A CD44/Brg1 nuclear complex confers mesenchymal progenitor cells with enhanced fibrogenicity in idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disease. We previously identified fibrogenic mesenchymal progenitor cells (MPCs) in the lungs of patients with IPF who serve as drivers of progressive fibrosis. Recent single-cell RNA sequencing work revealed that IPF MPCs with the highest transcriptomic network entropy differ the most from control MPCs and that increased CD44 was a marker of these IPF MPCs. We hypothesize that IPF MPCs with high CD44 (CD44hi) expression will display enhanced fibrogenicity. We demonstrate that CD44-expressing MPCs are present at the periphery of the IPF fibroblastic focus, placing them in regions of active fibrogenesis. In a humanized mouse xenograft model, CD44hi IPF MPCs are more fibrogenic than CD44lo IPF MPCs, and knockdown of CD44 diminishes their fibrogenicity. CD44hi IPF MPCs display increased expression of pluripotency markers and enhanced self-renewal compared with CD44lo IPF MPCs, properties potentiated by IL-8. The mechanism involves the accumulation of CD44 within the nucleus, where it associates with the chromatin modulator protein Brahma-related gene 1 (Brg1) and the zinc finger E-box binding homeobox 1 (Zeb1) transcription factor. This CD44/Brg1/Zeb1 nuclear protein complex targets the Sox2 gene, promoting its upregulation and self-renewal. Our data implicate CD44 interaction with the epigenetic modulator protein Brg1 in conveying IPF MPCs with cell-autonomous fibrogenicity.

Pancreatic cancer drug-sensitivity predicted by synergy of p53-Activator Wnt Inhibitor-2 (PAWI-2) and protein biomarker expression.

Today, pancreatic cancer (PC) is a major health problem in the United States. It remains a challenge to develop efficacious clinically useful PC therapies. New avenues, based on translational approaches and innovative validated biomarkers could be a preclinical option to evaluate PC drug candidates or drug combinations before clinical trials. Herein, we describe evaluation of combination therapies by incorporating a novel pathway modulator, p53-Activator Wnt Inhibitor-2 (PAWI-2) with other FDA-approved cancer drugs that have been used in PC clinical trials. PAWI-2 is a potent inhibitor of drug-resistant PC cells that has been shown to selectively ameliorate human pancreatic cancer stem cells (i.e., hPCSCs, FGß3 cells). In the present study, we showed PAWI-2 produced therapeutic synergism with certain types of anti-cancer drugs. These drugs themselves oftentimes do not ameliorate PC cells (especially PCSCs) due to high levels of drug-resistance. PAWI-2 has the ability to rescue the potency of drugs (i.e., erlotinib, trametinib) and inhibit PC cell growth. Key molecular regulators of PAWI-2 could be used to predict synergistic/antagonistic effects between PAWI-2 and other anti-cancer drugs. Anti-cancer results showed potency could be quite accurately correlated to phosphorylation of optineurin (OPTN) in PC cells. Synergism/antagonism was also associated with inhibition of PCSC marker SOX2 that was observed in FGß3 cells. Synergism broadens the potential use of PAWI-2 as an adjunct chemotherapy in patients with PC that have developed resistance to first-line targeted therapies or chemotherapies.

Effects of Apatinib on the "Stemness" of Non-Small-Cell Lung Cancer Cells In Vivo and Its Related Mechanisms.

Objective: To investigate the effects of Apatinib on the "stemness" of lung cancer cells in vivo and to explore its related mechanisms. Methods: A xenograft model of lung cancer cells A549 was established in nude mice and randomized into a control group (n = 4) and an Apatinib group (n = 4). Tumor tissues were harvested after 2 weeks, and mRNA was extracted to detect changes in stemness-related genes (CD133, EPCAM, CD13, CD90, ALDH1, CD44, CD45, SOX2, NANOG, and OCT4) and Wnt/ß-catenin, Hedgehog, and Hippo signal pathways. Results: Compared with the control group, the volume and weight of nude mice treated with Apatinib were different and had statistical significance. Apatinib inhibited the expressions of ABCG2, CD24, ICAM-1, OCT4, and SOX2 and upregulated the expressions of CD44, CD13, and FOXD3. Apatinib treatment also inhibited the Wnt/ß-catenin, Hedgehog, and Hippo signaling pathways. Conclusion: Apatinib suppressed the growth of non-small-cell lung cancer cells by repressing the stemness of lung cancer through the inhibition of the Hedgehog, Hippo, and Wnt signaling pathways.

Up-regulated lnc-lung cancer associated transcript 1 enhances cell migration and invasion in breast cancer progression.

Breast cancer remains a leading cause of tumor-related deaths in the world. The pathogenesis contributing to breast cancer progression has not been fully understood. Increasing evidence suggests that long noncoding RNA (lncRNA) is implicated in various kinds of malignant cancers, including breast cancer. In the study, we attempted to explore the expression and effects of lnc-lung cancer associated transcript 1 (LUCAT1) on breast cancer development. Our results indicated that the expression of lnc-LUCAT1 was highly up-regulated in breast cancer tissues and cell lines. Over-expression of lnc-LUCAT1 enhanced cell proliferation, migration and invasion in breast cancer cell lines. Moreover, lnc-LUCAT1 was found to be a target of miR-7-5p. There was a negative correlation between lnc-LUCAT1 and miR-7-5p. The reduction of miR-7-5p was required in the augmentation of breast cancer development induced by lnc-LUCAT1 over-expression. In addition, SOX2 acted as a target of miR-7-5p. SOX2 was an oncogene in breast cancer through promoting cell proliferation, migration and invasion. The in vivo study confirmed the role of lnc-LUCAT1 in promoting tumor growth, accompanied with down-regulated SOX2 expression, whereas up-regulated miR-7-5p. Collectively, the lnc-LUCAT1/miR-7-5p-SOX2 regulatory pathway might provide a new and effective therapeutic strategy to prevent breast cancer development.

Targeting Mcl-1 inhibits survival and self-renewal of hepatocellular cancer stem-like cells.

Myeloid cell leukemia-1 (Mcl-1) is highly expressed in tumor tissues and cells of hepatocellular carcinoma (HCC), yet the role of Mcl-1 in cancer stem-like cells (CSLCs) remains largely unclear. Herein, we showed that knockdown of Mcl-1 significantly inhibited HCC cells to form spheres under ultra-low attachment condition in serum-free medium, and also attenuated clone formation. Inhibition of Mcl-1 by specific inhibitors S63845 or A-1210477 hindered secondary sphere formation, triggered apoptosis signaling and reduced the level of stem cell transcription factor Nanog, Sox2 and KLF4 in HCC spheroids cells. This study suggests that Mcl-1 is an essential factor for the survival and self-renewal of HCC CSLCs.

Toxic responses of Sox2 gene in the regeneration of the earthworm Eisenia foetida exposed to Retnoic acid.

Exogenous retinoic acid delays and disturbs the regeneration of Eisenia foetida. The stem cell pluripotency factor, Sox2, can play a crucial role in cell reprogramming and dedifferentiation. In this study, we compared the regeneration of Eisenia foetida in different segments after amputation and the effects of retinoic acid on the regeneration of different segments. The results showed that the regeneration speed of the head and tail was slightly faster than the middle part, and retinoic acid disrupted and delayed the regeneration of the earthworm. The qRT-PCR and Western blot analysis showed that the expression of the Sox2 gene and Sox2 protein was highest on the seventh day in different segments (p<0.05). After treatment with retinoic acid, the expression level of the Sox2 gene and Sox2 protein was significantly reduced (p<0.05). The results indicated that the regeneration of earthworms and the formation of blastema are related to the expression of the Sox2 gene and protein. Retinoic acid delays and interferes with the regeneration of the earthworm by affecting the expression levels of the Sox2 gene and protein.

Carnosic acid induces proteasomal degradation of Cyclin B1, RB and SOX2 along with cell growth arrest and apoptosis in GBM cells.

BACKGROUND: Carnosic acid (CA) is a diterpenoid found in Rosmarinus officinalis L. and Salvia officinalis L. as well as in many other Lamiaceae. This compound is reported to have antioxidant and antimicrobial properties. In addition, a number of reports showed that CA has a cytotoxic activity toward several cancer cell lines. PURPOSE: The aim of this study was to establish whether CA has any specific antiproliferative effect toward human glioblastoma (GBM) cells and to analyze the molecular mechanisms involved. METHODS: We evaluated cell survival by MTT assay, apoptosis and DNA content by flow cytometry, protein expression and phosphorylation by immunoblot analyses. RESULTS: Our results showed that CA inhibited cell survival on both normal astrocytes and GBM cells. In GBM cells, in particular, CA caused an early G2 block, a reduction in the percentage of cells expressing Ki67, an enhanced expression of p21(WAF) and induced apoptosis. Furthermore, we showed that CA promoted proteasomal degradation of several substrate proteins, including Cyclin B1, retinoblastoma (RB), SOX2, and glial fibrillary acid protein (GFAP), whereas MYC levels were not modified. In addition, CA dramatically reduced the activity of CDKs. CONCLUSION: In conclusion, our findings strongly suggest that CA promotes a profound deregulation of cell cycle control and reduces the survival of GBM cells via proteasome-mediated degradation of Cyclin B1, RB and SOX2.

SOX1 functions as a tumor suppressor by antagonizing the WNT/ß-catenin signaling pathway in hepatocellular carcinoma.

UNLABELLED: Oncogenic activation of the Wnt/ß-catenin signaling pathway is common in hepatocellular carcinoma (HCC). Our recent studies have demonstrated that SRY (sex determining region Y)-box 1 (SOX1) and secreted frizzled-related proteins are concomitantly promoter-hypermethylated, and this might lead to abnormal activation of the Wnt signaling pathway in HCC. SOX1 encodes a transcription factor involved in the regulation of embryonic development and cell fate determination. However, the expression and functional role of SOX1 in HCC remains unclear. In this study, we confirmed via quantitative methylation-specific polymerase chain reaction that SOX1 was frequently downregulated through promoter hypermethylation in HCC cells and tissues. Overexpression of SOX1 by a constitutive or inducible approach could suppress cell proliferation, colony formation, and invasion ability in HCC cell lines, as well as tumor growth in nonobese diabetic/severe combined immunodeficiency mice. Conversely, knockdown of SOX1 by withdrawal of doxycycline could partially restore cell proliferation and colony formation in HCC cells. We used a T cell factor (TCF)-responsive luciferase reporter assay and western blot analysis to prove that SOX1 could regulate TCF-responsive transcriptional activity and inhibit the expression of Wnt downstream genes. Furthermore, we used glutathione S-transferase pull-down, co-immunoprecipitation, and confocal microscopy to demonstrate that SOX1 could interact with ß-catenin but not with the ß-catenin/TCF complex. Moreover, restoration of the expression of SOX1 induces significant cellular senescence in Hep3B cells. CONCLUSION: Our data show that a developmental gene, SOX1, may function as a tumor suppressor by interfering with Wnt/ß-catenin signaling in the development of HCC.

BMP4 induces primitive endoderm but not trophectoderm in monkey embryonic stem cells.

Monkey embryonic stem (ES) cells share similar characteristics to human ES cells and provide a primate model of allotransplantation, which allows to validate efficacy and safety of cell transplantation therapy in regenerative medicine. Bone morphogenetic protein 4 (BMP4) is known to promote trophoblast differentiation in human ES cells in contrast to mouse ES cells where BMP4 synergistically maintains self-renewal with leukemia inhibitory factor (LIF), which represents a significant difference in signal transduction of self-renewal and differentiation between murine and human ES cells. As the similarity of the differentiation mechanism between monkey and human ES cells is of critical importance for their use as a primate model system, we investigated whether BMP4 induces trophoblast differentiation in monkey ES cells. Interestingly, BMP4 did not induce trophoblast differentiation, but instead induced primitive endoderm differentiation. Prominent downregulation of Sox2, which plays a pivotal role not only in pluripotency but also placenta development, was observed in cells treated with BMP4. In addition, upregulation of Hand1, Cdx2, and chorionic gonadotropin beta (CG-beta), which are markers of trophoblast, was not observed. In contrast, BMP4 induced significant upregulation of Gata6, Gata4, and LamininB1, suggesting differentiation into the primitive endoderm, visceral endoderm, and parietal endoderm, respectively. The threshold of BMP4 activity was estimated as about 10 ng/mL. These findings suggest that BMP4 induced differentiation into the primitive endoderm lineage but not into trophoblast in monkey ES cells.