A noble nexus: a phosphino-phen ligand for tethering precious metals.

Controlled formation of mixed-metal bimetallics was achieved via two derivatised 1,10-phenanthroline ligands bearing an imino- or amino-phosphine appendage at the 5-position. Selective coordination of the phen group to the [Re(CO)3Cl] core was achieved enabling precise construction of bimetallic complexes with a second rhenium centre or with gold. The mixed Ru/Au complex was similarly obtained with the imino-phosphine but access to the heterobimetallic iridium systems required prior formation of the P-bound gold complexes subsequent to the introduction of the [Ir(Ppy)2]+ fragment. The Re/Pd, Re/Pt, Ir/Pd and Ir/Pt compounds were prepared from the combination of κ-N'',P-Pd(Pt)Cl2 and the appropriate rhenium or iridium precursors. Spectroscopic and theoretical analyses have been employed to investigate the structural and electronic impact of the second metal.

Macrocyclic Inhibitors Targeting the Prime Site of the Fibrinolytic Serine Protease Plasmin.

Two series of macrocyclic inhibitors addressing the S1 pocket and the prime site of the fibrinolytic serine protease plasmin have been developed. In the first series, a P1 tranexamoyl residue was coupled to 4-aminophenylalanine in P1' position, which provided moderately potent inhibitors with inhibition constants around 1 µM. In the second series, a substituted biphenylalanine was incorporated as P1' residue leading to approximately 1000-fold stronger plasmin inhibitors, the best compounds possess subnanomolar inhibition constants. The most effective compounds already exhibit a certain selectivity as plasmin inhibitors compared to other trypsin-like serine proteases such as trypsin, plasma kallikrein, thrombin, activated protein Ca, as well as factors XIa and Xa. For inhibitor 28 of the second series, the co-crystal structure in complex with a Ser195Ala microplasmin mutant revealed that the P2' residue adopts multiple conformations. Most polar contacts to plasmin and surrounding water molecules are mediated through the P1 tranexamoyl residue, whereas the bound conformation of the macrocycle is mainly stabilized by two intramolecular hydrogen bonds.

Do NPM1 and FLT3-ITD mutations modify prognosis in patients treated with non-intensive regimens?

FLT3-ITD and NPM1 mutations are key to defining the genetic risk profile of acute myeloid leukemia (AML). We aimed to assess the prognostic features of the FLT3-ITD and NPM1 mutations in old and/or unfit individuals with AML treated with non-intensive therapies in the era before azacitidine-venetoclax approbation. The results of various non-intensive regimens were also compared. We conducted a retrospective analysis that included patients treated with different non-intensive regimens, between 2007 and 2020 from PETHEMA AML registry. We compiled 707 patients with a median age of 74 years and median follow-up time of 37.7 months. FLT3-ITD patients (N = 98) showed a non-significant difference in overall survival (OS) compared to FLT3-ITD negative-patients (N = 608) (P = 0.17, median OS was 5 vs 7.3 months respectively). NPM1-mutated patients (N = 144) also showed a non-significant difference with NPM1 wild type (N = 519) patients (P = 0.25, median OS 7.2 vs 6.8 respectively). In the Cox regression analysis neither NPM1 nor FLT3-ITD nor age were significant prognostic variables for OS prediction. Abnormal karyotype and a high leukocyte count showed a statistically significant deleterious effect. Azacitidine also showed better survival compared to FLUGA (low dose cytarabine plus fludarabine). NPM1 and FLT3-ITD seem to lack prognostic value in older/unfit AML patients treated with non-intensive regimens other than azacitidine-venetoclax combination.

Myoferlin: A Potential Marker of Response to Radiation Therapy and Survival in Locally Advanced Rectal Cancer.

PURPOSE: Patients with locally advanced rectal cancer often require neoadjuvant chemoradiation therapy to downstage the disease, but the response is variable with no predictive biomarkers. We have previously revealed through proteomic profiling that myoferlin is associated with response to radiation therapy. The aims of this study were to further validate this finding and explore the potential for myoferlin to act as a prognostic and/or therapeutic target. METHODS AND MATERIALS: Immunohistochemical analysis of a tissue microarray (TMA) for 111 patients was used to validate the initial proteomic findings. Manipulation of myoferlin was achieved using small interfering RNA, a small molecular inhibitor (wj460), and a CRISPR-Cas9 knockout cell line. Radiosensitization after treatment was assessed using 2-dimensional clonogenic assays, 3-dimensional spheroid models, and patient-derived organoids. Underlying mechanisms were investigated using electrophoresis, immunofluorescence, and immunoblotting. RESULTS: Analysis of both the diagnostic biopsy and tumor resection samples confirmed that low myoferlin expression correlated with a good response to neoadjuvant long-course chemoradiation therapy. High myoferlin expression was associated with spread to local lymph nodes and worse 5-year survival (P = .01; hazard ratio, 3.5; 95% CI, 1.27-10.04). This was externally validated using the Stratification in Colorectal Cancer database. Quantification of myoferlin using immunoblotting in immortalized colorectal cancer cell lines and organoids demonstrated that high myoferlin expression was associated with increased radioresistance. Biological and pharmacologic manipulation of myoferlin resulted in significantly increased radiosensitivity across all cell lines in 2-dimensional and 3-dimensional models. After irradiation, myoferlin knockdown cells had a significantly impaired ability to repair DNA double-strand breaks. This appeared to be mediated via nonhomologous end-joining. CONCLUSIONS: We have confirmed that high expression of myoferlin in rectal cancer is associated with poor response to neoadjuvant therapy and worse long-term survival. Furthermore, the manipulation of myoferlin led to increased radiosensitivity in vitro. This suggests that myoferlin could be targeted to enhance the sensitivity of patients with rectal cancer to radiation therapy, and further work is required.

Tuning Excited State Character in Iridium(III) Photosensitizers and Its Influence on TTA-UC.

A series of mixed ligand, photoluminescent organometallic Ir(III) complexes have been synthesized to incorporate substituted 2-phenyl-1H-naphtho[2,3-d]imidazole cyclometalating ligands. The structures of three example complexes were categorically confirmed using X-ray crystallography each sharing very similar structural traits including evidence of interligand hydrogen bond contacts that account for the shielding effects observed in the 1H NMR spectra. The structural iterations of the cyclometalated ligand provide tuning of the principal electronic transitions that determine the visible absorption and emission properties of the complexes: emission can be tuned in the visible region between 550 and 610 nm and with triplet lifetimes up to 10 µs. The nature of the emitting state varies across the series of complexes, with different admixtures of ligand-centered and metal-to-ligand charge transfer triplet levels evident. Finally, the use of the complexes as photosensitizers in triplet-triplet annihilation energy upconversion (TTA-UC) was investigated in the solution state. The study showed that the complexes possessing the longest triplet lifetimes showed good viability as photosensitizers in TTA-UC. Therefore, the use of an electron-withdrawing group on the 2-phenyl-1H-naphtho[2,3-d]imidazole ligand framework can be used to rationally promote TTA-UC using this class of complex.

Luminescent Pt(II) Complexes Using Unsymmetrical Bis(2-pyridylimino)isoindolate Analogues.

A series of ligands based upon a 1,3-diimino-isoindoline framework have been synthesized and investigated as pincer-type (N∧N∧N) chelates for Pt(II). The synthetic route allows different combinations of heterocyclic moieties (including pyridyl, thiazole, and isoquinoline) to yield new unsymmetrical ligands. Pt(L1-6)Cl complexes were obtained and characterized using a range of spectroscopic and analytical techniques: 1H and 13C NMR, IR, UV-vis and luminescence spectroscopies, elemental analyses, high-resolution mass spectrometry, electrochemistry, and one example via X-ray crystallography which showed a distorted square planar environment at Pt(II). Cyclic voltammetry on the complexes showed one irreversible oxidation between +0.75 and +1 V (attributed to Pt2+/3+ couple) and a number of ligand-based reductions; in four complexes, two fully reversible reductions were noted between -1.4 and -1.9 V. Photophysical studies showed that Pt(L1-6)Cl absorbs efficiently in the visible region through a combination of ligand-based bands and metal-to-ligand charge-transfer features at 400-550 nm, with assignments supported by DFT calculations. Excitation at 500 nm led to luminescence (studied in both solutions and solid state) in all cases with different combinations of the heterocyclic donors providing tuning of the emission wavelength around 550-678 nm.

Cannabinoids induce cell death in leukaemic cells through Parthanatos and PARP-related metabolic disruptions.

BACKGROUND: Several studies have described a potential anti-tumour effect of cannabinoids (CNB). CNB receptor 2 (CB2) is mostly present in hematopoietic stem cells (HSC). The present study evaluates the anti-leukaemic effect of CNB. METHODS: Cell lines and primary cells from acute myeloid leukaemia (AML) patients were used and the effect of the CNB derivative WIN-55 was evaluated in vitro, ex vivo and in vivo. RESULTS: We demonstrate a potent antileukemic effect of WIN-55 which is abolished with CB antagonists. WIN-treated mice, xenografted with AML cells, had better survival as compared to vehicle or cytarabine. DNA damage-related genes were affected upon exposure to WIN. Co-incubation with the PARP inhibitor Olaparib prevented WIN-induced cell death, suggesting PARP-mediated apoptosis which was further confirmed with the translocation of AIF to the nucleus observed in WIN-treated cells. Nicotinamide prevented WIN-related apoptosis, indicating NAD+ depletion. Finally, WIN altered glycolytic enzymes levels as well as the activity of G6PDH. These effects are reversed through PARP1 inhibition. CONCLUSIONS: WIN-55 exerts an antileukemic effect through Parthanatos, leading to translocation of AIF to the nucleus and depletion of NAD+, which are reversed through PARP1 inhibition. It also induces metabolic disruptions. These effects are not observed in normal HSC.

Genital chronic graft-versus-host disease: an unmet need that requires trained gynecologists.

OBJECTIVE: Menopause and chronic graft-versus-host disease (cGvHD) are the leading causes of morbidity after allogeneic hematopoietic stem cell transplantation (alloHSCT). Genitalia are one of the target organs of cGvHD causing sexual dysfunction and local symptoms, which may impair women's quality of life. The aim of this study is to describe the prevalence and clinical characteristics of genital cGvHD. METHODS: A retrospective cross-sectional observational study was performed including 85 women with alloHSCT. All women were diagnosed and counseled by a trained gynecologist. Health-related quality of life was assessed by the Cervantes Short-Form Scale and sexual function was evaluated by the Female Sexual Function Index. RESULTS: Seventeen women (20%) included in the study were diagnosed with genital cGvHD. The main complaints were vulvovaginal dryness (42.2%) and dyspareunia (29.4%), the presence of erythema/erythematous plaques (52.9%) being the most frequent sign. Median time from transplant to diagnosis of genital cGvHD was 17 months among those with mild involvement, 25 months for moderate and 42 months for severe forms. Mortality was 29.4% in patients who developed cGvHD with genital involvement versus 8.8% among those without (p = 0.012). CONCLUSION: Early gynecological evaluation might allow to identify patients with mild forms of genital cGvHD, potentially enabling better management and improved outcomes.

Alkyl chain functionalised Ir(iii) complexes: synthesis, properties and behaviour as emissive dopants in microemulsions.

Six iridium(iii) complexes of the general form [Ir(C^N)2(N^N)]X (where C^N = cyclometalating ligand; N^N = disubstituted 2,2'-bipyridine), and incorporating alkyl chains of differing lengths (C8, C10, C12), have been synthesised and characterised. The complexes have been characterised using a variety of methods including spectroscopies (NMR, IR, UV-Vis, luminescence) and analytical techniques (high resolution mass spectrometry, cyclic voltammetry, X-ray diffraction). Two dodecyl-functionalised complexes were studied for their behaviour in aqueous solutions. Although the complexes did not possess sufficient solubility to determine their critical micelle concentrations (CMC) in water, they were amenable for use as emissive dopants in a N-methyl C12 substituted imidazolium salt microemulsion carrier system with a CMC = 36.5 mM. The investigation showed that the metal doped microemulsions had increased CMCs of 40.4 and 51.3 mM and luminescent properties characterised by the dopant.

Synthesis and luminescent properties of hetero-bimetallic and hetero-trimetallic Ru(II)/Au(I) or Ir(III)/Au(I) complexes.

A series of Ru(II) and Ir(III) based photoluminescent complexes were synthesised that incorporate an ancillary 2,2'-bipyridine ligand adorned with either one or two pendant N-methyl imidazolium groups. These complexes have been fully characterised by an array of spectroscopic and analytical techniques. One Ir(III) example was unequivocally structurally characterised in the solid state using single crystal X-ray diffraction confirming the proposed formulation and coordination sphere. These complexes were then transformed into their heterometallic, Au(I)-containing, analogues in two steps to yield either bi- or trimetallic complexes that integrate {Au(PPh3)}+ units. X-ray diffraction was used to corroborate the solid state structure of the hetero bimetallic complex, based upon a Ru(II)-Au(I) species. The heterometallic complexes all displayed red photoluminescent features (λem = 616-629 nm) that were consistent with the parent Ru(II) or Ir(III) lumophores in each case. The modulation of the emission from the Ru(II)-Au(I) complexes was much more strongly evident than for the Ir(III)-Au(I) analogues, which is ascribed to the inherent differences in the specific triplet excited state character of the emitting states within each heterometallic species.

Polycationic Ru(II) Luminophores: Syntheses, Photophysics, and Application in Electrostatically Driven Sensitization of Lanthanide Luminescence.

A series of photoluminescent Ru(II) polypyridine complexes have been synthesized in a manner that varies the extent of the cationic charge. Two ligand systems (L1 and L2), based upon 2,2'-bipyridine (bipy) mono- or difunctionalized at the 5- or 5,5'-positions using N-methylimidazolium groups, were utilized. The resulting Ru(II) species therefore carried +3, +4, +6, and +8 complex moieties based on a [Ru(bipy)3]2+ core. Tetra-cationic [Ru(bipy)2(L2)][PF6]4 was characterized using XRD, revealing H-bonding interactions between two of the counteranions and the cationic unit. The ground-state features of the complexes were found to closely resemble those of the parent unfunctionalized [Ru(bipy)3]2+ complex. In contrast, the excited state properties produce a variation in emission maxima, including a bathochromic 44 nm shift of the 3MLCT band for the tetra-cationic complex; interestingly, further increases in overall charge to +6 and +8 produced a hypsochromic shift in the 3MLCT band. Supporting DFT calculations suggest that the trend in emission behavior may, in part, be due to the precise nature of the LUMO and its localization. The utility of a photoactive polycationic Ru(II) complex was then demonstrated through the sensitization of a polyanionic Yb(III) complex in free solution. The study shows that electrostatically driven ion pairing is sufficient to facilitate energy transfer between the 3MLCT donor state of the Ru(II) complex and the accepting 2F5/2 excited state of Yb(III).

2-(Thienyl)quinoxaline derivatives and their application in Ir(III) complexes yielding tuneable deep red emitters.

The synthesis and characterisation of eleven different 2-(thienyl)quinoxaline species that incorporate different points of functionality, including at the thiophene or quinoxaline rings, are described. These species display variable fluorescence properties in the visible region (λem = 401-491 nm) depending upon the molecular structures and extent of conjugation. The series of 2-(thienyl)quinoxaline species were then investigated as cyclometalating agents for Ir(III) to yield [Ir(C^N)2(bipy)]PF6 (where C^N = the cyclometalated ligand; bipy = 2,2'-bipyridine). Eight complexes were successfully isolated and fully characterised by an array of spectroscopic and analytical techniques. Two Ir(III) examples were structurally characterised in the solid state using single crystal X-ray diffraction; both structures confirmed the proposed formulations and coordination spheres in each case showing that the thiophene coordinates via a Ir-C bond. The photophysical properties of the complexes revealed that each complex is luminescent under ambient conditions with a range of emission wavelengths observed (665-751 nm) indicating that electronic tuning can be achieved via both the thienyl and quinoxaline moieties.

Lack of evidence that progesterone in ovulatory cycles causes breast cancer.

A recent Perspective article asserted that progesterone secretion during ovulatory cycles is the cause of breast cancer. However, we challenge most of the evidence developed in this publication. First, there is a lack of evidence that progesterone is mutagenic for breast cells. Cause of a cancer should mean initiation by mutation, as opposed to promotion. Second, subclinical ovulatory disturbances occur rather frequently in normal-length menstrual cycles. Third, the authors attribute a potential carcinogenic effect to progesterone secreted during menstrual cycles but not to progesterone during pregnancy. They did not discuss breast cancer evidence from progesterone/progestin therapeutics. They argue that in genetic primary amenorrhea, a hypothetic lower risk of breast cancer could be due to the lack of progesterone, despite the progesterone/progestin in hormone replacements these women receive. Fourth, they advocate a regulatory effect of progesterone on several genes potentially involved in cancer genesis. In particular, they attribute a lower risk of breast cancer in women with Mayer-Rokitansky-Küster-Hauser syndrome to a defect in the progesterone-stimulated Wnt4 gene. However, this defect is only present in a small subset. Thus, the postulated progesterone breast cancer risk is unconvincing, which we discuss point by point in this commentary.

CARE: Protocol of a randomised trial evaluating the feasibility of preoperative intentional weight loss to support postoperative recovery in patients with excess weight and colorectal cancer.

AIM: Excess weight increases the risk of morbidity following colorectal cancer surgery. Weight loss may improve morbidity, but it is uncertain whether patients can follow an intensive weight loss intervention while waiting for surgery and there are concerns about muscle mass loss. The aim of this trial is to assess the feasibility of intentional weight loss in this setting and determine progression to a definitive trial. METHODS: CARE is a prospectively registered, multicentre, feasibility, parallel, randomised controlled trial with embedded evaluation and optimisation of the recruitment process. Participants with excess weight awaiting curative colorectal resection for cancer are randomised 1:1 to care as usual or a low-energy nutritionally-replete total diet replacement programme with weekly remote behavioural support by a dietitian. Progression criteria will be based on the recruitment, engagement, adherence, and retention rates. Data will be collected on the 30-day postoperative morbidity, the typical primary outcome of prehabilitation trials. Secondary outcomes will include, among others, length of hospital stay, health-related quality of life, and body composition. Qualitative interviews will be used to understand patients' experiences of and attitudes towards trial participation and intervention engagement and adherence. CONCLUSION: CARE will evaluate the feasibility of intensive intentional weight loss as prehabilitation before colorectal cancer surgery. The results will determine the planning of a definitive trial.

Synthesis and Structural Characterization of Macrocyclic Plasmin Inhibitors.

Two series of macrocyclic plasmin inhibitors with a C-terminal benzylamine group were synthesized. The substitution of the N-terminal phenylsulfonyl group of a previously described inhibitor provided two analogues with sub-nanomolar inhibition constants. Both compounds possess a high selectivity against all other tested trypsin-like serine proteases. Furthermore, a new approach was used to selectively introduce asymmetric linker segments. Two of these compounds inhibit plasmin with Ki values close to 2 nM. For the first time, four crystal structures of these macrocyclic inhibitors could be determined in complex with a Ser195Ala microplasmin mutant. The macrocyclic core segment of the inhibitors binds to the open active site of plasmin without any steric hindrance. This binding mode is incompatible with other trypsin-like serine proteases containing a sterically demanding 99-hairpin loop. The crystal structures obtained experimentally explain the excellent selectivity of this inhibitor type as previously hypothesized.

Organometallic Platinum(II) Photosensitisers that Demonstrate Ligand-Modulated Triplet-Triplet Annihilation Energy Upconversion Efficiencies.

A series of 2-phenylquinoxaline ligands have been synthesised that introduce either CF3 or OCF3 electron-withdrawing groups at different positions of the phenyl ring. These ligands were investigated as cyclometalating reagents for platinum(II) to give neutral complexes of the form [Pt(C^N)(acac)] (in which C^N=cyclometalating ligand; acac=acetyl acetonate). X-ray crystallographic studies on three examples showed that the complexes adopt an approximate square planar geometry. All examples revealed strong Pt-Pt linear contacts of 3.2041(6), 3.2199(3) and 3.2586(2) Å. The highly coloured complexes display efficient visible absorption at 400-500 nm (ϵ ≈5000 M-1  cm-1 ) and orange red photoluminescent characteristics (λem =603-620 nm; Φem ≤37 %), which were subtly tuned by the ligand. Triplet emitting character was confirmed by microsecond luminescence lifetimes and the photogeneration of singlet oxygen with quantum efficiencies up to 57 %. Each complex was investigated as a photosensitiser for triplet-triplet annihilation energy upconversion using 9,10-diphenylanthracene as the annihilator species: a range of good upconversion efficiencies (ΦUC 5.9-14.1 %) were observed and shown to be strongly influenced by the ligand structure in each case.

Inherited MUTYH mutations cause elevated somatic mutation rates and distinctive mutational signatures in normal human cells.

Cellular DNA damage caused by reactive oxygen species is repaired by the base excision repair (BER) pathway which includes the DNA glycosylase MUTYH. Inherited biallelic MUTYH mutations cause predisposition to colorectal adenomas and carcinoma. However, the mechanistic progression from germline MUTYH mutations to MUTYH-Associated Polyposis (MAP) is incompletely understood. Here, we sequence normal tissue DNAs from 10 individuals with MAP. Somatic base substitution mutation rates in intestinal epithelial cells were elevated 2 to 4-fold in all individuals, except for one showing a 31-fold increase, and were also increased in other tissues. The increased mutation burdens were of multiple mutational signatures characterised by C > A changes. Different mutation rates and signatures between individuals are likely due to different MUTYH mutations or additional inherited mutations in other BER pathway genes. The elevated base substitution rate in normal cells likely accounts for the predisposition to neoplasia in MAP. Despite ubiquitously elevated mutation rates, individuals with MAP do not display overt evidence of premature ageing. Thus, accumulation of somatic mutations may not be sufficient to cause the global organismal functional decline of ageing.

An innate IL-25-ILC2-MDSC axis creates a cancer-permissive microenvironment for Apc mutation-driven intestinal tumorigenesis.

Interleukin-25 (IL-25) and group 2 innate lymphoid cells (ILC2s) defend the host against intestinal helminth infection and are associated with inappropriate allergic reactions. IL-33-activated ILC2s were previously found to augment protective tissue-specific pancreatic cancer immunity. Here, we showed that intestinal IL-25-activated ILC2s created an innate cancer-permissive microenvironment. Colorectal cancer (CRC) patients with higher tumor IL25 expression had reduced survival and increased IL-25R-expressing tumor-resident ILC2s and myeloid-derived suppressor cells (MDSCs) associated with impaired antitumor responses. Ablation of IL-25 signaling reduced tumors, virtually doubling life expectancy in an Apc mutation-driven model of spontaneous intestinal tumorigenesis. Mechanistically, IL-25 promoted intratumoral ILC2s, which sustained tumor-infiltrating MDSCs to suppress antitumor immunity. Therapeutic antibody-mediated blockade of IL-25 signaling decreased intratumoral ILC2s, MDSCs, and adenoma/adenocarcinoma while increasing antitumor adaptive T cell and interferon-γ (IFN-γ)-mediated immunity. Thus, the roles of innate epithelium-derived cytokines IL-25 and IL-33 as well as ILC2s in cancer cannot be generalized. The protumoral nature of the IL-25-ILC2 axis in CRC highlights this pathway as a potential therapeutic target against CRC.