Acral melanoma (AM) is a rare subtype of melanoma characterized by a high incidence of lymph node (LN) metastasis, a critical factor in tumor dissemination and therapeutic decision-making. Here, we employ single-cell and spatial transcriptomic analyses to investigate the dynamic evolution of early AM dissemination. Our findings reveal substantial inter- and intra-tumor heterogeneity in AM, alongside a highly immunosuppressive tumor microenvironment and complex intercellular communication networks, particularly in patients with LN metastasis. Notably, we identify a strong association between MYC⁺ Melanoma (MYC⁺MEL) and FGFBP2⁺NKT cells with LN metastasis. Furthermore, we demonstrate that LN metastasis requires a metabolic shift towards fatty acid oxidation (FAO) induced by MITF in MYC⁺MEL cells. Etomoxir, a clinically approved FAO inhibitor, can effectively suppress MITF-mediated LN metastasis. This comprehensive dataset enhances our understanding of LN metastasis in AM, and provides insights into the potential therapeutic targeting for the management of early AM dissemination.

Background: Layilin (LAYN) represents a valuable prognostic biomarker across various tumor types, while also serving as an innovative indicator of dysfunctional or exhausted CD8⁺ T cells and exhibiting correlation with immune context. However, the immune function and prognostic significance of LAYN in hepatocellular carcinoma (HCC) remain unexplored. Therefore, our objective is to investigate the role of LAYN in CD8⁺ T cell exhaustion, clinical prognosis, and the tumor microenvironment within HCC. Methods: TIMER or GEPIA databases were used to analyze LAYN expression level and its correlation with immune infiltration in HCC. Bioinformatics analysis was conducted on TCGA and scRNA-seq cohorts. The evaluation of LAYN expression level in fresh specimens was performed through IF, IHC, and ELISA assays. Flow cytometry and mRNA-seq were employed to investigate co-expressed genes of LAYN, the LAYN⁺CD8⁺ T cell exhaustion signature and immune function. Cell proliferation ability and killing activity were assessed using CCK8 and CFSE/PI. Results: The expression level of LAYN in HCC tumors was significantly higher compared to peri-tumors. Patients with high levels of LAYN exhibited poorer OS. GO or KEGG analysis confirmed that LAYN was involved in immune response and was positively associated with CD8⁺ T cell immune infiltration levels. Furthermore, LAYN negatively regulated the immune function of CD8⁺ T cells, leading to dysfunctional phenotypes characterized by elevated levels of CD39, TIM3 and reduced levels of perforin, TNF-α, Ki-67. CFSE/PI assays demonstrated that LAYN⁺CD8⁺ T cells displayed decreased cytotoxic activity. Additionally, there was a positive correlation between LAYN and CD146 levels, which are involved in adhesion and localization processes of CD8⁺ T cells. Interestingly, blocking LAYN partially restored the exhaustion properties of CD8⁺ T cells. Conclusion: LAYN exhibits a strong correlation with immune infiltration in the TME and represents a novel biomarker for predicting clinical prognosis in HCC. Moreover, targeting LAYN may hold promise as an effective strategy for HCC immunotherapy.

Cardiac fibrosis is one of the common pathological processes in many cardiovascular diseases characterized by excessive extracellular matrix deposition. SerpinE2 is a kind of protein that inhibits peptidase in extracellular matrix and up-regulated tremendously in mouse model of cardiac fibrosis induced by pressure-overloaded via transverse aortic constriction (TAC) surgery. However, its effect on cardiac fibroblasts (CFs), collagen secretion and the underlying mechanism remains unclear. In this study, DyLight® 488 green fluorescent dye or His-tagged proteins were used to label the exogenous serpinE2 protein. It was showed that extracellular serpinE2 translocated into CFs by low-density lipoprotein receptor-related protein 1 (LRP1) and urokinase plasminogen activator receptor (uPAR) of cell membrane through endocytosis. Knockdown of LRP1 or uPAR reduced the level of serpinE2 in CFs and down-regulated the collagen expression. Inhibition of the endocytosis of serpinE2 could inhibit ERK1/2 and β-catenin signaling pathways and subsequently attenuated collagen secretion. Knockdown of serpinE2 attenuates cardiac fibrosis in TAC mouse. We conclude that serpinE2 could be translocated into cardiac fibroblasts due to endocytosis through directly interact with the membrane protein LRP1 and uPAR, and this process activated the ERK1/2, β-catenin signaling pathways, consequently promoting collagen production.

Imatinib mesylate (IM) has dramatically improved the outcomes of gastrointestinal stromal tumor (GIST) patients. However, the clinical responses of IM may considerably vary among single individuals. This study aimed to investigate the influences of genetic polymorphisms of drug-metabolizing enzyme (CYP3A4), transporters (ABCB1, ABCG2), and nuclear receptor (Pregnane X Receptor (PXR, encoded by NR1I2)) on IM plasma levels and related adverse reactions in Chinese GIST patients. A total of 68 Chinese GIST patients who have received IM 300–600 mg/day were genotyped for six single nucleotide polymorphisms (SNPs) (CYP3A4 rs2242480; ABCB1 rs1045642; ABCG2 rs2231137; NRI12 rs3814055, rs6785049, rs2276706), and the steady-state IM trough plasma concentrations were measured by a validated HPLC method. There were statistically significant variances in the steady-state IM trough plasma concentrations (from 272.22 to 4365.96 ng/mL). Subjects of GG in rs2242480, T allele carriers in rs1045642 and CC in rs3814055 had significantly higher steady-state IM dose-adjusted trough plasma concentrations. Subjects of CC in rs3814055 had significantly higher incidence rate of edema. The genetic polymorphisms of rs2242480, rs1045642, rs3814055 were significantly associated with IM plasma levels, and the genetic variations of rs3814055 were significantly associated with the incidence rate of edema in Chinese GIST patients. The current results may serve as valuable fundamental knowledge for IM therapy in Chinese GIST patients.

Known as solid tumors of intermediate malignant potential, most inflammatory myofibroblastic tumors (IMTs) are treatable as long as the tumor is en-bloc resected. However, in some cases, the tumors have recurred and grown rapidly after successful surgery. Some of these tumors were classified as an epithelioid inflammatory myofibroblastic sarcoma (EIMS). Most previously reported EIMSs have been caused by RANBP2-ALK fusion gene. We herein report an EIMS case caused by an EML4-ALK fusion gene. RNAseq was conducted to find out the new ALK fusion gene which could not be detected following previously reported RT-PCR methods for EIMS cases with RANBP2-ALK fusion gene. After that, RT-PCR was also conducted to further prove the newly found fusion gene. Immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) test were applied to find out the unique morphological characters compared with the previous reported EIMS cases. We found an EIMS case who was suffering from a rapid recurrence after cytoreducyive surgery was done to relieve the exacerbating symptoms. The patient finally died for tumor lysis syndrome after the application of crizotinib. Distinctive ALK staining under the membrane and relatively weak ALK staining in the cytoplasm could also be observed. RNAseq and RT-PCR further revealed that the tumor harbored an EML4-ALK fusion gene. In conclusion, this is the first EIMS demonstrated to have been caused by the formation of an EML4-ALK fusion gene. This enriches the spectrum of EIMS and enlarges the horizon for the study of EIMS. The experience we shared in managing this kind of disease by discussing aspects of its success and failure could be of great value for surgeons and pathologists.