Bardet-Biedl syndrome (BBS) is a pleiotropic ciliopathy caused by dysfunction of the BBSome, a cargo adaptor essential for export of transmembrane receptors from cilia. Although actin-dependent ectocytosis has been proposed to compensate defective cargo retrieval, its molecular basis remains unclear, especially in relation to BBS pathology. In this study, we investigated how actin polymerization and ectocytosis are regulated within the cilium. Our findings reveal that ciliary CDC42, a RHO-family GTPase triggers in situ actin polymerization, ciliary ectocytosis, and cilia shortening in BBSome-deficient cells. Activation of the Sonic Hedgehog pathway further enhances CDC42 activity specifically in BBSome-deficient cilia. Inhibition of CDC42 in BBSome-deficient cells decreases the frequency and duration of ciliary actin polymerization events, causing buildup of G protein coupled receptor 161 (GPR161) in bulges along the axoneme during Sonic Hedgehog signaling. Overall, our study identifies CDC42 as a key trigger of ciliary ectocytosis. Hyperactive ciliary CDC42 and ectocytosis and the resulting loss of ciliary material might contribute to BBS disease severity.

• MeSH
• aktiny * metabolismus   MeSH
• Bardetův-Biedlův syndrom metabolismus   genetika   patologie   MeSH
• cdc42 protein vázající GTP * metabolismus   genetika   MeSH
• cilie * metabolismus   MeSH
• lidé MeSH
• myši MeSH
• proteiny hedgehog * metabolismus   MeSH
• receptory spřažené s G-proteiny metabolismus   genetika   MeSH
• signální transdukce * MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Emerging evidence suggests that tumour morphological heterogeneity may influence mutational profiles relevant to therapy response. In this pilot study, we aimed to assess whether mutations identified within specific morphological patterns or at the invasion front correlate with shorter time to progression after anti-EGFR therapy, as compared to whole-tissue analysis. METHODS: We investigated genetic mutations in 142 samples from primary tumours of 39 KRAS wild-type metastatic colorectal cancer (CRC) patients receiving anti-EGFR therapy. Deep next-generation sequencing was performed on whole-tumour sections and six morphology-defined tumour regions. RESULTS: Mutations in genes linked to anti-EGFR therapy response (KRAS, BRAF, NRAS, PTEN and PI3KCA) were found uniquely in the non-responder group, with substantial variability across morphological sub-regions. BRAF mutations were aligned with serrated and mucinous morphologies, while KRAS mutations (p.Lys147Glu and p.Ala146Thr) were associated with mucinous and desmoplastic morphologies. In all cases, the cumulative mutational profile from sub-regions provided more details than that of the whole-tumour profile. CONCLUSION: Our findings highlight that comprehensive analysis, considering morphological heterogeneity, is crucial for personalised CRC treatment strategies.

• MeSH
• chemorezistence * genetika   MeSH
• dospělí MeSH
• erbB receptory antagonisté a inhibitory   MeSH
• fosfohydroláza PTEN genetika   MeSH
• GTP-fosfohydrolasy genetika   MeSH
• inhibitory proteinkinas * terapeutické užití   MeSH
• kolorektální nádory * genetika   farmakoterapie   patologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mutace * MeSH
• mutační analýza DNA MeSH
• pilotní projekty MeSH
• protinádorové látky * terapeutické užití   MeSH
• protoonkogenní proteiny B-Raf genetika   MeSH
• protoonkogenní proteiny p21(ras) genetika   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• vysoce účinné nukleotidové sekvenování MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Syncytin-1 and Syncytin-2 are envelope glycoproteins encoded by human endogenous retroviruses that have been exapted for the fusion of cytotrophoblast cells into syncytiotrophoblasts during placental development. Pregnancy complications like preeclampsia are associated with altered expression of interferon-stimulated genes, including guanylate-binding protein 5 (GBP5). Here, we show that misdirected antiviral activity of GBP5 impairs processing and activation of Syncytin-1. In contrast, the proteolytic activation of Syncytin-2 is not affected by GBP5, and its fusogenic activity is only modestly reduced. Mechanistic analyses revealed that Syncytin-1 is mainly cleaved by the GBP5 target furin, whereas Syncytin-2 is also efficiently processed by the proprotein convertase subtilisin/kexin type 7 (PCSK7) and thus resistant to GBP5-mediated restriction. Mutational analyses mapped PCSK7 processing of Syncytin-2 to a leucine residue upstream of the polybasic cleavage site. In summary, we identified an innate immune mechanism that impairs the activity of a co-opted endogenous retroviral envelope protein during pregnancy and may potentially contribute to the pathogenesis of pregnancy disorders.

• MeSH
• furin metabolismus   MeSH
• fúze buněk MeSH
• genové produkty env metabolismus   genetika   MeSH
• lidé MeSH
• placenta * metabolismus   cytologie   MeSH
• proteiny vázající GTP * metabolismus   genetika   MeSH
• těhotenské proteiny * metabolismus   genetika   MeSH
• těhotenství MeSH
• trofoblasty * metabolismus   cytologie   MeSH
• Check Tag
• lidé MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Previous research indicated that the cytotoxic activity of the antitumor platinum(II) complex [Pt(1S,2S-diaminocyclohexane)(5,6-dimethyl-1,10-phenanthroline)]2+ (56MESS) was not primarily attributed to DNA binding, despite the complex being confirmed to localize also in the nucleus. In this study, we have demonstrated that the antiproliferative activity of 56MESS indeed involves DNA binding. Furthermore, in addition to binding duplex DNA, the complex also interacts with non-canonical secondary DNA structures, such as G-quadruplexes (G4s) and i-Motifs (iMs). This interaction leads to the suppression of G-regulated oncogene expression and disrupts key enzymatic processes associated with DNA, potentially contributing to DNA damage and the biological activity of 56MESS. These findings build upon previously published results, revealing that the anticancer activity of 56MESS is significantly more multifaceted than previously understood, involving multiple distinct mechanisms.

• MeSH
• DNA metabolismus   chemie   MeSH
• down regulace * účinky léků   MeSH
• G-kvadruplexy * účinky léků   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• organoplatinové sloučeniny * farmakologie   chemie   MeSH
• poškození DNA * účinky léků   MeSH
• proliferace buněk účinky léků   MeSH
• protinádorové látky * farmakologie   chemie   MeSH
• protoonkogenní proteiny c-myc * genetika   metabolismus   MeSH
• protoonkogenní proteiny p21(ras) * genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Targeting RAS mutant (MT) colorectal cancer (CRC) remains a difficult challenge, mainly due to the pervasiveness of RAS/MEK-mediated feedback loops. Preclinical studies identified MET/STAT3 as an important mediator of resistance to KRAS-MEK1/2 blockade in RASMT CRC. This dose escalation/expansion study assessed safety and initial efficacy of the MEK1/2 inhibitor binimetinib with MET inhibitor crizotinib in RASMT advanced CRC patients. METHODS: In the dose escalation phase, patients with advanced solid tumours received binimetinib with crizotinib, using a rolling- 6 design to determine the maximum tolerable dose (MTD) and safety/tolerability. A subsequent dose expansion in RASMT CRC patients assessed treatment response. Blood samples for pharmacokinetics, MET biomarker and ctDNA analyses, and skin/tumour biopsies for pharmacodynamics, c-MET immunohistochemistry (IHC), MET in situ hybridisation (ISH) and MET DNA-ISH analyses were collected. RESULTS: Twenty patients were recruited in 3 cohorts in the dose escalation. The MTD was binimetinib 30 mg B.D, days 1-21 every 28 days, with crizotinib 250 mg O.D continuously. Dose-limiting toxicities included grade ≥ 3 transaminitis, creatinine phosphokinase increases and fatigue. Thirty-six RASMT metastatic CRC patients were enrolled in the dose expansion. Pharmacokinetic and pharmacodynamic parameters showed evidence of target engagement. Across the entire study, the most frequent treatment-related adverse events (TR-AE) were rash (80.4%), fatigue (53.4%) and diarrhoea (51.8%) with grade ≥ 3 TR-AE occurring in 44.6%. Best clinical response within the RASMT CRC cohort was stable disease in seven patients (24%). Tumour MET super-expression (IHC H-score > 180 and MET ISH + 3) was observed in 7 patients (24.1%), with MET-amplification only present in 1 of these patients. This patient discontinued treatment early during cycle 1 due to toxicity. Patients with high baseline RASMT allele frequency had a significant shorter median overall survival compared with that seen for patients with low baseline KRASMT allele frequency. CONCLUSIONS: Combination binimetinib/crizotinib showed a poor tolerability with no objective responses observed in RASMT advanced CRC patients. EudraCT-Number: 2014-000463 - 40 (20/06/2014: A Sequential Phase I study of MEK1/2 inhibitors PD- 0325901 or Binimetinib combined with cMET inhibitor Crizotinib in RAS Mutant and RAS Wild Type with aberrant c-MET).

• MeSH
• benzimidazoly * aplikace a dávkování   škodlivé účinky   farmakokinetika   MeSH
• dospělí MeSH
• inhibitory proteinkinas aplikace a dávkování   škodlivé účinky   MeSH
• kolorektální nádory * farmakoterapie   genetika   patologie   MeSH
• krizotinib * aplikace a dávkování   škodlivé účinky   MeSH
• lidé středního věku MeSH
• lidé MeSH
• MAP kinasa-kinasa 1 antagonisté a inhibitory   MeSH
• MAP kinasa-kinasa 2 antagonisté a inhibitory   MeSH
• maximální tolerovaná dávka MeSH
• mutace MeSH
• protokoly protinádorové kombinované chemoterapie * terapeutické užití   škodlivé účinky   farmakokinetika   aplikace a dávkování   MeSH
• protoonkogenní proteiny c-met antagonisté a inhibitory   genetika   MeSH
• Ras proteiny genetika   MeSH
• senioři MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• klinické zkoušky, fáze I MeSH

Metastatický kolorektální karcinom je heterogenní onemocnění, kde je léčba individuálně volena dle znalosti molekulárních vlastností nádoru. S přibývajícími poznatky o molekulární biologii onemocnění roste současně počet potenciálních cílů pro specifickou terapii. V posledních letech je novou možností pro pacienty s metastatickým kolorektálním karcinomem s prokázanou KRAS G12C mutací terapie KRAS G12C inhibitory. Cílem článku je poskytnout přehled současných možností léčby této jednotky.

Metastatic colorectal cancer is a heterogeneous disease where treatment is individually selected according to the knowledge of the molecular characteristics of the tumour. As the knowledge of the molecular biology of the disease increases, the number of potential targets for specific therapies increases. In recent years, KRAS G12C inhibitor therapy has become a new treatment option for patients with metastatic colorectal cancer with a proven KRAS G12C mutation. The aim of this article is to provide an overview of current treatment options for this entity.

• Klíčová slova
• KRAS G12C,
• MeSH
• erbB receptory antagonisté a inhibitory   MeSH
• klinická studie jako téma MeSH
• klinické zkoušky jako téma MeSH
• kolorektální nádory * farmakoterapie   MeSH
• kombinovaná farmakoterapie metody   MeSH
• lidé MeSH
• mutace MeSH
• piperaziny aplikace a dávkování   MeSH
• protinádorové látky aplikace a dávkování   MeSH
• pyrimidiny aplikace a dávkování   MeSH
• Ras proteiny antagonisté a inhibitory   genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• přehledy MeSH

The eIF4F translation initiation complex plays a critical role in melanoma resistance to clinical BRAF and MEK inhibitors. In this study, we uncover a function of eIF4F in the negative regulation of the rat sarcoma (RAS)/rapidly accelerated fibrosarcoma (RAF)/mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK) signaling pathway. We demonstrate that eIF4F is essential for controlling ERK signaling intensity in treatment-naïve melanoma cells harboring BRAF or NRAS mutations. Specifically, the dual-specificity phosphatase DUSP6/MKP3, which acts as a negative feedback regulator of ERK activity, requires continuous production in an eIF4F-dependent manner to limit excessive ERK signaling driven by oncogenic RAF/RAS mutations. Treatment with small-molecule eIF4F inhibitors disrupts the negative feedback control of MAPK signaling, leading to ERK hyperactivation and EGR1 overexpression in melanoma cells in vitro and in vivo. Furthermore, our quantitative analyses reveal a high spare signaling capacity in the ERK pathway, suggesting that eIF4F-dependent feedback keeps the majority of ERK molecules inactive under normal conditions. Overall, our findings highlight the crucial role of eIF4F in regulating ERK signaling flux and suggest that pharmacological eIF4F inhibitors can disrupt the negative feedback control of MAPK activity in melanomas with BRAF and NRAS activating mutations.

• MeSH
• eukaryotický iniciační faktor 4F * metabolismus   genetika   MeSH
• extracelulárním signálem regulované MAP kinasy metabolismus   MeSH
• fosfatasa 6 s dvojí specificitou metabolismus   genetika   MeSH
• GTP-fosfohydrolasy * metabolismus   genetika   MeSH
• lidé MeSH
• MAP kinasový signální systém * genetika   MeSH
• melanom * genetika   metabolismus   patologie   MeSH
• membránové proteiny * metabolismus   genetika   MeSH
• mutace * MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• protoonkogenní proteiny B-Raf * genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Background/Objectives: Although the overall survival prognosis of patients in advanced stages of pancreatic ductal adenocarcinoma (PDAC) is poor, typically ranging from days to months from diagnosis, there are rare cases of patients remaining in therapy for longer periods of time. Early estimations of survival prognosis would allow rational decisions on complex therapy interventions, including radical surgery and robust systemic therapy regimens. Understandably, there is great interest in finding prognostic markers that can be used for patient stratification. We determined the role of various KRAS mutations in the prognosis of PDAC patients using biopsy samples and circulating tumor DNA. Methods: A total of 118 patients with PDAC, clinically confirmed by endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNB), were included in the study. DNA was extracted from cytological slides following a standard cytology evaluation to ensure adequacy (viability and quantity) and to mark the tumor cell fraction. Circulating tumor DNA (ctDNA) was extracted from plasma samples of 45 patients in stage IV of the disease. KRAS mutations in exons 12 and 13 were detected by denaturing capillary electrophoresis (DCE), revealing a minute presence of mutation-specific heteroduplexes. Kaplan-Meier survival curves were calculated for individual KRAS mutation types. Results:KRAS mutations were detected in 90% of tissue (106/118) and 44% of plasma (20/45) samples. All mutations were localized at exon 2, codon 12, with G12D (GGT > GAT) being the most frequent at 44% (47/106) and 65% (13/20), followed by other types including G12V (GGT > GTT) at 31% (33/106) and 10% (2/20), G12R (GGT > CGT) at 17% (18/106) and 10% (2/20), G12C (GGT/TGT) at 5% (5/106) and 0% (0/20) and G12S (GGT/AGT) at 1% (1/106) and 5% (1/20) in tissue and plasma samples, respectively. Two patients had two mutations simultaneously (G12V + G12S and G12D + G12S) in both types of samples (2%, 2/106 and 10%, 2/20 in tissue and plasma samples, respectively). The median survival of patients with the G12D mutation in tissues was less than half that of other patients (median survival 101 days, 95% CI: 80-600 vs. 228 days, 95% CI: 184-602), with a statistically significant overall difference in survival (p = 0.0080, log-rank test), and furthermore it was less than that of all combined patients with other mutation types (101 days, 95% CI: 80-600 vs. 210 days, 95% CI: 161-602, p = 0.0166). For plasma samples, the survival of patients with this mutation was six times shorter than that of patients without the G12D mutation (27 days, 95% CI: 8-334 vs. 161 days, 95% CI: 107-536, p = 0.0200). In contrast, patients with detected KRAS G12R in the tissue survived nearly twice as long as other patients in the aggregate (286 days, 95% CI: 70-602 vs. 162 days, 95% CI: 122-600, p = 0.0374) or patients with other KRAS mutations (286 days, 95% CI: 70-602 vs. 137 days, 95% CI: 107-600, p = 0.0257). Conclusions: Differentiation of specific KRAS mutations in EUS-FNB and ctDNA (above all, the crucial G12D and G12R) is feasible in routine management of PDAC patients and imperative for assessment of prognosis.

• MeSH
• biopsie tenkou jehlou pod endosonografickou kontrolou * MeSH
• cirkulující nádorová DNA genetika   krev   MeSH
• dospělí MeSH
• duktální karcinom slinivky břišní * genetika   patologie   krev   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mutace * MeSH
• nádorové biomarkery genetika   MeSH
• nádory slinivky břišní * genetika   patologie   mortalita   MeSH
• prognóza MeSH
• protoonkogenní proteiny p21(ras) * genetika   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• tekutá biopsie metody   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Colorectal cancer (CRC) is a leading global cause of illness and death. There is a need for identification of better prognostic markers beyond traditional clinical variables like grade and stage. Previous research revealed that abnormal expression of cytokeratin 7 (CK7) and loss of the intestinal-specific Special AT-rich sequence-binding protein 2 (SATB2) are linked to poor CRC prognosis. This study aimed to explore these markers' prognostic significance alongside two extraintestinal mucins (MUC5AC, MUC6), claudin 18, and MUC4 in 285 CRC cases using immunohistochemistry on tissue microarrays (TMAs). CK7 expression and SATB2-loss were associated with MUC5AC, MUC6, and claudin 18 positivity. These findings suggest a distinct "non-intestinal" immunohistochemical profile in CRC, often right-sided, SATB2-low, with atypical expression of CK7 and non-colorectal mucins (MUC5AC, MUC6). Strong MUC4 expression negatively impacted cancer-specific survival (hazard ratio = 2.7, p = 0.044). Genetic analysis via next-generation sequencing (NGS) in CK7 + CRCs and those with high MUC4 expression revealed prevalent mutations in TP53, APC, BRAF, KRAS, PIK3CA, FBXW7, and SMAD4, consistent with known CRC mutation patterns. NGS also identified druggable variants in BRAF, PIK3CA, and KRAS. CK7 + tumors showed intriguingly common (31.6%) BRAF V600E mutations corelating with poor prognosis, compared to the frequency described in the literature and databases. Further research on larger cohorts with a non-colorectal immunophenotype and high MUC4 expression is needed.

• MeSH
• dospělí MeSH
• fenotyp MeSH
• fosfatidylinositol-3-kinasy třídy I genetika   metabolismus   MeSH
• imunohistochemie * MeSH
• keratin-7 metabolismus   genetika   MeSH
• kolorektální nádory * genetika   patologie   metabolismus   mortalita   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mucin 4 genetika   metabolismus   MeSH
• mucin 5AC genetika   metabolismus   MeSH
• mucin 6 genetika   metabolismus   MeSH
• mutace MeSH
• nádorové biomarkery * genetika   metabolismus   MeSH
• prognóza MeSH
• protoonkogenní proteiny B-Raf genetika   MeSH
• protoonkogenní proteiny p21(ras) genetika   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• transkripční faktory MeSH
• vazebné proteiny DNA v oblastech připojení k matrix * genetika   metabolismus   MeSH
• vysoce účinné nukleotidové sekvenování MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Pancreatic ductal adenocarcinoma (PDAC) presents significant challenges for targeted clinical interventions due to prevalent KRAS mutations, rendering PDAC resistant to RAF and MEK inhibitors (RAFi and MEKi). In addition, responses to targeted therapies vary between patients. Here, we explored the differential sensitivities of PDAC cell lines to RAFi and MEKi and developed an isogenic pair comprising the most sensitive and resistant PDAC cells. To simulate patient- or tumor-specific variations, we constructed cell-line-specific mechanistic models based on protein expression profiling and differential properties of KRAS mutants. These models predicted synergy between two RAFi with different conformation specificity (type I1⁄2 and type II RAFi) in inhibiting phospho-ERK (ppERK) and reducing PDAC cell viability. This synergy was experimentally validated across all four studied PDAC cell lines. Our findings underscore the need for combination approaches to inhibit the ERK pathway in PDAC.

• MeSH
• duktální karcinom slinivky břišní * farmakoterapie   patologie   metabolismus   MeSH
• inhibitory proteinkinas * farmakologie   MeSH
• lidé MeSH
• MAP kinasový signální systém * účinky léků   MeSH
• nádorové buněčné linie MeSH
• nádory slinivky břišní * patologie   farmakoterapie   metabolismus   MeSH
• protoonkogenní proteiny p21(ras) metabolismus   genetika   MeSH
• raf kinasy metabolismus   antagonisté a inhibitory   MeSH
• synergismus léků MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH