The loss of E-cadherin, an epithelial cell adhesion molecule, has been implicated in metastasis by mediating the epithelial–mesenchymal transition, which promotes invasion and migration of cancer cells. However, recent studies have demonstrated that E-cadherin supports the survival and proliferation of metastatic cancer cells. Here, we identified a metabolic role for E-cadherin in breast cancer by upregulating the de novo serine synthesis pathway (SSP). The upregulated SSP provided metabolic precursors for biosynthesis and resistance to oxidative stress, enabling E-cadherin+ breast cancer cells to achieve faster tumor growth and enhanced metastases. Inhibition of phosphoglycerate dehydrogenase, a rate-limiting enzyme in the SSP, significantly and specifically hampered proliferation of E-cadherin+ breast cancer cells and rendered them vulnerable to oxidative stress, inhibiting their metastatic potential. These findings reveal that E-cadherin reprograms cellular metabolism, promoting tumor growth and metastasis of breast cancers. Significance: E-Cadherin promotes the progression and metastasis of breast cancer by upregulating the de novo serine synthesis pathway, offering promising targets for inhibiting tumor growth and metastasis in E-cadherin–expressing tumors.

Skeletal muscle mass is decreased under a wide range of pathologic conditions. In particular, chemotherapy is well known for inducing muscle loss and atrophy. Previous studies using tonsil-derived mesenchymal stem cells (T-MSCs) or a T-MSC-conditioned medium showed effective recovery of total body weight in the chemotherapy-preconditioned bone marrow transplantation mouse model. This study investigated whether extracellular vesicles of T-MSCs, such as exosomes, are a key player in the recovery of body weight and skeletal muscle mass in chemotherapy-treated mice. T-MSC exosomes transplantation significantly decreased loss of total body weight and muscle mass in the busulfan-cyclophosphamide conditioning regimen in BALB/c recipient mice containing elevated serum activin A. Additionally, T-MSC exosomes rescued impaired C2C12 cell differentiation in the presence of activin A in vitro. We found that T-MSC exosomes possess abundant miR-145-5p, which targets activin A receptors, ACVR2A, and ACVR1B. Indeed, T-MSC exosomes rescue muscle atrophy both in vivo and in vitro via miR-145-5p dependent manner. These results suggest that T-MSC exosomes have therapeutic potential to maintain or improve skeletal muscle mass in various activin A elevated pathologic conditions.

Exosomes are a group of small membranous vesicles that are shed into the extracellular environment by tumoral or non-tumoral cells and contribute to cellular communication by delivering micro RNAs (miRNAs). In this study, we aimed to evaluate the role of exosomal miRNAs from colorectal cancer cell lines in tumorigenesis, by affecting cancer-associated fibroblasts (CAFs), which are vital constituents of the tumor microenvironment. To analyze the effect of exosomal miRNA on the tumor microenvironment, migration of the monocytic cell line THP-1 was evaluated via Transwell migration assay using CAFs isolated from colon cancer patients. The migration assay was performed with CAFs ± CCL7-blocking antibody and CAFs that were treated with exosomes isolated from colon cancer cell lines. To identify the associated exosomal miRNAs, miRNA sequencing and quantitative reverse transcription polymerase chain reaction were performed. The migration assay revealed that THP-1 migration was decreased in CCL7-blocking antibody-expressing and exosome-treated CAFs. Colon cancer cell lines contained miRNA let-7d in secreted exosomes targeting the chemokine CCL7. Exosomes from colorectal cancer cell lines affected CCL7 secretion from CAFs, possibly via the miRNA let-7d, and interfered with the migration of CCR2+ monocytic THP-1 cellsin vitro.

The Fanconi anemia (FA) DNA repair pathway is required for the repair of DNA interstrand cross-links (ICLs). ICLs are caused by genotoxins, such as chemotherapeutic agents or reactive aldehydes. Inappropriately repaired ICLs contribute to hematopoietic stem cell (HSC) failure and tumorigenesis. While endogenous acetaldehyde and formaldehyde are known to induce HSC failure and leukemia in FA patients, the effects of other toxic metabolites on FA pathogenesis have not been systematically investigated. Using a metabolism-focused CRISPR screen, we found a synthetically lethal interaction between ALDH9A1 and the deficiency of the FA pathway. Combined deficiency of ALDH9A1 and FANCD2 causes genomic instability, apoptosis, and decreased hematopoietic colony formation. Fanca−/−Aldh9a1−/− mice exhibited an increased incidence of ovarian tumors. A suppressor CRISPR screen revealed that the loss of ATP13A3, a polyamine transporter, resulted in improved survival of FANCD2−/−ALDH9A1−/− cells. These findings nominate high intracellular polyamines and the resulting 3-aminopropanal and acrolein as sources of endogenous DNA damage in patients with FA.

Respiratory syncytial virus (RSV) can cause serious respiratory illnesses such as pneumonia, asthma, and bronchiolitis in infants and elderly or immunocompromised individuals. An RSV vaccine has yet to be developed; only prophylactic anti-RSV antibody is commercially available. So, we investigated whether our vaccine candidate is able to induce type 1 CD4+ T helper (Th1), CD8+ T-cell responses, and protective immunity without vaccine-enhanced disease (VED) against RSV. We used RSV G protein fragment (Gcf A) with recombinant baculovirus capable of expressing the RSV M2 protein (Bac M2) as a vaccine candidate, and injected this vaccine (Gcf A/Bac M2) intramuscularly, and challenged with RSV intranasally into mice. Enzyme-linked immunosorbent assay, flow cytometry, plaque assay, and weight measurement were performed to confirm humoral immunity, cellular immunity, and protective immunity. The Gcf A/Bac M2 formulation induced a stronger IgG response to Gcf A than Gcf A inoculation alone, and the ratio of IgG1/IgG2a indicated that the responses shifted predominantly to Th1. In addition, both RSV G-specific Th1 responses and RSV M2-specific CD8+ T-cell responses were induced, and G protein-associated eosinophilic infiltration was suppressed compared to the control group. Moreover, the Gcf A/Bac M2 group showed effective protection after an RSV challenge. Bac M2 could serve as a vaccine with intrinsic adjuvant activity, and the Gcf A/Bac M2 shows promise as a vaccine candidate for inducing protective immunity without inciting VED.

Chronic alcohol use can cause pancytopenia and diminished immune responses against pathogens. However, its underlying molecular mechanisms remain unclear. Furthermore, whether chronic alcohol consumption directly induces inflammation in human hematopoietic stem progenitor cells (HSPCs) or whether it affects aging hematopoiesis differently is unknown. To examine how chronic alcohol use influences HSPCs, we performed single-cell RNA-seq in murine and human HSPCs and single-cell ATAC-seq in aged murine HSPCs following alcohol exposure. In the native murine bone marrow, chronic alcohol exposure primed HSPCs to differentiate into myeloid cells and to exhibit heightened inflammation, DNA damage, and epigenetic reactivation of transposable elements (TEs) in an age-dependent manner. Alcohol-exposed aged long-term hematopoietic stem cells (LT-HSCs) displayed increased chromatin accessibility at TE-containing loci correlated with aberrant TE transcription. This transposon derepression was associated with the accumulation of dsRNAs in aged bone marrow cells, and activation of innate immune pathways, perpetuating HSC inflammaging. Furthermore, we identified two epigenetically distinct LT-HSC clusters, LT-HSC1 and LT-HSC2, with the LT-HSC2 cluster expanding in response to chronic alcohol consumption, resembling activated HSCs. In xenotransplanted human HSPCs, chronic alcohol feeding resulted in a significant myeloid bias, heightened inflammation, upregulation of double-stranded RNA (dsRNA) sensors, activation of type I interferon responses, and increased expression of endogenous retroviruses. Despite these molecular alterations, we did not observe a decrease in long-term repopulation capacity in either human or murine HSCs. This suggests that HSC function may recover following alcohol cessation. However, previous chronic alcohol exposures imprint murine HSPCs to exhibit long-term myeloid bias and reduced cell cycle entry upon bacterial LPS challenge. Our data illuminate potential interactions between alcohol and aging that can reinforce inflammaging and epigenetic dysregulation in HSPCs. Keypoints: Aging perpetuates alcohol-induced myeloid bias, inflammation, DNA damage, and TE upregulation in murine HSPCs Prior chronic alcohol consumption does not affect long-term repopulation but causes persistent myeloid bias and inefficient stress responses after LPS challenge Chronic alcohol consumption alters chromatin accessibility in TE-overlapping regions Chronic alcohol consumption promotes myeloid bias, inflammation, and upregulation of endogenous retroviruses in xenotransplanted human HSPCs. Graphical