Pharyngeal Cancer Cells Research Articles

THE CYTOTOXIC EFFECT OF BENZOIC ACID ON TEN DIFFERENT CANCER CELL LINES

Cancer, having numerous types, is among the most dangerous and complex chronic diseases in the world affecting the wellbeing of humans, society and economy. The exploration and reassessment of effective chemicals, compounds, and natural products as potential agents for alleviating the adverse effects of cancer and its related symptoms continue on a global scale. This process involves an initial evaluation of the cytotoxic activities of potential drug candidates or treatment regimens on diverse cancer cell types in an ex vivo context. Benzoic acid (BA), an aromatic carboxylic acid that is widely available and used in the food industry, is one of the phenolic acids that may bear considerable anti-cancer potential. It is useful to find out the comparable effect of BA on various cancer types. Therefore, in this study, we tested the cytotoxicity of BA using MTT assay, on a number of ten different cancer cell lines and one normal cell type, namely prostate cancer (PC3), cervical cancer (HeLA), liver cancer (HUH7), colon cancer (CaCO2, HT29, SW48), bone cancer (MG63 and A673), pharyngeal cancer (2A3), lung cancer (CRM612) and kidney epithelial control cell line (Phoenix), respectively. IC50 (µg/ml) values after 48 and 72-hour exposure to BA were found to differ between 85.54±3.17 to 670.6±43.26, while the IC values for the control cell line Phoenix were 410.54±32.29 and 231.16±25.25, respectively. Taking into account of statistical evaluation of the IC50 values for BA on 11 cell types, we suggest that the molecular and omics approaches can be implemented in more details in order to find cellular and biochemical targets of BA as well as elucidating molecular mode of action, especially starting with the cancer cell lines of MG63, CRM612 and A673, in which the IC50 levels are relatively the lowest compared to those of the control cell line.

A combination of all-trans retinoic acid derivative and COX-2 inhibitor has anticancer effects in human pharyngeal carcinoma cells

Backgrounds and aimsCarcinogenesis is characterized by an unlimited growth of cells exacerbated by Cox-2 overexpression. Cox-2 inhibitors have been proven effective in preventing and treating tumors. In our previous studies, we found that 4-Amino-2-Trifluoromethylphenyl Retinate (ATPR) induces cell apoptosis and inhibits cell proliferation to exhibit anti-cancer properties. The use of ATRA as well as Cox-2 inhibitors in clinical settings can cause adverse reactions. It is unknown what the effects and mechanisms of co-administration of ATPR and Cox-2 inhibitors are. ResultsA combination of ATPR and Cox-2 inhibitors, Celecoxib, inhibited pharyngeal cancer cell proliferation in vitro and induced apoptosis. The cell cycle was arrested at G0/G1 by activating P53 and CDNA1. By activating MAPK/JNK pathways, ATPR and Celecoxib led to intrinsic and extrinsic apoptosis in pharyngeal cancer cells. ATPR/Celecoxib combined treatment suppressed tumor growth in the pharyngeal cancer cell-derived xenograft mouse model by increasing the number of apoptotic cells. The expression of the RARA and PTGS2 genes was significantly increased in tumor tissue compared to non-tumor tissue in the clinical analysis of the head and neck squamous cell carcinoma dataset. An association was found between this and the level of intrinsic apoptotic signals. Furthermore, a survival analysis conducted over a period of five years indicated that higher levels of RARA expression were associated with a better clinical outcome. ConclusionATPR and celecoxib inhibit the proliferation of cancer cells as well as induce apoptosis. Co-administration of ATPR and Cox-2 inhibitors has the potential to be a novel treatment plan for cancer.

Investigating the vital effect of gold nanoparticles prepared by thyme extract by green synthesis method on FaDu pharyngeal cancer cell line

Investigating the vital effect of gold nanoparticles prepared by thyme extract by green synthesis method on FaDu pharyngeal cancer cell line

124I-labeled anti-CD147 antibody for noninvasive detection of CD147-positive pan-cancers: construction and preclinical studies.

Extracellular matrix metalloproteinase inducer CD147 is a glycoprotein on the cell surface. There is minimal expression of CD147 in normal epithelial and fetal tissues, but it is highly expressed in a number of aggressive tumors. CD147 has been implicated in pan-cancer immunity and progression. With the development of CD147-targeting therapeutic strategy, accurate detection of CD147 expression in tumors and its changes during the therapy is necessary. In this study we constructed a novel radiotracer by labeling the anti-CD147 mAb with radionuclide 124/125I (124/125I-anti-CD147) for noninvasive detection of CD147 expression in pan-cancers, and characterized its physicochemical properties, affinity, metabolic characteristics, biodistribution and immunoPET imaging with 124I-IgG and 18F-FDG as controls. By examining the expression of CD147 in cancer cell lines, we found high CD147 expression in colon cancer cells LS174T, FADU human pharyngeal squamous cancer cells and 22RV1 human prostate cancer cells, and low expression of CD147 in human pancreatic cancer cells ASPC1 and human gastric cancer cells BGC823. 124/125I-anti-CD147 was prepared using N-bromine succinimide (NBS) as oxidant and purified by PD-10 column. Its radiochemical purity (RCP) was over 99% and maintained over 85% in saline or 5% human serum albumin (HSA) for more than 7 d; the RCP of 125I-anti-CD147 in blood was over 90% at 3 h post injection (p.i.) in healthy mice. The Kd value of 125I-anti-CD147 to CD147 protein was 6.344 nM, while that of 125I-IgG was over 100 nM. 125I-anti-CD147 showed much greater uptake in CD147 high-expression cancer cells compared to CD147 low-expression cancer cells. After intravenous injection in healthy mice, 125I-anti-CD147 showed high initial uptake in blood pool and liver, the uptake was decreased with time. The biological half-life of distribution and clearance phases in healthy mice were 0.63 h and 19.60 h, respectively. The effective dose of 124I-anti-CD147 was estimated as 0.104 mSv/MBq. We conducted immunoPET imaging in tumor-bearing mice, and demonstrated a significantly higher tumor-to-muscle ratio of 124I-anti-CD147 compared to that of 124I-IgG and 18F-FDG in CD147 (+) tumors. The expression levels of CD147 in cells and tumors were positively correlated with the maximum standardized uptake value (SUVmax) (P < 0.01). In conclusion, 124/125I-anti-CD147 displays high affinity to CD147, and represents potential for the imaging of CD147-positive tumors. The development of 124I-anti-CD147 may provide new insights into the regulation of tumor microenvironment and formulation of precision diagnosis and treatment programs for tumors.

Chemical Characterization of Different Extracts of Justicia secunda Vahl and Determination of Their Anti-Oxidant, Anti-Enzymatic, Anti-Viral, and Cytotoxic Properties.

Justicia secunda Vahl. is a traditional medicinal plant in tropical regions, including West Africa. The present study examined the chemical profiles and biological properties of J. secunda extracts obtained with different solvents (dichloromethane, ethyl acetate, methanolic and aqueous: macerated and infused). Chemical components were characterized by liquid chromatography-mass spectrometry (LC-MS), and over 50 compounds were identified, including flavonoids, phenolic acids, and alkaloids. Antioxidant, enzyme inhibitory, cytotoxic, and antiviral properties were selected as biological properties. Total phenolic and flavonoid contents in methanol (58.07 mg gallic acid equivalent (GAE)/g and 13.07 mg rutin equivalent (RE)/g) and water (infused) (36.34 mg GAE/g and 8.52 mg RE/g) were higher than in other extracts. Consistent with the levels of total bioactive components, the methanol and water extracts exhibited stronger antioxidant abilities. However, the dichloromethane and ethyl acetate extracts were more active on α-amylase and α-glucosidase than other extracts. Aqueous extracts exerted selective anticancer properties toward human pharyngeal cancer cell lines, whereas the methanolic extract decreased the human herpesvirus type-1 (HHV-1) infectious titer by 2.16 log and the viral load by 1.21 log. Overall, J. secunda could be considered a multifunctional bioactive raw material in the preparation of potent applications to manage diseases related to oxidative stress, including cancer, diabetes, and Alzheimer's.

LSD1 silencing inhibits the proliferation, migration, invasion, and epithelial-to-mesenchymal transition of hypopharyngeal cancer cells by inducing autophagy and pyroptosis.

Hypopharyngeal cancer is a subtype of the head and neck malignancies. We aimed to explore the role of lysine-specific demethylase 1 (LSD1/KDM1A) in the progression of hypopharyngeal cancer and to identify the potential mechanisms. First, LSD1 expression in head and neck squamous cell carcinoma (HNSCC) tissues and the correlation between LSD1 and the stage of HNSC were analyzed by the University of ALabama at Birmingham CANcer data analysis Portal (UALCAN). Following LSD1 silencing, proliferation of pharyngeal cancer cell line FaDu cells was evaluated by cell counting kit-8 and colony formation assays. Wounding healing and transwell assays were used to measure the capacities of migration and invasion. In addition, expression of proteins related to epithelial-to-mesenchymal transition (EMT), autophagy, and pyroptosis was tested by Western blot analysis or immunofluorescence. After treatment with autophagy inhibitor 3-methyladenine (3-MA) or NLR family pyrin domain containing 3 (NLRP3) inhibitor MCC950, the malignant biological properties were measured again. High LSD1 expression was observed in HNSC tissues, which was correlated with stage. LSD1 knockdown significantly suppressed the proliferation, migration, invasion, and EMT of hypopharyngeal cancer cells. Moreover, autophagy and pyroptosis were induced by LSD1 depletion, observed by the enhanced fluorescence intensity of LC3, gasdermin-D (GSDMD)-N, and apoptosis-associated speck-like protein containing a CARD (ASC), accompanied by upregulated expression of LC3II/LC3I, Beclin-1, NLRP3, cleaved-caspase 1, ASC, interleukin (IL)-1β, and IL-18 and downregulated expression of p62. Importantly, 3-MA or MCC950 addition obviously reversed the inhibitory effects of LSD1 silencing on the proliferation, migration, invasion, and EMT of hypopharyngeal cancer cells. To sum up, LSD1 silencing could restrain the progression of hypopharyngeal cancer cells by inducing autophagy and pyroptosis.

The In Vitro Impact of Two Scaffold-Type Structure Dental Ceramics on the Viability, Morphology, and Cellular Migration of Pharyngeal Cancer Cells

There is a growing trend with respect to the use of ceramic materials in dental practice. With an increase in the number of cases of head and neck cancer, the use of dental implants in these patients is subject to controversy. Consequently, the purpose of the present study was to evaluate the impact of two ceramic materials on the viability, proliferation, migration, and structure of the cytoskeleton and nuclei of pharyngeal cancer cells. Therefore, samples of the two ceramic were immersed in artificial saliva with three different pH values in order to better simulate the natural biological environment. A 21-day immersion period was followed by testing of the saliva on pharyngeal cancer cell line Detroit-562 for its viability, morphology, and migration, as well as its effects on the nucleus and cytoskeleton. The results of the study after stimulation of Detroit-562 cells for 72 h with the three types of artificial saliva in which the ceramic materials were immersed indicated the following: (i) viability of cells did not change significantly, with the percentage of viable cells not falling below 90%; (ii) no morphological changes were recorded, with the shape and number of cells being similar to that of the control cells; (iii) the scratch assay method indicated that the two types of ceramics do not stimulate cell migration; and (iv) fluorescence immunocytochemistry revealed that both the nucleus and the cytoskeleton distributions were unaltered, as they were observed in unstimulated cells. The preliminary results of the study indicate that the investigated ceramic materials did not interact unfavorably with tumor cells when immersed in artificial saliva, thereby supporting the possibility of their safe use in cancer patients.

INVESTIGATION OF CIRCULAR RNAs AS BIOMARKERS IN HEAD AND NECK CANCER CELLS AND THE EFFECTS OF RADIOTHERAPY ON CIRCULAR RNAs

Objective: The head and neck squamous cell carcinoma (HNSCC) is the sixth most common type of cancer worldwide and the 5-year survival rate of patients is by 40-50 %. Radiotherapy is one of the important treatments for HNSCC. circRNAs, which are much more stabil than other RNAs because of their circular structure, have the potential to be a biomarker for all types of cancer. Therefore, the alterations of circRNAs expression in HNSCC cells and after irradiation was investigated. Methods: Pharyngeal cancer (Detroit-562) and healthy fibroblast (WI-38) cell lines were used. After appropriate irradiation dose for Detroit-562 cells was determined by colony formation assay, Detroit-562 cells were irradiated with 4 grays. The expression levels of 122 circRNA molecules in all groups were examined by RT-qPCR. The results were evaluated using CircNet and TCGA platforms. Results: In this study, 60 circRNAs were not expressed in any cell line, whereas 62 were found to be expressed in at least one of the groups, including irradiated Detroit-562, Detroit-562, and WI-38 cell lines. Among them, seven circRNAs were detected in all groups and expressed higher in Detroit-562 than two groups. Interestingly, these circRNAs were significantly decreased in irradiated group, exhibiting similar expression levels with healthy group. Bioinformatics analyses showed that the host genes of these circRNAs was also higher expressed in HNSCC tissue. Conclusions: Differential expression of circRNAs in cancers and changes with treatment revealed that they could be potential diagnostic and monitoring biomarkers in cancer. However, further studies need in this regard.

In vitro radiosensitization by eribulin in human cancer cell lines.

BackgroundThe objective was to to determine the radiosensitizing properties of eribulin and the potential mechanisms of radiosensitization in cervical (HeLa) and pharyngeal (FaDu) cancer cell lines.Materials and methodsCytotoxicity was evaluated by the crystal violet method. The 10% and 50% inhibitory concentration (IC10, IC50) for 24-hour drug exposure were determined. The surviving fraction at 2 Gy (SF2) and the sensitizer enhancement ratio (SER) were calculated from radiation cell survival curves in the presence or absence of eribulin. Combination index (CI) was calculated to determine if there is a true synergistic interaction between eribulin and irradiation. Cell cycle changes were assessed by propidium iodide staining and flow cytometry. Apoptotic cells were detected by annexin V and TUNEL-assay.ResultsMean IC50s and IC10s were 1.58 nM and 0.7 nM and 0.7 nM and 0.27 nM for HeLa and FaDu cells, respectively. Radiosensitization was observed in both lines with a SER up to 2.71 and 2.32 for HeLa and FaDu cells, respectively. A true synergistic effect was showed with a CI of 0.82 and 0.76 for HeLa and FaDu cells, respectively. Eribulin induced significant G2/M cell arrest and marked apoptosis. Irradiation combined with 3 nM eribulin increased the apoptotic response to radiation in Hela cells.ConclusionEribulin shows a true in vitro radiosensitizing effect in HeLa and FaDu cells by inducing significant G2/M phase arrest. In HeLa, the enhancement radiation-induced apoptosis could be an additional mechanism of radiosensitization. Further studies are needed to evaluate the clinical benefits of concurrent eribulin and radiotherapy as a novel therapeutic strategy for cancer.

THE EFFECTS OF SULINDAC ON CELL VIABILITY, CELL CYCLE AND ANJIOGENEZİS IN PHARYNGEAL CANCER CELL

Objective: The present study aimed to investigate the effects of Sulindac on cell viability, cell cycle and angiogenesis in pharyngeal cancer cell lines (FaDu). Methods: FaDu cells were incubated in a medium in a 5% CO2 incubator at 37°C, after which they were proliferated and passaged. IC50 concentration was used to determine the Sulindac dose. Cells were analyzed for cell viability, cell count and cell cycle after Sulindac administration. Immunohistochemistry (vascular endothelial growth factor receptor 2) and western blot (A disintegrin and metalloproteinase with thrombospondin-like motifs 1-ADAMTS1) analyses were used for angiogenesis assessment. Results: Cell viability decreased in pharyngeal cancer cells after Sulindac administration. In addition, FaDU cells were arrested in the G2/M phase. Sulindac was found to slightly increase vascular endothelial growth factor receptor 2 (VEGF-R2) and decrease ADAMTS1 levels in pharyngeal cancer cells. Conclusion: Sulindac showed positive results on cell proliferation in the treatment of pharyngeal cancer cells. However, it could cause a slight increase in angiogenesis.

Omethoate induces pharyngeal cancer cell proliferation and G1/S cell cycle progression by activation of Akt/GSK-3β/cyclin D1 signaling pathway

Omethoate is a broad category of organophosphorous pesticides (OPs) and has toxic effects on human health under long-term, low-dose exposure. However, the role of omethoate in cancer development remains elusive. The incidence of global head and neck squamous cell carcinomas (HNSCC) has markedly increased in recent years. Thus, we examined whether omethoate induced the proliferation of FaDu cells (a cell line of HNSCC) and if so, what the underlying mechanism was. The study revealed that omethoate induced FaDu cell growth in a dose- and time-dependent manner. Omethoate stimulated FaDu cell proliferation was mainly due to enhancing the G1 to S phase transition by flow cytometry analysis. We also found that omethoate up-regulated cyclin D1, a key gene controlling the G1-S transition. Furthermore, we showed that omethoate was capable of activating the Akt/GSK-3β signaling pathway. Blockage of Akt by siRNA or small molecule inhibitor significantly suppressed omethoate-induced cyclin D1 expression and cell proliferation. Collectively, these findings demonstrated for the first time that omethoate could induce the pharyngeal cancer cell proliferation by activation of the Akt/GSK-3β/cyclin D1 signaling pathway.

Non-viral suicide gene therapy in cervical, oral and pharyngeal carcinoma cells with CMV- and EEV-plasmids.

Cervical cancer is the third most common cause of cancer in women. The 5-year survival rate in oropharyngeal squamous cell carcinomas is approximately 50% and this rate has not improved in recent decades. These cancers are accessible to direct intervention. We examined the ability of a highly efficient non-viral vector, TransfeX (ATCC, Manassas, VA, USA), to deliver the suicide gene HSV-tk to cervical, oral and pharyngeal cancer cells and to induce cytotoxicity following the administration of the prodrug, ganciclovir. HeLa cervical carcinoma, HSC-3 and H357 oral squamous cell carcinoma and FaDu pharyngeal carcinoma cells were transfected with cytomegalovirus (CMV)- or enhanced episomal vector (EEV)-driven HSV-tk plasmids and treated with ganciclovir for 24-120h. Cell viability was assessed by Alamar blue. The viability of HeLa cells was reduced to only 30-40%, despite the very high levels of transgene expression. By contrast, the viability of HSC-3 cells was reduced to 10%, although transgene expression was 18-fold lower than that in HeLa cells. An approximately five-fold higher transgene expression was obtained with the EEV-plasmid than from the CMV-plasmid. Nevertheless, HeLa cell viability after suicide gene+ganciclovir treatment was reduced by only 35% compared to 70% with the CMV-plasmid. For HSC-3 cells, the reduction was 40% for the EEV- and 80% for the CMV-plasmid. The lower efficiency of transfection with the EEV-plasmid may explain the lower cytotoxicity. TransfeX-mediated gene delivery to cervical, pharyngeal and oral cancer cells may be used for suicide gene therapy. The levels of transgene expression, however, do not translate directly to cytotoxicity.

E26 Transformation-Specific Transcription Factor ETS2 as an Oncogene Promotes the Progression of Hypopharyngeal Cancer.

The E26 transformation-specific (ETS) family is one of the largest families of transcription factors. Upon activation by MAPK pathway, ETS participates in cell proliferation, differentiation, migration, apoptosis, and metastasis. However, the mechanism by which ETS is deregulated in cancer is unclear. In this study, the authors investigated the role of ETS factor, ETS2, in hypopharyngeal cancer pathogenesis in hypopharyngeal cancer tissues (N = 20) and corresponding non-neoplastic tissues (N = 20). The results showed that expression of ETS2 was increased in cancer tissues as compared with the expression in corresponding non-neoplastic tissues. Analysis of clinicopathological characteristics showed that increased level of ETS2 is associated with III-IV tumor node metastasis stage and lymph node metastasis. In addition, knockdown of ETS2 by siRNA in pharyngeal cancer cell line, FaDu, significantly decreased cell's vitality and colony-forming ability by inducing caspase-3-dependent apoptosis and cell cycle arrest. Furthermore, inhibition of ETS2 could abrogate the migration, invasion, and transforming growth factor-β-induced epithelial mesenchymal transition through the upregulation of E-cadherin, zona occludens protein-1, together with downregulation of vimentin and α-sooth muscle actin. These functions of ETS2 could be associated with the activation of MAPK/p38/ERK/JNK signals. Taken together, the authors opined that ETS2 functions as an oncogene and plays a key role in the progression of hypopharyngeal cancer.

Induction of Mitotic Delay in Pharyngeal and Nasopharyngeal Carcinoma Cells Using an Aqueous Extract of Ajuga bracteosa.

Nasopharyngeal carcinoma (NPC) is a common cancer in Southeast Asia, for which radiotherapy and/or chemotherapy are the primary treatment methods. Many herbs are known to have potential uses in chemotherapy; however, the mechanisms underlying the observed antitumor activity of Ajuga bracteosa (AB) against NPC remain unclear. We explored the antitumor effects of AB, which was shown specifically to induce mitotic delay in pharyngeal (Detroit 562) and nasopharyngeal (Hone-1) cancer cells. Proliferation of cancer cells after exposure to aqueous extract of A. bracteosa (AEAB) was assessed using the MTT assay. DNA content and cell cycle arrest induction were analyzed using flow cytometry. The expression of checkpoint kinase 2 (CHK2), cell division control protein 2 (CDC2), and cyclin B1 was investigated using qRT-PCR and Western blot analysis. Results indicated the inhibition of cancer cell growth following exposure to AEAB. In addition, AEAB induced the accumulation of G2/M-phase cells in cancer cell through the disassociation of CDC2/cyclin B1 complex. Our findings suggested that, in addition to the known effects of AEAB in NPC prevention, it may have antitumor activities against NPC cells. In conclusion, AEAB inhibits the growth of and induces mitotic delay in cancer cells, supporting its use as an anticancer agent.

Toll-like receptor 3 stimulation triggers metabolic reprogramming in pharyngeal cancer cell line through Myc, MAPK, and HIF.

Toll-like receptor 3 (TLR3) has a dual role in cancer; its activation can trigger apoptosis as well as stimulate cancer cell survival, proliferation, and progression. We have shown here that TLR3 activation can induce metabolic reprogramming in a pharyngeal cancer cell line, leading to increased aerobic glycolysis, cell migration, elevated levels of reactive oxidative species (ROS), and decreased anti-oxidative response. Key proteins in these signaling pathways are heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1), pyruvate kinase M2 (PKM2), and CD44 variants, which were over-expressed after TLR3 stimulation. TLR3 activation also induced upregulation of different genes involved in cancer progression (VEGF, MMP9, uPAR) and enzymes involved in glycolytic pathway. Most of the observed effects were Myc-dependent; however, some of them were also connected with MAPK and HIF signaling pathways. Since TLR3 agonists are being investigated as potential novel cancer therapy adjuvants and apoptosis inducers, alone or in combination with other therapeutic options, data presented here suggest extreme caution before their introduction into clinical practice. The fact that TLR3 ligands [poly(I:C) and poly(A:U)] can also aid cancer survival and progression, through induction of metabolic reprogramming, emphasizes the need to investigate this particular topic. Our data suggest that the combination of TLR3 ligands with Myc or MAPK inhibitors may be a way to neutralize their undesirable effects while enhancing their anti-tumor effect. © 2016 Wiley Periodicals, Inc.

Abstract B72: Combination therapy by Toll-like receptor 3 activation and chemotherapeutics synergistically induces cancer cell death.

Abstract Toll-like receptors (TLRs) recognize molecular motifs of microbial origin and initiate innate immune response. TLR agonists are already being used in clinical studies because of their ability to induce apoptosis and activate the immune system. We have previously shown that TLR3 activation by synthetic dsRNA [poly (I:C)] in the pharyngeal cancer cell line Detroit 562 induced caspase-dependent apoptosis. Additionally, when combined with chemotherapeutics this treatment acts synergistically by enhancing cancer cell death. In this study we tried to decipher the mechanism of poly (I:C) and chemotherapeutics synergy. Cell survival was determined by using cytotoxicity assay and colony formation assay while protein expression was obtained by western blot. We demonstrated that combination of poly (I:C) and cisplatin is TLR3-dependent while methotrexate and hydroxyurea act through other dsRNA receptors (RIG-I and MDA5). Subsequently, we showed that poly (I:C) had more complex effects on Detroit 562 cells than previously thought: while it induces pro-apoptotic events it also triggers anti-apoptotic mechanisms, for example an increase in the expression of c-IAP2. Combined treatment by poly (I:C) and c-IAP inhibitor significantly decreased cell survival even at low concentrations. However, poly (A:U), which stimulates only TLR3 and not other dsRNA receptors, when combined with c-IAP inhibitor induced cell death only at high concentrations suggesting that RIG-I and MDA5 are also involved. Conversely, the combination of c-IAP inhibitors with poly (I:C) and chemotherapeutics did not result in a stronger cytotoxic effect against malignant cells. One explanation seems to be the fact that cisplatin abrogated c-IAP2 expression induced by poly (I:C) in the Detroit 262 cells thus shifting the balance towards apoptosis. Our conclusion is that future investigations should explore combinations of poly (I:C) with either cisplatin or c-IAP inhibitors. When we used laryngeal cell line SQ20B stably transfected with inducible shRNA for TLR3, we confirmed that synergistic effect of poly (A:U) and cisplatin on cell death is TLR3-dependent. Additionally, as SQ20B is radiation resistant cell line, we have shown here that they can be sensitized to radiotherapy by treatment with poly (I:C). In conclusion, synthetic dsRNAs like poly (I:C) have the potential to help overcoming the resistance of some human malignant cells to classical modalities of radiotherapy and chemotherapy. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B72. Citation Format: Tanja Matijevic Glavan, Benjamin Verillaud, Pierre Busson, Jasminka Pavelic. Combination therapy by Toll-like receptor 3 activation and chemotherapeutics synergistically induces cancer cell death. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B72.

Antitumor Activity from the Combined Application of Poly(I:C) and Chemotherapeutics in Human Metastatic Pharyngeal Cell Lines

Background: Toll-like receptor 3 (TLR3) activation in tumor cells induces apoptosis. We investigated the effect of TLR3 ligand (poly(I:C)) in combination with chemotherapeutics applied to human pharyngeal carcinoma cells as a possible antitumor therapy. Methods:Human pharyngeal cancer cell lines were studied (FaDu and Detroit 562). Cytotoxicity assays and apoptosis assays (annexin V staining and caspase 3/7 activity measurements) were used to investigate the cytotoxic effects. By using TLR3 siRNA we confirmed that the observed effect is TLR3-dependent. Results: We found that the combined application of poly(I:C) and chemotherapeutics (cisPt, HU, 5-FU and MTX) has a stronger inhibitory effect on cell growth in tumor cells expressing functional TLR3 as compared with a single treatment. This is a result of TLR3-dependent apoptosis. Conclusion: Our study showed that a combined application of the two agents already being used in tumor therapy could lower the necessary dosage of chemotherapeutics, leading to fewer side effects.

Adhesion molecule periplakin is involved in cellular movement and attachment in pharyngeal squamous cancer cells

BackgroundWe previously reported that periplakin (PPL) is downregulated in human esophageal cancer tissues compared to the adjacent non-cancer epithelium. Thus PPL could be a useful marker for detection of early esophageal cancer and evaluation of tumor progression, but largely remains unknown in this field. To investigate PPL involvement in carcinogenesis, tumor progression, cellular movement or attachment activity, siRNAs against PPL were transfected into pharyngeal squamous cancer cell lines and their effects on cellular behaviours were examined.ResultsPPL knockdown appeared to decrease tumor cell growth together with G2/M phase accumulation in cells attached to a culture dish. However, the extent of cell growth suppression, evaluated by the number of cells attached to the culture dish, was too distinctive to be explained only by cell cycle delay. Importantly, PPL knockdown suppressed cellular movement and attachment to the culture dish accompanied by decreased pAktSer473 phosphorylation. Additionally, LY294002, a PI3K inhibitor that dephosphorylates pAktSer473, significantly suppressed D562 cell migration. Thus PPL potentially engages in cellular movement al least partly via the PI3K/Akt axis.ConclusionsPPL knockdown is related to reduced cellular movement and attachment activity in association with PI3K/Akt axis suppression, rather than malignant progression in pharyngeal cancer cells.

Alcohol Consumption and Cancer Risk

This review focuses on selected aspects of the relation between alcohol consumption and cancer risk. Heavy alcohol consumption (i.e., ≥4 drinks/day) is significantly associated with an increased risk of about 5-fold for oral and pharyngeal cancer and esophageal squamous cell carcinoma, 2.5-fold for laryngeal cancer, 50% for colorectal and breast cancers, and 30% for pancreatic cancer. These estimates are based on a large number of epidemiological studies and are generally consistent across strata of several covariates. The evidence suggests that at low doses of alcohol consumption (i.e., ≤1 drink/day) the risk is also increased by about 20% for oral and pharyngeal cancer and 30% for esophageal squamous cell carcinoma. Thus, for these sites there is little evidence of a threshold effect. While consumption of fewer than 3 alcoholic drinks/wk is not associated with an increased risk of breast cancer, an intake of 3 to 6 drinks/wk might already yield a (small) increase in risk. On the other hand, intakes up to 1 drink/day are not associated to the risk of laryngeal, colorectal, and pancreatic cancer. The positive association between alcohol consumption and the risk of head and neck cancers is independent from tobacco exposure.

Role of DNA methyltransferase 1 in pharyngeal cancer related to treatment resistance

The purpose of the present study was to highlight the role of DNA methyltransferase 1 (DNMT1) and its potential for improving treatment and informing prognosis for pharyngeal cancer. Human pharyngeal cancer cell lines FaDu and its derivative FaDu-C225-R were selected for cellular experiments. Furthermore, 95 pharyngeal cancer tissue specimens were analyzed by immunohistochemical staining. DNMT1 was over-expressed in pharyngeal cancer specimens and cells with activated interleukin (IL)-6 signaling. When DNMT1 activity was blocked, accelerated tumor growth and treatment resistance were overcome as demonstrated by cell culture and animal experiments. The reduction in DNMT1 was associated with increased apoptosis, cell cycle arrest, and augmented irradiation-induced free radical levels and DNA damage. Furthermore, positive staining for DNMT1 in clinical cancer specimens was significantly linked to lower rates of response to treatments and shorter survival of patients with pharyngeal cancer. DNMT1 may be a significant clinical predictor and a potential treatment strategy against head and neck cancer.