MicroRNA-92 Expression in CD133+ Melanoma Stem Cells Regulates Immunosuppression in the Tumor Microenvironment via Integrin-Dependent Activation of TGFβ

In addition to being refractory to treatment, melanoma cancer stem cells (CSC) are known to suppress host antitumor immunity, the underlying mechanisms of which need further elucidation. In this study, we established a novel role for miR-92 and its associated gene networks in immunosuppression. CSCs were isolated from the B16-F10 murine melanoma cell line based on expression of the putative CSC marker CD133 (Prominin-1). CD133⁺ cells were functionally distinct from CD133^- cells and showed increased proliferation in vitro and enhanced tumorigenesis in vivo. CD133⁺ CSCs also exhibited a greater capacity to recruit immunosuppressive cell types during tumor formation, including FoxP3⁺ Tregs, myeloid-derived suppressor cells (MDSC), and M2 macrophages. Using microarray technology, we identified several miRs that were significantly downregulated in CD133⁺ cells compared with CD133^- cells, including miR-92. Decreased expression of miR-92 in CSCs led to higher expression of target molecules integrin α_V and α₅ subunits, which, in turn, enhanced TGFβ activation, as evidenced by increased phosphorylation of SMAD2. CD133⁺ cells transfected with miR-92a mimic and injected in vivo showed significantly decreased tumor burden, which was associated with reduced immunosuppressive phenotype intratumorally. Using The Cancer Genome Atlas database of patients with melanoma, we also noted a positive correlation between integrin α₅ and TGFβ1 expression levels and an inverse association between miR-92 expression and integrin alpha subunit expression. Collectively, this study suggests that a miR-92-driven signaling axis involving integrin activation of TGFβ in CSCs promotes enhanced tumorigenesis through induction of intratumoral immunosuppression. SIGNIFICANCE: CD133⁺ cells play an active role in suppressing melanoma antitumor immunity by modulating miR-92, which increases influx of immunosuppressive cells and TGFβ1 expression.

Prospective study of plasma levels of coenzyme Q10 and lung cancer risk in a low-income population in the Southeastern United States

Background

Coenzyme Q10 (CoQ10) is a ubiquitous molecule in living organisms serving as a cofactor in energy production. Epidemiological studies have reported low CoQ10 levels being associated with an increased risk of various cancers. We conducted the first study to evaluate the association of CoQ10 concentrations with lung cancer risk.

Methods

A nested case‐control study including 201 lung cancer cases and 395 matched controls from the Southern Community Cohort Study was conducted. Plasma CoQ10 levels were measured using high‐performance liquid chromatography with photo‐diode array detection. Conditional logistic regression models were applied to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between plasma CoQ10 levels and lung cancer risk.

Results

Plasma CoQ10 concentration was inversely associated with the risk of lung cancer. After adjusting for age, sex, race, and socioeconomic status, the OR (95% CI) comparing the third to first tertile was 0.57 (0.36–0.91, P for trend = 0.02). Further adjustments for smoking, alcohol, chronic obstructive pulmonary disease, and body mass index attenuated the point estimate slightly (OR = 0.60, 95% CI = 0.34–1.08, P for trend = 0.11), comparing third to first tertiles. Stratified analyses identified a significant inverse association between plasma CoQ10 levels and lung cancer risk in current smokers, but not in former/never smokers. The association was more evident in cases who were diagnosed within 1 year of blood draw than in cases diagnosed after 1 year.

Conclusions

Low plasma CoQ10 was significantly associated with increased lung cancer risk, particularly among current smokers. The stronger association seen shortly following the blood draw suggests that CoQ10 may be related to disease progression.

Validation of syngeneic mouse models of melanoma and non-small cell lung cancer for investigating the anticancer effects of the soy-derived peptide Lunasin

Background: Lunasin is a naturally occurring peptide present in soybean that has both chemopreventive and therapeutic activities that can prevent cellular transformation and inhibit the growth of several human cancer types. Recent studies indicate that Lunasin has several distinct potential modes of action including suppressing integrin signaling and epigenetic effects driven by modulation of histone acetylation. In addition to direct effects on cancer cells, Lunasin also has effects on innate immunity that may contribute to its ability to inhibit tumor growth in vivo.

Methods: Standard assays for cell proliferation and colony formation were used to assess Lunasin’s in vitro activity against murine Lewis lung carcinoma (LLC) and B16-F0 melanoma cells.  Lunasin’s in vivo activity was assessed by comparing the growth of tumors initiated by subcutaneous implantation of LLC or B16-F0 cells in Lunasin-treated and untreated C57BL/6 mice.

Results: Lunasin was found to inhibit growth of murine LLC cells and murine B16-F0 melanoma cells in vitro and in wild-type C57BL/6 mice.  The effects of Lunasin in these two mouse models were very similar to those previously observed in studies of human non-small cell lung cancer and melanoma cell lines.

Conclusions: We have now validated two established syngeneic mouse models as being responsive to Lunasin treatment.  The validation of these two in vivo syngeneic models will allow detailed studies on the combined therapeutic and immune effects of Lunasin in a fully immunocompetent mouse model.

Validation of syngeneic mouse models of melanoma and non-small cell lung cancer for investigating the anticancer effects of the soy-derived peptide Lunasin

Background : Lunasin is a naturally occurring peptide present in soybean that has both chemopreventive and therapeutic activities that can prevent cellular transformation and inhibit the growth of several human cancer types. Recent studies indicate that Lunasin has several distinct potential modes of action including suppressing integrin signaling and epigenetic effects driven by modulation of histone acetylation. In addition to direct effects on cancer cells, Lunasin also has effects on innate immunity that may contribute to its ability to inhibit tumor growth in vivo. Methods: Standard assays for cell proliferation and colony formation were used to assess Lunasin's in vitro activity against murine Lewis lung carcinoma (LLC) and B16-F0 melanoma cells.  Lunasin's in vivo activity was assessed by comparing the growth of tumors initiated by subcutaneous implantation of LLC or B16-F0 cells in Lunasin-treated and untreated C57BL/6 mice. Results: Lunasin was found to inhibit growth of murine LLC cells and murine B16-F0 melanoma cells in vitro and in wild-type C57BL/6 mice.  The effects of Lunasin in these two mouse models were very similar to those previously observed in studies of human non-small cell lung cancer and melanoma cell lines. Conclusions: We have now validated two established syngeneic mouse models as being responsive to Lunasin treatment.  The validation of these two in vivo syngeneic models will allow detailed studies on the combined therapeutic and immune effects of Lunasin in a fully immunocompetent mouse model.

Associations of Pre-Diagnostic Serum Levels of Total Bilirubin and Albumin With Lung Cancer Risk: Results From the Southern Community Cohort Study

Background

Previous studies conducted among European and Asian decedents reported inverse associations of serum total bilirubin and albumin with lung cancer risk. Yet, no study has been conducted among African Americans or low-income European Americans.

Methods

This study included 522 incident lung cancer cases and 979 matched controls nested in the Southern Community Cohort Study, a cohort of predominantly low-income African and European Americans. Serum levels of total bilirubin and albumin, collected up to 11 years prior to case diagnoses, were measured by a clinical chemistry analyzer. Conditional logistic regression models were applied to evaluate the associations of total bilirubin and albumin with lung cancer risk.

Results

Overall, serum levels of total bilirubin (ORT3 vs. T1 = 0.96, 95% CI: 0.66-1.39) were not significantly associated with lung cancer risk. However, higher levels of serum total bilirubin were significantly associated with decreased risk of lung cancer among participants who were diagnosed within two years following sample collection (ORT3 vs. T1 = 0.36, 95% CI: 0.15-0.87) and among former/never smokers (ORT3 vs. T1 = 0.54, 95% CI: 0.32-0.93). Serum levels of albumin were significantly associated with decreased risk of lung cancer overall (ORT3 vs. T1 = 0.70, 95% CI: 0.50-0.98) and among African Americans (ORT3 vs. T1 = 0.62, 95% CI: 0.41-0.96), but not among European Americans.

Conclusion

Our results indicate that in a low-income African American and European American population, serum levels of total bilirubin may be related to lung cancer progression and differ by smoking status. Meanwhile, the association of serum albumin levels with lung cancer risk may differ by race. Further studies are warranted to confirm these results.

Functional Genomic Analyses of the 21q22.3 Locus Identifying Functional Variants and Candidate Gene YBEY for Breast Cancer Risk

Simple Summary

Previous research has revealed a genetic predisposition to breast carcinogenesis. Thus, identifying causal genetic variants and their associated gene networks may improve breast cancer diagnostics and risk assessment. Our study investigated YBEY, an uncharacterized gene in humans, and its functions in breast cancer risk and progression. We identified two genetic variants associated with YBEY expression that may have causal functions in breast cancer risk. We performed in vitro functional assays using MCF-7, T47D, and MDA-MB-231 breast cancer cell lines and showed that knockdown of YBEY expression significantly inhibited proliferation, colony formation, and invasion/migration. We utilized RNA sequencing to identify gene networks associated with YBEY knockdown including inflammation and metabolic pathways. Further, we used data available in The Cancer Genome Atlas to explore trends in YBEY expression patterns in normal and tumor tissues. Our study provides a role for YBEY in breast carcinogenesis, and further studies investigating its mechanistic functions are warranted.

Abstract

We previously identified a locus at 21q22.3, tagged by the single nucleotide polymorphism (SNP) rs35418111, being associated with breast cancer risk at a genome-wide significance level; however, the underlying causal functional variants and gene(s) responsible for this association are unknown. We performed functional genomic analyses to identify potential functional variants and target genes that may mediate this association. Functional annotation for SNPs in high linkage disequilibrium (LD, r² > 0.8) with rs35418111 in Asians showed evidence of promoter and/or enhancer activities, including rs35418111, rs2078203, rs8134832, rs57385578, and rs8126917. These five variants were assessed for interactions with nuclear proteins by electrophoretic mobility shift assays. Our results showed that the risk alleles for rs2078203 and rs35418111 altered DNA-protein interaction patterns. Cis-expression quantitative loci (cis-eQTL) analysis, using data from the Genotype-Tissue Expression database (GTEx) European-ancestry female normal breast tissue, indicated that the risk allele of rs35418111 was associated with a decreased expression of the YBEY gene, a relatively uncharacterized endoribonuclease in humans. We investigated the biological effects of YBEY on breast cancer cell lines by transient knock-down of YBEY expression in MCF-7, T47D, and MDA-MB-231 cell lines. Knockdown of YBEY mRNA in breast cancer cell lines consistently decreased cell proliferation, colony formation, and migration/invasion, regardless of estrogen receptor status. We performed RNA sequencing in MDA-MB-231 cells transfected with siRNA targeting YBEY and subsequent gene set enrichment analysis to identify gene networks associated with YBEY knockdown. These data indicated YBEY was involved in networks associated with inflammation and metabolism. Finally, we showed trends in YBEY expression patterns in breast tissues from The Cancer Genome Atlas (TCGA); early-stage breast cancers had elevated YBEY expression compared with normal tissue, but significantly decreased expression in late-stage disease. Our study provides evidence of a significant role for the human YBEY gene in breast cancer pathogenesis and the association between the rs35418111/21q22.3 locus and breast cancer risk, which may be mediated through functional SNPs, rs35418111 and rs2078203, that regulate expression of YBEY.

Abstract 595: Circulating levels of coenzyme Q10 and lung cancer risk

Background: Coenzyme Q10 (CoQ10) is an ubiquitous molecule in living organisms that serves as a cofactor in energy production via the electron-transport chain (ETC). Research has previously shown that deficiencies in CoQ10 can result in a variety of detrimental outcomes including cardiovascular disease and neurological disorders. More recently, epidemiological studies have reported low CoQ10 levels being associated with increased risk of breast, ovarian, and skin cancers. However, studies exploring the link between CoQ10 and lung cancer risk are largely lacking.

Methods: A nested case-control study including 201 lung cancer cases and 395 matched controls from the Southern Community Cohort Study (SCCS) was conducted. Plasma CoQ10 levels were measured using high-performance liquid chromatography (HPLC). A conditional logistic regression model was applied to estimate the odds ratio (OR) and 95% confidence interval (CI) for the association between plasma CoQ10 concentrations and lung cancer risk. CoQ10 level was categorized by tertile distribution among controls.

Results: Plasma CoQ10 concentration was inversely associated with risk of lung cancer. Compared to the first tertile, the ORs (95% CI) were 0.82 (0.52-1.31) and 0.57 (0.34-0.96) for the second and third tertile, respectively, (P for trend=0.038), after adjusting for age, smoking status and pack-years of smoking. Additional adjustment for alcohol consumption, education, income, history of COPD and BMI slightly attenuated the association (OR=0.60, 95% CI=0.34-1.08, comparing third to first tertile). No notable difference was found between African Americans and European Americans. Stratified analysis identified a significant association between CoQ10 and lung cancer in current smokers (OR=0.47, 95% CI=0.26-0.87, third vs. first tertile), but not in former/never smokers (OR=0.84, 95% CI=0.35-2.03). The significant associations between CoQ10 and lung cancer risk were more evident in cases who were diagnosed within one year of blood draw (OR=0.17, 95% CI=0.04-0.73, third vs. first tertile, P for trend=0.023) than in cases diagnosed after one year following blood draw (OR=0.72, 95% CI=0.36-1.41).

Conclusions: Findings from this study suggest that Coenzyme Q10 may be a potential marker for lung cancer, although the stronger effect shortly after diagnosis indicates the association may be related to dietary or other changes associated with the cancer diagnosis rather than CoQ10 being a causal risk biomarker. Further studies exploring the link between CoQ10 and lung cancer risk are necessary to better understand the role of CoQ10 in lung carcinogenesis.

Citation Format: Chris Shidal, Hyung-Suk Yoon, Wei Zheng, Jie Wu, Adrian A. Franke, William J. Blot, Xiao-Ou Shu, Qiuyin Cai. Circulating levels of coenzyme Q10 and lung cancer risk [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 595.

MicroRNA-92 expression in CD133+ melanoma stem cells regulates immunosuppression in the tumor microenvironment through integrin-dependent TGF-β activation

The existence of cancer stem cells (CSC) accounts for the high degree of chemoresistance and heterogeneity characterizing refractory melanomas. Yet, the degree to which CSCs modulate immune cells in the tumor microenvironment has yet to be revealed. The present study aims to establish a novel role for miR-92 and its associated gene networks in immunomodulation. We employed syngeneic mouse models utilizing B16-F10 melanoma cells to observe primary tumor and metastatic growth. CSCs were isolated from the parental line based on expression of the putative CSC marker, CD133. CD133+ cells were functionally distinct from CD133− cells with CD133+ cells showing increased proliferation in vitro and enhanced tumorigenesis when administered subcutaneously. Our data indicated that compared to CD133− cells, CD133+ CSCs had a greater capacity to recruit immunosuppressive cell types during tumor formation. Using microarray technology in order to expose disparities in microRNA expression between CSC and non-CSC compartments, we identified several miRs that were significantly downregulated in CD133+ cells including miR-92. We hypothesized that lower levels of miR-92 in CSCs led to higher expression of integrin subunits as predicted by gene alignment software and confirmed using qRT-PCR. Flow cytometry analysis of dissociated tumors demonstrated that tumors initiated by CD133+ cells displayed significantly higher levels of TGF-β compared to CD133− cells. Additionally, qRT-PCR for TGF-β associated genes confirmed a significant increase in expression in CD133+ cells. These data suggest that CSCs efficiently induce intratumoral immunosuppression which is potentially regulated by a miR-92 driven axis involving integrin activation of TGF-β.

Pre-diagnostic circulating p53 autoantibodies and subsequent lung cancer risk in low-income African and European Americans

INTRODUCTION

Mutations of the TP53 gene lead to the production of autoantibodies against p53, a major tumor suppressor protein. Although studies have indicated the association of p53 autoantibodies with human cancers, epidemiologic evidence on lung cancer is still lacking.

METHODS

In this nested case-control study conducted within the Southern Community Cohort Study, we investigated the association of circulating p53 autoantibodies with the subsequent risk of developing lung cancer. Using blood samples collected prior to any cancer diagnosis from 295 cases and their individually matched controls, seroreactivity to p53 was assessed by fluorescent bead-based multiplex serology. Conditional logistic regression models were used to estimate odds ratios (OR) and 95 % confidence intervals (CI) for lung cancer risk associated with p53 autoantibodies.

RESULTS

After adjustment for potential confounders, p53 seropositivity was significantly associated with an increased risk of lung cancer (OR=2.98, 95 % CI: 1.10-8.06) among African Americans, but not among European Americans (OR=1.21, 95 % CI: 0.24-6.15). The positive associations were restricted to men (OR=4.59, 95 % CI: 1.30-16.16) and participants with a short interval (≤ 4 years) from blood collection to diagnosis (OR=4.30, 95 % CI: 1.33-13.89).

CONCLUSION

Our findings add to the evidence supporting p53 autoantibodies as a biomarker of lung cancer.

Abstract 4616: Functional genomic analyses of 21q22.3 locus identify potential functional variants and candidate gene YBEY for breast cancer risk

We have previously identified SNP rs3541811, located in the 21q22.3 locus, to be associated with breast cancer risk in Asians. However, the underlying causal functional variants and gene(s) responsible for this association are unknown. In this study, we performed functional genomic analyses to identify potential functional variants and target genes that may mediate this association. Functional annotation for SNPs highly correlated with rs3541881, using epigenetic data from the Encyclopedia of DNA Elements (ENCODE) and Roadmap projects, showed evidence of promoter and/or enhancer activities of five putative functional SNPs, including rs35418111, rs2078203, rs8134832, rs57385578, and rs8126917. These SNPs were assessed for interactions with nuclear proteins by EMSA assay. Our results showed that compared to the reference allele, alternate allele rs2078203 (A > G) significantly increased DNA-protein interactions, while an opposite trend was observed for rs35418111 (G > A). Cis-expression quantitative loci (eQTL) analysis, using data from the Genotype-Tissue Expression (GTEx) project, The Cancer Genome Atlas (TCGA), Molecular Taxonomy of Breast Cancer International Consortium (METABRIC), and the Shanghai Breast Cancer Study, indicated that the risk allele rs35418111 is associated with a decreased expression of the YBEY (C21or57) gene, indicating its putative oncogenic function that may contribute to breast cancer risk. The gene YBEY is a relatively uncharacterized endoribonuclease in humans, which is thought to function in rRNA cleavage and maturation, similar to its bacterial homologues. We further investigated whether YBEY may have any biological effect in human breast cancers by knocking-down YBEY gene expression using siRNA in MCF-7, T47D, and MDA-MB-231 cell lines. Transient knockdown of YBEY gene expression in three breast cancer cell lines consistently affected cell proliferation, colony formation, and migration/invasion, regardless of hormone receptor status. Our study provides support for a significant role for human YBEY gene in breast cancer pathogenesis and the association between the rs35418111/21q22.3 locus and breast cancer risk, which may be mediated through its correlated potential functional SNPs that regulate expression of the YBEY gene.

Citation Format: Chris Shidal, Xiang Shu, Jie Wu, Jifeng Wang, Shuya Huang, Joshua Bauer, Xingyi Guo, Wei Zheng, Xiao-Ou Shu, Qiuyin Cai. Functional genomic analyses of 21q22.3 locus identify potential functional variants and candidate gene YBEY for breast cancer risk [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4616.

TBX1 functions as a putative oncogene of breast cancer through promoting cell cycle progression

We have previously identified a genetic variant, rs34331122 in the 22q11.21 locus, as being associated with breast cancer risk in a genome-wide association study. This novel variant is located in the intronic region of the T-box transcription factor 1 (TBX1) gene. Cis-expression quantitative trait loci analysis showed that expression of TBX1 was regulated by the rs34331122 variant. In the current study, we investigated biological functions and potential molecular mechanisms of TBX1 in breast cancer. We found that TBX1 expression was significantly higher in breast cancer tumor tissues than adjacent normal breast tissues and increased with tumor stage (P < 0.05). We further knocked-down TBX1 gene expression in three breast cancer cell lines, MDA-MB-231, MCF-7 and T47D, using small interfering RNAs and examined consequential changes on cell oncogenicity and gene expression. TBX1 knock-down significantly inhibited breast cancer cell proliferation, colony formation, migration and invasion. RNA sequencing and flow cytometry analysis revealed that TBX1 knock-down in breast cancer cells induced cell cycle arrest in the G1 phase through disrupting expression of genes involved in the cell cycle pathway. Furthermore, survival analysis using the online Kaplan-Meier Plotter suggested that higher TBX1 expression was associated with worse outcomes in breast cancer patients, especially for estrogen receptor-positive breast cancer, with HRs (95% CIs) for overall survival (OS) and distant metastasis free survival (DMFS) of 1.5 (1.05-2.15) and 1.55 (1.10-2.18), respectively. In conclusion, our results suggest that the TBX1 gene may act as a putative oncogene of breast cancer through regulating expressions of cell cycle-related genes.

Associations between Plasma Tocopherols and Lung Cancer Risk: Results from the Southern Community Cohort Study

BACKGROUND

Despite the various anticancer activities of tocopherols, little is known about tocopherols associated with lung cancer risk among low-income African Americans (AA) and European Americans (EA) who are disproportionately affected by the disease.

METHODS

We conducted a nested case-control study that included 209 incident lung cancer cases and 406 matched controls within the Southern Community Cohort Study. Using biospecimens collected at cohort enrollment, plasma levels of α-, β/γ-, δ-, and total-tocopherols were measured by high-performance liquid chromatography with photodiode array detection. Conditional logistic regression was used to estimate ORs and 95% confidence intervals (CI) for lung cancer risk after adjusting for potential confounders. Stratified analyses were also conducted.

RESULTS

Plasma levels of total-tocopherols were inversely associated with lung cancer risk overall [OR (95% CI) for the highest vs. lowest tertile = 0.51 (0.30-0.90)]. The inverse association remained significant among EAs [0.20 (0.06-0.65)], men [0.43 (0.21-0.90)], current smokers [0.49 (0.26-0.93)], and cases diagnosed within 2 years of blood draw [0.36 (0.15-0.86)], though we did not find a significant risk reduction among AAs [0.75 (0.39-1.45)]. Notably, we found significant interactions between α-tocopherol and race after controlling the FDR to correct for multiple comparisons (Pinteraction = 0.02).

CONCLUSIONS

Our results indicate that plasma total-tocopherols are inversely associated with lung cancer risk, but the association may differ across specific isomeric forms of tocopherols, race, or other individuals' characteristics. Further large-scale studies are warranted to confirm our findings.

IMPACT

Recommendations on tocopherols for lung cancer prevention should take isomers, race, and smoking behaviors into consideration.

Associations of lung cancer risk with biomarkers of Helicobacter pylori infection

Helicobacter pylori infection has been suggested to be associated with lung cancer risk. However, information is lacking on whether the association differs by H. pylori antigen. We conducted a nested case-control study within the Southern Community Cohort Study, including 295 incident lung cancer cases and 295 controls. Helicobacter pylori multiplex serology assay was performed to detect antibodies to 15 H. pylori proteins. Conditional logistic regression was used to estimate odds ratios (ORs) and confidence intervals (95% CIs) after adjustment for covariates. Overall H. pylori+ was associated with a non-statistically significant increased risk of lung cancer (OR: 1.29; 95% CI: 0.85-1.95). Significant associations, however, were observed for H. pylori+ VacA+ (OR: 1.64; 95% CI: 1.02-2.62) and H. pylori+ Catalase+ (OR: 1.75; 95% CI: 1.11-2.77). The positive association of H. pylori+ Catalase+ with lung cancer risk was predominantly seen among African Americans (OR: 2.09; 95% CI: 1.11-3.95) but not European Americans (OR: 1.20; 95% CI: 0.56-2.54). Among participants who smoked ≥ 30 pack-years, overall H. pylori+ (OR: 1.85; 95% CI: 1.02-3.35), H. pylori+ CagA+ (OR: 2.77; 95% CI: 1.35-5.70), H. pylori+ VacA+ (OR: 2.53; 95% CI: 1.25-5.13) and H. pylori+ HP1564+ (OR: 2.01; 95% CI: 1.07-3.77) were associated with increased risk of lung cancer. Our study provides novel evidence that associations of H. pylori infection with lung cancer risk differ by H. pylori biomarker, may be more evident among African Americans and may be modified by smoking habits. Furthermore, studies are warranted to confirm our findings.