Self-renewal and chemotherapy resistance of p75NTR positive cells in esophageal squamous cell carcinomas

<p>Abstract</p> <p>Background</p> <p>p75^NTRhas been used to isolate esophageal and corneal epithelial stem cells. In the present study, we investigated the expression of p75^NTRin esophageal squamous cell carcinoma (ESCC) and explored the biological properties of p75^NTR+cells.</p> <p>Methods</p> <p>p75^NTRexpression in ESCC was assessed by immunohistochemistry. p75^NTR+and p75^NTR-cells of 4 ESCC cell lines were separated by fluorescence-activated cell sorting. Differentially expressed genes between p75^NTR+and p75^NTR-cells were determined by real-time quantitative reverse transcription-PCR. Sphere formation assay, DDP sensitivity assay, ⁶⁴copper accumulation assay and tumorigenicity analysis were performed to determine the capacity of self-renewal, chemotherapy resistance and tumorigenicity of p75^NTR+cells.</p> <p>Results</p> <p>In ESCC specimens, p75^NTRwas found mainly confined to immature cells and absent in cells undergoing terminal differentiation. The percentage of p75^NTR+cells was 1.6%–3.7% in Eca109 and 3 newly established ESCC cell lines. The expression of Bmi-1, which is associated with self-renewal of stem cells, was significantly higher in p75^NTR+cells. p63, a marker identified in keratinocyte stem cells, was confined mainly to p75^NTR+cells. The expression of CTR1, which is associated with cisplatin (DDP)-resistance, was significantly decreased in p75^NTR+cells. Expression levels of differentiation markers, such as involucrin, cytokeratin 13, β1-integrin and β4-integrin, were lower in p75^NTR+cells. In addition, p75^NTR+cells generated both p75^NTR+and p75^NTR-cells, and formed nonadherent spherical clusters in serum-free medium supplemented with growth factors. Furthermore, p75^NTR+cells were found to be more resistant to DDP and exhibited lower ⁶⁴copper accumulation than p75^NTR-cells.</p> <p>Conclusion</p> <p>Our results demonstrated that p75^NTR+cells possess some characteristics of CSCs, namely, self-renewal and chemotherapy resistance. Chemotherapy resistance of p75^NTR+cells may probably be attributable to decreased expression of CTR1.</p

Genesis of Neuronal and Glial Progenitors in the Cerebellar Cortex of Peripuberal and Adult Rabbits

Adult neurogenesis in mammals is restricted to some brain regions, in contrast with other vertebrates in which the genesis of new neurons is more widespread in different areas of the nervous system. In the mammalian cerebellum, neurogenesis is thought to be limited to the early postnatal period, coinciding with end of the granule cell genesis and disappearance of the external granule cell layer (EGL). We recently showed that in the rabbit cerebellum the EGL is replaced by a proliferative layer called ‘subpial layer’ (SPL) which persists beyond puberty on the cerebellar surface. Here we investigated what happens in the cerebellar cortex of peripuberal rabbits by using endogenous and exogenously-administered cell proliferation antigens in association with a cohort of typical markers for neurogenesis. We show that cortical cell progenitors extensively continue to be generated herein. Surprisingly, this neurogenic process continues to a lesser extent in the adult, even in the absence of a proliferative SPL. We describe two populations of newly generated cells, involving neuronal cells and multipolar, glia-like cells. The genesis of neuronal precursors is restricted to the molecular layer, giving rise to cells immunoreactive for GABA, and for the transcription factor Pax2, a marker for GABAergic cerebellar interneuronal precursors of neuroepithelial origin that ascend through the white matter during early postnatal development. The multipolar cells are Map5+, contain Olig2 and Sox2 transcription factors, and are detectable in all cerebellar layers. Some dividing Sox2+ cells are Bergmann glia cells. All the cortical newly generated cells are independent from the SPL and from granule cell genesis, the latter ending before puberty. This study reveals that adult cerebellar neurogenesis can exist in some mammals. Since rabbits have a longer lifespan than rodents, the protracted neurogenesis within its cerebellar parenchyma could be a suitable model for studying adult nervous tissue permissiveness in mammals

Worldwide comparison of survival from childhood leukaemia for 1995–2009, by subtype, age, and sex (CONCORD-2): a population-based study of individual data for 89 828 children from 198 registries in 53 countries

Background Global inequalities in access to health care are reflected in differences in cancer survival. The CONCORD programme was designed to assess worldwide differences and trends in population-based cancer survival. In this population-based study, we aimed to estimate survival inequalities globally for several subtypes of childhood leukaemia. Methods Cancer registries participating in CONCORD were asked to submit tumour registrations for all children aged 0-14 years who were diagnosed with leukaemia between Jan 1, 1995, and Dec 31, 2009, and followed up until Dec 31, 2009. Haematological malignancies were defined by morphology codes in the International Classification of Diseases for Oncology, third revision. We excluded data from registries from which the data were judged to be less reliable, or included only lymphomas, and data from countries in which data for fewer than ten children were available for analysis. We also excluded records because of a missing date of birth, diagnosis, or last known vital status. We estimated 5-year net survival (ie, the probability of surviving at least 5 years after diagnosis, after controlling for deaths from other causes [background mortality]) for children by calendar period of diagnosis (1995-99, 2000-04, and 2005-09), sex, and age at diagnosis (< 1, 1-4, 5-9, and 10-14 years, inclusive) using appropriate life tables. We estimated age-standardised net survival for international comparison of survival trends for precursor-cell acute lymphoblastic leukaemia (ALL) and acute myeloid leukaemia (AML). Findings We analysed data from 89 828 children from 198 registries in 53 countries. During 1995-99, 5-year agestandardised net survival for all lymphoid leukaemias combined ranged from 10.6% (95% CI 3.1-18.2) in the Chinese registries to 86.8% (81.6-92.0) in Austria. International differences in 5-year survival for childhood leukaemia were still large as recently as 2005-09, when age-standardised survival for lymphoid leukaemias ranged from 52.4% (95% CI 42.8-61.9) in Cali, Colombia, to 91.6% (89.5-93.6) in the German registries, and for AML ranged from 33.3% (18.9-47.7) in Bulgaria to 78.2% (72.0-84.3) in German registries. Survival from precursor-cell ALL was very close to that of all lymphoid leukaemias combined, with similar variation. In most countries, survival from AML improved more than survival from ALL between 2000-04 and 2005-09. Survival for each type of leukaemia varied markedly with age: survival was highest for children aged 1-4 and 5-9 years, and lowest for infants (younger than 1 year). There was no systematic difference in survival between boys and girls. Interpretation Global inequalities in survival from childhood leukaemia have narrowed with time but remain very wide for both ALL and AML. These results provide useful information for health policy makers on the effectiveness of health-care systems and for cancer policy makers to reduce inequalities in childhood survival

Enhanced photoelectrochemical performance of Z-scheme g-C3N4/BiVO4 photocatalyst

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.BiVO 4 is a considerably promising semiconductor for photoelectrochemical water splitting due to its stability, low cost and moderate band gap. In this research, g-C 3 N 4 was proposed in Z-scheme configuration which boosted the performance of BiVO 4 up to four times. The experimental observations were counterchecked with Density Functional Theory (DFT) simulations. A TiO 2 /BiVO 4 heterojunction was developed and its performance was compared with that of g-C 3 N 4 /BiVO 4 . The photocurrent for g-C 3 N 4 /BiVO 4 was 0.42 mAcm −2 at 1.23 V vs. RHE which was the highest among g-C 3 N 4 based Z-scheme heterojunction devices. Lower charge transfer resistance, higher light absorption and more oxygen vacancy sites were observed for the g-C 3 N 4 based heterojunction. The simulated results attested that g-C 3 N 4 and BiVO 4 formed a van der Waals type heterojunction, where an internal electric field facilitated the separation of electron/hole pair at g-C 3 N 4 /BiVO 4 interface which further restrained the carrier recombination. Both the va lence and conduction band edge positions of g-C 3 N 4 and BiVO 4 changed with the Fermi energy level. The resulted heterojunction had small effective masses of electrons (0.01 m e ) and holes (0.10 m e ) with ideal band edge positions where both CBM and VBM were well above and below the redox potential of water.The authors would like to acknowledge financial support from Universiti Kebangsaan Malaysia through internal grant GUP-2016-089 and also for providing facilities to perform this research. H.U. acknowledges the supercomputing facilities of ESI Beowulf Cluster, University of Exeter, UK