Complete response to capmatinib in a patient with metastatic lung adenocarcinoma harboring CD47-MET fusion: a case report.

Comprehensive genomic profiling is highly recommended for treatment decision in nonsquamous, non-small cell lung cancer (NSCLC). However, rare genomic alterations are still being unveiled, with scarce data to guide therapy. Herein, we describe the treatment journey of a 56-year-old, never-smoker Caucasian woman with a metastatic NSCLC harboring a CD47-MET fusion, initially classified as a variant of unknown significance. She had undergone 3 lines of therapy over the course of 3 years, including chemotherapy, immunotherapy, and anti-angiogenic therapy. After reanalysis of her next-generation sequencing data in our service, the fusion was reclassified as likely oncogenic. The patient was started with fourth-line capmatinib, with a good tolerance so far and a complete metabolic response in the active sites of disease, currently ongoing for 18 months. In conclusion, we highlight the sensitivity of a novel MET fusion to capmatinib and emphasize the need for comprehensive panels in NSCLC and molecular tumor board discussions with specialized centers when rare findings arise.

Efficacy and safety analysis of immunotherapy in non-small cell lung cancer patients with MET alterations.

BACKGROUND: Mesenchymal epithelial transition factor (MET) is a rare oncologic driver gene, and information on immunotherapy for non-small cell lung cancer (NSCLC) patients with this driver gene is limited. Here we evaluate the efficacy and safety of immune checkpoint inhibitors (ICI) under different therapeutic regimen for NSCLC patients with MET alterations. METHODS: From June 2019 to December 2023, we assessed the efficacy and toxicity of ICIs in 42 NSCLC patients with MET alterations. Survival curves were plotted using the Kaplan-Meier method and the Cox proportional hazards model applied for univariate and multivariate analyses. We assessed the size of target lesion according to RECIST v1.1, and objective response rate (ORR) was defined as the sum of complete response (CR) and partial response (PR), disease control rate (DCR) as the sum of CR, PR, and disease stable. RESULTS: A total of 42 NSCLC patients with MET alterations were included in this retrospective study, 10 was MET 14 skipping mutation and 32 was MET amplification. The ORR for ICI treatment was 30.95% and the DCR was 71.43%. Median progression-free survival (mPFS) and median overall survival (OS) were 4.40 and 13.97 months, respectively. There exists statistical differences between the mPFS of ICI monotherapy and combine ICI therapy (2.8 vs 7.8 months, p = 0.022). The incidence of drug-related adverse reactions was 47.62%, mainly bone marrow suppression (14.28%), immune-related pneumonia (7.14%), and liver function impairment (7.14%), and six patients (14.28%) experiencing grade 3 or above adverse events. CONCLUSION: NSCLC patients with MET alterations can benefit from immunotherapy, especially the patients treated by combined ICI therapy. However, special attention should be paid to the occurrence of grade 3/4 adverse reactions while using the combined ICI therapy.

MET overexpression correlated with prognosis of EGFR-mutant treatment­naïve advanced lung adenocarcinoma: a real­world retrospective study.

BACKGROUND: About 50-60% treatment-naïve advanced non-small-cell lung cancers were coexistence of epidermal growth factor receptor (EGFR) and mesenchymal epithelial transition (MET) overexpression. However, few studies demonstrated the prognostic value of MET protein expression in untreated EGFR-mutant lung adenocarcinoma (LUAD). METHODS: A total of 235 EGFR-mutant untreated advanced LUAD patients were retrospectively enrolled. MET expression was determined using immunohistochemistry, and MET positivity was defined as 2 + or 3 + using the METmab scoring algorithm. Progression-free survival (PFS) and overall survival (OS) were analysed according to MET expression status. Independent factors predicting prognosis were identified using multivariate Cox regression analyses. RESULTS: Of the 235 patients, 113 (48.1%) harboured exon 19 deletion (19_del), 103 (43.8%) had exon 21 L858R mutations, and 19 (8.1%) had other mutation types, including exon 21 L861Q, exon 18 G719A/C, exon 20 S768I, and L858R/19_del double mutations. MET-positive expression was observed in 192 (81.7%) cases. There was no significant difference in baseline clinicopathological characteristics between MET positivity and MET negativity groups. Patients were stratified by different EGFR mutation subtypes. MET-positive patients in the L858R mutation subgroup had markedly shorter PFS and OS than MET-negative patients (median PFS: 13 versus 27.5 months, p < 0.001; median OS: 29 versus not reached, p = 0.008), but no significant difference was observed in the 19_del subgroup. Multivariate Cox regression analyses indicated that MET positivity was an independent predictor for poor PFS and OS in L858R subgroup (PFS: HR = 3.059, 95% CI 1.552-6.029, p = 0.001; OS: HR = 3.511, 95% CI 1.346-9.160, p = 0.010). Additionally, an inferior survival outcome of MET positivity was observed in the L858R mutation subgroup when treated with EGFR-tyrosine kinase inhibitor (TKI) monotherapy as the first-line regimen (median PFS: 13 versus 36.5 months, p < 0.001; median OS: 29 versus not reached, p = 0.012) but not with EGFR-TKI plus platinum doublet chemotherapy. CONCLUSIONS: MET positive expression was an independent predictor of poor outcomes in untreated EGFR L858R mutation advanced LUAD patients treated with first-line EGFR-TKI monotherapy.

MET alterations in advanced non-small cell lung cancer.

Precision medicine has helped identify several tumor molecular aberrations to be treated with targeted therapies. These therapies showed substantial improvement in efficacy without excessive toxicity in patients with specific oncogenic drivers with advanced cancers. In metastatic lung cancers, the implementation of broad platforms for molecular tumor sequencing has helped oncology providers identify oncogenic drivers linked with better outcomes when treated upfront with targeted therapies. Mesenchymal-epithelial transition factor (MET) alterations are present in up to 60% of non-small cell lung cancer and are associated with a poor prognosis. Capmatinib and tepotinib are currently the only two approved targeted therapies by the U.S. Food and Drug Administration (FDA) for patients with MET exon 14 skipping mutation. Several agents are being developed to tackle an unmet need in patients with MET alterations. Some of these agents are being used in combination with EGFR targeted therapy to mitigate resistance to EGFR inhibitor. These agents are poised to provide new hope for these patients.

Mesenchymal-Epithelial Transition Kinase Inhibitor Therapy in Patients with Advanced Papillary Renal-Cell Carcinoma: A Systematic Review and Meta-Analysis.

Papillary subtypes of renal-cell carcinoma (pRCC) represent 10-15% of the cases and commonly have MET alterations. This systematic review and single-arm meta-analysis evaluated MET inhibitor therapy (METi) efficacy and safety in adults with confirmed advanced pRCC. The search strategy included PubMed, Web-of-science, Cochrane, and Scopus. We used the DerSimonian/Laird random effect model for all analyses; p-value < 5% was considered significant, and heterogeneity was assessed with I2. Three clinical trials and six cohort studies were included with 504 patients; 31% were MET-driven. Our pooled analysis demonstrated an objective response rate (ORR) in MET-driven, MET-independent, and overall patients of: 36% (95%CI: 10-62), 0% (95%CI: 0-3), and 21% (95%CI: 1-41), respectively. One-year disease control and progression-free survival rates were, respectively, 70% (95%CI: 52-88) and 15% (95%CI: 10-20). Twelve- and twenty-four-month survival rates were, respectively, 43% (95%CI: 23-64) and 10% (95%CI: 0-30). The prevalence of adverse events of any grade and grades 3-5 were 96% (95%CI: 91-100) and 44% (95%CI: 37-50), respectively. We suggest METi has anti-tumor activity and is tolerable in patients with advanced pRCC.

Selpercatinib and capmatinib combination promotes sustained complete response in novel ISOC1-RET fusion lung cancer after resistance to RET inhibitor via MET amplification: Case Report.

RET fusions occur in 1-2% of non-small cell lung cancer. Selpercatinib and pralsetinib are selective RET inhibitors with significant improvement of outcome in patients with tumor harboring RET fusion; however, resistance mechanisms appear frequently, mainly driven by MAPK pathway bypass, secondary RET mutations, or in 5% via MET amplification. Co-inhibition of RET and MET is a compelling strategy for overcoming MET-dependent resistance to RET inhibitors and potentially other inhibitors. To our knowledge, this is the first report of a novel ISOC1-RET fusion lung cancer with a durable complete response to selpercatinib, with resistance via MET amplification, which was overcome by the successful combination of selpercatinib and capmatinib.

Interaction of Val66Met BDNF and 5-HTTLPR polymorphisms with prevalence of post-earthquake 27-F PTSD in Chilean population.

Post-traumatic stress (PTSD) disorder is a mental health condition that can occur after experiencing or witnessing a traumatic event. The 27-F earthquake that struck Chile in 2010 was one such event that had a significant impact on the mental health of the population. A study was conducted to investigate the prevalence of PTSD and its associated factors among survivors of this earthquake. The study was a longitudinal design, involving a sample of 913 patients aged 18 to 75 years who attended 10 Primary Care Centers in Concepción, Chile. The Composite International Diagnostic Interview (CIDI) was used to assess both depressive episodes (DE) and PTSD before and after the earthquake. The study also involved genotyping studies using saliva samples from the participants, specifically focusing on the Val66Met and 5-HTTLPR polymorphisms. Statistical analysis was performed to examine the association between different variables and the presence of PTSD. These variables included demographic factors, family history of psychiatric disorders, DE, childhood maltreatment experiences, and critical traumatic events related to the earthquake. The results showed that the incidence of post-earthquake PTSD was 11.06%. No significant differences were found between the groups of participants who developed post-earthquake PTSD regarding the Val66Met or 5-HTTLPR polymorphisms. However, a significant association was found between the concomitant diagnosis of DE and the development of post-earthquake PTSD. The presence of DE doubled the risk of developing post-earthquake PTSD. The number of traumatic events experienced also had a statistically significant association with an increased risk of developing post-earthquake PTSD. The study's limitations include the potential interference of different DE subtypes, the complexity of quantifying the degree of earthquake exposure experienced by each individual, and events entailing social disruption, such as looting, that can profoundly influence distress. In conclusion, the study found that PTSD following the 27-F earthquake in Chile was associated with a concomitant diagnosis of DE and the number of traumatic events experienced. The study did not find a significant association between PTSD and the Val66Met or 5-HTTLPR polymorphisms. The researchers recommend that mental health professionals should prioritize the detection and treatment of concomitant depressive episodes and exposure to critical traumatic events in survivors of disasters. They also suggest that further research is needed to better understand the relationship between genetic factors and post-disaster PTSD.

Nonextensive realizations in interacting ion channels: Implications for mechano-electrical transducer mechanisms.

We propose a theoretical model to investigate the thermodynamics of single and coupled two-state ion channels, associated with mechanoelectrical transduction (MET) and hair cell biophysics. The modeling was based on the Tsallis nonextensive statistical mechanics. The choice for a nonextensive framework in modeling ion channels is encouraged on the fact that we take into account the presence of interactions or long-range correlations in the dynamics of single and coupled ion channels. However, the basic assumptions that support Boltzmann-Gibbs statistics, traditionally used to model ion channel dynamics, state that the system is formed by independent or weakly interacting elements. Despite being well studied in many biological systems, the literature has not yet addressed the study of both entropy and mutual information related to isolated or physically interacting pairs of MET channels. Inspired by hair cell biophysics, we show how the presence of nonextensivity, or subadditivity and superadditivity modulates the nonextensive entropy and mutual information as functions of stereocilia displacements. We also observe that the magnitude of the interaction between the two channels, given by a nonextensive parameter, influences the amplitude of the nonextensive joint entropy and mutual information as functions of the hair cell displacements. Finally, we show how nonextensivity regulates the current versus displacement curve for a single and a pair of interacting two-state channels. The present findings shed light on the thermodynamic process involved in the molecular mechanisms of the auditory system.

Influential Serum Kinases (Non-sFlt-1) and Phosphatases in Preeclampsia-Systemic Review and Metanalysis.

The early identification of women with an increased risk of preeclampsia (PE) is desirable, but apart from soluble fms-like tyrosine kinase-1 (sFlt-1), few biomarkers have previously been identified as relevant for predicting preeclampsia. Since kinases and phosphatases regulate critical biological processes and previous evidence suggests a potential role of these molecules in preeclampsia, we performed this systematic review and metanalysis. The objective was to determine if there are kinases and phosphatases whose serum levels are different between women with and without PE, being relevant biomarkers of PE. We followed the recommendations of Cochrane and the Preferred Reported Items for Systematic Reviews and Metanalysis (PRISMA) to perform this study. The MESH terms preeclampsia, kinases, phosphatases, angiopoietins, soluble tyrosine protein kinase receptor (sTIE2), and cellular-mesenchymal-epithelial transition factor (c-MET) were combined to find relevant articles in the PubMed, PROSPERO, and Cochrane databases. Then, a qualitative and quantitative analysis was performed in R Studio software. From 580 abstracts identified, 37 were included in the final analysis, which comprised 24,211 pregnant women (2879 with PE and 21,332 women without PE [HP]. The pooled analysis showed that serum creatine kinase (CK) (SMD: 2.43, CI 95% 0.25-4.62) was significantly higher in PE, whereas sTIE2 and anti-angiogenic factor soluble c-Met (sMet)were significantly lower in PE than in HP (SMD: -0.23, CI95% -0.37 to -0.09; and SMD:0.24, CI95% 0.01-0.47, respectively). Adenosine monophosphate-activated protein kinase (AMPK), angiopoietin-1 (ANG-1), angiopoietin-2 (ANG-2), the ratio angiopoietin-1/angiopoietin-2, acid phosphatase, and alkaline phosphatase were not different between women with PE and HP. In summary CK, sTIE2, and c-MET are relevant biomarkers of PE. It is desirable to incorporate them into current models for PE prediction to evaluate their utility as biomarkers.

Oxygen Consumption and Heart Rate Responses in Different Vinyasa Yoga Sequences.

Yoga is widely practiced for its numerous health benefits, and it can also increase energy expenditure. Vinyasa yoga, a system of hatha yoga, meets criteria for moderate-intensity physical activity. It is unclear whether the individual sequences produce different oxygen consumption (VO2) and heart rate responses. The purpose of the present study was therefore to evaluate potential differences in VO2 and heart rate responses across sequences of a 60-minute vinyasa session. Participants included 40 healthy male (n = 20) and female (n = 20) adults (age 30.9 ± 8.8 y) with self-reported yoga experience. The sequence implemented was based on Baron Baptiste's Journey into Power sequence. This vinyasa yoga practice included several sequences: integration, sun salutation, crescent lunges, balancing, standing, back bending, and restorative. VO2 (mL/kg/min) was measured by portable indirect calorimetry and expressed as metabolic equivalents (MET). Heart rate was measured using a Polar HR monitor and presented as a percentage of age-predicted maximal heart rate (APMHR). METs and APMHR differed significantly across sequences (each p < 0.001). METs for the integration, sun-salutation, crescent-lunges, balancing, standing, back-bending, and restorative sequences were significantly different from one another (p < 0.001); balancing and back-bending sequences, however, were similar. During the integration and restorative sequences, APMHR was similar (p = 1.00) and significantly lower compared to sun-salutation, crescent-lunge, balancing, standing, and back-bending sequences (each p < 0.001). METs and APMHR differed significantly across sequences of a vinyasa yoga practice. These data could inform an individualized yoga series based on current fitness levels to maintain or improve cardiorespiratory fitness.

Correlation Analysis Between Clinical Hypermobility Measurement and Radiographic Parameters of the Hallux Valgus Deformity.

The finding of "hypermobility" has conventionally been considered as a dichotomous categorical variable in both clinical practice and in the literature. In other words, it is defined as being either "present" or "absent" in patients with hallux valgus. Yet it might be far more likely that this represents a continuous variable described by a bell-shaped distribution. Therefore the objective of this investigation was to consider hypermobility as a continuous variable, and to compare the sagittal plane first ray motion to radiographic parameters commonly used in the evaluation of the hallux valgus deformity by means of correlation analyses. The radiographs and measurements of 86 feet were included and measurement of sagittal plane first ray motion was performed with the validated Klaue device. No statistically significant correlation was observed between the total first ray motion with the first intermetatarsal angle (Pearson correlation coefficient 0.106; p = .333), hallux valgus angle (Pearson correlation coefficient -0.106; p = .330), nor sesamoid position (Pearson correlation coefficient 0.155; p = .157). The results of this investigation uniquely consider measurement of hypermobility as a continuous variable, and find no correlation between first ray sagittal plane motion and radiographic parameters associated with the hallux valgus deformity. These results might indicate that although the concept of hypermobility has traditionally been coupled with presentation of the hallux valgus deformity, this might simply represent the result of a historical confirmation bias.

The effect of brain-derived neurotrophic factor Val66Met polymorphism on adolescent activity and rest rhythms, circadian preferences and attentional performance.

BACKGROUND: Variations in circadian regulating mechanisms generate different individual preferences in respect of sleep and activity timing, which are known as chronotypes. In this sense, specifically during adolescence, there is a greater tendency for an eveningness chronotype. One factor that has been shown to have an impact on circadian rhythm patterns, as well as on some aspects of cognitive function, is the relatively common Val66Met (rs6265) polymorphism in the human brain-derived neurotrophic factor gene. OBJECTIVE: This study aimed to evaluate the effect of the BDNF Val66Met polymorphism on the performance of adolescents in attentional tests, circadian preferences and activity-rest rhythm. METHODS: 85 healthy high school students completed the Morningness-Eveningness Questionnaire to assess their circadian preferences; were evaluated using the Psychological Battery for Attention Assessment; and were categorized as carriers and non-carriers of the rs6265 polymorphism using the TaqMan rt-PCR technique. A subsample of 42 students had their activity/rest rhythm recorded by actigraphy for nine days from which sleep parameters were estimated. RESULTS: Circadian preference did not affect attentional performance (p > 0.1), but the time that the students attended school had an impact on all types of attention with morning shift students scoring higher, regardless of chronotype (p < 0.05). The presence of the BDNF Val66Met polymorphism was associated only with alternate attention performance (p < 0.05). Regarding actigraphy evaluation, the carriers of the polymorphism demonstrated significantly higher total time in bed, total sleep time, social jetlag, and earlier sleep onset. CONCLUSIONS: The results indicate some degree of adaptation in the students' attentional performance, according to their school schedules. The presence of BDNF polymorphism demonstrated a counterintuitive impact on attentional performance, comparing to previous findings. The findings reinforce the effect of genetic traits on sleep-wake rhythm parameters, when objectively evaluated.

BDNF rs6265 differentially influences neurometabolites in the anterior cingulate of healthy and bipolar disorder subjects.

Brain-derived neurotrophic factor (BDNF) is the most abundant brain neurotrophin and plays a critical role in neuronal growth, survival and plasticity, implicated in the pathophysiology of Bipolar Disorders (BD). The single-nucleotide polymorphism in the BDNF gene (BDNF rs6265) has been associated with decreased hippocampal BDNF secretion and volume in met carriers in different populations, although the val allele has been reported to be more frequent in BD patients. The anterior cingulate cortex (ACC) is a key center integrating cognitive and affective neuronal connections, where consistent alterations in brain metabolites such as Glx (Glutamate + Glutamine) and N-acetylaspartate (NAA) have been consistently reported in BD. However, little is known about the influence of BDNF rs6265 on neurochemical profile in the ACC of Healthy Controls (HC) and BD subjects. The aim of this study was to assess the influence of BDNF rs6265 on ACC neurometabolites (Glx, NAA and total creatine- Cr) in 124 euthymic BD type I patients and 76 HC, who were genotyped for BDNF rs6265 and underwent a 3-Tesla proton magnetic resonance imaging and spectroscopy scan (1 H-MRS) using a PRESS ACC single-voxel (8cm3) sequence. BDNF rs6265 polymorphism showed a significant two-way interaction (diagnosis × genotype) in relation to NAA/Cr and total Cr. While met carriers presented increased NAA/Cr in HC, BD-I subjects with the val allele revealed higher total Cr, denoting an enhanced ACC metabolism likely associated with increased glutamatergic metabolites observed in BD-I val carriers. However, these results were replicated only in men. Therefore, our results support evidences that the BDNF rs6265 polymorphism exerts a complex pleiotropic effect on ACC metabolites influenced by the diagnosis and sex.

Blocking the HGF-MET pathway induces resolution of neutrophilic inflammation by promoting neutrophil apoptosis and efferocytosis.

Inflammation resolution is an active process that involves cellular events such as apoptosis and efferocytosis, which are key steps in the restoration of tissue homeostasis. Hepatocyte growth factor (HGF) is a growth factor mostly produced by mesenchymal-origin cells and has been described to act via MET receptor tyrosine kinase. The HGF/MET axis is essential for determining the progression and severity of inflammatory and immune-mediated disorders. Here, we investigated the effect of blocking the HGF/MET signalling pathway by PF-04217903 on the resolution of established models of neutrophilic inflammation. In a self-resolving model of gout induced by MSU crystals, HGF expression on periarticular tissue peaked at 12 h, the same time point that neutrophils reach their maximal accumulation in the joints. The HGF/MET axis was activated in this model, as demonstrated by increased levels of MET phosphorylation in neutrophils (Ly6G+ cells). In addition, the number of neutrophils was reduced in the knee exudate after PF-04217903 treatment, an effect accompanied by increased neutrophil apoptosis and efferocytosis and enhanced expression of Annexin A1, a key molecule for inflammation resolution. Reduced MPO activity, IL-1ß and CXCL1 levels were also observed in periarticular tissue. Importantly, PF-04217903 reduced the histopathological score and hypernociceptive response. Similar findings were obtained in LPS-induced neutrophilic pleurisy. In human neutrophils, the combined use of LPS and HGF increased MET phosphorylation and provided a prosurvival signal, whereas blocking MET with PF-04217903 induced caspase-dependent neutrophil apoptosis. Taken together, these data demonstrate that blocking HGF/MET signalling may be a potential therapeutic strategy for inducing the resolution of neutrophilic inflammatory responses.

Involvement of Met receptor pathway in aggressive behavior of colorectal cancer cells induced by parathyroid hormone-related peptide.

BACKGROUND: Parathyroid hormone-related peptide (PTHrP) plays a key role in the development and progression of many tumors. We found that in colorectal cancer (CRC) HCT116 cells, the binding of PTHrP to its receptor PTHR type 1 (PTHR1) activates events associated with an aggressive phenotype. In HCT116 cell xenografts, PTHrP modulates the expression of molecular markers linked to tumor progression. Empirical evidence suggests that the Met receptor is involved in the development and evolution of CRC. Based on these data, we hypothesized that the signaling pathway trigged by PTHrP could be involved in the transactivation of Met and consequently in the aggressive behavior of CRC cells. AIM: To elucidate the relationship among PTHR1, PTHrP, and Met in CRC models. METHODS: For in vitro assays, HCT116 and Caco-2 cells derived from human CRC were incubated in the absence or presence of PTHrP (1-34) (10-8 M). Where indicated, cells were pre-incubated with specific kinase inhibitors or dimethylsulfoxide, the vehicle of the inhibitors. The protein levels were evaluated by Western blot technique. Real-time polymerase chain reaction (RT-qPCR) was carried out to determine the changes in gene expression. Wound healing assay and morphological monitoring were performed to evaluate cell migration and changes related to the epithelial-mesenchymal transition (EMT), respectively. The number of viable HCT116 cells was counted by trypan blue dye exclusion test to evaluate the effects of irinotecan (CPT-11), oxaliplatin (OXA), or doxorubicin (DOXO) with or without PTHrP. For in vivo tests, HCT116 cell xenografts on 6-wk-old male N:NIH (S)_nu mice received daily intratumoral injections of PTHrP (40 µg/kg) in 100 µL phosphate-buffered saline (PBS) or the vehicle (PBS) as a control during 20 d. Humanitarian slaughter was carried out and the tumors were removed, weighed, and fixed in a 4% formaldehyde solution for subsequent treatment by immunoassays. To evaluate the expression of molecular markers in human tumor samples, we studied 23 specimens obtained from CRC patients which were treated at the Hospital Interzonal de Graves y Agudos Dr. José Penna (Bahía Blanca, Buenos Aires, Argentina) and the Hospital Provincial de Neuquén (Neuquén, Neuquén, Argentina) from January 1990 to December 2007. Seven cases with normal colorectal tissues were assigned to the control group. Tumor tissue samples and clinical histories of patients were analyzed. Paraffin-embedded blocks from primary tumors were reviewed by hematoxylin-eosin staining technique; subsequently, representative histological samples were selected from each patient. From each paraffin block, tumor sections were stained for immunohistochemical detection. The statistical significance of differences was analyzed using proper statistical analysis. The results were considered statistically significant at P < 0.05. RESULTS: By Western blot analysis and using total Met antibody, we found that PTHrP regulated Met expression in HCT116 cells but not in Caco-2 cells. In HCT116 cells, Met protein levels increased at 30 min (P < 0.01) and at 20 h (P < 0.01) whereas the levels diminished at 3 min (P < 0.05), 10 min (P < 0.01), and 1 h to 5 h (P < 0.01) of PTHrP treatment. Using an active Met antibody, we found that where the protein levels of total Met decreased (3 min, 10 min, and 60 min of PTHrP exposure), the status of phosphorylated/activated Met increased (P < 0.01) at the same time, suggesting that Met undergoes proteasomal degradation after its phosphorylation/activation by PTHrP. The increment of its protein level after these decreases (at 30 min and 20 h) suggests a modulation of Met expression by PTHrP in order to improve Met levels and this idea is supported by our observation that the cytokine increased Met mRNA levels at least at 15 min in HCT116 cells as revealed by RT-qPCR analysis (P < 0.05). We then proceeded to evaluate the signaling pathways that mediate the phosphorylation/ activation of Met induced by PTHrP in HCT116 cells. By Western blot technique, we observed that PP1, a specific inhibitor of the activation of the proto-oncogene protein tyrosine kinase Src, blocked the effect of PTHrP on Met phosphorylation (P < 0.05). Furthermore, the selective inhibition of the ERK 1/2 mitogen-activated protein kinase (ERK 1/2 MAPK) using PD98059 and the p38 MAPK using SB203580 diminished the effect of PTHrP on Met phosphorylation/activation (P < 0.05). Using SU11274, the specific inhibitor of Met activation, and trypan blue dye exclusion test, Western blot, wound healing assay, and morphological analysis with a microscope, we observed the reversal of cell events induced by PTHrP such as cell proliferation (P < 0.05), migration (P < 0.05), and the EMT program (P < 0.01) in HCT116 cells. Also, PTHrP favored the chemoresistance to CPT-11 (P < 0.001), OXA (P < 0.01), and DOXO (P < 0.01) through the Met pathway. Taken together, these findings suggest that Met activated by PTHrP participates in events associated with the aggressive phenotype of CRC cells. By immunohistochemical analysis, we found that PTHrP in HCT116 cell xenografts enhanced the protein expression of Met (0.190 ± 0.014) compared to tumors from control mice (0.110 ± 0.012; P < 0.05) and of its own receptor (2.27 ± 0.20) compared to tumors from control mice (1.98 ± 0.14; P < 0.01). Finally, assuming that the changes in the expression of PTHrP and its receptor are directly correlated, we investigated the expression of both Met and PTHR1 in biopsies of CRC patients by immunohistochemical analysis. Comparing histologically differentiated tumors with respect to those less differentiated, we found that the labeling intensity for Met and PTHR1 increased and diminished in a gradual manner, respectively (P < 0.05). CONCLUSION: PTHrP acts through the Met pathway in CRC cells and regulates Met expression in a CRC animal model. More basic and clinical studies are needed to further evaluate the PTHrP/Met relationship.

Oncogene Overlap Analysis of Circulating Cell-free Tumor DNA to Explore the Appropriate Criteria for Defining MET Copy Number-Driven Lung Cancer.

INTRODUCTION: Defining clinically relevant MET amplification levels in non-small cell lung cancer (NSCLC) remains challenging. We hypothesize that oncogene overlap and MET amplicon size decline with increase in MET plasma copy number (pCN), thus enriching for MET-dependent states. PATIENTS AND METHODS: We interrogated cell-free DNA NGS results of 16,782 patients with newly diagnosed advanced NSCLC to identify those with MET amplification as reported using Guardant360. Co-occurring genomic mutations and copy number alterations within each sample were evaluated. An exploratory method of adjusting for tumor fraction was also performed and amplicon size for MET was analyzed when available. RESULTS: MET amplification was detected in 207 (1.2%) of samples. pCN ranged from 2.1 to 52.9. Of these, 43 (20.8%) had an overlapping oncogenic driver, including 23 (11.1%) METex14 skipping or other MET mutations. The degree of (non-MET) oncogene overlap decreased with increases in pCN. Patients with MET pCN ≥ 2.7 had lower rates of overlapping drivers compared to those with MET pCN < 2.7 (6.1% vs. 16.3%, P = .033). None of the 7 patients with pCN > 6.7 had an overlapping driver. After adjusting for tumor fraction, adjusted pCN (ApCN) was also lower for those with overlapping drivers than those without (median ApCN 4.9 vs. 7.3, P =.024). There was an inverse relationship between amplicon size and pCN. CONCLUSIONS: We propose that a high MET pCN and/or ApCN, together with the absence of overlapping oncogenic drivers and small MET amplicon size, will enrich for patients most likely to derive benefit from MET targeted therapy.

MEK inhibitor sensitivity in BRAF fusion-driven prostate cancer.

PURPOSE: The identification of subpopulations harboring druggable targets has become a major step forward in the subclassification of solid tumors into small groups suitable for specific therapies. BRAF fusions represent a paradigm of uncommon and targetable oncogenic events and have been widely correlated to the development of specific malignancies. However, they are only present in a limited frequency across most common tumor types. At this regard, we performed a genomic screening aimed to identifying rare variants associated to advanced prostate cancer development. METHODS: Tumoral tissue genomic screening of 41 patients developing advanced prostate cancer was performed at our center as part of the GETHI XX study. The project, sponsored by the Spanish Collaborative Group in Rare Cancers (GETHI), aims to analyze the molecular background of rare tumors and to discover unfrequent molecular variants in common tumors. RESULTS: Here we present the clinical outcome and an in-deep molecular analysis performed in a case harboring a SND1-BRAF fusion gene. The identification of such rearrangement in a patient refractory to standard therapies led to the administration of trametinib (MEK inhibitor). Despite unsensitive to standard therapies, the patient achieved a dramatic response to trametinib. A comprehensive study of the tumor demonstrated this event to be a trunk alteration with higher expression of MEK in areas of tumor invasion. CONCLUSIONS: Our study describes the patient-driven discovery of the first BRAF fusion-driven prostate cancer effectively treated with trametinib. Consequently, MAPK pathway activation could define a new subtype of prostate cancer susceptible to a tailored management.

Non-small-cell lung cancer: how to manage MET exon 14 skipping mutant disease.

Several oncogenic mechanisms have been identified for MET, including MET amplification, fusions, mutations in the tyrosine kinase domain and exon 14 skipping alterations. MET exon 14 mutations are found in about 3-5% of non-small-cell lung cancers. Dysregulation of the MET receptor leads to cell proliferation and survival by activation of the PI3K-AKT-TOR and RAS-RAF-MET-ERK canonical pathways. Targeting the MET tyrosine kinase domain in the setting of MET exon 14 mutations using effective MET tyrosine kinase inhibitors is a current targeted therapy option for patients with metastatic lung cancer. In this Review, we focus on the management of patients with MET exon 14 skipping alterations by addressing the biology of the MET receptor and exon 14 skipping mutations, current treatment strategies, and sequential treatment options based on resistance mechanisms to MET inhibitors in patients with non-small-cell lung cancer.

GM2/GM3 controls the organizational status of CD82/Met microdomains: further studies in GM2/GM3 complexation.

At cell surface gangliosides might associate with signal transducers proteins, grown factor receptors, integrins, small G-proteins and tetraspanins establishing microdomains, which play important role in cell adhesion, cell activation, motility, and growth. Previously, we reported that GM2 and GM3 form a heterodimer that interacts with the tetraspanin CD82, controlling epithelial cell mobility by inhibiting integrin-hepatocyte growth factor-induced cMet tyrosine kinase signaling. By using molecular dynamics simulations to study the molecular basis of GM2/GM3 interaction we demonstrate, here, that intracellular levels of Ca2+ mediate GM2/GM3 complexation via electrostatic interaction with their carboxyl groups, while hydrogen bonds between the ceramide groups likely aid stabilizing the complex. The presence of GM2/GM3 complex alters localization of CD82 on cell surface and therefore downstream signalization. These data contribute for the knowledge of how glycosylation may control signal transduction and phenotypic changes.