Cytosolic serine hydroxymethyltransferase controls lung adenocarcinoma cells migratory ability by modulating AMP kinase activity

Nutrient utilization and reshaping of metabolism in cancer cells is a well-known driver of malignant transformation. Less clear is the influence of the local microenvironment on metastasis formation and choice of the final organ to invade. Here we show that the level of the amino acid serine in the cytosol affects the migratory properties of lung adenocarcinoma (LUAD) cells. Inhibition of serine or glycine uptake from the extracellular milieu, as well as knockdown of the cytosolic one-carbon metabolism enzyme serine hydroxymethyltransferase (SHMT1), abolishes migration. Using rescue experiments with a brain extracellular extract, and direct measurements, we demonstrate that cytosolic serine starvation controls cell movement by increasing reactive oxygen species formation and decreasing ATP levels, thereby promoting activation of the AMP sensor kinase (AMPK) by phosphorylation. Activation of AMPK induces remodeling of the cytoskeleton and finally controls cell motility. These results highlight that cytosolic serine metabolism plays a key role in controlling motility, suggesting that cells are able to dynamically exploit the compartmentalization of this metabolism to adapt their metabolic needs to different cell functions (movement vs. proliferation). We propose a model to explain the relevance of serine/glycine metabolism in the preferential colonization of the brain by LUAD cells and suggest that the inhibition of serine/glycine uptake and/or cytosolic SHMT1 might represent a successful strategy to limit the formation of brain metastasis from primary tumors, a major cause of death in these patients

The emerging role of amino acids of the brain microenvironment in the process of metastasis formation

Brain metastases are the most severe clinical manifestation of aggressive tumors. Melanoma, breast, and lung cancers are the types that prefer the brain as a site of metastasis formation, even if the reasons for this phenomenon still remain to be clarified. One of the main characteristics that makes a cancer cell able to form metastases in the brain is the ability to interact with the endothelial cells of the microvasculature, cross the blood–brain barrier, and metabolically adapt to the nutrients available in the new microenvironment. In this review, we analyzed what makes the brain a suitable site for the development of metastases and how this microenvironment, through the continuous release of neurotransmitters and amino acids in the extracellular milieu, is able to support the metabolic needs of metastasizing cells. We also suggested a possible role for amino acids released by the brain through the endothelial cells of the blood–brain barrier into the bloodstream in triggering the process of extravasation/invasion of the brain parenchyma

Beyond the barrier: the immune-inspired pathways of tumor extravasation

Abstract Extravasation is a fundamental step in the metastatic journey, where cancer cells exit the bloodstream and breach the endothelial cell barrier to infiltrate target tissues. The tactics cancer cells employ are sophisticated, closely reflecting those used by the immune system for tissue surveillance. Remarkably, tumor cells have been observed to form distinct associations or clusters with immune cells where neutrophils stand out as particularly crucial partners. These interactions are not accidental; they are critical for cancer cells to exploit the immune functions of neutrophils and successfully extravasate. In another strategy, tumor cells mimic the behavior and characteristics of immune cells. They release a suite of inflammatory mediators, which under normal circumstances, guide the processes of endothelium reshaping and facilitate the entry and movement of immune cells within tissues. In this review, we offer a new perspective on the tactics employed by cancer cells to extravasate and infiltrate target tissues. We delve into the myriad mechanisms that tumor cells borrow, adapt, and refine from the immune playbook. Video Abstrac

Targeting the Grb2 cSH3 domain: design, synthesis and biological evaluation of the first series of modulators

Growth factor receptor bound protein 2 (Grb2) is an adaptor protein featured by a nSH3-SH2-cSH3 domains. Grb2 finely regulates important cellular pathways such as growth, proliferation and metabolism and a minor lapse of this tight control may totally change the entire pathway to the oncogenic. Indeed, Grb2 is found overexpressed in many tumours type. Consequently, Grb2 is an attractive therapeutic target for the development of new anticancer drug. Herein, we reported the synthesis and the biological evaluation of a series of Grb2 inhibitors, developed starting from a hit-compound already reported by this research unit. The newly synthesized compounds were evaluated by kinetic binding experiments, and the most promising derivatives were assayed in a short panel of cancer cells. Five of the newly synthesized derivatives proved to be able to bind the targeted protein with valuable inhibitory concentration in one-digit micromolar concentration. The most active compound of this series, derivative 12, showed an inhibitory concentration of about 6 μM for glioblastoma and ovarian cancer cells, and an IC50 of 1.67 for lung cancer cell. For derivative 12, the metabolic stability and the ROS production was also evaluated. The biological data together with the docking studies led to rationalize an early structure activity relationship

Cytosolic localization and in vitro assembly of human de novo thymidylate synthesis complex

De novo thymidylate synthesis is a crucial pathway for normal and cancer cells. Deoxythymidine monophosphate (dTMP) is synthesized by the combined action of three enzymes: serine hydroxymethyltransferase (SHMT), dihydrofolate reductase (DHFR) and thymidylate synthase (TYMS), with the latter two being targets of widely used chemotherapeutics such as antifolates and 5-fluorouracil. These proteins translocate to the nucleus after SUMOylation and are suggested to assemble in this compartment into the thymidylate synthesis complex (dTMP-SC). We report the intracellular dynamics of the complex in cancer cells by in situ proximity ligation assay, showing that it is also detected in the cytoplasm. This result indicates that the role of the dTMP-SC assembly may go beyond dTMP synthesis. We have successfully assembled the dTMP synthesis complex in vitro, employing tetrameric SHMT1 and a bifunctional chimeric enzyme comprising human TYMS and DHFR. We show that the SHMT1 tetrameric state is required for efficient complex assembly, indicating that this aggregation state is evolutionarily selected in eukaryotes to optimize protein-protein interactions. Lastly, our results on the activity of the complete thymidylate cycle in vitro, may provide a useful tool to develop drugs targeting the entire complex instead of the individual components

Fludarabine, cyclophosphamide and lenalidomide in patients with relapsed/refractory chronic lymphocytic leukemia. A multicenter phase I–II GIMEMA trial

The activity and safety of a regimen combining lenalidomide with fludarabine and cyclophosphamide (FC) was investigated in patients with relapsed/refractory (R/R) chronic lymphocytic leukemia (CLL). Treatment consisted of six monthly courses of the FC regimen combined with 14 days of lenalidomide given at the starting dose of 2.5 mg during course 1. The maximum tolerated dose of lenalidomide was 5 mg. Forty patients were assessed for response, 66% were IGHV unmutated, 45% showed deletion 11q or 17p. The overall response and complete remission rates were 62.5% and 22.5%, respectively, the median progression-free and overall survival (OS) were 19 and 45 months, respectively. Grade 3–4 granulocytopenia was observed in 65% of cases, severe infections in 7.5%, the lenalidomide-related toxicity was mild. In conclusion, the results of this study demonstrate that low-dose lenalidomide associated with the FC schedule is an effective treatment for R/R patients with CLL, associated with an acceptable safety profile

A SINGLE-ARM MULTI-CENTER TRIAL OF BENDAMUSTINE GIVEN WITH OFATUMUMAB (BENDOFA) IN PATIENTS WITH REFRACTORY OR RELAPSED CHRONIC LYMPHOCYTIC LEUKEMIA. GIMEMA CLL0809 PROTOCOL

Background B-cell chronic lymphocytic leukemia is a clinically heterogeneous disease; some patients rapidly progress and die within a few years of diagnosis, whereas others have a long life expectancy with minimal or no treatment. Telomere length and telomerase levels have been proposed as prognostic factors; however, very few cases have been characterized for both parameters and no study has analyzed the prognostic value of the telomere/telomerase profile.Design and Methods One hundred and seventy-three cases of chronic lymphocytic leukemia were characterized for telomere lengths and telomerase levels by real-time polymerase chain reaction. Data were correlated with established prognostic markers, IGVH mutational status and chromosomal aberrations, and clinical outcome.Results Telomere lengths were inversely correlated with telomerase levels (rs= -0.213; P=0.012), and most of the cases of chronic lymphocytic leukemia with high levels (above median) of telom-erase had short (below median) telomeres (P=0.0001). Telomerase levels were higher and telomeres were shorter in unmutated IGVH cases than in mutated IGVH ones (P<0.0001). Chronic lymphocytic leukemias with 11q, 17p deletion or 12 trisomy had significantly higher levels of telomerase and shorter telomeres than those with no chromosomal aberration or the sole 13q deletion (P<0.001). Telomere length/telomerase level profiles identified subgroups of patients with different clinical outcomes (P<0.0001), even within the subsets of chronic lym-phocytic leukemia defined by IGVH mutational status or chromosomal aberrations. Short telomere/high telomerase profile was independently associated with more rapid disease progression.Conclusions Comprehensive analyses of telomeres, telomerase, chromosomal aberrations, and IGVH muta-tional status delineate groups of chronic lymphocytic leukemias with distinct biological characteristics and clinical outcomes. The telomere/telomerase profile may be particularly useful in refining the prognosis of chronic lymphocytic leukemia patients with mutated IGVH and no high-risk chromosomal aberrations

Efficacy of Front-Line Ibrutinib and Rituximab Combination and the Impact of Treatment Discontinuation in Unfit Patients with Chronic Lymphocytic Leukemia: Results of the Gimema LLC1114 Study

SIMPLE SUMMARY: This prospective, multicenter study aimed to investigate the efficacy and safety of a front-line treatment with the ibrutinib and rituximab combination in 146 unfit patients with chronic lymphocytic leukemia (CLL). We observed an OR, CR, and 48-month PFS rates of 87%, 22.6%, and 77%, respectively. Responses with undetectable MRD were observed in 6.2% of all patients and 27% of CR patients. TP53 disruption and B-symptoms revealed a significant and independent impact on PFS. The 48-month cumulative treatment discontinuation rate due to adverse events in this patient population was 29.1%. It was significantly higher in male patients, in patients aged ≥70 years, and in those managed at centers that enrolled less than five patients. In conclusion, the ibrutinib and rituximab combination was an effective front-line treatment for unfit patients with CLL. However, a high rate of treatment discontinuations due to adverse events was observed in this unfit population. ABSTRACT: The GIMEMA group investigated the efficacy, safety, and rates of discontinuations of the ibrutinib and rituximab regimen in previously untreated and unfit patients with chronic lymphocytic leukemia (CLL). Treatment consisted of ibrutinib, 420 mg daily, and until disease progression, and rituximab (375 mg/sqm, given weekly on week 1–4 of month 1 and day 1 of months 2–6). This study included 146 patients with a median age of 73 years, with IGHV unmutated in 56.9% and TP53 disrupted in 22.2%. The OR, CR, and 48-month PFS rates were 87%, 22.6%, and 77%, respectively. Responses with undetectable MRD were observed in 6.2% of all patients and 27% of CR patients. TP53 disruption (HR 2.47; p = 0.03) and B-symptoms (HR 2.91; p = 0.02) showed a significant and independent impact on PFS. The 48-month cumulative rates of treatment discontinuations due to disease progression (DP) or adverse events (AEs) were 5.6% and 29.1%, respectively. AEs leading more frequently to treatment discontinuation were atrial fibrillation in 8% of patients, infections in 8%, and non-skin cancers in 6%. Discontinuation rates due to AEs were higher in male patients (HR: 0.46; p = 0.05), patients aged ≥70 years (HR 5.43, p = 0.0017), and were managed at centers that enrolled <5 patients (HR 5.1, p = 0.04). Patients who discontinued ibrutinib due to an AE showed a 24-month next treatment-free survival rate of 63%. In conclusion, ibrutinib and rituximab combination was an effective front-line treatment with sustained disease control in more than half of unfit patients with CLL. Careful monitoring is recommended to prevent and manage AEs in this patient population