Amsacrine downregulates BCL2L1 expression and triggers apoptosis in human chronic myeloid leukemia cells through the SIDT2/NOX4/ERK/HuR pathway.

Accumulating evidence indicates that the anticancer activity of acridine derivatives is mediated through the regulation of anti-apoptotic and pro-apoptotic BCL2 protein expression. Therefore, we investigated whether the cytotoxicity of amsacrine with an acridine structural scaffold in human chronic myeloid leukemia (CML) K562 cells was mediated by BCL2 family proteins. Amsacrine induced apoptosis, mitochondrial depolarization, and BCL2L1 (also known as BCL-XL) downregulation in K562 cells. BCL2L1 overexpression inhibited amsacrine-induced cell death and mitochondrial depolarization. Amsacrine treatment triggered SIDT2-mediated miR-25 downregulation, leading to increased NOX4-mediated ROS production. ROS-mediated inactivation of ERK triggered miR-22 expression, leading to increased HuR mRNA decay. As HuR is involved in stabilizing BCL2L1 mRNA, downregulation of BCL2L1 was noted in K562 cells after amsacrine treatment. In contrast, amsacrine-induced BCL2L1 downregulation was alleviated by restoring ERK phosphorylation and HuR expression. Altogether, the results of this study suggest that amsacrine triggers apoptosis in K562 cells by inhibiting BCL2L1 expression through the SIDT2/NOX4/ERK-mediated downregulation of HuR. Furthermore, a similar pathway also explains the cytotoxicity of amsacrine in CML MEG-01 and KU812 cells.

Effects of SIDT2 on the miR-25/NOX4/HuR axis and SIRT3 mRNA stability lead to ROS-mediated TNF-α expression in hydroquinone-treated leukemia cells.

Our previous studies indicated that the benzene metabolite hydroquinone (HQ) evokes the ROS/p38 MAPK/protein phosphatase 2A/tristetraprolin axis, leading to increased TNF-α expression in human acute myeloid leukemia cell lines U937 and HL-60. In this study, we aimed to identify the upstream pathway involved in ROS-mediated TNF-α expression. HQ treatment increased SIDT2 expression, which subsequently decreased miR-25 and SIRT3 expression in U937 cells. Notably, miR-25 downregulation promoted SIDT2 expression in HQ-treated U937 cells. SIDT2 induced lysosomal degradation of SIRT3 mRNA, but inhibited miR-25 expression through a lysosome-independent pathway. MiR-25 inhibition reduced NOX4 mRNA turnover, resulting in increased NOX4 protein levels. NOX4 induces mitochondrial ROS production and HuR downregulation. Restoration of HuR expression increased SIRT3 expression, suggesting that NOX4-mediated HuR downregulation promotes SIDT2-mediated degradation of SIRT3 mRNA. Inhibition of NOX4 or SIRT3 overexpression abolished HQ-induced ROS production, thereby abolishing TNF-α upregulation. Overall, these results indicate that SIDT2 regulates the miR-25/NOX4/HuR axis and SIRT3 mRNA destabilization, leading to ROS-mediated TNF-α upregulation in HQ-treated U937 cells. HQ-induced increase in TNF-α expression in HL-60 cells was also mediated through a similar pathway.

CREB/Sp1-mediated MCL1 expression and NFκB-mediated ABCB1 expression modulate the cytotoxicity of daunorubicin in chronic myeloid leukemia cells.

Although some studies have hinted at the therapeutic potential of daunorubicin (DNR) in chronic myeloid leukemia (CML), the mechanism by which DNR induces CML cell death is unclear. Therefore, this study aimed to investigate DNR-induced cell death signaling pathways in CML cell lines K562 and KU812. DNR-triggered apoptosis in K562 cells was characterized by inhibition of MCL1 expression, while restoration of MCL1 expression protected K562 cells from DNR-mediated cytotoxicity. In addition, DNR induced NOX4-dependent ROS production, leading to the activation of p38 MAPK and inactivation of Akt and ERK. Activated p38 MAPK stimulated protein phosphatase 2A-dependent dephosphorylation of CREB. Since Akt-mediated activation of ERK reduced ß-TrCP mRNA stability, the inactivation of Akt-ERK axis increased ß-TrCP expression, which in turn promoted proteasomal degradation of Sp1. Inhibition of CREB phosphorylation and Sp1 expression simultaneously reduced MCL1 transcription and protein expression. DNR-induced MCL1 suppression was not reliant on its ability to induce DNA damage. In addition, DNR induced the expression of drug exporter ABCB1 in K562 cells through the p38 MAPK/NFκB-mediated pathway, while imatinib or ABT-199 inhibited the DNR-induced effect. The combination of imatinib or ABT-199 with DNR showed synergistic cytotoxicity in K562 cells by increasing intracellular DNR retention. Cumulatively, our data indicate that DNR induces MCL1 downregulation in K562 cells by promoting p38 MAPK-mediated dephosphorylation of CREB and inhibiting the Akt-ERK axis-mediated Sp1 protein stabilization. Furthermore, experimental evidence indicates that DNR-induced death of KU812 cells occurs through a similar pathway.

Functional and structural properties of cardiotoxin isomers produced by blocking negatively charged groups.

In this study, we investigated the functional roles of Asp40, Asp57, and C-terminal Asn60 in Naja atra cardiotoxin 3 (CTX3) structure and function by modifying these three carboxyl groups with semicarbazide. The conjugation of the carboxyl groups with semicarbazide produced two conformational isomers whose gross and fine structures were different from those of CTX3. The blocking of the carboxyl groups increased the structural flexibility of CTX3 in response to trifluoroethanol-induced effect. Despite presenting modest to no effect on decreasing the induction of permeability in zwitterionic phospholipid vesicles, the carboxyl group-modified CTX3 showed a marked reduction in its permeabilizing effect on anionic phospholipid vesicles in comparison to that of the native protein. Compared with native CTX3, carboxyl group-modified CTX3 exhibited lower activity in inducing membrane leakage in U937 cells. The CD spectra of lipid-bound toxins and the color transition of polydiacetylene/lipid assay showed that the membrane interaction mode of CTX3 was distinctly changed by the modification in the carboxyl groups. Given that the selective modification of Asp40 does not cause the conformational isomerization of CTX3, our data indicate that the carboxyl groups in Asp57 and Asn60 are essential in maintaining the structural topology of CTX3. Furthermore, modification of carboxyl groups changes the interdependence between the infrastructure and the global conformation of CTX3 in modulating membrane permeabilizing activity.

Carboxyl group-modified myoglobin shows membrane-permeabilizing activity.

In this study, we investigated whether modification of the carboxyl group with semicarbazide-enabled myoglobin (Mb) exhibits membrane-perturbing activity in physiological solutions. Mass spectrometry analysis showed that semicarbazide molecules were coupled to 19 of the 22 carboxyl groups in semicarbazide-modified Mb (SEM-Mb). Measurements of the absorption and circular dichroism spectra indicated that SEM-Mb lost its heme group and reduced the content of the α-helix structure in Mb. The microenvironment surrounding Trp residues in Mb changes after blocking negatively charged residues, as shown by fluorescence quenching studies. The results of the trifluoroethanol-induced structural transition indicated that SEM-Mb had higher structural flexibility than that of Mb. SEM-Mb, but not Mb, induced the permeability of bilayer membranes. Both proteins showed similar lipid-binding affinities. The conformation of SEM-Mb and Mb changed upon binding to lipid vesicles or a membrane-mimicking environment composed of SDS micelles, suggesting that membrane interaction modes differ. Unlike lipid-bound Mb, Trp residues in lipid-bound SEM-Mb are located at the protein-lipid interface. Altogether, our data indicate that modifying negatively charged groups relieves the structural constraints in Mb, consequently switching Mb structure to an active conformation that exhibits membrane-permeabilizing activity.

NOXA-mediated degradation of MCL1 and BCL2L1 causes apoptosis of daunorubicin-treated human acute myeloid leukemia cells.

Daunorubicin (DNR) is used clinically to treat acute myeloid leukemia (AML), while the signaling pathways associated with its cytotoxicity are not fully elucidated. Thus, we investigated the DNR-induced death pathway in the human AML cell lines U937 and HL-60. DNR-induced apoptosis in U937 cells accompanied by downregulation of MCL1 and BCL2L1, upregulation of Phorbol-12-myristate-13-acetate-induced protein 1 (NOXA), and mitochondrial depolarization. DNR induced NOX4-mediated reactive reactive oxygen species (ROS) production, which in turn inactivated Akt and simultaneously activated p38 mitogen-activated protein kinase (MAPK). Activated p38 MAPK and inactivated Akt coordinately increased GSK3ß-mediated cAMP response element-binding protein (CREB) phosphorylation, which promoted NOXA transcription. NOXA upregulation critically increased the proteasomal degradation of MCL1 and BCL2L1. The same pathway was also responsible for the DNR-induced death of HL-60 cells. Restoration of MCL1 or BCL2L1 expression alleviated DNR-induced mitochondrial depolarization and cell death. Furthermore, ABT-199 (a BCL2 inhibitor) synergistically enhanced the cytotoxicity of DNR in AML cell lines. Notably, DNR-induced DNA damage was not related to NOXA-mediated degradation of MCL1 and BCL2L1. Collectively, these results indicate that the upregulation of NOXA expression through the NOX4-ROS-p38 MAPK-GSK3ß-CREB axis results in the degradation of MCL1 and BCL2L1 in DNR-treated U937 and HL-60 cells. This signaling pathway may provide insights into the mechanism underlying DNR-triggered apoptosis in AML cells.

GSK3ß suppression inhibits MCL1 protein synthesis in human acute myeloid leukemia cells.

Previous studies have shown that glycogen synthase kinase 3ß (GSK3ß) suppression is a potential strategy for human acute myeloid leukemia (AML) therapy. However, the cytotoxic mechanism associated with GSK3ß suppression remains unresolved. Thus, the underlying mechanism of N-(4-methoxybenzyl)-N'-(5-nitro-1,3-thiazol-2-yl)urea (AR-A014418)-elicited GSK3ß suppression in the induction of AML U937 and HL-60 cell death was investigated in this study. Our study revealed that AR-A014418-induced MCL1 downregulation remarkably elicited apoptosis of U937 cells. Furthermore, the AR-A014418 treatment increased p38 MAPK phosphorylation and decreased the phosphorylated Akt and ERK levels. Activation of p38 MAPK subsequently evoked autophagic degradation of 4EBP1, while Akt inactivation suppressed mTOR-mediated 4EBP1 phosphorylation. Furthermore, AR-A014418-elicited ERK inactivation inhibited Mnk1-mediated eIF4E phosphorylation, which inhibited MCL1 mRNA translation in U937 cells. In contrast to GSK3α, GSK3ß downregulation recapitulated the effect of AR-A014418 in U937 cells. Transfection of constitutively active GSK3ß or cotransfection of constitutively activated MEK1 and Akt suppressed AR-A014418-induced MCL1 downregulation. Moreover, AR-A014418 sensitized U937 cells to ABT-263 (BCL2/BCL2L1 inhibitor) cytotoxicity owing to MCL1 suppression. Collectively, these results indicate that AR-A014418-induced GSK3ß suppression inhibits ERK-Mnk1-eIF4E axis-modulated de novo MCL1 protein synthesis and thereby results in U937 cell apoptosis. Our findings also indicate a similar pathway underlying AR-A014418-induced death in human AML HL-60 cells.

Lessons learned from the INHANCE consortium: An overview of recent results on head and neck cancer.

OBJECTIVE: To summarize the latest evidence on head and neck cancer epidemiology from the International Head and Neck Cancer Epidemiology (INHANCE) consortium. SUBJECTS AND METHODS: INHANCE was established in 2004 to elucidate the etiology of head and neck cancer through pooled analyses of individual-level data on a large scale. We summarize results from recent INHANCE-based publications updating our 2015 overview. RESULTS: Seventeen papers were published between 2015 and May 2020. These studies further define the nature of risks associated with tobacco and alcohol, and occupational exposures on head and neck cancer. The beneficial effects on incidence of head and neck cancer were identified for good oral health, endogenous and exogenous hormonal factors, and selected aspects of diet related to fruit and vegetables. INHANCE has begun to develop risk prediction models and to pool follow-up data on their studies, finding that ~30% of cases had cancer recurrence and 9% second primary cancers, with overall- and disease-specific 5-year-survival of 51% and 57%, respectively. CONCLUSIONS: The number and importance of INHANCE scientific findings provides further evidence of the advantages of large-scale internationally collaborative projects and will support the development of prevention strategies.

SIRT3, PP2A and TTP protein stability in the presence of TNF-α on vincristine-induced apoptosis of leukaemia cells.

The contribution of vincristine (VCR)-induced microtubule destabilization to evoke apoptosis in cancer cells remains to be resolved. Thus, we investigated the cytotoxic mechanism of VCR on U937 and HL-60 human leukaemia cell lines. We discovered that VCR treatment resulted in the up-regulation of TNF-α expression and activation of the death receptor pathway, which evoked apoptosis of U937 cells. Moreover, VCR induced microtubule destabilization and mitotic arrest. VCR treatment down-regulated SIRT3, and such down-regulation caused mitochondrial ROS to initiate phosphorylation of p38 MAPK. p38 MAPK suppressed MID1-modulated degradation of the protein phosphatase 2A (PP2A) catalytic subunit. The SIRT3-ROS-p38 MAPK-PP2A axis inhibited tristetraprolin (TTP)-controlled TNF-α mRNA degradation, consequently, up-regulating TNF-α expression. Restoration of SIRT3 and TTP expression, or inhibition of the ROS-p38 MAPK axis increased the survival of VCR-treated cells and repressed TNF-α up-regulation. In contrast to suppression of the ROS-p38 MAPK axis, overexpression of SIRT3 modestly inhibited the effect of VCR on microtubule destabilization and mitotic arrest in U937 cells. Apoptosis of HL-60 cells, similarly, went through the same pathway. Collectively, our data indicate that the SIRT3-ROS-p38 MAPK-PP2A-TTP axis modulates TNF-α expression, which triggers apoptosis of VCR-treated U937 and HL-60 cells. We also demonstrate that the apoptotic signalling is not affected by VCR-elicited microtubule destabilization.

Tobacco smoking, chewing habits, alcohol drinking and the risk of head and neck cancer in Nepal.

Although tobacco smoking, pan chewing and alcohol drinking are important risk factors for head and neck cancer (HNC), the HNC risks conferred by products available in Nepal for these habits are unknown. We assessed the associations of tobacco smoking, chewing habits, and alcohol drinking with HNC risk in Nepal. A case-control study was conducted in Nepal with 549 incident HNC cases and 601 controls. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using unconditional logistic regression adjusting for potential confounders. We observed increased HNC risk for tobacco smoking (OR: 1.54; 95% CI: 1.14, 2.06), chewing habits (OR: 2.39; 95% CI: 1.77, 3.23), and alcohol drinking (OR: 1.57; 95% CI: 1.14, 2.18). The population attributable fraction (PAF) was 24.3% for tobacco smoking, 39.9% for chewing habits and 23.0% for alcohol drinking. Tobacco smoking, chewing habits, and alcohol drinking might be responsible for 85.3% of HNC cases. Individuals who smoked tobacco, chewed products and drank alcohol had a 13-fold increase in HNC risk (OR: 12.83; 95% CI: 6.91, 23.81) compared to individuals who did not have any of these habits. Both high frequency and long duration of these habits were strong risk factors for HNC among the Nepalese with clear dose-response trends. Preventive strategies against starting these habits and support for quitting these habits are necessary to decrease the incidence of HNC in Nepal.

Risk Prediction Models for Head and Neck Cancer in the US Population From the INHANCE Consortium.

Head and neck cancer (HNC) risk prediction models based on risk factor profiles have not yet been developed. We took advantage of the large database of the International Head and Neck Cancer Epidemiology (INHANCE) Consortium, including 14 US studies from 1981-2010, to develop HNC risk prediction models. Seventy percent of the data were used to develop the risk prediction models; the remaining 30% were used to validate the models. We used competing-risk models to calculate absolute risks. The predictors included age, sex, education, race/ethnicity, alcohol drinking intensity, cigarette smoking duration and intensity, and/or family history of HNC. The 20-year absolute risk of HNC was 7.61% for a 60-year-old woman who smoked more than 20 cigarettes per day for over 20 years, consumed 3 or more alcoholic drinks per day, was a high school graduate, had a family history of HNC, and was non-Hispanic white. The 20-year risk for men with a similar profile was 6.85%. The absolute risks of oropharyngeal and hypopharyngeal cancers were generally lower than those of oral cavity and laryngeal cancers. Statistics for the area under the receiver operating characteristic curve (AUC) were 0.70 or higher, except for oropharyngeal cancer in men. This HNC risk prediction model may be useful in promoting healthier behaviors such as smoking cessation or in aiding persons with a family history of HNC to evaluate their risks.

Dietary glycaemic index, glycaemic load and head and neck cancer risk: a pooled analysis in an international consortium.

High dietary glycaemic index (GI) and glycaemic load (GL) may increase cancer risk. However, limited information was available on GI and/or GL and head and neck cancer (HNC) risk. We conducted a pooled analysis on 8 case-control studies (4081 HNC cases; 7407 controls) from the International Head and Neck Cancer Epidemiology (INHANCE) consortium. We estimated the odds ratios (ORs) and 95% confidence intervals (CIs) of HNC, and its subsites, from fixed- or mixed-effects logistic models including centre-specific quartiles of GI or GL. GI, but not GL, had a weak positive association with HNC (ORQ4 vs. Q1 = 1.16; 95% CI = 1.02-1.31). In subsites, we found a positive association between GI and laryngeal cancer (ORQ4 vs. Q1 = 1.60; 95% CI = 1.30-1.96) and an inverse association between GL and oropharyngeal cancer (ORQ4 vs. Q1 = 0.78; 95% CI = 0.63-0.97). This pooled analysis indicates a modest positive association between GI and HNC, mainly driven by laryngeal cancer.

Arsenic trioxide-induced p38 MAPK and Akt mediated MCL1 downregulation causes apoptosis of BCR-ABL1-positive leukemia cells.

In this study, we investigated the mechanisms underlying arsenic trioxide (ATO)-induced death of human BCR-ABL1-positive K562 and MEG-01 cells. ATO-induced apoptotic death in K562 cells was characterized by ROS-mediated mitochondrial depolarization, MCL1 downregulation, p38 MAPK activation, and Akt inactivation. ATO-induced BCR-ABL1 downregulation caused Akt inactivation but not p38 MAPK activation. Akt inactivation increased GSK3ß-mediated MCL1 degradation, while p38 MAPK-mediated NFκB activation coordinated with HDAC1 suppressed MCL1 transcription. Inhibition of p38 MAPK activation or overexpression of constitutively active Akt increased MCL1 expression and promoted the survival of ATO-treated cells. Overexpression of MCL1 alleviated mitochondrial depolarization and cell death induced by ATO. The same pathway was found to be involved in ATO-induced death in MEG-01 cells. Remarkably, YM155 synergistically enhanced the cytotoxicity of ATO on K562 and MEG-01 cells through suppression of MCL1 and survivin. Collectively, our data indicate that ATO-induced p38 MAPK- and Akt-mediated MCL1 downregulation triggers apoptosis in K562 and MEG-01 cells, and that p38 MAPK activation is independent of ATO-induced BCR-ABL1 suppression.

Autophagic HuR mRNA degradation induces survivin and MCL1 downregulation in YM155-treated human leukemia cells.

The aim of this study was to investigate the mechanism of YM155 cytotoxicity in human chronic myeloid leukemia (CML) cells. YM155-induced apoptosis of human CML K562 cells was characterized by ROS-mediated p38 MAPK activation, mitochondrial depolarization, and survivin and MCL1 downregulation. Moreover, YM155-induced autophagy caused degradation of HuR mRNA and downregulation of HuR protein expression, which resulted in destabilized survivin and MCL1 mRNA. Interestingly, survivin and MCL1 suppression contributed to autophagy-mediated HuR mRNA destabilization in YM155-treated cells. Pretreatment with inhibitors of p38 MAPK or autophagy alleviated YM155-induced autophagy and apoptosis in K562 cells, as well as YM155-induced downregulation of HuR, survivin, and MCL1. Ectopic overexpression of HuR, survivin, or MCL1 attenuated the cytotoxic effect of YM155 on K562 cells. Conversely, YM155 sensitized K562 cells to ABT-199 (a BCL2 inhibitor), and circumvented K562 cell resistance to ABT-199 because of its inhibitory effect on survivin and MCL1 expression. Overall, our data indicate that YM155-induced apoptosis is mediated by inducing autophagic HuR mRNA degradation, and reveal the pathway responsible for YM155-induced downregulation of survivin and MCL1 in K562 cells. Our findings also indicate a similar pathway underlying YM155-induced death in human CML MEG-01 cells.

Compound C induces autophagy and apoptosis in parental and hydroquinone-selected malignant leukemia cells through the ROS/p38 MAPK/AMPK/TET2/FOXP3 axis.

Hydroquinone (HQ), a major metabolic product of benzene, causes acute myeloid leukemia (AML) elicited by benzene exposure. Past studies found that continuous exposure of human AML U937 cells to HQ selectively produces malignant U937/HQ cells in which FOXP3 upregulation modulates malignant progression. Other studies revealed that AMPK promotes TET2 activity on DNA demethylation and that TET2 activity is crucial for upregulating FOXP3 expression. This study was conducted to elucidate whether compound C, an AMPK inhibitor, blocked the AMPK-TET2-FOXP3 axis in AML and in HQ-selected malignant cells. We found higher levels of AMPKα, TET2, and FOXP3 expression in U937/HQ cells compared to U937 cells. Treatment of parental Original Article and HQ-selected malignant U937 cells with compound C induced ROS-mediated p38 MAPK activation, leading to a suppression of AMPKα, TET2, and FOXP3 expression. Moreover, compound C induced apoptosis and mTOR-independent autophagy. The suppression of the autophagic flux inhibited the apoptosis of compound C-treated U937 and U937/HQ cells, whereas co-treatment with rapamycin, a mTOR inhibitor, sensitized the two cell lines to compound C cytotoxicity. Overexpression of AMPKα1 or pretreatment with autophagic inhibitors abrogated compound C-induced autophagy and suppression of TET2 and FOXP3 expression. Restoration of AMPKα1 or FOXP3 expression increased cell survival after treatment with compound C. In conclusion, our results show that compound C suppresses AMPK/TET2 axis-mediated FOXP3 expression and induces autophagy-dependent apoptosis in parental and HQ-selected malignant U937 cells, suggesting that the AMPK/TET2/FOXP3 axis is a promising target for improving AML therapy and attenuating benzene exposure-induced AML progression.

Albendazole-Induced SIRT3 Upregulation Protects Human Leukemia K562 Cells from the Cytotoxicity of MCL1 Suppression.

Previous studies have shown that MCL1 stabilization confers cancer cells resistance to microtubule targeting agents (MTAs) and functionally extends the lifespan of MTA-triggered mitotically arrested cells. Albendazole (ABZ), a benzimidazole anthelmintic, shows microtubule-destabilizing activity and has been repositioned for cancer therapies. To clarify the role of MCL1 in ABZ-induced apoptosis, we investigated the cytotoxicity of ABZ on human leukemia K562 cells. Treatment with ABZ for 24 h did not appreciably induce apoptosis or mitochondrial depolarization in K562 cells, though it caused the mitotic arrest of K562 cells. ABZ-evoked p38 MAPK activation concurrently suppressed Sp1-mediated MCL1 expression and increased SIRT3 mRNA stability and protein expression. ABZ and A-1210477 (an MCL1 inhibitor) enhanced the cytotoxicity of ABT-263 (a BCL2/BCL2L1 inhibitor) to their effect on MCL1 suppression. Unlike ABZ, A-1210477 did not affect SIRT3 expression and reduced the survival of K562 cells. Overexpression of SIRT3 attenuated the A-1210477 cytotoxicity on K562 cells. ABZ treatment elicited marked apoptosis and ΔΨm loss in ABT-263-resistant K562 (K562/R) cells, but did not alter SIRT3 expression. Ectopic expression of SIRT3 alleviated the cytotoxicity of ABZ on K562/R cells. Collectively, our data demonstrate that ABZ-induced SIRT3 upregulation delays the apoptosis-inducing effect of MCL1 suppression on apoptosis induction in K562 cells.

Fiber intake and the risk of head and neck cancer in the prostate, lung, colorectal and ovarian (PLCO) cohort.

Although the protective role of dietary fiber on cancer risk has been reported in several epidemiological studies, the association of fiber intake on head and neck cancer (HNC) risk is still unclear. We investigated the association between fiber intake and the risk of HNC using data from the Prostate, Lung, Colorectal and Ovarian (PLCO) cancer screening trial. Among 101,700 participants with complete dietary information, 186 participants developed HNC during follow-up (January 1998 to May 2011). Dietary data were collected using a self-administered food-frequency questionnaire (1998-2005). We estimated hazard ratios (HRs) and the corresponding 95% confidence intervals (CI), using the Cox proportional hazards model. Higher intake of total fiber, insoluble fiber and soluble fiber was associated with decreased HNC risks, with a significant trend. The HRs of highest vs. the lowest tertile of intake were 0.43 (95%CI: 0.25-0.76) for total fiber, 0.38 (95%CI: 0.22-0.65) for insoluble fiber, and 0.44 (95%CI: 0.25-0.79) for soluble fiber. These inverse association were consistent in oral cavity and pharyngeal cases, but the impact of fiber intake was weaker in laryngeal cases. We did not observe any significant interaction of potential confounders, including smoking and drinking, with total fiber intake on HNC risk. These findings support evidence of a protective role of dietary fiber on HNC risk.

Shared and Study-specific Dietary Patterns and Head and Neck Cancer Risk in an International Consortium.

BACKGROUND: A few papers have considered reproducibility of a posteriori dietary patterns across populations, as well as pattern associations with head and neck cancer risk when multiple populations are available. METHODS: We used individual-level pooled data from seven case-control studies (3844 cases; 6824 controls) participating in the International Head and Neck Cancer Epidemiology consortium. We simultaneously derived shared and study-specific a posteriori patterns with a novel approach called multi-study factor analysis applied to 23 nutrients. We derived odds ratios (ORs) and 95% confidence intervals (CIs) for cancers of the oral cavity and pharynx combined, and larynx, from logistic regression models. RESULTS: We identified three shared patterns that were reproducible across studies (75% variance explained): the Antioxidant vitamins and fiber (OR = 0.57, 95% CI = 0.41, 0.78, highest versus lowest score quintile) and the Fats (OR = 0.80, 95% CI = 0.67, 0.95) patterns were inversely associated with oral and pharyngeal cancer risk. The Animal products and cereals (OR = 1.5, 95% CI = 1.1, 2.1) and the Fats (OR = 1.8, 95% CI = 1.4, 2.3) patterns were positively associated with laryngeal cancer risk, whereas a linear inverse trend in laryngeal cancer risk was evident for the Antioxidant vitamins and fiber pattern. We also identified four additional study-specific patterns, one for each of the four US studies examined. We named them all as Dairy products and breakfast cereals, and two were associated with oral and pharyngeal cancer risk. CONCLUSION: Multi-study factor analysis provides insight into pattern reproducibility and supports previous evidence on cross-country reproducibility of dietary patterns and on their association with head and neck cancer risk. See video abstract at, http://links.lww.com/EDE/B430.

The impact of folate intake on the risk of head and neck cancer in the prostate, lung, colorectal, and ovarian cancer screening trial (PLCO) cohort.

BACKGROUND: Although low levels of folate leads to disturbances in DNA replication, DNA methylation and DNA repair, the association between dietary folate intake and head and neck cancer (HNC) risk remains unclear. METHODS: We evaluated the association between folate intake and HNC risk using prospective cohort data from the Prostate, Lung, Colorectal, and Ovarian (PLCO) cancer screening trial. This study included 101 700 participants and 186 cases with confirmed incident HNC. The median follow-up was 12.5 years. We estimated hazard ratios (HRs) and the corresponding 95% confidence intervals (CIs) using Cox proportional hazard model including age, sex, body mass index, education, race, tobacco smoking, alcohol drinking and total fruit and vegetable intake. RESULTS: Higher intake of food folate and fortified folic acid in foods was associated with a decreasing HNC risk in a dose-response manner. The HRs of highest vs the lowest quartile of intake were 0.35 (95%CI: 0.18-0.67) for food folate, and 0.49 (95%CI: 0.30-0.82) for fortified folic acid. Intakes of total folate, natural folate and supplemental folic acid were not associated with the risk of HNC and its subsites. We did not detect any interaction between smoking, drinking and food folate intake on HNC risk. CONCLUSIONS: These findings provide evidence of the protective role of dietary folate intake on HNC risk.

Racial differences in the relationship between tobacco, alcohol, and the risk of head and neck cancer: pooled analysis of US studies in the INHANCE Consortium.

There have been few published studies on differences between Blacks and Whites in the estimated effects of alcohol and tobacco use on the incidence of head and neck cancer (HNC) in the United States. Previous studies have been limited by small numbers of Blacks. Using pooled data from 13 US case-control studies of oral, pharyngeal, and laryngeal cancers in the International Head and Neck Cancer Epidemiology Consortium, this study comprised a large number of Black HNC cases (n = 975). Logistic regression was used to estimate adjusted odds ratios (OR) and 95% confidence intervals (CI) for several tobacco and alcohol consumption characteristics. Blacks were found to have consistently stronger associations than Whites for the majority of tobacco consumption variables. For example, compared to never smokers, Blacks who smoked cigarettes for > 30 years had an OR 4.53 (95% CI 3.22-6.39), which was larger than that observed in Whites (OR 3.01, 95% CI 2.73-3.33; pinteraction < 0.0001). The ORs for alcohol use were also larger among Blacks compared to Whites. Exclusion of oropharyngeal cases attenuated the racial differences in tobacco use associations but not alcohol use associations. These findings suggest modest racial differences exist in the association of HNC risk with tobacco and alcohol consumption.