Heart failure (HF) is a frequent consequence of myocardial infarction (MI). Identification of the precise, time-dependent composition of inflammatory cells may provide clues for the establishment of new biomarkers and therapeutic approaches targeting post-MI HF. Here, we investigate the spatiotemporal dynamics of MI-associated immune cells in a mouse model of MI using spatial transcriptomics and single-cell RNA-sequencing (scRNA-seq). We identify twelve major immune cell populations; their proportions dynamically change after MI. Macrophages are the most abundant population at all-time points (>60%), except for day 1 post-MI. Trajectory inference analysis shows upregulation of Trem2 expression in macrophages during the late phase post-MI. In vivo injection of soluble Trem2 leads to significant functional and structural improvements in infarcted hearts. Our data contribute to a better understanding of MI-driven immune responses and further investigation to determine the regulatory factors of the Trem2 signaling pathway will aid the development of novel therapeutic strategies for post-MI HF.

Background: Since hepatocellular carcinoma (HCC) is one of the leading causes of cancer death worldwide, it is still important to understand hepatocarcinogenesis mechanisms and identify effective markers for tumor progression to improve prognosis. Amplification and overexpression of Tropomyosin3 (TPM3) are frequently observed in HCC, but its biological meanings have not been properly defined. In this study, we aimed to elucidate the roles of TPM3 and related molecular mechanisms. Methods: TPM3-siRNA was transfected into 2 HCC cell lines, HepG2 and SNU-475, which had shown overexpression of TPM3. Knockdown of TPM3 was verified by real-time qRT-PCR and western blotting targeting TPM3. Migration and invasion potentials were examined using transwell membrane assays. Cell growth capacity was examined by colony formation and soft agar assays. Results: Silencing TPM3 resulted in significant suppression of migration and invasion capacities in both HCC cell lines. To elucidate the mechanisms behind suppressed migration and invasiveness, we examined expression levels of Snail and E-cadherin known to be related to epithelial-mesenchymal transition (EMT) after TPM3 knockdown. In the TPM3 knockdown cells, E-cadherin expression was significantly upregulated and Snail downregulated compared with negative control. TPM3 knockdown also inhibited colony formation and anchorage independent growth of HCC cells. Conclusions: Based on our findings, we formulate a hypothesis that overexpression of TPM3 activates Snail mediated EMT, which will repress E-cadherin expression and that it confers migration or invasion potentials to HCC cells during hepatocarcinogenesis. To our knowledge, this is the first evidence that TPM3 gets involved in migration and invasion of HCCs by modifying EMT pathway.

Background: Although most differentiated thyroid carcinomas (DTCs) have indolent behavior, DTCs with distant metastasis have a poor prognosis. However, there are no validated markers that predict the risk of distant metastasis and the prognosis of DTC. We aimed to develop a genetic classifier for predicting the outcomes of DTC patients with distant metastases. Methods: Targeted deep sequencing of 157 cancer-related genes was performed for 61 DTCs with distant metastases. A candidate mutation was validated with independent thyroid cancer samples using digital polymerase chain reaction. Results: The most frequently mutated gene in the 61 DTCs was BRAF ( n = 31, 51%), followed by TERT promoter ( n = 28, 46%), NRAS ( n = 13, 11%), PLEKHS1 promoter ( n = 6, 10%), and STK11 ( n = 6, 10%) mutations. PLEKHS1 promoter mutations were more common in the radioactive iodine (RAI)-refractory cases ( p = 0.003). Losses of 9q and 11q were associated with RAI-refractory disease ( p = 0.002) and cancer-specific mortality ( p = 0.028), respectively. In multivariate analysis, bone metastasis (adjusted odds ratio [aOR] = 15.17, 95% confidence interval [CI 3.38–68.06], p < 0.001) and at least one mutation in the TERT promoter, the PLEKHS1 promoter, or TP53 (aOR = 7.64 [CI 1.78–32.76], p = 0.006) remained significant factors associated with RAI-refractoriness. In independently collected papillary thyroid carcinomas without initial distant metastasis ( n = 75), a PLEKHS1 promoter mutation was only found in one case that developed distant metastasis during the follow-up period. We developed a genetic classifier consisting of BRAF , RAS , the TERT promoter, the PLEKHS1 promoter, and TP53 for categorizing the prognosis of patients with DTC with distant metastasis. In the poor-prognosis group, 61% of the patients were RAI-refractory and death occurred in 21% during the follow-up. In the intermediate-prognosis group, 29% were RAI-refractory, but no death occurred. In the good-prognosis group, all patients were RAI-responsive and no death occurred. Conclusions: Mutations in the PLEKHS1 promoter are a novel genetic marker of aggressive DTC. Our genetic classifier can be useful for predicting RAI-refractory disease and poor prognosis in DTC patients with distant metastases.

Background: The full extent of chromosomal alterations and their biological implications in early breast carcinogenesis has not been well examined. In this study, we aimed to identify chromosomal alterations associated with poor prognosis in early-stage breast cancers (EBC). Methods: A total of 145 EBCs (stage I and II) were examined in this study. We analyzed copy number alterations in a discovery set of 48 EBCs using oligoarray-comparative genomic hybridization. In addition, the recurrently altered regions (RARs) associated with poor prognosis were validated using an independent set of 97 EBCs. Results: A total of 23 RARs were defined in the discovery set. Six were commonly detected in both stage I and II groups (> 50%), suggesting their connection with early breast tumorigenesis. There were gains on 1q21.2-q21.3, 8q24.13, 8q24.13-21, 8q24.3, and 8q24.3 and a loss on 8p23.1-p22. Among the 23 RARs, copy number gains on 16p11.2 (NUPR1) and 17q12 (ERBB2) showed a significant association with poor survival (P = 0.0186 and P = 0.0186, respectively). The patients simultaneously positive for both gains had a significantly worse prognosis (P = 0.0001). In the independent replication, the patients who were double-positive for NUPR1-ERBB2 gains also had a significantly poorer prognosis on multivariate analysis (HR = 7.31, 95% CI 2.65-20.15, P = 0.0001). Conclusions: The simultaneous gain of NUPR1 and ERBB2 can be a significant predictor of poor prognosis in EBC. Our study will help to elucidate the molecular mechanisms underlying early-stage breast cancer tumorigenesis. This study also highlights the potential for using combinations of copy number alterations as prognosis predictors for EBC.

Both the tumor and tumor microenvironment (TME) are crucial for pathogenesis and chemotherapy resistance in multiple myeloma (MM). Bortezomib, commonly used for MM treatment, works on both MM and TME cells, but innate and acquired resistance easily develop. By single-cell RNA sequencing (scRNA-seq), we investigated bone marrow aspirates of 18 treatment-naïve MM patients who later received bortezomib-based treatments. Twelve plasma and TME cell types and their subsets were identified. Suboptimal responders (SORs) to bortezomib exhibited higher copy number alteration burdens than optimal responders (ORs). Forty-four differentially expressed genes for SORs based on scRNA-seq data were further analyzed in an independent cohort of 90 treatment-naïve MMs, where 24 genes were validated. A combined model of three clinical variables (older age, low absolute lymphocyte count, and no autologous stem cell transplantation) and 24 genes was associated with bortezomib responsiveness and poor prognosis. In T cells, cytotoxic memory, proliferating, and dysfunctional subsets were significantly enriched in SORs. Moreover, we identified three monocyte subsets associated with bortezomib responsiveness and an MM-specific NK cell trajectory that ended with an MM-specific subset. scRNA-seq predicted the interaction of the GAS6-MERTK, ALCAM-CD6, and BAG6-NCR gene networks. Of note, tumor cells from ORs and SORs were the most prominent sources of ALCAM on effector T cells and BAG6 on NK cells, respectively. Our results indicate that the complicated compositional and molecular changes of both tumor and immune cells in the bone marrow (BM) milieu are important in the development and acquisition of resistance to bortezomib-based treatment of MM.