Abstract 449: Discovery of novel MTA-cooperative PRMT5 inhibitors as targeted therapeutics for MTAP-deleted cancers

Homozygous deletions of p16/CDKN2a (cyclin dependent kinase inhibitor 2A) locus are prevalent in cancer and often involve co-deletion of adjacent genes. Metabolic gene MTAP (methylthioadenosine phosphorylase) is localized at the 9p21 chromosome in the close proximity to p16/CDKN2A tumor-suppressor locus. Co-deletion of MTAP may be observed in 80-90% of all tumors harboring homozygous deletion of CDKN2A, which represents 10 - 15% of all human tumors. Many of these tumor types, such as non-small cell lung cancer, pancreatic adenocarcinoma, glioblastoma or mesothelioma are associated with poor prognosis, representing a significant unmet medical need. MTAP deletion results in a massive accumulation of methylthioadenosine (MTA) in cells. MTA in high concentrations is a very selective inhibitor of PRMT5 methyltransferase, competitive for the substrate: S-adenosylmethionine (SAM). Accumulation of MTA in cells with MTAP deletion causes partial inhibition of the methylation activity of PRMT5, which in turn reduces the level of symmetric arginine dimethylation of the whole proteome, and thus an increased sensitivity of cells to modulation of methylosome activity. Therapeutic targeting of PRMT5 in homozygous MTAP-deleted cancers constitute a promising strategy of selective killing of genetically defined cancer cells. Ryvu has identified a series of MTA-cooperative PRMT5 inhibitors which have good drug-like physicochemical properties and block methyltransferase activity with nanomolar IC50 values. Structurally enabled hit generation and optimization allowed quick expansion and delivery of several generations of compounds with novel IP, high target engagement in cells and selective potency in MTAP-deleted cell lines. Ryvu compounds selectively inhibit growth of MTAP-deleted cancer cells in prolonged 3D culture, which strongly correlates with inhibition of PRMT5-dependent protein symmetric dimethylation (SDMA) in those cells. Selectivity between effects observed in MTAP-deleted and WT cells exceeds 100-fold both for SDMA and growth inhibition. The DMPK profile of these compounds allows for oral administration, which enables testing antitumor activity in MTAP null tumor xenograft-bearing mice. Efficacy studies with our lead compound resulted in demonstration of tumor growth inhibition in MTAP -/- model, accompanied by significant inhibition of target proximal PD biomarker.  Overall, these studies provide a rationale for further optimization of our chemical series of MTA-cooperative PRMT5 inhibitors towards a clinical candidate. 

Citation Format: Anna Bartosik, Adam Radzimierski, Aneta Bobowska, Oleksandr Levenets, Agata Stachowicz, Kamil Kuś, Kinga Michalik, Katarzyna Banaszak, Monika Madej, Marta Skoda, Kamila Kozłowska-Tomczyk, Igor Tomczyk, Karolina Pyziak, Dobrosława Krzemień, Mirosława Gładysz, Paulina Podkalicka, Aniela Gołas, Karolina Gluza, Grzegorz Satała, Andrzej Gondela, Marta Sowińska, Nicolas Boutard, Agata Chłopek, Aleksandra Więckowska, Daria Szukiel, Grzegorz Ćwiertnia, Iana Levenets, Karol Zuchowicz, Klara Korta-Piątek, Marcin Nowogródzki, Marek Wronowski, Marianna Girardi, Mateusz Świrski, Oleksandr Popika, Paulina Niedziejko-Ćwiertnia, Pierpaolo Cordone, Przemysław Wyrębek, Quỳnh Vũ, Sujit Sasmal, Svitlana Sukhomlinova, Magdalena Miodek, Jacek Faber, Anna Kowal-Chwast, Róża Starczak, Sanja Novak Ratajczak, Agnieszka Świrska, Dawid Gogola, Paweł Guzik, Martin Swarbrick, Mateusz Nowak. Discovery of novel MTA-cooperative PRMT5 inhibitors as targeted therapeutics for MTAP-deleted cancers  [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 449.

Abstract 1806: Discovery of novel MTA-cooperative PRMT5 inhibitors as a targeted therapeutics for MTAP deleted cancers

Targeting PRMT5 in MTAP-deleted tumors in a synthetic lethal approach represents a promising antitumor strategy across many tumor types. Metabolic gene MTAP is localized at the 9p21 chromosome in the close proximity to CDKN2A tumor-suppressor locus. Co-deletion of MTAP may be observed in 80-90% of all tumors harboring homozygous deletion of CDKN2A, which represents 10-15% of all human tumors. MTAP deletion results in a massive accumulation of methylotioadenosine (MTA) in cells. MTA in high concentrations is a selective inhibitor of PRMT5 type II methyltransferase. PRMT5 conjugated with WD-repeat containing protein (WDR77) builds methylosome, which regulates essential cellular functions via symmetric demethylation (SDMA) of target proteins involved in regulation of gene expression, RNA splicing, signal transduction, metabolism and other functions. Accumulation of MTA in cells with MTAP deletion causes a partial inhibition of the methylation activity of PRMT5, which in turn reduces the level of symmetric arginine dimethylation of the whole proteome, and thus an increased sensitivity of cells to modulation of the methylosome activity. Therapeutic targeting of PRMT5 in homozygous MTAP-deleted cancers constitute a promising strategy of selective killing of genetically defined cancer cells. Currently available clinical stage PRMT5 small molecule inhibitors are not MTA-cooperative and therefore are not selective in tumors harboring MTAP deletion. Here we present MTA-cooperative PRMT5 inhibitors, which selectively inhibit the growth of MTAP deleted cancer cells. Ryvu has identified a series of MTA-cooperative PRMT5 inhibitors which have good drug-like physicochemical properties and block methyltransferase activity with nanomolar IC50 values. Ryvu compounds selectively inhibit growth of MTAP deleted cancer cells in prolonged 3D culture, which strongly correlates with inhibition of PRMT5-dependent protein symmetric demethylation (SDMA) in those cells. Selectivity between effects observed in MTAP deleted and WT cells exceeds 100-fold both for SDMA and growth inhibition. The DMPK profile of these compounds allows for oral administration, which enables testing dose-dependent antitumor activity in MTAP null tumor xenograft-bearing mice. Overall, these studies provide rationale for further optimization of chemical series towards clinical candidate. 

Citation Format: Oleksandr Levenets, Anna Bartosik, Marta Sowińska, Karol Zuchowicz, Sujit Sasmal, Klara Korta-Piątek, Adam Radzimierski, Paulina Niedziejko, Oleksandr Popika, Mateusz Świrski, Agata Stachowicz, Maciej Mikulski, Magdalena Sieprawska-Lupa, Katarzyna Banaszak, Kinga Michalik, Kamil Kuś, Monika Madej, Adrian Podkowa, Karolina Gluza, Grzegorz Satała, Ewelina Cieluch, Dobrosława Krzemień, Andrzej Gondela, Grzegorz Ćwiertnia, Marek Wronowski, Nicolas Boutard, Aleksandra Więckowska, Joanna Zezula, Justyna Jabłońska, Mirosława Gładysz, Igor Tomczyk, Jacek Faber, Marcin Serocki, Eliza Drwal, Kamila Kozłowska-Tomczyk, Marta Skoda, Martin Swarbrick, Krzysztof Brzózka, Mateusz Nowak. Discovery of novel MTA-cooperative PRMT5 inhibitors as a targeted therapeutics for MTAP deleted cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1806.

Bone Marrow-Derived VSELs Engraft as Lung Epithelial Progenitor Cells after Bleomycin-Induced Lung Injury

BACKGROUND

Alveolar type 2 (AT2) cells and bronchioalveolar stem cells (BASC) perform critical regenerative functions in response to lung damage. Published data show that nonhematopoietic, bone marrow-derived "very small embryonic-like stem cells" (VSELs) can differentiate in vivo into surfactant protein C (SPC)-producing AT2 cells in the lung. Here, we test directly whether VSEL-derived BASC and AT2 cells function to produce differentiated progeny.

METHODS

using a reporter mouse in which the H2B-GFP fusion protein is driven from the murine SPC promoter, we tested whether bone marrow-derived VSELs or non-VSEL/nonhematopoietic stem cells (non-VSEL/non-HSCs) can differentiate into AT2 and BASC cells that function as progenitor cells. Immediately following bleomycin administration, WT recipient mice underwent intravenous administration of VSELs or non-VSEL/non-HSCs from SPC H2B-GFP mice. GFP+ AT2 and BASC were isolated and tested for progenitor activity using in vitro organoid assays.

RESULTS

after 21 days in vivo, we observed differentiation of VSELs but not non-VSEL/non-HSCs into phenotypic AT2 and BASC consistent with previous data in irradiated recipients. Subsequent in vitro organoid assays revealed that VSEL-derived AT2 and BASC maintained physiological potential for differentiation and self-renewal.

CONCLUSION

these findings prove that VSELs produce functional BASC and AT2 cells, and this may open new avenues using VSELs to develop effective cell therapy approaches for patients with lung injury.

The potential association between a new angiogenic marker fractalkine and a placental vascularization in preeclampsia

Purpose

Impaired angiogenesis is one of the most common findings in preeclamptic placentas. A new angiogenetic role of fractalkine (CX3CL1) is recently recognized apart from inflammatory activity. In this study, a link between CX3CL1 and the development of placental vasculature in preeclampsia was examined.

Methods

The study comprised 52 women allocated to Group 1 (normotensive, n = 23) and Group 2 (preeclampsia, n = 29). In each group Doppler parameters, serum levels of CX3CL1, soluble fms-like tyrosine kinase-1 (sFlt-1), and placental growth factor (PlGF) were assessed between 30 and 32 week of pregnancy. After the delivery, placental samples were taken and the vascularization and expression of CX3CR1 receptor were assessed after immunostaining.

Results

CX3CL1 and sFlt-1 serum levels were significantly higher levels in Group 2 vs Group 1, while PlGF serum levels was significantly lower in Group 2. Lower cerebroplacental ratio (CPR) was observed in Group 2. The vascular/extravascular tissue index (V/EVTI) was significantly lower in Group 2, while compared to Group 1, with the lowest value in the fetus growth restriction (FGR) subgroup (0.18 ± 0.02; 0.24 ± 0.03; 0.16 ± 0.02, respectively). The expression of examined CX3CR1 was higher in Group 2, while compared to Group 1, reaching the highest values in FGR subgroup. There was a moderate negative correlation between birth weight, V/EVTI and CX3CL1 serum level and CX3CR1 placental expression in the group of pregnancies complicated with preeclampsia.

Conclusion

The significant underdevelopment of placental vascular network in preeclampsia is associated with the change in the CX3CL1/CX3CR1 system, especially in FGR complicated pregnancies.

Can adipokine visfatin be a novel marker of pregnancy-related disorders in women with obesity?

Overweight and obesity have become a dangerous disease requiring multiple interventions, treatment and preventions. In women of reproductive age, obesity is one of the most common medical conditions. Among others, obese state is characterized by low-grade systemic inflammation and enhanced oxidative stress. Increased maternal body mass index might amplify inflammation and reactive oxygen species production, which is associated with unfavourable clinical outcomes that affect both mother and child. Intrauterine growth retardation, preeclampsia, or gestational diabetes mellitus are examples of the hampered maternal and foetoplacental unit interactions. Visfatin is the obesity-related adipokine produced mainly by the visceral adipose tissue. Visfatin affects glucose homeostasis, as well as the regulation of genes related to oxidative stress and inflammatory response. Here, we review visfatin interactions in pregnancy-related disorders linked to obesity. We highlight the possible predictive and prognostic value of visfatin in diagnostic strategies on gravidas with obesity.

Mild anemia during pregnancy upregulates placental vascularity development

The connection between maternal hematological status and pregnancy outcome has been shown by many independent researchers. Attention was initially focused on the adverse effects of moderate and severe anemia. Interestingly, some studies revealed that mild anemia was associated with optimal fetal development and was not affecting pregnancy outcome. The explanation for this phenomenon became a target for scientists. Hemodilution, physiologic anemia and relative decrease in hemoglobin concentration are the changes observed during pregnancy but they do not explain the reasons for the positive influence of mild anemia on a fetomaternal unit. It is hypothesized that hemodilution facilitates placental perfusion because blood viscosity is reduced. Subsequently, it may lead to a decline in hemoglobin concentration. Anemia from its definition implies decreased oxygen carrying capacity of the blood and can result in hypoxemia and even hypoxia, which is a common factor inducing new blood vessels formation. Therefore, we raised the hypothesis that the lowered hemoglobin concentration during pregnancy may upregulate vascular growth factor receptors expression such as VEGFR-1 (Flt-1) and VEGFR-2 (FLK-1/KDR). Consecutively, increased fetoplacental vasculogenesis and angiogenesis provide further expansion of vascular network development, better placental perfusion and hence neither fetus nor the mother are affected.

The Molecular Influence of Graphene and Graphene Oxide on the Immune System Under In Vitro and In Vivo Conditions

Graphene and graphene oxide (GO), due to their physicochemical properties and biocompatibility, can be used as an innovative biomedical material in biodetection, drug distribution in the body, treating neoplasms, regenerative medicine, and in implant surgery. Research on the biomedical use of graphene and GO that has been carried out until now is very promising and shows that carbon nanomaterials present high biocompatibility. However, the intolerance of the immune system to graphene nanomaterials, however low, may in consequence make it impossible to use them in medicine. This paper shows the specific mechanism of the molecular influence of graphene and GO on macrophages and lymphocytes under in vitro and in vivo conditions and their practical application in medicine. Under in vitro conditions graphene and GO cause an increased production of pro-inflammatory cytokines, mainly IL-1, IL-6, IL-10 and TNF-α, as a result of the activation of Toll-like receptors in macrophages. Graphene activates apoptosis in macrophages through the TGFbr/Smad/Bcl-2 pathway and also through JNK kinases that are stimulated by an increase of ROS in the cell or through a signal received by Smad proteins. Under in vivo conditions, graphene nanomaterials induce the development of the local inflammatory reaction and the development of granulomas in parenchymal organs. However, there is a huge discrepancy between the results obtained by different research groups, which requires a detailed analysis. In this work we decided to collect and analyze existing research and tried to explain the discrepancies. Understanding the precise mechanism of how this nanomaterial influences immune system cells allows estimating the potential influence of grapheme and GO on the human body.

Apigenin inhibits TGF-β1 induced fibroblast-to-myofibroblast transition in human lung fibroblast populations

BACKGROUND

Flavonoids are dietary plant compounds suspected to reduce the incidence of chronic diseases in several regions of the world. Due to anti-allergic and anti-inflammatory activities, apigenin (4',5,7,-trihydroxyflavone) is thought to interfere with crucial events in the pathomechanism of asthma. However, the effect of apigenin on TGF-β-induced fibroblast-to-myofibroblast transition (FMT) in human lung fibroblast populations, a key event in asthma progression, has not yet been addressed.

METHODS

Primary human bronchial fibroblasts (HBFs) propagated from ex vivo bronchial biopsies derived from patients with diagnosed asthma and human embryonic lung IMR-90 fibroblasts were cultured in vitro and treated with TGF-β1 and apigenin. The myofibroblast fraction in fibroblast populations was evaluated by immunocytochemistry. Expression of α-smooth muscle actin (α-SMA) and tenascin C were assessed at the mRNA and protein level by real-time RT-PCR and immunoblotting, respectively. Additionally, proliferation and viability tests and time lapse-monitoring of movement of individual HBFs and IMR-90 cells were evaluated.

RESULTS

We show that apigenin attenuates TGF-β1-induced FMT in cultures of HBFs, and the magnitude of this attenuation was found to be similar to that observed in the established cell line of lung IMR-90 fibroblasts. Notably, FMT inhibition was observed at low (≈10 μM), non-cytotoxic and non-cytostatic apigenin concentrations and could be correlated with the inhibition of α-SMA and tenascin C expression in HBFs at the mRNA level.

CONCLUSIONS

Our data are the first to demonstrate that apigenin inhibits the TGF-β1-induced expansion of hyper-contractile, α-smooth muscle actin - positive myofibroblasts within populations of HBFs derived from asthmatic patients. They also indicate the possible interference of apigenin with bronchial wall remodeling during the asthmatic process in vivo.

Sn/Pt(110) bimetallic surfaces: formation and oxygen adsorption

Submonolayer coverage of Sn on a Pt(110) surface was studied by photoemission and low-energy electron diffraction. Deposition of less than 0.6 ML at 300 K gives rise to a c(2 × 2) surface reconstruction with weak diffraction spots at the very beginning of growth, and no other LEED patterns were found at this temperature. A new (4 × 1) Sn/Pt(110) surface structure was observed after flashing to 570 K a coverage of 0.64 ML. The total Sn coverage decreased to 0.58 ML after flashing as some of the atoms diffused into deeper layers. Different Sn phases were identified on the (4 × 1) Sn/Pt(110) surface: two types of surface Sn atoms in different adsorption sites, a subsurface Sn-Pt intermetallic layer and Sn-Pt surface islands. To investigate chemical reactivity, 0.25 ML Sn/Pt(110) and 0.58 ML (4 × 1) Sn/Pt(110) surfaces were exposed to 1000 L of O(2) at 300 K. Analyses of the photoemission data provide evidence for the formation of tin oxide. The interaction with oxygen of the two surfaces is similar, independent of surface structure and the composition of the subsurface layers. The Sn concentration in the interface intermetallic layer is the main factor which influences the oxygen adsorption.

Palladium interaction with CeO(2), Sn-Ce-O and Ga-Ce-O layers

Using photoemission, we have studied the interaction of palladium with thin layers of stoichiometric ceria (Ce(4+) character) and two mixed oxides, Ga-Ce-O and Sn-Ce-O, where cerium in the Ce(3+) oxidation state is present. Palladium was found to partially reduce the CeO(2) layer by introducing oxygen vacancies most probably in the vicinity of the growing Pd particles. In mixed oxide systems palladium very strongly interacts with both added metals-gallium and tin-leading to a breaking of metal-ceria bonds and the establishment of Pd-Ga(Sn) intermetallic compounds. As a consequence the ceria reoxidizes back to a Ce(4+) oxidation state.