No abstract

Previous studies demonstrated that certain glycosphingolipids (GSLs) are involved in various cell functions, such as cell growth and motility. Recent studies showed changes in GSL expression during differentiation of human embryonic stem cells; however, little is known about expression profiles of GSLs in cancer stem cells (CSCs). CSCs are a small subpopulation in cancer and are proposed as cancer-initiating cells, have been shown to be resistant to numerous chemotherapies, and may cause cancer recurrence. Here, we analyzed GSLs expressed in human breast CSCs by applying a CSC model induced through epithelial-mesenchymal transition, using mass spectrometry, TLC immunostaining, and cell staining. We found that (i) Fuc-(n)Lc4Cer and Gb3Cer were drastically reduced in CSCs, whereas GD2, GD3, GM2, and GD1a were greatly increased in CSCs; (ii) among various glycosyltransferases tested, mRNA levels for ST3GAL5, B4GALNT1, ST8SIA1, and ST3GAL2 were increased in CSCs, which could explain the increased expression of GD3, GD2, GM2, and GD1a in CSCs; (iii) the majority of GD2+ cells and GD3+ cells were detected in the CD44 hi /CD24 lo cell population; and (iv) knockdown of ST8SIA1 and B4GALNT1 significantly reduced the expression of GD2 and GD3 and caused a phenotype change from CSC to a non-CSC, which was detected by reduced mammosphere formation and cell motility. Our results provide insight into GSL profiles in human breast CSCs, indicate a functional role of GD2 and GD3 in CSCs, and suggest a possible novel approach in targeting human breast CSCs to interfere with cancer recurrence.

The process termed "epithelial-mesenchymal transition" (EMT) was originally discovered in ontogenic development, and has been shown to be one of the key steps in tumor cell progression and metastasis. Recently, we showed that the expression of some glycosphingolipids (GSLs) is down-regulated during EMT in human and mouse cell lines. Here, we demonstrate the involvement of GalNAc-type (or mucintype) O-glycosylation in EMT process, induced with transforming growth factor β (TGF-β) in human prostate epithelial cell lines. We found that: (i) TGF-β treatment caused up-regulation of oncofetal fibronectin (onfFN), which is defined by mAb FDC6, and expressed in cancer or fetal cells/tissues, but not in normal adult cells/tissues. The reactivity of mAb FDC6 requires the addition of an O-glycan at a specific threonine, inside the type III homology connective segment (IIICS) domain of FN. (ii) This change is associated with typical EMT characteristics; i.e., change from epithelial to fibroblastic morphology, enhanced cell motility, decreased expression of a typical epithelial cell marker, E-cadherin, and enhanced expression of mesenchymal markers. (iii) TGF-β treatment up-regulated mRNA level of FN containing the IIICS domain and GalNAc-T activity for the IIICS domain peptide substrate containing the FDC6 onfFN epitope. (iv) Knockdown of GalNAc-T6 and T3 inhibited TGF-β-induced up-regulation of onfFN and EMT process. (v) Involvement of GSLs was not detectable with the EMT process in these cell lines. These findings indicate the important functional role of expression of onfFN, defined by sitespecific O-glycosylation at IIICS domain, in the EMT process.O-glycosylated fibronectin | siRNA G lycoconjugates, such as glycosphingolipids (GSLs) and N-and O-linked glycoproteins, have been shown to play important roles in embryogenesis (1), tumorigenesis, and cancer progression (2). Specific types of glycosyl residues modulate particular signaling pathways and regulate cell phenotypes. For example, GM3 inhibits epithelial growth factor receptor (EGFR) activation (3, 4); GM2 associated with tetraspanine CD82 inhibits the activation of the hepatocyte growth factor receptor cMet (5); and O-Fucose glycans modulate Notch signaling, which controls the fate of many cell types (6-8).Epithelial-mesenchymal transition (EMT) was initially observed during early embryonic development and organ formation (9-11). Accumulating evidence has shown that the EMT process plays a key role in disease development, particularly in cancer progression to metastasis (10-14) and fibrosis (15). During EMT, cells lose their apical-basal polarity, change morphology to fibroblastic, display reduced expression of epithelial cell marker molecules such as E-cadherin (Ecad), and enhance expression of mesenchymal cell marker molecules such as fibronectin (FN), N-cadherin (Ncad), vimentin, and matrix-metalloproteinases (MMPs). When combined, these effects result in increased cell motility (10-15).Our recent studies found a reduction in specific GSLs (Gg4 and/ or GM2) in ...

Imaging metabolic dysfunction, a hallmark of solid tumors, usually requires radioactive tracers. Chemical exchange saturation transfer (CEST) imaging can potentially detect and visualize glucose uptake and metabolism, without the need for radioisotopes. Here, we tested the feasibility of using glucose CEST (glucoCEST) to image unlabeled glucose uptake in head and neck cancer by using a clinical 3T magnetic resonance imaging (MRI) scanner. The average CEST contrast between tumors and normal tissue in 17 patients was 7.58% (P = 0.006) in the 3–4 ppm offset frequency range and 5.06% (P = 0.02) in 1–5 ppm range. In a subgroup of eight patients, glucoCEST signal enhancement was higher in tumors than in normal muscle (4.98% vs. 1.28%, P < 0.021). We conclude that glucoCEST images of head and neck cancer can be obtained with a clinical 3T MRI scanner.

and Elekta AB outside the submitted work; and personal fees (travel funds and speaking honoraria) from Elekta AB outside the submitted work. The remaining authors reported no disclosures or conflicts of interest. Data Sharing Statement: The data is currently pending archival in a public repository (as of the time of publication). The data may be made available sooner to individual researchers upon request to the corresponding author.

Hypoxia is reported to be a biomarker for poor prognosis in cervical cancer. However, a practical non-invasive method is needed for routine clinical evaluation of tumor hypoxia. This study examined the potential use of BOLD (Blood Oxygenation Level Dependent) contrast MRI as a non-invasive technique to assess tumor vascular oxygenation at 3 T. Following IRB-approved informed consent and in compliance with HIPAA, successful results were achieved in nine patients with locally advanced cervical cancer (FIGO stage IIA to IVA) and three normal volunteers. In the first four patients, dynamic T2*-weighted MRI was performed in the transaxial plane using a multi-shot EPI sequence while patients breathed room air followed by oxygen (15 dm3/min). Later, a multi-echo gradient echo examination was added to provide quantitative R2* measurements. Baseline T2*-weighted signal intensity was quite stable, but increased to various extents in tumors upon initiation of oxygen breathing. Signal in normal uterus increased significantly, while iliacus muscle did not change. R2* responded significantly in healthy uterus, cervix, and eight cervical tumors. This preliminary study demonstrates that BOLD MRI of cervical cancer at 3 T is feasible. However, more patients must be evaluated and followed clinically before any prognostic value can be determined.

This study aims to identify the temporal kinetics of intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) in patients with human papillomavirus-associated (HPV+) oropharyngeal squamous cell carcinoma. Patients were enrolled under an IRB-approved protocol as part of ongoing prospective clinical trial. All patients underwent two MRI studies, a baseline scan before chemoradiotherapy and a midtreatment scan 3–4 weeks of treatment initiation. Parametric maps representing pure diffusion coefficient (D), pseudo-diffusion coefficient (D*), perfusion fraction (f), and apparent diffusion coefficient (ADC) were generated. The Mann-Whitney U test was used to assess temporal variation of IVIM metrics. Bayesian quadratic discriminant analysis (QDA) was used to evaluate the extent to which midtreatment changes in IVIM metrics could be combined to predict sites that would achieve complete response (CR) in multivariate analysis. A total of 31 patients were included in the final analysis with 59 lesions. Pretreatment ADC and D values of the complete response (CR) lesions (n=19) were significantly lower than non-CR lesions (n=33). Midtreatment ADC, D, and f values were significantly higher (P < .0001) than pretreatment values for all lesions. Each increase in normalized ΔADC of size 0.1 yielded a 1.45-fold increase in the odds of CR (P<.0003), each increase in normalized ΔD of size 0.1 yielded a 1.53-fold increase in the odds of CR (P<.0002), and each unit increase in Δf yielded a 2.29-fold increase in the odds of CR (P < .02). Combined ΔD and ΔADC were integrated into a multivariate prediction model and attained an AUC=0.87 (95% CI: 0.79, 0.96) as well as sensitivity=0.63, specificity=0.85, and accuracy=0.78 under leave-one-out cross-validation. In conclusion, IVIM is feasible and potentially useful in prediction and assessment of early response of HPV+ oropharyngeal squamous cell carcinoma to chemoradiotherapy.

Radiomics involves high-throughput extraction of large numbers of quantitative features from medical images and analysis of these features to predict patients’ outcome and support clinical decision-making. However, radiomics features are sensitive to several factors, including scanning protocols. The purpose of this study was to investigate the robustness of magnetic resonance imaging (MRI) radiomics features with various MRI scanning protocol parameters and scanners using an MRI radiomics phantom. The variability of the radiomics features with different scanning parameters and repeatability measured using a test–retest scheme were evaluated using the coefficient of variation and intraclass correlation coefficient (ICC) for both T1- and T2-weighted images. For variability measures, the features were categorized into three groups: large, intermediate, and small variation. For repeatability measures, the average T1- and T2-weighted image ICCs for the phantom (0.963 and 0.959, respectively) were higher than those for a healthy volunteer (0.856 and 0.849, respectively). Our results demonstrated that various radiomics features are dependent on different scanning parameters and scanners. The radiomics features with a low coefficient of variation and high ICC for both the phantom and volunteer can be considered good candidates for MRI radiomics studies. The results of this study will assist current and future MRI radiomics studies.