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P53 is an important biomarker in response to genotoxic stress, but it is also known to plays a key role in the regulation of metabolic homeostasis. The loss of p53 is a well-established contributor to the malignant transformation and glycolytic phenotype acquisition of cells during cancer development. However, the role of p53 in genotoxic therapy-induced metabolic shift in cancers remains unclear. Here, we attempted to elucidate how p53 participates in the glycolytic shift of head and neck cancer cell lines following irradiation. We established a stable radioresistant head and neck cancer cells (HN30-R; p53 wild type and UMSCC1-R; p53 null type) through cumulative irradiation and then analyzed their glucose metabolic profiles and mitochondria respiration. As a result, the metabolic analysis revealed no changes glycolysis of HN30-R cells, but UMSCC1-R cells exhibited increased glycolysis through increased glucose uptake and lactate production and glycolytic intermediates as well as related glycolytic enzymes, compared to UMSCC1 cells. Also, we confirmed that the mitochondrial respiration was reduced by the maximal respiration parameters of oxygen consumption rate (OCR) and that abnormal mitochondria were accumulated by electron microscopy in UMSCC1-R cells. Thus, UMSCC1-R cells exhibited an increased sensitivity to glycolysis-targeting drugs such a hexokinases inhibitor (2-deoxy-D-glucoes; 2-DG) and a lactate dehydrogenase-A inhibitor (AT101), but HN30-R cells did not shown any changes. Moreover, we identified that mitophagy limits glycolytic shift through the p53-dependent clearance of abnormal mitochondria. Taken together, these results suggest that p53 null type cells increased aerobic glycolysis to overcome the accumulation of abnormal mitochondria in radioresistnat cells. Conversely, p53 wild type cells inhibited the glycolytic shift by regulating a integrity through p53-dependent mitophagy. Thus, glycolysis-targeted drugs could be an alternative strategy for overcoming recurrent cancers after radiotherapy, and p53 status could be a biomarker for selecting participants for clinical trials. Citation Format: Hyo Won Chang, Ji Won Kim, Mi Ra Kim, Hae Yun Nam, Myungjin Lee, Won Hyeok Lee, Song Hee Kim, Da Seul Seong, Myung Woul Han, Jong Cheol Lee, Jung Je Park, Ji-hyun Seo, Seong Who Kim, Sang Yoon Kim. P53-dependent mitophagy controls glycolytic shift in radioresistant head and neck cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2405.

Tristetraprolin (TTP) is an AU-rich element-binding protein that regulates mRNA stability. Here, we report that TTP suppress the growth of human colon cancer cells both in vivo and in vitro by regulating of the expression of vascular endothelial growth factor (VEGF). TTP protein expression in human colonic tissues was markedly decreased in colonic adenocarcinoma compared with in normal mucosa and adenoma. VEGF expression was higher in colonic adenocarcinoma than in normal mucosa and adenoma. Specific inhibition of TTP expression by RNA-interference increased the expression of VEGF in cultured human colon cancer cells, and TTP overexpression markedly decreased it. In addition, elevated expression of TTP decreased the expression level of luciferase linked to a 3' terminal AU-rich element (ARE) of VEGF mRNA. Colo320/TTP cells overexpressing TTP grew slowly in vitro and became tumors small in size when xenografted s.c into nude mice. These findings demonstrate that TTP acts as a negative regulator of VEGF gene expression in colon cancer cells, suggesting that it can be used as novel therapeutic agent to treat colon cancer.

The presence of p53 mutation was associated with poor survival in various tumors. The involvement of p53 in apoptosis and cell-cycle control makes it a plausible biomarker of prognosis . Classifying TP53 mutations in HNSCC described disruptive TP53 mutation in either the L2 or L3 loop of the DNA binding domain, resulting in polarity change within the protein, or stop cordon. Disruptive TP53 mutation in HNSCC tumors predicts for locoregional recurrence, due to increased radioresistance via the inhibition of senescence. Senescence induction contributes to cancer therapy responses and is crucial for p53-mediated tumor suppression. However, whether p53 inactivation actively suppresses senescence induction has been unclear. Here, we found that overexpression CIP2A (cancerous inhibitor of protein phosphatase 2A) positively correlated with presence of p53 mutation in head and neck cancer and mediates radioresistance through suppression of radiation induced senescence. And we demonstrated that rapamycin could induce senescence via CIP2A downregulation and increase radiosensitivity in p53 disruptive mutation cell line. This is the first investigation to analyze the role of CI2A in resistance to the radiotherapy of head and neck cancer. As a consequence, a greater understanding of radioresistance mechanisms through our results in head and neck cancer with p53 mutation will enable the rational design of combination regimens and sequential treatment algorithms to improve clinical outcomes and points to the usefulness of CIP2A as a biomarker to predict clinical response to rapamycin in head and neck cancer. Citation Format: Song Hee Kim, Won hyeok Lee, Myung Jin Lee, Hyo Won Chang, Ji Won Kim, Mi Ra Kim, Jung Je Park, Myung Woul Han, Sang Yoon Kim. CIP2A can be a therapeutic target of rapamycin in radioresistant head and neck cancer with P53 mutation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5476. doi:10.1158/1538-7445.AM2017-5476

There are limited therapeutic options for patients with recurrent head and neck cancer after radiation therapy failure. To assess the use of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) as a salvage chemotherapeutic agent for recurrent cancer after radiation failure, we investigated the effect of clinically relevant cumulative irradiation on TRAIL-induced apoptosis.Using a previously established HN3 cell line from a laryngeal carcinoma patient, we generated a chronically irradiated HN3R isogenic cell line. Viability and apoptosis in HN3 and HN3R cells treated with TRAIL were analyzed with MTS and PI/annexin V-FITC assays. Western blotting and flow cytometry were used to determine the underlying mechanism of TRAIL resistance. DR4 expression was semiquantitatively scored in a tissue microarray with 107 laryngeal cancer specimens. Methylation-specific polymerase chain reaction and bisulfite sequencing for DR4 were performed for genomic DNA isolated from each cell line.HN3R cells were more resistant than HN3 cells to TRAIL-induced apoptosis because of significantly reduced levels of the DR4 receptor. The DR4 staining score in 37 salvage surgical specimens after radiation failure was lower in 70 surgical specimens without radiation treatment (3.03 ± 2.75 vs 5.46 ± 3.30, respectively; P.001). HN3R cells had a methylated DR4 CpG island that was partially demethylated by the DNA demethylating agent 5-aza-2'-deoxycytidine.Epigenetic silencing of the TRAIL receptor by hypermethylation of a DR4 CpG island might be an underlying mechanism for TRAIL resistance in recurrent laryngeal carcinoma treated with radiation.

e20544Background: CD70 is a co-stimulatory factor present on B-cells, activated T-cells, and dendritic cells. CD70 overexpression may induce cytotoxic effects in B-cells and T-cells, induce lymphoc...

Epidemiologic evidence supports a role for vitamin D in colorectal cancer (CRC) risk. Variants in vitamin D–related genes might modify the association between vitamin D levels and CRC risk. In this analysis, we did a comprehensive evaluation of common variants in the vitamin D receptor (VDR) and the vitamin D–binding protein (GC; group-specific component) genes using a population-based case–unaffected sibling control design that included 1,750 sibships recruited into the Colon Cancer Family Registry. We also evaluated whether any associations differed by calcium supplement use, family history of CRC, or tumor characteristics. Heterogeneity by calcium and vitamin D intake was evaluated for a subset of 585 cases and 837 sibling controls who completed a detailed food frequency questionnaire. Age- and sex-adjusted associations were estimated using conditional logistic regression. Overall, we did not find evidence for an association between any single-nucleotide polymorphism (SNP) in VDR or GC and risk for CRC (range of unadjusted P values 0.01-0.98 for VDR and 0.07-0.95 for GC). None of these associations was significant after adjustment for multiple comparisons. We also found no evidence that calcium or vitamin D intake (food and supplement) from the food frequency questionnaire modified the association estimates between VDR and GC SNPs and CRC. We did observe associations between SNPs in GC and microsatellite unstable CRC, although these results should be confirmed in additional studies. Overall, our results do not provide evidence for a role of common genetic variants in VDR or GC in susceptibility to CRC. Cancer Epidemiol Biomarkers Prev; 19(2); 525–36

Folate status is an important predictor of colorectal cancer risk. Common genetic variants in genes involved in regulating cellular folate levels might also predict risk, but there are limited data on this issue. We conducted a family-based case–control association study of variants in four genes involved in folate uptake and distribution: FOLR1, FPGS, GGH and SLC19A1, using 1,750 population-based and 245 clinic-based cases of pathologically confirmed colorectal cancer and their unaffected relatives participating in the Colon Cancer Family Registries. Standardized questionnaires, administered to all participants, collected information on risk factors and diet. Standard molecular techniques were used to determine microsatellite instability (MSI) status on cases. tagSNPs (n = 29) were selected based on coverage as assessed by pairwise r 2. We found no evidence that tagSNPs in these genes were associated with risk of colorectal cancer. For the SLC19A1-rs1051266 (G80A, Arg27His) missense polymorphism, the A/A genotype was not associated with risk of colorectal cancer using population-based (OR = 1.00; 95% CI = 0.81–1.23) or clinic-based (OR = 0.75; 95% CI = 0.44–1.29) families compared to the G/A and G/G genotypes. We found no evidence that the association between any tagSNP and CRC risk was modified by multivitamin use, folic acid use and dietary folate intake and total folate intake. The odds ratios were similar, irrespective of MSI status, tumor subsite and family history of colorectal cancer. In conclusion, we found no significant evidence that genetic variants in FOLR1, GGH, FPGS and SLC19A1 are associated with the risk of colorectal cancer.

The radiotherapy has been known as one of standard treatment methods in larynx cancer, and the many targeted therapies have been developed for improving radiotherapy. In this regard, the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can be one promising candidate, because TRAIL has a high selectivity for tumor cells and radiation efficiently sensitizes tumor cells towards apoptosis induction by TRAIL. It has been showing that irradiation strongly sensitizes malignant cells to TRAIL-induced apoptosis without any synergistic effects in normal tissues. Up to now, however, most studies have focused on immediate TRAIL-effect after small amount of irradiation. In this study, we aim to investigate the effect of chronic irradiation on TRAIL response to see if TRAIL could be an effective targeted therapy in recurrent laryngeal squamous cell carcinoma. Using previously established AMC-HN3 cell line from laryngeal SCCa patient, we have generated isogenic model of chronic irradiated HN3R cell line after every 2 or 3 day irradiation of 2 Gy/day of X-rays (70 Gy cumulative doses). Interestingly, through MTS assay, HN3R cells show much more resistance to TRAIL induced apoptosis than HN3 cells. Among suggested mechanisms, we found that a significantly reduced DR4 receptor is the cause of this resistance. Reverse transcription-PCR, western blotting and FACS analysis for DR4 receptors show that the expression of mRNA and the total amount, and surface expression of DR4 protein was much less in HN3R cells. Inhibition of DR4 by antagonistic antibody or si-DR4 significantly decreased TRAIL sensitivity in HN3 cells, and overexpression of DR4 enhanced the TRAIL sensitivity in HN3R cells. To evaluate this result in laryngeal cancer specimens, tissue microarray with 81 advanced laryngeal cancer specimens was constructed. Immunohistochemical assessment score of DR4 staining in 23 salvage surgical specimens after radiation failure shows statistically significant lower score than 58 surgical specimens without radiation treatment (3.09±2.23 vs. 4.43±3.36, p=0.040). Postulating that DR4 gene might be silenced by hypermethylation after long-term irradiation, methylation-specific PCR for DR4 was undertaken. Compared to HN3 cells, HN3R cells had a methylated 5’ regulatory CpG island that was partially demethylated by the DNA demethylating agent 5-aza-2’-deoxycytidine (5-AZAdC). In conclusion, chronic irradiation induces the TRAIL resistance by hypermethylation of CpG island of DR4 receptor in recurrent laryngeal squamous cell carcinoma. Thus, the status of receptor methylation might be one of biomarker to predict TRAIL response especially after radiation failure. Citation Format: Jong Cheol Lee, Won Hyeok Lee, Young Joo Min, Yoon-Se Lee, Jung Je Park, Seong Who Kim, Sang Yoon Kim. TRAIL resistance by radiation induced hypermethylation of DR4 CpG island in recurrent laryngeal squamous cell carcinoma . [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4431. doi:10.1158/1538-7445.AM2013-4431

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC Background: It is well established that the female sex steroids estrogen and progesterone are important in breast cancer etiology. It therefore seems plausible that variation in genes involved in biosynthesis and metabolism of these hormones may affect breast cancer risk. However, the results from genetic epidemiological studies investigating the role of variation in such genes so far have been mixed. We selected 27 genes in the estrogen and progesterone synthesis and metabolism pathway and investigated whether variation in these genes was associated with breast cancer risk. Methods: We analyzed data from a breast cancer case-control study nested in the California Teachers Study. We genotyped 365 tagging single nucleotide polymorphisms (SNPs) in 27 hormone pathway genes in 2746 non-Hispanic white women: 1351 cases and 1395 controls. Unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CI), adjusting for age and geographic area. We calculated P values adjusted for multiple correlated tests (PACT) within a gene. Results: The most significant associations were observed for several SNPs in SLCO1B1, a solute carrier organic anion transporter gene. SLCO1B1 is important in estrogen metabolism as it transports estradiol-17β-glucuronide and estrone-3-sulfate from the blood into the hepatocytes. Among the 38 tagging SNPs of SLCO1B1, 9 SNPs were associated with breast cancer risk with the smallest p-value (P=0.005) for rs11045773. Several SNPs in HSD17B4 ([rs382719][1] and rs17388769) and HSD17B3 ([rs394243][2]), both involved in hormone metabolism, also showed associations with breast cancer risk, but these were not statistically significant after correcting for multiple testing. When we examined the associations separately by menopausal status, 10 SNPs in SLCO1B1 showed significant associations with postmenopausal breast cancer risk, and 5 of them (rs11045777, rs11045773, rs16923519, rs4149057, rs11045884) remained statistically significant after adjusting for multiple testing within this gene. The smallest P value among postmenopausal women was obtained for rs11045777, with OR=0.77 (95% CI=0.65-0.90, P=0.0009, PACT=0.019). Among premenopausal women, rs17388769 in HSD17B4 was associated with breast cancer risk (OR=1.56, 95% CI=1.15-2.13, P=0.004, PACT=0.051). Polymorphisms in other hormone pathway genes tested in this study were not associated with breast cancer risk in pre- or postmenopausal women. Furthermore, after additional Bonferroni adjustment for the number of genes tested, none of the genetic associations presented here were statistically significant. Conclusions: We found some evidence that genetic variation in SLCO1B1 is associated with breast cancer risk. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2856. [1]: /lookup/external-ref?link_type=GEN&access_num=rs382719&atom=%2Fcanres%2F70%2F8_Supplement%2F2856.atom [2]: /lookup/external-ref?link_type=GEN&access_num=rs394243&atom=%2Fcanres%2F70%2F8_Supplement%2F2856.atom

The mechanism of action of arsenic trioxide (ATO) has been shown to be complex, influencing numerous signal transduction pathways and resulting in a vast range of cellular effects. Among these mechanisms of action, ATO has been shown to cause acute vascular shutdown and massive tumor necrosis in a murine solid tumor model like vascular disrupting agent (VDA). However, relatively little is understood about this VDA-like property and its potential utility in developing clinical regimens. We focused on this VDA-like action of ATO. On the basis of the endothelial cell cytotoxicity assay and tubulin polymerization assay, we observed that higher concentrations and longer treatment with ATO reduced the level of α- and β-tubulin and inhibited the polymerization of tubulin. The antitumor action and quantitative tumor perfusion studies were carried out with locally advanced murine CT26 colon carcinoma grown in female BALB/c mice. A single injection of ATO intraperitoneally displayed central necrosis of the tumor tissue by 24 hours. T1-weighted dynamic contrast-enhanced magnetic resonance image revealed a significant decrease in tumor enhancement in the ATO-treated group. Similar to other VDAs, ATO treatment alone did not delay the progression of tumor growth; however, ATO treatment after injection of other cytotoxic agent (irinotecan) showed significant additive antitumor effect compared to control and irinotecan alone therapy. In summary, our data demonstrated that ATO acts as a VDA by means of microtubule depolymerization. It exhibits significant vascular shutdown activity in CT26 allograft model and enhances antitumor activity when used in combination with another cytotoxic chemotherapeutic agent.