Side Population Research Articles

Recent Advances in the Targeting of Head and Neck Cancer Stem Cells

Head and neck squamous cell carcinoma (HNSCC) is a very heterogeneous cancer with a poor overall response to therapy. One of the reasons for this therapy resistance could be cancer stem cells (CSCs), a small population of cancer cells with self-renewal and tumor-initiating abilities. Tumor cell heterogeneity represents hurdles for therapeutic elimination of CSCs. Different signaling pathway activations, such as Wnt, Notch, and Sonic-Hedgehog (SHh) pathways, lead to the expression of several cancer stem factors that enable the maintenance of CSC features. Identification and isolation of CSCs are based either on markers (CD133, CD44, and aldehyde dehydrogenase (ALDH)), side populations, or their sphere-forming ability. A key challenge in cancer therapy targeting CSCs is overcoming chemotherapy and radiotherapy resistance. However, in novel therapies, various approaches are being employed to address this hurdle such as targeting cell surface markers, other stem cell markers, and different signaling or metabolic pathways, but also, introducing checkpoint inhibitors and natural compounds into the therapy can be beneficial.

IL20RB signaling enhances stemness and chemotherapy resistance in pancreatic cancer

ObjectivePancreatic cancer is an aggressive malignancy with high mortality, and cancer cell stemness and related drug resistance are considered important contributors to its poor prognosis. The objective of this study was to identify regulatory targets associated with the maintenance of pancreatic cancer stemness.Materials and MethodsPancreatic tumor samples were collected from patients at Sun Yat-sen University Cancer Center, followed by immunofluorescence analysis. Pancreatic cancer cell lines with Interleukin-20 receptor subunit beta (IL20RB) overexpression and knockdown were established, and clonal formation, spheroid formation and side population cell analysis were conducted. The effects of IL20RB knockdown on the tumor-forming ability of pancreatic cancer cells and chemotherapy resistance in vivo were explored.ResultsIL20RB expression was significantly upregulated in pancreatic cancer tissues, and was correlated with unfavorable prognosis. The IL20RB receptor promotes stemness and chemoresistance in both in vitro and in vivo models of pancreatic cancer. Mechanistically, IL20RB enhances the stemness and chemoresistance of pancreatic cancer by promoting STAT3 phosphorylation, an effect that can be counteracted by a STAT3 phosphorylation inhibitors. Additionally, Interleukin-19 derived from the microenvironment is identified as the primary ligand for IL20RB in mediating these effects.ConclusionOur findings demonstrate that IL20RB plays a crucial role in promoting stemness in pancreatic cancer. This discovery provides a potential therapeutic target for this lethal disease.Graphical abstract

Periostin facilitates ovarian cancer recurrence by enhancing cancer stemness

The lethality of epithelial ovarian cancer (OC) is largely due to a high rate of recurrence and development of chemoresistance, which requires synergy between cancer cells and the tumor microenvironment (TME) and is thought to involve cancer stem cells. Our analysis of gene expression microarray data from paired primary and recurrent OC tissues revealed significantly elevated expression of the gene encoding periostin (POSTN) in recurrent OC compared to matched primary tumors (p = 0.015). Secreted POSTN plays a role in the extracellular matrix, facilitating epithelial cell migration and tissue regeneration. We therefore examined how elevated extracellular POSTN, as we found is present in recurrent OC, impacts OC cell functions and phenotypes, including stemness. OC cells cultured with conditioned media with high levels of periostin (CMPOSTNhigh) exhibited faster migration (p = 0.0044), enhanced invasiveness (p = 0.006), increased chemoresistance (p < 0.05), and decreased apoptosis as compared to the same cells cultured with control medium (CMCTL). Further, CMPOSTNhigh-cultured OC cells exhibited an elevated stem cell side population (p = 0.027) along with increased expression of cancer stem cell marker CD133 relative to CMCTL-cultured cells. POSTN-transfected 3T3-L1 cells that were used to generate CMPOSTNhigh had visibly enhanced intracellular and extracellular lipids, which was also linked to increased OC cell expression of fatty acid synthetase (FASN) that functions as a central regulator of lipid metabolism and plays a critical role in the growth and survival of tumors. Additionally, POSTN functions in the TME were linked to AKT pathway activities. The mean tumor volume in mice injected with CMPOSTNhigh-cultured OC cells was larger than that in mice injected with CMCTL-cultured OC cells (p = 0.0023). Taken together, these results show that elevated POSTN in the extracellular environment leads to more aggressive OC cell behavior and an increase in cancer stemness, suggesting that increased levels of stromal POSTN during OC recurrence contribute to more rapid disease progression and may be a novel therapeutic target. Furthermore, they also demonstrate the utility of having matched primary-recurrent OC tissues for analysis and support the need for better understanding of the molecular changes that occur with OC recurrence to develop ways to undermine those processes.

Acidosis promotes the metastatic colonization of lung cancer via remodeling of the extracellular matrix and vasculogenic mimicry.

Acidosis is a hallmark of the tumor microenvironment caused by the metabolic switch from glucose oxidative phosphorylation to glycolysis. It has been associated with tumor growth and progression; however, the precise mechanism governing how acidosis promotes metastatic dissemination has yet to be elucidated. In the present study, a long‑term acidosis model was established using patient‑derived lung cancer cells, to identify critical components of metastatic colonization via transcriptome profiling combined with both invitro and invivo functional assays, and association analysis using clinical samples. Xenograft inoculates of 1 or 10 acidotic cells mimicking circulating tumor cell clusters were shown to exhibit increased tumor incidence compared with their physiological pH counterparts. Transcriptomics revealed that profound remodeling of the extracellular matrix (ECM) occurred in the acidotic cells, including upregulation of the integrin subunit α‑4 (ITGA4) gene. In clinical lung cancer, ITGA4 expression was found to be upregulated in primary tumors with metastatic capability, and this trait was retained in the corresponding secondary tumors. Expression of ITGA4 was markedly upregulated around the vasculogenic mimicry structures of the acidotic tumors, while acidotic cells exhibited a higher ability of vasculogenic mimicry invitro. Acidosis was also found to induce the enrichment of side population cells, suggesting an enhanced resistance to noxious attacks of the tumor microenvironment. Taken together, these results demonstrated that acidosis actively contributed to tumor metastatic colonization, and novel mechanistic insights into the therapeutic management and prognosis of lung cancer were discussed.

Effect of trichostatin A on biological characteristics of side population cells of cervical cancer cell line (HeLa)

Purpose: To investigate the effect of trichostatin A (TSA) on biological characteristics of side population (SP) cells of cervical cancer cell line (HeLa)Methods: Side population (SP) and NSP cells were obtained from 6th generation of primary cervical cancer cells and cervical cancer cell line (HeLa). Cell surface markers (ATP-binding membrane transporter superfamily G member 2 (ABCG2), CD133, CD43, p63, Ki67, multidrug resistance (MDR) as well as cell cycle phase distribution and apoptosis, were determined. SP cells in HeLa were divided into 3 groups that received TSA at doses of 0.01, 0.05, and 0.2 μM. Untreated cells served as control. Cell growth inhibition rates of different dose groups were compared. SP cells in HeLa were divided into simple irradiation group and combined irradiation group TSA (10 % inhibition concentration (IC10) + irradiation, and values of SP cell survival fraction (SF) of the two groups under different irradiation conditions were compared.Results: The content of SP in HeLa cell line was significantly higher than in cervical cancer tissue (p &gt; 0.05). There were no significant differences in expression levels of ABCG2, CD133, CD43, p63, Ki67, and MDR, as well as G0/G1, S, and G2/M phase distributions and apoptosis rate between HeLa cell line and cervical cancer tissue (p &gt; 0.05). On the 3rd, 5th, and 7th day, SF value of SP cells was significantly higher in NSP cells (p &gt; 0.05). With increasing concentration of TSA, SF value of NSP cells gradually decreased, while that of SP cells did not change significantly.Conclusion: Cervical cancer cell line (HeLa) contains SP cells which have biological characteristics of tumor stem cells. Moreover, TSA exerts good cytotoxicity and radio-sensitization effect on SP cells.

Ascl1 and Ngn2 convert mouse embryonic stem cells to neurons via functionally distinct paths

Ascl1 and Ngn2, closely related proneural transcription factors, are able to convert mouse embryonic stem cells into induced neurons. Despite their similarities, these factors elicit only partially overlapping transcriptional programs, and it remains unknown whether cells are converted via distinct mechanisms. Here we show that Ascl1 and Ngn2 induce mutually exclusive side populations by binding and activating distinct lineage drivers. Furthermore, Ascl1 rapidly dismantles the pluripotency network and installs neuronal and trophoblast cell fates, while Ngn2 generates a neural stem cell-like intermediate supported by incomplete shutdown of the pluripotency network. Using CRISPR-Cas9 knockout screening, we find that Ascl1 relies more on factors regulating pluripotency and the cell cycle, such as Tcf7l1. In the absence of Tcf7l1, Ascl1 still represses core pluripotency genes but fails to exit the cell cycle. However, overexpression of Cdkn1c induces cell cycle exit and restores the generation of neurons. These findings highlight that cell type conversion can occur through two distinct mechanistic paths, even when induced by closely related transcription factors.

Characterising side population genes in placentas from patients with preeclampsia and/or fetal growth restriction.

Characterising side population genes in placentas from patients with preeclampsia and/or fetal growth restriction.

BSBM-22 CHARACTERIZATION OF CIRCULATORY SHEAR STRESS-INDUCED MOLECULAR CHANGES IN LUNG ADENOCARCINOMA CELLS AND IMPLICATIONS IN BRAIN METASTASIS

Abstract INTRODUCTION Lung cancer is the most common tumor to metastasize to the brain, as 40% of patients develop brain metastasis (BM). Once diagnosed, survival is only 6.5-10 months. A potential target to prevent BM is circulating tumor cells (CTCs). The mechanisms that mediate a CTCs adaptation to the harsh environment of circulation and BM have not been elucidated. We have demonstrated that primary lung cancer cells (LCCs) subjected to circulation have increased migration across brain endothelial cell monolayers, increased side population, and decrease survival in rodents when injected intracardially vs plated controls. METHODS We engineered a microfluidic device capable of subjecting tumor cells to prolonged circulatory shear stress (CSS) that allows the isolation/modeling of CTC-like cells. Primary LCCs (A549, H1563) were subjected to circulation, suspension, or plated (2D) for 72h as controls. At this time point, LCCs were collected, and total mRNA was extracted. Samples were submitted for RNA sequencing. Weighted gene co-expression network analysis (WCGNA) and Ingenuity Pathway Analysis were performed. (FC &amp;gt;2 and p-value &amp;lt;0.05). RESULTS Transcriptomic analysis indicates that cells subjected to CSS activate specific gene networks involved in cell survival, migration, invasion, adhesion of tumor cells, and cytoskeletal reorganization (z-score: &amp;gt;2, p-value: 0.05). Canonical pathways in CTCs included ILK-signaling and Xenobiotic Metabolism. LCCs exposed to CSS had increased expression of multidrug resistance pumps ABCC2, ABCF2 (P:&amp;lt;0.001), and side population on flow cytometry (P: &amp;lt;0.05). The top differentially expressed genes in CTC-like cells (MMP1, ANGPTL4, and CEMIP) were involved in the invasion, angiogenesis, and pre-metastatic niche (PMN) formation of BM. CONCLUSION LCCs that survive CSS have increased expression of genes associated with migration, invasion, and chemoresistance compared to 2D controls. Targeting genes in CTCs that mediate survival and preparation of the PMN may be useful in preventing BM.

Interferon-Alpha Decreases Cancer Stem Cell Properties and Modulates Exosomes in Malignant Melanoma.

Malignant melanoma (MM) can spread to other organs and is resistant in part due to the presence of cancer stem cell subpopulations (CSCs). While a controversial high dose of interferon-alpha (IFN-α) has been used to treat non-metastatic high-risk melanoma, it comes with undesirable side effects. In this study, we evaluated the effect of low and high doses of IFN-α on CSCs by analyzing ALDH activity, side population and specific surface markers in established and patient-derived primary cell lines. We also assessed the clonogenicity, migration and tumor initiation capacities of IFN-α treated CSCs. Additionally, we investigated genomic modulations related to stemness properties using microRNA sequencing and microarrays. The effect of IFN-α on CSCs-derived exosomes was also analyzed using NanoSight and liquid chromatography (LC-HRMS)-based metabolomic analysis, among others. Our results showed that even low doses of IFN-α reduced CSC formation and stemness properties, and led to a significant decrease in the ability to form tumors in mice xenotransplants. IFN-α also modulated the expression of genes and microRNAs involved in several cancer processes and metabolomics of released exosomes. Our work suggests the utility of low doses of interferon, combined with the analysis of metabolic biomarkers, as a potential clinical approach against the aggressiveness of CSCs in melanoma.

Endometrial and placental stem cells in successful and pathological pregnancies.

The endometrium is a dynamic tissue that undergoes extensive remodeling during the menstrual cycle and further gets modified during pregnancy. Different kinds of stem cells are reported in the endometrium. These include epithelial stem cells, endometrial mesenchymal stem cells, side population stem cells, and very small embryonic-like stem cells. Stem cells are also reported in the placenta which includes trophoblast stem cells, side population trophoblast stem cells, and placental mesenchymal stem cells. The endometrial and placental stem cells play a pivotal role in endometrial remodeling and placental vasculogenesis during pregnancy. The dysregulation of stem cell function is reported in various pregnancy complications like preeclampsia, fetal growth restriction, and preterm birth. However, the mechanisms by which it does so are yet elusive. Herein, we review the current knowledge of the different type of stem cells involved in pregnancy initiation and also highlight how their improper functionality leads to pathological pregnancy.

Connexin 43 gap junction affects survival and drug resistance of multiple myeloma side population cells.

Drug resistance remains a major challenge for multiple myeloma (MM) treatment, and side population (SP) cells may play a key role in this resistance. The function of connexin 43 (Cx43)-mediated gap junction intercellular communication (GJ-IC) in MM cells is poorly understood. Bone marrow mesenchymal stem cells (BMSCs) from different sources were isolated and cultured. SP cells of MM cell line RPMI 8266 were separated by flow cytometry. Real-time reverse transcriptase-polymerase chain reaction and Western blot were used to detect Cx43 mRNA and protein expression in BMSCs, RPMI 8266 and SP cells from different sources. The effects of BMSCs from different sources on SP cell cycle, in vitro colony formation ability, stem cell-related gene expression and drug resistance, and the addition of 18α glycyrrhetinic acid (18αGA) as a pathway inhibitor were observed. Here, we demonstrate that MM cells expressed Cx43 and contained a high percentage of SP cells. We observed an increase in the survival and proliferative capacity of SP cells compared with RPMI 8226 cells, but treatment with 18αGA decreased SP cell survival and proliferation (all P<0.05). MM cells were sensitive to dexamethasone- and bortezomib-induced apoptosis; however, this sensitivity was significantly decreased when MM cells were co-cultured with BMSCs, and 18αGA partly recovered this cytotoxicity (all P<0.05). Collectively, our data suggest that GJ-IC between BMSCs and MM cells is one of the important regulatory mechanisms underlying MM cells survival, proliferation, and drug sensitivity.

Aluminium phthalocyanine–mediated photodynamic therapy promotes antitumour activity in oesophageal cancer stem cells.

e15194 Background: Photodynamic therapy (PDT), a non-invasive treatment modality, has emerged as an effective treatment measure for various cancers, including oesophageal cancer. PDT has attracted much attention in the field of oncology due to its low toxicity profile and the selective accumulation of the photoactivated agent in the tumour cells. However, the therapeutic effect of Aluminium (III) Phthalocyanine Chloride Tetra sulfonic Acid (AlPcS4Cl) mediated PDT on oesophageal CSCs is limited. In this study, we evaluated the cellular localization of AlPcS4Cl and its PDT anticancer effects on oesophageal CSCs. Methods: An in vitro experimental design was employed in this study. Oesophageal cancer (HKESC-1 cells) was grown, and the CSCs were isolated using the magnetic-activated cell sorting (MACS). The isolated CSCs were characterised using a flow cytometry, Hoechst efflux side population test, and immunofluorescence. The CSCs were maintained in a serum-free culture medium and incubated at 37° C, 5% CO2 and 85% humidity. The cells were grouped into control and experimental groups. The CSCs received two-fold increasing concentrations of AlPcS4Cl and were exposed to irradiation at 673.2nm wavelength using a diode laser. After 24 hours post-PDT, the anticancer activities of AlPcS4Cl on oesophageal CSCs were examined. The MTT cell viability assay was used to determine the 50% inhibitory concentration (IC50), light microscopy for morphological changes, and adenosine triphosphate (ATP) assay for cell proliferation, lactate dehydrogenase (LDH) assay for cellular toxicity. While cellular localization of AlPcS4Cl was examined using fluorescent microscopy. All experimental and control cells were conducted in six biological replicates (n = 6). Results: Results were compiled, and statistical analysis was performed using GraphPad Prism (v5). The mean values of experimental groups were compared with the mean value of the control cells. One-way ANOVA was employed, and a p-value of less than 0.05 was considered statistically significant. Findings from cellular localization showed that the AlPcS4Cl is localized in the mitochondria and lysosomes, indicating a probable cellular death pathway. The dose-response of AlPcS4Cl on oesophageal CSCs showed an IC50 value of 4µM, suggesting the photosensitizer is efficient for the treatment of CSCs at low concentrations. The CSCs exposed to PDT showed remarkable morphological distortion, high cytotoxic activity, decreased viable cells and significant antiproliferative potential. Conclusions: This study showed that AlPcS4Cl promote PDT anticancer effects on oesophageal CSCs and could serve as an efficient therapeutic option for eradicating oesophageal CSCs.

Side population cells derived from hUCMSCs and hPMSCs could inhibit the malignant behaviors of Tn+ colorectal cancer cells from modifying their O-glycosylation status

BackgroundCosmc (C1GalT1C1) mutation could cause aberrant O-glycosylation and result in expression of Tn antigen on the surface of tumor cells (Tn+ cells), which is associated with the metastasis and prognosis of cancer progression. Mesenchymal stem cells (MSCs) could participate in immunoregulation, tissue damage repair, and tumor inhibition and be seen as an ideal candidate for tumor therapy due to their inherent capacity to migrate to tumor sites. However, their therapeutic effectiveness in different tumors is inconsistent and still controversial. Of note, emerging data reveal that side population (SP) cells have a stronger multilineage developmental potential than main population cells and can function as stem/progenitor cells. The effect of SP cells derived from MSCs on the biological behaviors and the O-glycosylation status of tumor cells remains unclear.MethodsSP cells were isolated from human umbilical cord MSCs (hUCMSCs) and human placenta MSCs (hPMSCs). Tn+ cells (LS174T-Tn+ and HT-29-Tn+ cells) and matching Tn− cells (LS174T-Tn− and HT-29-Tn− cells) were isolated from human colorectal cancer cell (CRC) lines LS174T and HT-29 by immune magnetic beads. The proliferation, migration, apoptosis, Tn antigen expression, and O-glycome in Tn+ and Tn− CRC cells before and after co-cultured with SP-MSCs were detected using real-time cell Analysis (RTCA), flow cytometry (FCM), and cellular O-glycome reporter/amplification (CORA), respectively. Cosmc protein and O-glycosyltransferase (T-synthase and C3GnT) activity in CRC cells were, respectively, assessed using western blotting and fluorescence method.ResultsBoth SP cells derived from hUCMSCs and hPMSCs could inhibit proliferation and migration, promote apoptosis of CRC cells, significantly reduce Tn antigen expression on Tn+ CRC cells, generate new core 1-, 2-, and 3-derived O-glycans, increase T-synthase and C3GnT activity, and elevate the levels of Cosmc and T-synthase protein.ConclusionSP-hUCMSCs and SP-hPMSCs could inhibit proliferation and migration and promote apoptosis of Tn+ CRC cells via increasing O-glycosyltransferase activity to modify O-glycosylation status, which further adds a new dimension to the treatment of CRC.

New findings on the action of hypericin in hypoxic cancer cells with a focus on the modulation of side population cells

The presence of key hypoxia regulators, namely, hypoxia-inducible factor (HIF)-1α or HIF-2α, in tumors is associated with poor patient prognosis. Hypoxia massively activates several genes, including the one encoding the BCRP transporter that proffers multidrug resistance to cancer cells through the xenobiotic efflux and is a determinant of the side population (SP) associated with cancer stem-like phenotypes. As natural medicine comes to the fore, it is instinctive to look for natural agents possessing powerful features against cancer resistance. Hypericin, a pleiotropic agent found in Hypericum plants, is a good example as it is a BCRP substrate and potential inhibitor, and an SP and HIF modulator. Here, we showed that hypericin efficiently accumulated in hypoxic cancer cells, degraded HIF-1/2α, and decreased BCRP efflux together with hypoxia, thus diminishing the SP population. On the contrary, this seemingly favorable result was accompanied by the stimulated migration of this minor population that preserved the SP phenotype. Because hypoxia unexpectedly decreased the BCRP level and SP fraction, we compared the SP and non-SP proteomes and their changes under hypoxia in the A549 cell line. We identified differences among protein groups connected to the epithelial–mesenchymal transition, although major changes were related to hypoxia, as the upregulation of many proteins, including serpin E1, PLOD2 and LOXL2, that ultimately contribute to the initiation of the metastatic cascade was detected. Altogether, this study helps in clarifying the innate and hypoxia-triggered resistance of cancer cells and highlights the ambivalent role of natural agents in the biology of these cells.

A transverse colon lipoma complicated with an adenoma is successfully and safely resected en bloc by endoscopic mucosal resection during water immersion

The B-cell-specific Moloney murine leukemia virus integration site 1 (BMI-1) is associated with the progression of gastric cancer (GC). However, its role in drug resistance of gastric cancer stem cell (GCSC) remains unclear. This study aimed to explore the biological function of BMI-1 in GC cells and its role in drug resistance of GCSCs.We assessed BMI-1 expression in the GEPIA database and in our collected samples from patients with GC. We silenced BMI-1 using siRNA to study the cell proliferation and migration of GC cells. We also used Hoechst 33342 staining to verify the effect of adriamycin (ADR) on side population (SP) cells, and measured the effects of BMI-1 on the expression of N-cadherin, E-cadherin, and drug-resistance-related proteins (multidrug resistance mutation 1 and lung resistance-related protein). Finally, we analyzed BMI-1-related proteins uing the STRING and GEPIA databases.BMI-1 mRNA was upregulated in GC tissues and cell lines, especially in MKN-45 and HGC-27 cells. Silencing BMI-1 reduced the proliferation and migration of GC cells. Knocking down BMI-1 significantly decreased epithelial-mesenchymal transition progression, expression levels of drug-resistant proteins, and the number of SP cells in ADR-treated GC cells. Bioinformatics analysis showed that EZH2, CBX8, CBX4, and SUZ12 were positively correlated with BMI-1 in GC tissues.Our study demonstrates that BMI-1 affects the cellular activity, proliferation, migration, and invasion of GC cells. Silencing the BMI-1 gene significantly reduces the number of SP cells and the expression of drug-resistant proteins in ADR-treated GC cells. We speculate that inhibition of BMI-1 increases the drug resistance of GC cells by affecting GCSCs, and that EZH2, CBX8, CBX4, and SUZ12 may participate in BMI-1-induced enhancement of GCSC-like phenotype and viability.

Combined GSK-3β and MEK inhibitors modulate the stemness and radiotherapy sensitivity of cervical cancer stem cells through the Wnt signaling pathway

Cancer stem cells (CSCs) are the basis of cancer and lead to the recurrence and metastasis of cervical cancer. The aim of this study was to investigate the effects of antineoplastic agents on the stemness and radiotherapy sensitivity of cervical CSCs. Side population (SP) and non-side population (NSP) cells from the SiHa cervical cancer cell line were separated using flow cytometry. The cell spheroidization, proliferation, and subcutaneous tumor formation abilities of SP cells were stronger than those of NSP cells, and cervical CSC marker expressions increased in SP cells. The proliferation, anti-apoptosis and migration of SP cells under ionizing radiation were higher than those of SiHa cells. GSK-3β and/or MEK inhibitors can increase the proliferation, migration and anti-apoptosis of SP cells, and CSC marker expressions. The Wnt pathway inhibitor decreased CSC stemness maintenance by combination of GSK-3β and MEK inhibitors. Injection of GSK-3β and MEK inhibitors under ionizing radiation promoted tumor growth and activated downstream factor expressions in the Wnt signaling pathway in vivo. This study demonstrated that combining GSK-3β and MEK inhibitors can activate Wnt signaling pathway in cervical CSCs, thereby affecting their stemness maintenance and radiotherapy sensitivity.

Temporal and spatial variability in population traits of an intertidal fucoid reveals local-scale climatic refugia

Global change is imposing significant losses in the functional traits of marine organisms. Although areas of climatic refugia ameliorate local conditions and help them to persist, the extent to which mesoscale effects contribute for intraregional variability on population traits and conservation is uncertain. Here we assess patterns of conservation status of Fucus guiryi, the main intertidal habitat-forming seaweed in the Strait of Gibraltar (southern Spain and northern Morocco). We investigated the demography, reproductive phenology, and morphology at northern and southern side populations. Population traits were compared seasonally within populations from each side, and at spatial scale in early summer 2019. In the last decade three populations became extinct; two marginal populations had dispersed individuals with a narrower fertility season and miniaturized individuals below 3 cm; and five populations showed variable density and cover with more than 20% of reproductive individuals over the seasons. Highest density, cover, morphology, and reproductive potential was detected at one population from each side, suggesting local-scale climatic refugia in upwelling areas located inside marine protected areas. Southern recruits were more warm-tolerant but grew less at colder conditions than northern ones, revealing a mesoscale heterogeneity in thermal affinities. This study evidenced functional losses and distinct reproductive strategies experienced by F. guiryi at peripheral locations and urges to prioritize its conservation and restoration at contemporary climatic refugia.

The presence of stem cells in ovarian cancer: a review

Ovarian cancer is one of the deadly gynecological malignancies. The disease has usually difficult to detect at the early stage as there are only a few specific symptoms and not many screening methods, thus patients usually come in an advanced and metastatic stage of the disease. Initial therapy for the disease includes surgery to remove the tumor, then followed by chemotherapy. This therapy shows a promising result at first until some sign of reoccurrence starts to show. One of the main reasons is thought to be the presence of a small subset of cells called cancer stem cells (CSCs). These cells may escape from the initial therapy, and due to the CSCs' ability to self-renew, grow into various lineages, and multiply widely. There are multiple efforts done to isolate and identify this subset cell, such as identifying the specific antigen in the cell surface, using Side Population, the ability of CSCs to form floating spheres in serum-free media, and the level of ALDH expression. Such methods have been performed together to identify purely cancer stem cells from the malignancy. The ability of the cell to produce new tumors in immuno-deficient animals, however, is the gold standard for identifying CSC, according to the current study. This review will discuss several methods that have been used to isolate cancer stem cells and prove the stemness of these cells by injecting them into immuno-deficient mice. Cancer stem cells also can avoid the effect of chemotherapy. Several things contribute to this ability. This review there will discuss methods that have been several things that make it possible to be able to escape chemotherapy drugs. By understanding these mechanisms, hopefully, new therapy modalities will be developed and specifically targeted, so that can be used to treat malignancies more effectively.

B-cell-specific Moloney murine leukemia virus integration site 1 knockdown impairs adriamycin resistance of gastric cancer cells

Background and study aimsThe B-cell-specific Moloney murine leukemia virus integration site 1 (BMI-1) is associated with the progression of gastric cancer (GC). However, its role in drug resistance of gastric cancer stem cell (GCSC) remains unclear. This study aimed to explore the biological function of BMI-1 in GC cells and its role in drug resistance of GCSCs. Patients and methodsWe assessed BMI-1 expression in the GEPIA database and in our collected samples from patients with GC. We silenced BMI-1 using siRNA to study the cell proliferation and migration of GC cells. We also used Hoechst 33342 staining to verify the effect of adriamycin (ADR) on side population (SP) cells, and measured the effects of BMI-1 on the expression of N-cadherin, E-cadherin, and drug-resistance-related proteins (multidrug resistance mutation 1 and lung resistance-related protein). Finally, we analyzed BMI-1-related proteins uing the STRING and GEPIA databases. ResultsBMI-1 mRNA was upregulated in GC tissues and cell lines, especially in MKN-45 and HGC-27 cells. Silencing BMI-1 reduced the proliferation and migration of GC cells. Knocking down BMI-1 significantly decreased epithelial-mesenchymal transition progression, expression levels of drug-resistant proteins, and the number of SP cells in ADR-treated GC cells. Bioinformatics analysis showed that EZH2, CBX8, CBX4, and SUZ12 were positively correlated with BMI-1 in GC tissues. ConclusionOur study demonstrates that BMI-1 affects the cellular activity, proliferation, migration, and invasion of GC cells. Silencing the BMI-1 gene significantly reduces the number of SP cells and the expression of drug-resistant proteins in ADR-treated GC cells. We speculate that inhibition of BMI-1 increases the drug resistance of GC cells by affecting GCSCs, and that EZH2, CBX8, CBX4, and SUZ12 may participate in BMI-1-induced enhancement of GCSC-like phenotype and viability.

Cancer Stem Cells as the Key to Cancer: Special Emphasis on Prostate Cancer

Recent research into cancer stem cells has refined our knowledge of the origins, maintenance, and progression of cancer. The characteristics of tumor initiating cells and the stem-like properties of tumor side populations that appear to be responsible for tumor maintenance and metastasis have given insights into potential targets for the elimination of treatment-resistant and residual tumor cells. These insights have also provided inroads to understanding and preventing invasive and metastatic progression of cancer. In this review, we discuss recent advancements in understanding of tumor initiating cells and cancer stem cells and their implications on cancer pathobiology and treatment. The role of tumor initiating cell phenotypes on routes of metastasis and the use of stemness markers to guide prognosis and treatment are also discussed. Particular emphasis sections are included that focus on the role of stemness in the pathobiology and treatment of prostate cancer. Of particular interest is the correlation of stemness with decreased androgen receptor expression and resistance to anti-androgen therapy. The overview provided herein represents a primer for the understanding of current knowledge regarding cancer stem cells and their clinical implications in prostate and other cancer types.