PAX6 promotes neuroendocrine phenotypes of prostate cancer via enhancing MET/STAT5A-mediated chromatin accessibility

BACKGROUND

Neuroendocrine prostate cancer (NEPC) is a lethal subset of prostate cancer which is characterized by neuroendocrine differentiation and loss of androgen receptor (AR) signaling. Growing evidence reveals that cell lineage plasticity is crucial in the failure of NEPC therapies. Although studies suggest the involvement of the neural transcription factor PAX6 in drug resistance, its specific role in NEPC remains unclear.

METHODS

The expression of PAX6 in NEPC was identified via bioinformatics and immunohistochemistry. CCK8 assay, colony formation assay, tumorsphere formation assay and apoptosis assay were used to illustrate the key role of PAX6 in the progression of in vitro. ChIP and Dual-luciferase reporter assays were conducted to confirm the binding sequences of AR in the promoter region of PAX6, as well as the binding sequences of PAX6 in the promoter regions of STAT5A and MET. For in vivo validation, the xenograft model representing NEPC subtype underwent pathological analysis to verify the significant role of PAX6 in disease progression. Complementary diagnoses were established through public clinical datasets and transcriptome sequencing of specific cell lines. ATAC-seq was used to detect the chromatin accessibility of specific cell lines.

RESULTS

PAX6 expression was significantly elevated in NEPC and negatively regulated by AR signaling. Activation of PAX6 in non-NEPC cells led to NE trans-differentiation, while knock-down of PAX6 in NEPC cells inhibited the development and progression of NEPC. Importantly, loss of AR resulted in an enhanced expression of PAX6, which reprogramed the lineage plasticity of prostate cancer cells to develop NE phenotypes through the MET/STAT5A signaling pathway. Through ATAC-seq, we found that a high expression level of PAX6 elicited enhanced chromatin accessibility, mainly through attenuation of H4K20me3, which typically causes chromatin silence in cancer cells.

CONCLUSION

This study reveals a novel neural transcription factor PAX6 could drive NEPC progression and suggest that it might serve as a potential therapeutic target for the management of NEPC.

Zeb1-controlled metabolic plasticity enables remodeling of chromatin accessibility in the development of neuroendocrine prostate cancer

Cell plasticity has been found to play a critical role in tumor progression and therapy resistance. However, our understanding of the characteristics and markers of plastic cellular states during cancer cell lineage transition remains limited. In this study, multi-omics analyses show that prostate cancer cells undergo an intermediate state marked by Zeb1 expression with epithelial-mesenchymal transition (EMT), stemness, and neuroendocrine features during the development of neuroendocrine prostate cancer (NEPC). Organoid-formation assays and in vivo lineage tracing experiments demonstrate that Zeb1+ epithelioid cells are putative cells of origin for NEPC. Mechanistically, Zeb1 transcriptionally regulates the expression of several key glycolytic enzymes, thereby predisposing tumor cells to utilize glycolysis for energy metabolism. During this process, lactate accumulation-mediated histone lactylation enhances chromatin accessibility and cellular plasticity including induction of neuro-gene expression, which promotes NEPC development. Collectively, Zeb1-driven metabolic rewiring enables the epigenetic reprogramming of prostate cancer cells to license the adeno-to-neuroendocrine lineage transition.

Uncovering impaired mitochondrial and lysosomal function in adipose-derived stem cells from obese individuals with altered biological activity

BACKGROUND

Adipose-derived stem cells (ADSCs) have been extensively used in preclinical and clinical trials for treating various diseases. However, the differences between ADSCs from lean individuals (L-ADSCs) and those from obese individuals (O-ADSCs) have not been thoroughly investigated, particularly regarding their mitochondrial and lysosomal functions. Therefore, this study aims to evaluate the differences between L-ADSCs and O-ADSCs in terms of cell biological activity, mitochondria, and lysosomes.

METHODS

We first isolated and cultured L-ADSCs and O-ADSCs. We then compared the differences between the two groups in terms of biological activity, including cell proliferation, differentiation potential, and their effect on the polarization of macrophages. Additionally, we observed the mitochondrial and lysosomal morphology of ADSCs using an electronic microscope, MitoTracker Red, and lysotracker Red dyes. We assessed mitochondrial function by examining mitochondrial membrane potential and membrane fluidity, antioxidative ability, and cell energy metabolism. Lysosomal function was evaluated by measuring autophagy and phagocytosis. Finally, we performed transcriptome analysis of the ADSCs using RNA sequencing.

RESULTS

The biological activities of O-ADSCs were decreased, including cell immunophenotypic profiles, cell proliferation, and differentiation potential. Furthermore, compared to L-ADSCs, O-ADSCs promoted M1-type macrophage polarization and inhibited M2-type macrophage polarization. Additionally, the mitochondrial morphology of O-ADSCs was altered, with the size of the cells becoming smaller and mitochondrial fragments increasing. O-ADSCs also exhibited decreased mitochondrial membrane potential and membrane fluidity, antioxidative ability, and energy metabolism. With respect to lysosomes, O-ADSCs contained ungraded materials in their lysosomes, enhanced lysosomal permeability, and reduced autophagy and phagocytosis ability. RNA sequence analysis indicated that the signalling pathways related to cell senescence, cancer, and inflammation were upregulated, whereas the signalling pathways associated with stemness, cell differentiation, metabolism, and response to stress and stimuli were downregulated.

CONCLUSIONS

This study indicates that ADSCs from individuals (BMI > 30 kg/m2) exhibit impaired mitochondrial and lysosomal function with decreased biological activity.

Comparative evaluation of antitumor effects of TNF superfamily costimulatory ligands delivered by mesenchymal stem cells

Stimulation of costimulatory receptors serves as an alternative immunotherapeutic strategy other than checkpoint inhibition. However, systemic administration of the agonistic antibodies is associated with severe toxicities, which is one of the major obstacles for their clinical application. This study aimed to develop a mesenchymal stem cell (MSC)-based system for tumor-targeted delivery of TNF superfamily ligands and assess their potential in enhancing antitumor immunity. Here we established an MSC-based system for tumor-targeted delivery of TNF superfamily ligands, including TNFSF4, 9 and 18. The TNFSF receptors (TNFRSFs) were evaluated in mouse models and patient samples for lung and colorectal cancers. TNFRSFs were all expressed at various levels on tumor-infiltrated lymphocytes, with TNFRSF18 being the most prevalent receptor. Human umbilical cord-derived MSCs expressing these costimulatory ligands (MSC-TNFSFs) effectively activated lymphocytes in vitro and elicited antitumor immunity in mice. TNFSF4 showed the least antitumor efficacy in both LLC1 and CT26 tumor models. MSC-TNFSF9 showed the most potent tumor-inhibiting effect in the LLC1 tumor model, while MSCs expressing TNFSF18 in combination with CXCL9 most significantly repressed CT26 tumor growth. Overall, TNFSF9 and TNFSF18 exhibited stronger lymphocyte-stimulating and antitumor activities than TNFSF4. Our study provides evidence that antitumor effects of agonism of different costimulatory receptors may vary in different tumor types and presents a promising approach for targeted delivery of TNF superfamily costimulatory ligands to avoid the systemic toxicities and side effects associated with immune agonist antibodies.

ADORA2A-driven proline synthesis triggers epigenetic reprogramming in neuroendocrine prostate and lung cancers

Cell lineage plasticity is one of the major causes for the failure of targeted therapies in various cancers. However, the driver and actionable drug targets in promoting cancer cell lineage plasticity are scarcely identified. Here, we found that a G protein-coupled receptor, ADORA2A, is specifically upregulated during neuroendocrine differentiation, a common form of lineage plasticity in prostate cancer and lung cancer following targeted therapies. Activation of the ADORA2A signaling rewires the proline metabolism via an ERK/MYC/PYCR cascade. Increased proline synthesis promotes deacetylases SIRT6/7-mediated deacetylation of histone H3 at lysine 27 (H3K27), and thereby biases a global transcriptional output toward a neuroendocrine lineage profile. Ablation of Adora2a in genetically engineered mouse models inhibits the development and progression of neuroendocrine prostate and lung cancers, and, intriguingly, prevents the adenocarcinoma-to-neuroendocrine phenotypic transition. Importantly, pharmacological blockade of ADORA2A profoundly represses neuroendocrine prostate and lung cancer growth in vivo. Therefore, we believe that ADORA2A can be used as a promising therapeutic target to govern the epigenetic reprogramming in neuroendocrine malignancies.

hnRNPA2B1 promotes the occurrence and progression of hepatocellular carcinoma by downregulating PCK1 mRNA via a m6A RNA methylation manner

BACKGROUND

N6-methyladenosine (m6A) is the most prevalent RNA modification. Although hnRNPA2B1, as a reader of m6A modification, has been reported to promote tumorigenesis in a few types of tumors, its role in hepatocellular carcinoma (HCC) and the underlying molecular mechanism remains unclear.

METHODS

Multiple public databases were used to analyze the expression of hnRNPA2B1 in HCC and its correlation with survival prognosis. We employed a CRISPR-Cas9 sgRNA editing strategy to knockout hnRNPA2B1 expression in HCC cells. The biological function of hnRNPA2B1 in vitro in HCC cells was measured by CCK8, colony formation, migration, and invasion assay. The tumorigenic function of hnRNPA2B1 in vivo was determined by a subcutaneous tumor formation experiment and a HCC mouse model via tail injection of several plasmids into the mouse within 5s-7s. RNA binding protein immunoprecipitation (RIP) experiment using hnRNPA2B1 was performed to test the target genes of hnRNPA2B1 and methylated RNA immunoprecipitation (MeRIP) assay was performed to explore the m6A methylated mRNA of target genes.

RESULTS

hnRNPA2B1 highly expressed in HCC tissues, correlated with high grades and poor prognosis. Its knockout reduced HCC cell proliferation, migration, and invasion in vitro, while overexpression promoted these processes. hnRNPA2B1-knockout cells inhibited tumor formation in graft experiments. In HCC mice, endogenous knockout attenuated hepatocarcinogenesis. RNA-seq showed downregulated gluconeogenesis with high hnRNPA2B1 expression. hnRNPA2B1 negatively correlated with PCK1, a key enzyme. RIP assay revealed hnRNPA2B1 binding to PCK1 mRNA. hnRNPA2B1 knockout increased m6A-methylation of PCK1 mRNA. Interestingly, PCK1 knockout partially counteracted tumor inhibition by hnRNPA2B1 knockout in mice.

CONCLUSION

Our study indicated that hnRNPA2B1 is highly expressed in HCC and correlated with a poor prognosis. hnRNPA2B1 promotes the tumorigenesis and progression of HCC both in vitro and in vivo. Moreover, hnRNPA2B1 downregulates the expression of PCK1 mRNA via a m6A methylation manner. More importantly, the ability of hnRNPA2B1 to induce tumorigenesis and progression in HCC is dependent on its ability to decrease the expression of PCK1. Therefore, this study suggested that hnRNPA2B1 might be a diagnostic marker of poor prognosis of HCC and a potential therapeutic target for HCC patients.

Setd2 deficiency promotes gastric tumorigenesis through inhibiting the SIRT1/FOXO pathway

Gastric cancer (GC) is the fifth most common cancer and the second leading cause of cancer death globally. SETD2 is a histone methyltransferase catalyzing tri-methylation of H3K36 (H3K36me3) and has been shown to participate in diverse biological processes and human tumors. However, the mechanism of SETD2 in GC remains unclear. Here, we reported that Setd2 deficiency predicts poor prognosis of gastric cancer. SETD2 loss facilitated H. felis/MNU and c-Myc-induced gastric tumorigenesis, respectively. The mouse model of stomach-specific Setd2 depletion together with c-MYC overexpression (AMS) developed high-grade epithelial defects, intestinal metaplasia and dysplasia at only 10-12 weeks of age. Mechanistically, Setd2 depletion resulted in impaired epigenetic regulation of Sirt1, thus inhibiting the SIRT1/FOXO pathway. Moreover, the agonists of FOXO signaling or overexpression of SIRT1 significantly rescued the enhanced cell proliferation and migration caused by Setd2 deficiency in SGC7901 cells. Together, our findings highlight an epigenetic mechanism by which SETD2 regulates gastric tumorigenesis through SIRT1/FOXO pathway. It may also pave the way for the development of targeted, patient-tailored therapies for GC patients with Setd2 deficiency.

SETD2 deficiency accelerates sphingomyelin accumulation and promotes the development of renal cancer

Patients with polycystic kidney disease (PKD) encounter a high risk of clear cell renal cell carcinoma (ccRCC), a malignant tumor with dysregulated lipid metabolism. SET domain-containing 2 (SETD2) has been identified as an important tumor suppressor and an immunosuppressor in ccRCC. However, the role of SETD2 in ccRCC generation in PKD remains largely unexplored. Herein, we perform metabolomics, lipidomics, transcriptomics and proteomics within SETD2 loss induced PKD-ccRCC transition mouse model. Our analyses show that SETD2 loss causes extensive metabolic reprogramming events that eventually results in enhanced sphingomyelin biosynthesis and tumorigenesis. Clinical ccRCC patient specimens further confirm the abnormal metabolic reprogramming and sphingomyelin accumulation. Tumor symptom caused by Setd2 knockout is relieved by myriocin, a selective inhibitor of serine-palmitoyl-transferase and sphingomyelin biosynthesis. Our results reveal that SETD2 deficiency promotes large-scale metabolic reprogramming and sphingomyelin biosynthesis during PKD-ccRCC transition. This study introduces high-quality multi-omics resources and uncovers a regulatory mechanism of SETD2 on lipid metabolism during tumorigenesis.

Low-dose metronomic chemotherapy triggers oxidized mtDNA sensing inside tumor cells to potentiate CD8+T anti-tumor immunity

Low-dose metronomic (LDM) chemotherapy, the frequent and continuous use of low doses of conventional chemotherapeutics, is emerging as a promising form of chemotherapy utilization. LDM chemotherapy exerts immunomodulatory effects. However, the underlying mechanism is not fully understood. Here we found that suppressing tumor growth by LDM chemotherapy was dependent on the activation of CD8+T cells. LDM chemotherapy potentiated the cytotoxic function of CD8+T cells by stimulating cancer-cell autonomous type I interferon (IFN) induction. Mechanistically, LDM chemotherapy evoked mitochondrial dysfunction and increased reactive oxygen species (ROS) production. ROS triggered the oxidation of cytosolic mtDNA, which was sensed by cGAS-STING, consequently inducing type I IFN production in the cancer cells. Moreover, the cGAS-STING-IFN axis increased PD-L1 expression and predicted favorable clinical responses to chemoimmunotherapy. Antioxidant N-acetylcysteine inhibited oxidized mtDNA-induced type I IFN production and attenuated the efficacy of combination therapy with LDM chemotherapy and PD-L1 blockade. This study elucidates the critical role of intratumoral oxidized mtDNA sensing in LDM chemotherapy-mediated activation of CD8+T cell immune response. These findings may provide new insights for designing combinatorial immunotherapy for cancer patients.

An Early Neoplasia Index (ENI10), Based on Molecular Identity of CD10 Cells and Associated Stemness Biomarkers, is a Predictor of Patient Outcome in Many Cancers

An accurate estimate of patient survival at diagnosis is critical to plan efficient therapeutic options. A simple and multiapplication tool is needed to move forward the precision medicine era. Taking advantage of the broad and high CD10 expression in stem and cancers cells, we evaluated the molecular identity of aggressive cancer cells. We used epithelial primary cells and developed a breast cancer stem cell–based progressive model. The superiority of the early-transformed isolated molecular index was evaluated by large-scale analysis in solid cancers. BMP2-driven cell transformation increases CD10 expression which preserves stemness properties. Our model identified a unique set of 159 genes enriched in G2–M cell-cycle phases and spindle assembly complex. Using samples predisposed to transformation, we confirmed the value of an early neoplasia index associated to CD10 (ENI10) to discriminate premalignant status of a human tissue. Using a stratified Cox model, a large-scale analysis (>10,000 samples, The Cancer Genome Atlas Pan-Cancer) validated a strong risk gradient (HRs reaching HR = 5.15; 95% confidence interval: 4.00–6.64) for high ENI10 levels. Through different databases, Cox regression model analyses highlighted an association between ENI10 and poor progression-free intervals for more than 50% of cancer subtypes tested, and the potential of ENI10 to predict drug efficacy. The ENI10 index constitutes a robust tool to detect pretransformed tissues and identify high-risk patients at diagnosis. Owing to its biological link with refractory cancer stem cells, the ENI10 index constitutes a unique way of identifying effective treatments to improve clinical care.

SIGNIFICANCE

We identified a molecular signature called ENI10 which, owing to its biological link with stem cell properties, predicts patient outcome and drugs efficiency in breast and several other cancers. ENI10 should allow early and optimized clinical management of a broad number of cancers, regardless of the stage of tumor progression.

Histone methyltransferase KMT5C drives liver cancer progression and directs therapeutic response to PARP inhibitors

BACKGROUND AND AIMS

Epigenetic plasticity is a major challenge in cancer-targeted therapy. However, the molecular basis governing this process has not yet been clearly defined. Despite the considerable success of poly(ADP-ribose) polymerase inhibitors (PARPi) in cancer therapy, the limited response to PARPi, especially in HCC, has been a bottleneck in its clinical implications. Herein, we investigated the molecular basis of the histone methyltransferase KMT5C (lysine methyltransferase 5C) that governs PARPi sensitivity and explored a potential therapeutic strategy for enhancing PARPi efficacy.

APPROACH AND RESULTS

We identified KMT5C, a trimethyltransferase of H4K20, as a targetable epigenetic factor that promoted liver tumor growth in mouse de novo MYC/Trp53-/- and xenograft liver tumor models. Notably, induction of KMT5C by environmental stress was crucial for DNA repair and HCC cell survival. Mechanistically, KMT5C interacted with the pivotal component of homologous recombination repair, RAD51, and promoted RAD51/RAD54 complex formation, which was essential for the activation of dsDNA breaks repair. This effect depended on the methyltransferase activity of KMT5C. We further demonstrated that the function of KMT5C in promoting HCC progression was dependent on RAD51. Importantly, either a pharmacological inhibitor (A196) or genetic inhibition of KMT5C sensitized liver cancer cells to PARPi.

CONCLUSIONS

KMT5C played a vital role in promoting liver cancer progression by activating the DNA repair response. Our results revealed a novel therapeutic approach using the KMT5C inhibitor A196, concurrent with olaparib, as a potential HCC therapy.

IL-1β Is an Androgen-Responsive Target in Macrophages for Immunotherapy of Prostate Cancer

Great attention is paid to the role of androgen receptor (AR) as a central transcriptional factor in driving the growth of prostate cancer (PCa) epithelial cells. However, the understanding of the role of androgen in PCa-infiltrated immune cells and the impact of androgen deprivation therapy (ADT), the first-line treatment for advanced PCa, on the PCa immune microenvironment remains limited. On the other hand, immune checkpoint blockade has revolutionized the treatment of certain cancer types, but fails to achieve any benefit in advanced PCa, due to an immune suppressive environment. In this study, it is reported that AR signaling pathway is evidently activated in tumor-associated macrophages (TAMs) of PCa both in mice and humans. AR acts as a transcriptional repressor for IL1B in TAMs. ADT releases the restraint of AR on IL1B and therefore leads to an excessive expression and secretion of IL-1β in TAMs. IL-1β induces myeloid-derived suppressor cells (MDSCs) accumulation that inhibits the activation of cytotoxic T cells, leading to the immune suppressive microenvironment. Critically, anti-IL-1β antibody coupled with ADT and the immune checkpoint inhibitor anti-PD-1 antibody exerts a stronger anticancer effect on PCa following castration. Together, IL-1β is an important androgen-responsive immunotherapeutic target for advanced PCa.

Numb/Parkin-directed mitochondrial fitness governs cancer cell fate via metabolic regulation of histone lactylation

Cell plasticity and neuroendocrine differentiation in prostate and lung adenocarcinomas are one of the major reasons for therapeutic resistance to targeted therapy. Whether and how metabolic changes contribute to this adenocarcinoma-to-neuroendocrine cell fate transition remains largely unclear. Here we show that neuroendocrine prostate or lung cancer cells possess mostly fragmented mitochondria with low membrane potential and rely on glycolysis for energy metabolism. We further show an important role of the cell fate determinant Numb in mitochondrial quality control via binding to Parkin and facilitating Parkin-mediated mitophagy. Deficiency in the Numb/Parkin pathway in prostate or lung adenocarcinomas causes a metabolic reprogramming featured with a significant increase in production of lactate acid, which subsequently leads to an upregulation of histone lactylation and transcription of neuroendocrine-associated genes. Collectively, the Numb/Parkin-directed mitochondrial fitness is a key metabolic switch and a promising therapeutic target on cancer cell plasticity through the regulation of histone lactylation.

TRIM59 is suppressed by androgen receptor and acts to promote lineage plasticity and treatment-induced neuroendocrine differentiation in prostate cancer

The incidence of treatment-induced neuroendocrine prostate cancer (t-NEPC) has been greatly increasing after the usage of secondgeneration androgen receptor (AR) pathway inhibitors (ARPIs). Neuroendocrine differentiation (NED) is closely associated with ARPI treatment failure and poor prognosis in prostate cancer (PCa) patients. However, the molecular mechanisms of NED are not fully understood. Here we report that upregulation of TRIM59, a TRIM family protein, is strongly correlated with ARPI treatment mediated NED and shorter patient survival in PCas. AR binds to TRIM59 promoter and represses its transcription. ARPI treatment leads to a reversal of repressive epigenetic modifications on TRIM59 gene and the transcriptional restraint on TRIM59 by AR. Upregulated TRIM59 then drives the NED of PCa by enhancing the degradation of RB1 and P53 and upregulating downstream lineage plasticity-promoting transcription factor SOX2. Altogether, TRIM59 is negatively regulated by AR and acts as a key driver for NED in PCas. Our study provides a novel prognostic marker for PCas and shed new light on the molecular pathogenesis of t-NEPC, a deadly variant of PCa.

AMPK induces degradation of the transcriptional repressor PROX1 impairing branched amino acid metabolism and tumourigenesis

Tumour cell metabolic plasticity is essential for tumour progression and therapeutic responses, yet the underlying mechanisms remain poorly understood. Here, we identify Prospero-related homeobox 1 (PROX1) as a crucial factor for tumour metabolic plasticity. Notably, PROX1 is reduced by glucose starvation or AMP-activated protein kinase (AMPK) activation and is elevated in liver kinase B1 (LKB1)-deficient tumours. Furthermore, the Ser79 phosphorylation of PROX1 by AMPK enhances the recruitment of CUL4-DDB1 ubiquitin ligase to promote PROX1 degradation. Downregulation of PROX1 activates branched-chain amino acids (BCAA) degradation through mediating epigenetic modifications and inhibits mammalian target-of-rapamycin (mTOR) signalling. Importantly, PROX1 deficiency or Ser79 phosphorylation in liver tumour shows therapeutic resistance to metformin. Clinically, the AMPK-PROX1 axis in human cancers is important for patient clinical outcomes. Collectively, our results demonstrate that deficiency of the LKB1-AMPK axis in cancers reactivates PROX1 to sustain intracellular BCAA pools, resulting in enhanced mTOR signalling, and facilitating tumourigenesis and aggressiveness.

Biological activity reduction and mitochondrial and lysosomal dysfunction of mesenchymal stem cells aging in vitro

BACKGROUND

Mesenchymal stem cells (MSCs) have been extensively used for the treatment of various diseases in preclinical and clinical trials. In vitro propagation is needed to attain enough cells for clinical use. However, cell aging and viability reduction caused by long-time culture have not been thoroughly investigated, especially for the function of mitochondria and lysosomes. Therefore, this study was designed to detect mitochondrial and lysosomal activity, morphological and functional changes in human umbilical cord MSCs (UMSCs) after long-time culture.

METHODS

First, we examined cell activities, including proliferation and immigration ability, differentiation potential, and immunosuppressive capacity of UMSCs at an early and late passages as P4 (named UMSC-P4) and P9 (named UMSC-P9), respectively. Then, we compared the mitochondrial morphology of UMSC-P4 and UMSC-P9 using the electronic microscope and MitoTracker Red dyes. Furthermore, we investigated mitochondrial function, including mitochondrial membrane potential, antioxidative ability, apoptosis, and ferroptosis detected by respective probe. Cell energy metabolism was tested by mass spectrometry. In addition, we compared the lysosomal morphology of UMSC-P4 and UMSC-P9 by electronic microscope and lysoTracker Red dyes. Finally, the transcriptome sequence was performed to analyze the total gene expression of these cells.

RESULTS

It was found that UMSC-P9 exhibited a reduced biological activity and showed an impaired mitochondrial morphology with disordered structure,  reduced mitochondrial crista, and mitochondrial fragments. They also displayed decreased mitochondrial membrane potential, antioxidative ability, tricarboxylic acid cycle activity and energy production. At the same time, apoptosis and ferroptosis were increased. In addition, UMSC-P9, relative to UMSC-P4, showed undegraded materials in their lysosomes, the enhancement in lysosomal membrane permeability, the reduction in autophagy and phagocytosis. Moreover, transcriptome sequence analysis also revealed a reduction of cell function, metabolism, mitochondrial biogenesis, DNA replication and repair, and an increase of gene expression related to cell senescence, cancer, diseases, and infection in UMSC-P9.

CONCLUSION

This study indicates that in vitro long-time culturing of MSCs can cause mitochondrial and lysosomal dysfunction, probably contributing to the decline of cell activity and cell aging. Therefore, the morphology and function of mitochondria and lysosomes can be regarded as two important parameters to monitor cell viability, and they can also serve as two important indicators for optimizing in vitro culture conditions.

Topical administration of the secretome derived from human amniotic epithelial cells ameliorates psoriasis-like skin lesions in mice

BACKGROUND

Psoriasis is a chronic inflammatory skin disease. Tissue stem cells have exhibited a therapeutic effect on psoriatic mice. However, the therapeutic effect of topical administration of the secretome derived from tissue stem cells on psoriasis has not been reported.

METHODS

The secretome from human amniotic epithelial cells (AEC-SC) and human umbilical cord mesenchymal stem cells (UMSC-SC) was topically administrated on the back of imiquimod-induced psoriasis-like mice. Subsequently, we observed the skin lesions and skin inflammation of psoriasis-like mice. Next, we further analyzed the paracrine factors in AEC-SC and UMSC-SC by protein chips. Lastly, the effect of the crucial paracrine factor was investigated by imiquimod-induced psoriasis-like mice.

RESULTS

We found that AEC-SC had a better therapeutic effect on attenuating psoriasis-like skin lesions including skin scales, skin redness and skin thickness than UMSC-SC, and it had a better regulatory effect on keratinocyte hyperproliferation and altered differentiation. Thus, we focused on AEC-SC. Further study showed that AEC-SC reduced the infiltration of neutrophils and interleukin-17-producing T cells. Next, the analysis of AEC-SC with protein chip revealed that the levels of anti-inflammatory factor interleukin-1 receptor antagonist (IL-1ra) were much higher in AEC-SC compared to that in UMSC-SC. More importantly, the beneficial effect of AEC-SC on psoriasis-like skin lesions and skin inflammation of mice were significantly impaired when neutralizing with IL-1ra antibody, while the recombinant human IL-1ra showed a less protective effect than AEC-SC.

CONCLUSIONS

The present study demonstrated that AEC-SC could efficiently ameliorate psoriasis-like skin lesions and skin inflammation and IL-1ra plays an essential role. Therefore, topical administration of AEC-SC may provide a novel strategy for treating psoriasis-like inflammatory skin diseases.

CSTF2 Promotes Hepatocarcinogenesis and Hepatocellular Carcinoma Progression via Aerobic Glycolysis

Background

The shortening of 3’ untranslated regions (3’UTRs) of messenger RNAs(mRNAs) by alternative polyadenylation (APA) is an important mechanism for oncogene activation. Cleavage stimulation factor 2 (CSTF2), an important regulator of APA, has been reported to have a tumorigenic function in urothelial carcinoma of the bladder and lung cancers. However, the tumor-promoting role of CSTF2 in hepatocellular carcinoma (HCC) and its underlying molecular mechanism remains unclear.

Methods

Multiple databases were used to analyze the expression level and prognostic value of CSTF2 in HCC. Function enrichment analysis was used to investigate the molecular mechanism of CSTF2 for the occurrence and development of HCC. The biological function in HCC cell lines in vitro was determined by CCK8, colony formation, Transwell migration, and invasion assay. Moreover, the tumorigenic function of CSTF2 in vivo was measured by a subcutaneous tumor formation or injecting four plasmids into a mouse tail vein within 5–7 s in an immunocompetent HCC mouse model. In addition, aerobic glycolysis in HCC cells was determined by measuring the extracellular acid rate (ECAR) and extracellular glucose and lactate levels.

Results

Bioinformatics analysis revealed that CSTF2 was overexpressed in HCC tissues. The high expression of CSTF2 was correlated with a poor prognosis and high histological grades. CSTF2 knockout inhibited the proliferation, migration, and invasion of HCC cells. In addition, CSTF2 knockout HCC cells failed to form tumors by a subcutaneous graft experiment. Furthermore, endogenous CSTF2 knockout attenuated hepatocarcinogenesis in an immunocompetent HCC mouse model. Function enrichment analysis suggested that the high expression of CSTF2 was associated with enhanced glycolysis. Moreover, we found that CSTF2 knockout reduced the level of the short 3’ UTR isoform of hexokinase 2 and increased its level of long 3’UTR. Furthermore, CSTF2 knockout inhibited ECAR levels, glucose uptake, and lactate production.

Conclusion

Our results indicated that CSTF2 is highly expressed in HCC and is correlated with a poor prognosis and high histological grade. The knockout of CSTF2 inhibits the tumorigenesis and procession of HCC both in vitro and in vivo. Moreover, CSTF2 is associated with enhanced glycolysis. Therefore, this study suggests that CSTF2 might be a new prognostic biomarker and therapeutic target for HCC.

Tumor-derived miR-378a-3p-containing extracellular vesicles promote osteolysis by activating the Dyrk1a/Nfatc1/Angptl2 axis for bone metastasis

Most prostate cancer (PCa)-related deaths are caused by progression to bone metastasis. Recently, the importance of extracellular vesicles (EVs) in pre-metastatic niche formation has been reported. However, whether and how tumor-derived EVs interact with bone marrow macrophages (BMMs) to release EV-delivered microRNAs to promote osteolysis and induce pre-metastatic niche formation for PCa bone metastasis remain unclear. Our in vitro and in vivo functional and mechanistic assays revealed that EV-mediated release of miR-378a-3p from tumor cells was upregulated in bone-metastatic PCa, maintaining low intracellular miR-378a-3p concentration to promote proliferation and MAOA-mediated epithelial-to-mesenchymal transition. Moreover, miR-378a-3p enrichment in tumor-derived EVs was induced by hnRNPA2B1 (a transfer chaperone) overexpression. After tumor-derived EVs were taken in by BMMs, enriched miR-378a-3p promoted osteolytic progression by inhibiting Dyrk1a to improve Nfatc1 (an osteolysis-related transcription factor) nuclear translocation, to activate the expression of downstream target gene Angptl2. As a feedback, increased Angptl2 secretion into the tumor environment promoted PCa progression. In conclusion, tumor-derived miR-378a-3p-containing EVs play a significant role in PCa bone metastasis by activating the Dyrk1a/Nfatc1/Angptl2 axis in BMMs to induce osteolytic progression, making miR-378a-3p a potential predictor of metastatic PCa. Reducing the release of miR-378a-3p-containing EVs or inhibiting the recruitment of miR-378a-3p into EVs can be a therapeutic strategy against PCa metastasis.

The evolving role of immune cells in prostate cancer

Prostate cancer is the most commonly diagnosed cancer and the second leading cause of cancer-related death among men in western countries. Androgen deprivation therapy (ADT) is considered the standard therapy for recurrent prostate cancer; however, this therapy may lead to ADT resistance and tumor progression, which seems to be regulated by epithelial-mesenchymal transition (EMT) and/or neuroendocrine differentiation (NED). In addition, recent data suggested the involvement of either adaptive or innate infiltrated immune cells in the initiation, progression, metastasis, and treatment of prostate cancer. In this review, we outlined the characteristics and roles of these immune cells in the initiation, progression, metastasis, and treatments of prostate cancer. We also summarized the current therapeutic strategies in targeting immune cells of the prostate tumor microenvironment.

CCL28 Downregulation Attenuates Pancreatic Cancer Progression Through Tumor Cell-Intrinsic and -Extrinsic Mechanisms

C-C motif chemokine ligand 28 (CCL28) has been reported to be pro-tumoral in several cancer types. However, the role of CCL28 in pancreatic ductal adenocarcinoma (PDAC) progression remains unclear. CCL28 mRNA expression in tumors from PDAC patients was found to be elevated as compared to normal pancreas. CCL28 expression was also negatively correlated with overall survival (OS) in pancreatic cancer patients. Our in vitro experiments showed that CCL28 knockdown impairs the proliferation of mouse pancreatic cancer cell line PAN02. Moreover, in both immunocompetent syngeneic mice and immunodeficient NOD-SCID mice, CCL28 deficiency significantly attenuated the growth of subcutaneous PAN02 tumors. In syngeneic mouse model, CCL28 downregulation remodeled the pancreatic tumor microenvironment by suppressing the infiltration of both regulatory T (Treg) cells, myeloid-derived suppressor cells, and activated pancreatic stellate cells, and upregulating the expression of lymphocyte cytotoxic proteins including perforin and granzyme B. In conclusion, our work demonstrates that CCL28 is a potential target for pancreatic cancer treatment and CCL28 blockade could inhibit tumor growth through both tumor-cell-intrinsic and extrinsic mechanisms.

Single-cell RNA sequencing reveals the epithelial cell heterogeneity and invasive subpopulation in human bladder cancer

Bladder cancer represents a highly heterogeneous disease characterized by distinct histological, molecular and clinical phenotypes, and a detailed analysis of tumor cell invasion and crosstalks within bladder tumor cells has not been determined. Here, we applied droplet-based single-cell RNA sequencing (scRNA-seq) to acquire transcriptional profiles of 36 619 single cells isolated from seven patients. Single cell transcriptional profiles matched well with the pathological basal/luminal subtypes. Notably, in T1 tumors diagnosed as luminal subtype, basal cells displayed characteristics of epithelial-mesenchymal transition (EMT) and mainly located at the tumor-stromal interface as well as micrometastases in the lamina propria. In one T3 tumor, muscle-invasive tumor showed significantly higher expression of cancer stem cell markers SOX9 and SOX2 than the primary tumor. We additionally analyzed communications between tumor cells and demonstrated its relevance to basal/luminal phenotypes. Overall, our single-cell study provides a deeper insight into the tumor cell heterogeneity associated with bladder cancer progression.

Prognosis and Immunotherapy Significances of a Cancer-Associated Fibroblasts-Related Gene Signature in Gliomas

As a cold tumor, malignant glioma has strong immunosuppression and immune escape characteristics. The tumor microenvironment (TME) provides the "soil" for the survival of malignant tumors, and cancer-associated fibroblasts (CAFs) are the architects of matrix remodeling in TME. Therefore, CAFs have potent regulatory effects on the recruitment and functional differentiation of immune cells, whereby they synthesize and secrete numerous collagens, cytokines, chemokines, and other soluble factors whose interaction with tumor cells creates an immunosuppressive TME. This consequently facilitates the immune escape of tumor cells. Targeting CAFs would improve the TME and enhance the efficacy of immunotherapy. Thus, regulation of CAFs and CAFs-related genes holds promise as effective immunotherapies for gliomas. Here, by analyzing the Chinese Glioma Genome Atlas and the Cancer Genome Atlas database, the proportion of CAFs in the tumor was revealed to be associated with clinical and immune characteristics of gliomas. Moreover, a risk model based on the expression of CAFs-related six-gene for the assessment of glioma patients was constructed using the least absolute shrinkage and selection operator and the results showed that a high-risk group had a higher expression of the CAFs-related six-genes and lower overall survival rates compared with those in the low-risk group. Additionally, patients in the high-risk group exhibited older age, high tumor grade, isocitrate dehydrogenase wildtype, 1p/19q non-codeletion, O-6-methylguanine-DNA methyltransferase promoter unmethylation and poor prognosis. The high-risk subtype had a high proportion CAFs in the TME of glioma, and a high expression of immune checkpoint genes. Analysis of the Submap algorithm indicated that the high-risk patients could show potent response to anti-PD-1 therapy. The established risk prediction model based on the expression of six CAFs-related genes has application prospects as an independent prognostic indicator and a predictor of the response of patients to immunotherapy.

hnRNPA2B1 Promotes Colon Cancer Progression via the MAPK Pathway

HNRNPA2B1, an RNA-binding protein, plays a key role in primary microRNA processing, alternative splicing, mRNA metabolism and transport. Interestingly, hnRNPA2B1 also works as an N6-methyladenosine (m6A) reader and is critical during tumorigenesis of various tissue types. However, its role in colon cancer is still unclear. In this study, we aimed to elucidate the biological functions of hnRNPA2B1 and to explore its underlying mechanisms in colon cancer. We examined the expression of hnRNPA2B1 in Oncomine and TCGA databases. Then verified the findings in colon cancer cells and clinical samples with western blotting and immunohistochemistry (IHC). We used CRISPR/Cas9 directed gene editing to knockout hnRNPA2B1 expression in human colon cancer cell line SW480 and HCT-116 and carried out both in vivo and in vitro experiments. The results were further confirmed by RNA-seq analyses. We found that hnRNPA2B1 significantly promoted colon cancer cell proliferation both in vitro and in vivo, while knockout of hnRNPA2B1 induced apoptosis and cell cycle arrest in SW480. RNA-seq analyses revealed that the ERK/MAPK pathway was activated by hnRNPA2B1 upregulation. In addition, both hnRNPA2B1 and MAPK pathway were activated in clinical colon cancer specimens and positively correlated. Mechanistically, hnRNPA2B1 appeared to be an upstream regulator of the ERK/MAPK pathway and inhibition of MAPK signaling blocked the effects of hnRNPA2B1. Taken together, our data demonstrated that the RNA-binding protein hnRNPA2B1 promotes cell proliferation and regulates cell cycle and apoptosis of human colon cancer by activating the ERK/MAPK signaling, which may provide a new insight into the development of hnRNPA2B1 as a potential therapeutic target for treatment of colon cancer.

Single-cell spatial transcriptomic analysis reveals common and divergent features of developing postnatal granule cerebellar cells and medulloblastoma

BACKGROUND

Cerebellar neurogenesis involves the generation of large numbers of cerebellar granule neurons (GNs) throughout development of the cerebellum, a process that involves tight regulation of proliferation and differentiation of granule neuron progenitors (GNPs). A number of transcriptional regulators, including Math1, and the signaling molecules Wnt and Shh have been shown to have important roles in GNP proliferation and differentiation, and deregulation of granule cell development has been reported to be associated with the pathogenesis of medulloblastoma. While the progenitor/differentiation states of cerebellar granule cells have been broadly investigated, a more detailed association between developmental differentiation programs and spatial gene expression patterns, and how these lead to differential generation of distinct types of medulloblastoma remains poorly understood. Here, we provide a comparative single-cell spatial transcriptomics analysis to better understand the similarities and differences between developing granule and medulloblastoma cells.

RESULTS

To acquire an enhanced understanding of the precise cellular states of developing cerebellar granule cells, we performed single-cell RNA sequencing of 24,919 murine cerebellar cells from granule neuron-specific reporter mice (Math1-GFP; Dcx-DsRed mice). Our single-cell analysis revealed that there are four major states of developing cerebellar granule cells, including two subsets of granule progenitors and two subsets of differentiating/differentiated granule neurons. Further spatial transcriptomics technology enabled visualization of their spatial locations in cerebellum. In addition, we performed single-cell RNA sequencing of 18,372 cells from Patched+/- mutant mice and found that the transformed granule cells in medulloblastoma closely resembled developing granule neurons of varying differentiation states. However, transformed granule neuron progenitors in medulloblastoma exhibit noticeably less tendency to differentiate compared with cells in normal development.

CONCLUSION

In sum, our study revealed the cellular and spatial organization of the detailed states of cerebellar granule cells and provided direct evidence for the similarities and discrepancies between normal cerebellar development and tumorigenesis.

Stepwise Induction of Inner Ear Hair Cells From Mouse Embryonic Fibroblasts via Mesenchymal- to-Epithelial Transition and Formation of Otic Epithelial Cells

Although embryonic stem cells or induced pluripotent stem cells are able to differentiate into inner ear hair cells (HCs), they have drawbacks limiting their clinical application, including a potential risk of tumourigenicity. Direct reprogramming of fibroblasts to inner ear HCs could offer an alternative solution to this problem. Here, we present a stepwise guidance protocol to induce mouse embryonic fibroblasts to differentiate into inner ear HC-like cells (HCLs) via mesenchymal-to-epithelial transition and then acquisition of otic sensory epithelial cell traits by overexpression of three key transcription factors. These induced HCLs express multiple HC-specific proteins, display protrusions reminiscent of ciliary bundle structures, respond to voltage stimulation, form functional mechanotransduction channels, and exhibit a transcriptional profile of HC signature. Together, our work provides a new method to produce functional HCLs in vitro, which may have important implications for studies of HC development, drug discovery, and cell replacement therapy for hearing loss.

A novel mouse model for liver metastasis of prostate cancer reveals dynamic tumour-immune cell communication

Objectives

In contrast to extensive studies on bone metastasis in advanced prostate cancer (PCa), liver metastasis has been under‐researched so far. In order to decipher molecular and cellular mechanisms underpinning liver metastasis of advanced PCa, we develop a rapid and immune sufficient mouse model for liver metastasis of PCa via orthotopic injection of organoids from PbCre⁺; rb1^f/f;p53^f/f mice.

Materials and Methods

PbCre⁺;rb1^f/f;p53^f/f and PbCre⁺;pten^f/f;p53^f/f mice were used to generate PCa organoid cultures in vitro. Immune sufficient liver metastasis models were established via orthotopic transplantation of organoids into the prostate of C57BL/6 mice. Immunofluorescent and immunohistochemical staining were performed to characterize the lineage profile in primary tumour and organoid‐derived tumour (ODT). The growth of niche‐labelling reporter infected ODT can be visualized by bioluminescent imaging system. Immune cells that communicated with tumour cells in the liver metastatic niche were determined by flow cytometry.

Results

A PCa liver metastasis model with full penetrance is established in immune‐intact mouse. This model reconstitutes the histological and lineage features of original tumours and reveals dynamic tumour‐immune cell communication in liver metastatic foci. Our results suggest that a lack of CD8⁺ T cell and an enrichment of CD163⁺ M2‐like macrophage as well as PD1⁺CD4⁺ T cell contribute to an immuno‐suppressive microenvironment of PCa liver metastasis.

Conclusions

Our model can be served as a reliable tool for analysis of the molecular pathogenesis and tumour‐immune cell crosstalk in liver metastasis of PCa, and might be used as a valuable in vivo model for therapy development.

The histone methyltransferase SETD2 modulates oxidative stress to attenuate experimental colitis

Epigenetic regulation disorder is important in the onset and pathogenesis of inflammatory bowel disease (IBD). SETD2, a trimethyltransferase of histone H3K36, is frequently mutated in IBD samples with a high risk of developing colorectal cancer (CRC). However, functions of SETD2 in IBD and colitis-associated CRC remain largely undefined. Here, we found that SETD2 modulates oxidative stress to attenuate colonic inflammation and tumorigenesis in mice. SETD2 expression became decreased in IBD patients and dextran sodium sulfate (DSS)-induced colitic mice. Setd2^Vil-KO mice showed increased susceptibility to DSS-induced colitis, accompanied by more severe epithelial barrier disruption and markedly increased intestinal permeability that subsequently facilitated inflammation-associated CRC. Mechanistically, we found that Setd2 depletion resulted in excess reactive oxygen species (ROS) by directly down-regulating antioxidant genes, which led to defects in barrier integrity and subsequently inflammatory damage. Moreover, overexpression of antioxidant PRDX6 in Setd2^Vil-KO intestinal epithelial cells (IECs) largely alleviated the overproductions of ROS and improved the cellular survival. Together, our findings highlight an epigenetic mechanism by which SETD2 modulates oxidative stress to regulate intestinal epithelial homeostasis and attenuate colonic inflammation and tumorigenesis. SETD2 might therefore be a pivotal regulator that maintains the homeostasis of the intestinal mucosal barrier.

SETD2 epidermal deficiency promotes cutaneous wound healing via activation of AKT/mTOR Signalling

Objectives

Cutaneous wound healing is one of the major medical problems worldwide. Epigenetic modifiers have been identified as important players in skin development, homeostasis and wound repair. SET domain–containing 2 (SETD2) is the only known histone H3K36 tri‐methylase; however, its role in skin wound healing remains unclear.

Materials and Methods

To elucidate the biological role of SETD2 in wound healing, conditional gene targeting was used to generate epidermis‐specific Setd2‐deficient mice. Wound‐healing experiments were performed on the backs of mice, and injured skin tissues were collected and analysed by haematoxylin and eosin (H&E) and immunohistochemical staining. In vitro, CCK8 and scratch wound‐healing assays were performed on Setd2‐knockdown and Setd2‐overexpression human immortalized keratinocyte cell line (HaCaT). In addition, RNA‐seq and H3K36me3 ChIP‐seq analyses were performed to identify the dysregulated genes modulated by SETD2. Finally, the results were validated in functional rescue experiments using AKT and mTOR inhibitors (MK2206 and rapamycin).

Results

Epidermis‐specific Setd2‐deficient mice were successfully established, and SETD2 deficiency resulted in accelerated re‐epithelialization during cutaneous wound healing by promoting keratinocyte proliferation and migration. Furthermore, the loss of SETD2 enhanced the scratch closure and proliferation of keratinocytes in vitro. Mechanistically, the deletion of Setd2 resulted in the activation of AKT/mTOR signalling pathway, while the pharmacological inhibition of AKT and mTOR with MK2206 and rapamycin, respectively, delayed wound closure.

Conclusions

Our results showed that SETD2 loss promoted cutaneous wound healing via the activation of AKT/mTOR signalling.

Single-cell analysis reveals urothelial cell heterogeneity and regenerative cues following cyclophosphamide-induced bladder injury

Cyclophosphamide is a commonly used chemotherapeutic drug to treat cancer with side effects that trigger bladder injury and hemorrhagic cystitis. Although previous studies have demonstrated that certain cell subsets and communications are activated to drive the repair and regeneration of bladder, it is not well understood how distinct bladder cell subsets function synergistically in this process. Here, we used droplet-based single-cell RNA sequencing (scRNA-seq) to profile the cell types within the murine bladder mucous layer under normal and injured conditions. Our analysis showed that superficial cells are directly repaired by cycling intermediate cells. We further identified two resident mesenchymal lineages (Acta2⁺ myofibroblasts and Cd34⁺ fibroblasts). The delineation of cell-cell communications revealed that Acta2⁺ myofibroblasts upregulated Fgf7 expression during acute injury, which activated Fgfr signaling in progenitor cells within the basal/intermediate layers to promote urothelial cell growth and repair. Overall, our study contributes to a more comprehensive understanding of the cellular dynamics during cyclophosphamide-induced bladder injury and may help identify important niche factors contributing to the regeneration of injured bladders.

Multilevel Regulation of β-Catenin Activity by SETD2 Suppresses the Transition from Polycystic Kidney Disease to Clear Cell Renal Cell Carcinoma

Patients with polycystic kidney disease (PKD) are at a high risk of developing renal cell carcinoma (RCC). However, little is known about genetic alterations or changes in signaling pathways during the transition from PKD to RCC. SET domain-containing 2 (SETD2) is a histone methyltransferase, which catalyzes tri-methylation of H3K36 (H3K36me3) and has been identified as a tumor suppressor in clear cell renal cell carcinoma (ccRCC), but the underlying mechanism remains largely unexplored. Here we report that knockout of SETD2 in a c-MYC-driven PKD mouse model drove the transition to ccRCC. SETD2 inhibited β-catenin activity at transcriptional and posttranscriptional levels by competing with β-catenin for binding promoters of target genes and maintaining transcript levels of members of the β-catenin destruction complex. Thus, SETD2 deficiency enhanced the epithelial-to-mesenchymal transition and tumorigenesis through the hyperactivation of Wnt/β-catenin signaling. Our findings reveal previously unrecognized roles of SETD2-mediated competitive DNA binding and H3K36me3 modification in regulating Wnt/β-catenin signaling during the transition from PKD to ccRCC. The novel autochthonous mouse models of PKD and ccRCC will be useful for preclinical research into disease progression. SIGNIFICANCE: These findings characterize multiple mechanisms by which SETD2 inhibits β-catenin activity during the transition of polycystic kidney disease to renal cell carcinoma, providing a potential therapeutic strategy for high-risk patients. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/13/3554/F1.large.jpg.

Regulation of Formation, Stemness and Therapeutic Resistance of Cancer Stem Cells

Over the past 20 years cancer stem cells (CSCs) have been proposed as key players in the tumorigenesis and progression, which are closely related to the initiation, metastasis and therapeutic resistance of cancer. Evidences have been provided that both genetic and epigenetic factors contribute to the regulation of the formation and stemness maintenance as well as the therapeutic resistance of CSCs via affecting various signal pathways. In addition, the interaction between CSCs and tumor microenvironment has also been revealed to be involved in the above-described processes. With the aim of targeting CSCs to improve treatment outcome, we herein discuss the mechanisms that orchestrate the characteristic of CSCs by the three elements and potential therapeutic strategies. We also summarize how several key regulatory factors function in the regulation of not only the formation and stemness maintenance, but also the therapeutic resistance of CSCs. Thus, future studies focusing on these key factors would be helpful for the development of novel drugs targeting CSCs.

Metal-Organic Framework Hybrids Aid Metabolic Profiling for Colorectal Cancer

Colorectal cancer (CRC) is the third most common fatal cancer worldwide, accounting for ≈10% of cancer-related mortality. Metabolic shift occurs from the very early stage during the development of CRC, which is of significant etiological and diagnostic importance toward precision medicine. Here, an advanced molecular tool to characterize the metabolic alterations in CRC, based on metal-organic framework (MOF) hybrids is reported. Consuming only 500 nL of plasma without any sample pretreatment, MOF hybrids yield direct metabolic fingerprints by laser desorption/ionization mass spectrometry in seconds. A diagnostic prediction model by a machine learning algorithm is constructed, to discriminate CRC patients from normal controls with an average area under the curve of 0.947 for the discovery cohort and 0.912 for the independent validation cohort. In addition, CRC-specific metabolic signature consisting of 34 potential biomarkers, based on the aforementioned diagnostic model is identified. The results advance the design of nanomaterial-based platforms for metabolic analysis and establish a new liquid biopsy tool for CRC screening compatible with the current clinical workflow in practice.

Discovery of extracellular vesicles derived miR-181a-5p in patient's serum as an indicator for bone-metastatic prostate cancer

Purpose: To identify extracellular vesicle (EV)-delivered microRNAs in the patient's serum as indicators for bone-metastatic prostate cancer.

Methods: First, the profiling change of serum EV-delivered miRNAs in patients with either benign prostatic hyperplasia (BPH), non-bone metastatic prostate cancer or bone-metastatic prostate cancer was detected by microRNA deep sequencing assay and microRNA-chip array assay, respectively. Second, the candidates were further confirmed using TaqMan microRNA assay in two independent validation cohorts of total 176 patients with either BPH, non-bone metastatic prostate cancer or bone metastatic prostate cancer to seek the most valuable microRNA(s).

Results: Through microRNA deep sequencing and microRNA-chip array, we found 4 prospective EV-delivered miRNAs including miR-181a-5p with significantly upregulated expression in bone metastatic groups than in non-bone metastatic prostate cancer groups (p < 0.05). In the validation cohorts, logistic regression analysis was performed to evaluate the diagnostic association of candidates with bone metastasis, which indicated that miR-181a-5p was significantly associated with bone metastatic prostate cancer. Furthermore, accuracy estimate of each candidate for the diagnosis of bone metastatic prostate cancer was quantified using the area under the receiver-operating characteristic curve (AUC), which identified miR-181a-5p as the best biomarker with the AUCs of 85.6% for diagnosis of prostate cancer and 73.8% for diagnosis of bone metastatic prostate cancer.

Conclusion: EV-delivered miR-181a-5p from patient's serum is a promising diagnostic biomarker for bone metastatic prostate cancer.

Single-cell analysis supports a luminal-neuroendocrine transdifferentiation in human prostate cancer

Neuroendocrine prostate cancer is one of the most aggressive subtypes of prostate tumor. Although much progress has been made in understanding the development of neuroendocrine prostate cancer, the cellular architecture associated with neuroendocrine differentiation in human prostate cancer remain incompletely understood. Here, we use single-cell RNA sequencing to profile the transcriptomes of 21,292 cells from needle biopsies of 6 castration-resistant prostate cancers. Our analyses reveal that all neuroendocrine tumor cells display a luminal-like epithelial phenotype. In particular, lineage trajectory analysis suggests that focal neuroendocrine differentiation exclusively originate from luminal-like malignant cells rather than basal compartment. Further tissue microarray analysis validates the generality of the luminal phenotype of neuroendocrine cells. Moreover, we uncover neuroendocrine differentiation-associated gene signatures that may help us to further explore other intrinsic molecular mechanisms deriving neuroendocrine prostate cancer. In summary, our single-cell study provides direct evidence into the cellular states underlying neuroendocrine transdifferentiation in human prostate cancer.

Targeted Delivery of CXCL9 and OX40L by Mesenchymal Stem Cells Elicits Potent Antitumor Immunity

Major obstacles in immunotherapies include toxicities associated with systemic administration of therapeutic agents, as well as low tumor lymphocyte infiltration that hampers the efficacies. In this study, we report a mesenchymal stem cell (MSC)-based immunotherapeutic strategy in which MSCs specifically deliver T/natural killer (NK) cell-targeting chemokine CXCL9 and immunostimulatory factor OX40 ligand (OX40L)/tumor necrosis factor superfamily member 4 (TNFSF4) to tumor sites in syngeneic subcutaneous and azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced spontaneous colon cancer mouse models. This approach generated potent local antitumor immunity by increasing the ratios of tumor-infiltrating CD8⁺ T and NK cells and production of antitumor cytokines and cytolytic proteins in the tumor microenvironment. Moreover, it improved the efficacy of programmed death-1 (PD-1) blockade in a syngeneic mouse model and significantly suppressed the growth of major histocompatibility complex class I (MHC class I)-deficient tumors. Our MSC-based immunotherapeutic strategy simultaneously recruits and activates immune effector cells at the tumor site, thus overcoming the problems with toxicities of systemic therapeutic agents and low lymphocyte infiltration of solid tumors.

Human Amniotic Epithelial Cells Alleviate a Mouse Model of Parkinson's Disease Mainly by Neuroprotective, Anti-Oxidative and Anti-Inflammatory Factors

Human amniotic epithelial cells (hAECs) have been reported to have neuroprotective roles in Parkinson's disease (PD) animal models. However, the molecular mechanism is not fully understood. The present study was designed to explore the possible mechanism by which hAECs ameliorate PD symptoms and the important paracrine factors produced by hAECs that attribute to the recovery of dopaminergic neurons. Thus, we performed in vivo and in vitro experiments with hAECs in PD models or lesioned dopaminergic neurons, respectively. First, hAECs were transplanted into the striatum of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mice and motor deficits were significantly attenuated. Second, the grafts prevented the loss of nigral dopaminergic neurons and promoted the outgrowth of neurites and striatal axon fibers in PD mice. In addition, decreased microglial activation, inflammatory factor levels and MPTP-induced excessive reactive oxygen species (ROS) levels were also observed in hAEC-treated PD mice. In vitro, we found that the conditioned medium (CM) from hAECs promoted the survival of mesencephalic dopaminergic neurons stimulated with 1-methyl-4-phenylpyridine (MPP⁺) and induced neurite outgrowth. Next, analysis of hAEC-CM with an antibody array of 507 soluble target proteins revealed that the levels of many neurotrophic factors, growth factors, neuronal cell adhesion molecule (NrCAM) and anti-inflammatory factors were evidently high. In addition, antibody neutralization experiments showed that many of these factors contributed to the survival and growth of dopaminergic neurons and neurite outgrowth. More importantly, we found that the anti-inflammatory factor interleukin-1 receptor antagonist (IL-1ra) also augmented the survival of dopaminergic neurons, demonstrating for the first time an anti-oxidative and anti-inflammatory role of hAECs in PD mice, which represents a novel molecular mechanism of hAECs in the treatment of PD. The molecular mechanism of hAECs recovering lesioned dopaminergic neurons and attenuating PD symptoms. First, hAECs secret many neurotrophic factors, growth factors, and neuronal cell adhesion molecule (NrCAM) which promote the growth of the damaged dopaminergic neurons and their neurites. Second, hAECs produce many anti-inflammatory factors and other factors contributing to reducing the activation of microglia and suppressing the neuroinflammation. Third, hAECs reduce the excessive ROS levels by upregulating some anti-oxidative signals.

Single-Cell Characterization of Malignant Phenotypes and Developmental Trajectories of Adrenal Neuroblastoma

Neuroblastoma (NB), which is a subtype of neural-crest-derived malignancy, is the most common extracranial solid tumor occurring in childhood. Despite extensive research, the underlying developmental origin of NB remains unclear. Using single-cell RNA sequencing, we generate transcriptomes of adrenal NB from 160,910 cells of 16 patients and transcriptomes of putative developmental cells of origin of NB from 12,103 cells of early human embryos and fetal adrenal glands at relatively late development stages. We find that most adrenal NB tumor cells transcriptionally mirror noradrenergic chromaffin cells. Malignant states also recapitulate the proliferation/differentiation status of chromaffin cells in the process of normal development. Our findings provide insight into developmental trajectories and cellular states underlying human initiation and progression of NB.

Derivation and propagation of spermatogonial stem cells from human pluripotent cells

OBJECTIVES

This study is designed to generate and propagate human spermatogonial stem cells (SSCs) derived from human pluripotent stem cells (hPSCs).

METHODS

hPSCs were differentiated into SSC-like cells (SSCLCs) by a three-step strategy. The biological characteristics of SSCLCs were detected by immunostaining with antibodies against SSC markers. The ability of self-renewal was measured by propagating for a long time and still maintaining SSCs morphological property. The differentiation potential of SSCLCs was determined by the generation of spermatocytes and haploid cells, which were identified by immunostaining and flow cytometry. The transcriptome analysis of SSCLCs was performed by RNA sequencing. The biological function of SSCLCs was assessed by xeno-transplantation into busulfan-treated mouse testes.

RESULTS

SSCLCs were efficiently generated by a 3-step strategy. The SSCLCs displayed a grape-like morphology and expressed SSC markers. Moreover, SSCLCs could be propagated for approximately 4 months and still maintained their morphological properties. Furthermore, SSCLCs could differentiate into spermatocytes and haploid cells. In addition, SSCLCs displayed a similar gene expression pattern as human GPR125⁺ spermatogonia derived from human testicular tissues. And more, SSCLCs could survive and home at the base membrane of seminiferous tubules.

CONCLUSION

SSCLCs were successfully derived from hPSCs and propagated for a long time. The SSCLCs resembled their counterpart human GPR125⁺ spermatogonia, as evidenced by the grape-like morphology, transcriptome, homing, and functional characteristics. Therefore, hPSC-derived SSCLCs may provide a reliable cell source for studying human SSCs biological properties, disease modeling, and drug toxicity screening.

β-Catenin inhibition shapes tumor immunity and synergizes with immunotherapy in colorectal cancer

In colorectal cancer, Wnt/β-catenin signaling is often aberrantly activated and associated with a T-cell-excluded phenotype which is a major obstacle for many immunotherapies. However, the effects of Wnt/β-catenin inhibition on tumor immunity and immunotherapy remain to be elucidated. In syngeneic mouse models of colorectal cancer, β-catenin/TCF inhibitor iCRT14 potently enhanced the infiltration of T and NK cells, without influencing their proliferation or the infiltration of most myeloid populations. Mechanistically, β-catenin inhibition upregulated while its overexpression suppressed the expression of T/NK cell-recruiting CXCR3 chemokines CXCL9/10/11 in both mouse and human colorectal cancer cells. Furthermore, iCRT14 treatment synergized with tumor vaccines or Treg cell ablation to achieve a complete inhibition of tumor growth in syngeneic models of CT26-OVA and MC38-S33Y.β-cat, respectively. Taken together, our work reveals that β-catenin inhibition shifts colorectal tumor microenvironment into a T-cell-inflamed phenotype and potentiates the efficacy of other immunotherapeutic strategies for colorectal cancer.

Metabolic heterogeneity in cancer: An overview and therapeutic implications

Recent research on cancer metabolism has revealed that individual tumors have highly heterogeneous metabolic profiles that contribute to the connective metabolic networks within the tumor and its environment. Indeed, tumor-associated cells types, including tumor cells, cancer-associated fibroblasts (CAFs) and immune cells, reprogram their metabolism in many different ways due to diverse genetic backgrounds and complex environmental stimuli. This intratumoral metabolic heterogeneity and the derived metabolic interactions play an instrumental role in cancer progression. Understanding how this heterogeneity occurs may provide promising therapeutic strategies. Here, we review the diverse metabolic profiles of several important cell subpopulations in tumors and their impact on tumor progression and discuss the consequent metabolic interactions as well as the related therapeutic concerns.

Abstract LB-087: Blockade of β-catenin-induced CCL28 suppresses gastric cancer progression via inhibition of Treg cell infiltration

Dysregulation of Wnt/β-catenin signaling is frequently observed in human gastric cancer. Elucidation of tumor immune microenvironment is essential for the understanding of tumorigenesis and the development of immunotherapeutic strategies. However, it remains unclear how β-catenin signaling regulates stomach tumor immune microenvironment. Our in vitro study unraveled CCL28 as a direct transcriptional target gene of β-catenin/T cell factor (TCF). Protein levels of β-catenin and CCL28 were positively correlated in human gastric adenocarcinoma. β-Catenin-activated CCL28 was able to recruit Regulatory T (Treg) cells in transwell migration assay. In a clinically relevant mouse gastric cancer model established by Helicobacter (H.) felis infection and MNU treatment, inhibition of β-catenin/TCF activity by a pharmacological inhibitor iCRT14 suppressed CCL28 expression and Treg cell infiltration in the stomach. Moreover, anti-CCL28 antibody attenuated Treg cell infiltration and tumor progression in H. felis/MNU mouse models. Diphtheria toxin (DT)-induced Treg cell ablation restrained gastric cancer progression in H. felis/MNU-treated DEREG (Foxp3-DTR) mice, clarifying the tumor-promoting role of Treg cells. Thus, the β-catenin-CCL28-Treg cell axis may serve as an important mechanism for immunosuppression of the stomach tumor microenvironment. Our findings highlighted an immunoregulatory role of β-catenin signaling in stomach tumors and the therapeutic potentials of CCL28 blockade for the treatment of gastric cancer.

Citation Format: Lu Ji, Helen He Zhu, Bin Ma, Wei-Qiang Gao. Blockade of β-catenin-induced CCL28 suppresses gastric cancer progression via inhibition of Treg cell infiltration [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-087.

CD16 expression on neutrophils predicts treatment efficacy of capecitabine in colorectal cancer patients

Background

Early detection of capecitabine-resistance could largely increase overall survival of colorectal cancer (CRC) patients. Previous studies suggested examination of immune cells in peripheral blood would help to predict efficacy of chemotherapy.

Methods

We examined the immunological characteristics of peripheral blood in CRC patients with capecitabine treatment. We analyzed the relationships between the abnormal immune cell population in capecitabine-resistance patients and major clinical features. Furthermore, RNA sequencing, analyses of cell surface marker expression and the correlations with other major immune cell populations were performed using this population to explore the possible function of these cells.

Results

The expression level of CD16 on neutrophils was down-regulated in capecitabine-resistant CRC patients. Patients with CD16^low/−neutrophils after capecitabine therapy had adverse clinical features. What’s important, the change of CD16 expression level on neutrophils appeared much earlier than CT scan. RNA sequencing revealed that CD16^low/−neutrophils in capecitabine-resistant patients had lower expression level of neutrophil-related genes, compared to CD16⁺neutrophils in capecitabine-sensitive patients, suggesting this CD16^low/−population might be immature neutrophils. Furthermore, the expression level of CD16 on neutrophils in patients with capecitabine treatment was positively correlated with the number of anti-tumor immune cell subsets, such as CD8⁺T cell, CD4⁺T cell, NK cell and monocyte.

Conclusions

Our findings indicated that CD16 expression on neutrophils in peripheral blood was a good prognostic marker for predicting efficacy of capecitabine in CRC patients.

Wnt/β-catenin signaling contributes to prostate cancer heterogeneity through reciprocal suppression of H3K27 trimethylation

Intratumoral heterogeneity remains as a major challenge in the treatment resistance of prostate cancer. Understanding the mechanism of prostate cancer heterogeneity is essential for developing effective therapies. In this study, we reported the heterogeneous activation of Wnt/β-catenin signaling in prostate cancer. We developed a Wnt/β-catenin signaling reporting system to directly characterize the differences between Wnt/β-catenin signaling active (GFP⁺) and inactive (GFP^-) cells. Compared to GFP^- cells, GFP⁺ cells demonstrated cancer stem cell properties with higher colony formation efficiency, slower cell cycle, higher resistance to docetaxel and higher expression of cancer stem cell markers. In addition, we found that Wnt/β-catenin signaling is negatively correlated with H3K27me3 levels. Further studies demonstrated that Wnt/β-catenin signaling affected H3K27me3 levels by regulating the expression of KDM6A, one of the H3K27me3 demethylases. H3K27me3 suppressed Wnt/β-catenin signaling by directly silencing LEF1 promoter. Together, our studies suggest that Wnt/β-catenin signaling makes a major contribution to prostate cancer heterogeneity and targeting both Wnt/β-catenin signaling active and inactive populations is essential for developing more effective therapies.

Di-Ras2 promotes renal cell carcinoma formation by activating the mitogen-activated protein kinase pathway in the absence of von Hippel-Lindau protein

Clear cell renal cell carcinoma (ccRCC) is one of the most common and lethal human urological malignancies in the world. One of the pathological drivers for ccRCC is the Ras family of small GTPases that function as "molecular switches" in many diseases including ccRCC. Among the GTPases in the Di-Ras family, DIRAS2 gene encodes a GTPase that shares 60% homology to Ras and Rap. Yet little is known about the biological function(s) of Di-Ras2 or how its activities are regulated. In this study, we focused on Di-Ras2, and determined its functions and underlying mechanism during formation of ccRCC. We found that Di-Ras2 was upregulated in ccRCC, and promoted the proliferation, migration and invasion of human ccRCC cells in the absence of von Hippel-Lindau protein (pVHL). Mechanistically, Di-Ras2 induces and regulates ccRCC formation by modulating phosphorylation of the downstream effectors and activating the Ras/mitogen-activated protein kinase (MAPK) signaling pathway. Moreover, Di-Ras2 interacts with E3 ubiquitin ligase, pVHL, which facilitates the ubiquitination and degradation of Di-Ras2. Together, these results indicate a potential function of Di-Ras2 as an oncogene in ccRCC, and these data provide a new perspective of the relationship between pVHL and the MAPK pathway in ccRCC tumorigenesis.

Loss of Setd2 promotes Kras-induced acinar-to-ductal metaplasia and epithelia-mesenchymal transition during pancreatic carcinogenesis

OBJECTIVE

SETD2, the sole histone H3K36 trimethyltransferase, is frequently mutated or deleted in human cancer, including pancreatic ductal adenocarcinoma (PDAC). However, whether SETD2/H3K36me3 alteration results in PDAC remains largely unknown.

DESIGN

TCGA(PAAD) public database and PDAC tissue array with SETD2/H3K36me3 staining were used to investigate the clinical relevance of SETD2 in PDAC. Furthermore, to define the role of SETD2 in the carcinogenesis of PDAC, we crossed conditional Setd2 knockout mice (Pdx^creSetd2^flox/flox) together with Kras^G12D mice. Moreover, to examine the role of SETD2 after ductal metaplasia, Crisp/cas9 was used to deplete Setd2 in PDAC cells. RNA-seq and H3K36me3 ChIP-seq were performed to uncover the mechanism.

RESULTS

SETD2 mutant/low expression was correlated with poor prognosis in patients with PDAC. Next, we found that Setd2 acted as a putative tumour suppressor in Kras-driven pancreatic carcinogenesis. Mechanistically, Setd2 loss in acinar cells facilitated Kras-induced acinar-to-ductal reprogramming, mainly through epigenetic dysregulation of Fbxw7. Moreover, Setd2 ablation in pancreatic cancer cells enhanced epithelia-mesenchymal transition (EMT) through impaired epigenetic regulation of Ctnna1. In addition, Setd2 deficiency led to sustained Akt activation via inherent extracellular matrix (ECM) production, which would favour their metastasis.

CONCLUSION

Together, our findings highlight the function of SETD2 during pancreatic carcinogenesis, which would advance our understanding of epigenetic dysregulation in PDAC. Moreover, it may also pave the way for development of targeted, patients-tailored therapies for PDAC patients with SETD2 deficiency.

Blockade of β-Catenin-Induced CCL28 Suppresses Gastric Cancer Progression via Inhibition of Treg Cell Infiltration

Dysregulation of Wnt/β-catenin signaling is frequently observed in human gastric cancer. Elucidation of the tumor immune microenvironment is essential for understanding tumorigenesis and for the development of immunotherapeutic strategies. However, it remains unclear how β-catenin signaling regulates the tumor immune microenvironment in the stomach. Here, we identify CCL28 as a direct transcriptional target gene of β-catenin/T-cell factor (TCF). Protein levels of β-catenin and CCL28 positively correlated in human gastric adenocarcinoma. β-Catenin-activated CCL28 recruited regulatory T (Treg) cells in a transwell migration assay. In a clinically relevant mouse gastric cancer model established by Helicobacter (H.) felis infection and N-methyl-N-nitrosourea (MNU) treatment, inhibition of β-catenin/TCF activity by a pharmacologic inhibitor iCRT14 suppressed CCL28 expression and Treg cell infiltration in the stomach. Moreover, an anti-CCL28 antibody attenuated Treg cell infiltration and tumor progression in H. felis/MNU mouse models. Diphtheria toxin-induced Treg cell ablation restrained gastric cancer progression in H. felis/MNU-treated DEREG (Foxp3-DTR) mice, clarifying the tumor-promoting role of Treg cells. Thus, the β-catenin-CCL28-Treg cell axis may serve as an important mechanism for immunosuppression of the stomach tumor microenvironment. Our findings reveal an immunoregulatory role of β-catenin signaling in stomach tumors and highlight the therapeutic potential of CCL28 blockade for the treatment of gastric cancer. SIGNIFICANCE: These findings demonstrate an immunosuppressive role of tumor-intrinsic β-catenin signaling and the therapeutic potential of CCL28 blockade in gastric cancer.

Decreased immunomodulatory and secretory capability of aging human umbilical cord mesenchymal stem cells in vitro

Mesenchymal stem cell therapy has drawn much attention as a promising therapeutic option for the treatment of different diseases. Due to insufficient cell population derived from freshly isolated tissues, in vitro propagation is required prior to clinical use. However, reduced cell viability of aging mesenchymal stem cell (MSCs) with repeated propagations has yet not be fully investigated, especially for the biological characteristics of immunoregulatory ability and paracrine factors. In this study, we compared the biological properties of human umbilical cord-MSCs (hUC-MSCs) at different passages, especially for immunomodulatory ability and secretions. Our results showed that hUC-MSCs at early passage (P2) and late passage (P8) exhibited similar morphology and surface marker expression, but hUC-MSCs at P8 displayed reduced proliferation and differentiation potential, immunoregulatory and secretory ability. In particular, hUC-MSCs at P2 and P5 could significantly suppress the population of proinflammatory Th1 and Th17 cell subsets and upregulate Treg cells, but not with hUC-MSCs at P8. For paracrine mechanism, higher level of secretions such as growth factors, cell adhesions, anti-inflammatory factors of hUC-MSCs were observed at P2 and P5 compared to that at P8. Therefore, it is essential to verify and validate the biological characteristics of hUC-MSCs that possess a good vitality before they are released for clinical use. Altogether, this study provides a rationale and two important parameters for how to select appropriate passage and vitality of MSCs for cell therapy.

Efficacy and Safety of Tranexamic Acid in Reducing Blood Loss of Lower Extremity Osteotomy in Peri-acetabulum and High Tibia: A Systematic Review and Meta-analysis

Objective

To assess the efficacy of tranexamic acid (TXA) in reducing total blood loss and transfusion, and the risk of thromboembolic events in patients undergoing periacetabular osteotomy (PAO) and high tibial osteotomy (HTO).

Methods

A systematic literature search was performed using PubMed, the Cochrane Central Register of Controlled Trials (CENTRAL), Embase (Ovid), Medline (Ovid), and Web of Science. ClinicalTrials.gov, American Academy of Orthopaedic Surgeons (AAOS), and Orthopaedic Trauma Association (OTA) conference proceedings were also searched to gain more eligible studies. The primary outcome measure was total blood loss and the blood transfusion rate of the TXA group versus control. The meta‐analysis was conducted using the RevMan 5.3 and Stata 14.0 software.

Results

A total of six studies were included involving 665 patients. Three studies were PAO, and the other three were HTO. The total blood loss in PAO (WMD, −330.49; 95% CI, −390.16 to −270.83; P < 0.001) and HTO (WMD, −252.50; 95% CI, −356.81 to −148.18; P < 0.001) and hemoglobin decline (WMD, −0.74; 95% CI, −1.09 to −0.38; P < 0.001) were significantly less in the TXA group than in the control group. TXA could reduce transfusion rates in PAO (RR, 0.26; 95% CI, 0.09 to 0.75; P = 0.01) but had no effect on HTO (RR, 0.20; 95% CI, 0.01 to 4.10; P = 0.30). The wound complications (RR, 0.62; 95% CI, 0.13 to 2.94; P = 0.54) had no significant difference between TXA and control groups.

Conclusions

This meta‐analysis demonstrated that TXA reduces total blood loss and hemoglobin decline in patients undergoing PAO and is safe, but it has little benefit in regard to reducing transfusion rates or wound complications in HTO, so TXA might be unwarranted for routine use for HTO.