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Understanding cellular metabolism holds immense potential for developing new classes of therapeutics that target metabolic pathways in cancer. Metabolic pathways are altered in bulk neoplastic cells in comparison to normal tissues. However, carcinoma cells within tumors are heterogeneous, and tumor-initiating cells (TICs) are important therapeutic targets that have remained metabolically uncharacterized. To understand their metabolic alterations, we performed metabolomics and metabolite tracing analyses, which revealed that TICs have highly elevated methionine cycle activity and transmethylation rates that are driven by MAT2A. High methionine cycle activity causes methionine consumption to far outstrip its regeneration, leading to addiction to exogenous methionine. Pharmacological inhibition of the methionine cycle, even transiently, is sufficient to cripple the tumor-initiating capability of these cells. Methionine cycle flux specifically influences the epigenetic state of cancer cells and drives tumor initiation. Methionine cycle enzymes are also enriched in other tumor types, and MAT2A expression impinges upon the sensitivity of certain cancer cells to therapeutic inhibition.Elevated activity of the methionine cycle is essential for cancer stem cell tumorigenesis and represents a therapeutic vulnerability.

Severe infections are a major stress on haematopoiesis, where the consequences for haematopoietic stem cells (HSCs) have only recently started to emerge. HSC function critically depends on the integrity of complex bone marrow (BM) niches; however, what role the BM microenvironment plays in mediating the effects of infection on HSCs remains an open question. Here, using a murine model of malaria and combining single-cell RNA sequencing, mathematical modelling, transplantation assays and intravital microscopy, we show that haematopoiesis is reprogrammed upon infection, whereby the HSC compartment turns over substantially faster than at steady-state and HSC function is drastically affected. Interferon is found to affect both haematopoietic and mesenchymal BM cells and we specifically identify a dramatic loss of osteoblasts and alterations in endothelial cell function. Osteo-active parathyroid hormone treatment abolishes infection-triggered HSC proliferation and—coupled with reactive oxygen species quenching—enables partial rescuing of HSC function.Haltalli et al. show that Plasmodium berghei infection induces interferon release, and affects haematopoietic stem cell proliferation and function, as well as osteoblasts and vascular integrity, in the bone marrow niche.

Recent efforts have attempted to convert non-blood cells into hematopoietic stem cells (HSCs) with the goal of generating blood lineages de novo . Here we show that hematopoietic transcription factors Scl , Lmo2 , Runx1 and Bmi1 can convert a developmentally distant lineage (fibroblasts) into ‘induced hematopoietic progenitors’ (iHPs). Functionally, iHPs generate acetylcholinesterase + megakaryocytes and phagocytic myeloid cells in vitro and can also engraft immunodeficient mice, generating myeloerythoid and B-lymphoid cells for up to 4 months in vivo . Molecularly, iHPs transcriptionally resemble native Kit + hematopoietic progenitors. Mechanistically, reprogramming factor Lmo2 implements a hematopoietic programme in fibroblasts by rapidly binding to and upregulating the Hhex and Gfi1 genes within days. Moreover the reprogramming transcription factors also require extracellular BMP and MEK signalling to cooperatively effectuate reprogramming. Thus, the transcription factors that orchestrate embryonic hematopoiesis can artificially reconstitute this programme in developmentally distant fibroblasts, converting them into engraftable blood progenitors. Direct reprogramming of closely-related lineages can generate hematopoietic stem cells. Here, the authors show hematopoietic transcription factors Scl, Lmo2, Runx1 and Bmi1 can reprogram fibroblasts into induced hematopoietic progenitors (iHPs), which are engraftable blood progenitors.

In the version of this article originally published, there is an error in Fig. 5a. Originally, ‘MAT2A’ appeared between ‘Methionine’ and ‘Homocysteine’. ‘MAT2A’ should have been ‘MTR’. The error has been corrected in the PDF and HTML versions of this article.

Severe infections are a major source of stress on haematopoiesis, where consequences for haematopoietic stem cells (HSCs) have only recently started to emerge. HSC function critically depends on the integrity of complex bone marrow niches, which have been shown to be altered during ageing and haematopoietic malignancies. Whether the bone marrow (BM) microenvironment plays a role in mediating the effects of infection on HSCs remains an open question. Here we used an murine model of malaria coupled with intravital microscopy, single cell RNA-Seq, mathematical modelling and transplantation assays to obtain a quantitative understanding of the proliferation dynamics of haematopoietic stem and progenitor cells (HSPCs) during Plasmodium infection. We uncovered that during Plasmodium infection the HSC compartment turns over significantly faster than in steady state, and that a global interferon response and loss of functional HSCs are linked to alterations in BM endothelium function and osteoblasts number. Interventions that targeted osteoblasts uncoupled HSC proliferation and function, thus opening up new avenues for therapeutic interventions that may improve the health of survivors of severe infections.

Background Genome-wide methylation of cytosine can be modulated in the presence of TET and thymine DNA glycosylase (TDG) enzymes. TET is able to oxidise 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC). TDG can excise the oxidative products 5fC and 5caC, initiating base excision repair. These modified bases are stable and detectable in the genome, suggesting that they could have epigenetic functions in their own right. However, functional investigation of the genome-wide distribution of 5fC has been restricted to cell culture-based systems, while its in vivo profile remains unknown. Results Here, we describe the first analysis of the in vivo genome-wide profile of 5fC across a range of tissues from both wild-type and Tdg -deficient E11.5 mouse embryos. Changes in the formylation profile of cytosine upon depletion of TDG suggest TET/TDG-mediated active demethylation occurs preferentially at intron-exon boundaries and reveals a major role for TDG in shaping 5fC distribution at CpG islands. Moreover, we find that active enhancer regions specifically exhibit high levels of 5fC, resulting in characteristic tissue-diagnostic patterns, which suggest a role in embryonic development. Conclusions The tissue-specific distribution of 5fC can be regulated by the collective contribution of TET-mediated oxidation and excision by TDG. The in vivo profile of 5fC during embryonic development resembles that of embryonic stem cells, sharing key features including enrichment of 5fC in enhancer and intragenic regions. Additionally, by investigating mouse embryo 5fC profiles in a tissue-specific manner, we identify targeted enrichment at active enhancers involved in tissue development.

Mutations in the gene encoding the fused in sarcoma (FUS) protein are responsible for ~3% of familial amyotrophic lateral sclerosis (ALS) and <1% of sporadic ALS (ALS- FUS ). Descriptions of the associated neuropathology are few and largely restricted to individual case reports. To better define the neuropathology associated with FUS mutations, we have undertaken a detailed comparative analysis of six cases of ALS- FUS that include sporadic and familial cases, with both juvenile and adult onset, and with four different FUS mutations. We found significant pathological heterogeneity among our cases, with two distinct patterns that correlated with the disease severity and the specific mutation. Frequent basophilic inclusions and round FUS-immunoreactive (FUS-ir) neuronal cytoplasmic inclusions (NCI) were a consistent feature of our early-onset cases, including two with the p.P525L mutation. In contrast, our late-onset cases that included two with the p.R521C mutation had tangle-like NCI and numerous FUS-ir glial cytoplasmic inclusions. Double-labeling experiments demonstrated that many of the glial inclusions were in oligodendrocytes. Comparison with the neuropathology of cases of frontotemporal lobar degeneration with FUS-ir pathology showed significant differences and suggests that FUS mutations are associated with a distinct pathobiology.

Background Achieving adequate, timely, and diverse trial enrollment remains a major challenge in clinical research. Insufficiently diverse patient representation compromises the generalizability of clinical trial findings and remains a persistent issue in oncology. Navigation services may help patients learn about clinical trials, identify and overcome barriers, and progress through the care pathway to trial enrollment and retention. Methods We implemented a patient navigation program to support diverse enrollment and retention of patients in cancer clinical trials; the proximal outcomes were receipt of financial navigation and trial interest. The study was conducted from July 2023 to July 2024 at two demographically diverse health care settings: a university‐based tertiary healthcare system and an integrated safety‐net healthcare system. Evaluation was guided by the Reach, Effectiveness, Adoption, Implementation, and Maintenance framework and incorporated programmatic data, structured surveys of patients and staff, and qualitative patient interviews. Results The program navigated 429 oncology patients (52% female, 28% Hispanic/Latino (HL), and 16% non‐HL Black). Compared to the underlying patient population of the clinical settings, program participants were more likely to be Hispanic (31% vs. 21%; p < 0.01), female (52% vs. 48%; p = 0.01) and from a minority race (30% vs. 24%, p ≤ 0.01). Within the population who were successfully contacted, 325 of 408 (92%) patients already enrolled in a trial received financial navigation to help with trial retention. Among the remaining 83 patients not enrolled in a cancer clinical trial at the time of referral, 39 (47%) expressed interest in participating in a clinical trial in thefuture. Conclusion A patient navigation program to influence enrollment and retention of diverse patients into trials was feasible to implement, highly acceptable to patients, and reached a priority population of patients generally underrepresented in cancer clinical trials. Further research into the effect of navigation on trial enrollment and retention is warranted.

Background The Dallas Metastatic Cancer Study is a clinical database established to examine local trends associated with the diagnosis and treatment of de novo metastatic breast cancer and identify factors for further evaluation. Clinical characteristics of patients with de novo metastatic breast cancer are often underreported in the literature. Methods We report data from 2010 to 2021 for patients with de novo metastatic breast cancer along with the impact of clinical variables such as age, BMI, race and ethnicity, insurance status, hypertension, diabetes, and site of metastasis with survival analysis with respect to subtype. Results Black race (HR 2.07, 95% CI 1.56–2.74), public insurance (HR 1.64, 95% CI 1.23–2.18), no insurance (HR 1.69, 95% CI 1.24–2.31), hypertension (HR 1.50, 95% CI 1.18–1.91), diabetes (HR 1.69, 95% CI 1.24–2.31), and visceral metastases including brain (HR 1.68, 95% CI 1.20–2.36), liver (HR 1.80, 95% CI 1.40–2.30), and lung (HR 1.50, 95% CI 1.17–1.92) were associated with increased mortality and remained significant when controlled for subtype. In the multivariate analysis, diabetes (HR 1.74, 95% CI 1.22–2.49) and presence of liver metastases (HR 1.97, 95% CI 1.43–2.49) remained independently associated with decreased overall survival regardless of subtype and other variables. Patients diagnosed at 40 and younger were less likely to have hypertension and diabetes, more likely to be Hispanic, and showed distinct subtype distributions compared to those diagnosed at older ages. Conclusions Future work will focus on these associations at the patient level to identify targets for intervention. Plain language summary The Dallas Metastatic Cancer Study aims to better understand metastatic breast cancer by examining local trends in diagnosis and treatment. The study analyzed data from 2010 to 2021 and specifically focused on patients with a metastatic breast cancer diagnosis at first presentation. The study evaluated how factors such as age, BMI, race, insurance status, and co-existing medical conditions like hypertension and diabetes affected survival. The results show that Black patients, those with public or no insurance, those with specific metastases (i.e., liver, brain, lung) had worse survival outcomes. These outcomes underscore the areas where targeted interventions could improve patient outcomes. Chang, Cao et al. examine local trends associated with the diagnosis and treatment of de novo metastatic breast cancer. Findings show that black race, hypertension, diabetes, as well as the presence of visceral metastases are associated with a worse prognosis.

Background C-terminal Src kinase (Csk) and Csk-homologous kinase (Chk) are the major endogenous inhibitors of Src-family kinases (SFKs). They employ two mechanisms to inhibit SFKs. First, they phosphorylate the C-terminal tail tyrosine which stabilizes SFKs in a closed inactive conformation by engaging the SH2 domain in cis . Second, they employ a non-catalytic inhibitory mechanism involving direct binding of Csk and Chk to the active forms of SFKs that is independent of phosphorylation of their C-terminal tail. Csk and Chk are co-expressed in many cell types. Contributions of the two mechanisms towards the inhibitory activity of Csk and Chk are not fully clear. Furthermore, the determinants in Csk and Chk governing their inhibition of SFKs by the non-catalytic inhibitory mechanism are yet to be defined. Methods We determined the contributions of the two mechanisms towards the inhibitory activity of Csk and Chk both in vitro and in transduced colorectal cancer cells. Specifically, we assayed the catalytic activities of Csk and Chk in phosphorylating a specific peptide substrate and a recombinant SFK member Src. We employed surface plasmon resonance spectroscopy to measure the kinetic parameters of binding of Csk, Chk and their mutants to a constitutively active mutant of the SFK member Hck. Finally, we determined the effects of expression of recombinant Chk on anchorage-independent growth and SFK catalytic activity in Chk-deficient colorectal cancer cells. Results Our results revealed Csk as a robust enzyme catalysing phosphorylation of the C-terminal tail tyrosine of SFKs but a weak non-catalytic inhibitor of SFKs. In contrast, Chk is a poor catalyst of SFK tail phosphorylation but binds SFKs with high affinity, enabling it to efficiently inhibit SFKs with the non-catalytic inhibitory mechanism both in vitro and in transduced colorectal cancer cells. Further analyses mapped some of the determinants governing this non-catalytic inhibitory mechanism of Chk to its kinase domain. Conclusions SFKs are activated by different upstream signals to adopt multiple active conformations in cells. SFKs adopting these conformations can effectively be constrained by the two complementary inhibitory mechanisms of Csk and Chk. Furthermore, the lack of this non-catalytic inhibitory mechanism accounts for SFK overactivation in the Chk-deficient colorectal cancer cells.