen-induced arthritis (CIA). NBD peptides were injected intra-articularly into the knee joints of DBA/1J mice after the onset of disease. Collagen-injected mice given a scrambled peptide served as controls. Arthritis severity was determined by visual examination of paws. Intra-articular NBD injection reduced the arthritis score and ameliorated morphological signs of bone destruction compared to the controls. Serum levels of type-II collagen-specific immunoglobulin (Ig)G2a antibodies were lower in NBD-treated mice versus the control mice, whereas the levels of type-II collagen-specific IgG1 antibodies were increased by NBD treatment. NBD treatment diminished the proinflammatory cytokines interleukin (IL)-17 and interferon (IFN)-γ in serum, but increased the regulatory cytokine IL-10. NBD-treated CIA mice exhibited significantly higher percentages and numbers of forkhead box protein 3 (FoxP3(+)) CD4(+) CD25(+) regulatory T cells than controls. Immunofluorescence analysis of NBD-treated mice revealed that FoxP3 and Ym1, a marker of alternatively activated macrophages, were juxtaposed to each other within draining inguinal lymph nodes. Intra-articular administration of NBD peptide is effective as an experimental therapy in a murine model of RA. Nevertheless, the intra-articular treatment modality is still associated with systemic effects on the immune system.

Peptide-based delivery to bone

Peptides are attractive as novel therapeutic reagents, since they are flexible in adopting and mimicking the local structural features of proteins. Versatile capabilities to perform organic synthetic manipulations are another unique feature of peptides compared to protein-based medicines, such as antibodies. On the other hand, a disadvantage of using a peptide for a therapeutic purpose is its low stability and/or high level of aggregation. During the past two decades, numerous peptides were developed for the treatment of bone diseases, and some peptides have already been used for local applications to repair bone defects in the clinic. However, very few peptides have the ability to form bone themselves. We herein summarize the effects of the therapeutic peptides on bone loss and/or local bone defects, including the results from basic studies. We also herein describe some possible methods for overcoming the obstacles associated with using therapeutic peptide candidates.

Effect of NF-κB inhibitors on the chemotherapy-induced apoptosis of the colon cancer cell line HT-29

This study aimed to investigate the impact of the combined use of the nuclear factor-κB (NF-κB) inhibitors pyrrolidine dithiocarbamate (PDTC), bortezomib or SN50, and the chemotherapy agents arsenic acid (As₂O₃), fluorouracil (5FU), oxaliplatin or paclitaxel on the growth and apoptosis of HT-29 cells. Cell morphology was observed using inverted microscopy, and cell viability and apoptosis were assessed using the MTT assay and flow cytometry, respectively. The activities of NF-κB were analyzed by western blotting and electrophoretic mobility shift assay (EMSA). Cell growth was significantly inhibited by As₂O₃, oxaliplatin and paclitaxel in a time- and concentration-dependent manner (P<0.05), while 5FU inhibited cell growth in a time-dependent manner only (P<0.05). The growth inhibition rate and apoptosis induction ratio were increased following the combined treatment of the chemotherapy agent and NF-κB inhibitor. The expression of NF-κB p65 was upregulated when cells were treated with a chemotherapy drug, however it was downregulated following combined treatment or treatment with an NF-κB inhibitor alone. In conclusion, an NF-κB inhibitor combined with a chemotherapy drug effectively inhibited cell proliferation, induced cell apoptosis and inhibited NF-κB activity to enhance the chemotherapeutic sensitivity of HT-29 cells.