Metastatic Ovarian Serous Adenocarcinoma Clinically Presenting as Inflammatory Breast Cancer

Metastatic disease to the breast is a rare event, accounting for 0.5-2% of all breast cancers. Outside of metastases from the contralateral breast, malignant ovarian epithelial tumors are the most common origin of these metastases. Here, we present a very rare case of a high-grade ovarian serous adenocarcinoma presenting clinically as inflammatory breast cancer in a 70-year-old woman.

Bacterial antibiotic resistance among cancer inpatients in China: 2016-20

BACKGROUND

The incidence of infections among cancer patients is as high as 23.2-33.2% in China. However, the lack of information and data on the number of antibiotics used by cancer patients is an obstacle to implementing antibiotic management plans.

AIM

This study aimed to investigate bacterial infections and antibiotic resistance in Chinese cancer patients to provide a reference for the rational use of antibiotics.

DESIGN

This was a 5-year retrospective study on the antibiotic resistance of cancer patients.

METHODS

In this 5-year surveillance study, we collected bacterial and antibiotic resistance data from 20 provincial cancer diagnosis and treatment centers and three specialized cancer hospitals in China. We analyzed the resistance of common bacteria to antibiotics, compared to common clinical drug-resistant bacteria, evaluated the evolution of critical drug-resistant bacteria and conducted data analysis.

FINDINGS

Between 2016 and 2020, 216 219 bacterial strains were clinically isolated. The resistance trend of Escherichia coli and Klebsiella pneumoniae to amikacin, ciprofloxacin, cefotaxime, piperacillin/tazobactam and imipenem was relatively stable and did not significantly increase over time. The resistance of Pseudomonas aeruginosa strains to all antibiotics tested, including imipenem and meropenem, decreased over time. In contrast, the resistance of Acinetobacter baumannii strains to carbapenems increased from 4.7% to 14.7%. Methicillin-resistant Staphylococcus aureus (MRSA) significantly decreased from 65.2% in 2016 to 48.9% in 2020.

CONCLUSIONS

The bacterial prevalence and antibiotic resistance rates of E. coli, K. pneumoniae, P. aeruginosa, A. baumannii, S. aureus and MRSA were significantly lower than the national average.

HMGA1 induces FGF19 to drive pancreatic carcinogenesis and stroma formation

High mobility group A1 (HMGA1) chromatin regulators are upregulated in diverse tumors where they portend adverse outcomes, although how they function in cancer remains unclear. Pancreatic ductal adenocarcinomas (PDACs) are highly lethal tumors characterized by dense desmoplastic stroma composed predominantly of cancer-associated fibroblasts and fibrotic tissue. Here, we uncover an epigenetic program whereby HMGA1 upregulates FGF19 during tumor progression and stroma formation. HMGA1 deficiency disrupts oncogenic properties in vitro while impairing tumor inception and progression in KPC mice and subcutaneous or orthotopic models of PDAC. RNA sequencing revealed HMGA1 transcriptional networks governing proliferation and tumor-stroma interactions, including the FGF19 gene. HMGA1 directly induces FGF19 expression and increases its protein secretion by recruiting active histone marks (H3K4me3, H3K27Ac). Surprisingly, disrupting FGF19 via gene silencing or the FGFR4 inhibitor BLU9931 recapitulates most phenotypes observed with HMGA1 deficiency, decreasing tumor growth and formation of a desmoplastic stroma in mouse models of PDAC. In human PDAC, overexpression of HMGA1 and FGF19 defines a subset of tumors with extremely poor outcomes. Our results reveal what we believe is a new paradigm whereby HMGA1 and FGF19 drive tumor progression and stroma formation, thus illuminating FGF19 as a rational therapeutic target for a molecularly defined PDAC subtype.

Adipokine C1q/Tumor Necrosis Factor- Related Protein 3 (CTRP3) Attenuates Intestinal Inflammation Via Sirtuin 1/NF-κB Signaling

BACKGROUND & AIMS

The adipokine CTRP3 has anti-inflammatory effects in several nonintestinal disorders. Although serum CTRP3 is reduced in patients with inflammatory bowel disease (IBD), its function in IBD has not been established. Here, we elucidate the function of CTRP3 in intestinal inflammation.

METHODS

CTRP3 knockout (KO) and overexpressing transgenic (Tg) mice, along with their corresponding wild-type littermates, were treated with dextran sulfate sodium for 6-10 days. Colitis phenotypes and histologic data were analyzed. CTRP3-mediated signaling was examined in murine and human intestinal mucosa and mouse intestinal organoids derived from CTRP3 KO and Tg mice.

RESULTS

CTRP3 KO mice developed more severe colitis, whereas CTRP3 Tg mice developed less severe colitis than wild-type littermates. The deletion of CTRP3 correlated with decreased levels of Sirtuin-1 (SIRT1), a histone deacetylase, and increased levels of phosphorylated/acetylated NF-κB subunit p65 and proinflammatory cytokines tumor necrosis factor-α and interleukin-6. Results from CTRP3 Tg mice were inverse to those from CTRP3 KO mice. The addition of SIRT1 activator resveratrol to KO intestinal organoids and SIRT1 inhibitor Ex-527 to Tg intestinal organoids suggest that SIRT1 is a downstream effector of CTRP3-related inflammatory changes. In patients with IBD, a similar CTRP3/SIRT1/NF-κB relationship was observed.

CONCLUSIONS

CTRP3 expression levels correlate negatively with intestinal inflammation in acute mouse colitis models and patients with IBD. CTRP3 may attenuate intestinal inflammation via SIRT1/NF-κB signaling. The manipulation of CTRP3 signaling, including through the use of SIRT1 activators, may offer translational potential in the treatment of IBD.

HMGA1 chromatin regulators induce transcriptional networks involved in GATA2 and proliferation during MPN progression

Myeloproliferative neoplasms (MPNs) transform to myelofibrosis (MF) and highly lethal acute myeloid leukemia (AML), although the actionable mechanisms driving progression remain elusive. Here, we elucidate the role of the high mobility group A1 (HMGA1) chromatin regulator as a novel driver of MPN progression. HMGA1 is upregulated in MPN, with highest levels after transformation to MF or AML. To define HMGA1 function, we disrupted gene expression via CRISPR/Cas9, short hairpin RNA, or genetic deletion in MPN models. HMGA1 depletion in JAK2V617F AML cell lines disrupts proliferation, clonogenicity, and leukemic engraftment. Surprisingly, loss of just a single Hmga1 allele prevents progression to MF in JAK2V617F mice, decreasing erythrocytosis, thrombocytosis, megakaryocyte hyperplasia, and expansion of stem and progenitors, while preventing splenomegaly and fibrosis within the spleen and BM. RNA-sequencing and chromatin immunoprecipitation sequencing revealed HMGA1 transcriptional networks and chromatin occupancy at genes that govern proliferation (E2F, G2M, mitotic spindle) and cell fate, including the GATA2 master regulatory gene. Silencing GATA2 recapitulates most phenotypes observed with HMGA1 depletion, whereas GATA2 re-expression partially rescues leukemogenesis. HMGA1 transactivates GATA2 through sequences near the developmental enhancer (+9.5), increasing chromatin accessibility and recruiting active histone marks. Further, HMGA1 transcriptional networks, including proliferation pathways and GATA2, are activated in human MF and MPN leukemic transformation. Importantly, HMGA1 depletion enhances responses to the JAK2 inhibitor, ruxolitinib, preventing MF and prolonging survival in murine models of JAK2V617F AML. These findings illuminate HMGA1 as a key epigenetic switch involved in MPN transformation and a promising therapeutic target to treat or prevent disease progression.

Abstract 2765: The indoleamine 2,3 dioxygenase-1 pathway drives intratumoral B cell maintenance

Immunotherapy has revolutionized cancer treatment by improving survival in many cancer subtypes. While tumor infiltrating B (TIL-B) cells correlate with response to immunotherapy in selected solid tumors, they portend resistance to BRAF inhibitors in BRAF mutant melanoma. Thus, the mechanisms underlying TIL-B cell function within the tumor microenvironment have remained elusive. Here, we discovered that inhibition of the indoleamine 2,3 dioxygenase-1 (IDO1) pathway with D-1-methyl-tryptophan (D-1MT) markedly decreases TIL-B cells in a preclinical model of melanoma. Single cell RNA sequencing (scRNAseq) of murine melanoma demonstrate TIL-B cells are heterogeneous: while some B cells express markers consistent with an immune stimulatory phenotype, others express markers consistent with immune inhibitory function. D-1MT decreased splenic B cells and bone marrow derived B cell precursors in tumor bearing mice, suggesting that IDO1 pathway inhibition impedes B cell maturation. In four distinct human cancer subtypes, intratumoral IDO1 expression consistently correlates with high expression of a pan-B cell gene signature. Further, analysis of scRNAseq data from a cohort of patients with melanoma revealed that most TIL-B cells express IDO1. In mice, D-1MT also decreases intratumoral myeloid derived suppressor cells (MDSCs), which are essential for maintenance of TIL-B cells. Surprisingly, we found that D-1MT enhanced anti-tumor effects of the BRAF inhibitor, vemurafenib, in a preclinical model of BRAF mutant melanoma, suggesting that targeting B cells in this setting may be beneficial. Together, our data reveal a novel paradigm for the IDO1 pathway in regulating TIL-B cells, and uncovered IDO1 as a potential targetable mechanism of resistance to BRAF inhibition in melanoma.

Citation Format: Burles Avner Johnson, Adam K. Aragaki, Donna M. Williams, Ophelia Rogers, Li Luo, Lingling Xian, Lionel Chia, Noah M. Hahn, Stephen Desiderio, Theodore S. Johnson, David J. McConkey, Linda M.S. Resar. The indoleamine 2,3 dioxygenase-1 pathway drives intratumoral B cell maintenance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2765.

Abstract 2666: HMGA1: An epigenetic switch required for MPN progression by inducing GATA-2 and cell cycle progression through enhancer rewiring

Myeloproliferative neoplasms (MPN) are clonal hematopoietic stem cell (HSC) disorders characterized by hyperactive JAK/STAT signaling and increased risk of transformation to myelofibrosis (MF) and acute myeloid leukemia (AML). However, mechanisms driving progression remain elusive and outcomes are poor after transformation. The High Mobility Group A1 (HMGA1) gene encodes chromatin regulators which are enriched in normal stem cells and aberrantly overexpressed in diverse, refractory tumors. Hmga1 also drives clonal expansion and leukemogenesis in transgenic mice when overexpressed in lymphoid cells. To investigate HMGA1 in MPN, we compared gene expression in CD34+ stem and progenitors from MPN patients and healthy controls. HMGA1 is overexpressed in MPN, with highest levels after transformation to MF or AML. To assess HMGA1 function in MPN progression, we silenced HMGA1 gene expression in two cell lines derived from patients with JAK2V617F mutant MPN after transformation to leukemia. Strikingly, silencing HMGA1 disrupts cell cycle progression, proliferation, and clonogenicity in vitro while preventing leukemia engraftment in immunodeficient mice. To assess HMGA1 in more indolent disease, we crossed a JAK2V617F mouse model of chronic MPN to an Hmga1 deficient background. Loss of one Hmga1 allele was sufficient to prevent progression to MF. Further, Hmga1 heterozygosity mitigates thrombocytosis and splenomegaly, while preventing expansion in long-term HSC, granulocyte-macrophage progenitors, and megakaryocyte-erythroid progenitors. Hmga1 heterozygosity also prolongs survival in a JAK2V617F murine model of fulminant leukemia and early mortality. To define mechanisms underlying HMGA1 in MPN progression, we performed RNA sequencing in human MPN- AML cell lines and identified HMGA1-dependent transcriptional networks involved in cell fate decisions and cell cycle progression, including the master regulator gene, GATA-2. Mechanistically, HMGA1 occupies a developmental GATA-2 enhancer (+9.5) and recruits active histone marks (H3K4me1, H3K4me3) to increase GATA-2 expression. Silencing GATA-2 recapitulates the anti-leukemia phenotypes observed with HMGA1 silencing while GATA-2 re-expression partially rescues pro-leukemogenic phenotypes that occur in MPN-AML cells after HMGA1 depletion. In matched, primary peripheral blood monocytes from patients with MF, HMGA1 and GATA-2 are co-expressed and both become markedly up-regulated after transformation to AML. Epigenetic drugs predicted to target HMGA1 transcriptional networks synergize with JAK inhibitors to disrupt proliferation in MPN-AML cells. Together, our studies reveal a new paradigm whereby HMGA1 up-regulates GATA-2 to drive leukemic transformation in MPN and illuminate HMGA1 networks as novel therapeutic targets required for MPN progression.

Citation Format: Liping Li, Jung-Hyun Kim, Wenyan Lu, Donna Marie Williams, Lingling Xian, Joseph Kim, Ophelia Rogers, Raajit K. Rampal, Richard P. Koche, Leslie Cope, Karen Reddy, Daniel R. Matson, Joe Zhao, Jerry L. Spivak, Alison R. Moliterno, Linda Resar. HMGA1: An epigenetic switch required for MPN progression by inducing GATA-2 and cell cycle progression through enhancer rewiring [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2666.

Abstract 297: HMGA1 induces FGF-19 to foster tumor-stromal cell crosstalk and drive tumor progression in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinomas (PDACs) are highly lethal tumors characterized by a dense desmoplastic stroma comprised of cancer associated fibroblasts (CAFs) and fibrotic scar tissue. While stromal CAFs provide a barrier to therapy and release signals that foster tumor growth and invasion, the stroma also restrains tumor growth in murine models. The High Mobility Group A1 (HMGA1) chromatin remodeling gene encodes an oncofetal protein and epigenetic regulator that amplifies signals from the microenvironment to foster stem cell properties within intestinal epithelium. HMGA1 is also highly expressed during embryogenesis and in adult stem cells, but silenced postnatally in most differentiated cells. In diverse, aggressive cancers, HMGA1 becomes aberrantly re-expressed where high levels portend adverse clinical outcomes. In PDAC, HMGA1 protein is detected in late stage precursor lesions and invasive tumors, but not in normal pancreas nor in early precursor lesions. Furthermore, high HMGA1 levels correlate with poor differentiation status and decreased patient survival. Here, we discovered a novel epigenetic program mediated by HMGA1 that recruits CAFs to drive PDAC progression. We discovered that silencing HMGA1 in multiple PDAC cell lines halts proliferation and disrupts oncogenic properties, including migration, invasion, clonogenicity, and xenograft tumorigenesis. HMGA1 silencing also impairs three-dimensional sphere formation and depletes tumor initiator cells in limiting dilution assays. Through RNA sequencing analysis comparing PDAC cells overexpressing HMGA1 to those with HMGA1 silencing, we identified FGF-19 as a potential transcriptional target of HMGA1. HMGA1 binds specifically to the FGF-19 promoter and recruits the active histone mark, H3K4me3, to activate its expression. HMGA1 is also required for FGF-19 secretion from PDAC cells. Similar to HMGA1, silencing FGF-19 blocks oncogenic and cancer stem cell properties in vitro while disrupting tumorigenesis and depleting tumor initiator cells in vivo. In co-culture experiments, HMGA1 expressed in PDAC cells amplifies FGF-19 secretion, thereby stimulating CAF migration to tumor cells across a membrane. Silencing HMGA1 or FGF-19 prevents CAF recruitment to PDAC tumor cells. Furthermore, CAF recruitment is blocked by either FGF-19 blocking antibodies or an inhibitor to the FGF-19 receptor (FGR4). In murine models, silencing HMGA1 also decreases formation of a fibroblastic stroma. Moreover, overexpression of HMGA1 together with that of FGF-19 predict decreased survival in primary human PDAC. Our results reveal a novel paradigm whereby PDAC cells collaborate with stromal CAFs via HMGA1 and FGF-19 to drive tumor progression. These data also provide insight into mechanisms for tumor progression and illuminate FGF-19 as a rational therapeutic target in PDACs with up-regulation of HMGA1 and FGF-19.

Citation Format: Lionel Chia, Shuai Shuai, Lingling Xian, Jung-Hyun Kim, Ruitao Zhang, Tait Huso, David Huso, Leslie Cope, Karen Reddy, Linda Resar. HMGA1 induces FGF-19 to foster tumor-stromal cell crosstalk and drive tumor progression in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 297.

Light-Induced Renormalization of the Dirac Quasiparticles in the Nodal-Line Semimetal ZrSiSe

In nodal-line semimetals, linearly dispersing states form Dirac loops in the reciprocal space with a high degree of electron-hole symmetry and a reduced density of states near the Fermi level. The result is reduced electronic screening and enhanced correlations between Dirac quasiparticles. Here we investigate the electronic structure of ZrSiSe, by combining time- and angle-resolved photoelectron spectroscopy with ab initio density functional theory (DFT) complemented by an extended Hubbard model (DFT+U+V) and by time-dependent DFT+U+V. We show that electronic correlations are reduced on an ultrashort timescale by optical excitation of high-energy electrons-hole pairs, which transiently screen the Coulomb interaction. Our findings demonstrate an all-optical method for engineering the band structure of a quantum material.

One-dimensional flat bands in twisted bilayer germanium selenide

Experimental advances in the fabrication and characterization of few-layer materials stacked at a relative twist of small angle have recently shown the emergence of flat energy bands. As a consequence electron interactions become relevant, providing inroads into the physics of strongly correlated two-dimensional systems. Here, we demonstrate by combining large scale ab initio simulations with numerically exact strong correlation approaches that an effective one-dimensional system emerges upon stacking two twisted sheets of GeSe, in marked contrast to all moiré systems studied so far. This not only allows to study the necessarily collective nature of excitations in one dimension, but can also serve as a promising platform to scrutinize the crossover from two to one dimension in a controlled setup by varying the twist angle, which provides an intriguing benchmark with respect to theory. We thus establish twisted bilayer GeSe as an intriguing inroad into the strongly correlated physics of lowdimensional systems.

Abstract 2595: HMGA1 induces the HOXB13 developmental gene to drive tumor progression in androgen receptor negative, castrate-resistant prostate cancer

While High Mobility Group A1 (HMGA1) chromatin remodeling proteins are frequently dysregulated in diverse cancers, their molecular underpinnings in carcinogenesis remain poorly understood. HMGA1 are small, non-histone proteins that bind to AT-rich regions in DNA, bend chromatin, and recruit transcriptional complexes to modulate gene expression. Prior studies in prostate cancer (PCa) suggest that HMGA1 overexpression associates with higher pathologic grades and increases in HMGA1 protein levels correlate with metastatic potential in rat PCa cells. Overexpression of HMGA1 in human PCa cell lines induces unbalanced chromosomal rearrangements in vitro. Thus, we hypothesized that HMGA1 drives PCa progression through epigenetic reprogramming of transcriptional networks involved in development and chromosomal instability. To test this, we focused on androgen receptor (AR)-negative, castrate-resistant PCa (CRPC) cell lines as tumors with these features are resistant to therapy and associated with metastatic progression and early death. Here, we uncover a novel role for HMGA1 in regulating HOXB13 to drive tumor progression and cancer stem cell properties. We found that silencing HMGA1 in patient-derived metastatic cell lines (PC3-Epi, PC3-EMT, DU145) halts proliferation. Cell morphology changed most dramatically in PC3-EMT cells, transforming spindle-shaped, mesenchymal cells to more cuboidal, epithelial-like cells. Both migration and invasion were disrupted, but primarily in more invasive, mesenchymal cell lines (PC-EMT, DU145). Colony formation and 3D sphere formation were also blocked in all CRPC lines. Immunohistologic analysis in primary tumors revealed that HMGA1 nuclear staining associates with more advanced Gleason scores in PCa. To elucidate transcriptional networks downstream of HMGA1, RNA-seq was performed in PC3-EMT and PC3-Epi cell lines + HMGA1 silencing. Intriguingly, HMGA1 regulates pathways involved in inflammation in the more epithelial PC3-Epi cells, while pathways involved in mitosis, cell cycle progression, DNA damage, and checkpoint regulation predominated in the mesenchymal PC3-EMT cells. Pathways involved in proliferation and development were regulated by HMGA1 in both settings. We focused on HOXB13, a developmental gene linked to cell fate and prostate carcinogenesis. Both HOXB13 and HMGA1 are co-regulated in CRPC cell lines at the gene expression and protein level. HMGA1 occupies at least 1 site within the HOXB13 promoter region by chromatin immunoprecipitation. Strikingly, silencing HOXB13recapitulates HMGA1 phenotypes, impairing proliferation, colony formation, and 3D sphere formation. These findings reveal a novel role for HMGA1 in CRPC progression by dysregulating developmental networks. Together, these results also suggest that targeting the HMGA1-HOXB13 pathway could be effective therapy in CRPC.

Citation Format: Lionel Chia, Guangjing Zhu, Mikhail Gorbounov, Lingling Xian, Briyana Chisholm, Mohammad Heydarian, Dorhyun Johng, William B. Isaacs, Karen Reddy, Linda S. Resar. HMGA1 induces the HOXB13 developmental gene to drive tumor progression in androgen receptor negative, castrate-resistant prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2595.

Genetic Engineering of Primary Mouse Intestinal Organoids Using Magnetic Nanoparticle Transduction Viral Vectors for Frozen Sectioning

Intestinal organoid cultures provide a unique opportunity to investigate intestinal stem cell and crypt biology in vitro, although efficient approaches to manipulate gene expression in organoids have made limited progress in this arena. While CRISPR/Cas9 technology allows for precise genome editing of cells for organoid generation, this strategy requires extensive selection and screening by sequence analysis, which is both time-consuming and costly. Here, we provide a detailed protocol for efficient viral transduction of intestinal organoids. This approach is rapid and highly efficient, thus decreasing the time and expense inherent in CRISPR/Cas9 technology. We also present a protocol to generate frozen sections from intact organoid cultures for further analysis with immunohistochemical or immunofluorescent staining, which can be used to confirm gene expression or silencing. After successful transduction of viral vectors for gene expression or silencing is achieved, intestinal stem cell and crypt function can be rapidly assessed. Although most organoid studies employ in vitro assays, organoids can also be delivered to mice for in vivo functional analyses. Moreover, our approaches are advantageous for predicting therapeutic responses to drugs because currently available therapies generally function by modulating gene expression or protein function rather than altering the genome.

Abstract 4494: HMGA1 drives tumor progression and recruits cancer-associated fibroblasts in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinomas (PDACs) are highly lethal tumors for which there are no effective therapies. Emerging evidence suggests that the tumor stroma interacts with the cancer cells to induce cancer stem cell properties and drive tumor progression. In PDAC, the fibroblast stroma also provides a dense barrier preventing cytotoxic therapy from reaching PDAC cells. We previously discovered that high levels of High Mobility Group A1 (HMGA1) protein predict decreased survival in primary PDAC. Here, we report a novel role for HMGA1-FGF19 in mediating tumor-stromal interactions and tumor progression. Silencing HMGA1 in PDAC cell lines or low-passge, patient-derived cells abruptly halts proliferation. Spindle-shaped, mesenchymal cells became reprogrammed into cuboidal, more epithelial-like cells. Sensitivity to gemcitabine was enhanced and colony formation, migration, invasion, and three-dimensional (3D) sphere formation were all disrupted in cells with HMGA1 knock-down. Silencing HMGA1 also disrupted xenograft tumorigenesis and depleted cancer stem cells/tumor-initiator cells in limiting dilution tumorigenicity assays. To elucidate underlying molecular mechanisms mediating these striking phenotypes, we performed RNA-seq after silencing HMGA1 in invasive, highly metastatic, low-passage patient-derived PDAC cells (10.7). Among the genes regulated by HMGA1 were those encoding proteins involved in tumor-stromal signaling, including the fibroblast growth factor 19 (FGF19). The FGF19 gene is highly expressed in GI tumors (liver, colon, PDAC) and transgenic mice overexpressing Fgr15 (the murine homolog) in hepatocytes develop hepatocellular carcinoma (HCC). FGF19 also correlates with poor outcomes in human HCC and colon cancer, although it's role in PDAC was unknown. Here, we found that FGF19 expression is dependent upon HMGA1 in 3 different PDAC cell lines; silencing HMGA1 represses FGF19 in these cells. HMGA1 also binds directly to the FGF19 promoter at 2 predicted DNA binding sites as assessed by chromatin immunoprecipiation. To determine whether FGF19 plays a functional role in HMGA1-mediated tumor progression and cancer stem cell properties, we silenced FGF19 in PDAC cells. Similar to our results with HMGA1, silencing FGF19 impaired PDAC growth and 3D sphere formation in vitro. Because fibroblast growth factors interact with fibroblasts, we determined whether the HMGA1-FGF19 pathway was involved in tumor cell – stromal crosstalk. PDAC 10.7 cells recruit cancer-associated fibroblasts (CAFs) in a co-culture system, although this recruitment was abrogated when HMGA1 was silenced. CAF migration was also disrupted by anti-human FGF19 neutralizing antibodies. Together, these findings indicate that HMGA1 drive tumor progression and cancer stem cell properties through FGF19 and suggest that targeting the HMGA1-FGF19 pathway maybe efficaceous in PDAC.

Citation Format: Shuai Shuai, Lingling Xian, Tait Huso, Karen Reddy, Linda Resar. HMGA1 drives tumor progression and recruits cancer-associated fibroblasts in pancreatic ductal adenocarcinoma [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 4494.

Abstract 3352: HMGA1 chromatin remodeling protein induces HOXB13 to drive cancer stem cell properties and tumor progression in prostate cancer models

Increasing evidence suggests that cancer cells undergo chromatin remodeling and epigenetic reprogramming during tumor progression, although the underlying mechanisms remain poorly understood. The High Mobility Group A1 (HMGA1) chromatin binding protein is an architectural transcription factor that binds to AT-rich regions in DNA where it displaces histone HI and recruits transcriptional complexes to modulate gene expression. The HMGA1 gene is highly expressed during embryogenesis and in adult stem cells, but silenced postnatally in differentiated tissues. HMGA1 becomes re-expressed in most high-grade cancers and high levels portend adverse clinical outcomes. In prostate cancer (PCa), HMGA1 overexpression and protein immunoreactivity associates with high pathologic grade, although its function in this setting is unknown. To gain mechanistic into the role of HMGA1 in PCa, we silenced HMGA1 in 2 human PCa cell lines: 1) PC3-Epi, a PCa clone selected for epithelial properties, and 2) PC3-EMT, a more invasive PCa clone with mesenchymal properties. Silencing HMGA1 halts proliferation in both PC3-Epi and PC3-EMT cells. Cell morphology changed most dramatically in the PC3-EMT cells, transforming spindle-shaped, mesenchymal cells to more cuboidal, epithelial-like cells. Both migration and invasion were disrupted, but only in the more invasive PC-EMT cells. Colony formation and the stem cell property, three-dimensional (3D) sphere formation, were also blocked in cells with HMGA1 knock-down. To elucidate transcriptional networks downstream of HMGA1, RNA-seq was performed in both cell lines + HMGA1 silencing. We identified genes involved in cell signaling, protein synthesis, post-translational modifications, cell motility, mitotic spindle formation, and development. We focused on the HOXB13 developmental gene, which encodes a transcription factor involved in prostate development. Intriguingly, HOXB13 germline mutations are linked to familial PCa. We found that HOXB13 and HMGA1 are co-regulated in PCa cells by quantitative RT-PCR. HMGA1 occupies 2 sites within the HOXB13 promoter region by chromatin immunoprecipitation. Strikingly, silencing HOXB13 recapitulates HMGA1 phenotypes, impairing proliferation, colony formation, and 3D sphere formation. This work not only reveals a novel role for HMGA1 in regulating both cancer stem cell properties and tumor progression in PCa through HOXB13, but also suggests that targeting the HMGA1-HOXB13 pathway could be effective therapy in invasive PCa.

Citation Format: Lionel Chia, Lingling Xian, Guangjing Zhu, Mohammad Heydarian, William B. Issacs, Karen Reddy, Linda Smith Resar. HMGA1 chromatin remodeling protein induces HOXB13 to drive cancer stem cell properties and tumor progression in prostate cancer models [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 3352.

Lessons from the Crypt: HMGA1-Amping up Wnt for Stem Cells and Tumor Progression

High mobility group A1 (HMGA1) chromatin remodeling proteins are enriched in aggressive cancers and stem cells, although their common function in these settings has remained elusive until now. Recent work in murine intestinal stem cells (ISC) revealed a novel role for Hmga1 in enhancing self-renewal by amplifying Wnt signaling, both by inducing genes expressing Wnt agonist receptors and Wnt effectors. Surprisingly, Hmga1 also "builds" a stem cell niche by upregulating Sox9, a factor required for differentiation to Paneth cells; these cells constitute an epithelial niche by secreting Wnt and other factors to support ISCs. HMGA1 is also highly upregulated in colon cancer compared with nonmalignant epithelium and SOX9 becomes overexpressed during colon carcinogenesis. Intriguingly, HMGA1 is overexpressed in diverse cancers with poor outcomes, where it regulates developmental genes. Similarly, HMGA1 induces genes responsible for pluripotency and self-renewal in embryonic stem cells. These findings demonstrate that HMGA1 maintains Wnt and other developmental transcriptional networks and suggest that HMGA1 overexpression fosters carcinogenesis and tumor progression through dysregulation of these pathways. Studies are now needed to determine more precisely how HMGA1 modulates chromatin structure to amplify developmental genes and how to disrupt this process in cancer therapy. Cancer Res; 78(8); 1890-7. ©2018 AACR.

Abstract 5019: HMGA1 amplifies Wnt signaling and expands the intestinal stem cell compartment to drive premalignant polyposis in transgenic mice

Emerging evidence suggests that cancer cells undergo chromatin remodeling and epigenetic reprogramming to co-opt stem cell properties and drive tumor progression. The HMGA1 chromatin remodeling protein is an architectural transcription factor that binds to DNA at AT-rich sequences where it “opens” chromatin, recruits transcriptional complexes, and modulates gene expression. The HMGA1 gene is highly expressed during embryogenesis and in adult stem cells, but silenced postnatally in differentiated tissues. HMGA1 becomes re-expressed in most high-grade cancers and high levels portend adverse clinical outcomes. In colon cancer, HMGA1 is among the genes most highly overexpressed compared to normal intestinal epithelium. We previously reported that HMGA1 drives tumor progression in colon cancer by inducing stem cell genes involved in an epithelial-mesenchymal transition. We also discovered that Hmga1 transgenic mice develop marked proliferative changes and pre-malignant polyposis in the intestinal epithelium. To determine how Hmga1 functions in the intestines during tissue homeostasis and carcinogenesis, we examined in transgenic mice and organoid models. Here, we uncover a novel role for Hmga1 in maintaining the intestinal stem cell (ISC) pool and Paneth cell niche. Hmga1 is required by ISCs to organize into three-dimensional organoids in vitro; silencing Hmga1 disrupts organoid formation and bud development. Conversely, overexpression of Hmga1 increases organoid formation, bud development, and replating efficiency, suggesting that Hmga1 enhances ISC function and/or number. We therefore crossed the Hmga1 transgenic mice onto the Lgr5-EGFP background to enumerate ISCs and found that Hmga1 expands the ISC compartment. To determine how this occurs, we performed in vivo imaging and discovered that Hmga1 enhances self-renewal of ISCs. Mechanistically, we found that Hmga1 amplifies Wnt/β-catenin signaling by inducing genes encoding both Wnt agonist receptors and downstream Wnt target genes. Surprisingly, Hmga1 also expands the Paneth cell niche, which is comprised of terminally differentiated crypt cells that secrete Wnt to support ISCs. Because Paneth cells require Sox9 for development, we determined whether Hmga1 regulates its expression. Hmga1 binds directly to the Sox9 promoter at 2 AT-rich sites to activate its expression. In human colonic epithelium, HMGA1 and SOX9 are positively correlated, and both become markedly up-regulated in colon carcinogenesis. This work not only provides new insights into the role of Hmga1 in intestinal homeostasis by maintaining both the stem cell pool and epithelial niche compartment, but also suggests that deregulated Hmga1 perturbs this equilibrium during polyposis and carcinogenesis. Our results also highlight the HMGA1-WNT-SOX9 pathway as rational therapeutic target in colon carcinogenesis.

Citation Format: Lingling Xian, Dan Georgess, Li Luo, Lionel Chia, Qihua Gu, Tait Huso, Amy Belton, David Huso, Andrew Ewald, Linda M.S. Resar. HMGA1 amplifies Wnt signaling and expands the intestinal stem cell compartment to drive premalignant polyposis in transgenic mice [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 5019. doi:10.1158/1538-7445.AM2017-5019

Abstract LB-224: A novel model of pediatric spinal ependymoma using conditionally reprogrammed cells from a primary tumor demonstrates aberrant expression of HMGA, HOX, MYC and other Wnt target genes

Pediatric spinal ependymomas are rare tumors of the central nervous system with limited treatment options. Successful outcomes depend primarily upon the extent of surgical resection, although significant impairment is common, particularly in children with developing nervous systems. Because these tumors are uncommon, there are no established tumor models nor are there many studies to define underlying molecular lesions. Here, we describe an innovative spinal ependymoma (SE) tumor model based on the recent discovery that primary carcinoma cells can be cultured indefinitely ex vivo on fibroblast feeder cells in the presence of a rho kinase inhibitor; these cells are denoted conditionally reprogrammed cells (CRCs). In prior studies, CRCs form spheres in vitro, replicate tumor pathology as xenografts in vivo, and predict drug responses to the primary tumor. We therefore adopted this strategy to generate a cell line from a 12 year-old girl with a spinal myxopapillary ependymoma. The cell line and primary tumor are of human origin and identical with respect to short tandem repeat (STR) analysis. Using targeted gene expression analysis, we discovered that genes encoding the of High Mobility Group Protein AT-hook 1 (HMGA1), High Mobility Group Protein AT-hook 2 (HMGA2), cMYC, HOXB13, and HOXA10 proteins are all up-regulated compared to their expression in spinal cord tissue from a normal individual. In primary pediatric tumors, HMGA1 gene expression was also higher in spinal ependymomas as compared to supratentorial or posterior fossa ependymomas. There was also a significant positive correlation between HMGA1 and HOX genes, including HOXA10, HOXD13, HOXD1, and HOXB7 in primary tumors. In addition, HMGA1 and cMYC, together with other Wnt target genes, were positively correlated in primary spinal ependymoma. Pathway analysis showed that HMGA1 expression correlated with the following pathways: 1) metabolic pathways, 2) osteoclast differentiation, 3) MAPK signaling, and, 4) Neurotropin signaling. Studies are underway to generate additional cell lines from primary tumor samples and to elucidate the mechanisms that account for up-regulation in HMGA1, HOX and Wnt genes. We will harness this information to identify novel therapeutic targets and agents for children and young adults with spinal ependymoma.

Citation Format: Li Z. Luo, Ewa Krawczyk, Anbarasu Lourdusamy, Lisa C. Storer, Lingling Xian, Kenneth J. Cohen, Richard Schlegel, Richard Grundy, Linda Resar. A novel model of pediatric spinal ependymoma using conditionally reprogrammed cells from a primary tumor demonstrates aberrant expression of HMGA, HOX, MYC and other Wnt target genes [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 LB-224. doi:10.1158/1538-7445.AM2017-LB-224

HMGA1 amplifies Wnt signalling and expands the intestinal stem cell compartment and Paneth cell niche

High-mobility group A1 (Hmga1) chromatin remodelling proteins are enriched in intestinal stem cells (ISCs), although their function in this setting was unknown. Prior studies showed that Hmga1 drives hyperproliferation, aberrant crypt formation and polyposis in transgenic mice. Here we demonstrate that Hmga1 amplifies Wnt/β-catenin signalling to enhance self-renewal and expand the ISC compartment. Hmga1 upregulates genes encoding both Wnt agonist receptors and downstream Wnt effectors. Hmga1 also helps to 'build' an ISC niche by expanding the Paneth cell compartment and directly inducing Sox9, which is required for Paneth cell differentiation. In human intestine, HMGA1 and SOX9 are positively correlated, and both become upregulated in colorectal cancer. Our results define a unique role for Hmga1 in intestinal homeostasis by maintaining the stem cell pool and fostering terminal differentiation to establish an epithelial stem cell niche. This work also suggests that deregulated Hmga1 perturbs this equilibrium during intestinal carcinogenesis.

The High Mobility Group A1 (HMGA1) Transcriptome in Cancer and Development

BACKGROUND & OBJECTIVES

Chromatin structure is the single most important feature that distinguishes a cancer cell from a normal cell histologically. Chromatin remodeling proteins regulate chromatin structure and high mobility group A (HMGA1) proteins are among the most abundant, nonhistone chromatin remodeling proteins found in cancer cells. These proteins include HMGA1a/HMGA1b isoforms, which result from alternatively spliced mRNA. The HMGA1 gene is overexpressed in cancer and high levels portend a poor prognosis in diverse tumors. HMGA1 is also highly expressed during embryogenesis and postnatally in adult stem cells. Overexpression of HMGA1 drives neoplastic transformation in cultured cells, while inhibiting HMGA1 blocks oncogenic and cancer stem cell properties. Hmga1 transgenic mice succumb to aggressive tumors, demonstrating that dysregulated expression of HMGA1 causes cancer in vivo. HMGA1 is also required for reprogramming somatic cells into induced pluripotent stem cells. HMGA1 proteins function as ancillary transcription factors that bend chromatin and recruit other transcription factors to DNA. They induce oncogenic transformation by activating or repressing specific genes involved in this process and an HMGA1 "transcriptome" is emerging. Although prior studies reveal potent oncogenic properties of HMGA1, we are only beginning to understand the molecular mechanisms through which HMGA1 functions. In this review, we summarize the list of putative downstream transcriptional targets regulated by HMGA1. We also briefly discuss studies linking HMGA1 to Alzheimer's disease and type-2 diabetes.

CONCLUSION

Further elucidation of HMGA1 function should lead to novel therapeutic strategies for cancer and possibly for other diseases associated with aberrant HMGA1 expression.

Fecal Metabolome in Hmga1 Transgenic Mice with Polyposis: Evidence for Potential Screen for Early Detection of Precursor Lesions in Colorectal Cancer

Because colorectal cancer (CRC) remains a leading cause of cancer mortality worldwide, more accessible screening tests are urgently needed to identify early stage lesions. We hypothesized that highly sensitive, metabolic profile analysis of stool samples will identify metabolites associated with early stage lesions and could serve as a noninvasive screening test. We therefore applied traveling wave ion mobility mass spectrometry (TWIMMS) coupled with ultraperformance liquid chromatography (UPLC) to investigate metabolic aberrations in stool samples in a transgenic model of premalignant polyposis aberrantly expressing the gene encoding the high mobility group A (Hmga1) chromatin remodeling protein. Here, we report for the first time that the fecal metabolome of Hmga1 mice is distinct from that of control mice and includes metabolites previously identified in human CRC. Significant alterations were observed in fatty acid metabolites and metabolites associated with bile acids (hypoxanthine xanthine, taurine) in Hmga1 mice compared to controls. Surprisingly, a marked increase in the levels of distinctive short, arginine-enriched, tetra-peptide fragments was observed in the transgenic mice. Together these findings suggest that specific metabolites are associated with Hmga1-induced polyposis and abnormal proliferation in intestinal epithelium. Although further studies are needed, these data provide a compelling rationale to develop fecal metabolomic analysis as a noninvasive screening tool to detect early precursor lesions to CRC in humans.

Abstract 1704: High mobility group A1 chromatin remodeling protein expands the intestinal stem cell compartment and Paneth cell niche through Wnt/β-catenin signaling and Sox9

The High Mobility Group A1 (HMGA1) gene is overexpressed in most poorly differentiated cancers and high levels portend adverse clinical outcomes, although the molecular mechanisms through which it functions are poorly understood. HMGA1 encodes the HMGA1a and HMGA1b chromatin remodeling proteins, which modulate gene expression by bending chromatin and orchestrating the assembly of transcription factor complexes to DNA. HMGA1 is highly expressed during embryogenesis, but silenced in adult, differentiated tissues. Postnatally, HMGA1 expression is maintained in adult stem cells, such as intestinal stem cells (ISCs); however, its role in this setting has been unknown. Here, we report that Hmga1 overexpression in ISCs of transgenic mice drives expansion in the ISC compartment leading to hyperproliferation, aberrant crypt formation, and polyposis. Surprisingly, Hmga1 transgenic mice also exhibit marked expansion in terminally differentiated Paneth cells, which comprise an epithelial cell niche for ISCs. To dissect the mechanisms mediating these phenotypes, we generated three-dimensional (3D) intestinal organoids with varied expression of Hmga1. Strikingly, silencing Hmga1 in wildtype crypt cells disrupts their ability to organize into functional 3D organoids with bud formation, while crypt cells expressing ectopic Hmga1 exhibit enhanced organoid formation with increased ISC number, proliferation, and bud development. Because Wnt/β-catenin signaling is central to ISC function, we determined whether Hmga1 modulates this pathway. β-catenin protein is increased in the crypts of the Hmga1 transgenic mice and organoids. Hmga1 amplifies Wnt/β-catenin signaling by inducing both genes that encode Wnt cell surface receptors and target genes downstream of Wnt/β-catenin. Hmga1 also directly up-regulates Sox9, which is required for terminal differentiation to Paneth cells. This is the first example of Hmga1 fostering terminal differentiation to establish a stem cell niche. In human intestinal epithelium, HMGA1 and SOX9 are highly correlated (P = 0.008), and both become up-regulated in carcinogenesis. These results reveal a novel role for Hmga1 in intestinal homeostasis by maintaining both the stem cell pool and epithelial niche compartment and suggest that deregulated Hmga1 perturbs this equilibrium during intestinal carcinogenesis.

Citation Format: Lingling Xian, Tait Huso, Amy Belton, David Huso, Linda M. S. Resar. High mobility group A1 chromatin remodeling protein expands the intestinal stem cell compartment and Paneth cell niche through Wnt/β-catenin signaling and Sox9. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1704.

The High Mobility Group A1 (HMGA1) gene is highly overexpressed in human uterine serous carcinomas and carcinosarcomas and drives Matrix Metalloproteinase-2 (MMP-2) in a subset of tumors

OBJECTIVES

Although uterine cancer is the fourth most common cause for cancer death in women worldwide, the molecular underpinnings of tumor progression remain poorly understood. The High Mobility Group A1 (HMGA1) gene is overexpressed in aggressive cancers and high levels portend adverse outcomes in diverse tumors. We previously reported that Hmga1a transgenic mice develop uterine tumors with complete penetrance. Because HMGA1 drives tumor progression by inducing MatrixMetalloproteinase (MMP) and other genes involved in invasion, we explored the HMGA1-MMP-2 pathway in uterine cancer.

METHODS

To investigate MMP-2 in uterine tumors driven by HMGA1, we used a genetic approach with mouse models. Next, we assessed HMGA1 and MMP-2 expression in primary human uterine tumors, including low-grade carcinomas (endometrial endometrioid) and more aggressive tumors (endometrial serous carcinomas, uterine carcinosarcomas/malignant mesodermal mixed tumors).

RESULTS

Here, we report for the first time that uterine tumor growth is impaired in Hmga1a transgenic mice crossed on to an Mmp-2 deficient background. In human tumors, we discovered that HMGA1 is highest in aggressive carcinosarcomas and serous carcinomas, with lower levels in the more indolent endometrioid carcinomas. Moreover, HMGA1 and MMP-2 were positively correlated, but only in a subset of carcinosarcomas. HMGA1 also occupies the MMP-2 promoter in human carcinosarcoma cells.

CONCLUSIONS

Together, our studies define a novel HMGA1-MMP-2 pathway involved in a subset of human carcinosarcomas and tumor progression in murine models. Our work also suggests that targeting HMGA1 could be effective adjuvant therapy for more aggressive uterine cancers and provides compelling data for further preclinical studies.

Role of TGF-β Signaling in Coupling Bone Remodeling

TGF-β signaling plays a key role in the temporal and spatial regulation of bone remodeling. During osteoclast bone resorption, TGF-β is released from the bone matrix and activated. Active TGF-β recruits mesenchymal stem cells to the bone resorption pit through the SMAD signaling pathway. Mesenchymal stem cells undergo osteoblast differentiation and deposit new bone filling in the resorption pit and maintaining the structural integrity of the skeleton. Thus, TGF-β signaling plays a key role in the coupling process and disruptions to the TGF-β signaling pathway lead to loss of skeletal integrity. This chapter describes methods on how to quantitate bone matrix TGF-β and assess its role in mesenchymal stem cell migration both in vitro and in vivo.

RANTES and SDF-1 Are Keys in Cell-based Therapy of TMJ Osteoarthritis

The present study aimed to investigate the therapeutic effect of injections of local bone marrow mesenchymal stem cells (BMSCs) on osteoarthritis (OA) of the temporomandibular joint (TMJ) and to explore the role of stromal cell-derived factor 1 (SDF-1) and regulated on activation, normal T-cell expressed and secreted (RANTES) in this effect. Fundamentally, OA of the TMJ was induced by unilateral anterior crossbite in mice. Exogenous green fluorescent protein-labeled BMSCs (GFP-BMSCs) were weekly injected into the TMJ region for 4, 8, and 12 wk. The reparative effects of exogenous GFP-BMSCs were investigated by morphological observation and micro-computed tomography. The differentiation of GFP-BMSCs in the cartilage was examined by double immunofluorescence of GFPs with type II collagen, and the expression of related factors in the condylar cartilage was quantified by real-time polymerase chain reaction. The role of RANTES and SDF-1 in the therapeutic effect of exogenous BMSCs was examined by both in vitro and in vivo studies. The OA cartilage of the TMJ displays a synchronous increase in SDF-1 and RANTES expression and a higher capability of attracting the migration of GFP-BMSCs. The implanted GFP-BMSCs differentiated into type II collagen-positive cells and reversed cartilage degradation and subchondral bone loss in mice with OA of the TMJ. The migration of GFP-BMSCs towards OA cartilage and the rescuing effect of GFP-BMSC injections were impaired by the inhibitors of C-X-C chemokine receptor type 4 (CXCR4) and C-C chemokine receptor type 1 (CCR1), which are the receptors of SDF-1 and RANTES, respectively. Our data indicated that SDF-1/CXCR4 and RANTES/CCR1 signals are pivotal and function synergistically in the recruitment of GFP-BMSCs towards degraded cartilage in mice OA of the TMJ.

HMGA1 drives metabolic reprogramming of intestinal epithelium during hyperproliferation, polyposis, and colorectal carcinogenesis

Although significant progress has been made in the diagnosis and treatment of colorectal cancer (CRC), it remains a leading cause of cancer death worldwide. Early identification and removal of polyps that may progress to overt CRC is the cornerstone of CRC prevention. Expression of the High Mobility Group A1 (HMGA1) gene is significantly elevated in CRCs as compared with adjacent, nonmalignant tissues. We investigated metabolic aberrations induced by HMGA1 overexpression in small intestinal and colonic epithelium using traveling wave ion mobility mass spectrometry (TWIMMS) in a transgenic model in which murine Hmga1 was misexpressed in colonic epithelium. To determine if these Hmga1-induced metabolic alterations in mice were relevant to human colorectal carcinogenesis, we also investigated tumors from patients with CRC and matched, adjacent, nonmalignant tissues. Multivariate statistical methods and manual comparisons were used to identify metabolites specific to Hmga1 and CRC. Statistical modeling of data revealed distinct metabolic patterns in Hmga1 transgenics and human CRC samples as compared with the control tissues. We discovered that 13 metabolites were specific for Hmga1 in murine intestinal epithelium and also found in human CRC. Several of these metabolites function in fatty acid metabolism and membrane composition. Although further validation is needed, our results suggest that high levels of HMGA1 protein drive metabolic alterations that contribute to CRC pathogenesis through fatty acid synthesis. These metabolites could serve as potential biomarkers or therapeutic targets.

PTH receptor signaling in osteoblasts regulates endochondral vascularization in maintenance of postnatal growth plate

Longitudinal growth of postnatal bone requires precise control of growth plate cartilage chondrocytes and subsequent osteogenesis and bone formation. Little is known about the role of angiogenesis and bone remodeling in maintenance of cartilaginous growth plate. Parathyroid hormone (PTH) stimulates bone remodeling by activating PTH receptor (PTH1R). Mice with conditional deletion of PTH1R in osteoblasts showed disrupted trabecular bone formation. The mice also exhibited postnatal growth retardation with profound defects in growth plate cartilage, ascribable predominantly to a decrease in number of hypertrophic chondrocytes, resulting in premature fusion of the growth plate and shortened long bones. Further characterization of hypertrophic zone and primary spongiosa revealed that endochondral angiogenesis and vascular invasion of the cartilage were impaired, which was associated with aberrant chondrocyte maturation and cartilage development. These studies reveal that PTH1R signaling in osteoblasts regulates cartilaginous growth plate for postnatal growth of bone.

ATP-binding cassette transporter A1 (ABCA1) promotes arsenic tolerance in human cells by reducing cellular arsenic accumulation

Arsenic is a toxic element widely distributed in nature, such as water and soil. To survive this metalloid in the environment, nearly all organisms develop strategies to tolerate arsenic toxicity to some degree. Some arsenic-resistance genes have been identified in bacteria and yeast, but for mammals, especially humans, these genes are largely unknown. The aim of the present study was to identify these genes and benefit our intervention of arsenic resistance. We first established a human arsenic-resistant ECV-304 (AsRE) cell line and then used suppression subtractive hybridization and microarray analysis to identify arsenic-resistant genes in these cells. Of the significantly upregulated genes, three ATP-binding cassette (ABC) subfamily members, namely ABCA1, ABCE1 and ABCF1, were chosen for further study with RNA interference and overexpression analyses. The 3-(4,5-dimethyl-2 thiazoyl)-2,5-diphenyl-2H-tetrazolium bromide assay was used to determine the cell survival rate and the IC50 , whereas atomic fluorescence spectrophotometry was used to determine intracellular arsenic levels. We found that among the three ABC genes, only when ABCA1 gene expression was silenced did cells obviously lose their arsenic tolerance. The arsenic accumulation in ABCA1 deficiency AsRE cells was greater than that in wild type AsRE cells. Overexpression of ABCA1 in HeLa cells decreased arsenic accumulation in the cells and the cells were more resistant to As(III) than control cells transfected with empty vector. These results suggest a new functional role for ABCA1 in the development of arsenic resistance in human cells.

Quantitative assessment of the effects of the EPHX1 Tyr113His polymorphism on lung and breast cancer

The association between the microsomal epoxide hydrolase 1 gene (EPHX1) Tyr113His polymorphism and lung cancer and breast cancer risk has been reported in many recent studies, but there is no consensus among the results. Thus, we examined the association between the EPHX1 Tyr113His polymorphism and lung cancer through a meta-analysis. A comprehensive literature search was performed using the Pubmed and Embase databases. Odds ratios with 95% confidence intervals were used to assess the strength of associations. Our meta-analysis suggested that the Tyr113His polymorphism was associated with lung cancer risk in Asians under 3 genetic models, including a C vs T, CC vs TT, and recessive model. However, the risk was decreased in Caucasians under the genetic models, including a C vs T, CC vs TT, or CT vs TT, dominant, and recessive model. In contrast, there was no association with breast cancer risk for any of the genetic models. Our meta-analysis suggested that the EPHX1 Tyr113His polymorphism may be a risk factor for lung cancer in Asians, whereas it may be a decreased risk factor among Caucasians. However, this polymorphism was not found to be associated with breast cancer.

Functional effects of TGF-β1 on mesenchymal stem cell mobilization in cockroach allergen-induced asthma

Mesenchymal stem cells (MSCs) have been suggested to participate in immune regulation and airway repair/remodeling. TGF-β1 is critical in the recruitment of stem/progenitor cells for tissue repair, remodeling, and cell differentiation. In this study, we sought to investigate the role of TGF-β1 in MSC migration in allergic asthma. We examined nestin expression (a marker for MSCs) and TGF-β1 signaling activation in airways in cockroach allergen extract (CRE)-induced mouse models. Compared with control mice, there were increased nestin(+) cells in airways and higher levels of active TGF-β1 in serum and p-Smad2/3 expression in lungs of CRE-treated mice. Increased activation of TGF-β1 signaling was also found in CRE-treated MSCs. We then assessed MSC migration induced by conditioned medium from CRE-challenged human epithelium in air/liquid interface culture in Transwell assays. MSC migration was stimulated by epithelial-conditioned medium, but was significantly inhibited by either TGF-β1-neutralizing Ab or TβR1 inhibitor. Intriguingly, increased migration of MSCs from blood and bone marrow to the airway was also observed after systemic injection of GFP(+) MSCs and from bone marrow of Nes-GFP mice following CRE challenge. Furthermore, TGF-β1-neutralizing Ab inhibited the CRE-induced MSC recruitment, but promoted airway inflammation. Finally, we investigated the role of MSCs in modulating CRE-induced T cell response and found that MSCs significantly inhibited CRE-induced inflammatory cytokine secretion (IL-4, IL-13, IL-17, and IFN-γ) by CD4(+) T cells. These results suggest that TGF-β1 may be a key promigratory factor in recruiting MSCs to the airways in mouse models of asthma.

Overexpressed TGF-β in subchondral bone leads to mandibular condyle degradation

Emerging evidence has implied that subchondral bone plays an important role during osteoarthritis (OA) pathology. This study was undertaken to investigate whether abnormalities of the condylar subchondral bone lead to temporomandibular joint (TMJ) OA. We used an osteoblast-specific mutant TGF-β1 transgenic mouse, the CED mouse, in which high levels of active TGF-β1 occur in bone marrow, leading to abnormal bone remodeling. Subchondral bone changes in the mandibular condyles were investigated by micro-CT, and alterations in TMJ condyles were confirmed by histopathological and immunohistochemical analysis. Abnormalities in the condylar subchondral bone, characterized as fluctuant bone mineral density and microstructure and increased but uncoupled activity of osteoclasts and osteoblasts, were apparent in the 1- and 4-month CED mouse groups, while obvious cartilage degradation, in the form of cell-free regions and proteoglycan loss, was observed in the 4-month CED group. In addition, increased numbers of apoptotic chondrocytes and MMP9- and VEGF-positive chondrocytes were observed in the condylar cartilage in the 4-month CED group, but not in the 1-month CED group, compared with their respective age-matched controls. This study demonstrated that progressive degradation of mandibular condylar cartilage could be induced by the abnormal remodeling of the underlying subchondral bone during TMJOA progression.

Electrolytic partitioning of uranium and plutonium based on a new type of electrolytic mixer-settler

The design of a new type of electroreduction mixer-settler for the partitioning of uranium and plutonium during the Purex process, which is featured with E-shaped cathodes and U-shaped anodes in settling chamber, is described and the operational results achieved using this equipment are presented. The results show that this new type of mixer-settler has excellent separation performances. The flow rate of organic feed solution is 3 mL/min and the flow ratio of feed solution (1BF) to aqueous back extraction stream (1BX) and to organic wash stream (1BS) is 4/1/1. For an organic feed of 84 g/L uranium and 1.40 ⁓ 2.64 g/L plutonium, both the separation factor of plutonium from uranium and that of uranium from plutonium are apparently higher than 104

IGF-1 Signaling is Essential for Differentiation of Mesenchymal Stem Cells for Peak Bone Mass

Survival of children with chronic medical illnesses is leading to an increase in secondary osteoporosis due to impaired peak bone mass (PBM). Insulin-like growth factor type 1 (IGF-1) levels correlate with the pattern of bone mass accrual and many chronic illnesses are associated with low IGF-1 levels. Reduced serum levels of IGF-1 minimally affect the integrity of the skeleton, whereas recent studies suggest that skeletal IGF-I regulates PBM. To determine the role of IGF-1 in postnatal bone mass accrual regardless of source, we established an inducible type 1 Igf receptor Cre/lox knockout mouse model, in which the type 1 Igf receptor was deleted inducibely in the mesenchymal stem cells (MSCs) from 3-7 weeks of age. The size of the mouse was not affected as knockout and wild type mice had similar body weights and nasoanal and femoral lengths. However, bone volume and trabecular bone thickness were decreased in the secondary spongiosa of female knockout mice relative to wild type controls, indicating that IGF-1 is critical for bone mass. IGF-1 signaling in MSCs in vitro has been implicated to be involved in both migration to the bone surface and differentiation into bone forming osteoblasts. To clarify the exact role of IGF-1 in bone, we found by immunohistochemical analysis that a similar number of Osterix-positive osteoprogenitors were on the bone perimeter, indicating migration of MSCs was not affected. Most importantly, 56% fewer osteocalcin-positive mature osteoblasts were present on the bone perimeter in the secondary spongiosa in knockout mice versus wild type littermates. These in vivo data demonstrate that the primary role of skeletal IGF-1 is for the terminal differentiation of osteoprogenitors, but refute the role of IGF-1 in MSC migration in vivo. Additionally, these findings confirm that impaired IGF-1 signaling in bone MSCs is sufficient to impair bone mass acquisition.

Parathyroid hormone induces differentiation of mesenchymal stromal/stem cells by enhancing bone morphogenetic protein signaling

Parathyroid hormone (PTH) stimulates bone remodeling and induces differentiation of bone marrow mesenchymal stromal/stem cells (MSCs) by orchestrating activities of local factors such as bone morphogenetic proteins (BMPs). The activity and specificity of different BMP ligands are controlled by various extracellular antagonists that prevent binding of BMPs to their receptors. Low-density lipoprotein receptor-related protein 6 (LRP6) has been shown to interact with both the PTH and BMP extracellular signaling pathways by forming a complex with parathyroid hormone 1 receptor (PTH1R) and sharing common antagonists with BMPs. We hypothesized that PTH-enhanced differentiation of MSCs into the osteoblast lineage through enhancement of BMP signaling occurs by modifying the extracellular antagonist network via LRP6. In vitro studies using multiple cell lines, including Sca-1(+) CD45(-) CD11b(-) MSCs, showed that a single injection of PTH enhanced phosphorylation of Smad1 and could also antagonize the inhibitory effect of noggin. PTH treatment induced endocytosis of a PTH1R/LRP6 complex and resulted in enhancement of phosphorylation of Smad1 that was abrogated by deletion of PTH1R, β-arrestin, or chlorpromazine. Deletion of LRP6 alone led to enhancement of pSmad1 levels that could not be further increased with PTH treatment. Finally, knockdown of LRP6 increased the exposure of endogenous cell-surface BMP receptor type II (BMPRII) significantly in C2C12 cells, and PTH treatment significantly enhanced cell-surface binding of (125) I-BMP2 in a dose- and time-dependent manner, implying that LRP6 organizes an extracellular network of BMP antagonists that prevent access of BMPs to BMP receptors. In vivo studies in C57BL/6J mice and of transplanted green fluorescent protein (GFP)-labeled Sca-1(+) CD45(-) CD11b(-) MSCs into the bone marrow cavity of Rag2(-/-) immunodeficient mice showed that PTH enhanced phosphorylation of Smad1 and increased commitment of MSCs to osteoblast lineage, respectively. These data demonstrate that PTH enhancement of MSC differentiation to the osteoblast lineage occurs through a PTH- and LRP6-dependent pathway by endocytosis of the PTH1R/LRp6 complex, allowing enhancement of BMP signaling.

E3 ubiquitin ligase Siah-1 facilitates poly-ubiquitylation and proteasomal degradation of the hepatitis B viral X protein

Hepatitis B viral X protein (HBx) is a multifunctional transactivator and implicated in hepatitis B virus (HBV) replication and hepatocarcinogenesis. HBx can be ubiquitinated and degraded through ubiquitin-proteasome pathway. However, the E3 ubiquitin ligase regulating HBx ubiquitin-dependent degradation is still unknown. In this study, we identified Siah-1 as a novel E3 ubiquitin ligase for HBx, which interacted with HBx and facilitated HBx poly-ubiquitylation and proteasomal degradation. Co-expression of Siah-1 attenuated the transcriptional transactivation of HBx on glucocorticoid response element (GRE), heat shock response element (HSE) and cAMP response element (CRE) signal pathways. Moreover, Siah-1 participated in p53-mediated HBx degradation. Therefore, Siah-1 may play important roles in ubiquitin-dependent degradation of HBx and may be involved in suppressing the progression of hepatocellular carcinoma (HCC).

Polymorphisms in the promoter regions of matrix metalloproteinases 1 and 3 and cancer risk: a meta-analysis of 50 case-control studies

Matrix metalloproteinase (MMP) 1 and MMP3 are enzymes that degrade the extracellular matrix and have been implicated to play an important role in cancer development. Many studies have been carried out on the association between polymorphisms of MMP1 -1607 1G>2G and MMP3 -1171 5A>6A and cancer risk. However, results from these studies remain inconclusive. Here, we performed a meta-analysis of >38 000 subjects to better assess the purported associations. For MMP1, -1607 2G/2G genotype carriers were found to have an increased risk of colorectal cancer [2G/2G versus 2G/1G + 1G/1G, odds ratio (OR) = 1.48, 95% confidence interval (CI) (1.26-1.74), P(heterogeneity) = 0.066, I(2) = 49.3%], head and neck cancer [2G/2G versus 2G/1G + 1G/1G, OR = 1.61, 95% CI (1.26-2.07), P(heterogeneity) = 0.002, I(2) = 64.7%] and renal cancer [2G/2G versus 2G/1G + 1G/1G, OR = 1.82, 95% CI (1.38-2.39), P(heterogeneity) = 0.589, I(2) = 0.0%] risk. For MMP3, no association was found between -1171 5A>6A polymorphism and cancer risk in the overall group [6A versus 5A, OR = 1.00, 95% CI (0.95-1.05), P(heterogeneity) = 0.124, I(2) = 24.9%] and individual cancer subgroups, but stratified analysis by smoking status showed that this polymorphism had different effects on smokers and non-smokers under recessive genetic model. In summary, our study suggests that MMP1 -1607 2G may be associated with an increased cancer risk for certain types of cancers, MMP3 -1171 5A>6A may not be a major risk factor for cancer, but it may be modified by certain environmental factors. Future studies with larger sample sizes are warranted to further evaluate these associations in more detail.

Isolation and partial characterization of novel genes encoding acidic cellulases from metagenomes of buffalo rumens

AIMS

To clone and characterize genes encoding novel cellulases from metagenomes of buffalo rumens.

METHODS AND RESULTS

A ruminal metagenomic library was constructed and functionally screened for cellulase activities and 61 independent clones expressing cellulase activities were isolated. Subcloning and sequencing of 13 positive clones expressing endoglucanase and MUCase activities identified 14 cellulase genes. Two clones carried two gene clusters that may be involved in the degradation of polysaccharide nutrients. Thirteen recombinant cellulases were partially characterized. They showed diverse optimal pH from 4 to 7. Seven cellulases were most active under acidic conditions with optimal pH of 5.5 or lower. Furthermore, one novel cellulase gene, C67-1, was overexpressed in Escherichia coli, and the purified recombinant enzyme showed optimal activity at pH 4.5 and stability in a broad pH range from pH 3.5 to 10.5. Its enzyme activity was stimulated by dl-dithiothreitol.

CONCLUSIONS

The cellulases cloned in this work may play important roles in the degradation of celluloses in the variable and low pH environment in buffalo rumen.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provided evidence for the diversity and function of cellulases in the rumen. The cloned cellulases may at one point of time offer potential industrial applications.

[Construction of subtractive cDNA library of apoptosis-related genes in NB4 cells treated by arsenic trioxide]

OBJECTIVE

Construct the gene library of apoptosis related genes in acute promyelocytic leukemia (APL) cell line NB4 cells treated by arsenic trioxide to clarify the apoptotic mechanism of NB4 cells.

METHOD

APL cell line NB4 cells treated with or without arsenic trioxide for 24 hours. Total RNA was extracted and suppress subtractive hybridization (SSH) was conducted according to the manual. With the cDNA of the apoptosis cells as the tester and that of control cells as the driver, forward and reverse hybridization was performed. Differentially expressed genes were linked with pGEM-Teasy cloning vector and transformed into E. coli DH5alpha. The positive clones were screened by blue and white spot. PCR were used to amplify these genes.

RESULT

The subtractive cDNA libraries related with apoptosis of NB4 cells were successfully constructed.

CONCLUSION

The constructed subtractive libraries are suitable for further study on the functional genes associated with apoptosis ofNB4 cells induced by arsenic trioxide.

[Rapid detection of anti-HAV IgM by solid-phase immunosorbent hemagglutination inhibition test]

A solid-phase immunosorbent hemagglutination inhibition test (SPISHAI) was developed for hepatitis A virus-specific immunoglobulin M (IgM) antibody. Three hundred thirty and six sera were comparatively detected with both SPISHAI and ELISA. Among them 97 sera were positive and 237 were negative with both method. The crude agreement rate was 99.4%. With SPISHAI the titers of anti-HAV IgM ranged from 1:20 to 1:327,680 among tested sera from infected individuals by HAV. The specificity of SPISHAI was confirmed by 2-ME treatment method and blocking test. The patients with non-A hepatitis all got negative results. The SPISHAI does not require conjugated antibody and sophisticated equipment, and is not interfered with rheumatoid factor in sera. Furthermore, the result of the test can be got within 3 hours. Therefore, the SPISHAI is a cheap and simple, and could be applied for early diagnosis and epidemiological surveillance of hepatitis A in the community and in primary health care.

[Observation of the outcome of 112 cases with Graves' disease treated by short-term antithyroid drug therapy for one year]

One hundred and twelve new cases with Graves' disease were treated by tapazole for 6 months and followed-up for another 12 months in a prospective study. One hundred and eleven cases completed the whole course of study, and only one failed to be followed up. The results of the follow-up for 12 mon showed that the remission rate was 41.4% (46/111) and relapse rate was 58.6% (65/111). The present study indicated that the remission or relapse was related with serum levels of T3 before treatment, shrank goiter and disappearance of goiter bruit during the treatment as well as thyroid suppression rate, but not related to sex, age, period of illness before therapy or severity of the disease. It is suggested that a 6-mon antithyroid drug therapy instead of traditional long term therapy may be suitable for those patients who are with a reduced goiter and disappeared goiter bruit during the antithyroid therapy, and suppressible thyroid up-take by T3 and whose serum levels of T3 before treatment are not very high. So the patients may benefit from the short-term therapy. They are not only able to obtain a prolonged remission but also save time and money.