Interleukin-8 as a modulator of response to bevacizumab in preclinical models of head and neck squamous cell carcinoma

A Microfluidic 3D-Tumor-Spheroid Model for the Evaluation of Targeted Therapies from Angiogenesis-Related Cytokines at the Single Spheroid Level

Angiogenesis is a key player in drug resistance to targeted therapies for breast cancer. The average expression of angiogenesis-related cytokines is widely associated with the treatments of target therapies for a population of cells or spheroids, overlooking the distinct responses for individuals. In this work, a highly integrated microfluidic platform is developed for the generation of monodisperse multicellular tumor spheroids (MTSs), drug treatments, and the measurement of cytokines for individual MTSs in a single chip. The platform allows the correlation evaluation between cytokine secretion and drug treatment at the level of individual spheroids. For validation, quantities of six representative proangiogenic cytokines are tested against treatments with four model drugs at varying times and concentrations. By applying a linear regression model, significant correlations are established between cytokine secretion and the treated drug concentration for individual spheroids. The proposed platform provides a high-throughput method for the investigation of the molecular mechanism of the cytokine response to targeted therapies and paves the way for future drug screening using predictive regression models at the single-spheroid level.

Targeted blockade of interleukin-8 negates metastasis and chemoresistance via Akt/Erk-NFκB axis in oral cancer

BACKGROUND

The tumor microenvironment plays a significant role in tumor growth, metastasis and chemoresistance via dysregulated signaling pathways. Toward this, an inflammatory chemokine, interleukin-8 (IL-8), is overexpressed in various cancers and is involved in tumor progression and chemoresistance. However, the mechanistic role of IL-8 in mediating metastasis and chemoresistance in oral squamous cell carcinoma (OSCC) is not known.

METHODS AND RESULTS

In the present study, we evaluated the effect of IL-8 in regulating metastasis as well as chemoresistance in OSCC cell lines. For this, IL-8 was blocked exogenously using neutralizing IL-8 monoclonal antibody and IL-8 levels were enhanced by exogenous supply of recombinant human IL-8 (rhIL-8) to OSCC cells. The epithelial-to-mesenchymal transition (EMT) was evaluated using qPCR, migration by scratch/wound healing assay and invasion ability using transwell assay. rIL-8 induced chemoresistance was studied by apoptosis assay and the nuclear localization of NFκB using immunocytochemistry. IL-8 was significantly overexpressed in OSCC patients and cell lines. While exogenous blockade of IL-8 significantly reduced EMT, migration and invasion potential in OSCC cells, IL-8 overexpression upregulated these cellular traits thereby confirming the role of IL-8 in OSCC metastasis. Exogenous blockade of IL-8 also reversed chemoresistance in cisplatin resistant OSCC subline via NFκB signaling.

CONCLUSION

IL-8 plays a crucial role in OSCC metastasis and its targeted blockade can help in management of cisplatin resistance.

Attenuating Adaptive VEGF-A and IL8 Signaling Restores Durable Tumor Control in AR Antagonist-Treated Prostate Cancers

Inhibiting androgen signaling using androgen signaling inhibitors (ASI) remains the primary treatment for castrate-resistant prostate cancer. Acquired resistance to androgen receptor (AR)-targeted therapy represents a major impediment to durable clinical response. Understanding resistance mechanisms, including the role of AR expressed in other cell types within the tumor microenvironment, will extend the clinical benefit of AR-targeted therapy. Here, we show the ASI enzalutamide induces vascular catastrophe and promotes hypoxia and microenvironment adaptation. We characterize treatment-induced hypoxia, and subsequent induction of angiogenesis, as novel mechanisms of relapse to enzalutamide, highlighting the importance of two hypoxia-regulated cytokines in underpinning relapse. We confirmed AR expression in CD34+ vascular endothelium of biopsy tissue and human vascular endothelial cells (HVEC). Enzalutamide attenuated angiogenic tubule formation and induced cytotoxicity in HVECs in vitro, and rapidly induced sustained hypoxia in LNCaP xenografts. Subsequent reoxygenation, following prolonged enzalutamide treatment, was associated with increased tumor vessel density and accelerated tumor growth. Hypoxia increased AR expression and transcriptional activity in prostate cells in vitro. Coinhibition of IL8 and VEGF-A restored tumor response in the presence of enzalutamide, confirming the functional importance of their elevated expression in enzalutamide-resistant models. Moreover, coinhibition of IL8 and VEGF-A resulted in a durable, effective resolution of enzalutamide-sensitive prostate tumors. We conclude that concurrent inhibition of two hypoxia-induced factors, IL8 and VEGF-A, prolongs tumor sensitivity to enzalutamide in preclinical models and may delay the onset of enzalutamide resistance.

IMPLICATIONS

Targeting hypoxia-induced signaling may extend the therapeutic benefit of enzalutamide, providing an improved treatment strategy for patients with resistant disease.

Antitumor effects of bevacizumab in combination with fluoropyrimidine drugs on human oral squamous cell carcinoma

Vascular endothelial growth factor (VEGF) serves an important role in new blood vessel formation or angiogenesis, which is a critical event in tumor growth and metastasis. Bevacizumab is a humanized monoclonal antibody against VEGF-A, whereas S-1 is a fluoropyrimidine antineoplastic agent that induces apoptosis in various types of cancer cells. The present study evaluated the antitumor effects of bevacizumab in combination with 5-fluorouracil (5-FU) or S-1 against oral squamous cell carcinoma (OSCC) in vitro and in vivo. Two human OSCC cell lines were used, namely the high VEGF-A-expressing HSC-2 cells and the low VEGF-A-expressing SAS cells. MTT assay was used to evaluate the effect of bevacizumab and/or 5-FU against HSC-2 and SAS cell proliferation. Additionally, the antitumor effect of bevacizumab was evaluated alone and in combination with S-1 against HSC-2 tumors in nude mice. S-1 (6.9 mg/kg/day) was administered orally every day for 3 weeks, and bevacizumab (5 ml/kg/day) was injected intraperitoneally twice per week for 3 weeks. Apoptotic cells in mouse tumors were detected using the TUNEL method, and cell proliferation and microvessel density (MVD) were determined by immunohistochemical staining of Ki-67 and CD31, respectively. Bevacizumab alone did not inhibit OSCC cell proliferation in vitro, and did not exhibit any synergistic inhibitory effect in combination with 5-FU in vitro. However, combined bevacizumab and S-1 therapy exerted synergistic and significant antitumor effects in vivo on HSC-2 tumor xenografts, and induced apoptosis in tumor cells. Furthermore, this combination therapy led to decreased MVD and cell proliferative abilities, as well as increased apoptosis in residual tumors. The present findings suggested that the bevacizumab plus S-1 combination therapy may exert antitumor effects in high VEGF-A-expressing OSCC cells.

HOX Genes Family and Cancer: A Novel Role for Homeobox B9 in the Resistance to Anti-Angiogenic Therapies

Simple Summary

The inhibition of angiogenesis, relying on the use of drugs targeting the VEGF signaling pathway, has become one of the main strategies for cancer treatment. However, the intrinsic and acquired resistance to this type of therapy limit its efficacy. Thus, the identification of novel therapeutic targets is urgently needed. The resistance to anti-angiogenic treatment often occurs through the activation of alternative VEGF independent signaling pathways and recruitment of bone marrow-derived pro-angiogenic cells in the tumor microenvironment. HOX genes are key regulators of embryonic development, also involved in angiogenesis and in cancer progression. HOXB9 upregulation occurs in many types of cancer and it has been identified as a critical transcription factor involved in tumour resistance to anti-angiogenic drugs. Indeed, HOXB9 modulates the expression of alternative pro-angiogenic secreted factors in the tumour microenvironment leading tumor escape from the anti-angiogenic treatments. Hence, HOXB9 could serves as a novel therapeutic target to overcome the resistance to anti-angiogenic therapies.

Abstract

Angiogenesis is one of the hallmarks of cancer, and the inhibition of pro-angiogenic factors and or their receptors has become a primary strategy for cancer therapy. However, despite promising results in preclinical studies, the majority of patients either do not respond to these treatments or, after an initial period of response, they develop resistance to anti-angiogenic agents. Thus, the identification of a novel therapeutic target is urgently needed. Multiple mechanisms of resistance to anti-angiogenic therapy have been identified, including the upregulation of alternative angiogenic pathways and the recruitment of pro-angiogenic myeloid cells in the tumor microenvironment. Homeobox containing (HOX) genes are master regulators of embryonic development playing a pivotal role during both embryonic vasculogenesis and pathological angiogenesis in adults. The importance of HOX genes during cancer progression has been reported in many studies. In this review we will give a brief description of the HOX genes and their involvement in angiogenesis and cancer, with particular emphasis on HOXB9 as a possible novel target for anti-angiogenic therapy. HOXB9 upregulation has been reported in many types of cancers and it has been identified as a critical transcription factor involved in resistance to anti-angiogenic drugs.

Small extracellular vesicle-bound vascular endothelial growth factor secreted by carcinoma-associated fibroblasts promotes angiogenesis in a bevacizumab-resistant manner

The blood vessel growth inhibitor bevacizumab targets vascular endothelial growth factor (VEGF), a crucial regulator of angiogenesis. Recently, small extracellular vesicles (sEVs) have been demonstrated to be important vehicles in the transport of growth factors to target cells. In this study, we isolated primary carcinoma-associated fibroblasts (CAFs) from four human oral squamous cell carcinoma (OSCC) specimens. Compared with other non-extracellular vesicle components, CAF-derived sEVs were found to be the main regulators of angiogenesis. The ability of CAF sEVs to activate VEGF receptor 2 (VEGFR2) signaling in human umbilical vein endothelial cells (HUVEC) was dependent on the association between sEVs and VEGF. In addition, sEV-bound VEGF secreted by CAFs further activated VEGFR2 signaling in HUVEC in a bevacizumab-resistant manner. VEGF was found to interact with heparan sulfate proteoglycans on the CAF sEV surface and could be released by heparinase I/III. The bioactivity of the dissociated VEGF was retained in vitro and in vivo and could be neutralized by bevacizumab. These findings suggest that the combined use of heparinase and bevacizumab might inhibit angiogenesis in patients with high levels of sEV-bound VEGF.

The interaction of interleukin-8 and PTEN inactivation promotes the malignant progression of head and neck squamous cell carcinoma via the STAT3 pathway

Interleukin-8 (IL-8) expression correlates with poor prognosis in many cancers, including head and neck squamous cell carcinoma (HNSCC), but the underlying mechanism is poorly understood. In this study, we found that overexpression of IL-8 correlated with poor outcome in HNSCC patients. IL-8 significantly increased cellular proliferation, migration, and invasion ability both in vitro and in vivo, which could be blocked by a CXCR1/2 inhibitor. IL-8 promoted the expression of MMP2, MMP9, snail, and vimentin in HNSCC cells. Furthermore, IL-8 could inactivate PTEN via phosphorylation, and then inactivated PTEN affected the phosphorylation of STAT3. Recombinant PTEN that internalized in cytoplasm decreased the expression of phosphorylated STAT3, while knockdown of PTEN led to the increased expression of phosphorylated STAT3. A STAT3 inhibitor could reverse the upregulation of invasion-associated proteins mediated by IL-8 stimulation. Furthermore, overexpression of snail and inactivated PTEN jointly promoted the autocrine effect of IL-8 on tumor cells. Last, there were positive correlations between IL-8 and snail, vimentin expression in HNSCC tissues. In summary, our study demonstrates that PTEN acts as a novel "molecular switch" to regulate IL-8/STAT3 signaling, promoting the progression of HNSCC, and indicating that this pathway may be a potential therapeutic target for HNSCC.

Progress in targeted therapeutic drugs for oral squamous cell carcinoma

With the rapid development of biomedicine, people have a deeper understanding with the biological characteristics of malignant tumors, and begin to notice that in most tumors, there are over-expression of several molecules such as epidermal growth factor receptor(EGFR), vascular endothelial growth factor (VEGF) and its receptors,mammalian target of rapamycin(mTOR),programmed cell death receptor-1(PD-1),cyclin-dependent kinases(CDKs) and so on, whose levels are closely related to the prognosis of tumors. It has been found that the drugs targeting the above molecules can significantly improve the survival rate of cancer patients, and have the advantages of high selectivity, low toxicity and high therapeutic index. Targeted drugs, as new ones in the field of cancer, have achieved good efficacy in most tumor treatments. Oral cancer is an aggressive malignant tumour that is prone to relapse and metastasis. More than 90% of them are squamous cell carcinoma, and the 5-year survival rate remains at about 50%-60%.The proposing of targeted therapy opens up a new way for the treatment of oral cancer and brings dawn to patients with advanced diseases. Currently,a variety of targeted therapeutic drugs are being tested in various clinical trials in patients with oral squamous cell carcinoma(OSCC)·In this paper, we discuss the research progress of targeted therapeutic drugs in the treatment of OSCC in recent years.

An update on biomarkers of potential benefit with bevacizumab for breast cancer treatment: Do we make progress?

As the first monoclonal antibody against vascular endothelial growth factor (VEGF), bevacizumab (BEV) is a definitely controversial antiangiogenic therapy in breast cancer. The initial excitement over improvements in progression-free survival (PFS) with BEV was tempered by an absence of overall survival (OS) benefit and serious adverse effects. Missing targeted population urged us to identify the predictive biomarkers for BEV efficacy. In this review we focus on the research in breast cancer and provide recent investigations on clinical, radiological, molecular and gene profiling markers of BEV efficacy, including the new results from randomized phase III clinical trials evaluating the efficacy of BEV in combination with comprehensive biomarker analyses. Current evidences indicate some predictive values for genetic variants, molecular imaging, VEGF pathway factors or associated factors in peripheral blood and gene profiling. The current challenge is to validate those potential biomarkers and implement them into clinical practice.

Interaction between human osteosarcoma and mesenchymal stem cells via an interleukin-8 signaling loop in the tumor microenvironment

BACKGROUND

Osteosarcoma (OS) is the representative primary malignant bone tumor with the highest incidence. It is known that malignant phenotypes of OS, such as proliferation, invasion, and metastasis, are significantly influenced not only by characteristics of the tumor itself, but also by the surrounding microenvironment. In other words, OS is considered to utilize cells in the vicinity of the tumor by changing the characteristics of these cells. Direct intercellular contact is believed to be important for this phenomenon. In the present study, we hypothesized that an interaction mediated by a humoral factor, requiring no cellular contact, might play a significant role in the progression of OS.

METHODS

We developed a new co-culture model, using OS cells and mesenchymal stem cells (MSCs) without cellular contact, and found that both cell types expressed IL-8 at a high level, and FAK in OS cells was phosphorylated leading to an increase in the metastatic potential of the tumor in the co-culture condition.

RESULTS

It was revealed that OS cells formed a loop of signal cross-talk in which they released IL-8 as a paracrine factor, stimulating MSCs to express IL-8, and received IL-8 released by MSCs to accelerate IL-8 expression in OS cells. Administration of anti-IL-8 antibody resulted in the inhibition of FAK expression, its downstream signaling, and the invasive potential of the OS cells, resulting in decrease in metastatic lesions.

CONCLUSION

The present study might lead not only to the clarification of a new molecular mechanism of invasion and metastasis of OS, but also to the development of a new therapeutic strategy of blocking IL-8 in OS.

Effects of peritumoral bevacizumab injection against oral squamous cell carcinoma in a nude mouse xenograft model: A preliminary study

Angiogenesis serves a crucial role in tumor growth. Vascular endothelial growth factor (VEGF) is a potent regulator of tumor angiogenesis and is highly expressed in oral squamous cell carcinoma (OSCC). Bevacizumab, which binds to VEGF-A, inhibits the biological activity of VEGF and is clinically administered by intravenous injection. As intravenous chemotherapy intensifies the side effects experienced by OSCC patients, an alternative treatment option is desirable, particularly for older patients with OSCC who present with systemic disease complications. Generally, local injections of antitumor agents enhance tumoricidal activity and decrease side effects. However, the antitumor effects of peritumoral bevacizumab injections in OSCC are not fully understood. Therefore, the present study examined the effects of peritumoral bevacizumab injections in an experimental nude mouse model of OSCC through immunohistochemical staining for cluster of differentiation (CD)31 and α-smooth muscle actin (α-SMA) and apoptosis assays. It was identified that peritumoral injections of bevacizumab significantly inhibited tumor growth in OSCC xenografts compared with peritumoral saline injections or no treatment (controls), and it was also revealed that treatment with bevacizumab significantly reduced CD31- and α-SMA-positive microvessel density (P<0.01) and increased level of tumor cell apoptosis (P<0.01) compared with the controls. In conclusion, these results collectively support the experimental basis for the clinical development of peritumoral bevacizumab injections for the treatment of OSCC.

Interleukin-8 in cancer pathogenesis, treatment and follow-up

Interleukin-8 (CXCL8) was originally described asa chemokine whose main function is the attraction of a polymorphonuclear inflammatory leukocyte infiltrate acting on CXCR1/2. Recently, it has been found that tumors very frequently coopt the production of this chemokine, which in this malignant context exerts different pro-tumoral functions. Reportedly, these include angiogenesis, survival signaling for cancer stem cells and attraction of myeloid cells endowed with the ability to immunosuppress and locally provide growth factors. Given the fact that in cancer patients IL-8 is mainly produced by tumor cells themselves, its serum concentration has been shown to correlate with tumor burden. Thus, IL-8 serum concentrations have been shown to be useful asa pharmacodynamic biomarker to early detect response to immunotherapy. Finally, because of the roles that IL-8 plays in favoring tumor progression, several therapeutic strategies are being developed to interfere with its functions. Such interventions hold promise, especially for therapeutic combinations in the field of cancer immunotherapy.

Signature of cytokines and angiogenic factors (CAFs) defines a clinically distinct subgroup of gastric cancer

BACKGROUND

Little is known about cytokine and angiogenic factors (CAFs) in gastric cancer (GC) in terms of tumor classification and prognostic value. Here, we aimed to correlate CAF signature with overall survival (OS) in GC.

METHODS

We measured pretreatment serum levels of 52 kinds of CAFs in 68 GC patients who were treated with fluoropyrimidine and platinum combination chemotherapy using multiplex bead immunoassays and enzyme-linked immunosorbent assay. We evaluated correlations between CAF levels and pathological features and OS.

RESULTS

Three distinct patient groups were identified: one with high levels of proangiogenic factors, another with high levels of proinflammatory factors, and the other with high levels of both factors. Eleven CAFs [interleukin (IL)-2 receptor-alpha, growth-regulated alpha protein, hepatocyte growth factor, macrophage colony-stimulating factor, stromal cell-derived factor, IL-6, IL-8, IL-10, interferon-gamma, vascular endothelial growth factor, and osteopontin] were independently correlated with poor OS. Clustering analysis of these 11 CAFs revealed distinct high and low 11-CAF signature groups. High 11-CAF signature was associated with shorter OS (10.1 vs. 17.9 months, p = 0.026) along with poor performance status, and the presence of signet ring cell components in multivariate analysis of OS (HR 1.76, p = 0.029). The patients' traditional clinicopathological characteristics were not significantly different between the high and low 11-CAF signature groups.

CONCLUSION

Serum CAF profiling differentiated GC patient groups. A high 11-CAF signature could identify GC patients with a poor prognosis when treated with standard chemotherapy who need urgent new treatment strategies.

Association of IL-8 and eNOS polymorphisms with clinical outcomes in bevacizumab-treated breast cancer patients: an exploratory analysis

BACKGROUND

The role of bevacizumab in metastatic breast cancer is controversial. Identification of predictive biomarkers could help to select patients who really benefit from it. We evaluated the association of angiogenesis-related gene polymorphisms with the treatment outcome of bevacizumab in metastatic breast cancer patients.

PATIENTS AND METHODS

eNOS-786T/C and -894G/T, IL-8-251T/A genomic polymorphisms were assessed in 31 metastatic breast cancer patients treated with bevacizumab plus chemotherapy in the first-line setting. Testing for association between each polymorphism and treatment outcome was performed.

RESULTS

Patients with IL-8 251 AA genotype showed a significantly lower progression-free survival in each combination comparison: "TT" vs "AA" (13 vs 8 months; p = 0.008); TT vs TA vs AA (13 vs 11 vs 8 months; p = 0.02); TT vs TA +AA (13 vs 11 months; p = 0.01); TT + TA vs AA (12 vs 8 months; p = 0.01) and a lower overall survival when compared with TT +TA genotype (26 vs 51 months, p = 0.04). Patients carrying eNOS 894 TT genotype showed a statistically significant lower progression-free survival than patients with GG genotype (11.5 vs 26.5 months; p = 0.04) with no differences in the overall survival. No association with response rate was found with any of the polymorphisms analyzed.

CONCLUSION

These findings suggest that IL-8 251T/A and eNOS-894 G/T polymorphisms might have a role in predicting treatment outcome of bevacizumab in metastatic breast cancer. Our results are hypothesis generating and need to be confirmed in larger clinical trials.

3D culture broadly regulates tumor cell hypoxia response and angiogenesis via pro-inflammatory pathways

Oxygen status and tissue dimensionality are critical determinants of tumor angiogenesis, a hallmark of cancer and an enduring target for therapeutic intervention. However, it is unclear how these microenvironmental conditions interact to promote neovascularization, due in part to a lack of comprehensive, unbiased data sets describing tumor cell gene expression as a function of oxygen levels within three-dimensional (3D) culture. Here, we utilized alginate-based, oxygen-controlled 3D tumor models to study the interdependence of culture context and the hypoxia response. Microarray gene expression analysis of tumor cells cultured in 2D versus 3D under ambient or hypoxic conditions revealed striking interdependence between culture dimensionality and hypoxia response, which was mediated in part by pro-inflammatory signaling pathways. In particular, interleukin-8 (IL-8) emerged as a major player in the microenvironmental regulation of the hypoxia program. Notably, this interaction between dimensionality and oxygen status via IL-8 increased angiogenic sprouting in a 3D endothelial invasion assay. Taken together, our data suggest that pro-inflammatory pathways are critical regulators of tumor hypoxia response within 3D environments that ultimately impact tumor angiogenesis, potentially providing important therapeutic targets. Furthermore, these results highlight the importance of pathologically relevant tissue culture models to study the complex physical and chemical processes by which the cancer microenvironment mediates new vessel formation.

Treatment of metastatic colorectal cancer with or without bevacizumab: can the neutrophil/lymphocyte ratio predict the efficiency of bevacizumab?

BACKGROUND

The purpose of this study was to analyze the predictive value of neutrophil/lymphocyte ratio (NLR) to better clarify which patient groups will benefit the most from particular treatments like bevacizumab.

MATERIALS AND METHODS

A total of 245 treatment-naive metastatic colorectal cancern (mCRC) patients were retrospectively enrolled and divided into 2 groups: 145 group A patients were treated with chemotherapy in combination with bevacizumab, and 100 group B patients were treated as above without bevacizumab.

RESULTS

Group A patients had better median overall survival (OS) and progression-free survival (PFS) (24.0 and 9.0 months) than group B patients (20 and 6.0 months) (p=0.033; p=0.015). In patients with low NLR, OS and PFS were significantly longer in group A patients (27 vs 18 months, p=0.001; 11 vs 7 months, p=0.017).

CONCLUSIONS

We conclude that NLR, a basal cancer related inflammation marker, is associated with the resistance to bevacizumab- based treatments in mCRC patients.

rhCSF3 accelerates the proliferation of human melanocytes in culture through binding CSF3R and the expression of CSF3R transcripts

Melanogenic paracrine and autocrine cytokine networks have recently been discovered in vitro between melanocytes and other types of skin cells. Granulocyte colony-stimulating factor receptor (CSF3R) controls the survival, proliferation and differentiation of many kinds of cells, including neutrophils. To understand the function of CSF3R and recombinant human granulocyte colony-stimulating factor (rhCSF3) on melanocyte proliferation, this study compared the expression of CSF3R and the effects of rhCSF3 in primary human melanocytes, neutrophils and HEL 92.1.7 cells. The results show that CSF3R is localized in the cytoplasm and on cell membranes of melanocytes and neutrophils. The percentage of CSF3R(+) melanocytes was higher than CSF3R(+) HEL 92.1.7 cells, but was lower than CSF3R(+) neutrophils. Both CSF3R mRNA and CSF3R protein levels in melanocytes were higher than in HEL 92.1.7 cells, but were lower than in neutrophils. Treatment with rhCSF3 increased the proliferation of human melanocytes, but not their tyrosinase activity. Transcripts of CSF3R in human melanocytes, M14, A375 melanoma and A431 squamous cell carcinoma cells were also detected. Expression of the CSF3R V3 transcript was lower in melanocytes than in M14, A375 melanoma and A431 squamous cell carcinoma cells. In conclusion, rhCSF3 can promote melanocyte proliferation through CSF3R without affecting tyrosinase activity.

The great escape; the hallmarks of resistance to antiangiogenic therapy

The concept of antiangiogenic therapy in cancer treatment has led to the approval of different agents, most of them targeting the well known vascular endothelial growth factor pathway. Despite promising results in preclinical studies, the efficacy of antiangiogenic therapy in the clinical setting remains limited. Recently, awareness has emerged on resistance to antiangiogenic therapies. It has become apparent that the intricate complex interplay between tumors and stromal cells, including endothelial cells and associated mural cells, allows for escape mechanisms to arise that counteract the effects of these targeted therapeutics. Here, we review and discuss known and novel mechanisms that contribute to resistance against antiangiogenic therapy and provide an outlook to possible improvements in therapeutic approaches.

Magnitude of influenza virus replication and cell damage is associated with interleukin-6 production in primary cultures of human tracheal epithelium

Primary cultures of human tracheal epithelium were infected with influenza viruses to examine the relationships between the magnitude of viral replication and infection-induced cell damage and cytokine production in airway epithelial cells. Infection with four strains of the type A influenza virus increased the detached cell number and lactate dehydrogenase (LDH) levels in the supernatants. The detached cell number and LDH levels were related to the viral titers and interleukin (IL)-6 levels and the nuclear factor kappa B (NF-κB) p65 activation. Treatment of the cells with an anti-IL-6 receptor antibody and an NF-κB inhibitor, caffeic acid phenethyl ester, reduced the detached cell number, viral titers and the LDH levels and improved cell viability after infection with the pandemic influenza virus [A/Sendai-H/N0633/2009 (H1N1) pdm09]. A caspase-3 inhibitor, benzyloxycarbonyl-DEVD-fluoromethyl ketone, reduced the detached cell number and viral titers. Influenza viral infection-induced cell damage may be partly related to the magnitude of viral replication, NF-κB-p65-mediated IL-6 production and caspase-3 activation.

The chemokine receptor-CXCR2 plays a critical role in the invasion and metastases of oral squamous cell carcinoma in vitro and in vivo

BACKGROUND

Oral squamous cell carcinoma (OSCC) is one of the most common cancers in the world with about 50% survival rate over 5 years. OSCC has a highly invasive potency and frequently metastasizes to the cervical lymph nodes, which is the principle reason leading to poor prognosis. CXCR2, the receptor of CXC chemokines, has been reported to be involved in invasion and metastasis in multiple types of malignancy. However, the accurate role of CXCR2 in OSCC has been little noticed.

METHODS

In this study, we determined the expression of CXCR2 in OSCC using immunohistochemical staining (IHC) and analyzed the association between the expression of CXCR2 and the biobehavior of OSCC. Then, we established stable OSCC cell lines with interference of CXCR2 and observed the effect of CXCR2 knockdown on cell proliferation, migration, invasion, and morphological changes in vitro and in vivo.

RESULTS

CXCR2 was positively expressed in 55.3% of OSCC patients and was statistically associated with the high cervical lymph node metastasis in OSCC. CXCR2 silencing markedly inhibited migration and invasion of OSCC cells in vitro and in vivo. Moreover, CXCR2 silencing led to morphological changes and decreased lamellipodial structures in OSCC cells. However, CXCR2 silencing showed no effect on proliferation of OSCC cells in vitro and in vivo.

CONCLUSIONS

CXCR2 plays a critical role in the invasion and metastases of OSCC. And it is probably by regulating actin cytoskeletal remodeling that CXCR2 takes part in the invasion and metastases of OSCC.

Interleukin-8 and interleukin-17 for cancer

Pro-inflammatory cytokines have been associated with chronic inflammation and inflammatory diseases. Increased levels of interleukins (ILs) have been associated with inflammatory disease exacerbation. ILs levels have been observed to be associated with advance stage cancer for several types of cancer and a poor prognostic maker for malignant disease. Moreover; increased levels of cytokines induce tumorigenesis. There are several paradigms such as the hepatocellular carcinoma induced from chronic inflammation of an underlying hepatitis. In the current review, we will focus on IL-8 and -17. These two ILs as in the case of others, induce neo-angiogenesis through activation of the vascular endothelial growth (VEGF) factor pathway. Additionally, they enhance the activity of matrix metalloproteinase-2 and -9 (MMP-2,-9) which in turn increase the metastatic activity of the underlying malignancy. Inhibition of cytokine production could be a potential treatment both for chronic inflammatory diseases and tumor modulation. Local microenvironment modulation could be applied in surgery resected patients as in the case of lung cancer in order to enhance the local immune activity.

Proangiogenic tumor proteins as potential predictive or prognostic biomarkers for bevacizumab therapy in metastatic colorectal cancer

Tumor biomarkers to more accurately predict a patient's response to a given therapy are much needed in oncology practice. For metastatic colorectal cancer the anti-vascular endothelial growth factor (VEGF) monoclonal antibody bevacizumab is now commonly included in first-line therapy regimens and has led to modest but significant improvements in patient outcomes compared with chemotherapy. Given the modest gains there is a pressing need for predictive biomarkers to better identify patients who would benefit from this targeted therapy. We used a multiplex protein assay to determine the tumor expression levels of the proangiogenic proteins IL-6, IL-8, bFGF, PDGF-BB and VEGF-A in formalin-fixed paraffin-embedded tumors from the MAX clinical trial patients with available tissue samples. Patients were dichotomized into "low" vs. "high" expression subgroups based on median baseline levels to correlate with objective response rate (ORR), progression-free survival (PFS) and overall survival (OS). "Low" tumor VEGF-A level was predictive of better ORR for bevacizumab [ORR (low) 53% vs. (high) 19%, interaction p = 0.03] but not for PFS [hazard ratio, HR (low) 0.73 vs. (high) 0.62, interaction p = 0.68] in the comparison of capecitabine (C) versus C and bevacizumab (CB) and CB plus mitomycin (M). When analyzed as a dichotomized variable, "high" VEGF-A was prognostic for shorter PFS (unadjusted HR 1.34, p = 0.06; adjusted HR 1.55, p = 0.008). The other four proteins were neither predictive of bevacizumab benefits nor prognostic for ORR, PFS or OS. "Low" tumor VEGF-A was associated with longer PFS after adjustment for other baseline factors. Proangiogenic proteins were not predictive of benefit with bevacizumab for PFS.

A proangiogenic signature is revealed in FGF-mediated bevacizumab-resistant head and neck squamous cell carcinoma

Resistance to antiangiogenic therapies is a critical problem that has limited the utility of antiangiogenic agents in clinical settings. However, the molecular mechanisms underlying this resistance have yet to be fully elucidated. In this study, we established a novel xenograft model of acquired resistance to bevacizumab. To identify molecular changes initiated by the tumor cells, we performed human-specific microarray analysis on bevacizumab-sensitive and -resistant tumors. Efficiency analysis identified 150 genes upregulated and 31 genes downregulated in the resistant tumors. Among angiogenesis-related genes, we found upregulation of fibroblast growth factor-2 (FGF2) and fibroblast growth factor receptor-3 (FGFR3) in the resistant tumors. Inhibition of the FGFR in the resistant tumors led to the restoration of sensitivity to bevacizumab. Furthermore, increased FGF2 production in the resistant cells was found to be mediated by overexpression of upstream genes phospholipase C (PLCg2), frizzled receptor-4 (FZD4), chemokine [C-X3-C motif] (CX3CL1), and chemokine [C-C motif] ligand 5 (CCL5) via extracellular signal-regulated kinase (ERK). In summary, our work has identified an upregulation of a proangiogenic signature in bevacizumab-refractory HNSCC tumors that converges on ERK signaling to upregulate FGF2, which then mediates evasion of anti-VEGF therapy. These findings provide a new strategy on how to enhance the therapeutic efficacy of antiangiogenic therapy.

IMPLICATIONS

Novel xenograft model leads to the discovery of FGF as a promising therapeutic target in overcoming the resistance of antiangiogenic therapy in HNSCC.