The phosphatidylinositol 3‐kinase/protein kinase B (PI3K/AKT) signaling pathway is critically active in many cell types, both normal and neoplastic. Many small-molecule inhibitors targeting different levels of the PI3K/AKT pathway have been developed for cancer therapy, but their efficacy is reduced by compensatory pathway re-activation mechanisms, and their tolerability by toxic side effects. We studied this problem using cell lines representing diffuse large B-cell lymphoma (SUDHL-4 and OCI-Ly7), a genetically-encoded live-cell reporter of AKT activity, and 3 small-molecule inhibitors targeting different levels of the pathway: idelalisib (PI3Kδ), GSK2334470 (PDPK1), and ipatasertib (AKT). Half-maximal (IC50) concentrations of these inhibitors for AKT activity inhibition at 1 h, when used individually, were much lower than their IC50 values for reduction of viable cell number after 4 days. Time-course studies explained this discrepancy: AKT activity in the continuous presence of the inhibitors returned to normal after 24 h, and was supranormal after inhibitor removal. Combining all 3 inhibitors produced sustained inhibition of AKT activity, was broadly synergistic at reducing viable cell number, enabled substantially lower doses of each inhibitor to be used, and was enhanced further by the mTOR inhibitor rapamycin. Moreover, combined PDPK1 and AKT inhibition showed synergy with multiple different PI3K inhibitors. In a syngeneic mouse cell line model of lymphoma (A20), the triple combination showed antitumor activity and no evidence of toxicity. Our findings provide proof of concept suggesting further study of the safety and efficacy of low-dose multilevel PI3K/AKT pathway inhibition, for lymphoma and perhaps other cancers.
Doporučené postupy klinické péče o nosiče patogenních variant v klinicky relevantních genech predisponujících ke vzniku Lynchova syndromu a karcinomu kolorekta definují kroky primární a sekundární prevence, která by měla být osobám ve vysokém riziku vzniku dědičných nádorů v ČR poskytnuta. Tvorba doporučených postupů byla organizována pracovní skupinou onkogenetiky Společnosti lékařské genetiky a genomiky při České lékařské společnosti J. E. Purkyně ve spolupráci se zástupci onkologie, onkogynekologie a gastroenterologie. Doporučené postupy vycházejí z aktuálních doporučení National Comprehensive Cancer Network (NCCN), Evropské společnosti pro klinickou onkologii (ESMO) a zohledňují kapacitní možnosti našeho zdravotnictví.
The guidelines for clinical practice for carriers of pathogenic variants in clinically relevant genes predisposing to Lynch syndrome and colorectal cancer define the steps of primary and secondary prevention that should be provided to the individuals at high risk of developing hereditary cancer in the Czech Republic. The drafting of the guidelines was organized by the Oncogenetics Working Group of the Society for Medical Genetics and Genomics of J. E. Purkyně Czech Medical Society, in cooperation with representatives of oncology, oncogynecology, and gastroenterology. The guidelines are based on the current recommendations of the National Comprehensive Cancer Network (NCCN), European Society of Medical Oncology (ESMO) and take into account the capacity of the Czech healthcare system.
- MeSH
- adhezní molekula epiteliálních buněk genetika MeSH
- dědičné nepolypózní kolorektální nádory genetika MeSH
- genetická predispozice k nemoci * genetika MeSH
- kolorektální nádory * genetika MeSH
- mismatch repair endonukleáza PMS2 genetika MeSH
- MutL homolog 1 genetika MeSH
- směrnice pro lékařskou praxi jako téma MeSH
- zárodečné mutace genetika MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
- Geografické názvy
- Česká republika MeSH
Besides many other mutations in known cancer driver genes, mantle cell lymphoma (MCL) is characterized by recurrent genetic alterations of important regulators of the phosphoinositol-3-kinase (PI3K) cascade including PIK3CA gains and PTEN losses. To evaluate the biological and functional consequences of these aberrations in MCL, we have introduced transgenic expression of PIK3CA (PIK3CA UP) and performed knockout/knockdown of PTEN gene (PTEN KO/KD) in 5 MCL cell lines. The modified cell lines were tested for associated phenotypes including dependence on upstream B-cell receptor (BCR) signaling (by an additional BCR knockout). PIK3CA overexpression decreased the dependence of the tested MCL on prosurvival signaling from BCR, decreased levels of oxidative phosphorylation, and increased resistance to 2-deoxy-glucose, a glycolysis inhibitor. Unchanged protein kinase B (AKT) phosphorylation status and unchanged sensitivity to a battery of PI3K inhibitors suggested that PIK3CA gain might affect MCL cells in AKT-independent manner. PTEN KO was associated with a more distinct phenotype: AKT hyperphosphorylation and overactivation, increased resistance to multiple inhibitors (most of the tested PI3K inhibitors, Bruton tyrosine kinase inhibitor ibrutinib, and BCL2 inhibitor venetoclax), increased glycolytic rates with resistance to 2-deoxy-glucose, and significantly decreased dependence on prosurvival BCR signaling. Our results suggest that the frequent aberrations of the PI3K pathway may rewire associated signaling with lower dependence on BCR signaling, better metabolic and hypoxic adaptation, and targeted therapy resistance in MCL.
- MeSH
- chemorezistence genetika MeSH
- cílená molekulární terapie MeSH
- fosfatidylinositol-3-kinasy třídy I * genetika metabolismus MeSH
- fosfatidylinositol-3-kinasy metabolismus MeSH
- fosfohydroláza PTEN * metabolismus genetika MeSH
- lidé MeSH
- lymfom z plášťových buněk * farmakoterapie genetika metabolismus MeSH
- nádorové buněčné linie MeSH
- protoonkogenní proteiny c-akt metabolismus MeSH
- receptory antigenů B-buněk metabolismus MeSH
- signální transdukce MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: Monoallelic germline pathogenic variants (GPVs) in five Fanconi anemia (FA) genes (BRCA1/FANCS, BRCA2/FANCD1, PALB2/FANCN, BRIP1/FANCJ, and RAD51C/FANCO) confer an increased risk of breast (BC) and/or ovarian (OC) cancer, but the role of GPVs in 17 other FA genes remains unclear. METHODS: Here, we investigated the association of germline variants in FANCG/XRCC9 with BC and OC risk. RESULTS: The frequency of truncating GPVs in FANCG did not differ between BC (20/10,204; 0.20%) and OC (8/2966; 0.27%) patients compared to controls (6/3250; 0.18%). In addition, only one out of five tumor samples showed loss-of-heterozygosity of the wild-type FANCG allele. Finally, none of the nine functionally tested rare recurrent missense FANCG variants impaired DNA repair activities (FANCD2 monoubiquitination and FANCD2 foci formation) upon DNA damage, in contrast to all tested FANCG truncations. CONCLUSION: Our study suggests that heterozygous germline FANCG variants are unlikely to contribute to the development of BC or OC.
- MeSH
- dospělí MeSH
- genetická predispozice k nemoci * MeSH
- lidé středního věku MeSH
- lidé MeSH
- nádory prsu * genetika MeSH
- nádory vaječníků * genetika MeSH
- oprava DNA genetika MeSH
- protein FANCG * genetika MeSH
- senioři MeSH
- studie případů a kontrol MeSH
- zárodečné mutace * MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Doporučené postupy klinické péče o nosiče patogenních variant v klinicky relevantních nádorových predispozičních genech definují kroky primární a sekundární prevence, která by měla být těmto osobám ve vysokém riziku vzniku dědičných nádorů v ČR poskytnuta. Tvorba doporučení byla organizována pracovní skupinou onkogenetiky Společnosti lékařské genetiky a genomiky (SLG ČLS JEP) ve spolupráci se zástupci onkologie a onkogynekologie. Doporučené postupy vycházejí z aktuálních doporučení National Comprehensive Cancer Network (NCCN), European Society of Medical Oncology (ESMO) a zohledňují kapacitní možnosti našeho zdravotnictví.
The Guidelines for Clinical Practice for carriers of pathogenic variants in clinically relevant cancer predisposition genes define the steps of primary and secondary prevention that should be provided to these individuals at high risk of developing hereditary cancer in the Czech Republic. The drafting of the guidelines was organized by the Oncogenetics Working Group of the Society for Medical Genetics and Genomics of J. E. Purkyně Czech Medical Society (SLG ČLS JEP) in cooperation with the representatives of oncology and oncogynecology. The guidelines are based on the current recommendations of the National Comprehensive Cancer Network (NCCN), European Society of Medical Oncology (ESMO) and take into account the capacity of the Czech healthcare system.
- MeSH
- ATM protein genetika MeSH
- checkpoint kinasa 2 genetika MeSH
- genetická predispozice k nemoci * MeSH
- geny BRCA1 MeSH
- geny BRCA2 MeSH
- nádory prostaty diagnóza genetika prevence a kontrola MeSH
- nádory prsu diagnóza genetika prevence a kontrola MeSH
- nádory slinivky břišní diagnóza genetika prevence a kontrola MeSH
- nádory vaječníků diagnóza genetika prevence a kontrola MeSH
- primární prevence metody MeSH
- protein FANCN genetika MeSH
- sekundární prevence metody MeSH
- směrnice pro lékařskou praxi jako téma MeSH
- zárodečné mutace MeSH
BACKGROUND: Mantle cell lymphoma (MCL) is a chronically relapsing malignancy with deregulated cell cycle progression. We analyzed efficacy, mode of action, and predictive markers of susceptibility to palbociclib, an approved CDK 4/6 inhibitor, and its combination with venetoclax, a BCL2 inhibitor. METHODS: A panel of nine MCL cell lines were used for in vitro experiments. Four patient derived xenografts (PDX) obtained from patients with chemotherapy and ibrutinib-refractory MCL were used for in vivo proof-of-concept studies. Changes of the mitochondrial membrane potential, energy-metabolic pathways, AKT activity, and pro-apoptotic priming of MCL cells were evaluated by JC-1 staining, Seahorse XF analyser, genetically encoded fluorescent AKT reporter, and BH3 profiling, respectively. MCL clones with gene knockout or transgenic (over)expression of CDKN2A, MYC, CDK4, and RB1 were used to estimate impact of these aberrations on sensitivity to palbociclib, and venetoclax. RESULTS: Co-targeting MCL cells with palbociclib and venetoclax induced cytotoxic synergy in vitro and in vivo. Molecular mechanisms responsible for the observed synthetic lethality comprised palbociclib-mediated downregulation of anti-apoptotic MCL1, increased levels of proapoptotic BIM bound on both BCL2, and BCL-XL and increased pro-apoptotic priming of MCL cells mediated by BCL2-independent mechanisms, predominantly palbociclib-triggered metabolic and mitochondrial stress. Loss of RB1 resulted in palbociclib resistance, while deletion of CDKN2A or overexpression of CDK4, and MYC genes did not change sensitivity to palbociclib. CONCLUSIONS: Our data strongly support investigation of the chemotherapy-free palbociclib and venetoclax combination as an innovative treatment strategy for post-ibrutinib MCL patients without RB1 deletion.
Germline CHEK2 pathogenic variants confer an increased risk of female breast cancer (FBC). Here we describe a recurrent germline intronic variant c.1009-118_1009-87delinsC, which showed a splice acceptor shift in RNA analysis, introducing a premature stop codon (p.Tyr337PhefsTer37). The variant was found in 21/10,204 (0.21%) Czech FBC patients compared to 1/3250 (0.03%) controls (p = 0.04) and in 4/3639 (0.11%) FBC patients from an independent German dataset. In addition, we found this variant in 5/2966 (0.17%) Czech (but none of the 443 German) ovarian cancer patients, three of whom developed early-onset tumors. Based on these observations, we classified this variant as likely pathogenic.
- MeSH
- checkpoint kinasa 2 * genetika MeSH
- dospělí MeSH
- genetická predispozice k nemoci * genetika MeSH
- introny * genetika MeSH
- lidé středního věku MeSH
- lidé MeSH
- nádory prsu * genetika MeSH
- nádory vaječníků genetika MeSH
- prekurzory RNA genetika MeSH
- sestřih RNA * genetika MeSH
- zárodečné mutace * MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
- Německo MeSH
Diffuse large B cell lymphoma of activated B cell type (ABC-DLBCL), a major cell-of-origin DLBCL subtype, is characterized by chronic active B cell receptor (BCR) signaling and NF-κB activation, which can be explained by activating mutations of the BCR signaling cascade in a minority of cases. We demonstrate that autonomous BCR signaling, akin to its essential pathogenetic role in chronic lymphocytic leukemia (CLL), can explain chronic active BCR signaling in ABC-DLBCL. 13 of 18 tested DLBCL-derived BCR, including 12 cases selected for expression of IgM, induced spontaneous calcium flux and increased phosphorylation of the BCR signaling cascade in murine triple knockout pre-B cells without antigenic stimulation or external BCR crosslinking. Autonomous BCR signaling was associated with IgM isotype, dependent on somatic BCR mutations and individual HCDR3 sequences, and largely restricted to non-GCB DLBCL. Autonomous BCR signaling represents a novel immunological oncogenic driver mechanism in DLBCL originating from individual BCR sequences and adds a new dimension to currently proposed genetics- and transcriptomics-based DLBCL classifications.
Necroptosis is considered a programmed necrosis that requires receptor-interacting protein kinase 1 (RIPK1), receptor-interacting protein kinase 3 (RIPK3), and pore-forming mixed lineage kinase domain-like protein (MLKL) to trigger a regulated cell membrane lysis. Membrane rupture in necroptosis has been shown to fuel innate immune response due to release of damage-associated molecular patterns (DAMPs). Recently published studies indicate that mature erythrocytes can undergo necroptosis as well. In this review, we provide an outline of multiple cell death modes occurring in erythrocytes, discuss possible immunological aspects of diverse erythrocyte cell deaths, summarize available evidence related to the ability of erythrocytes to undergo necroptosis, outline key involved molecular mechanisms, and discuss the potential implication of erythrocyte necroptosis in the physiology and pathophysiology. Furthermore, we aim to highlight the interplay between necroptosis and eryptosis signaling in erythrocytes, emphasizing specific characteristics of these pathways distinct from their counterparts in nucleated cells. Thus, our review provides a comprehensive summary of the current knowledge of necroptosis in erythrocytes. To reflect critical differences between necroptosis of nucleated cells and necroptosis of erythrocytes, we suggest a term erythronecroptosis for necroptosis of enucleated cells.
- MeSH
- eryptóza MeSH
- erytrocyty * metabolismus patologie MeSH
- lidé MeSH
- nekroptóza * MeSH
- nekróza MeSH
- protein-serin-threoninkinasy interagující s receptory metabolismus MeSH
- proteinkinasy metabolismus MeSH
- signální transdukce MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
T-cell lymphomas (TCLs) are a rare and heterogeneous subgroup of non-Hodgkin lymphomas (NHLs), forming only 10 % of all NHL cases in Western countries. Resulting from their low incidence and heterogeneity, the current treatment outcome is generally unfavorable, with limited availability of novel therapeutic approaches. Therefore, the recent success of immune checkpoint inhibitors (ICIs) in cancer treatment motivated their clinical investigation in TCLs as well. Multiple studies showed promising results; however, cases of TCL hyperprogression following ICI treatment and secondary T-cell-derived malignancies associated with ICI treatment of other cancer types were also reported. In our review, we first briefly summarize classification of T-cell-derived malignancies, general anti-tumor immune response, immune evasion, and immune checkpoint signaling. Next, we provide an overview of immune checkpoint molecule deregulation in TCLs, summarize available studies of ICIs in TCLs, and review the above-mentioned safety concerns associa-ted with ICI treatment and T-cell-derived malignancies. Despite initial promising results, further studies are necessary to define the most suitable clinical applications and ICI therapeutic combinations with other novel treatment approaches within TCL treatment. ICIs, and their combinations, might hopefully bring the long awaited improvement for the treatment of T-cell-derived malignancies.
