Differentiation Generates Paracrine Cell Pairs That Maintain Basaloid Mouse Mammary Tumors: Proof of Concept

There is a paradox offered up by the cancer stem cell hypothesis. How are the mixed populations that are characteristic of heterogeneous solid tumors maintained at constant proportion, given their high, and different, mitotic indices? In this study, we evaluate a well-characterized mouse model of human basaloid tumors (induced by the oncogene Wnt1), which comprise mixed populations of mammary epithelial cells resembling their normal basal and luminal counterparts. We show that these cell types are substantially inter-dependent, since the MMTV LTR drives expression of Wnt1 ligand in luminal cells, whereas the functional Wnt1-responsive receptor (Lrp5) is expressed by basal cells, and both molecules are necessary for tumor growth. There is a robust tumor initiating activity (tumor stem cell) in the basal cell population, which is associated with the ability to differentiate into luminal and basal cells, to regenerate the oncogenic paracrine signaling cell pair. However, we found an additional tumor stem cell activity in the luminal cell population. Knowing that tumors depend upon Wnt1-Lrp5, we hypothesized that this stem cell must express Lrp5, and found that indeed, all the stem cell activity could be retrieved from the Lrp5-positive cell population. Interestingly, this reflects post-transcriptional acquisition of Lrp5 protein expression in luminal cells. Furthermore, this plasticity of molecular expression is reflected in plasticity of cell fate determination. Thus, in vitro, Wnt1-expressing luminal cells retro-differentiate to basal cell types, and in vivo, tumors initiated with pure luminal cells reconstitute a robust basal cell subpopulation that is indistinguishable from the populations initiated by pure basal cells. We propose this is an important proof of concept, demonstrating that bipotential tumor stem cells are essential in tumors where oncogenic ligand-receptor pairs are separated into different cell types, and suggesting that Wnt-induced molecular and fate plasticity can close paracrine loops that are usually separated into distinct cell types

Biatrial thrombi resembling myxoma regressed after prolonged anticoagulation in a patient with mitral stenosis: a case report

BACKGROUND: Many cases of cardiac masses have been reported in the literature, but in this case report we described a rare case of biatrial cardiac mass that represented a challenge for diagnosis and therapy. The differentiation between cardiac masses such as thrombi, vegetations, myxomas and other tumors is not always straightforward and an exact diagnosis is important because of its distinct treatment strategy. Transthoracic/esophageal echocardiography and cardiac magnetic resonance play an important role in establishing the diagnosis of cardiac masses. However, no current noninvasive diagnostic tool has the ability to absolutely diagnose cardiac masses; obtaining a pathological specimen by surgical resection of cardiac masses is the only reliable method to diagnose cardiac masses accurately. Our case report is an exception in that the final diagnosis was affirmed by empirical anticoagulation therapy based on clinical judgment and noninvasive characterization of biatrial mass. CASE PRESENTATION: We described a 54-year-old Malay man with severe mitral stenosis and atrial fibrillation who presented with a biatrial mass. Transthoracic/esophageal echocardiography and cardiac magnetic resonance detected a large, homogeneous right atrial mass typical of a thrombus, and a left atrial mass adhering to interatrial septum that mimicked atrial myxoma. The risk factors, morphology, location, and characteristics of the biatrial cardiac mass indicated a diagnosis of thrombi. However, our patient declined surgery. As a result, the nature of his cardiac masses was not specified by histology. Of note, his left atrial mass was completely regressed by long-term warfarin, leaving a residual right atrial mass. Thus, we affirmed the most probable diagnosis of cardiac thrombi. During the course of treatment, he had an episode of non-fatal ischemic stroke most probably because of a thromboembolism. CONCLUSIONS: Noninvasive characterization of cardiac mass is essential in clarifying the diagnosis and directing treatment strategy. Anticoagulation is a feasible treatment when the clinical assessment, risk factors, and imaging findings indicate a diagnosis of thrombi. After prolonged anticoagulation therapy, complete resolution of biatrial thrombi was achievable in our case

Surface characteristics and dissolution behavior of plasma-sprayed hydroxyapatite coating

plasma spraying, hydroxyapatite, coating, surface characteristic

Genome assembly of the milky mangrove Excoecaria agallocha

The milky mangrove Excoecaria agallocha is a latex-secreting mangrove that are distributed in tropical and subtropical regions. While its poisonous latex is regarded as a potential source of phytochemicals for biomedical applications, the genomic resources of E. agallocha remains limited. Here, we present a chromosomal level genome of E. agallocha, assembled from the combination of PacBio long-read sequencing and Omni-C data. The resulting assembly size is 1,332.45 Mb and has high contiguity and completeness with a scaffold N50 of 58.9 Mb and a BUSCO score of 98.4%, with 86.08% of sequences anchored to 18 pseudomolecules. 73,740 protein-coding genes were also predicted. The milky mangrove genome provides a useful resource for further understanding the biosynthesis of phytochemical compounds in E. agallocha.Full Tex

Chromosomal-level genome assembly and single-nucleotide polymorphism sites of black-faced spoonbill Platalea minor

202503 bcrcVersion of RecordRGCOthersCUHK Strategic Seed Funding for Collaborative Research Scheme; CUHK Group Research SchemePublishedC

Using growth rates to estimate age of the sea turtle barnacle Chelonibia testudinaria

Epibionts can serve as valuable ecological indicators, providing information about the behaviour or health of the host. The use of epibionts as indicators is, however, often limited by a lack of knowledge about the basic ecology of these ‘hitchhikers’. This study investigated the growth rates of a turtle barnacle, Chelonibia testudinaria, under natural conditions, and then used the resulting growth curve to estimate the barnacle’s age. Repeat morphometric measurements (length and basal area) on 78 barnacles were taken, as host loggerhead turtles (Caretta caretta) laid successive clutches at Mon Repos, Australia, during the 2015/16 nesting season. Barnacles when first encountered ranged in size from 3.7 to 62.9 mm, and were recaptured between 12 and 56 days later. Fitting the growth measurements of these barnacles to a von Bertalanffy growth curve, we estimated the age of these barnacles as a function of their size. Length growth rate decreased over time in a non-linear fashion, while basal area growth rate showed a linear relationship with age. The average estimated age of barnacles at first capture was approximately 6 months (barnacle length 30.3 ± 1.8 mm). The largest and oldest individual had a length of 62.9 mm when first measured, and was estimated to be 642 days old. The finding that C. testudinaria may live for up to 2 years, means that these barnacles may serve as interesting ecological indicators over this period. In turn, this information may be used to better understand the movement and habitat use of their sea turtle hosts, ultimately improving conservation and management of these threatened animals.An Unassigned Group, An Unassigned DepartmentNo Full Tex