Regulation Of Sox2 Research Articles

Mutant NR5A1/SF-1 in patients with disorders of sex development shows defective activation of the SOX9 TESCO enhancer.

Nuclear receptor subfamily 5 group A member 1/Steroidogenic factor 1 (NR5A1; SF-1; Ad4BP) mutations cause 46,XY disorders of sex development (DSD), with phenotypes ranging from developmentally mild (e.g., hypospadias) to severe (e.g., complete gonadal dysgenesis). The molecular mechanism underlying this spectrum is unclear. During sex determination, SF-1 regulates SOX9 (SRY [sex determining region Y]-box 9) expression. We hypothesized that SF-1 mutations in 46,XY DSD patients affect SOX9 expression via the Testis-specific Enhancer of Sox9 core element, TESCO. Our objective was to assess the ability of 20 SF-1 mutants found in 46,XY DSD patients to activate TESCO. Patient DNA was sequenced for SF-1 mutations and mutant SF-1 proteins were examined for transcriptional activity, protein expression, sub-cellular localization and in silico structural defects. Fifteen of the 20 mutants showed reduced SF-1 activation on TESCO, 11 with atypical sub-cellular localization. Fourteen SF-1 mutants were predicted in silico to alter DNA, ligand or cofactor interactions. Our study may implicate aberrant SF-1-mediated transcriptional regulation of SOX9 in 46,XY DSDs.

The BRG1/SOX9 axis is critical for acinar cell-derived pancreatic tumorigenesis.

Chromatin remodeler Brahma related gene 1 (BRG1) is silenced in approximately 10% of human pancreatic ductal adenocarcinomas (PDAs). We previously showed that BRG1 inhibits the formation of intraductal pancreatic mucinous neoplasm (IPMN) and that IPMN-derived PDA originated from ductal cells. However, the role of BRG1 in pancreatic intraepithelial neoplasia-derived (PanIN-derived) PDA that originated from acinar cells remains elusive. Here, we found that exclusive elimination of Brg1 in acinar cells of Ptf1a-CreER; KrasG12D; Brg1fl/fl mice impaired the formation of acinar-to-ductal metaplasia (ADM) and PanIN independently of p53 mutation, while PDA formation was inhibited in the presence of p53 mutation. BRG1 bound to regions of the Sox9 promoter to regulate its expression and was critical for recruitment of upstream regulators, including PDX1, to the Sox9 promoter and enhancer in acinar cells. SOX9 expression was downregulated in BRG1-depleted ADMs/PanINs. Notably, Sox9 overexpression canceled this PanIN-attenuated phenotype in KBC mice. Furthermore, Brg1 deletion in established PanIN by using a dual recombinase system resulted in regression of the lesions in mice. Finally, BRG1 expression correlated with SOX9 expression in human PDAs. In summary, BRG1 is critical for PanIN initiation and progression through positive regulation of SOX9. Thus, the BRG1/SOX9 axis is a potential target for PanIN-derived PDA.

SOX2 regulation by hedgehog signaling controls adult lingual epithelium homeostasis.

Adult tongue epithelium is continuously renewed from epithelial progenitor cells, a process that requires hedgehog (HH) signaling. In mice, pharmacological inhibition of the HH pathway causes taste bud loss within a few weeks. Previously, we demonstrated that sonic hedgehog (SHH) overexpression in lingual progenitors induces ectopic taste buds with locally increased SOX2 expression, suggesting that taste bud differentiation depends on SOX2 downstream of HH. To test this, we inhibited HH signaling in mice and observed a rapid decline in Sox2 and SOX2-GFP expression in taste epithelium. Upon conditional deletion of Sox2, differentiation of both taste and non-taste epithelial cells was blocked, and progenitor cell number increased. In contrast to basally restricted proliferation in controls, dividing cells were overabundant and spread to suprabasal epithelial layers in mutants. SOX2 loss in progenitors also led non-cell-autonomously to taste cell apoptosis, dramatically shortening taste cell lifespans. Finally, in tongues with conditional Sox2 deletion and SHH overexpression, ectopic and endogenous taste buds were not detectable; instead, progenitor hyperproliferation expanded throughout the lingual epithelium. In summary, we show that SOX2 functions downstream of HH signaling to regulate lingual epithelium homeostasis.

Abstract LB-046: Castration-resistant Bmi1+Sox2+ cells drive recurrence in prostate cancer

Abstract Introduction: Recurrence is associated with mortality in prostate cancer, but the cellular origins and molecular mechanisms that drive this process have not been well-defined. An emerging model of resistance to androgen deprivation therapy (ADT) in prostate cancer, particularly to the more potent newer drugs, involves lineage plasticity or transdifferentiation. Epigenetic regulators and stem cell reprogramming factors including Sox2 and Ezh2 appear to play important roles in this process. However, there has been a paucity of studies that attempt to specifically follow the fate of malignant prostate cells in regressed tumors following castration in order to understand the cellular processes associated with the emergence of castration-resistant prostate cancer (CRPC). We recently identified a population of luminal progenitors termed castration-resistant Bmi1-expressing cells (CARBs) in the mouse prostate that serve as a prostate cancer cell of origin. Here, we hypothesized that analogous castration-resistant Bmi1-expressing tumor cells (tumor CARBs) exist in prostate cancer and could seed recurrence after ADT. Methods: We adopted lineage retracing strategies using an inducible Bmi1-CreER driver and a multicolor reporter R26R-Confetti allele, which enables lineage-marking and kinetically re-tracing of the emerging recurrent tumor clones within castrated tumors over times in vivo. A tissue recombination strategy was used to rescue transgenic Bmi1-CreER; Ptenf/f mice (BC-Pten) mouse prostates by regeneration as grafts in SCID mice. The ability of tumor CARBs to seed recurrence was determined by lineage retracing methodology of castrated mice after establishing tumor by tamoxifen treatment, which was coupled with immunohistochemistry and Western blotting. We also used a small molecule Bmi1 inhibitor, PTC-209, to directly test the role of Bmi1 in recurrence. Results: Deletion of Pten in Bmi1+ luminal prostate progenitors generates a luminal prostate cancer that regresses upon castration, followed by recurrence over time. Notably, castration induced a transient luminal-to-basal phenotypic switch in regressed tumors with recurrent tumors reverting to a luminal phenotype. Analysis of regressed tumors post-castration showed cellular heterogeneity, with a population of apoptosis-resistant, proliferative, Bmi1-expressing tumor cells that also upregulate expression of the stem cell reprogramming factor Sox2. Expression of Sox2 was maintained in recurrent tumors despite loss of basal cell transdifferentiation. Lineage re-tracing with the R26R-Confetti allele established that Bmi1+ tumor cells in regressed tumors drive recurrence. Furthermore, treatment with the small molecule Bmi1 inhibitor PTC-209 eliminated Bmi1+Sox2+ cells and significantly decreased recurrence. Conclusion: These results shed light on the cellular origins of recurrent prostate cancer and the roles of the epigenetic/stem cell regulators Bmi1 and Sox2 in therapeutic resistance to androgen deprivation. Citation Format: Young A. Yoo, Rajita Vatapalli, Barbara Lysy, Hanlin Mok, Mohamed M. Desouki, Sarki A. Abdulkadir. Castration-resistant Bmi1+Sox2+ cells drive recurrence in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-046.

Heterogeneous Expression of Embryonal Development Master Regulator SOX9 in Patients with Pancreatic Cancer.

The expression levels of the SOX9 gene in fetal, postnatal, and neoplastic pancreatic tissues were compared. In the fetal pancreatic samples, the mean relative level of the SOX9 gene expression was 8 times greater than the normal level. The tumor samples were divided into three groups depending on the SOX9 expression level. The first group showed a 6.5-fold increased expression level of SOX9 with respect to the normal one. The second and normal groups had approximately equal levels expression. The third group showed a 25-fold decreased expression level of SOX9. The discrepancy in the SOX9 expression, associated with the predominance of different functions of this master gene, depends on the poorly predictable individual factors and indicates that SOX9 should be excluded from the potential diagnostic biomarkers of pancreatic cancer.

Sox9 regulation during sex determination

Sex Determination Sex determination is regulated by the Sox9 gene. During testis differentiation, this gene is directly targeted by the product of the Y chromosome–encoded gene Sry . The regulatory region of Sox9 is complex, which is typical of genes with multiple roles in development. Gonen et al. find that a single far-upstream 557–base pair element is critical for up-regulating Sox9 . Without it, XY mice develop as females instead of males. The 557–base pair enhancer is conserved, likely to be relevant to human disorders of sex differentiation, and probably essential because it acts early in a time-critical process, and any failure allows ovary-specific factors to dominate. Science , this issue p. [1469][1] [1]: /lookup/doi/10.1126/science.aas9408

Ligustrazine protects chondrocyte against IL-1β induced injury by regulation of SOX9/NF-κB signaling pathway.

Ligustrazine is extracted from rhizoma ligustici wallichii, is known for its vasodilatory properties in the traditional Chinese herbal medicine. The study aimed to determine the effect and the underlying mechanism of ligustrazine on interleukin-1β (IL-1β)-induced injury in osteoarthritis (OA). Human articular cartilages and joint effusion were obtained from patients with OA, and the chondrocytes were isolated and treated with IL-1β. The different inflammatory cytokines were analyzed by ELISA. Cell viability, apoptosis, and apoptosis-related factors were examined by MTT, flow cytometry, and Western blot. Then, the expressions of COL2A1 and ACAN, and the concentrations of sGAG and MMP-13 were measured. The level of SOD and MDA and ROS production were then analyzed. Furthermore, the protein levels of SOX9 and NF-κB pathway were detected by Western blot. Ligustrazine significantly suppressed inflammatory reaction in joint effusion of OA patients. Moreover, ligustrazine attenuated IL-1β-induced chondrocytes injury and matrx degradation in chondrocytes. Ligustrazine promoted oxidative stress response by increasing SOD level, decreasing MDA level, and inhibiting ROS production in IL-1β-induced chondrocytes. Besides, ligustrazine increased SOX9 expression, and SOX9 silencing reversed the effect of ligustrazine on matrx degradation in IL-1β-injured chondrocytes. Furthermore, ligustrazine blocked NF-κB pathway in IL-1β-induced chondrocytes, and PTDC (NF-κB inhibitor) enhanced the effect of ligustrazine on viability, apoptosis, SOX9 expression, and ROS production in IL-1β-induced chondrocytes. These results indicated that ligustrazine protected chondrocytes against IL-1β-induced injury possibly by regulation of SOX9 and inactivation of NF-κB signaling pathway. It could act as a therapeutic agent for the treatment of OA.

Endothelial Cells Modulate Differentiation Potential and Mobility of Mesenchymal Stromal Cells.

We studied the effect of endothelial cells on in vitro migration and differentiation potential of multipotent mesenchymal stromal cells. Down-regulation of stemness genes OCT4, SOX2, and chondrogenic differentiation regulator SOX9 gene and upregulation of osteogenesis master-gene RUNX2 in mesenchymal stromal cells were observed in the presence of intact and TNFα-activated endothelial cells, which indicated an increase in commitment of mesenchymal stromal cells.The medium conditioned by endothelial cells stimulated migration activity of mesenchymal stromal cells; migration rate increased significantly in conditioned medium from activated cells in comparison with medium from non-activated cells. It was concluded that the interaction with endothelial cells modulated functional activity of mesenchymal stromal cells; moreover, activated endothelial cells produced more pronounced effects on differentiation potential and migration activity of mesenchymal stromal cells both in direct contact and through paracrine regulation.

Expression of the Sox9, Foxl2, Vasa, and TRPV4 genes in the ovaries and testes of the Morelet's crocodile, Crocodylus moreletii.

The Sox9 gene is important for determining sex in vertebrates, as well as for maintaining testis morphology and fertility during adult life. In the same way, Vasa is an important gene for the maintenance of the germinal lineage and has been highly conserved throughout evolution, as it is expressed in germ cells of both vertebrates and invertebrates. In the particular case of crocodiles, the expression of Sox9 during gonadal morphogenesis and in the testes of 3-month-old Alligator mississippiensis has been studied. However, it is interesting to carry out studies on other species of crocodiles in relation to their particular mechanism for sex determination influenced by temperature. In this work, we investigated the expression of the Sox9, Vasa, Foxl2, and TRPV4 genes in the ovaries and testes of 5-year-old juvenile crocodiles from Crocodylus moreletii. As expected, Sox9 expression was found in males, but surprisingly, it was also found in females. For the first time, the expression of Vasa was reported in spermatogonia, oogonia, and oocytes of 5-year-old crocodiles. Foxl2 is important for the development and maintenance of the ovary during adult life in vertebrates; moreover, Foxl2 protein and transcripts are both highly expressed in the ovaries compared to the testes. A possible upstream regulator of the Sox9 gene in reptiles has not yet been discovered; as such, the expression of the TRPV4 ion channel was evaluated. The TRPV4 ion channel was expressed in the cytoplasm of Sertoli and follicular cells and was therefore proposed as a possible regulator of SOX9.

Low SOX2 expression marks a distinct subset of adenoid cystic carcinoma of the head and neck and is associated with an advanced tumor stage.

IntroductionThe transcription factor SOX2 has been identified as a lineage survival oncogene in squamous cell carcinoma and copy number gain is a common event in several human malignancies including head and neck cancer. However, the regulation and function of SOX2 during carcinogenesis as well as its prognostic value appears to be highly context dependent. As an example, high SOX2 expression in lung squamous cell carcinoma (SCC) is related to a favorable prognosis, while it is associated with poor outcome in lung adenocarcinoma. More recently, higher SOX2 levels and improved survival was also reported for head and neck SCC (HNSCC), and silencing of SOX2 expression in HNSCC cell lines revealed a mesenchymal-like phenotype with prominent vimentin expression. So far, SOX2 expression and its clinical relevance for other head and neck cancers, such as adenoid cystic carcinoma (HNACC) have not been sufficiently investigated.Material and methodsSOX2, vimentin and E-cadherin expression was assessed by immunohistochemical staining on serial sections from formalin fixed and paraffin embedded tissue samples of a patient cohort (n = 45) with primary ACC and correlated with patient and tumor characteristics as well as survival.ResultsHigh SOX2 expression was found in 14 (31%) primary tumor specimens and was significantly correlated with a N0 lymph node status (p = 0.04), while low SOX2 expression was correlated with a solid growth pattern (p = 0.031). Of the 45 patients, 27 tumor samples resembled an EMT-like phenotype, as assessed by high vimentin and low E-cadherin levels. However, in HNACC SOX2 levels were neither correlated with vimentin nor with E-cadherin expression, further supporting a context dependent regulation and function of SOX2 in distinct tumor entities.ConclusionThe absence of SOX2 was predominantly found in solid HNACC, which are characterized by a more aggressive phenotype in ACC. However, the underlying molecular mechanisms of SOX2 regulation and function in distinct HNACC subgroups remain to be fully elucidated.

Roles of Ihh signaling in chondroprogenitor function in postnatal condylar cartilage

Condylar articular cartilage in mouse temporomandibular joint develops from progenitor cells near the articulating surface that proliferate, undergo chondrogenesis and mature into hypertrophic chondrocytes. However, it remains unclear how these processes are regulated, particularly postnatally. Here we focused on the apical polymorphic layer rich in progenitors and asked whether the phenotype and fate of the cells require signaling by Indian hedgehog (Ihh) previously studied in developing long bones. In condyles in newborn mice, the apical polymorphic/progenitor cell layer was ~10 cell layer-thick and expressed the articular matrix marker Tenascin-C (Tn-C), and the underlying thick cell layer expressed Tn-C as well as the chondrogenic master regulator Sox9. By 1 month, condylar cartilage had gained its full width, but became thinner along its main longitudinal axis and displayed hypertrophic chondrocytes. By 3 months, articular cartilage consisted of a 2–3 cell layer-thick zone of superficial cells and chondroprogenitors expressing both Tn-C and Sox9 and a bottom zone of chondrocytes displaying vertical matrix septa. EdU cell tracing in juvenile mice revealed that conversion of chondroprogenitors into chondrocytes and hypertrophic chondrocytes required about 48 and 72 h, respectively. Notably, EdU injection in 3 month-old mice labeled both progenitors and maturing chondrocytes by 96 h. Conditional ablation of Ihh in juvenile/early adult mice compromised chondroprogenitor organization and function and led to reduced chondroprogenitor and chondrocyte proliferation. The phenotype of mutant condyles worsened over time as indicated by apoptotic chondrocyte incidence, ectopic chondrocyte hypertrophy, chondrocyte column derangement and subchondral bone deterioration. In micromass cultures of condylar apical cells, hedgehog (Hh) treatment stimulated chondrogenesis and alkaline phosphatase (APase) activity, while treatment with HhAntag inhibited both. Our findings indicate that the chondroprogenitor layer is continuously engaged in condylar growth postnatally and its organization and functioning depend on hedgehog signaling.

Allele-specific repression of Sox2 through the long non-coding RNA Sox2ot

The transcription factor Sox2 controls the fate of pluripotent stem cells and neural stem cells. This gatekeeper function requires well-regulated Sox2 levels. We postulated that Sox2 regulation is partially controlled by the Sox2 overlapping long non-coding RNA (lncRNA) gene Sox2ot. Here we show that the RNA levels of Sox2ot and Sox2 are inversely correlated during neural differentiation of mouse embryonic stem cells (ESCs). Through allele-specific enhanced transcription of Sox2ot in mouse Sox2eGFP knockin ESCs we demonstrate that increased Sox2ot transcriptional activity reduces Sox2 RNA levels in an allele-specific manner. Enhanced Sox2ot transcription, yielding lower Sox2 RNA levels, correlates with a decreased chromatin interaction of the upstream regulatory sequence of Sox2 and the ESC-specific Sox2 super enhancer. Our study indicates that, in addition to previously reported in trans mechanisms, Sox2ot can regulate Sox2 by an allele-specific mechanism, in particular during development.

Dr. Jekyl-Mr. Hyde Role of Sox Family–From Neurogenesis to Cancer: A Review.

After the historic discovery of IPSCs by Shinya Yamanaka, Sox2 became a highly important factor for its crucial role in reprogramming of somatic cells. The transcriptional control of various phases of nerve cell development, which include stem-cell maintenance, glial specification and lineage-specific terminal differentiation, are not well understood. This is where Sox proteins come into play. Recently, SOX2 expression has been corroborated in several tumor types including ovarian carcinoma, which suggests an involvement of SOX2 in regulation of cancer stem cells (CSC). SOX antibodies have been categorized as specific serological markers for Small cell lung cancer. However Sox2 reduction leads to neurodegeneration. Thus understanding the expression of this protein is very important. Here is an overview of the present knowledge we possess about the functional mechanisms of SOX family, with an effort to understand the role in both development and disease.

Long non-coding RNA MALAT-1 contributes to maintenance of stem cell-like phenotypes in breast cancer cells.

Due to the accumulating evidence that has demonstrated the vital role of cancer stem cells (CSCs) in tumor initiation, progression and metastasis, the mechanisms that maintain the stemness of CSCs have attracted increasing attention. Metastasis-associated lung adenocarcinoma transcript-1 (MALAT-1), a long non-coding RNA, which has been revealed to be associated with the malignant behavior of tumors, performs a critical role in maintaining the stemness in several CSCs. In the present study, it was hypothesized that MALAT-1 promotes stem cell-like phenotypes in breast cancer cells. The present data demonstrated that the expression of MALAT-1 was higher in the CSC subpopulation compared with that in the overall MCF7 cell group and that the knockdown of MALAT-1 decreased the proportion of CSCs. The self-renewal assay also demonstrated that knockdown of MALAT-1 decreased the sphere formation rate in vitro. In addition, MALAT-1 is also able to regulate the proliferation, colony formation, migration and invasion of CSCs in vitro. The underlying mechanisms may involve the regulation of self-renewal-associated factors, including sex-determining region Y-box 2 (Sox-2). Taken together, the present study demonstrated that MALAT-1 affects the stem cell-like phenotypes in breast cancer cells through regulation of Sox-2.

Nasal and otic placode specific regulation of Sox2 involves both activation by Sox-Sall4 synergism and multiple repression mechanisms

Transcription factor gene Sox2 is expressed throughout sensory development, but the enhancers that regulate the gene vary depending on the developmental stages and tissues. To gain new insights into the gene regulatory network in sensory placode specification, regulation of the nasal-otic bispecific NOP1 enhancer of Sox2 was investigated in chicken embryos. Deletion and mutational analyses using electroporation showed that transcriptional repression mechanisms in combination with activation mechanisms determine placodal specificity. Activation of the NOP1 enhancer involves synergistic action by Sall4 and SoxB1/SoxE factors that bind to the adjacent sites. Deletion of repressive elements resulted in widening of the tissue area for enhancer activity to a region where the expression of Sall4 and SoxB1/E overlaps, e.g., the CNS and neural crest. Among multiple repressive elements that contribute to the placodal confinement of the NOP1 enhancer activity, CACCT/CACCTG motifs bound by Zeb/Snail family repressors play important roles. Overexpression of δEF1 (Zeb1) or Snail2 (Slug) strongly inhibited NOP1 activity. These data indicate that both activation by Sall4-Sox synergism and multiple repression mechanisms involving Zeb/Snail factors are essential for Sox2 regulation to be confined to the nasal and otic placodes.

TGF-\u03b2 signalling and PEG10 are mutually exclusive and inhibitory in chondrosarcoma cells

Histological distinction between enchondroma and chondrosarcoma is difficult because of a lack of definitive biomarkers. Here, we found highly active transforming growth factor-β (TGF-β) and bone morphogenetic protein (BMP) signalling in human chondrosarcomas compared with enchondromas by immunohistochemistry of phosphorylated SMAD3 and SMAD1/5. In contrast, the chondrogenic master regulator SOX9 was dramatically down-regulated in grade 1 chondrosarcoma. Paternally expressed gene 10 (PEG10) was identified by microarray analysis as a gene overexpressed in chondrosarcoma SW1353 and Hs 819.T cells compared with C28/I2 normal chondrocytes, while TGF-β1 treatment, mimicking higher grade tumour conditions, suppressed PEG10 expression. Enchondroma samples exhibited stronger expression of PEG10 compared with chondrosarcomas, suggesting a negative association of PEG10 with malignant cartilage tumours. In chondrosarcoma cell lines, application of the TGF-β signalling inhibitor, SB431542, increased the protein level of PEG10. Reporter assays revealed that PEG10 repressed TGF-β and BMP signalling, which are both SMAD pathways, whereas PEG10 knockdown increased the level of phosphorylated SMAD3 and SMAD1/5/9. Our results indicate that mutually exclusive expression of PEG10 and phosphorylated SMADs in combination with differentially expressed SOX9 is an index to distinguish between enchondroma and chondrosarcoma, while PEG10 and TGF-β signalling are mutually inhibitory in chondrosarcoma cells.

SOX9 Regulates Cancer Stem-Like Properties and Metastatic Potential of Single-Walled Carbon Nanotube-Exposed Cells

Engineered nanomaterials hold great promise for the future development of innovative products but their adverse health effects are a major concern. Recent studies have indicated that certain nanomaterials, including carbon nanotubes (CNTs), may be carcinogenic. However, the underlying mechanisms behind their potential malignant properties remain unclear. In this study, we linked SOX9, a stem cell associated transcription factor, to the neoplastic-like properties of human lung epithelial cells chronically exposed to a low-dose of single-walled carbon nanotubes (SWCNTs). We found that SOX9 is upregulated in SWCNT-exposed cells, which is consistent with their abilities to induce tumor formation and metastasis in vivo. We therefore hypothesized that SOX9 overexpression may be responsible for the neoplastic-like phenotype observed in our model. Indeed, SOX9 knockdown inhibited anchorage-independent cell growth in vitro and lung colonization in vivo in a mouse xenograft model. SOX9 depletion also suppressed the formation of cancer stem-like cells (CSCs), as determined by tumor sphere formation and aldehyde dehydrogenase (ALDH) activity (Aldefluor) assays. Furthermore, SOX9 knockdown suppressed tumor metastasis and the expression of the stem cell marker ALDH1A1. Taken together, our findings provide a mechanistic insight into SWCNT-induced carcinogenesis and the role of SOX9 in CSC regulation and metastasis.

3'-Sialyllactose protects against osteoarthritic development by facilitating cartilage homeostasis.

3′‐Sialyllactose has specific physiological functions in a variety of tissues; however, its effects on osteoarthritic development remain unknown. Here, we demonstrated the function of 3′‐sialyllactose on osteoarthritic cartilage destruction. In vitro and ex vivo, biochemical and histological analysis demonstrated that 3′‐sialyllactose was sufficient to restore the synthesis of Col2a1 and accumulation of sulphated proteoglycan, a critical factor for cartilage regeneration in osteoarthritic development, and blocked the expression of Mmp3, Mmp13 and Cox2 induced by IL‐1β, IL‐6, IL‐17 and TNF‐α, which mediates cartilage degradation. Further, reporter gene assays revealed that the activity of Sox9 as a transcription factor for Col2a1 expression was accelerated by 3′‐sialyllactose, whereas the direct binding of NF‐κB to the Mmp3, Mmp13 and Cox2 promoters was reduced by 3′‐sialyllactose in IL‐1β‐treated chondrocytes. Additionally, IL‐1β induction of Erk phosphorylation and IκB degradation, representing a critical signal pathway for osteoarthritic development, was totally blocked by 3′‐sialyllactose in a dose‐dependent manner. In vivo, 3′‐sialyllactose protected against osteoarthritic cartilage destruction in an osteoarthritis mouse model induced by destabilization of the medial meniscus, as demonstrated by histopathological analysis. Our results strongly suggest that 3′‐sialyllactose may ameliorate osteoarthritic cartilage destruction by cartilage regeneration via promoting Col2a1 production and may inhibit cartilage degradation and inflammation by suppressing Mmp3, Mmp13 and Cox2 expression. The effects of 3′‐sialyllactose could be attributed in part to its regulation of Sox9 or NF‐κB and inhibition of Erk phosphorylation and IκB degradation. Taken together, these effects indicate that 3′‐sialyllactose merits consideration as a natural therapeutic agent for protecting against osteoarthritis.

Abstract 1913: SOX9 regulates cancer stem-like cells in non-small cell lung cancer

Abstract Lung cancer is the leading cause of cancer death worldwide in both men and women, every year killing more people than breast, prostate and colon cancers combined. Drug/radiation resistance and tumor relapse contribute to low patient survival, which has largely been attributed to the acquisition of stem-like cells (CSCs), or tumor initiating cells. Moreover, conventional therapies are not effective against CSCs. This signifies the need to identify mechanisms of CSC regulation which could lead to the discovery of CSC-specific drug targets and the development of more effective drug therapies. An embryonic transcription factor SOX9 has been implicated in CSC regulation in a number of cancer types, but little is known about its role in non-small cell lung cancer (NSCLC). We demonstrated that high SOX9 expression correlates with poor survival in lung cancer patients by analyzing The Cancer Genome Atlas (TCGA) data. We hypothesized that SOX9 plays a key role in tumor progression and chemoresistance by upregulating CSCs in NSCLC. To test this hypothesis, SOX9 expression was stably or transiently knocked down in NSCLC cells, and their effects on CSC formation and biomarkers, and on drug resistance were investigated. Our results showed that SOX9 knockdown decreased the number of tumor spheres in NSCLC cell lines. Furthermore, SOX9 knockdown downregulated the expression and activity of stem cell marker ALDH1A1 as determined by Western blot and flow cytometric assays. Consistent with this finding, overexpression of SOX9 in non-cancer lung epithelial Beas-2B cells elevated tumor sphere formation, supporting the role of SOX9 in CSC regulation. Analysis of the soft agar colony formation assay further showed that SOX9 knockdown inhibited anchorage-independent growth in NSCLC cells. More importantly, SOX9 knockdown resulted in an increased sensitivity of the cells to a chemotherapeutic drug cisplatin, whereas SOX9 overexpression decreased it. Together, our results indicate an important role of SOX9 in the regulation of CSCs in NSCLC and suggest its potential utility as a drug target for chemoresistant lung cancer. Citation Format: Maria Voronkova, Sudjit Luanpitpong, Heimo Riedel, Yon Rojanasakul. SOX9 regulates cancer stem-like cells in non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1913. doi:10.1158/1538-7445.AM2017-1913

SOX2 regulates acinar cell development in the salivary gland.

Acinar cells play an essential role in the secretory function of exocrine organs. Despite this requirement, how acinar cells are generated during organogenesis is unclear. Using the acini-ductal network of the developing human and murine salivary gland, we demonstrate an unexpected role for SOX2 and parasympathetic nerves in generating the acinar lineage that has broad implications for epithelial morphogenesis. Despite SOX2 being expressed by progenitors that give rise to both acinar and duct cells, genetic ablation of SOX2 results in a failure to establish acini but not ducts. Furthermore, we show that SOX2 targets acinar-specific genes and is essential for the survival of acinar but not ductal cells. Finally, we illustrate an unexpected and novel role for peripheral nerves in the creation of acini throughout development via regulation of SOX2. Thus, SOX2 is a master regulator of the acinar cell lineage essential to the establishment of a functional organ.