Cbx4: A new guardian of p63's domain of epidermal control

Epigenetic regulators are essential for cell lineage choices during development. In this issue, Mardaryev et al. (2016. J. Cell Biol.http://dx.doi.org/10.1083/jcb.201506065) show that Polycomb subunit Cbx4 acts downstream of transcriptional regulator p63 to maintain epidermal progenitor identity and proliferation in the developing epidermis via Polycomb-dependent and -independent SUMO E3 ligase activities.

IL-1α is a DNA damage sensor linking genotoxic stress signaling to sterile inflammation and innate immunity

Environmental signals can be translated into chromatin changes, which alter gene expression. Here we report a novel concept that cells can signal chromatin damage from the nucleus back to the surrounding tissue through the cytokine interleukin-1alpha (IL-1α). Thus, in addition to its role as a danger signal, which occurs when the cytokine is passively released by cell necrosis, IL-1α could directly sense DNA damage and act as signal for genotoxic stress without loss of cell integrity. Here we demonstrate localization of the cytokine to DNA-damage sites and its subsequent secretion. Interestingly, its nucleo-cytosolic shuttling after DNA damage sensing is regulated by histone deacetylases (HDAC) and IL-1α acetylation. To demonstrate the physiological significance of this newly discovered mechanism, we used IL-1α knockout mice and show that IL-1α signaling after UV skin irradiation and DNA damage is important for triggering a sterile inflammatory cascade in vivo that contributes to efficient tissue repair and wound healing.

VPS53 mutations cause progressive cerebello-cerebral atrophy type 2 (PCCA2)

BACKGROUND

Progressive cerebello-cerebral atrophy (PCCA) leading to profound mental retardation, progressive microcephaly, spasticity and early onset epilepsy, was diagnosed in four non-consanguineous apparently unrelated families of Jewish Moroccan ancestry. Common founder mutation(s) were assumed.

METHODS

Genome-wide linkage analysis and whole exome sequencing were done, followed by realtime PCR and immunofluorescent microscopy.

RESULTS

Genome-wide linkage analysis mapped the disease-associated gene to 0.5 Mb on chromosome 17p13.3. Whole exome sequencing identified only two mutations within this locus, which were common to the affected individuals: compound heterozygous mutations in VPS53, segregating as expected for autosomal recessive heredity within all four families, and common in Moroccan Jews (∼1:37 carrier rate). The Golgi-associated retrograde protein (GARP) complex is involved in the retrograde pathway recycling endocytic vesicles to Golgi; c.2084A>G and c.1556+5G>A VPS53 founder mutations are predicted to affect the C-terminal domain of VPS53, known to be critical to its role as part of this complex. Immunofluorescent microscopy demonstrated swollen and abnormally numerous CD63 positive vesicular bodies, likely intermediate recycling/late endosomes, in fibroblasts of affected individuals.

CONCLUSIONS

Autosomal recessive PCCA type 2 is caused by VPS53 mutations.

Proposal for verification of the haldane phase using trapped ions

A proposal to use trapped ions to implement spin-one XXZ antiferromagnetic chains as an experimental tool to explore the Haldane phase is presented. We explain how to reach the Haldane phase adiabatically, demonstrate the robustness of the ground states to noise in the magnetic field and Rabi frequencies, and propose a way to detect them using their characteristics: an excitation gap and exponentially decaying correlations, a nonvanishing nonlocal string order, and a double degenerate entanglement spectrum. Scaling up to higher dimensions and more frustrated lattices, we obtain richer phase diagrams, and we can reach spin liquid phase, which can be detected by its entanglement entropy which obeys the boundary law.

Ranking of Prokaryotic Genomes Based on Maximization of Sortedness of Gene Lengths

How variations of gene lengths (some genes become longer than their predecessors, while other genes become shorter and the sizes of these factions are randomly different from organism to organism) depend on organismal evolution and adaptation is still an open question. We propose to rank the genomes according to lengths of their genes, and then find association between the genome rank and variousproperties, such as growth temperature, nucleotide composition, and pathogenicity. This approach reveals evolutionary driving factors. The main purpose of this study is to test effectiveness and robustness of several ranking methods. The selected method of evaluation is measuring of overall sortedness of the data. We have demonstrated that all considered methods give consistent results and Bubble Sort and Simulated Annealing achieve the highest sortedness. Also, Bubble Sort is considerably faster than the Simulated Annealing method.

A deletion mutation in TMEM38B associated with autosomal recessive osteogenesis imperfecta

Autosomal recessive osteogenesis imperfecta (OI) was diagnosed in three unrelated Israeli Bedouin consanguineous families. Fractures were evident in all cases in infancy. Genome-wide linkage analysis ruled out association with any of the known OI genes, and identified a single homozygosity locus of approximately 2 Mb on chromosome 9 common to all affected individuals (maximum multipoint lod score 6.5). Whole exome sequencing identified only a single mutation within this locus that was shared by all affected individuals: a homozygous deletion mutation of exon 4 of TMEM38B, leading to an early stop codon and a truncated protein, as well as low TMEM38B mRNA levels. TMEM38B encodes TRIC-B, a ubiquitous component of TRIC, a monovalent cation-specific channel involved in Ca(2+) release from intracellular stores that has been shown to act in cell differentiation. Molecular mechanisms through which a TMEM38B mutation might lead to an OI phenotype are yet to be explored.

Autosomal recessive Adams-Oliver syndrome caused by homozygous mutation in EOGT, encoding an EGF domain-specific O-GlcNAc transferase

Autosomal recessive Adams-Oliver syndrome was diagnosed in three remotely related Bedouin consanguineous families. Genome-wide linkage analysis ruled out association with known Adams-Oliver syndrome genes, identifying a single-homozygosity ∼1.8-Mb novel locus common to affected individuals (LOD score 3.37). Whole-exome sequencing followed by Sanger sequencing identified only a single mutation within this locus, shared by all affected individuals and found in patients from five additional apparently unrelated Bedouin families: a 1-bp deletion mutation in a predicted alternative splice variant of EOGT, leading to a putative truncated protein. RT-PCR demonstrated that the EOGT-predicted alternative splice variant is ubiquitously expressed. EOGT encodes EGF-domain-specific O-linked N-acetylglucosamine transferase, responsible for extracellular O-GlcNAcylation of epidermal growth factor-like domain-containing proteins, and is essential for epithelial cell-matrix interactions. F-actin staining in diseased fibroblasts showed apparently intact cell cytoskeleton and morphology, suggesting the EOGT mutation acts not through perturbation of cytoskeleton but through other mechanisms yet to be elucidated.

ZNF750 is expressed in differentiated keratinocytes and regulates epidermal late differentiation genes

Disrupted skin barrier due to altered keratinocyte differentiation is common in pathologic conditions such as atopic dermatitis, ichthyosis and psoriasis. However, the molecular cascades governing keratinocyte terminal differentiation are poorly understood. We have previously demonstrated that a dominant mutation in ZNF750 leads to a clinical phenotype reminiscent of psoriasis and seborrheic dermatitis. Here we show that ZNF750 is a nuclear protein bearing a functional C-terminal nuclear localization signal. ZNF750 was specifically expressed in the epidermal suprabasal layers and its expression was augmented during differentiation, both in human skin and in-vitro, peaking in the granular layer. Silencing of ZNF750 in Ca2+-induced HaCaT keratinocytes led to morphologically apparent arrest in the progression of late differentiation, as well as diminished apoptosis and sustained proliferation. ZNF750 knockdown cells presented with markedly reduced expression of epidermal late differentiation markers, including gene subsets of epidermal differentiation complex and skin barrier formation such as FLG, LOR, SPINK5, ALOX12B and DSG1, known to be mutated in various human skin diseases. Furthermore, overexpression of ZNF750 in undifferentiated cells induced terminal differentiation genes. Thus, ZNF750 is a regulator of keratinocyte terminal differentiation and with its downstream targets can serve in future elucidation of therapeutics for common diseases of skin barrier.

Autosomal recessive lethal congenital contractural syndrome type 4 (LCCS4) caused by a mutation in MYBPC1

Autosomal recessive lethal congenital contractural syndrome (LCCS) is a severe form of neuromuscular arthrogryposis. We previously showed that this phenotype is caused in two unrelated inbred Bedouin tribes by different defects in the phosphatidylinositol pathway. However, the molecular basis of the same phenotype in other tribes remained elusive. Whole exome sequencing identified a novel LCCS founder mutation within a minimal shared homozygosity locus of approximately 1 Mb in two affected individuals of different tribes: a homozygous premature stop producing mutation in MYBPC1, encoding myosin-binding protein C, slow type. A dominant missense mutation in MYBPC1 was previously shown to cause mild distal arthrogryposis. We now show that a recessive mutation abrogating all functional domains in the same gene leads to LCCS.

Meconium ileus caused by mutations in GUCY2C, encoding the CFTR-activating guanylate cyclase 2C

Meconium ileus, intestinal obstruction in the newborn, is caused in most cases by CFTR mutations modulated by yet-unidentified modifier genes. We now show that in two unrelated consanguineous Bedouin kindreds, an autosomal-recessive phenotype of meconium ileus that is not associated with cystic fibrosis (CF) is caused by different homozygous mutations in GUCY2C, leading to a dramatic reduction or fully abrogating the enzymatic activity of the encoded guanlyl cyclase 2C. GUCY2C is a transmembrane receptor whose extracellular domain is activated by either the endogenous ligands, guanylin and related peptide uroguanylin, or by an external ligand, Escherichia coli (E. coli) heat-stable enterotoxin STa. GUCY2C is expressed in the human intestine, and the encoded protein activates the CFTR protein through local generation of cGMP. Thus, GUCY2C is a likely candidate modifier of the meconium ileus phenotype in CF. Because GUCY2C heterozygous and homozygous mutant mice are resistant to E. coli STa enterotoxin-induced diarrhea, it is plausible that GUCY2C mutations in the desert-dwelling Bedouin kindred are of selective advantage.

Clinically meaningful efficacy of a non-estrogen agent: re-analysis of phase-2 data evaluating MF101

OBJECTIVE

To evaluate the level of reduction in hot flushes among a cohort of postmenopausal women randomized to a phase-2 clinical trial evaluating MF101, a selective estrogen receptor β modulator, for treatment of vasomotor symptoms to determine clinically meaningful efficacy.

METHODS

We performed a re-analysis of data from a double-blinded, placebo-controlled trial of 217 postmenopausal women randomized to treatment with MF101 or placebo for 12 weeks. At study termination, participants were asked if they were satisfied enough with medication to continue therapy.

RESULTS

Of the women treated, 73% with ≥50% reduction in hot flush frequency and 77% with ≥60% reduction in hot flush frequency were willing to continue treatment.

CONCLUSION

A 50-60% reduction in hot flushes is clinically meaningful among postmenopausal women who are being treated with a non-estrogen agent such as MF101.

Association analysis identifies ZNF750 regulatory variants in psoriasis

BACKGROUND

Mutations in the ZNF750 promoter and coding regions have been previously associated with Mendelian forms of psoriasis and psoriasiform dermatitis. ZNF750 encodes a putative zinc finger transcription factor that is highly expressed in keratinocytes and represents a candidate psoriasis gene.

METHODS

We examined whether ZNF750 variants were associated with psoriasis in a large case-control population. We sequenced the promoter and exon regions of ZNF750 in 716 Caucasian psoriasis cases and 397 Caucasian controls.

RESULTS

We identified a total of 47 variants, including 38 rare variants of which 35 were novel. Association testing identified two ZNF750 haplotypes associated with psoriasis (p < 0.05). We also identified an excess of rare promoter and 5'untranslated region (UTR) variants in psoriasis cases compared to controls (p = 0.041), whereas there was no significant difference in the number of rare coding and rare 3' UTR variants. Using a promoter functional assay in stimulated human primary keratinocytes, we showed that four ZNF750 promoter and 5' UTR variants displayed a 35-55% reduction of ZNF750 promoter activity, consistent with the promoter activity reduction seen in a Mendelian psoriasis family with a ZNF750 promoter variant. However, the rare promoter and 5' UTR variants identified in this study did not strictly segregate with the psoriasis phenotype within families.

CONCLUSIONS

Two haplotypes of ZNF750 and rare 5' regulatory variants of ZNF750 were found to be associated with psoriasis. These rare 5' regulatory variants, though not causal, might serve as a genetic modifier of psoriasis.

Histone modifiers in cancer: friends or foes?

Covalent modifications of histones can regulate all DNA-dependent processes. In the last few years, it has become more and more evident that histone modifications are key players in the regulation of chromatin states and dynamics as well as in gene expression. Therefore, histone modifications and the enzymatic machineries that set them are crucial regulators that can control cellular proliferation, differentiation, plasticity, and malignancy processes. This review discusses the biology and biochemistry of covalent histone posttranslational modifications (PTMs) and evaluates the dual role of their modifiers in cancer: as oncogenes that can initiate and amplify tumorigenesis or as tumor suppressors.

MRI versus breast-specific gamma imaging (BSGI) in the detection of synchronous breast cancer: A prospective head-to-head trial

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Background: Literature suggests that MRI identifies additional mammographically and sonographically occult cancers in 8-10% of newly diagnosed breast cancer patients. We have reported comparable sensitivity of BSGI to MRI in the detection of the known index cancer. We sought to prospectively compare BSGI to MRI in the identification of additional occult malignancies in newly diagnosed breast cancer patients.

Methods: Patients with newly diagnosed breast cancer from June 1, 2009 through February 4, 2011 were consented for an IRB approved protocol in which they underwent both breast MRI and BSGI. Each imaging study was read by a dedicated breast radiologist, with one reading all MRI, and another reading all BSGI studies. All subsequent biopsies were performed percutaneously under image guidance and reviewed by dedicated pathologists. The identification of additional occult breast cancers by MRI and BSGI was compared.

Results: Eighty-five patients underwent both MRI and BSGI. Twenty-one patients elected to undergo mastectomy without further management of imaging findings and were excluded, leaving 64 eligible patients. No additional lesions were found in 22 patients. Twenty-one patients had benign pathology on biopsied imaging findings. Metastatic axillary lymph nodes, satellite lesions or larger extent of disease was identified in 11 patients. Eleven occult breast cancers were identified in 10 patients (15.6%), 6 on MRI alone (9.4%), 3 on BSGI alone (4.7%), and 2 by both modalities (3.1%). There was no significant difference in the identification of occult cancer between MRI and BSGI (chi-square 0.77, p>0.1; Table).

Conclusions: BSGI has previously been shown to be as sensitive as MRI for detecting known invasive and in situ breast carcinoma. This study shows that BSGI is equally sensitive to MRI in the detection of synchronous mammographically and sonographically occult cancers in newly diagnosed breast cancer patients. Further research is needed to identify the false positive rates of BSGI and the effect on surgical management in comparison to MRI.

[Table: see text]

IL-1α and IL-1β recruit different myeloid cells and promote different stages of sterile inflammation

The immune system has evolved to protect the host from invading pathogens and to maintain tissue homeostasis. Although the inflammatory process involving pathogens is well documented, the intrinsic compounds that initiate sterile inflammation and how its progression is mediated are still not clear. Because tissue injury is usually associated with ischemia and the accompanied hypoxia, the microenvironment of various pathologies involves anaerobic metabolites and products of necrotic cells. In the current study, we assessed in a comparative manner the role of IL-1α and IL-1β in the initiation and propagation of sterile inflammation induced by products of hypoxic cells. We found that following hypoxia, the precursor form of IL-1α, and not IL-1β, is upregulated and subsequently released from dying cells. Using an inflammation-monitoring system consisting of Matrigel mixed with supernatants of hypoxic cells, we noted accumulation of IL-1α in the initial phase, which correlated with the infiltration of neutrophils, and the expression of IL-1β correlated with later migration of macrophages. In addition, we were able to show that IL-1 molecules from cells transfected with either precursor IL-1α or mature IL-1β can recruit neutrophils or macrophages, respectively. Taken together, these data suggest that IL-1α, released from dying cells, initiates sterile inflammation by inducing recruitment of neutrophils, whereas IL-1β promotes the recruitment and retention of macrophages. Overall, our data provide new insight into the biology of IL-1 molecules as well as on the regulation of sterile inflammation.

Abstract PD05-07: Use of Natural ER Beta Modulators in Treating Hormonal Therapy Resistant Breast Tumors

Although systemic hormone therapies that either block local estrogen production by aromatase inhibitors (AI) such as letrozole or block actions of estrogen/ER actions by anti-estrogens (AEs) like tamoxifen are well tolerated, unfortunately, essentially all breast cancers in women with advanced breast cancer develop resistance to these two classes of agents, and the benefit of adjuvant therapy (where micrometastatic disease is present but cannot be directly observed) is also limited by the development of resistance. In addition, side effects associated with the systemic inhibition of aromatase with current compounds limits their long-term utility of them as chemopreventative agents. We have investigated whether treatment of letrozole resistant breast cancer cells with selective plant-derived ER beta agonists (Liquiritigenin; LIQ or Nyasol; NYA) alone or in combination with letrozole affects the growth of AI resistant breast cancer cells, thereby restores sensitivity to AI. To test whether combination therapy restores sensitivity to letrozole, we have treated letrozole resistant breast cancer cells [LTLTca, derived from MCF-7-aromatase tumors resistant to letrozole] with either letrozole alone or with a combination of letrozole and LIQ/NYA. In addition, effects of these compounds on cell growth was also tested using different breast cancer cells including MCF-7, MCF-7-aromatase, ZR-75-1, ZR-75-aromatase, MDA-MB-231 along with tamoxifen resistant MCF-7 or MCF-7- PELP/ZR-75-PELP1. Compared to single agents, combination treatment not only restored sensitivity to letrozole but also resulted in decreased cell proliferation and increased apoptosis as well as increased ERα and decreased ERα levels in resistant cells. Combination of LIQ or NYA not only diminished cell growth in MCF-7-HER2, MCF-7-PELP1, and SKBR-3 breast cancer cells (that express endogenous aromatase) but also affected the expression of aromatase. Detailed investigations indicated that LIQ/NYA affects the induction of aromatase by specifically inhibiting breast cancer specific aromatase promoter 1.3 as well as its activity through inflammatory cytokine-mediated actions. These studies suggest the therapeutic benefit of LIQ or NYA ERα agonist to resensitize breast cancer cells that are resistant to AEs or AI and their ability to selectively inhibit tumor induction of aromatase. Our study suggests a novel role of natural ER beta agonists as valuable therapeutic modulators to treat endocrine sensitive as well as resistant tumors. (Supported by V-Foundation & P30 CA 54174, RRT)

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr PD05-07.

Abstract P5-01-03: MRI vs Breast Specific Gamma Imaging (BSGI) in Newly Diagnosed Breast Cancer: A Prospective Head-to-Head Trial

Introduction: Functional breast imaging is emerging as an adjunct to mammography and ultrasound in newly diagnosed breast cancer patients. Magnetic resonance Imaging (MRI) is the modality most widely employed. However, it is expensive, uncomfortable for certain patients, and interpretation is variable, depending upon a radiologist's expertise. Breast Specific Gamma Imaging (BSGI) has emerged as an alternative functional imaging study. While MRI evaluates differential enhancement of benign versus malignant lesions, BSGI evaluates the metabolic activity of normal versus abnormal cells by tagging mitochondria with Technecium99. In retrospective analyses, BSGI has been found to have similar sensitivity to MRI, but to date there has not been a prospective trial comparing these modalities in newly diagnosed breast cancer patients. We sought to prospectively compare BSGI to MRI in newly diagnosed breast cancer patients, to determine if this newer functional imaging study is as sensitive to MRI in detecting index lesions.

Methods: Patients with newly diagnosed invasive breast cancer from June 1, 2009 through May 31, 2010 were consented for an IRB approved protocol in which they underwent both breast MRI and BSGI. Each imaging study was read by a dedicated breast radiologist, with one radiologist reading all MRI, and another reading all BSGI studies. All subsequent biopsies were performed percutaneously, using image guidance. Patients were excluded if excisional biopsy was performed for diagnosis, or their MRI was performed at an outside facility. Patients with DCIS were also excluded. The sensitivity for each modality was calculated. Results: There were 53 patients enrolled in the study that had both MRI and BSGI for newly diagnosed invasive breast cancer. The sensitivity for MRI was 96% and for BSGI was 91% (Table 1) (P&gt;0.5, ns). There was one index tumor not seen on either MRI or BSGI. It was a 2mm invasive ductal carcinoma diagnosed by calcifications on mammogram. The other index tumor not seen on MRI was visualized on BSGI. Two of the remaining four index tumors not visualized on BSGI were located in the posterior breast. Two studies were false negative. These four lesions were visualized on MRI.

Discussion: In this prospective study comparing BSGI to MRI for newly diagnosed invasive breast cancer, BSGI was found to be as sensitive as MRI at detecting index lesions. Of the four false negative BSGI, two tumors were located near the chest wall, a known limitation of this technology. Larger prospective studies need to be performed to determine the true sensitivity and specificity of BSGI.

Pelizaeus-Merzbacher-like disease caused by AIMP1/p43 homozygous mutation

Pelizaeus-Merzbacher disease is an X-linked hypomyelinating leukodystrophy caused by PLP1 mutations. A similar autosomal-recessive phenotype, Pelizaeus-Merzbacher-like disease (PMLD), has been shown to be caused by homozygous mutations in GJC2 or HSPD1. We report a consanguineous Israeli Bedouin kindred with clinical and radiological findings compatible with PMLD in which linkage to PLP1, GJC2, and HSPD1 was excluded. Through genome-wide homozygosity mapping and mutation analysis, we demonstrated in all affected individuals a homozygous frameshift mutation that fully abrogates the main active domain of AIMP1, encoding ARS-interacting multifunctional protein 1. The mutation fully segregates with the disease-associated phenotype and was not found in 250 Bedouin controls. Our findings are in line with the previously demonstrated inability of mutant mice lacking the AIMP1/p43 ortholog to maintain axon integrity in the central and peripheral neural system.

The intervals between miniature end-plate potentials in the frog are unlikely to be independently or exponentially distributed

1. It has been suggested that spontaneous quantal release of transmitter at the neuromuscular junction is a Poisson process. One logical argument against accepting the Poisson hypothesis is that so far relatively few intervals between miniature end-plate potentials (min.e.p.p.s) have been studied in any single experiment. Release is known to occur from many sites on the nerve terminal, so many intervals must be studied before drawing any conclusions about the timing of release from the individual sites. Moreover, the statistical methods that have been used are relatively insensitive to deviations from Poisson predictions.2. The Poisson hypothesis is evaluated with respect to three major criteria:(a) The fit to the exponential distribution is analysed by five goodness of fit tests which were applied to eleven sets of data, showing that it is unlikely that the data sets were generated by an exponential distribution.(b) The independence of intervals is assessed in two ways. First, the autocorrelogram of intervals is constructed. This shows an excess of significant positive correlations beyond the 5% limits of the Poisson expectation. Secondly, the unsmoothed power spectrum is calculated, and compared to the Poisson prediction by means of the modified mean test. Again, most sets deviate significantly from the Poisson expectation. It is unlikely that the intervals are independent.(c) The possibility of simultaneous occurrences is evaluated by construction of the amplitude histogram of min.e.p.p.s. In all sets the Poisson prediction for the frequency of multiples of the unit height was exceeded by the empirical data sets. The over-all conclusion is that the process which generates spontaneous releases is unlikely to be Poisson.