MEK inhibition induces MYOG and remodels super-enhancers in RAS-driven rhabdomyosarcoma

The RAS isoforms are frequently mutated in many types of human cancers, including PAX3/PAX7 fusion-negative rhabdomyosarcoma. Pediatric RMS arises from skeletal muscle progenitor cells that have failed to differentiate normally. The role of mutant RAS in this differentiation blockade is incompletely understood. We demonstrate that oncogenic RAS, acting through the RAF-MEK [mitogen-activated protein kinase (MAPK) kinase]-ERK (extracellular signal-regulated kinase) MAPK effector pathway, inhibits myogenic differentiation in rhabdomyosarcoma by repressing the expression of the prodifferentiation myogenic transcription factor, MYOG. This repression is mediated by ERK2-dependent promoter-proximal stalling of RNA polymerase II at the MYOG locus. Small-molecule screening with a library of mechanistically defined inhibitors showed that RAS-driven RMS is vulnerable to MEK inhibition. MEK inhibition with trametinib leads to the loss of ERK2 at the MYOG promoter and releases the transcriptional stalling of MYOG expression. MYOG subsequently opens chromatin and establishes super-enhancers at genes required for late myogenic differentiation. Furthermore, trametinib, in combination with an inhibitor of IGF1R, potently decreases rhabdomyosarcoma cell viability and slows tumor growth in xenograft models. Therefore, this combination represents a potential therapeutic for RAS-mutated rhabdomyosarcoma.

Functional screening of FGFR4-driven tumorigenesis identifies PI3K/mTOR inhibition as a therapeutic strategy in rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is the most common pediatric soft tissue sarcoma and outcomes have stagnated, highlighting a need for novel therapies. Genomic analysis of RMS has revealed that alterations in the receptor tyrosine kinase (RTK)/RAS/PI3K axis are common and that FGFR4 is frequently mutated or overexpressed. Although FGFR4 is a potentially druggable receptor tyrosine kinase, its functions in RMS are undefined. This study tested FGFR4-activating mutations and overexpression for the ability to generate RMS in mice. Murine tumor models were subsequently used to discover potential therapeutic targets and to test a dual PI3K/mTOR inhibitor in a preclinical setting. Specifically, we provide the first mechanistic evidence of differential potency in the most common human RMS mutations, V550E or N535K, compared to FGFR4^wt overexpression as murine myoblasts expressing FGFR4^V550E undergo higher rates of cellular transformation, engraftment into mice, and rapidly form sarcomas that highly resemble human RMS. Murine tumor cells overexpressing FGFR4^V550E were tested in an in vitro dose-response drug screen along with human RMS cell lines. Compounds were grouped by target class, and potency was determined using average percentage of area under the dose-response curve (AUC). RMS cells were highly sensitive to PI3K/mTOR inhibitors, in particular, GSK2126458 (omipalisib) was a potent inhibitor of FGFR4^V550E tumor-derived cell and human RMS cell viability. FGFR4^V550E-overexpressing myoblasts and tumor cells had low nanomolar GSK2126458 EC₅₀ values. Mass cytometry using mouse and human RMS cell lines validated GSK2126458 specificity at single-cell resolution, decreasing the abundance of phosphorylated Akt as well as decreasing phosphorylation of the downstream mTOR effectors 4ebp1, Eif4e, and S6. Moreover, PI3K/mTOR inhibition also robustly decreased the growth of RMS tumors in vivo. Thus, by developing a preclinical platform for testing novel therapies, we identified PI3K/mTOR inhibition as a promising new therapy for this devastating pediatric cancer.

Pirfenidone inhibits post-traumatic proliferative vitreoretinopathy

PurposeThe purpose of the study was to evaluate the efficacy and safety of intravitreal pirfenidone for inhibition of proliferative vitreoretinopathy (PVR) in a model of penetrating ocular injury.Patients and methodsPenetrating trauma was induced on the retina of rabbit and treated either with 0.1 ml of phosphate-buffered saline (PBS) or 0.1 ml of 0.5% pirfenidone, and development of PVR was evaluated clinically and graded after 1 month. Histopathology and immunohistochemistry with transforming growth factor beta (TGFβ), alpha smooth muscle actin (αSMA), and collagen-1 were performed to assess the fibrotic changes. Expression of cytokines in the vitro-retinal tissues at different time points following pirfenidone and PBS injection was examined by RT-PCR. Availability of pirfenidone in the vitreous of rabbit at various time points was determined by high-performance liquid chromatography following injection of 0.1 ml of 0.5% pirfenidone. In normal rabbit eye, 0.1 ml of 0.5% pirfenidone was injected to evaluate any toxic effect.ResultsClinical assessment and grading revealed prevention of PVR formation in pirfenidone-treated animals, gross histology, and histopathology confirmed the observation. Immunohistochemistry showed prevention in the expression of collagen-I, αSMA, and TGFβ in the pirfenidone-treated eyes compared to the PBS-treated eyes. Pirfenidone inhibited increased gene expression of cytokines observed in control eyes. Pirfenidone could be detected up to 48 h in the vitreous of rabbit eye following single intravitreal injection. Pirfenidone did not show any adverse effect following intravitreal injection; eyes were devoid of any abnormal clinical sign, intraocular pressure, and electroretinography did not show any significant change and histology of retina remained unchanged.ConclusionThis animal study shows that pirfenidone might be a potential therapy for PVR. Further clinical study will be useful to evaluate the clinical application of pirfenidone.

Bilateral muscular axillary arch: An anatomic study and clinical considerations

The axillary arch is a variative muscular slip encountered in the axillary region which usually connects latissimus dorsi to pectoralis major. Reported here is a rare case of bilateral axillary arch splitting the radial nerve into two roots in each side as observed during routine dissection of the axillary region of an old male cadaver. The anatomy, surgical implications, and embryology of the anomalous muscle have been discussed. Clinicians should be aware of its existence as it can give rise to different pathologies. It should be recognised and excised to expose the axillary artery and vein in patients with trauma and to perform axillary lymphadenectomy or axillary bypass. It should be considered in the differential diagnosis of axillary masses or in a history of intermittent axillary vein obstruction.Journal of College of Medical Sciences-Nepal, 2014, Vol-10, No-3, 56-60

Holistic approach of Brain-Mind interaction

We live in three worlds – worlds 1, 2 and 3 with reciprocal interactions which make us perfect human beings. World 1 is the word of physical objects; it comprises the whole of cosmos of matter and energy enriched with nature’s contribution of flora and fauna, and all artefacts made by mankind in the form of books, machines, tools, arts and music. World 2 deals with the states of consciousness and subjective perceptions at three levels of human brain in succession: (a) outer sense provided by all our sense organs that gives rise to the development of (b) inner sense in the form of our emotions, memories, imagination and planning for the future; (c) finally at the core of world 2 there develops a sense of consciousness for self or ego. World 3 is created by man with the development of language of communication that uniquely relates to man. It is the world which is completely unknown to animals. All our means of communication and intellectual efforts are coded in books, the artistic and technological treasures are stored in the museum, and every artifact coded by man is preserved in the world 3. It is the world of civilization and culture. Education is the means whereby each human being is immersed in the world 3 throughout life, participating in the heritage of mankind and so becoming fully human. DOI: http://dx.doi.org/10.3126/jcmsn.v10i1.12768 Journal of College of Medical Sciences-Nepal, 2014, Vol.10(1); 43-48

BioAssay Research Database (BARD): chemical biology and probe-development enabled by structured metadata and result types

BARD, the BioAssay Research Database (https://bard.nih.gov/) is a public database and suite of tools developed to provide access to bioassay data produced by the NIH Molecular Libraries Program (MLP). Data from 631 MLP projects were migrated to a new structured vocabulary designed to capture bioassay data in a formalized manner, with particular emphasis placed on the description of assay protocols. New data can be submitted to BARD with a user-friendly set of tools that assist in the creation of appropriately formatted datasets and assay definitions. Data published through the BARD application program interface (API) can be accessed by researchers using web-based query tools or a desktop client. Third-party developers wishing to create new tools can use the API to produce stand-alone tools or new plug-ins that can be integrated into BARD. The entire BARD suite of tools therefore supports three classes of researcher: those who wish to publish data, those who wish to mine data for testable hypotheses, and those in the developer community who wish to build tools that leverage this carefully curated chemical biology resource.

A rare variation in the formation of the lower trunk of the brachial plexus its embryological basis and clinical importance - a case report

Brachial plexus is the plexus of nerves, that supplies the upper limb.Variations in the branches of brachial plexus are common but variations in the roots and trunks are very rare. Here, we report one of the such rare variations in the formations of the lower trunk of the brachial plexus in the right upper limb of a male cadaver. In the present case the lower trunk was formed by the union of ventral rami of C7,C8 and T1 nerve roots. The middle trunk was absent. Upper trunk formation was normal. Journal of College of Medical Sciences-Nepal,2011,Vol-6,No-4, 49-52 DOI: http://dx.doi.org/10.3126/jcmsn.v6i4.6727

RNAi screening identifies TAK1 as a potential target for the enhanced efficacy of topoisomerase inhibitors

In an effort to develop strategies that improve the efficacy of existing anticancer agents, we have conducted a siRNA-based RNAi screen to identify genes that, when targeted by siRNA, improve the activity of the topoisomerase I (Top1) poison camptothecin (CPT). Screening was conducted using a set of siRNAs corresponding to over 400 apoptosisrelated genes in MDA-MB-231 breast cancer cells. During the course of these studies, we identified the silencing of MAP3K7 as a significant enhancer of CPT activity. Follow-up analysis of caspase activity and caspase-dependent phosphorylation of histone H2AX demonstrated that the silencing of MAP3K7 enhanced CPT-associated apoptosis. Silencing MAP3K7 also sensitized cells to additional compounds, including CPT clinical analogs. This activity was not restricted to MDA-MB-231 cells, as the silencing of MAP3K7 also sensitized the breast cancer cell line MDA-MB-468 and HCT-116 colon cancer cells. However, MAP3K7 silencing did not affect compound activity in the comparatively normal mammary epithelial cell line MCF10A, as well as some additional tumorigenic lines. MAP3K7 encodes the TAK1 kinase, an enzyme that is central to the regulation of many processes associated with the growth of cancer cells (e.g. NF- κB, JNK, and p38 signaling). An analysis of TAK1 signaling pathway members revealed that the silencing of TAB2 also sensitizes MDA-MB-231 and HCT-116 cells towards CPT. These findings may offer avenues towards lowering the effective doses of Top1 inhibitors in cancer cells and, in doing so, broaden their application.

Left inferior accessory renal arteries its embryological basis and clinical significance

The variations in origin of renal arteries are very common. During routine dissection of a male cadaver we found left accessory renal artery. The origin of accessory renal artery is immediately below main renal artery. The left inferior accessory renal arteries run towards inferior pole of left kidney, in the area where the left renal vein was leaving the left kidney. The vascular variations are very important for vascular surgeons, urologists, nephrologists, radiologists. DOI: http://dx.doi.org/10.3126/jcmsn.v7i1.5976 JCMSN 2011; 7(1): 65-68

A study of sexual dimorphism in permanent mandibular canines and its implications in forensic investigations

Teeth are well preserved after death and they exhibit remarkable sexual dimorphism. Hence, they provide excellent materials for forensic investigations intended for identification of sex. Present study was undertaken on permanent mandibular canines of 90 male and 90 female subjects of age group 17-23 years. The mesiodistal width for right and left mandibular canines and intercanine distance were measured. Subsequently, canine index was calculated for both sides. Significant sexual dimorphism was found in all parameters except intercanine distance. All the results were compared with previous studies and discussed in the light of genetic, evolutionary and metabolic reasons for sexual dimporhism.

A morphometric study of human trachea and principal bronchi in different age groups in both sexes and its clinical implications

An extensive morphometric study of human trachea and principal bronchi was undertaken in the Department of Anatomy, Institute of Post Graduate Medical Education and Research, Kolkata, West Bengal, India, on 87 specimens procured from 51 male and 36 female relatively disease free fresh cadavers from Kolkata Police Morgue. The specimens were grouped into five age groups for both sexes. The length of trachea, principal bronchi, subcarinal angle was measured in each specimen. The external transverse diameter (width), internal transverse diameter and anteroposterior diameter (depth) were recorded at two different levels of trachea (junction of upper third and middle third; middle third and lower third) and middle of principal bronchi. Then the width-depth ratio was calculated. For each component of the measurements, standard error (SE), standard deviation (SD) and test of significance were calculated using independent sample't' test and multiple comparison test. The present investigation revealed a wide variation in different dimensions viz. length, transverse and anteroposterior diameters and width-depth ratio of upper and lower trachea and right and left principal bronchi and the subcarinal angle, in a same age group as well as in different age groups in both sexes. The study of these morphometric variations is of profound clinical importance as it may help the clinicians to understand the etiology of several pulmonary diseases and the surgeons to deal with resection and reconstruction of the tracheobronchial tree. This knowledge is also helpful for smooth conduction of some maneuvers like endotracheal intubation and bronchoscopic procedures.

Agenesis of isthmus of thyroid gland, its embryological basis and clinical significance--a case report

A wide range of morphological varieties and developmental anomalies of the thyroid gland have been reported in literature such as hypoplasia, ectopy, hemi agenesis, and agenesis. Out of these the incidence of agenesis of the isthmus of thyroid gland is rare and very few cases have been reported. In the present case report a male cadaver was found with agenesis of isthmus of thyroid gland with pyramidal lobe and levator glandulae thyroidae arising from right lobe.

Rare variations in the formation of median nerve--embryological basis and clinical significance

During routine dissection in the Department of Anatomy, CMS, Nepal, anomalous median nerves with regard to their formation were found in three different adult male cadavers. In one cadaver, there was variation in the formation of the median nerve and its relation with the axillary artery. Another cadaver revealed the formation of the median nerve by three roots, while in the third one, the median nerve was found to be formed by four roots. However, in each of the three cadavers the distribution of the anomalous median nerve was normal in arm, forearm and palm. The arterial pattern in the arm (axillary and brachial arteries) was also found to be normal. In each case the opposite upper limb was also meticulously dissected to exclude bilateral abnormality. However, in each case the anomaly was unilateral. Photographs of the abnormalities were taken for proper documentation. The variations related to the formation of median nerve by more than two roots are relatively uncommon as compared to the other types of varations of median nerve. Some embryological explanations are available to explain these variations. Finally, knowledge of these variations is important particularly to the surgeons for carrying out surgical procedures in axilla and arm.

Variation in relation of cords of brachial plexus and their branches with axillary and brachial arteries--a case report

Anatomical variations in the formation, course and distribution of brachial plexus are well documented. The present report describes some rare variations with regard to relation of cords of brachial plexus, median and ulnar nerves with the third part of axillary artery and brachial artery in the left upper limb of an adult male cadaver. All three cords of brachial plexus were noted to be lateral to all three parts of axillary artery. Median nerve was lateral to brachial artery and ulnar nerve was between the brachial artery and median nerve. Further distribution of median and ulnar nerves was normal. The arterial pattern in left arm (axillary and brachial arteries) was also normal. The findings were noted after thorough and meticulous dissection of both the upper limbs (axilla, arm, cubital fossa, forearm and palm) of the same cadaver in the Department of Anatomy, College of Medical Sciences, Bharatpur, Nepal. The right upper limb revealed no abnormality. It is important to be aware of such variations while planning a surgery in the region of axilla and arm as these nerves are more liable to be injured during surgical procedures. Possible embryological explanations and clinical significance have been discussed.

Information diffusion through blogspace

We study the dynamics of information propagation in environments of low-overhead personal publishing, using a large collection of WebLogs over time as our example domain. We characterize and model this collection at two levels. First, we present a macroscopic characterization of topic propagation through our corpus, formalizing the notion of long-running "chatter" topics consisting recursively of "spike" topics generated by outside world events, or more rarely, by resonances within the community. Second, we present a microscopic characterization of propagation from individual to individual, drawing on the theory of infectious diseases to model the flow. We propose, validate, and employ an algorithm to induce the underlying propagation network from a sequence of posts, and report on the results.

Variant insertion of coracobrachialis muscle-morphological significance, embryological basis and clinical importance

The coracobrachialis muscle in the arm is morphologically the sole representative of adductor group muscle in the arm, but such function during the process of evolution became insignificant in man. It is more important morphologically than functionally. Variant insertion of the coracobrachialis muscle was found during routine dissection of an adult male cadaver in the Department of Anatomy, College of Medical Sciences, and Bharatpur, Nepal. Normally the coracobrachialis muscle is inserted into the middle of the medial border of the humerus. In the present case an additional slender tendon passed inferiorly, crossing anterior to the median nerve and brachial artery, before attaching to the medial epicondyle of the humerus. Most of the proximal part of the tendon gave rise to an aponeurotic expansion that inserted into the distal medial border of the humerus. The tendinous insertion and aponeurotic expansion may represent a variant of the coracobrachialis longus (Wood's) muscle and the internal brachial ligament or the ligament of Struthers. The ulnar nerve was found to be traversing below the aponeurotic expansion. This type of anomalous insertion of coracobrachialis muscle may lead to compression of median nerve, brachial artery and ulnar nerve. Key words: Coracobrachialis muscle; ligament of Struthers; median nerve; brachial artery; ulnar nerve. DOI: 10.3126/jcmsn.v6i2.3616 Journal of college of Medical Sciences-Nepal, 2010, Vol.6, No-2, 42-46

Formation of median nerve by three roots: A case report

During routine dissection of an adult male cadaver in the Department of Anatomy, College of Medical Sciences, Bharatpur, Nepal, the right median nerve was found to be formed by three roots. The finding was noted after thorough and meticulous dissection of the upper limbs of both sides (axilla, arm, forearm and palm). Out of the three roots forming the anomalous median nerve, two were from lateral cord and one from medial cord of brachial plexus. However, the distribution of the anomalous median nerve was normal in arm, forearm and palm. The arterial pattern in the arm (axillary and brachial arteries) was also normal. Key words: Cadaver; median nerve; brachial plexus DOI: 10.3126/jcmsn.v6i1.3602 Journal of College of Medical Sciences-Nepal, 2010, Vol. 6, No. 1, 47-50