Selective type II TRK inhibitors overcome xDFG mutation mediated acquired resistance to the second-generation inhibitors selitrectinib and repotrectinib

Neurotrophic receptor kinase (NTRK) fusions are actionable oncogenic drivers of multiple pediatric and adult solid tumors, and tropomyosin receptor kinase (TRK) has been considered as an attractive therapeutic target for "pan-cancer" harboring these fusions. Currently, two generations TRK inhibitors have been developed. The representative second-generation inhibitors selitrectinib and repotrectinib were designed to overcome clinic acquired resistance of the first-generation inhibitors larotrectinib or entrectinib resulted from solvent-front and gatekeeper on-target mutations. However, xDFG (TRKAG667C/A/S, homologous TRKCG696C/A/S) and some double mutations still confer resistance to selitrectinib and repotrectinib, and overcoming these resistances represents a major unmet clinical need. In this review, we summarize the acquired resistance mechanism of the first- and second-generation TRK inhibitors, and firstly put forward the emerging selective type II TRK inhibitors to overcome xDFG mutations mediated resistance. Additionally, we concluded our perspectives on new challenges and future directions in this field.

Pathological Types,Expression of Mismatch Repair Protein,Human Epidermal Growth Factor Receptor 2,and Pan-TRK,and Eostein-Barr Virus Infection in Patients With Colorectal Cancer Resected in Tibet / 中国医学科学院学报

Objective To study the pathological types,expression of mismatch repair protein,human epidermal growth factor receptor 2(HER2),and Pan-TRK,and Epstein-Barr virus(EBV)infection in patients with colorectal cancer resected in Tibet. Methods A total of 79 patients with colorectal cancer resected in Tibet Autonomous Region People's Hospital from December 2013 to July 2021 were enrolled in this study.The clinical and pathological data of the patients were collected.The expression of mismatch repair protein,HER2,and Pan-TRK was detected by immunohistochemical(IHC)staining,and detection of HER2 gene by fluorescence in situ hybridization(FISH)in the patients with HER2 IHC results of 2+ or above.EBV was detected by in situ hybridization with EBV-encoded small RNA. Results A total of 79 colorectal cancer patients were included in this study,with the male-to-female ratio of 1.26:1 and the mean age of(57.06±12.74)years(24-83 years).Among them,4 patients received preoperative neoadjuvant therapy.Colonic cancer and rectal cancer occurred in 57(57/79,72.15%,including 31 and 26 in the right colon and left colon,respectively)and 22(22/79,27.85%)patients,respectively.The maximum diameter of tumor varied within the range of 1-20 cm,with the mean of(6.61±3.33)cm.Among the 79 colorectal cancer patients,75(75/79,94.94%)patients showed adenocarcinoma.Lymph node metastasis occurred in 12(12/21,57.14%)out of the 21 patients with severe tumor budding,13(13/23,56.52%)out of the 23 patients with moderate tumor budding,and 2(2/31,6.45%)out of the 31 patients with mild tumor budding,respectively.The lymph node metastasis rate showed differences between the patients with severe/moderate tumor budding and the patients with mild tumor budding(all P<0.001).The IHC staining showed that mismatch repair protein was negative in 10(10/65,15.38%)patients,including 5 patients with both MSH2 and MSH6 negative,4 patients with both MLH1 and PMS2 negative,and 1 patient with MSH6 negative.Pan-TRK was negative in 65 patients.The IHC results of HER2 showed 0 or 1+ in 60 patients and 2+ in 5 patients.FISH showed no positive signal in the 5 patients with HER2 IHC results of 2+.The detection with EBV-encoded small RNA showed positive result in 1(1/65,1.54%)patient. Conclusions Non-specific adenocarcinoma of the right colon is the most common in the patients with colorectal cancer resected in Tibet,and 15% of the patients showed mismatch repair protein defects.EBV-associated colorectal carcer is rare,Pan-TRK expression and HER2 gene amplification are seldom.The colorectal cancer patients with moderate and severe tumor budding are more likely to have lymph node metastasis.

Role of NTRK gene fusions and TRK inhibitors in non-small cell lung cancer / 中国肿瘤临床

Lung cancer is one of the major causes of cancer related deaths, and 80%–85% of lung cacer cases are non-small cell lung cancer (NSCLC). Most patients with NSCLC are already in the advanced stages when they are initially diagnosed. Despite remarkable advances in traditional chemotherapy, immunotherapy, and other therapies, the overall survival of patients with NSCLC remains poor. New therapeutic targets have been discovered in recent years with the continuous development of precision medicine, and the corresponding targeted drugs have highlighted the promise of targeted therapy. NTRK gene fusions have been closely related to the formation and progression of a variety of solid tumors. In patients with NSCLC, the incidence of NTRK gene fusions, which usually does not overlap with other common oncogene drivers, is approximately 0.2%. Clinical trials have demonstrated the good efficacy and safety of TRK inhibitors in solid tumors with NTRK gene fusions. In addition, patients with refractory NSCLC can benefit significantly from TRK inhibitors. This article reviews the role of NTRK gene fusions and TRK inhibitors in NSCLC.

Investigating Trk Protein Expression between Oropharyngeal and Non-oropharyngeal Squamous Cell Carcinoma: Clinical Implications and Possible Roles of Human Papillomavirus Infection / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: The relationship between head and neck squamous cell carcinoma (HNSCC) and subtypes of tropomyosin-related kinase (Trk) has not been studied in-depth. In this study, we evaluated the expression patterns of TrkA, TrkB, and panTrk and their clinicopathological significance as well as association with p16 expression and human papilloma virus (HPV) status. MATERIALS AND METHODS: Total of 396 radically resected oropharyngeal (n=121) and non-oropharyngeal (n=275) HNSCCs were included. Immunohistochemistry for TrkA, TrkB, and panTrk was performed. In addition, p16 immunohistochemistry was performed to assess the HPV status. Using HPV-negative HNSCC cell lines, FaDu and CAL27, HPV type 16 E6/E7 gene was transfected, and then changes of TrkA and TrkB expression were analyzed. RESULTS: In the clinical samples of HNSCC, high expression of TrkA and panTrk were more associated with oropharyngeal and p16 positive squamous cell carcinoma (SCC). In patients with completely resected (R0-resected) oropharyngeal SCC, high TrkA expression was related to superior overall survival and recurrence-free survival (RFS). In patients with R0-resected oral cavity SCC, high panTrk was related to poor RFS. In HPV type E6/E7 gene-transfected FaDu and CAL27 cell lines, increase of TrkA expression was observed. CONCLUSION: It seems that expression pattern of panTrk and TrkA differed according to anatomical sites of HNSCC and was closely related to p16 expression and patient prognosis. Trk expression should be considered in the context of anatomical site, p16 expression or HPV status and Trk subtypes.

Arsenic trioxide induces cell cycle arrest and affects Trk receptor expression in human neuroblastoma SK-N-SH cells

BACKGROUND: Arsenic trioxide (As2O3), a drug that has been used in China for approximately two thousand years, induces cell death in a variety of cancer cell types, including neuroblastoma (NB). The tyrosine kinase receptor (Trk) family comprises three members, namely TrkA, TrkB and TrkC. Various studies have confirmed that TrkA and TrkC expression is associated with a good prognosis in NB, while TrkB overexpression can lead to tumor cell growth and invasive metastasis. Previous studies have shown that As2O3 can inhibit the growth and proliferation of a human NB cell line and can also affect the N-Myc mRNA expression. It remains unclear whether As2O3 regulates Trks for the purposes of treating NB. METHODS: The aim of the present study was to investigate the effect of As2O3 on Trk expression in NB cell lines and its potential therapeutic efficacy. SK-N-SH cells were grown with increasing doses of As2O3 at different time points. We cultured SK-N-SH cells, which were treated with increasing doses of As2O3 at different time points. Trk expression in the NB samples was quantified by immunohistochemistry, and the cell cycle was analyzed by flow cytometry. TrkA, TrkB and TrkC mRNA expression was evaluated by real-time PCR analysis. RESULTS: Immunohistochemical and real-time PCR analyses indicated that TrkA and TrkC were over-expressed in NB, and specifically during stages 1, 2 and 4S of the disease progression. TrkB expression was increased in stage 3 and 4 NB. As2O3significantly arrested SK-N-SH cells in the G2/M phase. In addition, TrkA, TrkB and TrkC expression levels were significantly upregulated by higher concentrations of As2O3 treatment, notably in the 48-h treatment period. Our findings suggested that to achieve the maximum effect and appropriate regulation of Trk expression in NB stages 1, 2 and 4S, As2O3 treatment should be at relatively higher concentrations for longer delivery times;however, for NB stages 3 and 4, an appropriate concentration and infusion time for As2O3 must be carefully determined. CONCLUSION: The present findings suggested that As2O3 induced Trk expression in SK-N-SH cells to varying degrees and may be a promising adjuvant to current treatments for NB due to its apoptotic effects.

Effect of nalfurafi ne hydrochloride on the basal pressure of the sphincter of Oddi in anesthetized rabbits.

Background: Opioid analgesics, which are classifi ed as μ-opioid receptor agonists, are known to induce spasms or contraction of the sphincter of Oddi (SO), thereby inducing or exacerbating biliary diseases such as biliary obstruction, gallbladder dysfunction, cholelithiasis, pancreatitis, biliary dyskinesia, cholangitis, and cholecystitis. However, effects of κ-opioid receptor agonists on SO contraction have not been clarifi ed. In the present study, we investigated the effect of nalfurafi ne hydrochloride (nalfurafi ne), (E)-N-[17-(cyclopropylmethyl)-4,5α-epoxy-3,14-dihydroxymorphinan-6β-yl]-3- (furan-3-yl)-N-methylprop-2-enamide monohydrochloride, a selective κ-opioid receptor agonist, on spontaneous contraction of rabbit SO. Methods: SO contraction was measured using manometry in anesthetized rabbits. Rabbits were anesthetized with intravenous administration of 25 mg/kg sodium pentobarbital. An open tip catheter was inserted into the common bile duct toward the SO ampullae. Saline was perfused through the lumen of the open tip catheter at a constant rate of 6 ml/hr using a syringe pump. Nalfurafi ne, morphine, and pentazocine were intravenously (i.v.) administered and perfusion pressure was recorded. Results: Morphine (0.3 mg/kg, i.v.) and pentazocine (3 mg/kg, i.v.) were found to increase SO perfusion pressure, suggesting that these opioid analgesics may cause SO contraction. In contrast, nalfurafi ne (0.2 μg/kg, i.v.) decreased the perfusion pressure, indicating that this κ-opioid receptor agonist suppresses SO contraction. Conclusions: These fi ndings suggest that nalfurafi ne is unlikely to induce or exacerbate biliary diseases and may be safely used in patients with these disorders.

Nerve Regeneration Microenvironment in Pyridoxine-induced Ganglionopathy Rats Model Following Nerve Crush Injury / 中国康复理论与实践

@# Objective To evaluate the significance of molecular microenvironment in neurons for the nerve regeneration and repair by investigating the dynamic changes of nerve regrowth-associated proteins following bilateral sciatic nerves crush in pyridoxine-induced ganglionopathy rats model.Methods Bilateral sciatic nerve crush were performed 4 weeks after induction of pyridoxine-induced ganglionopathy. The changes of mean percentage of TUNEL positive cells in dorsal root ganglion (DRG) following bilateral sciatic nerves crush for 7 days, 14 days, 21 days, and 28 days. Western blotting techniques were used to investigate the expression of GAP-43 and trk A in different duration following sciatic nerve crush injury.Results The percentage of TUNEL positive neurons in DRG significantly increased in early stage and markedly decreased in 21～28 days after sciatic nerve crush. The expression of GAP-43 and trk A in DRG were upregulated at all time point after nerve injury in pyridoxine-induced ganglionopathy, but the overall level was lower than that of pure nerve crush injury.Conclusion In pyridoxine-induced ganglionopathy, neurons in DRG undergo survival crisis, the gene expression system was disintegrated, the capacity to regenerate their axons declines after nerve injury.

Base genética del cáncer papilar de la glándula tiroides y sus complicaciones / Genetic basis of papillary cancer of the thyroid gland and its complications

El tipo histológico más común de cáncer de tiroides es el cáncer papilar, comprende aproximadamente el 90% de la incidencia de cancer de tiroides. Alteraciones genéticas que incluyen reestructuraciones cromosómicas y mutaciones puntuales están implicadas en su patogénesis. las reestructuraciones cromosómicas incluyen reordenaciones del gen RET y del gen TRK, además de mutaciones puntuales en el gen BRAF y el gen RAS. Estas alteraciones genéticas que raramente ocurren simultaneamente en el tumor, producen señalizaciones aberrantes en la vía MAPK (mitogen-activated protón kinase). El desarrollo de nuevas modalidades terapéuticas en el cáncer de tiroides es crucial en aquellos tumores que han probado ser resistentes a la terapia con yodo radioactivo y a la supresión de hormona estimulante del tiroides.

Recent Progress in Research on Small Molecule Agonist of Neurotrophic Factor Receptor Trk / 国际脑血管病杂志

Neurotrophic factor activates signal pathways of intracellular phosphoinositide 3-kinase and extracellular signal-regulated kinase after acting on Trk receptor tyrosine kinase.It promotes the survival and differentiation of neurons.The development of small molecule Trk agonists of non-peptides and neurotrophic factor simulants can avoid a number of shortcomings of neurotrophic factors while agitating trk receptor signal transduction.It may provide a novel therapeutic approach for the treatment of nervous system diseases.

DNA Shuffling of Arabidopsis thalianna K+ Uptake Transporter Gene / 中国生物工程杂志

The DNA fragment sized 2 139bp, the same Sequence with AtKup1 gene from Arabidopsis thalianna was used as the templates for DNA family shuffling. The shuffeld AtKup1 gene library was expressed in the mutant of 5. cerevisae in which potassium transporter gene TRK1 and TRK2 were knocked out by homologous recombination. Then the screening was carried out in the low potassium media containing 5. 0 mmol/L KC1 and no histidine in it. it was found that both of diverse and wild AtKup1 gene can rescues the trk1△trk2△yeast mutant strain in low [ K + ] medium. The growth of 2 clones yeast containing diverse AtKup1 were beter than that of AtKup1 wild gene transformant. The sequencig results of the shuffeld AtKup1 showed that there were 2 nucleotide changed, which resulted in 2 amino acid variations in it compared with the original AtKup1. The potassium uptaking capacity of shuffled AtKup1 gene increased significantly when it was transformed into tobacco.

EFFECTS OF NERVE INJURY ON THE EXPRESSION OF Trk RECEPTOR PROTEINS LOCALIZED ON THE TRIGEMINAL MESENCEPHALIC NEURONS / 神经解剖学杂志

Immunofluorescence histochemistry combined with retrograde tracing technique was employed to observe the effects of masseteric nerve transection on the expression of Trk ( tropomyosin-related kinase) receptor proteins, namely TrkA, TrkB and TrkC in the trigeminal mesencephalic nucleus ( Me5 ) of the rat. At 7 and 14 days following transection of masseteric nerve through which Fluorogold (FG) was applied to identify the Me5 neurons innervating masseter, brain sections were immunohistochemically processed to detect the three Trk isoforms in FG-labeled Me5 neurons. With the percentage of double-labeled neurons to the total number of FG-labeled neurons as the index,we demonstrated ( 1 ) a significant increase in the percentage of TrkA-immunoreactive (IR) Me5 neurons at both 7 and 14 days after nerve transection, (2) no significant, but gradual, increase in the percentage of TrkB-IR Me5 neruons with longer survival time post transection and ( 3 ) little change of TrkC expression. The current findings indicate that axotomy differently affected the expression of the individual Trk receptors and these expression patterns may reflect an adaptation of the Me5 neurons to the peripheral nerve injury.

Immunohistochemical Expressions of TrkB and TrkC Receptors in Rat Cochleas with Amikacin-induced Ototoxicity / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Neurotrophins have been known to be responsible for the differentiation and survival of developing neurons as well as for aiding the recovery of adult neurons from injury. The neurotrophin family includes NGF, BDNF, NT-3, and NT-4/5, and they exert their biological functions through activation of the high-affinity binding receptors, that is trkA, trkB, and trkC, with high characteristic specificity. Previous studies indicate that spiral ganglion cells express trkB and trkC mRNAs, while auditory hair cells produce NT-3 mRNA that directly affect maturation and survival of auditory neurons. It has been reported that the loss of target innervation and the eventual degeneration of auditory neurons caused by aminoglycoside ototoxicity can be prevented by the infusion of neurotrophic factors. The purpose of this study is to provide the expression patterns of trkB and trkC in the normal chochleas and damaged cochleas with aminoglycoside ototoxicity. MATERIALS AND METHODS: Adult Sprague-Dawley rats were treated with amikacin 500 mg/kg for ten days, and sacrificed on the 7th, 14th, 21th, and 28th day following the last injection. Auditory brainstem response was measured in each animal. Immunohistochemical method was used to study the localization of trkB and trkC receptors in the cochleas of adult rats of either normal control group or ototoxicity group. RESULTS: Immunoreactivities to trkB and trkC receptors were strongly positive in the spiral ganglion cells of all cochleas, especially in the neuronal perikarya of the type I cells. No difference in staining pattern was seen among the cochleas with different hearing thresholds. CONCLUSION: The uniform expression pattern of trkB and trkC receptors in the spiral ganglion cells regardless of the degree of ototoxicity suggests that neurotrophic factors may bind to these receptors to initiate the cellular mechanisms for neuronal survival in the injured auditory system.

Tyrosine Protein Kinase (trk) Receptors Expression in Malignant Melanoma Cells / 대한피부과학회지

BACKGROUND: Nerve growth factor(NGF), brain derived neurotrophic factor(BDNF), neurotropin 3(NT-3) and neurotropir-4/5 are neurotrophic factors necessary for the development and maintenance of specific neurors. The tyrosine protein kinase(trk) receptors exhibit specificity for differ ent neurotrophins. NGF is the cognate ligand for the trk A receptor, BDNF binds to trk B receptor and NT-3 binds to irk A, trk B and trk C receptors, Since melanoma cells are devived from neural ectoderm, growth factors which affect neuronal tissue may have a role in melanoma biology. OBJECTIVE: The purpose of this study is to demonstrate the presence of trk receptors in rnelanoma cells and observe th effect of K-252a on these melanoma cells growth and differentiation. METHODS: After K252a over a range of 0-200nM was added into their cell lines, we exam ined cell viability of SK 28 and SK 30 cells. We performed this to examine the expression of the trk by flow cytometry and immunoblotting. RESULTS: 1. The incubation of SK 28 cells and SK 30 cells with K 252a resulted in a dose dependent inhibition of cell proliferation. 2. In the flowcytometry, SK 28 cells and SK 30 cells showed a high expression of trk A and trk B, not trk C. 3. Using immunoblottiiig, trk in SK 28 cells and SK 30 cells was not expressed. CONCLUSIONS: These results indicate that the identification of tyrosine protein kinase reeeptors and their inhibitor which affect differentiation and growth of a melanoma may provide an additional therapeutic option for treatment of melanoma.

Relationship between tyrosine protein kinase and synapse plasticity, learning and memory / 中国药理学通报

In recent years, the importance of tyrosine phosphorylation in the nervous system of mammalian is gaining recognition. Tyros ine protein kinases exert important modulatory effect on the proliferation, diff erentiation, migration and metabolism-related singal transduction pathways in c ells. In this paper we reviewed the signal cascade process of three different ty rosine protein kinase families, including Trk, Src and Eph tyrosine protein kina se families. Furthermore, we discussed important role and possible mechanisms of these tyrosine protein kinases on the neuron synapse plasticity and learning an d memory process.