Stage-Specific Embryonic Antigen-1 (SSEA-1) Expression in Thyroid Tissues

Heterogeneous Sox2 transcriptional dynamics mediate pluripotency maintenance in mESCs in response to LIF signaling perturbations

The LIF signaling pathway and its regulation of internal factors like Sox2 is crucial for maintaining self-renewal and pluripotency in mESCs. However, the direct impact of LIF signaling on Sox2 transcriptional dynamics at the single-cell level remains elusive. Here, we employ PP7/PCP-mediated live imaging to analyze the transcriptional dynamics of Sox2 under perturbation of the LIF signaling pathway at single-cell resolution. Removal of the LIF ligand or addition of a JAK inhibitor heterogeneously affects the cell population, reducing the number of Sox2-active cells, rather than completely abolishing Sox2 expression. Moreover, Sox2-active cells under LIF perturbation exhibit significant reductions in mRNA production per cell. This reduction is characterized by decreased size and frequency of transcriptional bursting, resulting in shorter duration of Sox2 activity. Notably, cells with reduced or absent Sox2 expression demonstrate a significant loss in pluripotency, indicating that a reduction in Sox2 transcription (rather than a complete loss) is sufficient to trigger the transition from embryonic to an early differentiated state. In LIF-perturbed cells with Sox2 expression reduced to about 50% of non-perturbed levels, we observe a binary behavior, with cells either retaining or losing pluripotency-associated traits. Lastly, we find Sox2 expression is transcriptionally inherited across cell cycles, with Sox2-active mother cells more likely to reactivate Sox2 after mitosis compared to Sox2-inactive cells. This robust transcriptional memory is observed independent of LIF signaling perturbation. Our findings provide new insights into the transcriptional regulation of Sox2, advancing our understanding of the quantitative thresholds of gene expression required for pluripotency maintenance and highlighting the power of single-cell approaches to unravel dynamic regulatory mechanisms.

SSEA-1 Correlates With the Invasive Phenotype in Breast Cancer

The glycan moiety Lewis X (LeX) has been implicated in defining progenitor cells as well as playing a role in the progression of solid tumors, including breast cancer. Here, we used the original stage-specific embryonic antigen-1 (SSEA-1) antibody, MC-480, targeting the LeX motif to examine the expression pattern of this marker within the context of a differentiation hierarchy as well as functional properties of breast cancer cells. Immunohistochemical staining revealed the presence of SSEA-1 in a progenitor zone in the normal breast gland. In breast cancer, 81 of 220 carcinomas (37%) were positive for SSEA-1 and a distinct pattern could be correlated to major subtypes. Specifically, estrogen receptor alpha (ERα)-negative tumors showed a higher frequency of SSEA-1 expression compared to ERα-positive tumors, which are generally considered more differentiated (56% vs 29%, p<0.005). Functional assays performed on two representative breast cancer cell lines demonstrated that SSEA-1-expressing cells exhibited cancer stem cell properties as well as having more invasive potential, regardless of ERα status. A potential role of SSEA-1 in metastasis was confirmed by pairwise staining of primary- and corresponding lymph node tumors. Altogether, our data suggest that expression of SSEA-1 in breast cancer contributes to the malignant phenotype.

Stemness potency and structural characteristics of thyroid cancer cell lines

BACKGROUND

Thyroid cancer is the most frequent type of endocrine malignancy. Thyroid carcinomas are derived from the follicular epithelium and classified as papillary (PTC) (85%), follicular (FTC) (12%), and anaplastic (ATC) (<3%). Thyroid cancer could arise from thyroid cancer stem-like cells (CSCs). CSCs are cancer cells that feature stem-like properties. Kruppel-like factor (KLF4) and Stage-spesific embryonic antigen 1 (SSEA-1) are types of stem cell markers. Filamentous actin (F-actin) is an essential part of the cellular cytoskeleton. The purpose of this study was to evaluate the stem cell potency and the spatial distribution of the cytoskeletal element F-actin in PTC, FTC, and ATC cell lines.

MATERIALS AND METHODS

Normal thyroid cell line (NTC) Nthy-ori-3-1, PTC cell line BCPAP, FTC cell line FTC-133 and ATC cell line 8505c were stained with SSEA-1 and KLF4 for stem cell potency and F-actin for cytoskeleton. The morphological properties of cells were assessed by a scanning electron microscope (SEM) and elemental ratios were compared with EDS.

RESULTS

PTCs had greater percentages of SSEA-1 and KLF4 protein intensity (0.32% and 0.49%, respectively) than NTCs. ATCs had a greater proportion of KLF4 expression (0.8%) than NTCs. NTCs and FTCs had increased F-actin intensity across the cell, but PTCs had the lowest among these four cell lines. NTCs and PTCs, as well as NTCs and FTCs, have statistically identical aspect ratios and round values. These values, however, were statistically different in ATCs.

CONCLUSION

The study of stem cell markers and the cytoskeletal element F-actin in cancer and normal thyroid cell lines may assist in the identification of new therapeutic targets and contribute in the understanding of treatment resistance mechanisms.

MicroRNAs and exosomes: Cardiac stem cells in heart diseases

Treating cardiovascular diseases with cardiac stem cells (CSCs) is a valid treatment among various stem cell-based therapies. With supplying the physiological need for cardiovascular cells as their main function, under pathological circumstances, CSCs can also reproduce the myocardial cells. Although studies have identified many of CSCs' functions, our knowledge of molecular pathways that regulate these functions is not complete enough. Either physiological or pathological studies have shown, stem cells proliferation and differentiation could be regulated by microRNAs (miRNAs). How miRNAs regulate CSC behavior is an interesting area of research that can help us study and control the function of these cells in vitro; an achievement that may be beneficial for patients with cardiovascular diseases. The secretome of stem and progenitor cells has been studied and it has been determined that exosomes are the main source of their secretion which are very small vesicles at the nanoscale and originate from endosomes, which are secreted into the extracellular space and act as key signaling organelles in intercellular communication. Mesenchymal stem cells, cardiac-derived progenitor cells, embryonic stem cells, induced pluripotent stem cells (iPSCs), and iPSC-derived cardiomyocytes release exosomes that have been shown to have cardioprotective, immunomodulatory, and reparative effects. Herein, we summarize the regulation roles of miRNAs and exosomes in cardiac stem cells.

Elucidating the mechanisms of Temozolomide resistance in gliomas and the strategies to overcome the resistance

Temozolomide (TMZ) is a first-choice alkylating agent inducted as a gold standard therapy for glioblastoma multiforme (GBM) and astrocytoma. A majority of patients do not respond to TMZ during the course of their treatment. Activation of DNA repair pathways is the principal mechanism for this phenomenon that detaches TMZ-induced O-6-methylguanine adducts and restores genomic integrity. Current understanding in the domain of oncology adds several other novel mechanisms of resistance such as the involvement of miRNAs, drug efflux transporters, gap junction's activity, the advent of glioma stem cells as well as upregulation of cell survival autophagy. This review describes a multifaceted account of different mechanisms responsible for the intrinsic and acquired TMZ-resistance. Here, we summarize different strategies that intensify the TMZ effect such as MGMT inhibition, development of novel imidazotetrazine analog, and combination therapy; with an aim to incorporate a successful treatment and increased overall survival in GBM patients.

Asymptomatic neurotoxicity of amyloid β-peptides (Aβ1-42 and Aβ25-35) on mouse embryonic stem cell-derived neural cells

One of the strategies in the establishment of in vitro oxidative stress models for neurodegenerative diseases, such as Alzheimer's disease (AD), is to induce neurotoxicity by amyloid beta (Aβ) peptides in suitable neural cells. Presently, data on the neurotoxicity of Aβ in neural cells differentiated from stem cells are limited. In this study, we attempted to induce oxidative stress in transgenic 46C mouse embryonic stem cell-derived neurons via treatment with Aβ peptides (Aβ1-42 and Aβ25-35). 46C neural cells were generated by promoting the formation of multicellular aggregates, embryoid bodies in the absence of leukemia inhibitory factor, followed by the addition of all-trans retinoic acid as the neural inducer. Mature neuronal cells were exposed to different concentrations of Aβ1-42 and Aβ25-35 for 24 h. Morphological changes, cell viability, and intracellular reactive oxygen species (ROS) production were assessed. We found that 100 µM Aβ1-42 and 50 µM Aβ25-35 only promoted 40% and 10%, respectively, of cell injury and death in the 46C-derived neuronal cells. Interestingly, treatment with each of the Aβ peptides resulted in a significant increase of intracellular ROS activity, as compared to untreated neurons. These findings indicate the potential of using neurons derived from stem cells and Aβ peptides in generating oxidative stress for the establishment of an in vitro AD model that could be useful for drug screening and natural product studies.

Prognostic Implications of CD10 and CD15 Expression in Papillary Thyroid Carcinoma

Patients with papillary thyroid carcinoma (PTC) have excellent survival, but recurrence remains a major problem in the management of PTC. We aimed to determine the prognostic impact of the expression of CD10 and CD15 in patients with PTC. Immunohistochemistry for CD10 and CD15 was performed on the tissue microarrays of 515 patients with PTC. The expression of CD10 and CD15 was detected in 201 (39.0%) and 295 (57.3%) of 515 PTC cases, respectively, but not in the adjacent benign thyroid tissue. Recurrence was inversely correlated with CD15 expression (p = 0.034) but not with CD10 expression. In 467 PTC patients treated with radioiodine remnant ablation, the CD15 expression had an adjusted hazard ratio of 0.500 (p = 0.024) for recurrence-free survival and an adjusted odds ratio of 2.678 (p = 0.015) for predicting long-term excellent therapeutic response. CD10 expression was not associated with clinical outcomes. In the Cancer Genome Atlas dataset, the expression level of FUT4 (CD15) mRNA was higher in the low/intermediate-risk group for recurrence than in the high-risk group and exhibited positive correlation with SLC5A5 (NIS) mRNA expression (p = 0.003). Taken together, CD15 expression was identified as an independent prognostic marker for improved prognosis in PTC patients.

Papillary Renal Neoplasm With Reverse Polarity: A Clinicopathologic Study of 7 Cases

Papillary renal neoplasm with reverse polarity is a form of recently described tumor. These tumors are defined by GATA3 positivity, negative vimentin staining, and the presence of both papillary structures and a layer of eosinophilic cells with apical nuclei and a granular cytoplasm. In the present report, we review 7 cases of papillary renal neoplasm with reverse polarity that were GATA3+ and vimentin-, consistent with past reports. In all 7 of these cases, we found that these tumors were additionally positive for 34βE12. All 7 of these tumors were categorized as stage pT1. On histological examination, these tumors exhibited branching papillae with apical nuclei. All 7 of these patients were alive on most recent follow-up, with 6 being disease free and one having developed prostate cancer. Together, this overview of 7 additional cases of papillary renal neoplasm with reverse polarity offers further insight into this rare and poorly understood disease.

Immunohistochemical Analysis of Cancer Stem Cell Marker Expression in Papillary Thyroid Cancer

Cancer stem cell (CSC) markers have prognostic significance in various cancers, but their clinical significance in papillary thyroid carcinoma (PTC) has not been demonstrated. In this study, CSC markers expressed in PTC and their relationships with prognosis were evaluated. We constructed tissue microarrays for 386 PTC cases, divided it into 42 low risk cases and 344 intermediate risk cases according to the American Thyroid Association 2009 Risk Stratification System. Immunohistochemical staining of CSC markers (CD15, CD24, CD44, CD166, and ALDH1A1) was performed, and the proportion of stained cells and immunostaining intensity were evaluated to determine positive marker expression. The relationships between CSC marker expression and other clinicopathological parameters or survival were analyzed. CD15 expression was higher in PTC with intermediate risk than in PTC with low risk (29.4 vs. 11.9%, p = 0.017). According to a multivariate analysis, CD15, CD44, CD166, and ALDH1A1 positivity were independently associated with a shorter progression-free survival (PFS) (odds ratio [OR]: 1.929, 2.960, 7.485, and 3.736; p = 0.016, p = 0.026, p < 0.001, and p = 0.006, respectively). Higher N and cancer stage were the only other clinical factors associated with a shorter PFS (OR: 2.953 and 1.898, p = 0.011 and p = 0.034). Overexpression of CSC markers in PTC was associated with shorter PFS during follow-up. Immunohistochemical staining of CSC markers may provide useful information for predicting patient outcomes.

The evolving concept of cancer stem-like cells in thyroid cancer and other solid tumors

The cancer stem-like cell (CSC) hypothesis postulates that a small population of cells in a cancer has self-renewal and clonal tumor initiation properties. These cells are responsible for tumor initiation, growth, recurrence and for resistance to chemotherapy and radiation therapy. CSCs can be characterized using markers such as SSEA-1, SSEA-4, CD44, CD24, ALDEFLUOR and others. CSCs form spheres when they are cultured in serum-free condition in low attachment plates and can generate tumors when injected into immune-deficient mice. During epithelial to mesenchymal transition (EMT), cells lose cellular adhesion and polarity and acquire an invasive phenotype. Recent studies have established a relationship between EMT and increased numbers of CSCs in some solid malignancies. Non-coding RNAs such as microRNAs and long non-coding RNAs (lncRNAs) have been shown to have important roles during EMT and some of these molecules also have regulatory roles in the proliferation of CSCs. Specific lncRNAs enhanced cell migration and invasion in breast carcinomas, which was associated with the generation of stem cell properties. The tumor microenvironment of CSCs also has an important role in tumor progression. Recent studies have shown that the interaction between tumor cells and the local microenvironment at the metastatic site leads to the development of premetastatic niche(s) and allows for the proliferation of the metastatic cells during colonization. The role of exosomes in the microenvironment during the EMT program is currently a major area of research. This review examines CSCs and the relationship between EMT and CSCs in solid tumors with emphasis on thyroid CSCs. The role of non-coding RNAs and of the microenvironment in EMT and in tumor progression are also examined. This review also highlights the growing number of studies that show the close association of EMT and CSCs and the role of exosomes and other elements of the tissue microenvironment in CSC metastasis. A better understanding of these mechanisms will lead to more effective targeting of primary and metastatic malignancies.