Activation of the ERK pathway is a hallmark of cancer, and targeting of upstream signaling partners led to the development of approved drugs. Recently, SCH772984 has been shown to be a selective and ...potent ERK1/2 inhibitor. Here we report the structural mechanism for its remarkable selectivity. In ERK1/2, SCH772984 induces a so-far-unknown binding pocket that accommodates the piperazine-phenyl-pyrimidine decoration. This new binding pocket was created by an inactive conformation of the phosphate-binding loop and an outward tilt of helix αC. In contrast, structure determination of SCH772984 with the off-target haspin and JNK1 revealed two canonical but distinct type I binding modes. Notably, the new binding mode with ERK1/2 was associated with slow binding kinetics in vitro as well as in cell-based assay systems. The described binding mode of SCH772984 with ERK1/2 enables the design of a new type of specific kinase inhibitors with prolonged on-target activity.
Local interstellar spectra (LIS) for protons, helium, and antiprotons are built using the most recent experimental results combined with state-of-the-art models for propagation in the Galaxy and ...heliosphere. Two propagation packages, GALPROP and HelMod, are combined to provide a single framework that is run to reproduce direct measurements of cosmic-ray (CR) species at different modulation levels and at both polarities of the solar magnetic field. To do so in a self-consistent way, an iterative procedure was developed, where the GALPROP LIS output is fed into HelMod, providing modulated spectra for specific time periods of selected experiments to compare with the data; the HelMod parameter optimization is performed at this stage and looped back to adjust the LIS using the new GALPROP run. The parameters were tuned with the maximum likelihood procedure using an extensive data set of proton spectra from 1997 to 2015. The proposed LIS accommodate both the low-energy interstellar CR spectra measured by Voyager 1 and the high-energy observations by BESS, Pamela, AMS-01, and AMS-02 made from the balloons and near-Earth payloads; it also accounts for Ulysses counting rate features measured out of the ecliptic plane. The found solution is in a good agreement with proton, helium, and antiproton data by AMS-02, BESS, and PAMELA in the whole energy range.
The local interstellar spectrum (LIS) of cosmic-ray (CR) electrons for the energy range 1 MeV to 1 TeV is derived using the most recent experimental results combined with the state-of-the-art models ...for CR propagation in the Galaxy and in the heliosphere. Two propagation packages, GALPROP and HelMod, are combined to provide a single framework that is run to reproduce direct measurements of CR species at different modulation levels, and at both polarities of the solar magnetic field. An iterative maximum-likelihood method is developed that uses GALPROP-predicted LIS as input to HelMod, which provides the modulated spectra for specific time periods of the selected experiments for model-data comparison. The optimized HelMod parameters are then used to adjust GALPROP parameters to predict a refined LIS with the procedure repeated subject to a convergence criterion. The parameter optimization uses an extensive data set of proton spectra from 1997 to 2015. The proposed CR electron LIS accommodates both the low-energy interstellar spectra measured by Voyager 1 as well as the high-energy observations by PAMELA and AMS-02 that are made deep in the heliosphere; it also accounts for Ulysses counting rate features measured out of the ecliptic plane. The interstellar and heliospheric propagation parameters derived in this study agree well with our earlier results for CR protons, helium nuclei, and anti-protons propagation and LIS obtained in the same framework.
Local interstellar spectra (LIS) of secondary cosmic-ray (CR) nuclei, lithium, beryllium, boron, and partially secondary nitrogen, are derived in the rigidity range from 10 MV to ∼200 TV using the ...most recent experimental results combined with state-of-the-art models for CR propagation in the Galaxy and in the heliosphere. The lithium spectrum appears somewhat flatter at high energies compared to other secondary species, which may imply a primary lithium component. Two propagation packages, GALPROP and HelMod, are combined to provide a single framework that is run to reproduce direct measurements of CR species at different modulation levels, and at both polarities of the solar magnetic field. An iterative maximum-likelihood method is developed that uses GALPROP-predicted LIS as input to HelMod, which provides the modulated spectra for specific time periods of the selected experiments for the model-data comparison. The proposed LIS accommodates the low-energy interstellar spectra measured by Voyager 1, the High Energy Astrophysics Observatory-3 (HEAO-3), and the Cosmic Ray Isotope Spectrometer on board of the Advanced Composition Explorer (ACE/CRIS), as well as the high-energy observations by the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA), Alpha Magnetic Spectrometer-02 (AMS-02), and earlier experiments that are made deep in the heliosphere. The interstellar and heliospheric propagation parameters derived in this study are consistent with our earlier results for propagation of CR protons, helium, carbon, oxygen, antiprotons, and electrons.
Abstract
BRCA1
or
BRCA2
germline mutations predispose to breast, ovarian and other cancers. High-throughput sequencing of tumour genomes revealed that oncogene amplification and
BRCA1/2
mutations are ...mutually exclusive in cancer, however the molecular mechanism underlying this incompatibility remains unknown. Here, we report that activation of β-catenin, an oncogene of the WNT signalling pathway, inhibits proliferation of BRCA1/2-deficient cells. RNA-seq analyses revealed β-catenin-induced discrete transcriptome alterations in BRCA2-deficient cells, including suppression of
CDKN1A
gene encoding the CDK inhibitor p21. This accelerates G1/S transition, triggering illegitimate origin firing and DNA damage. In addition, β-catenin activation accelerates replication fork progression in BRCA2-deficient cells, which is critically dependent on p21 downregulation. Importantly, we find that upregulated p21 expression is essential for the survival of BRCA2-deficient cells and tumours. Thus, our work demonstrates that β-catenin toxicity in cancer cells with compromised BRCA1/2 function is driven by transcriptional alterations that cause aberrant replication and inflict DNA damage.
Abstract
Composition and spectra of Galactic cosmic rays (CRs) are vital for studies of high-energy processes in a variety of environments and on different scales, for interpretation of
γ
-ray and ...microwave observations, for disentangling possible signatures of new phenomena, and for understanding of our local Galactic neighborhood. Since its launch, AMS-02 has delivered outstanding-quality measurements of the spectra of
,
, and nuclei:
1
H–
8
O,
10
Ne,
12
Mg,
14
Si. These measurements resulted in a number of breakthroughs; however, spectra of heavier nuclei and especially low-abundance nuclei are not expected until later in the mission. Meanwhile, a comparison of published AMS-02 results with earlier data from HEAO-3-C2 indicates that HEAO-3-C2 data may be affected by undocumented systematic errors. Utilizing such data to compensate for the lack of AMS-02 measurements could result in significant errors. In this paper we show that
a fraction
of HEAO-3-C2 data
match
available AMS-02 measurements quite well and can be used together with Voyager 1 and ACE-CRIS data to make
predictions
for the local interstellar spectra (LIS) of nuclei that are not yet released by AMS-02. We are also updating our already-published LIS to provide a complete set from
1
H–
28
Ni in the energy range from 1 MeV nucleon
−1
to ∼100–500 TeV nucleon
−1
, thus covering 8–9 orders of magnitude in energy. Our calculations employ the G
al
P
rop
–H
el
M
od
framework, which has proved to be a reliable tool in deriving the LIS of CR
,
e
−
, and nuclei
1
H–
8
O.
Local interstellar spectra (LIS) of primary cosmic ray (CR) nuclei, such as helium, oxygen, and mostly primary carbon are derived for the rigidity range from 10 MV to ∼200 TV using the most recent ...experimental results combined with the state-of-the-art models for CR propagation in the Galaxy and in the heliosphere. Two propagation packages, GALPROP and HelMod, are combined into a single framework that is used to reproduce direct measurements of CR species at different modulation levels, and at both polarities of the solar magnetic field. The developed iterative maximum-likelihood method uses GALPROP-predicted LIS as input to HelMod, which provides the modulated spectra for specific time periods of the selected experiments for model-data comparison. The interstellar and heliospheric propagation parameters derived in this study are consistent with our prior analyses using the same methodology for propagation of CR protons, helium, antiprotons, and electrons. The resulting LIS accommodate a variety of measurements made in the local interstellar space (Voyager 1) and deep inside the heliosphere at low (ACE/CRIS, HEAO-3) and high energies (PAMELA, AMS-02).
In 2018, there were 400,000 new cases of renal cell carcinoma (RCC) globally, with 175,000 deaths attributable to the disease. Three quarters of patients have potentially curable localised disease at ...diagnosis; however, recurrence rates are as high as 40% following surgery. There are currently no adjuvant therapies in routine clinical use which reliably improve outcomes. Effective adjuvant therapy is an urgent unmet need to reduce recurrence risk and improve outcomes. Early efforts explored chemotherapy, radiotherapy, cytokine therapy, hormonal treatments and tumour cell vaccines as adjuvant therapies, however, have yielded disappointing results. More recently, interest shifted to evaluating tyrosine kinase inhibitors (TKIs) in the adjuvant setting, as they improve outcomes in metastatic disease. Five phase III clinical trials testing adjuvant use of a range of TKIs have been performed, with the results of a sixth trial awaited. Unfortunately, these studies have thus far yielded conflicting and disappointing results, and there is currently no strong evidence for routine adjuvant TKI therapy. In parallel, novel immunotherapy treatment approaches have recently been developed, transforming the management of a range of malignancies, particularly through immune checkpoint inhibitors (ICIs). These approaches are well established in the metastatic context in RCC, as well as in the adjuvant treatment of melanoma. On this basis, five phase III trials are currently ongoing to test the efficacy of a range of ICIs in adjuvant RCC patients, with initial results expected over the next few years. In this article, we review the current evidence for adjuvant therapies in RCC, discuss ongoing clinical trials and suggest directions for future work to address this unmet need.
Since its launch, the Alpha Magnetic Spectrometer-02 (AMS-02) has delivered outstanding quality measurements of the spectra of cosmic-ray (CR) species (
,
, and nuclei,
H-
O,
Ne,
Mg,
Si) which ...resulted in a number of breakthroughs. One of the latest long-awaited surprises is the spectrum of
Fe just published by AMS-02. Because of the large fragmentation cross section and large ionization energy losses, most of CR iron at low energies is local and may harbor some features associated with relatively recent supernova (SN) activity in the solar neighborhood. Our analysis of the new AMS-02 results, together with Voyager 1 and ACE-CRIS data, reveals an unexpected bump in the iron spectrum and in the Fe/He, Fe/O, and Fe/Si ratios at 1-2 GV, while a similar feature in the spectra of He, O, and Si and in their ratios is absent, hinting at a local source of low-energy CRs. The found excess extends the recent discoveries of radioactive
Fe deposits in terrestrial and lunar samples and in CRs. We provide an updated local interstellar spectrum (LIS) of iron in the energy range from 1 MeV nucleon
to ~10 TeV nucleon
. Our calculations employ the GALPROP-HELMOD framework, which has proved to be a reliable tool in deriving the LIS of CR
,
, and nuclei
⩽ 28.
Pre-clinically, phosphoinositide 3-kinase (PI3K) inhibition radiosensitises tumours by increasing intrinsic radiosensitivity and by reducing tumour hypoxia. We assessed whether buparlisib, a class 1 ...PI3K inhibitor, can be safely combined with radiotherapy in patients with non-small cell lung carcinoma (NSCLC) and investigated its effect on tumour hypoxia.
This was a 3 + 3 dose escalation and dose expansion phase I trial in patients with advanced NSCLC. Buparlisib dose levels were 50 mg, 80 mg and 100 mg once daily orally for 2 weeks, with palliative thoracic radiotherapy (20 Gy in 5 fractions) delivered during week 2. Tumour hypoxic volume (HV) was measured using 18F-fluoromisonidazole positron-emission tomography–computed tomography at baseline and following 1 week of buparlisib.
Twenty-one patients were recruited with 9 patients evaluable for maximum tolerated dose (MTD) analysis. No dose-limiting toxicity was reported; therefore, 100 mg was declared the MTD, and 10 patients received this dose in the expansion phase. Ninety-four percent of treatment-related adverse events were ≤grade 2 with fatigue (67%), nausea (24%) and decreased appetite (19%) most common per patient. One serious adverse event (grade 3 hypoalbuminaemia) was possibly related to buparlisib. No unexpected radiotherapy toxicity was reported. Ten (67%) of 15 patients evaluable for imaging analysis were responders with 20% median reduction in HV at the MTD.
This is the first clinical trial to combine a PI3K inhibitor with radiotherapy in NSCLC and investigate the effects of PI3K inhibition on tumour hypoxia. This combination was well tolerated and PI3K inhibition reduced hypoxia, warranting investigation into whether this novel class of radiosensitisers can improve radiotherapy outcomes.
•Buparlisib, a phosphoinositide 3-kinase (PI3K) inhibitor, is safe when combined with thoracic radiotherapy.•PI3K inhibition resulted in a rapid reduction in tumour hypoxia in non–small cell lung carcinoma.•This study supports the development of PI3K inhibitors as novel radiosensitisers.
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