Anti-invasion, anti-proliferation and anoikis-sensitization activities of lapatinib in nasopharyngeal carcinoma cells

Advances in the Application of Radionuclide-Labeled HER2 Affibody for the Diagnosis and Treatment of Ovarian Cancer

Human epidermal growth factor receptor 2 (HER2) is a highly expressed tumor marker in epithelial ovarian cancer, and its overexpression is considered to be a potential factor of poor prognosis. Therefore, monitoring the expression of HER2 receptor in tumor tissue provides favorable conditions for accurate localization, diagnosis, targeted therapy, and prognosis evaluation of cancer foci. Affibody has the advantages of high affinity, small molecular weight, and stable biochemical properties. The molecular probes of radionuclide-labeled HER2 affibody have recently shown broad application prospects in the diagnosis and treatment of ovarian cancer; the aim is to introduce radionuclides into the cancer foci, display systemic lesions, and kill tumor cells through the radioactivity of the radionuclides. This process seamlessly integrates the diagnosis and treatment of ovarian cancer. Current research and development of new molecular probes of radionuclide-labeled HER2 affibody should focus on overcoming the deficiencies of non-specific uptake in the kidney, bone marrow, liver, and gastrointestinal tract, and on reducing the background of the image to improve image quality. By modifying the amino acid sequence; changing the hydrophilicity, surface charge, and lipid solubility of the affibody molecule; and using different radionuclides, chelating agents, and labeling conditions to optimize the labeling method of molecular probes, the specific uptake of molecular probes at tumor sites will be improved, while reducing radioactive retention in non-target organs and obtaining the best target/non-target value. These measures will enable the clinical use of radionuclide-labeled HER2 affibody molecular probes as soon as possible, providing a new clinical path for tumor-specific diagnosis, targeted therapy, and efficacy evaluation. The purpose of this review is to describe the application of radionuclide-labeled HER2 affibody in the imaging and treatment of ovarian cancer, including its potential clinical value and dilemmas.

Nasopharyngeal Carcinoma: The Role of the EGFR in Epstein-Barr Virus Infection

Epstein-Barr virus (EBV), a type 4 γ herpes virus, is recognized as a causative agent in nasopharyngeal carcinoma (NPC). Incidence of EBV-positive NPC have grown in recent decades along with worse outcomes compared with their EBV-negative counterparts. Latent membrane protein 1 (LMP1), encoded by EBV, induces NPC progression. The epidermal growth factor receptor (EGFR), a member of the ErbB family of receptor tyrosine kinases (RTK), is a driver of tumorigenesis, including for NPC. Little data exist on the relationship between EGFR and EBV-induced NPC. In our initial review, we found that LMP1 promoted the expression of EGFR in NPC in two main ways: the NF-κB pathway and STAT3 activation. On the other hand, EGFR also enhances EBV infection in NPC cells. Moreover, activation of EGFR signalling affects NPC cell proliferation, cell cycle progression, angiogenesis, invasion, and metastasis. Since EGFR promotes tumorigenesis and progression by downstream signalling pathways, causing poor outcomes in NPC patients, EGFR-targeted drugs could be considered a newly developed anti-tumor drug. Here, we summarize the major studies on EBV, EGFR, and LMP1-regulatory EGFR expression and nucleus location in NPC and discuss the clinical efficacy of EGFR-targeted agents in locally advanced NPC (LA NPC) and recurrent or metastatic NPC (R/M NPC) patients.

Lipid-Polymer Hybrid Nanoparticle-Based Combination Treatment with Cisplatin and EGFR/HER2 Receptor-Targeting Afatinib to Enhance the Treatment of Nasopharyngeal Carcinoma

Purpose

Nasopharyngeal carcinoma (NPC) is one of the most prevalent carcinomas among the Cantonese population of South China and Southeast Asia (responsible for 8% of all cancers in China alone). Although concurrent platinum-based chemotherapy and radiotherapy have been successful, metastatic NPC remains difficult to treat, and the failure rate is high.

Methods

Thus, we developed stable lipid–polymer hybrid nanoparticles (NPs) containing cisplatin (CDDP) and afatinib (AFT); these drugs act synergistically to counter NPC. The formulated nanoparticles were subjected to detailed in vitro and in vivo analysis.

Results

We found that CDDP and AFT exhibited synergistic anticancer efficacy at a specific molar ratio. NPs were more effective than a free drug cocktail (a combination) in reducing cell viability, enhancing apoptosis, inhibiting cell migration, and blocking cell cycling. Cell viability after CDDP monotherapy was as high as 85.1%, but CDDP+AFT (1/1 w/w) significantly reduced viability to 39.5%. At 1 µg/mL, AFT/CDDP-loaded lipid–polymer hybrid NPs (ACD-LP) were significantly more cytotoxic than the CDDP+AFT cocktail, indicating the superiority of the NP system.

Conclusion

The NPs significantly delayed tumor growth compared with either CDDP or AFT monotherapy and were not obviously toxic. Overall, the results suggest that AFT/CDDP-loaded lipid–polymer hybrid NPs exhibit great potential as a treatment for NPC.

Advances in targeted therapy mainly based on signal pathways for nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a malignant epithelial carcinoma of the head and neck region which mainly distributes in southern China and Southeast Asia and has a crucial association with the Epstein-Barr virus. Based on epidemiological data, both incidence and mortality of NPC have significantly declined in recent decades grounded on the improvement of living standard and medical level in an endemic region, in particular, with the clinical use of individualized chemotherapy and intensity-modulated radiotherapy (IMRT) which profoundly contributes to the cure rate of NPC patients. To tackle the challenges including local recurrence and distant metastasis in the current NPC treatment, we discussed the implication of using targeted therapy against critical molecules in various signal pathways, and how they synergize with chemoradiotherapy in the NPC treatment. Combination treatment including targeted therapy and IMRT or concurrent chemoradiotherapy is presumably to be future options, which may reduce radiation or chemotherapy toxicities and open new avenues for the improvement of the expected functional outcome for patients with advanced NPC.

Lapatinib sensitivity in nasopharyngeal carcinoma is modulated by SIRT2-mediated FOXO3 deacetylation

Background

Chemoresistance is an obstacle to the successful treatment of nasopharyngeal carcinoma (NPC). Lapatinib is a targeted tyrosine kinase inhibitor therapeutic drug also used to treat NPC, but high doses are often required to achieve a result. To investigate the mechanism for the development of Lapatinib resistance, we characterised a number of NPC cell lines to determine the role of FOXO3 and sirtuins in regulating NPC resistance.

Methods

Sulforhodamine B (SRB) assays, Clonogenic assays, Protein extraction, quantification and western blotting, RT qPCR, Co-immunoprecipitation assay.

Results

To explore novel treatment strategies, we first characterized the Lapatinib-sensitivity of a panel of NPC cell lines by SRB and clonogenic cytotoxic assays and found that the metastatic NPC (C666–1 and 5-8F) cells are highly resistant whereas the poorly metastatic lines (6-10B, TW01 and HK-1) are sensitive to Lapatinib. Western blot analysis of the Lapatinib-sensitive 6-10B and resistant 5-8F NPC cells showed that the expression of phosphorylated/inactive FOXO3 (P-FOXO3;T32), its target FOXM1 and its regulator SIRT2 correlate negatively with Lapatinib response and sensitivity, suggesting that SIRT2 mediates FOXO3 deacetylation to promote Lapatinib resistance. In agreement, clonogenic cytotoxic assays using wild-type and foxo1/3/4^−/− mouse embryonic fibroblasts (MEFs) showed that FOXO1/3/4-deletion significantly attenuates Lapatinib-induced cytotoxicity, confirming that FOXO proteins are essential for mediating Lapatinib response. SRB cell viability assays using chemical SIRT inhibitors (i.e. sirtinol, Ex527, AGK2 and AK1) revealed that all SIRT inhibitors can reduce NPC cell viability, but only the SIRT2-specific inhibitors AK1 and AGK2 further enhance the Lapatinib cytotoxicity. Consistently, clonogenic assays demonstrated that the SIRT2 inhibitors AK1 and AGK2 as well as SIRT2-knockdown increase Lapatinib cytotoxicity further in both the sensitive and resistant NPC cells. Co-immunoprecipitation studies showed that besides Lapatinib treatment, SIRT2-pharmaceutical inhibition and silencing also led to an increase in FOXO3 acetylation. Importantly, SIRT2 inhibition and depletion further enhanced Lapatinib-mediated FOXO3-acetylation in NPC cells.

Conclusion

Collectively, our results suggest the involvement of SIRT2-mediated FOXO3 deacetylation in Lapatinib response and sensitivity, and that SIRT2 can specifically antagonise the cytotoxicity of Lapatinib through mediating FOXO3 deacetylation in both sensitive and resistant NPC cells. The present findings also propose that SIRT2 can be an important biomarker for metastatic and Lapatinib resistant NPC and that targeting the SIRT2-FOXO3 axis may provide novel strategies for treating NPC and for overcoming chemoresistance.

Modeling nasopharyngeal carcinoma in three dimensions

Nasopharyngeal carcinoma (NPC) is a type of cancer endemic in Asia, including Malaysia, Southern China, Hong Kong and Taiwan. Treatment resistance, particularly in recurring cases, remains a challenge. Thus, studies to develop novel therapeutic agents are important. Potential therapeutic compounds may be effectively examined using two-dimensional (2D) cell culture models, three-dimensional (3D) spheroid models or in vivo animal models. The majority of drug assessments for cancers, including for NPC, are currently performed with 2D cell culture models. This model offers economical and high-throughput screening advantages. However, 2D cell culture models cannot recapitulate the architecture and the microenvironment of a tumor. In vivo models may recapitulate certain architectural and microenvironmental conditions of a tumor, however, these are not feasible for the screening of large numbers of compounds. By contrast, 3D spheroid models may be able to recapitulate a physiological microenvironment not observed in 2D cell culture models, in addition to avoiding the impediments of in vivo animal models. Thus, the 3D spheroid model offers a more representative model for the study of NPC growth, invasion and drug response, which may be cost-effective without forgoing quality.

Inhibition of eEF-2 kinase sensitizes human nasopharyngeal carcinoma cells to lapatinib-induced apoptosis through the Src and Erk pathways

Background

Previous studies have reported that eEF-2 kinase is associated with tumour cell sensitivity to certain therapies. In the present study, we investigated the relationship between eEF-2 kinase and lapatinib, a dual inhibitor of EGFR and HER-2, in nasopharyngeal carcinoma (NPC) cells.

Methods

The effect of treatment on the growth and proliferation of NPC cells was measured by three methods: cell counting, crystal violet staining and colony counting. Apoptosis was evaluated by flow cytometry to determine Annexin V-APC/7-AAD and cleaved PARP levels, and the results were further confirmed by Western blot analysis. The expression of eEF-2 kinase and the impacts of different treatments on different signalling pathways were analysed by Western blot analysis.

Results

The expression of eEF-2 kinase was significantly associated with NPC cell sensitivity to lapatinib. Therefore, suppression of this kinase could increase the cytocidal effect of lapatinib, as well as reduce cell viability and colony formation. Furthermore, inhibition of eEF-2 kinase, by either RNA interference (eEF-2 kinase siRNA or shRNA) or pharmacological inhibition (NH125), enhanced lapatinib-induced apoptosis of NPC cells. The results also showed that lapatinib combined with NH125 had a synergistic effect in NPC cells. In addition, mechanistic analyses revealed that downregulation of the ERK1/2 and Src pathways, but not the AKT pathway, was involved in this sensitizing effect.

Conclusions

The results of this study suggest that targeting eEF-2 kinase may improve the efficacy of therapeutic interventions such as lapatinib in NPC cells.

Everolimus enhances cellular cytotoxicity of lapatinib via the eukaryotic elongation factor-2 kinase pathway in nasopharyngeal carcinoma cells

Background

Nasopharyngeal carcinoma (NPC) has a high relapse and metastatic rates; hence, development of new therapeutics is an immediate requirement. Lapatinib and everolimus have been demonstrated to be effective in the treatment of several carcinomas. This preclinical study aimed to investigate the effect and mechanism of lapatinib combined with everolimus on NPC cells.

Methods

The Cell Counting Kit 8 and colony formation assay were used to detect the effect of lapatinib alone or lapatinib combined with everolimus on the growth and proliferation of cells. Apoptosis was tested by flow cytometry and was further confirmed by western blot. The targets of lapatinib and the effects of lapatinib or everolimus on the eukaryotic elongation factor-2 (eEF-2) kinase pathway were analyzed by western blot, which also evaluated autophagy activity.

Results

Lapatinib inhibited the cellular viability and colony formation in NPC cells. At 24–72 h, the average half maximal inhibitory concentration (IC₅₀) values of lapatinib were ranging from 3 to 5 μM. This study further found that lapatinib induced both apoptosis and autophagy in NPC cells, and this autophagic activity was described as type II programmed cell death via an eEF-2 kinase-dependent pathway. In addition, augmentation of lapatinib-induced autophagy by mammalian target of rapamycin (mTOR) inhibitor everolimus enhanced the cytocidal effect of lapatinib in NPC cells via the mTOR/S6 kinase/eEF-2 kinase pathway.

Conclusion

This study reveals that everolimus can sensitize NPC cells to lapatinib by the activation of eEF-2 kinase and provides a potential model of combination therapy.

Antitumor activity of 7RH, a discoidin domain receptor 1 inhibitor, alone or in combination with dasatinib exhibits antitumor effects in nasopharyngeal carcinoma cells

Dysregulation of the discoidin domain receptors (DDRs) has been implicated in the development of numerous types of tumors, including head and neck cancer, and nasopharyngeal, breast, ovarian and esophageal carcinomas. Furthermore, agents that inhibit DDR1 activity are hypothesized to be useful for the treatment of nasopharyngeal carcinoma (NPC). The aim of the present study was to evaluate the effect of the DDR1 inhibitory (3-(2-(pyrazolo(1,5-a)pyrimidin-6-yl)-ethynyl)benzamide compound, 7RH, in NPC cells both in vitro and in vivo, and its effect when used in combination with dasatinib, a SRC family kinase (SFK) inhibitor. The effects of 7RH alone or in combination with dasatinib on cell viability were assessed using MTT assays and apoptosis was detected by flow cytometry. In addition, western blotting was performed to analyze the relative protein expression levels of cell cycle-associated genes in human NPC cell lines (CNE1, CNE2, HONE1 and SUNE1). Cell migration was also assessed using cell adhesion assays. Furthermore, tumor xenografts of CNE2 NPC cells were established in nude mice and the growth inhibitory effects of 7RH treatment alone or in combination with dasatinib were evaluated. Finally, knockdown of DDR1 protein expression was achieved by transfection of CNE2 cells with DDR1-specific small interfering RNA. Treatment with 7RH effectively suppressed the proliferation and induced the apoptosis of NPC cells. In addition, the Janus kinase 1 (JAK1)/signal transducer and activator of transcription (STAT3) signaling pathway was downregulated by 7RH, whereas the activities of the Ras/Raf/mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) and phosphoinositide 3-kinase (PI3K)/AKT signaling pathways were upregulated in response to 7RH treatment. Furthermore, the expression levels of phosphorylated SRC were increased in NPC cells treated with 7RH; thus indicating that SRC exhibits a vital function in the resistance of NPC cells to 7RH via activation of the PI3K/AKT signaling pathway. The results of the present study indicate that DDR1 and SFK inhibition may present a potential therapeutic strategy for patients with NPC.

Transcriptome meta-analysis reveals dysregulated pathways in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a malignant cancer arising from the epithelial surface of the nasopharynx that mostly appears in advanced stages of the disease, leading to a poor prognosis. To date, a number of mRNA profiling investigations on NPC have been reported in order to identify suitable biomarkers for early detection. However, the results may be specific to each study with distinct sample types. In this study, an integrative meta-analysis of NPC transcriptome data was performed to determine dysregulated pathways, potentially leading to identification of molecular markers. Ten independent NPC gene expression profiling microarray datasets, including 135 samples from NPC cell lines, primary cell lines, and tissues were assimilated into a meta-analysis and cross-validation to identify a cohort of genes that were significantly dysregulated in NPC. Bioinformatics analyses of these genes revealed the significant pathways and individual players involving in cellular metabolism, cell cycle regulation, DNA repair, as well as ErbB pathway. Altogether, we propose that dysregulation of these molecular pathways in NPC might play a role in the NPC pathogenesis, providing clues, which could eventually translate into diagnostic and therapeutic approaches.

LMP1 promotes expression of insulin-like growth factor 1 (IGF1) to selectively activate IGF1 receptor and drive cell proliferation

Epstein-Barr Virus (EBV) is a gammaherpesvirus that infects the majority of the human population and is linked to the development of multiple cancers, including nasopharyngeal carcinoma. Latent membrane protein 1 (LMP1) is considered the primary oncoprotein of EBV, and in epithelial cells it induces the expression and activation, or phosphorylation, of the epidermal growth factor receptor kinase. To identify effects on additional kinases, an unbiased screen of receptor tyrosine kinases potentially activated by LMP1 was performed. Using a protein array, it was determined that LMP1 selectively activates insulin-like growth factor 1 receptor (IGF1R). This activation takes place in fibroblast, epithelial, and nasopharyngeal cell lines that express LMP1 stably and transiently. Of note, LMP1 altered the phosphorylation, but not the expression, of IGF1R. The use of LMP1 mutants with defective signaling domains revealed that the C-terminal activating region 2 domain of LMP1 increased the mRNA expression and the secretion of the ligand IGF1, which promoted phosphorylation of IGF1R. IGF1R phosphorylation was dependent upon activation of canonical NF-κB signaling and was suppressed by IκBα and a dominant negative form of TRAF6. Inhibition of IGF1R activation with two small-molecule inhibitors, AG1024 and picropodophyllin (PPP), or with short hairpin RNA (shRNA) directed against IGF1R selectively reduced proliferation, focus formation, and Akt activation in LMP1-positive cells but did not impair LMP1-induced cell migration. Expression of constitutively active Akt rescued cell proliferation in the presence of IGF1R inhibitors. These findings suggest that LMP1-mediated activation of IGF1R contributes to the ability of LMP1 to transform epithelial cells.

IMPORTANCE

EBV is linked to the development of multiple cancers in both lymphoid and epithelial cells, including nasopharyngeal carcinoma. Nasopharyngeal carcinoma is a major cancer that develops in specific populations, with nearly 80,000 new cases reported annually. LMP1 is consistently expressed in early lesions and continues to be detected within 50 to 80% of these cancers at later stages. It is therefore of paramount importance to understand the mechanisms through which LMP1 alters cell growth and contributes to tumorigenesis. This study is the first to determine that LMP1 activates the IGF1R tyrosine kinase by regulating expression of the ligand IGF1. Additionally, the data in this paper reveal that specific targeting of IGF1R selectively impacts LMP1-positive cells. These findings suggest that therapies directed against IGF1R may specifically impair the growth of EBV-infected cells.

ERBB3 as an independent prognostic marker for nasopharyngeal carcinoma

Aim

Although the ERBB proteins have been shown to be associated in many types of human tumours and serve as important cancer therapeutic targets, however, data regarding the expression and clinical relevance of ERBBs in nasopharyngeal carcinoma (NPC) are still conflicting. The aim of this study is to investigate the expression pattern of all ERBB members simultaneously in NPC tissues using immunohistochemistry and determine their clinical relevance.

Methods

The expression of all members of ERBB proteins was evaluated using immunohistochemistry on 82 NPC tissue samples. Relationship between the ERBB protein expression, clinicopathological parameters and patient outcome was assessed using univariate and multivariate analyses.

Results

We found that ERBB1, ERBB2 and ERBB3 were strongly expressed in the normal nasopharyngeal epithelial cells. A marked reduction of ERBB1 and ERBB2 expression in NPC was observed compared with the non-cancerous tissues. 76 of 82 (92.7%) cases were ERBB3-positive, while ERBB4 was not expressed in both normal and NPC. The univariate log-rank analysis showed that regional lymph node metastasis, systemic metastasis, recurrence and ERBB3 expression were associated with patient survival. The ERBB3 expression was not correlated to other clinicopathological factors. Furthermore, multivariate analysis revealed that ERBB3 expression was an independent prognostic factor influencing patient survival.

Conclusions

Our results suggested that the expression of ERBB3 is associated with patient survival and could serve as a novel and valuable predictor for prognostic evaluation of patients with NPC.

Gene expression changes as markers of early lapatinib response in a panel of breast cancer cell lines

Background

Lapatinib, a tyrosine kinase inhibitor of HER2 and EGFR and is approved, in combination with capecitabine, for the treatment of trastuzumab-refractory metastatic breast cancer. In order to establish a possible gene expression response to lapatinib, a panel of breast cancer cell lines with varying sensitivity to lapatinib were analysed using a combination of microarray and qPCR profiling.

Methods

Co-inertia analysis (CIA), a data integration technique, was used to identify transcription factors associated with the lapatinib response on a previously published dataset of 96 microarrays. RNA was extracted from BT474, SKBR3, EFM192A, HCC1954, MDAMB453 and MDAMB231 breast cancer cell lines displaying a range of lapatinib sensitivities and HER2 expression treated with 1 μM of lapatinib for 12 hours and quantified using Taqman RT-PCR. A fold change ≥ ± 2 was considered significant.

Results

A list of 421 differentially-expressed genes and 8 transcription factors (TFs) whose potential regulatory impact was inferred in silico, were identified as associated with lapatinib response. From this group, a panel of 27 genes (including the 8 TFs) were selected for qPCR validation. 5 genes were determined to be significantly differentially expressed following the 12 hr treatment of 1 μM lapatinib across all six cell lines. Furthermore, the expression of 4 of these genes (RB1CC1, FOXO3A, NR3C1 and ERBB3) was directly correlated with the degree of sensitivity of the cell line to lapatinib and their expression was observed to “switch” from up-regulated to down-regulated when the cell lines were arranged in a lapatinib-sensitive to insensitive order. These included the novel lapatinib response-associated genes RB1CC1 and NR3C1. Additionally, Cyclin D1 (CCND1), a common regulator of the other four proteins, was also demonstrated to observe a proportional response to lapatinib exposure.

Conclusions

A panel of 5 genes were determined to be differentially expressed in response to lapatinib at the 12 hour time point examined. The expression of these 5 genes correlated directly with lapatinib sensitivity. We propose that the gene expression profile may represent both an early measure of the likelihood of sensitivity and the level of response to lapatinib and may therefore have application in early response detection.

Momordica Charantia lectin, a type II ribosome inactivating protein, exhibits antitumor activity toward human nasopharyngeal carcinoma cells in vitro and in vivo

The incidence of nasopharyngeal carcinoma (NPC) remains high in endemic regions, including southern China, northern Africa, and North America. One of the promising therapeutic approaches on NPC is drug screening from natural products, such as components from traditional Chinese medicine. In this study, the antitumor activity of Momordica charantia lectin (MCL), a type II ribosome inactivating protein from bitter gourd, on NPC was investigated. MCL evinced potent cytotoxicity toward NPC CNE-1 (IC(50) = 6.9) and CNE-2 (IC(50) = 7.4) cells but minimally affected normal NP 69 cells. Further investigation disclosed that MCL induced apoptosis, DNA fragmentation, G(1)-phase arrest, and mitochondrial injury in both types of NPC cells. The reduction of cyclin D1 and phosphoretinoblastoma (Rb) protein expression contributed to arrest at G(1)-phase of the cell cycle. These events were associated with regulation of mitogen-activated protein kinases (MAPK; including p38 MAPK, JNK, and ERK) phosphorylation and promoted downstream nitric oxide (NO) production. Concurrent administration of the p38 MAPK inhibitor SB-203580 significantly diminished NO production and lethality of MCL toward NPC cells. Further studies revealed that MCL increased cytochrome c release into the cytosol, activated caspases-8, -9, and -3, and enhanced production of cleaved PARP, subsequently leading to DNA fragmentation and apoptosis. Finally, an intraperitoneal injection of MCL (1.0 mg/kg/d) led to an average of 45% remission of NPC xenograft tumors subcutaneously inoculated in nude mice. This is the first article that unveils the potential of a type II RIP, MCL, for prevention and therapy of NPC.