Fibroblast growth factor receptors in cancer: genetic alterations,diagnostics, therapeutic targets and mechanisms of resistance

Fibroblast growth factor receptors (FGFRs) are aberrantly activated through single-nucleotide variants, gene fusions and copy number amplifications in 5–10% of all human cancers, although this frequency increases to 10–30% in urothelial carcinoma and intrahepatic cholangiocarcinoma. We begin this review by highlighting the diversity of FGFR genomic alterations identified in human cancers and the current challenges associated with the development of clinical-grade molecular diagnostic tests to accurately detect these alterations in the tissue and blood of patients. The past decade has seen significant advancements in the development of FGFR-targeted therapies, which include selective, non-selective and covalent small-molecule inhibitors, as well as monoclonal antibodies against the receptors. We describe the expanding landscape of anti-FGFR therapies that are being assessed in early phase and randomised controlled clinical trials, such as erdafitinib and pemigatinib, which are approved by the Food and Drug Administration for the treatment of FGFR3-mutated urothelial carcinoma and FGFR2-fusion cholangiocarcinoma, respectively. However, despite initial sensitivity to FGFR inhibition, acquired drug resistance leading to cancer progression develops in most patients. This phenomenon underscores the need to clearly delineate tumour-intrinsic and tumour-extrinsic mechanisms of resistance to facilitate the development of second-generation FGFR inhibitors and novel treatment strategies beyond progression on targeted therapy.Subject terms: Cancer, Cancer     

The Assembly of GM1 Glycolipid- and Cholesterol-Enriched Raft-Like Membrane Microdomains Is Important for Giardial Encystation

Although encystation (or cyst formation) is an important step of the life cycle of Giardia, the cellular events that trigger encystation are poorly understood. Because membrane microdomains are involved in inducing growth and differentiation in many eukaryotes, we wondered if these raft-like domains are assembled by this parasite and participate in the encystation process. Since the GM1 ganglioside is a major constituent of mammalian lipid rafts (LRs) and known to react with cholera toxin B (CTXB), we used Alexa Fluor-conjugated CTXB and GM1 antibodies to detect giardial LRs. Raft-like structures in trophozoites are located in the plasma membranes and on the periphery of ventral discs. In cysts, however, they are localized in the membranes beneath the cyst wall. Nystatin and filipin III, two cholesterol-binding agents, and oseltamivir (Tamiflu), a viral neuraminidase inhibitor, disassembled the microdomains, as evidenced by reduced staining of trophozoites with CTXB and GM1 antibodies. GM1- and cholesterol-enriched LRs were isolated from Giardia by density gradient centrifugation and found to be sensitive to nystatin and oseltamivir. The involvement of LRs in encystation could be supported by the observation that raft inhibitors interrupted the biogenesis of encystation-specific vesicles and cyst production. Furthermore, culturing of trophozoites in dialyzed medium containing fetal bovine serum (which is low in cholesterol) reduced raft assembly and encystation, which could be rescued by adding cholesterol from the outside. Our results suggest that Giardia is able to form GM1- and cholesterol-enriched lipid rafts and these raft domains are important for encystation.     

Evaluation of Hybridization Capture Versus Amplicon‐Based Methods for Whole‐Exome Sequencing

Next‐generation sequencing has aided characterization of genomic variation. While whole‐genome sequencing may capture all possible mutations, whole‐exome sequencing remains cost‐effective and captures most phenotype‐altering mutations. Initial strategies for exome enrichment utilized a hybridization‐based capture approach. Recently, amplicon‐based methods were designed to simplify preparation and utilize smaller DNA inputs. We evaluated two hybridization capture‐based and two amplicon‐based whole‐exome sequencing approaches, utilizing both Illumina and Ion Torrent sequencers, comparing on‐target alignment, uniformity, and variant calling. While the amplicon methods had higher on‐target rates, the hybridization capture‐based approaches demonstrated better uniformity. All methods identified many of the same single‐nucleotide variants, but each amplicon‐based method missed variants detected by the other three methods and reported additional variants discordant with all three other technologies. Many of these potential false positives or negatives appear to result from limited coverage, low variant frequency, vicinity to read starts/ends, or the need for platform‐specific variant calling algorithms. All methods demonstrated effective copy‐number variant calling when evaluated against a single‐nucleotide polymorphism array. This study illustrates some differences between whole‐exome sequencing approaches, highlights the need for selecting appropriate variant calling based on capture method, and will aid laboratories in selecting their preferred approach.     

Myeloid Mixed Lineage Kinase 3 Contributes to Chronic Ethanol-Induced Inflammation and Hepatocyte Injury in Mice

Proinflammatory activity of hepatic macrophages plays a key role during progression of alcoholic liver disease (ALD). Since mixed lineage kinase 3 (MLK3)-dependent phosphorylation of JNK is involved in the activation of macrophages, we tested the hypothesis that myeloid MLK3 contributes to chronic ethanol-induced inflammatory responses in liver, leading to hepatocyte injury and cell death. Primary cultures of Kupffer cells, as well in vivo chronic ethanol feeding, were used to interrogate the role of MLK3 in the progression of liver injury. Phosphorylation of MLK3 was increased in primary cultures of Kupffer cells isolated from ethanol-fed rats compared to cells from pair-fed rats. Kupffer cells from ethanol-fed rats were more sensitive to LPS-stimulated cytokine production; this sensitization was normalized by pharmacological inhibition of MLK3. Chronic ethanol feeding to mice increased MLK3 phosphorylation robustly in F4/80⁺ Kupffer cells, as well as in isolated nonparenchymal cells. MLK3^−/− mice were protected from chronic ethanol-induced phosphorylation of MLK3 and JNK, as well as multiple indicators of liver injury, including increased ALT/AST, inflammatory cytokines, and induction of RIP3. However, ethanol-induced steatosis and hepatocyte apoptosis were not affected by MLK3. Finally, chimeric mice lacking MLK3 only in myeloid cells were also protected from chronic ethanol-induced phosphorylation of JNK, expression of inflammatory cytokines, and increased ALT/AST. MLK3 expression in myeloid cells contributes to phosphorylation of JNK, increased cytokine production, and hepatocyte injury in response to chronic ethanol. Our data suggest that myeloid MLK3 could be targeted for developing potential therapeutic strategies to suppress liver injury in ALD patients.Key words: Alcoholic liver disease (ALD), Kupffer cells, Necroptosis, Toll-like receptor 4 (TLR4), Cytokines     

Exposure to Vehicular Pollution and Assessment of Respiratory Function in Urban Inhabitants

Particulate matter less than PM₁₀ and aromatic chemicals formed during incomplete combustion of organic matter are major environmental pollutants because of their toxic potential. The present study reports on the respiratory morbidity pattern of people exposed to auto exhaust as a result of the traffic load consisting of three varieties of vehicles (heavy, medium, and light) at three different points: North (B), South (E), and Central (C) regions of Kolkata, India. Particle size distribution was analyzed by an Anderson cascade impactor and volatile organic compounds (VOCs) were analyzed by sorbent tube and capillary gas chromatography with flame ionization detector. Levels of VOCs, particularly benzene and toluene (at B, 15.2 and 20.1 μg/m³; at E, 67.4 and 74.6 μg/m³, and at C, 40.7 and 61.3 μg/m³, respectively), were found to be appreciably high in three sites in Kolkata compared with the values reported by the U.S. EPA. PM₁₀ concentrations also have been found to be higher than the Central Pollution Control Board of India’s permissible standard (≤10 μm: B, 535.9; E, 909.2; C, 1114.5 μg/m³; <10–3.3 μm: B, 269.8 μg/m³; E, 460.1; C, 679.2 μg/m³; and <3.3–0.4 μm: B, 266.1; E, 449.1; C, 435.3 μg/m³). Pulmonary function tests (PFT) of 505 inhabitants were performed in the three different areas using Spirovit SP-10 and Wrights peak flowmeter. The traffic load in the vicinity supported the occurrence of higher respiratory functional deterioration. PFT status showed restrictive (3.76%), obstructive (3.17%), and combined restrictive and obstructive types (1.98%) of impairment. Higher restrictive impairments in males might be due to their combined occupational and environmental exposures. The rate of increase of the number of vehicles on the roads of the city adds to the risk of greater problems due to exposure to hazardous substances that are less than PM₁₀, in particular, polycyclic aromatic hydrocarbons and VOCs. An erratum to this article can be found at     

Changing trends of an endemic trauma

The incidence of severe burn is extremely high in the Low and Middle Income Countries with an estimated 90% of the world incidence of which 50% is in South East Asia. Through an earlier analysis of 11,196 burn admission over 8 years (1993–2000—Phase I) to our burn unit we established the endemic nature of the injury [Ahuja RB, Bhattacharya S. An analysis of 11,196 burn admissions and evaluation of conservative management techniques. Burns 2002;28:555–61]. A continued analysis of 5566 burn admissions over the next 7 years (2001–2007—Phase II) and its comparison with the Phase I reveals a significant change in the epidemiological profile. The average yearly admissions have fallen by 43.14%, from 1399.5 patients in Phase I to 795.14 patients in Phase II. This fall in average yearly admissions is predominant in the age group 16–35 years (52.61% decline) and 36–55 years (46.51% decline). The overall female to male ratio has also changed from 1.26:1 to 0.91:1. However, the overall mean %TBSA burn has reduced only mildly from 49.12% TBSA in Phase I to 44.39% in Phase II. During Phase II there was also a significant decline of 46.93% and 56.25% in the yearly admission of flame and scald burn respectively. Non-intentional incidents still remain the main mode of injury accounting for 87.12% in Phase I and 89.89% in Phase II. But, the yearly admissions of non-intentional burns fell from 1219.25 in Phase I to 714.71 in Phase II, which is a significant drop of 41.38%. Kitchen continues to dominate as the main location for flame incidents, but the yearly admission rate from kitchen accidents dropped from 897.5 patients in Phase I to 368.43 patients in Phase II. At the same time, liquefied petroleum gas (LPG) leaks which accounted for only 0.72% of all kitchen accidents in Phase I rose to 10.74% in Phase II. Another redeeming feature is the reduction in overall mortality from 51.8% in Phase I to 40.20% in Phase II. Interestingly, a very significant negative correlation exists (being significant at 0.01 level—2 tailed) between burn admissions and the yearly per-capita income of Delhi, from 1993 to 2005, to prove that the incidence and profile of burns directly reflects the economic development of the society. We see this as the first long term study from a burn unit of a developing country to directly reflect this association of burn incidence and its changing profile with economic prosperity.     

Multiple myeloma presenting as acute pancreatitis.

Acute pancreatitis is a very uncommon presenting feature of multiple myeloma. We report an elderly non-alcoholic man presenting with acute abdominal pain and rapidly progressing renal failure. Investigations revealed lytic lesions in the vertebrae and skull, M band on urine electrophoresis, and radiological and biochemical evidence of acute pancreatitis. The patient died despite conservative management of the pancreatitis.