White matter tracts that overlap with the thalamus and the putamen are protected against multiple sclerosis pathology

BACKGROUND

The thalamus and the putamen are highly connected hubs implicated in multiple sclerosis (MS) pathology. It remains unclear if white matter (WM) tracts, which pass through them, have a different susceptibility to MS pathology, and if so, if their impact on disability predominates over that exerted by disease in other WM tracts. We hypothesized that WM tracts connected to and passing through these hubs (subsequently termed hub+ tracts) would be more susceptible to MS-related pathology than tracts that do not pass through them (hub- tracts) due to retrograde and anterograde distant degeneration. Thus, we compared the lesion load and neurite orientation dispersion and density imaging (NODDI) derived metrics between hub+ and hub- tracts and assessed the relationship between these MRI metrics and those of physical impairment.

METHODS

Eighteen patients (mean age of 45.5 years, 12 females) had 3 Tesla MRI consisting of T1-weighted and T2-weighted Fluid Attenuated Inversion Recovery (FLAIR), and NODDI from which the orientation dispersion index (ODI), neurite density index (NDI), and isotropic volume fraction (IVF) were derived. Forty-nine WM tracts, i.e., 12 hub+ and 37 hub- tracts, were segmented out. Exploratory analyses of the differences in lesion burden, whole tract and normal appearing WM (NAWM) NODDI metrics were carried out between the two types of tracts using a Mann-Whitney U test. Correlations with physical impairment, quantified using the expanded disability status scale (EDSS) and timed 25-foot walk (T25FW) test were assessed using Spearman correlation analyses.

RESULTS

Hub- tracts had larger T1- (p<0.001) and T2-lesion (p<0.001) volumes; lower ODI (p<0.001), NDI (p<0.001) and higher IVF (p = 0.020) in comparison to hub+ tracts. Measures of tissue injury in hub+ tracts correlated with those of clinical disability, though less strongly than in hub- tracts.

CONCLUSIONS

Contrary to our hypothesis, our exploratory pilot study results suggest that WM tracts that overlap with the thalamus and the putamen have a lower degree of lesional and non-lesional tissue injury, suggesting a protective role of the hubs against MS pathology or a higher degree of vulnerability of those not passing through hub stations. We also show a weaker association between disability impairment and hub+ pathology, compared to that in hub- tracts. Our findings point to a potential role of disease location in relation to hubs as guidance for treatment personalization in MS.

The Effect of Body Mass Index on Initial Breast Cancer Stage Among Korean Women

BACKGROUND

The relationship between obesity and breast cancer stage is not well-known in the Korean population. This study aimed to identify the effect of body mass index (BMI) on initial breast cancer stage.

PATIENTS AND METHODS

Among patients who underwent surgery for breast cancer (stages 0-III) from June 2003 to December 2018, we analyzed 4510 patients for whom there were BMI data.

RESULTS

The average BMI of our patients was 23.5 (14.2-44.9). In total, 4.6% and 24.2% of the patients had a BMI of ≥30 and 25-29.9, respectively. In the patients with obesity, the proportion of T2 to T4 was 41.4%, which was higher than that in patients with a BMI of 25 to 29 (28.4%; P = .001) or a BMI of <25 (23.3%; P < .001). There was no difference in positive rates of estrogen receptor and progesterone receptor with BMI, but obese patients were less likely to be human epidermal growth factor receptor 2 positive. Patients with higher stages were more likely to have a higher BMI. The effect of BMI on stage was stronger in patients <50 years (odds ratio, 2.439; 95% CI, 1.783-3.335). Although there was no statistical significance, tumors >2 cm were less likely to be palpable in obese patients than in patients of normal weight (nonpalpable in 33.8% and 27.0%, respectively).

CONCLUSION

Our study suggests that obesity is associated with a more advanced breast cancer stage, which represents a poor prognosis, and large tumors tend to be less palpable in women with obesity.

Abstract P2-07-04: A novel diagnostic androgen receptor gene signature links clinical outcomes and preclinical response to enzalutamide, paclitaxel or the combination in triple-negative breast cancer

Background: The androgen receptor (AR) is expressed in ≈70% of all breast cancers (BCs) and may be necessary for proliferation and survival advantage in AR+ tumors. A novel gene signature associated with AR-signaling biology (PREDICT AR) was developed by sequencing triple-negative BC (TNBC) tumors collected in a phase 2 study evaluating enzalutamide (ENZA) monotherapy1; clinical outcomes were superior in patients (pts) with PREDICT AR+ vs PREDICT AR- tumors.1,2 ENZA blocks nuclear localization and suppresses its activity.3 Paclitaxel (PTX) stabilizes microtubules and may also block AR nuclear localization. Thus we hypothesize that response to PTX-based therapy may be additive in PREDICT AR+ vs PREDICT AR- disease. This study sought to identify independent clinical datasets with PREDICT AR+ gene signature to assess outcomes following PTX-based therapy. Preclinically, we investigated the antitumor activity of ENZA, PTX, or ENZA+PTX in AR-driven TNBC models.

Methods: We probed publicly available TNBC clinical databases from Gene Expression Omnibus datasets to assess PREDICT AR status and clinical outcomes. Similarly, we assessed 21 TNBC lines for PREDICT AR status. BT549, MDA-MB-436, and MDA-MB-453 were treated with ENZA, PTX, or ENZA+PTX to determine activity. Cell signaling and pathway activation were assessed by western blot. ENZA and PTX activity was assessed in PREDICT AR+ xenograft models. Tumor RNA sequencing and immunohistochemistry were used to identify gene signatures, potentially predictive biomarkers, and potential synergistic effects of ENZA+PTX.

Results: The prevalence of PREDICT AR+ tumors in one cohort of 182 pts with primary TNBC4 was 51%. Distant relapse-free survival following PTX-based adjuvant/neoadjuvant therapy was not statistically different between pts with PREDICT AR+ vs PREDICT AR- TNBC (p=0.605). Pathologic complete response rates were 12.5% for PREDICT AR+ vs 21.0% for PREDICT AR- TNBC. Additional sets of pts with primary TNBC are being evaluated. Preclinically, we observed a dose-dependent inhibition of cell viability with either ENZA or PTX in AR+ TNBC cell lines and additive effects from ENZA+PTX. In PREDICT AR+ xenograft models, ENZA or PTX treatment resulted in a dose-dependent antitumor response. Combination studies are underway. Tumor RNA sequencing are being evaluated for gene signature of synergistic antitumor response to ENZA+PTX.

Conclusion: Analyzing publicly available clinical datasets, we found that PREDICT AR+ status was not associated with differential outcomes following PTX-based therapy in primary TNBC, suggesting there is potential to provide additive benefits in PTX-based therapy with ENZA. In preclinical studies, we observed additive effects when combining ENZA+PTX in PREDICT AR+ TNBC lines compared with single agent treatments. Taken together, these data suggest ENZA combined with PTX might provide additive benefits in a clinical setting for pts with PREDICT AR+ TNBC.

References

1. Traina TA et al. J Clin Oncol 2015:33(suppl):abstr 1003.

2. Parker J et al. J Clin Oncol 2015;33(suppl):abstr 1083.

3. Tran C et al. Science 2009;324:787-90.

4. Hatzis C et al. JAMA 2011;305:1873-81.

Citation Format: Phan VT, Protter AA, Peterson AC, Parker JS, Yoon K, Tudor IC, Paton V, Noonberg S, Uppal H. A novel diagnostic androgen receptor gene signature links clinical outcomes and preclinical response to enzalutamide, paclitaxel or the combination in triple-negative breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-07-04.

Differential gene expression in laboratory strains of human head and body lice when challenged with Bartonella quintana, a pathogenic bacterium

Human head and body lice are obligatory hematophagous ectoparasites that belong to a single species, Pediculus humanus. Only body lice, however, are vectors of the infectious Gram-negative bacterium Bartonella quintana. Because of their near identical genomes, yet differential vector competence, head and body lice provide a unique model system to study the gain or loss of vector competence. Using our in vitro louse-rearing system, we infected head and body lice with blood containing B. quintana in order to detect both differences in the proliferation of B. quintana and transcriptional differences of immune-related genes in the lice. B. quintana proliferated rapidly in body lice at 6 days post-infection, but plateaued in head lice at 4 days post-infection. RNAseq and quantitative real-time PCR validation analyses determined gene expression differences. Eight immunoresponse genes were observed to be significantly different with many associated with the Toll pathway: Fibrinogen-like protein, Spaetzle, Defensin 1, Serpin, Scavenger receptor A and Apolipoporhrin 2. Our findings support the hypothesis that body lice, unlike head lice, fight infection from B. quintana only at the later stages of its proliferation.

Abstract P1-05-18: Determining the molecular mechanism of the breast cancer-induced brain metastasis and a role of a novel pan-TGF-β inhibitor as a potential therapy for brain metastasis in a mouse xenograft model

Breast cancer (BCa) is the most common malignant disease in women in the U.S. Nearly 20% of patients with advanced BCa are eventually diagnosed with brain lesions, which is a devastating complication in patients with BCa over-expressing EGF receptor family members including Her2 positive and triple negative breast cancer. It is the most feared complication of BCa in part because are not capable of significantly treating the BCa-induced brain metastases due to the inability of the available treatment regimens to effectively penetrate the blood brain barrier (BBB) and also due to our limited knowledge on cellular and molecular mechanisms that drive the homing to and growth in the brain of BCa cells. Therefore, there is a need of efficient model system that can significantly contribute towards our understanding of different factors from both host and tumor leading to brain metastasis. We have recently isolated a novel BCa cell line B6TC that was generated through fusion between human BCa, MDA-MB-231 and ZR-75-1 cells in mouse bone marrow. This B6TC cell line showed higher propensity to metastasize to brain than its parental cells when inoculated through intracardiac injection in female athymic nude mice. In order to generate a highly brain metastatic breast cancer model for mechanistic research, we subjected the B6TC cells through four rounds of selection for cells that were capable of trans-endothelial cell invasion to obtain cells that could invade through BBB. This in vitro selected cell line was further subjected through three rounds of in vivo selection for cells that were capable of metastasizing to the brain and the cells after third round selection was named N3LR, which has the highest potential to cause brain metastasis. In searching for genes and pathways that may contribute to the increased brain metastasis of N3-LR cell with microarray analysis, we found that the transforming growth factor-beta (TGFβ) signaling pathway is upregulated in N3-LR cell in comparison with B6TC cell, in addition to the EGF and prostaglandin signaling pathways that have been reported to be associated with brain metastatic breast cancer cells. Functional comparison also showed that N3-LR cell was more migratory than B6TC cell and more responsive to TGFβ-induced phosphorylation of Smad3 as well as migration, suggesting that TGFβ signaling may contribute to the increased brain metastatic potential. We next investigated whether metastatic tumor growth in the brain microenvironment can be inhibited by systemic administration of a potent pan-TGFβ inhibitor, BGERII- a recombinant fusion protein containing the endoglin domain of betaglycan (BGE) and the extracellular domain of RII. The animals were inoculated intracardically with N3LR, the most potent subline of highly metastatic B6TC cells, and were then treated with vehicle or BGERII systemically via i.p. injection right after the inoculation. After three weeks, the BGERII treated group showed lower brain metastasis incidence and tumor burden as detected by whole mouse bioluminescence and GFP imaging. Further analyses to understand the underlying molecular and regulatory mechanism of brain metastasis and its intervention in our mouse model is underway for the discovery of novel molecularly targeted drugs to prevent and eradicate BCa metastasis initiation, progression and recurrence.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-05-18.

CHK2 kinase promotes pre-mRNA splicing via phosphorylating CDK11(p110)

Checkpoint kinase 2 (CHK2) kinase is a key mediator in many cellular responses to genotoxic stresses, including ionizing radiation (IR) and topoisomerase inhibitors. Upon IR, CHK2 is activated by ataxia telangiectasia mutated kinase and regulates the S-phase and G1-S checkpoints, apoptosis and DNA repair by phosphorylating downstream target proteins, such as p53 and Brca1. In addition, CHK2 is thought to be a multi-organ cancer susceptibility gene. In this study, we used a tandem affinity purification strategy to identify proteins that interact with CHK2 kinase. Cyclin-dependent kinase 11 (CDK11)(p110) kinase, implicated in pre-mRNA splicing and transcription, was identified as a CHK2-interacting protein. CHK2 kinase phosphorylated CDK11(p110) on serine 737 in vitro. Unexpectedly, CHK2 kinase constitutively phosphorylated CDK11(p110) in a DNA damage-independent manner. At a molecular level, CDK11(p110) phosphorylation was required for homodimerization without affecting its kinase activity. Overexpression of CHK2 promoted pre-mRNA splicing. Conversely, CHK2 depletion decreased endogenous splicing activity. Mutation of the phosphorylation site in CDK11(p110) to alanine abrogated its splicing-activating activity. These results provide the first evidence that CHK2 kinase promotes pre-mRNA splicing via phosphorylating CDK11(p110).

Assessment of follow-up sonography and clinical improvement among infants with congenital muscular torticollis

BACKGROUND AND PURPOSE

Infants grow rapidly, which causes the SCM to thicken physiologically. Therefore some cases of physiologically-thickened SCM can be confused with a poor response to physical therapy. There have been only a few quantitative ultrasonographic studies on the clinical outcome of rehabilitation for CMT. Our aim was to evaluate whether a new sonographic assessment method that uses the muscular thickness ratio of the SCM can help quantify the outcome of rehabilitation therapy for patients with CMT.

MATERIALS AND METHODS

We evaluated 48 patients (male/female, 17:31; mean age, 3.9 months) who were diagnosed with CMT and who underwent initial and follow-up sonography. The ratio of the thickness of the involved SCM to the thickness of the intact SCM (SCM thickness ratio) was calculated. A scoring system based on the range of motion of the neck was used to assess clinical improvement. The correlations between clinical improvement and the thickness of the involved muscle, the difference in involved muscle thickness, the SCM thickness ratio, and the difference in the SCM thickness ratio were evaluated with Spearman rank correlations.

RESULTS

Follow-up Cheng scores were higher than initial scores; this difference indicates clinical resolution (follow-up, 4.90; initial, 3.38). The SCM thickness ratio at follow-up was lower than that at the initial evaluation (follow-up, 1.29-1.34; initial, 1.65-1.77). Intra- and interobserver agreements were excellent. Most variables were moderately correlated with clinical improvement (correlation coefficients, 0.36-0.509). R1 showed the highest correlation with clinical improvement (0.481 and 0.509), followed by the initial maximal thickness of the SCM (0.434 and 0.488). ΔP (P1-P2) and ΔR showed similar correlation coefficients with clinical improvement.

CONCLUSIONS

Measurement of the SCM thickness ratio appears to overcome the problem of a false-positive diagnosis of clinical aggravation of CMT resulting from physiologic growth. R1 and ΔR are accurate objective measurements, which can be used in the management of CMT.

P2-01-12: Determining the Molecular Signature That Drives Breast Cancer-Induced Brain Metastasis in a Mouse Xenograft Model

Breast cancer (BCa) is the most common malignant disease in women in U.S. and the mortality in BCa patients is due to the metastasis of the disease from primary site. Brain metastasis accounts for nearly 20% of all metastases in BCa. It is the most feared complication of BCa because of very few effective treatment regimens available, leading to lower survival rate in patients. The exact molecular mechanism for metastases of BCa into brain is unknown. Rodent model systems have been reported for brain metastasis in BCa but the current models for brain metastasis have limitations. Therefore, there is a need of efficient model system that can significantly contribute towards our understanding of different factors from both host and tumor leading to brain metastasis.

Previously we reported isolation and characterization of estrogen independent B6TC cells that are derived from the stable spontaneous fusion of MDA-MB-231/GFP/Neo and ZR-75-1/GFP/puro in mouse bone marrow microenvironment. This chimeric B6TC has propensity to metastasize to brain when inoculated through intracardiac (I.C.) route, and express stem cell-like features. In the present study using B6TC, we have developed an efficient and novel mouse model for studying BCa-induced brain metastasis. We have generated three cell lines from B6TC through three successive rounds of inoculation in mouse and subsequent isolation of brain metastatic cells. Each round of selection enhanced the brain metastatic propensity. An initial microarray analysis identified genes like MMP1, HB-EGF, ST3GAL1, PTGS2, ITGA3, and CXCR4, which showed significant up-regulation in B6TC compared to its parental metastatic MDA-MB-231 or nonaggressive ZR-75-1 cells. These genes are implicated in metastasis regulation. A second round of RNA microarray was performed with three sublines of B6TC with successively enhanced brain metastatic propensity to identify unique potential brain metastatic genes showing gradual up or down-regulation over generations. From analysis of the gene expression profiles, apart from potent brain metastatic genes detected earlier, we also identified some molecular pathways, including TGF beta signaling pathway that are associated with enhanced brain metastasis. The B6TC model is novel for studying the molecular mechanism of brain metastasis, as in this model, apart from experimental metastasis in brain through I.C route, cells show spontaneous metastases to the brain from the primary tumor and this unique feature will enable us to study the mechanisms of the early steps of brain metastasis progression. Further analyses to find out common miRNAs that are over or under-expressed in the sublines over successive generations and determination of gene targets of miRNA are underway. This study will not only provide valuable insight into molecular mechanism of BCa-induced brain metastasis but also lay the foundation to identify novel prognostic and therapeutic markers of brain metastases, leading ultimately to the discovery of novel molecularly targeted drugs to prevent and eradicate BCa metastasis initiation, progression and recurrence.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-01-12.

Development of murine leukemia virus-based retroviral vectors with a minimum possibility of cis-activation

The possibility of insertional mutagenesis in retroviral gene therapy can be reduced by using a vector lacking the enhancer sequence present in the U3 of the long-terminal repeats. However, such vectors suffer from many pitfalls. We attempted to improve a murine leukemia virus-based retroviral vector containing the enhancer-free U3, first by making it easier to construct a producer line and then by introducing the cellular RPL10 promoter as an internal promoter. The reverse orientation of the expression cassette of the transgene was found to give higher transducing titer and higher-level gene expression. The deletion analysis revealed that the 54-bp-long sequence of U3 (34 and 20 bp present at 5' and 3' extreme ends, respectively) was sufficient for the functions of retroviral vectors. The data from the in vitro cell culture assay indicated that the final construct, ROK, containing all these features, had little cis-activation activity, even if it was placed right upstream from the RNA start site of the neighboring gene. Our data suggested that the newly developed vector might provide increased safety, while still producing high viral titer from a stable producer line and high-level gene expression in various target cells including human CD34(+) stem cells.

C/EBPalpha expression is partially regulated by C/EBPbeta in response to DNA damage and C/EBPalpha-deficient fibroblasts display an impaired G1 checkpoint

We observed that C/EBPα is highly inducible in primary fibroblasts by DNA damaging agents that induce strand breaks, alkylate and crosslink DNA as well as those that produce bulky DNA lesions. Fibroblasts deficient in C/EBPα (C/EBPα^-/-) display an impaired G₁ checkpoint as evidenced by inappropriate entry into S-phase in response to DNA damage and these cells also display an enhanced G₁ to S transition in response to mitogens. The induction of C/EBPα by DNA damage in fibroblasts does not require p53. EMSA analysis of nuclear extracts prepared from UVB- and MNNG-treated fibroblasts revealed increased binding of C/EBPβ to a C/EBP consensus sequence and ChIP analysis revealed increased C/EBPβ binding to the C/EBPα promoter. To determine whether C/EBPβ has a role in the regulation of C/EBPα we treated C/EBPβ^-/- fibroblasts with UVB or MNNG. We observed C/EBPα induction was impaired in both UVB- and MNNG- treated C/EBPβ^-/- fibroblasts. Our study reveals a novel role for C/EBPβ in the regulation of C/EBPα in response to DNA damage and provides definitive genetic evidence that C/EBPα has a critical role in the DNA damage G₁ checkpoint.

Diversity of the osteoblastic phenotype

Studies of bone cells in culture have raised two salient questions: are the findings representative of the in vivo situation and can the conflicting data from different cell models be reconciled? Review of the literature indicates that all osteoblastic cells, defined by their origin or by their ability to produce mineralized matrix, have a few common properties: production of type I collagen; increased alkaline phosphatase activity; and parathyroid hormone-stimulated adenylate cyclase. Other features, such as osteocalcin and prostaglandin E production and the response to prostaglandin E, are selectively expressed by certain cell types. Pilot studies on mRNA levels of 'bone proteins' in developing calvaria suggest that such differences may reflect stages in osteoblastic differentiation. Immortalization of calvaria-derived cells using a SV40 large T antigen vector, which may freeze the cells in their particular state of differentiation (as proposed for leukaemia cells), yields phenotypes consistent with that hypothesis. Immortal cell lines may thus help to characterize osteoblastic differentiation. The diversity of osteoblast responses in culture to hormones and growth factors could be due to these phenotype differences but could also represent a subspecialization of differentiated cells. In addition, in the organism regulatory agents act in concert on a heterogeneous interactive cell population. Nonetheless cell cultures can be useful in screening for and predicting in vivo responses, as was shown by the 1,25-(OH)2D3 stimulation of osteocalcin, and for studying the molecular mechanisms of regulatory effects. Cell lines are also convenient for the production of specific proteins and cDNA libraries, and for the expression of specific genes.

The nuclear expressions of ERK1/2 and p38 can be useful markers for tumor invasiveness and lymph node metastasis in stomach cancer

15109

Background: Extracellular-regulated kinases (ERKs) were shown to have a function in cellular proliferation or differentiation and p38 were known as to be involved in apoptotic processes in tumor development. Tissue inhibitors of metalloproteinase(TIMP) have been known to be a important role in tumor cell invasion, which was postulated to be regulated by ERKs and p38. The clinical implication of ERKs and p38 on stomach cancer was investigated Methods: By immunohistochemistry with an antibody specific for dually phosphorylated ERK 1 /2 and 2 , TIMP-1 and -2, and p38 on formaline-fixed paraffin-embedded tissue, we have examined 57 primary stomach cancer consisting of 36 cases of intestinal type and 21 cases of diffuse type carcinomas. One-way ANOV(non-parametric) was used to compare differences among more three groups and paired T-test were used between groups.P<0.05 was considered as statistic significant. Results: The expression rate of ERK1/2 in the nuclei of the tumor cells was 21.5%, The expressions of ERK 2, TIMP-1 TIMP-2, were 56.4%, 50.9%, 61.4%. The expression rate of p38 in the tumor cells was 37.7%.. The p38 expression had significant correlation with invasion depth of tumor(p=0.016), lymph node metastasis(p=0.030), and TIMP-2 expression(p=0.038). ERK1/2 had significant association with tumor invasion(p=0.003), lymph node metastasis(p-0.013), tumor cell grades(p=0.030), and TIMP-1(p=0.029). ERK-2, TIMP-1 and 2 had no significant relationship to tumor invasion and metastasis Conclusions: These results suggest that the nuclear expressions of ERK1/2 and p38 can be the useful markers predicting the progression of stomach cancer towards invasiveness and metastasis

No significant financial relationships to disclose.

Decreased survival of C/EBP beta-deficient keratinocytes is due to aberrant regulation of p53 levels and function

Recent studies have identified roles for C/EBPbeta in cellular survival and tumorigenesis, however, the mechanisms through which C/EBPbeta regulates these processes are not fully understood. Previously, we demonstrated that C/EBPbeta(-/-) mice are resistant to carcinogen-induced skin tumorigenesis and in response to topical carcinogen treatment display a 17-fold increase in keratinocyte apoptosis compared to wild-type mice. Here, we have investigated the mechanisms through which C/EBPbeta regulates apoptosis in response to carcinogenic stress. Analysis of carcinogen-treated C/EBPbeta(-/-) mouse skin revealed a striking increase in the number of p53 immunopositive keratinocytes in the epidermis of C/EBPbeta(-/-) mice compared to wild-type mice and this increase was temporally associated with a concomitant anomalous increase in apoptosis. The increased levels of p53 were functional as Mdm2, Bcl-2, C/EBPalpha and p21 were differentially regulated in the epidermis of carcinogen-treated C/EBPbeta(-/-) mice. The increase in p53 protein was not associated with an increase in p53 mRNA levels. To determine whether p53 is required for the increased apoptosis in C/EBPbeta(-/-) mice, C/EBPbeta/p53 compound knockout mice were generated. Carcinogen-treated C/EBPbeta/p53 compound knockout mice did not display increased apoptosis demonstrating p53 is required for the proapoptotic phenotype in C/EBPbeta(-/-) mice. Our results demonstrate that altered keratinocyte survival in C/EBPbeta(-/-) mice results from aberrant regulation of p53 protein and function and indicate C/EBPbeta has a role in the negative regulation of p53 protein levels in response to carcinogen-induced stress.

Differential cellular responses to exogenous DNA in mammalian cells and its effect on oligonucleotide-directed gene modification

Transient transfection has been widely used in many biological applications including gene regulation and DNA repair, but, so far, little attention has been paid to cellular responses induced by the transfected DNA. Here, we report that double-stranded (ds) DNA introduced into mammalian cells induced expression of a variety of genes involved in DNA damage signaling and DNA repair. The expression profile of the induced genes was highly dependent on the cell type, suggesting interactions between exogenous dsDNA and cellular proteins. Moreover, each cell line elicited a markedly different level of intrinsic cellular responses to the introduced dsDNA. Furthermore, the presence of single-stranded oligonucleotides or short duplexes consisting of two complementary oligonucleotides did not affect cellular response, indicating that the induction was highly dependent on the structure and length of exogenous DNA. The extent of induction of DNA damage, signaling and DNA repair activities correlated to episomal and chromosomal gene correction frequencies. In addition, the presented data indicate that the presence of exogenous dsDNA triggered a DNA damage response by activation of ATR (ataxia telangiectasia-Rad3-related) but not ATM (ataxia telangiectasia mutated) pathway.

In vivo alteration of the keratin 17 gene in hair follicles by oligonucleotide-directed gene targeting

Using intradermal injection of a chimeric RNA-DNA oligonucleotide (RDO) or a single-stranded oligonucleotide (ssODN) into murine skin, we attempted to make a dominant mutation (R94p) in the conserve alpha-helical domain of keratin 17 (K17), the same mutation found in pachyononychia congenichia type 2 (PC-2) patients with phenotypes ranging from twisted hair and multiple pilosebaceous cysts. Both K17A-RDO and -ssODN contained a single base mismatch (CGC to CCC) to alter the normal K17 sequence to cause an amino acid substitution (R94P). The complexes consisting of oligonucleotides and cationic liposomes were injected to C57B1/6 murine skin at 2 and 5 day after birth. Histological examination of skin biopsies at postnatal day 8 from several mice showed consistent twisted hair shafts or broken hair follicles at the sebaceous gland level and occasional rupture of the hair bulb or epidermal cyst-like changes. In the injected area, the number of full anagen hair follicles decrease by 50%. Injection of the control oligonucleotide, identical to K17A-RDO but containing no mismatch to the normal sequence, did not result in any detectable abnormality. The frequency of gene alteration was lower than 3%, according to the restriction fragment length polymorphism (RFLP) analysis of the genomic DNA isolated by dissection of hair follicles from slides. Although intradermal injection of K17A-RDO or K17-ssODN caused a dominant mutation in K17 affecting hair growth and morphology, these phenotypic changes were transient either due to the compensation of K17 by other keratins or the replacement of the mutated cells by normal surrounding cells during hair growth.

An unusual cause of hyperinsulinaemic hypoglycaemia syndrome

Endogenous hyperinsulinism as a cause for hypoglycaemia can be attributed to a number of different causes including insulinoma, sulphonylurea drugs and the newly described disorder non-insulinoma pancreatogenous hypoglycaemia (NIPH). The calcium stimulation test is increasingly used as a method for not only localizing insulinoma but also for distinguishing the above entities. We describe a case in which felonious sulphonylurea administration was used to mimic either an insulinoma or NIPH. Importantly, this case demonstrates that, contrary to previous reports, the insulin response to calcium stimulation in such cases may be uniformly positive and should alert the physician to possible surreptitious sulphonylurea ingestion.

Inhibitory effects of N-(substituted benzoylamino)-4-ethyl-1,2,3,6-tetrahydropyridines on nitric oxide generation in stimulated raw 264.7 macrophages

There has been great interest in reactive nitrogen intermediates and nitric oxide production in macrophages, particularly because of their contributory role in several pathophysiological conditions during acute and chronic inflammation. Several N-(substituted benzoylamino)-4-ethyl-1,2,3,6-tetrahydropyridines were previously synthesized as potential antiinflammatory agents. In the present study, the effects of four previously synthesized tetrahydropyridines (THPs) on cyclooxygenase (COX)-1 and COX-2 were screened and the effects of these compounds on lipopolysaccharide (LPS)-induced (2 micrograms/ml) nitric oxide and inducible nitric oxide synthase (iNOS) activity in RAW 264.7 macrophages were examined. 4-Bromo THP showed 9.4 microM of IC50 as the most potent derivative among the tested THPs followed by 4-nbuthyl, 4-fuoro, and 4-methyl THP with IC50 values of 30.9, 38.9 and 80.3 microM, respectively (indomethacin IC50 = 53.8 microM). None of the tested compounds showed cytotoxic effects to the RAW 264.7 macrophages. All of the tested THPs exhibited COX-1 and COX-2 nonselective inhibition. These results suggest that previously synthesized THP derivatives may have dual effects through inhibiting both COX and nitric oxide by inhibiting iNOS.

Oligonucleotide-directed single-base DNA alterations in mouse embryonic stem cells

We have investigated the use of single-stranded oligodeoxy-nucleotides (ssODN) to produce specific single-base alterations in episomal and chromosomal DNA in mouse embryonic stem (ES) cells. Two different reporter genes, EGFP and LacZ, each with a single point mutation that inactivates reporter activity, were used. ssODN homologous to the target sequence, except for a single mismatch at the mutant base, were used to correct the mutant reporter genes. When tested in CHO-K1 cells, the ssODN showed correction rates of 0.5-1.0%, consistent with prior reports. ssODN in the antisense orientation provided higher rates of gene conversion than those in the sense orientation for both reporter genes. Nuclear extracts from mouse ES cells exhibited nearly the same correction activity as extracts from CHO-K1 cells. ssODN corrected the mutant bases of both episomal and chromosomal mutant reporter genes in mouse ES cells. Although the efficiency of gene correction observed in ES cells is low, approximately 10(-4), these results demonstrate that ssODN can produce single-base alterations in the genomic DNA of mouse ES cells. As conversion efficiency is improved by the continued development of oligonucleotide structure and DNA delivery methods, ssODN could be used to produce ES cells with specific mutations in any gene in a single step. The targeted ES cells could in turn be used to create accurate mouse models of inherited diseases.

Simultaneous targeted alteration of the tyrosinase and c-kit genes by single-stranded oligonucleotides

We have shown that various forms of oligonucleotides, chimeric RNA-DNA oligonucleotide (RDO) and single-stranded oligodeoxynucleotide (ODN), are capable of chromosomal gene alterations in mammalian cells. Using two ODNs we corrected an inactivating mutation in the tyrosinase gene and introduced an activating mutation into the c-kit gene in a single albino mouse melanocyte. Relying on a pigmentation change caused by tyrosinase gene correction, we determined the frequency of gene targeting events ranging from 2 x 10(-4) to 1 x 10(-3), which is comparable to our previously published data using RDO. However, ODN showed more reproducible gene correction than RDO and produced pigmented cells among 60% of experiments, in comparison with 10% by RDO. DNA sequence analysis of the converted cells revealed that two out of eight individual pigmented clones harbored the mutated c-kit gene. Targeted modification of both genes resulted in the ability of the tyrosinase to convert tyrosine to melanin, and in the constitutive activation of the Kit receptor kinase. Thus, for the first time, we demonstrate the feasibility of simultaneous targeting of two genes in a single cell and show that a selection strategy to identify cells that have undergone a gene modification can enrich the targeted cells with the desired gene alteration.

Multilineage differentiation of adult human bone marrow progenitor cells transduced with human papilloma virus type 16 E6/E7 genes

We have established a new adult human bone marrow-derived cell line hMPC 32F, stably transduced with human papilloma virus type 16 E6/E7 genes, that displays mesenchymal multilineage differentiation ability in vitro. The hMPC 32F cells exhibited a population doubling time of 22 h and have been maintained in culture for about 20 passages. When cultured in conditions promoting osteogenic, adipogenic, or chondrogenic differentiation, hMPC 32F cells expressed mature differentiated phenotypes. These include (1) osteoblastic phenotype characterized by upregulated alkaline phosphatase (ALP) expression and extracellular matrix mineralization, (2) adipocytic phenotype with the presence of intracellular lipid droplets, and (3) chondrocytic phenotype of round cells surrounded by a sulfated proteoglycan-rich matrix. In addition, the hMPC 32F cells expressed differentiation lineage-specific genes, as detected by RT-PCR. Furthermore, osteogenic and adipogenic cultures responded to regulatory factors such as transforming growth factor-beta1 (TGF-beta1) and 1alpha, 25-dihydroxyvitamin D3 (1,25(OH)2D3). Thus, continuous treatment of osteogenic cultures for 2 weeks with TGF-beta1 decreased ALP activity and mRNA expression and inhibited osteocalcin mRNA expression and matrix mineralization, whereas l,25(OH)2D3 had an additive, stimulatory effect. In adipogenic cultures, treatment with TGF-beta1 for 2 weeks markedly inhibited adipogenesis whereas 1,25(OH)2D3 had no obvious effect. Finally, clonal analysis of hMPC 32F cells revealed a high percentage of multipotent clones, although clones of more restricted differentiation potential were also present. These characteristics of the hMPC 32F cell line suggest their pluripotent, progenitor, and nontransformed nature and indicate their potential application for studying the mechanisms governing developmental potential of adult human bone marrow mesenchymal progenitor cells.

Toxicology of environmental estrogens

It has been hypothesized that environmental contaminants that modulate endocrine signaling pathways may be causally linked to adverse health effects in humans. There has been particular concern regarding synthetic estrogens and their role in disrupting normal development of the male reproductive tract. Most estrogenic industrial compounds, such as bisphenol A (BPA) and nonylphenol, typically bind estrogen receptors alpha (ERalpha) and beta (ERbeta) and induce transactivation of estrogen-responsive genes/reporter genes, but their potencies are usually > or = 1,000-fold lower than observed for 17beta-estradiol (E2). Selective estrogen receptor modulators (SERMs) represent another class of synthetic estrogens that are being developed for treatment of hormone-dependent problems. The SERMs differentially activate wild-type ERalpha and variant forms expressing activation function 1 (ER-AF1) and AF2 (ER-AF2) in human HepG2 hepatoma cells transfected with a pC3-luciferase construct, and these in vitro differences reflect their unique in vivo biologies. The HepG2 cell assay has also been used in our laboratories to investigate the estrogenic activities of the following structurally diverse synthetic and phytoestrogens: 4'-hydroxytamoxifen; BPA; 2',4',6'-trichloro-4-biphenylol; 2',3',4',5'-tetrachloro-4-biphenylol; p-t-octylphenol; p-nonylphenol; naringenin; kepone; resveratrol; and 2,2-bis(p-hydroxyphenyl)-1,1,1-trichloroethane (HPTE). The results show that synthetic and phytoestrogens induce distinct patterns of gene activation in HepG2 and U2 osteogenic sarcoma cells, suggesting that these compounds will induce tissue-specific in vivo ER agonist or antagonist activities. The predicted differences between these compounds, based on results of the in vitro bioassay, have been confirmed. For example, BPA inhibits E2-induced responses in the rodent uterus, and HPTE and structurally related compounds are ERalpha agonists and ERbeta antagonists in assays carried out in HepG2 and other cancer cell lines.

Specific double-stranded RNA interference in undifferentiated mouse embryonic stem cells

Specific mRNA degradation mediated by double-stranded RNA (dsRNA) interference (RNAi) is a powerful way of suppressing gene expression in plants, nematodes, and fungal, insect, and protozoan systems. However, only a few cases of RNAi have been reported in mammalian systems. Here, we investigated the feasibility of the RNAi strategy in several mammalian cells by using the enhanced green fluorescent protein gene as a target, either by in situ production of dsRNA from transient transfection of a plasmid harboring a 547-bp inverted repeat or by direct transfection of dsRNA made by in vitro transcription. Several mammalian cells including differentiated embryonic stem (ES) cells did not exhibit specific RNAi in transient transfection. This long dsRNA, however, was capable of inducing a sequence-specific RNAi for the episomal and chromosomal target gene in undifferentiated ES cells. dsRNA at 8.3 nM decreased the cognate gene expression up to 70%. However, RNAi activity was not permanent because it was more pronounced in early time points and diminished 5 days after transfection. Thus, undifferentiated ES cells may lack the interferon response, similar to mouse embryos and oocytes. Regardless of their apparent RNAi activity, however, cytoplasmic extracts from mammalian cells produced a small RNA of 21 to 22 nucleotides from the long dsRNA. Our results suggest that mammalian cells may possess RNAi activity but nonspecific activation of the interferon response by longer dsRNA may mask the specific RNAi. The findings offer an opportunity to use dsRNA for inhibition of gene expression in ES cells to study differentiation.

Differential activation of wild-type and variant forms of estrogen receptor alpha by synthetic and natural estrogenic compounds using a promoter containing three estrogen-responsive elements

Structure-dependent estrogen receptor alpha (ER alpha) agonist and antagonist activities of synthetic and natural estrogenic compounds were investigated in human HepG2, MDA-MB-231 and U2 cancer cell lines. Compounds used in this study include 4'-hydroxytamoxifen, ICI 182,780, bisphenol-A (BPA), 2',4',6'-trichloro-4-biphenylol (3Cl-PCB-OH), 2',3',4',5'-tetrachloro-4-biphenylol (4Cl-PCB-OH), p-t-octylphenol, p-nonylphenol, naringenin, kepone, resveratrol, and 2,2-bis(p-hydroxyphenyl)-1,1,1-trichloroethane (HPTE). Cells were transfected with a construct (pERE(3)) containing three tandem estrogen responsive elements (EREs) and either wild-type estrogen receptor alpha (ER-wt) or variants expressing activation function-1 (ER-AF1) or AF-2 (ER-AF2). The ER agonist activities of the synthetic mono and dihydroxy aromatic compounds are comparable in all three-cell lines, whereas the activities of naringenin, kepone and resveratrol are dependent on cell context and expression of wild-type or variant forms of ER alpha. In contrast, the ER antagonist activities for these compounds were highly complex and, with the exception of 3Cl-PCB-OH, all compounds inhibited E2-induced wild-type or variant ER action. Results of this in vitro study suggest that the estrogenic and antiestrogenic activity of structurally diverse synthetic and natural estrogenic compounds is complex, and this is consistent with published data that often give contradictory results for these compounds.

Synthesis and crystal structure of a tubular sexithiophene

[structure: see text] The synthesis of a rigid, tubular sexithiophene is reported. Close intermolecular Cl.Cl interactions play a significant role in defining the crystal structure.

Differential effects of primary human immunodeficiency virus type 1 nef sequences on downregulation of CD4 and MHC class I

We analyzed two primary nef sequences, KS2 (subtype B) and K306 (subtype D), each directly isolated from patients. Cell lines constitutively expressing respective Nef proteins were constructed using a retroviral vector. There were significant differences in the ability to downregulate surface CD4 and MHC class I proteins between different nef sequences. When the nef sequence from NL432 was used as a reference, KS2 Nef demonstrated the highest ability to downregulate MHC class I, whereas it appeared to lack the ability to downregulate CD4. On the contrary, Nef from K306 decreased the level of surface CD4 to a greater extent, but was less effective on downregulation of MHC class I. These results showed that the levels of downregulation of CD4 and MHC class I could significantly vary among HIV strains and that two well-known functions of Nef, downregulation of CD4 and MHC class I, would be separated.

Synthesis of acetylenic cyclophanes via intramolecular self-assembly: evidence of perfluorophenyl-phenyl quadrupole interactions in the solution state

Reported herein is an example of a solution-state cross-coupling cyclization with an outcome mediated by perfluorophenyl-phenyl electrostatic interactions.

Targeted gene correction by small single-stranded oligonucleotides in mammalian cells

We demonstrate that relatively short single-stranded oligodeoxynucleotides, 25-61 bases homologous to the target sequence except for a single mismatch to the targeted base, are capable of correcting a single point mutation (G to A) in the mutant beta-galactosidase gene, in nuclear extracts, episome, and chromosome of mammalian cells, with correction rates of approximately 0.05%, 1% and 0.1%, respectively. Surprisingly, these short single-stranded oligonucleotides (ODN) showed a similar gene correction frequency to chimeric RNA-DNA oligonucleotide, measured using the same system. The in vitro gene correction induced by ODN in nuclear extracts was not dependent on the length or polarity of the oligonucleotide. In contrast, the episomal and chromosomal gene corrections were highly dependent on the ODN length and polarity. ODN with a homology of 45 nucleotides showed the highest frequency and ODN with antisense orientation showed a 1000-fold higher frequency than sense orientation, indicating a possible influence of transcription on gene correction. Deoxyoligonucleotides showed a higher frequency of gene correction than ribo-oligonucleotides of the identical sequence. These results show that a relatively short ODN can make a sequence-specific change in the target sequence in mammalian cells, at a similar frequency as the chimeric RNA-DNA oligonucleotide.

Synthesis and pharmacological evaluations of N-(substituted benzoylamino)-5-carbethoxymethyl-1,2,3,6-tetrahydropyridines as potential antiinflammatory agents

In a continuing effort to enhance antiinflammatory activities, a series of 1,2,3,6-tetrahydropyridines, 4-tert butyl (9a), 4-methoxy (9b), 2-fluoro (9c), 3-chloro (9d) and 3,4-dichloro (9e) benzoylamino-5-carbethoxymethyl-1,2,3,6-tetrahydropyridines, were synthesized and evaluated for their antiinflammatory activities. Antiinflammatory activities were screened in animal models employing carrageenan induced paw-edema assay on the male Sprague-Dawley rat. Relative potencies for carrageenan induced paw-edema assay were 1, 0.07, > 0.03, 0.14, 0.4 and 0.12 for indomethacin (IC50 = 3 mg/kg), 9a, 9b, 9c, 9d and 9e, respectively. These novel tetrahydropyridines were assessed for nonsteroidal antiinflammatory drug-mediated inhibition of nitric oxide generation in RAW 264.7 macrophage cell line using Griess' reagent. Relative potencies for inhibition of nitric oxide generation by macrophages stimulated with lipopolysaccharide (1 microgram/ml) were 1, 0.48, 0.44, 0.43, 0.45 and 0.45 for indomethacin (IC50 = 0.434 mM), 9a, 9b, 9c, 9d and 9e, respectively. The results show that novel tetrahydropyridines have moderate antiinflammatory activities and that they inhibit nitric oxide production by inhibiting inducible nitric oxide synthase.

Stable expression of human immunodeficiency virus type 1 Nef confers resistance against Fas-mediated apoptosis

To investigate the effect of Nef on Fas-mediated apoptosis, we compared T cells, both population and subclones stably expressing Nef from HIV-1(NL432), with Nef(-) control cells. Fas-mediated apoptosis was significantly delayed in Nef(+) cells as determined by annexin V staining and the percentage of apoptotic cells was lower in all Nef-expressing cells than in the control cells by a maximum of 10-fold. Next we measured cell surface levels of Fas to test whether the delayed apoptosis in Nef(+) cells was due to reduced cell surface expression of Fas. We found that there was no significant difference in the surface level of Fas between the Nef(+) and Nef(-) cells. To further define the steps affected by Nef in the Fas signaling pathway, the activation of caspase-3 and caspase-8 was investigated. A reasonable correlation was found between the magnitude of apoptosis measured by annexin V staining and the enzymatic activity of caspase-3. The overall level of caspase-8 activity in Nef(+) cells was also lower than in Nef(-) cells, although the extent of inhibition was not as significant as seen for caspase-3. Overall, our results indicate that long-term stable expression of Nef, which mimicks persistent or latent infection in vivo, confers resistance against anti-Fas Ab-induced apoptosis through inhibition of caspase-3 and caspase-8 activation.

Differential expression of tissue-specific promoters by gene gun

BACKGROUND

Tissue-specific promoters are becoming increasingly important in light of their effects on gene expression in gene therapy experiments. The regulation of gene expression may be as important as the delivery of the gene itself.

OBJECTIVES

To determine the effects of the involucrin (INV), keratin 14 (K14) and cytomegalovirus (CMV) promoters on the expression of the reporter gene beta-galactosidase.

METHODS

In vivo, plasmid DNA was introduced to BALB/c mice by gene gun. Skin biopsies were taken after 24 h for histology and beta-galactosidase staining. In tissue culture cells, plasmid DNA was introduced by transient transfection to cell lines 293 (transformed primary human embryonal kidney cells), NIH 3T3 (immortalized mouse fibroblasts) and human keratinocytes. Reporter gene expression was assayed by histochemical staining and chemiluminescence.

RESULTS

The K14 and INV promoter constructs showed beta-galactosidase gene expression only in the epidermis, while the CMV promoter showed gene expression in both the dermis and epidermis. In cell culture, the INV and K14 promoter constructs demonstrated significant beta-galactosidase expression in human keratinocytes, but minimal expression in 293 and NIH 3T3 cell types. CMV promoter constructs demonstrated significant expression in all cell types.

CONCLUSIONS

Gene expression can be regulated by different promoters both in vivo and in cell culture. Based on the physiological expression of the different promoters, gene expression can be restricted to certain cell types, tissues and skin layers.