logo
    Abstract:
    Central conducting lymphatic anomaly (CCLA) due to congenital maldevelopment of the lymphatics can result in debilitating and life-threatening disease with limited treatment options. We identified 4 individuals with CCLA, lymphedema, and microcystic lymphatic malformation due to pathogenic, mosaic variants in KRAS. To determine the functional impact of these variants and identify a targeted therapy for these individuals, we used primary human dermal lymphatic endothelial cells (HDLECs) and zebrafish larvae to model the lymphatic dysplasia. Expression of the p.Gly12Asp and p.Gly13Asp variants in HDLECs in a 2‑dimensional (2D) model and 3D organoid model led to increased ERK phosphorylation, demonstrating these variants activate the RAS/MAPK pathway. Expression of activating KRAS variants in the venous and lymphatic endothelium in zebrafish resulted in lymphatic dysplasia and edema similar to the individuals in the study. Treatment with MEK inhibition significantly reduced the phenotypes in both the organoid and the zebrafish model systems. In conclusion, we present the molecular characterization of the observed lymphatic anomalies due to pathogenic, somatic, activating KRAS variants in humans. Our preclinical studies suggest that MEK inhibition should be studied in future clinical trials for CCLA due to activating KRAS pathogenic variants.
    Keywords:
    Noonan Syndrome
    ABSTRACT: Chronic edema can be debilitating in Noonan's syndrome. Transient childhood lymnphedema may be followed by elephantiasis as early as adolescence. Recurrent streptococcal cellulitis exacerbates this problem. Hygenic measures and prophylactic antiobiotic therapy may slow progression of lymphedema of the legs in Noonan's syndrome.
    Noonan Syndrome
    Elephantiasis
    Cellulite
    e19324 Background: KRAS G12C mutations are present in 15% of non-small cell lung cancer (NSCLC) and have recently been shown to confer sensitivity to KRAS(G12C) inhibitors. This study aims to assess the clinical features and outcomes with KRAS G12C mutant NSCLC in a real-world setting. Methods: Patients enrolled in an Australian prospective cohort study, Thoracic Malignancies Cohort (TMC), between July 2012 to October 2019 with metastatic or recurrent non-squamous NSCLC, with available KRAS test results, and without EGFR, ALK, or ROS1 gene aberrations, were selected. Data was extracted from TMC and patient records. Clinicopathologic features, treatment and overall survival was compared for KRAS wildtype ( KRAS WT ) and KRAS mutated ( KRAS mut ) patients, and between KRAS G12C ( KRAS G12C ) and other ( KRAS other ) mutations. Results: Of 1386 patients with non squamous NSCLC, 1040 were excluded for: non metastatic or recurrent (526); KRAS not tested (356); ALK, EGFR or ROS1 positive (154); duplicate (4). Of 346 patients analysed, 202 (58%) were KRAS WT and 144 (42%) were KRAS mut , of whom 65 (45%) were KRAS G12C . 100% of pts with KRAS G12C were smokers, compared to 92% of KRAS other and 83% of KRAS WT . The prevalence of brain metastases over entire follow-up period was similar between KRAS mut and KRAS WT (33% vs 40%, p = 0.17), and KRAS G12C and KRAS other (40% vs 41%, p = 0.74). Likewise, there was no difference in the proportion of patients receiving one or multiple lines of systemic therapy. Overall survival (OS) was also similar between KRAS mut and KRAS WT (p = 0.54), and KRAS G12C and KRAS other (p = 0.39). Conclusions: In this real-world prospective cohort, patients had comparable clinical features regardless of having a KRAS mut , KRAS G12C or KRAS other mutation, or being KRAS WT . Treatment and survival were also similar between groups. While not prognostic, KRAS G12C may be an important predictive biomarker as promising KRAS G12C covalent inhibitors continue to be developed.
    RASopathies - group of inherited diseases, caused by mutations in genes, encoding components or regulators of the Ras/mitogen-activated protein kinase (MAPK) pathway. We identified 28 patients with inherited diseases from RASopathies: 61% - with Noonan syndrome, 14 % - with Cardiofaciocutaneous syndrome, 14% - with Costello syndrome - 11% - Noonan syndrome-like with loose anagen hair. Mutation c.770C>T, p.S257L in RAF1gene is most common in hypertrophic cardiomyopathy patients with Noonan syndrome. All patients with Noonan syndrome-like with loose anagen hair have mutation c.4A>G , p.S2G in SHOC2 gene.
    Noonan Syndrome
    Costello syndrome
    PTPN11
    Citations (0)
    Abstract Background : KRAS is the most frequently mutated oncogene in cancer, however efforts to develop targeted therapies have been largely unsuccessful. Recently, two small-molecule inhibitors, AMG 510 and MRTX849, have shown promising activity in KRAS G12C-mutant solid tumors. The current study aims to assess the molecular profile of KRAS G12C in colorectal (CRC) and non-small-cell lung cancer (NSCLC) tested in a clinical certified laboratory. Methods : CRC and NSCLC samples submitted for KRAS testing between 2017 and 2019 were reviewed. CRC samples were tested for KRAS and NRAS by pyrosequencing, while NSCLC samples were submitted to next generation sequencing of KRAS, NRAS, EGFR, and BRAF. Results : The dataset comprised 4,897 CRC and 4,686 NSCLC samples. Among CRC samples, KRAS was mutated in 2,354 (48.1%). Most frequent codon 12 mutations were G12D in 731 samples (15.2%) and G12V in 462 (9.6%), followed by G12C in 167 (3.4%). KRAS mutations were more frequent in females than males (p=0.003), however this difference was exclusive of non-G12C mutants (p<0.001). KRAS mutation frequency was lower in the South and North regions (p=0.003), but again KRAS G12C did not differ significantly (p=0.80). In NSCLC, KRAS mutations were found in 1,004 samples (21.4%). As opposed to CRC samples, G12C was the most common mutation in KRAS, in 346 cases (7.4%). The frequency of KRAS G12C was higher in the South and Southeast regions (p=0.012), and lower in patients younger than 50 years (p<0.001). KRAS G12C mutations were largely mutually exclusive with other driver mutations; only 11 NSCLC (3.2%) and 3 CRC (1.8%) cases had relevant co-mutations. Conclusions : KRAS G12C presents in frequencies higher than several other driver mutations, represent a large volume of patients in absolute numbers. KRAS testing should be considered in all CRC and NSCLC patients, independently of clinical or demographic characteristics.
    Pyrosequencing
    RAS-патии - группа наследственных заболеваний, возникающая вследствие нарушения регуляции функции RAS/MAPK внутриклеточных путей (Ras/mitogen-activated protein kinase). Суммарная частота заболеваний данной группы - 1 случай на 1000 новорожденных. Наиболее часто среди RAS-патий встречается синдром Нунан. В настоящее время описано 13 генов, мутации которых отвечают за развитие данного заболевания, включая ген SHOC2, ассоциированный с Нунан-подобным синдромом и измененной структурой волос (Noonan-like syndrome with loose anagen hair) и ген LZTR1, мутации в котором приводят к развитию синдрома Нунан, тип 2 с аутосомно-рецессивным типом наследования. RASopathies - group of inherited diseases, caused by mutations in genes, encoding components or regulators of the Ras/mitogen-activated protein kinase (MAPK) pathway. We identified 28 patients with inherited diseases from RASopathies: 61% - with Noonan syndrome, 14 % - with Cardiofaciocutaneous syndrome, 14% - with Costello syndrome - 11% - Noonan syndrome-like with loose anagen hair. Mutation c.770C>T, p.S257L in RAF1gene is most common in hypertrophic cardiomyopathy patients with Noonan syndrome. All patients with Noonan syndrome-like with loose anagen hair have mutation c.4A>G , p.S2G in SHOC2 gene.
    Noonan Syndrome
    Costello syndrome
    PTPN11
    Abstract Although KRAS is the most commonly mutated oncogene in human cancer, no effective therapies exist for KRAS mutant cancers. Attempts to target KRAS directly or to target single effector pathways downstream of KRAS have met limited success. Previously, our laboratory and others showed that simultaneous targeting of more than one KRAS effector pathway, specifically the MEK-ERK and PI3K-AKT pathways, can cause dramatic responses in KRAS-driven genetically-engineered mouse tumor models. These findings support the promise of targeted therapy combinations for KRAS mutant cancers and have led to clinical trials evaluating combined PI3K/MEK inhibition. We evaluated the efficacy of combined PI3K/MEK inhibition in a panel of 30 KRAS mutant cell lines. Roughly half of all cell lines showed limited sensitivity to this combination, suggesting that combined PI3K/MEK inhibition may only be effective in a subset of KRAS mutant cancers and underscoring the need for additional combination therapy strategies. To develop new targeted therapy combinations for KRAS mutant cancers, we designed a pooled shRNA-drug screen strategy aimed at rapidly identifying genes that, when inhibited, synergize with MEK inhibitors to decrease the viability of KRAS mutant cancer cells. Using this approach, we identified the anti-apoptotic protein BCLXL as a potential target for combination therapy with MEK inhibitors. When tested in vitro against a panel of 30 KRAS mutant cell lines, simultaneous pharmacologic inhibition of BCLXL (using the BH3 mimetic ABT-263) and MEK led to pronounced apoptosis and reduced viability in most cell lines, including many cell lines that were insensitive to combined PI3K/MEK inhibition. In vivo, the combination of ABT-263 and a MEK inhibitor led to marked tumor regressions in KRAS mutant xenograft models and to dramatic and sustained tumor regressions (&gt;70% reduction in tumor size) in a KRAS-driven genetically-engineered mouse model of lung cancer. These findings suggest that combined inhibition of BCLXL and MEK is a promising targeted therapy combination for potential evaluation in clinical trials for patients with KRAS mutant cancers. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 875. doi:1538-7445.AM2012-875
    Trametinib
    Targeted Therapy
    <i>Background:</i> The autosomal-dominant Noonan syndrome (MIM 163950) is characterized by short stature, typical facial dysmorphology and heart defects. Noonan syndrome is genetically heterogeneous. Over the last few years, germline mutations in four genes have been found in people with clinical signs of Noonan syndrome, accounting for approximately 65% of cases. All four genes encode proteins involved in the Ras–mitogen-activated protein kinase pathway and result in upregulation of this pathway. Recently, more data on final height after long-term growth hormone (GH) therapy has become available that shows its effectiveness in increasing final height for individuals with Noonan syndrome. <i>Conclusions:</i> The genetics underlying Noonan syndrome has been partially clarified over the last 5 years and further findings will undoubtedly be reported in the next few years. GH therapy has been used to treat patients with Noonan syndrome for approximately 15 years and is effective in improving adult height in affected children.
    Noonan Syndrome
    PTPN11
    Citations (14)