WNT/β-Catenin Signaling Affects Cell Lineage and Pluripotency-Specific Gene Expression in Bovine Blastocysts: Prospects for Bovine Embryonic Stem Cell Derivation

Blastocyst-like Structures in the Peripheral Retina of Young Adult Beagles

In this immunohistological study on the peripheral retina of 3-year-old beagle dogs, excised retina specimens were immunostained with antibodies against nestin, Oct4, Nanog, Sox2, CDX2, cytokeratin 18 (CK 18), RPE65, and YAP1, as well as hematoxylin and DAPI, two nuclear stains. Our findings revealed solitary cysts of various sizes in the inner retina. Intriguingly, a mass of small round cells with scant cytoplasms was observed in the cavity of small cysts, while many disorganized cells partially occupied the cavity of the large cysts. The small cysts were strongly positive for nestin, Oct4, Nanog, Sox2, CDX2, CK18, and YAP1. RPE65-positive cells were exclusively observed in the tissue surrounding the cysts. Since RPE65 is a specific marker of retinal pigment epithelial (RPE) cells, the surrounding cells of the peripheral cysts were presumably derived from RPE cells that migrated intraretinally. In the small cysts, intense positive staining for nestin, a marker of retinal stem cells, seemed to indicate that they were derived from retinal stem cells. The morphology and positive staining for markers of blastocyst and RPE cells indicated that the small cysts may have formed structures resembling the blastocyst, possibly caused by the interaction between retinal stem cells and migrated RPE cells.

Haploid androgenetic development of bovine embryos reveals imbalanced WNT signaling and impaired cell fate differentiation†

Haploid embryos have contributed significantly to our understanding of the role of parental genomes in development and can be applied to important biotechnology for human and animal species. However, development to the blastocyst stage is severely hindered in bovine haploid androgenetic embryos (hAE). To further our understanding of such developmental arrest, we performed a comprehensive comparison of the transcriptomic profile of morula-stage embryos, which were validated by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) of transcripts associated with differentiation in haploid and biparental embryos. Among numerous disturbances, results showed that pluripotency pathways, especially the wingless-related integration site (WNT) signaling, were particularly unbalanced in hAE. Moreover, transcript levels of KLF4, NANOG, POU5F1, SOX2, CDX2, CTNNBL1, AXIN2, and GSK3B were noticeably altered in hAE, suggesting disturbance of pluripotency and canonical WNT pathways. To evaluate the role of WNT on hAE competence, we exposed early Day-5 morula stage embryos to the GSK3B inhibitor CHIR99021. Although no alterations were observed in pluripotency and WNT-related transcripts, exposure to CHIR99021 improved their ability to reach the blastocysts stage, confirming the importance of the WNT pathway in the developmental outcome of bovine hAE.

Transcriptome changes associated with elongation of bovine conceptuses II: Differentially expressed transcripts in the endometrium on day 17 after insemination

The objective was to characterize endometrial transcriptome on d 17 of gestation in dairy cows according to conceptus length. Nonlactating Holstein cows (n = 48) were slaughtered 17 d after AI and the uterine horn ipsilateral to the corpus luteum (CL) was flushed with saline solution. Recovered conceptuses were classified as small (1.2-6.9 cm; n = 9), medium (10.5-16.0 cm; n = 9), or large (18.0-26.4 cm; n = 10). Samples of intercaruncular endometrium dissected from the caudal, intermediate, and cranial portions of the uterine horn ipsilateral to the pregnancy were pooled for analyses. Total mRNA was extracted from endometrial tissue and subjected to transcriptome analyses using the Affymetrix Gene Chip Bovine array. Data were normalized using the GCRMA method and analyzed by robust regression using the Linear Models for Microarray library within Bioconductor in R. Transcripts with P ≤ 0.05 after adjustment for false discovery rate and fold change ≥1.5 were considered differentially expressed. Functional analyses were conducted using the Ingenuity Pathway Analysis platform. Comparisons between endometria of cows carrying large versus small (LvsS), large versus medium (LvsM), and medium versus small (MvsS) conceptuses yielded a total of 235, 21, and 94 differentially expressed transcripts, respectively. Top canonical pathways included the antigen presentation pathway and Th1/Th2 activation pathways, both for LvsS and MvsS. Interferon-α and -γ were identified as activated upstream regulators, primarily based on differently expressed transcripts such as IDO1, ISG20, WARS, LGALS9, IFI44, and PSMB9 (LvsS and MvsS). For LvsS, regulator analyses revealed predicted activation of FOXO1, IFN, NFACTC2, IL-12, IL-6, and IL-18, whereas it depicted inhibition of IL10RA and ZBTB1. Changes in these regulators were associated with a downstream activation of leukocytes, as well as quantity and expansion of T lymphocytes. Canonical pathways associated with the comparison LvsM included cell cycle G2/M DNA damage checkpoint regulation, cell cycle control of chromosomal replication. Moreover, tretinoin was predicted, as activated in upstream analysis for the same comparison. In conclusion, most of the differently expressed transcripts in the endometrium on d 17 of gestation were identified between cows carrying small conceptuses compared with counterparts carrying medium and large conceptuses and were involved with pathways associated with modulation of the immune response.

Transcriptome changes associated with elongation of bovine conceptuses I: Differentially expressed transcripts in the conceptus on day 17 after insemination

The objective was to characterize transcriptome changes associated with elongation in bovine conceptuses during preimplantation stages. Nonlactating Holstein cows were euthanized 17 d after artificial insemination (AI) and the uterine horn ipsilateral to the CL was flushed with saline solution. Recovered conceptuses were classified as small (1.2 to 6.9 cm; n = 9), medium (10.5 to 16.0 cm; n = 9), or large (18.0 to 26.4 cm; n = 10). Total mRNA was extracted and subjected to transcriptome analyses using the Affymetrix Gene Chip Bovine array. Data were normalized using the GCRMA method and analyzed by robust regression using the Linear Models for Microarray library within Bioconductor in R. Transcripts with P ≤ 0.05 after adjustment for false discovery rate and fold change ≥1.5 were considered differentially expressed. Functional analyses were conducted using the Ingenuity Pathway Analysis platform. Comparisons between large versus small (LvsS), large versus medium (LvsM), and medium versus small (MvsS) conceptuses yielded a total of 634, 240, and 63 differentially expressed transcripts, respectively. Top canonical pathways of known involvement with embryo growth that were upregulated in large conceptuses included actin cytoskeleton (LvsS), integrin signaling (LvsS and LvsM), ephrin receptor (LvsS), mesenchymal transition by growth factor (LvsM), and regulation of calpain protease (LvsS). Transcripts involved with lipid metabolism pathways (LXR/RXR, FXR/RXR, hepatic fibrosis) were associated with the LvsS and LvsM, and some transcripts such as APOC2, APOH, APOM, RARA, RBP4, and PPARGC1A, were involved in these pathways. An overall network summary associated biological downstream effects of invasion of cells, proliferation of embryonic cells, and inhibition of organismal death in the LvsS. In conclusion, differently expressed transcripts in the LvsS comparison were associated with the cell growth, adhesion, and organismal development, although part of these findings could be attributed to differences in circulatory concentrations of progesterone of the cows that bore large and small conceptuses. The large and medium conceptuses developed under similar concentrations of progesterone and presented 240 differently expressed transcripts, associated with cell differentiation, metabolite regulation, and other biological processes.

Sox2 levels regulate the chromatin occupancy of WNT mediators in epiblast progenitors responsible for vertebrate body formation

WNT signalling has multiple roles. It maintains pluripotency of embryonic stem cells, assigns posterior identity in the epiblast and induces mesodermal tissue. Here we provide evidence that these distinct functions are conducted by the transcription factor SOX2, which adopts different modes of chromatin interaction and regulatory element selection depending on its level of expression. At high levels, SOX2 displaces nucleosomes from regulatory elements with high-affinity SOX2 binding sites, recruiting the WNT effector TCF/β-catenin and maintaining pluripotent gene expression. Reducing SOX2 levels destabilizes pluripotency and reconfigures SOX2/TCF/β-catenin occupancy to caudal epiblast expressed genes. These contain low-affinity SOX2 sites and are co-occupied by T/Bra and CDX. The loss of SOX2 allows WNT-induced mesodermal differentiation. These findings define a role for Sox2 levels in dictating the chromatin occupancy of TCF/β-catenin and reveal how context-specific responses to a signal are configured by the level of a transcription factor.

Pluripotent Core in Bovine Embryos: A Review

Early development in mammals is characterized by the ability of each cell to produce a complete organism plus the extraembryonic, or placental, cells, defined as pluripotency. During subsequent development, pluripotency is lost, and cells begin to differentiate to a particular cell fate. This review summarizes the current knowledge of pluripotency features of bovine embryos cultured in vitro, focusing on the core of pluripotency genes (OCT4, NANOG, SOX2, and CDX2), and main chemical strategies for controlling pluripotent networks during early development. Finally, we discuss the applicability of manipulating pluripotency during the morula to blastocyst transition in cattle species.

Strategy to Establish Embryo-Derived Pluripotent Stem Cells in Cattle

Stem cell research is essential not only for the research and treatment of human diseases, but also for the genetic preservation and improvement of animals. Since embryonic stem cells (ESCs) were established in mice, substantial efforts have been made to establish true ESCs in many species. Although various culture conditions were used to establish ESCs in cattle, the capturing of true bovine ESCs (bESCs) has not been achieved. In this review, the difficulty of establishing bESCs with various culture conditions is described, and the characteristics of proprietary induced pluripotent stem cells and extended pluripotent stem cells are introduced. We conclude with a suggestion of a strategy for establishing true bESCs.

Pluripotency and Growth Factors in Early Embryonic Development of Mammals: A Comparative Approach

The regulation of early events in mammalian embryonic development is a complex process. In the early stages, pluripotency, cellular differentiation, and growth should occur at specific times and these events are regulated by different genes that are expressed at specific times and locations. The genes related to pluripotency and cellular differentiation, and growth factors that determine successful embryonic development are different (or differentially expressed) among mammalian species. Some genes are fundamental for controlling pluripotency in some species but less fundamental in others, for example, Oct4 is particularly relevant in bovine early embryonic development, whereas Oct4 inhibition does not affect ovine early embryonic development. In addition, some mechanisms that regulate cellular differentiation do not seem to be clear or evolutionarily conserved. After cellular differentiation, growth factors are relevant in early development, and their effects also differ among species, for example, insulin-like growth factor improves the blastocyst development rate in some species but does not have the same effect in mice. Some growth factors influence genes related to pluripotency, and therefore, their role in early embryo development is not limited to cell growth but could also involve the earliest stages of development. In this review, we summarize the differences among mammalian species regarding the regulation of pluripotency, cellular differentiation, and growth factors in the early stages of embryonic development.

A novel Lnc408 maintains breast cancer stem cell stemness by recruiting SP3 to suppress CBY1 transcription and increasing nuclear β-catenin levels

Tumor initiation, development, and relapse may be closely associated with cancer stem cells (CSCs). The complicated mechanisms underlying the maintenance of CSCs are keeping in illustration. Long noncoding RNAs (lncRNAs), due to their multifunction in various biological processes, have been indicated to play a crucial role in CSC renewal and stemness maintenance. Using lncRNA array, we identified a novel lncRNA (named lnc408) in epithelial-mesenchymal transition-related breast CSCs (BCSCs). The lnc408 is high expressed in BCSCs in vitro and in vivo. The enhanced lnc408 is critical to BCSC characteristics and tumorigenesis. Lnc408 can recruit transcript factor SP3 to CBY1 promoter to serve as an inhibitor in CBY1 transcription in BCSCs. The high expressed CBY1 in non-BCSC interacts with 14-3-3 and β-catenin to form a ternary complex, which leads a translocation of the ternary complex into cytoplasm from nucleus and degradation of β-catenin in phosphorylation-dependent pattern. The lnc408-mediated decrease of CBY1 in BCSCs impairs the formation of 14-3-3/β-catenin/CBY1 complex, and keeps β-catenin in nucleus to promote CSC-associated CD44, SOX2, Nanog, Klf4, and c-Myc expressions and contributes to mammosphere formation; however, restoration of CBY1 expression in tumor cells reduces BCSC and its enrichment, thus lnc408 plays an essential role in maintenance of BCSC stemness. In shortly, these findings highlight that the novel lnc408 functions as an oncogenic factor by recruiting SP3 to inhibit CBY1 expression and β-catenin accumulation in nucleus to maintain stemness properties of BCSCs. Lnc408-CBY1-β-catenin signaling axis might serve as a new diagnostic and therapeutic target for breast cancer.

Wnt/β-catenin Pathway-Mediated PPARδ Expression during Embryonic Development Differentiation and Disease

The Wnt/β-catenin signaling pathway plays a crucial role in early embryonic development. Wnt/β-catenin signaling is a major regulator of cell proliferation and keeps embryonic stem cells (ESCs) in the pluripotent state. Dysregulation of Wnt signaling in the early developmental stages causes several hereditary diseases that lead to embryonic abnormalities. Several other signaling molecules are directly or indirectly activated in response to Wnt/β-catenin stimulation. The crosstalk of these signaling factors either synergizes or opposes the transcriptional activation of β-catenin/Tcf4-mediated target gene expression. Recently, the crosstalk between the peroxisome proliferator-activated receptor delta (PPARδ), which belongs to the steroid superfamily, and Wnt/β-catenin signaling has been reported to take place during several aspects of embryonic development. However, numerous questions need to be answered regarding the function and regulation of PPARδ in coordination with the Wnt/β-catenin pathway. Here, we have summarized the functional activation of the PPARδ in co-ordination with the Wnt/β-catenin pathway during the regulation of several aspects of embryonic development, stem cell regulation and maintenance, as well as during the progression of several metabolic disorders.

Livestock pluripotency is finally captured in vitro

Pluripotent stem cells (PSCs) have demonstrated great utility in improving our understanding of mammalian development and continue to revolutionise regenerative medicine. Thanks to the improved understanding of pluripotency in mice and humans, it has recently become feasible to generate stable livestock PSCs. Although it is unlikely that livestock PSCs will be used for similar applications as their murine and human counterparts, new exciting applications that could greatly advance animal agriculture are being developed, including the use of PSCs for complex genome editing, cellular agriculture, gamete generation and invitro breeding schemes.

Common principles of early mammalian embryo self-organisation

Pre-implantation mammalian development unites extreme plasticity with a robust outcome: the formation of a blastocyst, an organised multi-layered structure ready for implantation. The process of blastocyst formation is one of the best-known examples of self-organisation. The first three cell lineages in mammalian development specify and arrange themselves during the morphogenic process based on cell-cell interactions. Despite decades of research, the unifying principles driving early mammalian development are still not fully defined. Here, we discuss the role of physical forces, and molecular and cellular mechanisms, in driving self-organisation and lineage formation that are shared between eutherian mammals.

WNT signalling supported by MEK/ERK inhibition is essential to maintain pluripotency in bovine preimplantation embryo

Capturing stable embryonic stem cell (ESC) lines from domesticated animals still remains one of the challenges of non-rodent embryology. The stake is high, as stable ESCs derived from species such as cattle present high economic and scientific value. Understanding of the processes leading to the embryonic lineage segregation is crucial to provide species-orientated molecular environment capable of supporting self-renewal and pluripotency. Therefore, the aim of this study was to validate the action of the two core regulatory pathways (WNT and MEK/ERK) during bovine embryo development. In vitro produced bovine embryos were obtained in the presence of inhibitors (i), which enable activation of the WNT pathway (via GSK3i, CHIR99021) and suppression of MEK signalling by PD0325901 in the 2i system and PD184325 and SU5402 in the 3i system. We have followed the changes in the distribution of the key lineage specific markers both at the transcript and protein level. Our results showed that WNT signalling promotes the expression of key inner cell mass (ICM) specific markers in bovine embryos, regardless of the MEK/ERK inhibitor cocktail used. MEK/ERK downregulation is crucial to maintain OCT4 and NANOG expression within the ICM and to prevent their exclusion from the trophectoderm (TE). At the same time, the classical TE marker (CDX2) was downregulated at the mRNA and protein level. As a follow up for the observed pluripotency stimulating effect of the inhibitors, we have tested the potential of the 2i and the 3i culture conditions (supported by LIF) to derive primary bovine ESC lines. As a result, we propose a model in which all of the primary signalling pathways determining embryonic cell fate are active in bovine embryos, yet the requirement for pluripotency maintenance in cattle may differ from the described standards. WNT activation leads to the formation (and stabilisation of the ICM) and MEK/ERK signalling is maintained at low levels. Unlike in the mouse, GATA6 is expressed in both ICM and TE. MEK/ERK signalling affects HP formation in cattle, but this process is activated at the post-blastocyst stage. With regard to self-renewal, 2i is preferable, as 3i also blocks the FGF receptor, what may prevent PI3K signalling, important for pluripotency and self-renewal.

Role of Wnt Signaling During In-Vitro Bovine Blastocyst Development and Maturation in Synergism with PPARδ Signaling

Wnt/β-catenin signaling plays vital role in the regulation of cellular proliferation, migration, stem cells cell renewal and genetic stability. This pathway is crucial during the early developmental process; however, the distinct role of Wnt/β-catenin signaling during pre-implantation period of bovine embryonic development is obscure. Here, we evaluated the critical role of Wnt/β-catenin pathway in the regulation of bovine blastocyst (BL) development and hatching. 6 bromoindurbin-3’oxime (6-Bio) was used to stimulate the Wnt signaling. Treatment with 6-Bio induced the expression of peroxisome proliferator-activated receptor-delta (PPARδ). Interestingly, the PPARδ co-localized with β-catenin and form a complex with TCF/LEF transcription factor. This complex potentiated the expression of several Wnt directed genes, which regulate early embryonic development. Inhibition of PPARδ with selective inhibitor 4-chloro-N-(2-{[5-trifluoromethyl]-2-pyridyl]sulfonyl}ethyl)benzamide (Gsk3787) severely perturbed the BL formation and hatching. The addition of Wnt agonist successfully rescued the BL formation and hatching ability. Importantly, the activation of PPARδ expression by Wnt stimulation enhanced cell proliferation and fatty acid oxidation (FAO) metabolism to improve BL development and hatching. In conclusion, our study provides the evidence that Wnt induced PPARδ expression co-localizes with β-catenin and is a likely candidate of canonical Wnt pathway for the regulation of bovine embryonic development.

From genes to environment in shaping of an embryo: understanding embryonic-extraembryonic interactions at the BSDB autumn meeting in Oxford

The British Society for Developmental Biology Autumn Meeting, held in Oxford in September 2018, was the third in a series of international workshops which have been focussed on development at the extraembryonic-embryonic interface. This workshop, entitled "Embryonic-Extraembryonic Interactions: from Genetics to Environment" built on the two previous workshops held in 2011 (Leuven, Belgium) and 2015 (Göttingen, Germany). This workshop brought together researchers utilising a diverse range of organisms (including both vertebrate and invertebrate species) and a range of experimental approaches to answer core questions in developmental biology. This meeting report highlights some of the major themes emerging from the workshop including an evolutionary perspective as well as recent advances that have been made through the adoption of emerging techniques and technologies.

Inhibitor mediated WNT and MEK/ERK signalling affects apoptosis and the expression of quality related genes in bovine in vitro obtained blastocysts

Culture conditions determine embryo quality, which may be affected on many levels (timing of development, blastomere count, transcripts, metabolite content, apoptosis). Molecular interactions of signalling pathways like MEK/ERK and WNT/β-catenin are critical for cell-to-cell communication and cellular differentiation. Both pathways are important regulators of apoptosis. We have aimed to verify the prolonged effect of MEK/ERK silencing and WNT activation by chemical inhibitors (2i or 3i systems) on bovine IVP embryos. Apoptotic index, total cell count and transcription of embryo quality markers were evaluated. A higher rate of apoptosis was observed in 2i blastocysts, but was not accompanied by changes in transcript content of genes controlling apoptosis (BAX, BCL2, BAK, BAX/BCL2 ratio). Therefore, alternative pathways of apoptotic activation cannot be ruled out. The expression of genes related to embryo quality (HSPA1A, SLC2A1) was not affected. GJA1 transcripts were significantly higher in 3i blastocysts, what indicates a stimulatory effect of the applied inhibitors on cell-to-cell interactions. The lowest mRNA level of the IFNT2 gene was found in 2i embryos. A variation in the SDHA gene transcript was observed (with the highest content in the 3i blastocysts), what may suggest their reduced quality. It may be concluded that the modifications of culture conditions (activation of the WNT and silencing of the MEK/ERK signalling) might alter pathways crucial for embryo development without causing embryonic death.

miR-190 enhances endocrine therapy sensitivity by regulating SOX9 expression in breast cancer

Background

Breast cancer is the most common cancer among women worldwide, and approximately 70% of breast cancers are hormone receptor-positive and express estrogen receptor-α (ERα) or/and progesterone receptor. Therapies targeting ERα have been successfully used in patients with ERα⁺ breast cancer. However, intrinsic or acquired resistance to anti-estrogen therapy presents a major challenge. The Wnt/β-catenin signaling pathway regulates various processes that are important for cancer progression, and emerging evidences have shown a close interaction between Wnt/β-catenin and ERα signaling. miR-190 is also involved in ER signaling and our previous study indicated that miR-190 suppresses breast cancer metastasis.

Methods

The effect of miR-190 on breast cancer anti-estrogen sensitivity was investigated both in vitro and in vivo. The protein expression levels and localization were analyzed by western blotting and immunofluorescence, respectively. Chromatin immunoprecipitation and dual-luciferase reporter assays were used to validate the regulation of the zinc-finger E-box binding homeobox 1/ ERα-miR-190-SRY-related high mobility group box 9 (ZEB1/ERα-miR-190-SOX9) axis.

Results

miR-190 increased the anti-estrogen sensitivity of breast cancer cells both in vitro and in vivo. miR-190 inhibited Wnt/β-catenin signaling by targeting SOX9, and its expression inversely correlated with that of SOX9 in breast cancer samples. Furthermore, ERα and ZEB1 competitively regulated miR-190 expression.

Conclusions

Our data uncover the ZEB1/ERα-miR-190-SOX9 axis and suggest a mechanism by which the Wnt/β-catenin signaling pathway is involved in breast cancer anti-estrogen therapy.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1039-9) contains supplementary material, which is available to authorized users.

High Oct4 predicted worse prognosis of right-sided colon cancer patients

Aim: This present study was aimed to compare the role of Oct4 in left-sided colon cancer (LCC) with right-sided colon cancer (RCC). Patients & methods: One hundred and fifty one pathology specimens, 68 frozen-thawed tumors and cell lines were used to evaluate the role of Oct4 in LCC and RCC through immunohistochemistry, western blot and real-time quantitative PCR. Results: In LCC, positive expression of Oct4 was positively related to differentiation and Dukes stage (p < 0.01). Only in RCC, Oct4 expression was also positively related to lymphatic invasion and survival rates of ‘negative group’ were significantly higher. Conclusion: In summary, Oct4 was related to tumor differentiation and later Dukes stage in colon cancer, and was correlated with invasion of lymphatic only in RCC. In addition, Oct4 was a potential prognostic indicator in RCC.

Changes in chromosome territory position within the nucleus reflect alternations in gene expression related to embryonic lineage specification

Loss of totipotentcy in an early embryo is directed by molecular processes responsible for cell fate decisions. Three dimensional genome organisation is an important factor linking chromatin architecture with stage specific gene expression patterns. Little is known about the role of chromosome organisation in gene expression regulation of lineage specific factors in mammalian embryos. Using bovine embryos as a model we have described these interactions at key developmental stages. Three bovine chromosomes (BTA) that differ in size, number of carried genes, and contain loci for key lineage regulators OCT4, NANOG and CDX2, were investigated. The results suggest that large chromosomes regardless of their gene density (BTA12 gene-poor, BTA5 gene-rich) do not significantly change their radial position within the nucleus. Gene loci however, may change its position within the chromosome territory (CT) and relocate its periphery, when stage specific process of gene activation is required. Trophectoderm specific CDX2 and epiblast precursor NANOG loci tend to locate on the surface or outside of the CTs, at stages related with their high expression. We postulate that the observed changes in CT shape reflect global alternations in gene expression related to differentiation.

Elevated HOTAIR expression associated with cisplatin resistance in non-small cell lung cancer patients

BACKGROUND

This study investigated the mechanism of drug resistance in non-small cell lung cancer (NSCLC) patients. We specifically studied whether long noncoding RNAs influence drug resistance in NSCLC to discover new therapeutic targets to increase the survival rate of drug-resistant NSCLC patients.

METHODS

Tissue samples were collected from NSCLC patients, and total RNA was isolated for assessment of HOTAIR expression and drug resistance status. MTT assays, tumor sphere formation assays, and western blot were performed to cytologically determine the relationship between HOTAIR expression and cisplatin resistance, as well as to elucidate the potential molecular mechanism involved.

RESULTS

HOTAIR expression in tissues of drug-resistant NSCLC patients was higher than that of non-drug-resistant patients. HOTAIR expression was elevated in cisplatin-resistant cell strains (A549/CDDP), and reducing HOTAIR expression increased the sensitivity of A549/CDDP cells to cisplatin. In addition, overexpression of HOTAIR in A549 cells increased resistance to cisplatin. Tumor sphere formation assays showed that the volume of spheres formed by cell strains expressing elevated levels of HOTAIR was greater than that of cell strains with low expression. Western blot experiments showed that elevated expression of HOTAIR upregulated tumor stem cell-related biomarkers and HOTAIR expression was directly related to Klf4 expression.

CONCLUSIONS

Elevated HOTAIR expression is associated with drug resistance in NSCLC patients and is related to Klf4 upregulation, providing a new therapeutic target for drug-resistant NSCLC patients.

Sex differences in response of the bovine embryo to colony-stimulating factor 2

We tested whether gene expression of the bovine morula is modified by CSF2 in a sex-dependent manner and if sex determines the effect of CSF2 on competence of embryos to become blastocysts. Embryos were produced in vitro using X- or Y-sorted semen and treated at Day 5 of culture with 10 ng/mL bovine CSF2 or control. In experiment 1, morulae were collected at Day 6 and biological replicates (n = 8) were evaluated for transcript abundance of 90 genes by RT-qPCR using the Fluidigm Delta Gene assay. Expression of more than one-third (33 of 90) of genes examined was affected by sex. The effect of CSF2 on gene expression was modified by sex (P < 0.05) for five genes (DDX3Y/DDX3X-like, NANOG, MYF6, POU5F1 and RIPK3) and tended (P < 0.10) to be modified by sex for five other genes (DAPK1, HOXA5, PPP2R3A, PTEN and TNFSF8). In experiment 2, embryos were treated at Day 5 with control or CSF2 and blastocysts were collected at Day 7 for immunolabeling to determine the number of inner cell mass (ICM) and trophectoderm (TE) cells. CSF2 increased the percent of putative zygotes that became blastocysts for females, but did not affect the development of males. There was no effect of CSF2 or interaction of CSF2 with sex on the total number of blastomeres in blastocysts or in the number of inner cell mass or trophectoderm cells. In conclusion, CSF2 exerted divergent responses on gene expression and development of female and male embryos. These results are evidence of sexually dimorphic responses of the preimplantation embryo to this embryokine.