Lysyl oxidase inhibition in primary myelofibrosis: A renewed strategy

Prognostic significance of LOXL2 enzyme activity in primary myelofibrosis

Primary myelofibrosis (PMF) is characterized by bone marrow fibrosis, but the underlying molecular mechanisms remain incompletely understood. Here, we investigated the role of lysyl oxidase-like 2 (LOXL2), an enzyme involved in extracellular matrix remodeling, in PMF pathogenesis. Analysis of bone marrow cells from PMF patients revealed significantly elevated LOXL2 mRNA expression compared to healthy controls, which was further validated using 2 independent Gene Expression Omnibus datasets (GSE26049 and GSE12234). Serum LOXL2 protein levels were markedly increased in PMF patients (n = 38) compared to controls (n = 15) (P < .01), accompanied by significantly enhanced enzymatic activity (P < .05). Clinical analysis demonstrated that high LOXL2 enzyme activity correlated with adverse clinical features, including higher risk scores in both International Prognostic Scoring System (P = .029) and Dynamic International Prognostic Scoring System (P = .012) systems, and increased peripheral blood blast percentages (≥1%, P = .019). Notably, elevated LOXL2 enzyme activity emerged as an independent adverse prognostic factor in multivariate analysis. Gene set enrichment analysis revealed LOXL2's association with multiple biological processes, including extracellular matrix remodeling, inflammatory responses, and JAK-STAT signaling pathways. Using CellMiner drug prediction analysis, we identified several FDA-approved drugs, particularly kinase inhibitors, as potential LOXL2-targeting therapeutics. Our findings demonstrate LOXL2's critical role in PMF pathogenesis and suggest its potential as both a prognostic marker and therapeutic target in PMF treatment.

Research progress of megakaryocytes and platelets in lung injury

The lung is an important site of extramedullary platelet formation, and megakaryocytes in the lung participate in immune responses in addition to platelet production. In acute lung injury and chronic lung injury, megakaryocytes and platelets play a promoting or protective role through different mechanisms. The authors reviewed the role of megakaryocytes and platelets in common clinical lung injuries with different course of disease and different pathogenic factors in order to provide new thinking for the diagnosis and treatment of lung injuries.

A complex interplay of intra- and extracellular factors regulates the outcome of fetal- and adult-derived MLL-rearranged leukemia

Infant and adult MLL1/KMT2A-rearranged (MLLr) leukemia represents a disease with a dismal prognosis. Here, we present a functional and proteomic characterization of in utero-initiated and adult-onset MLLr leukemia. We reveal that fetal MLL::ENL-expressing lymphomyeloid multipotent progenitors (LMPPs) are intrinsically programmed towards a lymphoid fate but give rise to myeloid leukemia in vivo, highlighting a complex interplay of intra- and extracellular factors in determining disease subtype. We characterize early proteomic events of MLL::ENL-mediated transformation in fetal and adult blood progenitors and reveal that whereas adult pre-leukemic cells are mainly characterized by retained myeloid features and downregulation of ribosomal and metabolic proteins, expression of MLL::ENL in fetal LMPPs leads to enrichment of translation-associated and histone deacetylases signaling proteins, and decreased expression of inflammation and myeloid differentiation proteins. Integrating the proteome of pre-leukemic cells with their secretome and the proteomic composition of the extracellular environment of normal progenitors highlights differential regulation of Igf2 bioavailability, as well as of VLA-4 dimer and its ligandome, upon initiation of fetal- and adult-origin leukemia, with implications for human MLLr leukemia cells' ability to communicate with their environment through granule proteins. Our study has uncovered opportunities for targeting ontogeny-specific proteomic vulnerabilities in in utero-initiated and adult-onset MLLr leukemia.

Turner syndrome with primary myelofibrosis, cirrhosis and ovarian cystic mass: A case report

BACKGROUND

Turner syndrome (TS) with leukemia is a complicated clinical condition. The clinical course and outcome of these patients are poor, so the treatment and prognosis of TS with hematological malignancies deserve our attention.

CASE SUMMARY

Here, we report a case of a 20-year-old woman diagnosed with TS, primary myelofibrosis (PMF), cirrhosis, and an ovarian cystic mass. This is the first report on the coexistence of TS and PMF with the MPL and SH2B3 mutations. The patient was diagnosed with cirrhosis of unknown cause, splenomegaly and severe gastroesophageal varices. Additionally, an ovarian cystic mass caused the patient to appear pregnant. The patient was treated with the JAK2 inhibitor-ruxolitinib according to peripheral blood cells, although myelofibrosis was improved, the splenomegaly did not reduce. Moreover, hematemesis and melena occasionally occurred.

CONCLUSION

Ruxolitinib may clearly reduce splenomegaly. Though myelofibrosis was improved, cirrhosis and splenomegaly in this case continued to worsen. Effective treatment should be discussed.

Lysyl-Oxidase Dependent Extracellular Matrix Stiffness in Hodgkin Lymphomas: Mechanical and Topographical Evidence

PURPOSE

The biochemical composition and architecture of the extracellular matrix (ECM) is known to condition development and invasiveness of neoplasms. To clarify this point, we analyzed ECM stiffness, collagen cross-linking and anisotropy in lymph nodes (LN) of Hodgkin lymphomas (HL), follicular lymphomas (FL) and diffuse large B-cell lymphomas (DLBCL), compared with non-neoplastic LN (LDN).

METHODS AND RESULTS

We found increased elastic (Young's) modulus in HL and advanced FL (grade 3A) over LDN, FL grade 1-2 and DLBCL. Digital imaging evidenced larger stromal areas in HL, where increased collagen cross-linking was found; in turn, architectural modifications were documented in FL3A by scanning electron microscopy and enhanced anisotropy by polarized light microscopy. Interestingly, HL expressed high levels of lysyl oxidase (LOX), an enzyme responsible for collagen cross-linking. Using gelatin scaffolds fabricated with a low elastic modulus, comparable to that of non-neoplastic tissues, we demonstrated that HL LN-derived mesenchymal stromal cells and HL cells increased the Young's modulus of the extracellular microenvironment through the expression of LOX. Indeed, LOX inhibition by β-aminopropionitrile prevented the gelatin stiffness increase.

CONCLUSIONS

These data indicate that different mechanical, topographical and/or architectural modifications of ECM are detectable in human lymphomas and are related to their histotype and grading.