SLC25A10, the mitochondrial dicarboxylate carrier, plays a crucial role in mitochondrial metabolism and protects against liver lipotoxicity. Moreover, its frequent amplification or mutation in cancers, particularly hepatocellular carcinoma (HCC), correlates with a poor prognosis. This study aimed to investigate the role of SLC25A10 in chemotherapy resistance in HCC and elucidate the underlying mechanisms. In this study, we found that hypoxia increased SLC25A10 expression with a preferential shift toward isoform 3 in HCC. This isoform interacts with the nuclear transporter IPO7 to translocate into the nucleus, where it binds to transcription factor CEBPB. This interaction upregulates the transcription of the anti-apoptotic gene BCL2A1, thereby enhancing HCC cell resistance to the chemotherapeutic agent, etoposide. Notably, disruption of the SLC25A10 isoform 3-IPO7 interaction significantly sensitized HCC tumors to etoposide in vivo, suggesting that targeting this interaction could be a promising therapeutic strategy to improve chemotherapy efficacy in HCC. This study reveals a novel nuclear function of the mitochondrial dicarboxylate carrier SLC25A10 in transcriptional regulation under hypoxic conditions, distinct from its canonical mitochondrial role. These findings expand our understanding of SLC25A10 biology and uncover a previously unrecognized mechanism that drives hypoxia-induced chemoresistance in HCC. Our findings suggest that SLC25A10 is a potential therapeutic target to overcome drug resistance in HCC.

Cancer-associated fibroblasts (CAFs) are activated fibroblasts that secrete numerous cytokines and chemokines to accelerate tumor progression. However, the mechanism underlying cytokine production by CAFs remains unclear. This study reports that CAFs isolated from colon cancer tissue, TGF-β1-induced CAFs, or HCT116 co-cultured CAFs secrete more cytokines and growth factors represented by IGF1, ELN, and SFRP2. Mechanistic investigations demonstrate that aerobic glycolysis metabolites fumarate and succinate can induce the transcription of IGF1, ELN, and SFRP2 in CAFs, while α-ketoglutarate (α-KG) can antagonize the induction effect of fumarate and succinate. Moreover, the downregulation of KDM6A in CAFs is observed compared to quiescent fibroblasts (NAFs). Additionally, integrated analysis of ATAC sequencing and RNA sequencing revealed altered chromatin structure during fibroblast activation. CUT-tag sequencing and co-IP assays demonstrate that KDM6A is bound to WDR5, facilitating its association with the COMPASS complex and the polycomb repressive complex at the expected target loci. Depletion of KDM6A disrupts the homeostasis between polycomb and COMPASS complexes, leading to an increase in the expression of IGF1, ELN, and SFRP2. However, the inhibitor GSK-J4, specific for both KDM6A and KDM6B, reduces IGF1 expression, indicating that KDM6B compensates for the demethylase function of KDM6A but cannot replace KDM6A to maintain the homeostasis of COMPASS and polycomb repressive complexes. These findings suggest a metabolism-related epigenetic mechanism for cytokine expression, where reduced KDM6A levels enhance the tumor-promoting effect of CAFs. This may provide insights into why colon cancer is more prevalent in men than in women, since KDM6A is an X-chromosome-associated gene.

Normal erythropoiesis requires the precise regulation of gene expression patterns, and transcription cofactors play a vital role in this process. Deregulation of cofactors has emerged as a key mechanism contributing to erythroid disorders. Through gene expression profiling, we found HES6 as an abundant cofactor expressed at gene level during human erythropoiesis. HES6 physically interacted with GATA1 and influenced the interaction of GATA1 with FOG1. Knockdown of HES6 impaired human erythropoiesis by decreasing GATA1 expression. Chromatin immunoprecipitation and RNA sequencing revealed a rich set of HES6- and GATA1-co-regulated genes involved in erythroid-related pathways. We also discovered a positive feedback loop composed of HES6, GATA1 and STAT1 in the regulation of erythropoiesis. Notably, erythropoietin (EPO) stimulation led to up-regulation of these loop components. Increased expression levels of loop components were observed in CD34+ cells of polycythemia vera patients. Interference by either HES6 knockdown or inhibition of STAT1 activity suppressed proliferation of erythroid cells with the JAK2V617F mutation. We further explored the impact of HES6 on polycythemia vera phenotypes in mice. The identification of the HES6-GATA1 regulatory loop and its regulation by EPO provides novel insights into human erythropoiesis regulated by EPO/EPOR and a potential therapeutic target for the management of polycythemia vera.

Objectives: Glutamic pyruvate transaminase (GPT2) catalyzes the reversible transamination between alanine and α-ketoglutarate (α-KG) to generate pyruvate and glutamate during cellular glutamine catabolism. The glutamate could be further converted to γ-aminobutyric acid (GABA). However, the role of GPT2 in tumor metastasis remains unclear. Methods: The wound healing and transwell assays were carried out to analyze breast cancer cell migration and invasion in vitro. Gene ontology analysis was utilized following RNA-sequencing to discover the associated molecule function. The mass spectrometry analysis following phosphoprotein enrichment was performed to discover the associated transcription factors. Most importantly, both the tail vein model and Mammary gland conditional Gpt2-/- spontaneous tumor mouse models were used to evaluate the effect of GPT2 on breast cancer metastasis in vivo. Results: GPT2 overexpression increases the content of GABA and promotes breast cancer metastasis by activating GABAA receptors. The delta subunit GABRD is necessary for the GPT2/GABA-induced breast cancer metastasis in xenograft and transgenic mouse models. Gpt2 knockout reduces the lung metastasis of the genetic Gpt2-/- breast cancer in mice and prolongs the overall survival of tumor burden mice. Mechanistically, GPT2-induced GABAA receptor activation increases Ca2+ influx by turning on its associated calcium channel, and the surged intracellular calcium triggers the PKC-CREB pathway activation. The activated transcription factor CREB accelerates breast cancer metastasis by upregulating metastasis-related gene expressions, such as PODXL, MMP3, and MMP9. Conclusion: In summary, this study demonstrates that GPT2 promotes breast cancer metastasis through up-regulated GABA activation of GABAAR-PKC-CREB signaling, suggesting it is a potential target for breast cancer therapy.

PURPOSE:Lesions with a high uptake of 18F-fluorodeoxyglucose (18F-FDG) on positron emission tomography-computed tomography (PET-CT) can be benign and malignant. New radiotracers, such as the gallium 68 (68Ga)-labeled fibroblast activation protein inhibitor 4 (FAPI-04), could be used to diagnose colorectal carcinoma. This study aimed to evaluate the efficacy of 68Ga-FAPI-04 PET in differentiating benign from malignant 18F-FDG-avid colorectal lesions. METHODS AND MATERIALS:An azoxymethane/dextran sodium sulfate (AOM/DSS)-induced rat colorectal tumor model was developed. Double-tracer 68Ga-FAPI-04 and 18F-FDG PET-CT were applied in the rat model and 22 patients. The PET-CT data were analyzed with enteroscopy, histopathologic observations, immunohistochemistry (IHC) staining, and radioautography results. One hundred seventy-two patients with pathologically confirmed colorectal lesions were enrolled in FAP IHC staining. RESULTS:We found that 68Ga-FAPI-04 PET-CT imaging accurately distinguished the malignant from benign inflammatory lesions in an AOM/DSS-induced rat colorectal tumor model. Of 22 patients with gastric cancer but without colorectal carcinoma, 8 had 18F-FDG uptake in the colorectum, but 68Ga-FAPI-04 PET was negative in these sites. An inflammatory lesion or adenoma did not interfere with 68Ga-FAPI-04 PET imaging. Among the 18F-FDG-avid colorectal lesions, 80 of 94 pathologically malignant lesions (85.1%) were FAP-positive, and only 16 of the 78 premalignant or benign lesions (20.5%) had a weak 68Ga-FAPI-04 uptake. CONCLUSIONS:68Ga-FAPI-04 PET-CT could be used to distinguish between benign and malignant 18F-FDG-avid colorectal lesions.

Extramedullary infiltration (EMI) is a concomitant manifestation that may indicate poor outcome of acute myeloid leukemia (AML). The underlying mechanism remains poorly understood and therapeutic options are limited. Here, we employed single-cell RNA sequencing on bone marrow (BM) and EMI samples from a patient with AML presenting pervasive leukemia cutis. A complement C1Q+ macrophage-like leukemia subset, which was enriched within cutis and existed in BM before EMI manifestations, was identified and further verified in multiple patients with AML. Genomic and transcriptional profiling disclosed mutation and gene expression signatures of patients with EMI that expressed high levels of C1Q. RNA sequencing and quantitative proteomic analysis revealed expression dynamics of C1Q from primary to relapse. Univariate and multivariate analysis demonstrated adverse prognosis significance of C1Q expression. Mechanistically, C1Q expression, which was modulated by transcription factor MAF BZIP transcription factor B, endowed leukemia cells with tissue infiltration ability, which could establish prominent cutaneous or gastrointestinal EMI nodules in patient-derived xenograft and cell line-derived xenograft models. Fibroblasts attracted migration of the C1Q+ leukemia cells through C1Q-globular C1Q receptor recognition and subsequent stimulation of transforming growth factor β1. This cell-to-cell communication also contributed to survival of C1Q+ leukemia cells under chemotherapy stress. Thus, C1Q served as a marker for AML with adverse prognosis, orchestrating cancer infiltration pathways through communicating with fibroblasts and represents a compelling therapeutic target for EMI.

Dear editor: Our recent research has found that the kynurenine derivative 3-HAA was lower in tumour cells due to the downregulation of its synthetic enzyme kynurenine 3-monooxygenase (KMO), and overexpression of KMO suppressed hepatocellular carcinoma (HCC) tumour formation and tumour growth by increasing endogenous 3-HAA. It is well known that kynurenine promotes tumour growth by directly binding to the aryl hydrocarbon receptor.1-3 The 3-hydroxyanthranilic acid (3-HAA), a derivative of kynurenine, was reported to induce apoptosis by upregulating phosphatases.4 However, the metabolism and function of kynurenine derivatives largely remain unclear. Here, we report our novel findings related to kynurenine metabolism. 3-HAA is decreased in tumour cells. Tryptophan catabolites were first analysed in clinical HCCs. The concentration of kynurenine catabolite 3-HAA decreased in both HCC and oesophageal carcinomas compared to the matched paratumour tissues (Figure 1A; Figure S1A). Conversely, the concentration of tryptophan and kynurenine was higher in these HCCs and oesophageal carcinomas than in the matched paratumour tissues, respectively. Consistent with this observation, the concentration of 3-HAA was also lower in seven HCC cell lines tested than in normal hepatic cells, whereas the content of tryptophan and kynurenine increased in these tested HCC cell lines (Figure 1B). The immunohistochemistry analysis further confirmed lower 3-HAA content in clinical HCC tissues than in adjacent non-cancerous tissues (Figure 1C). Metabolic flux analysis revealed tryptophan metabolised to kynurenine but not 3-hydroxykynurenine (3-HK) or 3-HAA in HCC cells, and the newly generated kynurenine was secreted into the culture medium (Figure 1D), suggesting 3-HAA is decreased in tumours, at least in HCCs and oesophageal carcinomas. Upregulation of KMO increases 3-HAA. To determine whether the metabolic enzymes regulate 3-HAA concentration, we assessed the expression of 3-HAA-related enzymes in HCC cells. The immunoblotting and immunohistochemistry analysis showed that KMO and kynureninase (KYNU) were downregulated in HCC cells and tissues. In contrast, the indoleamine 2,3-dioxygenase 1 (IDO1) and tryptophan 2,3-dioxygenase (TDO2) was upregulated (Figure 2A,B). This finding was consistent with the HCC expression profile in the TCGA database (Figure 2C). Moreover, both KMO and KYNU expression (www.gtexportal.org) are commonly downregulated in tumours originated from tissues abundantly expressing KMO and KYNU. These tumours include lung, kidney, and liver carcinomas, which are the top 10 tumours worldwide in terms of death (Figure 2D). In addition, overexpression of KMO significantly increased the concentration of 3-HAA in HCC SMMC7721 cells, but not the 3-HK, picolinate (PA), or quinolinate (QA; Figure 2E). The hydroxyanthranilate-3,4-dioxygenase (HAAO) knockdown had similar effects on the levels of these metabolites (Figure 2F). KMO overexpression inhibits tumour formation by inducing apoptosis. Functionally, either overexpression of KMO or knockdown of HAAO inhibited cell growth of HCC cells in vitro by increasing apoptosis (Figure 3A,B). Only the apoptosis inhibitor zVAD restored growth of HCC cells following 3-HAA treatment or overexpressing KMO (Figure 3C,D). Moreover, KMO overexpression suppressed tumour formation and tumour growth in the HCC xenograft nude mice model (Figure 3E; Figure S2A). Remarkably, the Kaplan–Meier survival analysis showed that HCC patients with high KMO expression had a prolonged disease-free survival than patients with low KMO expression (Figure 3F). The 3-HAA treatment significantly inhibited HCC cell growth and colony formation (Figure 3G; Figure S2B). Moreover, 3-HAA but not kynurenine slowed tumour growth in a CDX model and in a patient-derived xenograft (PDX) model (Figures S2C and 3H), suggesting KMO overexpression inhibits tumour formation and tumour growth via its catabolite 3-HAA. Through gene expression profiling, real-time PCR and immunoblotting, the top two upregulated genes DUSP6 and IGFBP1 were selected for further study (Figure 3I,J). However, the clinical data showed that the overall survival of HCC patients was only associated with the expression level of DUSP6, but not IGFBP1 (Figure 3K; Figure S2D). Patients expressing a high level of DUSP6 showed a more prolonged overall survival than patients expressing a low level of DUSP6 (Figure 3K), and the corrective analysis with the clinical characteristics also supported this finding (Figure S2E). Also, we demonstrated that DUSP6 mediates 3-HAA-induced tumour cell apoptosis via ERK signalling (Figure 3L,M; Figure S2F,G), which was consistent with our previous finding.4 According to the fact that 3-HAA activates transcription factor YY1,4, 5 closer analysis of the DUSP6 promoter region using online-based prediction tools6, 7 revealed a novel potential YY1 binding DNA fragment at positions −1145 to −1134, which was distinct from the reported consensuses binding sequence.8 This finding was further confirmed by a luciferase assay and ChIP-QPCR (Figure S2H,I). The TUNEL assay demonstrated that 3-HAA-induced apoptosis was reduced in SMMC7721 cells depleted of YY1, overexpression of DUSP6 restored the apoptosis suppressed by YY1 depletion (Figure S2J). KMO enhances the inhibition effect of IDO1 inhibitor on HCC growth. The various HCC mouse models were implemented to further evaluate the potential application of KMO target in clinics. As shown in Figure 4A, DUSP6 knockdown reversed KMO-mediated suppression of tumour growth in SMMC7721 xenografts. More impressively, KMO overexpression reduced the tumour numbers and prolonged the survival in a transposon HCC mouse model. DUSP6 depletion promoted tumour formation and shorten mice survival, and KMO overexpression had little effect on tumour formation and mice survival after DUSP6 knockdown (Figure 4B). Most importantly, KMO enhances the effect of IDO1 inhibitor Epacadostat to suppress HCC xenograft growth in an immune-competent mouse model (Figure 4C). In the meantime, the combination of KMO overexpression with IDO1 inhibitor Epacadostat also inhibited the HCC tumour growth and prolonged the survival of mice bearing transposon-induced HCCs (Figure 4D). In brief, this study reveals that both KMO and its substrate 3-HAA decreases in HCC cells and HCC tissues. The KMO overexpression as well as 3-HAA treatment reverses the tumour-promoting effect of kynurenine and significantly improves the efficacy of IDO1/2 inhibitors on HCC xenografts (Figure 4E). These findings show that downregulation of KMO appears to be essential for HCC growth, suggesting the kynurenine metabolic enzyme KMO is a promising therapeutic target for HCC. Not applicable. The authors declare that they have no competing interests. The authors thank Profs. Shimin Zhao (Fudan University School of Biology) and Weiwei Yang (Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Science) for useful discussions. Ministry of Science and Technology of the People's Republic of China, Grant Number: 2018YFC1313205; Shanghai Committee of Science and Technology, Grant Number: 11DZ2260200, 20JC1410100; National Natural Science Foundation of China, Grant Number: 81572300, 81872342. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Background: Lesions with a high uptake of 18-fluorodeoxyglucose(18F-FDG) on positron emission tomography / computed tomography (PET/CT) can be both benign and malignant. New radiotracers such as the gallium-68(68Ga) labeled fibroblast activation protein inhibitor-4(FAPI-04) could be used to diagnostic colorectal carcinoma. This study aimed to evaluate the efficacy of 68Ga-FAPI-04 PET in differentiating benign from malignant in 18F-FDG-avid colorectal lesions.Methods: An azoxymethane/dextran sodium sulfate (AOM/DSS) induced rat colorectal tumor model was developed. Double tracer 68 Ga-FAPI-04 and 18F-FDG PET/CT were acquired for the rat model and for 22 patients. The PET/CT findings were compared with enteroscopy, histopathological specimens, immunohistochemistry (IHC) staining, and radioautography. A total of 172 patients with pathologically confirmed colorectal lesions were enrolled in FAP IHC staining.Results: 68Ga-FAPI-04 PET/CT imaging accurately distinguished the malignant from benign inflammatory lesions in an AOM/DSS-induced rat colorectal tumor model. Eight out of 22 gastric cancer patients without colorectal carcinoma had 18F-FDG-avid colorectal lesions, but they were all negative in 68Ga-FAPI-04 PET imaging. An inflammatory lesion or adenoma did not interfere with 68Ga-FAPI-04 PET imaging. Most pathologically malignant lesions within the 18F-FDG-avid colorectal lesions(85.1%, 80 out of 94) were FAP-positive. However, only 20.5%(16 out of 78) of the premalignant or benign lesions had a week 68Ga-FAPI-04 uptake. Conclusion: 68Ga-FAPI-04 PET/CT could be used to distinguish between benign and malignant in 18F-FDG-avid colorectal lesions.Funding Information: This study was supported by grants from the Ministry of Science and Technology of the People's Republic of China (2018YFC1313205), the Shanghai Committee of Science and Technology (11DZ2260200) (20JC1410100), and the National Natural Science Foundation of China (81572300) (81872342) to Dr. Mi; the National Natural Science Foundation of China (81801725) to Dr. Shangguan.Declaration of Interests: The authors state that no conflict of interest to disclose.Ethics Approval Statement: This study received animal ethics board approval at Shanghai Jiao Tong University School of Medicine; clinical ethics board approval at the Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine. The ethical committee of the Ruijin Hospital approved the human tissue collection. Written informed consent was obtained from all patients to use the endoscopic or surgical pathological tissue for this study.

Background: Lesions with a high uptake of 18-fluorodeoxyglucose(18F-FDG) on positron emission tomography / computed tomography (PET/CT) can be both benign and malignant. New radiotracers such as the gallium-68(68Ga) labeled fibroblast activation protein inhibitor-4(FAPI-04) could be used to diagnostic colorectal carcinoma. This study aimed to evaluate the efficacy of 68Ga-FAPI-04 PET in differentiating benign from malignant in 18F-FDG-avid colorectal lesions. Methods: An azoxymethane/dextran sodium sulfate (AOM/DSS) induced rat colorectal tumor model was developed. Double tracer 68 Ga-FAPI-04 and 18F-FDG PET/CT were acquired for the rat model and for 22 patients. The PET/CT findings were compared with enteroscopy, histopathological specimens, immunohistochemistry (IHC) staining, and radioautography. A total of 172 patients with pathologically confirmed colorectal lesions were enrolled in FAP IHC staining. Results: 68Ga-FAPI-04 PET/CT imaging accurately distinguished the malignant from benign inflammatory lesions in an AOM/DSS-induced rat colorectal tumor model. Eight out of 22 gastric cancer patients without colorectal carcinoma had 18F-FDG-avid colorectal lesions, but they were all negative in 68Ga-FAPI-04 PET imaging. An inflammatory lesion or adenoma did not interfere with 68Ga-FAPI-04 PET imaging. Most pathologically malignant lesions within the 18F-FDG-avid colorectal lesions(85.1%, 80 out of 94) were FAP-positive. However, only 20.5%(16 out of 78) of the premalignant or benign lesions had a week 68Ga-FAPI-04 uptake. Conclusion: 68Ga-FAPI-04 PET/CT could be used to distinguish between benign and malignant in 18F-FDG-avid colorectal lesions. Funding Information: This study was supported by grants from the Ministry of Science and Technology of the People's Republic of China (2018YFC1313205), the Shanghai Committee of Science and Technology (11DZ2260200) (20JC1410100), and the National Natural Science Foundation of China (81572300) (81872342) to Dr. Mi; the National Natural Science Foundation of China (81801725) to Dr. Shangguan. Declaration of Interests: The authors state that no conflict of interest to disclose. Ethics Approval Statement: This study received animal ethics board approval at Shanghai Jiao Tong University School of Medicine; clinical ethics board approval at the Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine. The ethical committee of the Ruijin Hospital approved the human tissue collection. Written informed consent was obtained from all patients to use the endoscopic or surgical pathological tissue for this study.

Background: FDG high-uptake lesions indicate not only carcinoma but also benign lesions. The 68Ga-labelled FAPI was accumulated in various tumors. However, it’s unclear about the capacity of FAPI-PET in identifying malignant tumors from benign lesions.Methods: An AOM/DSS-induced rat colorectal tumor model was established. A double PET/CT tracer of 68Ga-FAPI-04 and 18F-FDG was used in the clinical trial and rat colorectal tumor model. Immunohistochemistry staining, enteroscopy, and radioautography were performed in this study.Results: Eight out of 22 patients had 18F-FDG-avid colorectal lesions, but they were negative in 68Ga-FAP-04 PET imaging. 68Ga-FAPI PET imaging distinguishes neoplasia from inflammatory lesions in an AOM/DSS-induced rat colorectal tumor model, and FAPI accumulation gradually increases along with tumor progression. Moreover, the clinical study demonstrated that only 20.5% (16 out of 78) of premalignant/benign lesions were weak FAP-positive. However, most cancer patients (85.1%, 80 out of 94) were FAP-positive, which further supported the above findings. Conclusion: The 68Ga-FAPI-04 PET distinguishes malignant tumors from inflammatory lesions by detecting FAP in a rat colorectal tumor model and the clinics, suggesting that 68Ga-FAPI-04 PET is a better diagnostic tool than 18F-FDG PET, at least to colorectal cancer patients.Funding Information: This study was supported by grants from the Ministry of Science and Technology of the People's Republic of China (2018YFC1313205), the Shanghai Committee of Science and Technology (11DZ2260200) (20JC1410100) and the National Natural Science Foundation of China (81572300) (81872342) to Dr. Mi; the National Natural Science Foundation of China (81801725) to Dr. Shangguan. Declaration of Interests: The authors state that no conflict of interest to disclose.Ethics Approval Statement: This study received animal ethics board approval at Shanghai Jiao Tong University School of Medicine, and clinical ethics board approval at the Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine.

肿瘤相关成纤维细胞(cancer-associated fibroblast,CAF)是肿瘤组织中数目最多的一种基质细胞,对肿瘤的发生发展起着重要作用.该文利用流式细胞术(flow cytometry,FCM)对比分析肿瘤相关成纤维细胞和非活化成纤维细胞(non-activated fibroblast,NAF)两者在细胞增殖和DNA倍性等方面的差异.在细胞形态学观察和细胞计数的基础上,通过PI、EdU和Ki-67等染色后利用FCM进行定量检测,并采用GraghPad软件对获得的数据进行统计分析.研究表明,与NAF细胞相比,CAF细胞增殖减缓,细胞周期在Go/G1期被阻滞,其差异具有统计学意义(P＜0.05).该文首次利用FCM量化CAF细胞的生物学特性,尝试为进一步机制的研究提供理论依据.

Background The 68 Ga-labelled FAPI provides new oncology imaging option other than 18 F-FDG-PET. However, it's unclear about whether the FAPI-PET distinguishes malignancy from benign lesions. Methods We established an AOM/DSS-induced rat colorectal tumor model. A double PET/CT tracer of 68 Ga-FAPI-04 and 18 F-FDG was used in the rat colorectal tumor model. Histological examination, immunohistochemistry staining, and radioautography were performed in this study. Results 68 Ga-FAPI PET imaging distinguishes neoplasia from inflammatory lesions in an AOM/DSS-induced rat colorectal tumor model, and FAPI accumulation gradually increases along with tumor progression. An inflammatory lesion did not interfere with 68 Ga-FAPI PET imaging. Conclusion The 68 Ga-FAPI-04 PET distinguishes malignant tumors from inflammatory lesions by detecting FAP in a rat colorectal tumor model, suggesting that 68 Ga-FAPI-04 PET is a better diagnostic tool than 18 F-FDG PET, at least to colorectal cancer patients.

OBJECTIVES:We aimed to investigate the role of [68Ga]FAPI-04 and [18F]FDG dual-tracer PET/CT for the initial assessment of gastric cancer and to explore the factors associated with their uptake. METHODS:This study enrolled 62 patients with histopathologically confirmed gastric cancer. We compared the diagnostic performance of [68Ga]FAPI-04, [18F]FDG, and combined dual-tracer PET/CT. The standardized uptake value (SUV) and tumor-to-background ratio (TBR) were also measured, and the factors that influence tracer uptake were analyzed. RESULTS:[68Ga]FAPI-04 PET/CT detected more primary lesions (90.3% vs 77.4%, p = 0.008) and peritoneal metastases (91.7% vs 41.7%, p = 0.031) and demonstrated higher SUVmax and TBR values (p < 0.001) of primary lesions compared to [18F]FDG PET/CT. Dual-tracer PET/CT significantly improved the diagnostic sensitivity for the detection of distant metastases, compared with stand-alone [18F]FDG (97.1% vs 73.5%, p = 0.008) or [68Ga]FAPI-04 (97.1% vs 76.5%, p = 0.016) PET/CT. Subsequently, treatment strategies were changed in nine patients following [68Ga]FAPI-04 and [18F]FDG dual-tracer PET/CT. Nevertheless, [68Ga]FAPI-04 uptake was primarily influenced by the size and invasion depth of the tumor. Both [68Ga]FAPI-04 and [18F]FDG PET/CT showed limited sensitivity for detecting early gastric cancer (EGC) (37.5% vs 25.0%, p > 0.05). CONCLUSIONS:In this initial study, [68Ga]FAPI-04 and [18F]FDG dual-tracer PET/CT were complementary and improved sensitivity for the detection of distant metastases pre-treatment in gastric cancer and could improve treatment stratification in the future. [68Ga]FAPI-04 had limited efficacy in detecting EGC. KEY POINTS:• [68Ga]FAPI-04 and [18F]FDG dual-tracer PET/CT are complementary to each other for improving diagnostic sensitivity in the initial evaluation of distant metastases from gastric cancer. • [68Ga]FAPI-04 PET/CT showed limited sensitivity in detecting EGC. • Need for further validation in a larger multi-centre prospective study.

The 3-hydroxyanthranilic acid (3-HAA), a derivative of kynurenine, was reported to suppress tumor growth. However, the function of 3-HAA largely remains unclear. Here, we report that 3-hydroxyanthranilic acid (3-HAA) is lower in tumor cells, while adding exogenous 3-HAA induces apoptosis in hepatocellular carcinoma by binding YY1. This 3-HAA binding of YY1 leads to phosphorylation of YY1 at the Thr 398 by PKCζ, concomitantly enhances YY1 chromatin binding activity to increase expression of target genes. These findings demonstrate that 3-HAA is a ligand of YY1, suggesting it is a promising therapeutic candidate for HCC.

Sorafenib is the FDA-approved first-line target drug for HCC patients. However, sorafenib only confers 3–5 months of survival benefit with <30% of HCC patients. Thus, it is necessary to develop a sensitizer for hepatocellular carcinoma (HCC) to sorafenib. Here, we report that in representative HCC cell lines (SMMC-7721 and PLC8024) that are insensitive to sorafenib, 3-HAA (50 μM) significantly enhances cell sensitivity to sorafenib to an extent that could not be explained by additive effects. In nude mice carrying HCC xenograft, tumor growth is inhibited by sorafenib (10 mg/kg/day) or 3-HAA (100 mg/kg/day) alone. When used in combination, the treatment effectively prevents the xenograft from growing. In a set of mechanistic experiments, we find enhanced AKT activation and increased proportion of CD44 + CD133 + cells in sorafenib-resistant HCC cells and tissues. The proportion of CD44 + CD133 + cells is reduced upon 3-HAA treatment in both cultured cells and mouse xenografts, suggesting that 3-HAA could decrease the stemness of HCC. We also detect decreased phosphorylation of AKT, a regulator of the GSK3β/β-catenin signaling upon 3-HAA treatment. The AKT activator SC79 activates GSK3 β/β-catenin signaling while the Wnt inhibitor XAV-939 abolishes 3-HAA inhibition of HCC growth in vitro and in mice. The current study demonstrates that 3-HAA sensitizes HCC cells to sorafenib by reducing tumor stemness, suggesting it is a promising molecule for HCC therapy.

Calcium channel TRPV6 upregulation is associated with poor prognosis of breast cancer by promoting invasion and metastasis, and TRPV6 is a potential target for breast cancer therapy. However, the mechanism by which TRPV6 promotes breast metastasis remains unclear. Here, we report that TRPV6 expression is upregulated in metastatic breast cancers and that TRPV6 overexpression or upregulation accelerates primary breast cancer cell migration. In contrast, TRPV6 suppression decreases cell migration. Mechanistically, TRPV6 activates NFATC2 by increasing NFATC2IP phosphorylation at Ser204, and CDK5 is a candidate kinase that may perform this phosphorylation. Consequently, activated NFATC2 increases breast cancer metastasis by upregulating ADAMTS6 expression. These observations suggest that TRPV6 increases NFATC2 transcriptional activity by increasing NFATC2IP phosphorylation, which consequently upregulates ADAMTS6 expression to promote breast cancer metastasis.

Tryptophan metabolism is an essential regulator of tumor immune evasion. However, the effect of tryptophan metabolism on cancer cells remains largely unknown. Here, we find that tumor cells have distinct responses to tryptophan deficiency in terms of cell growth, no matter hepatocellular carcinoma (HCC) cells, lung cancer cells, or breast cancer cells. Further study shows that ERRFI1 is upregulated in sensitive HCC cells, but not in resistant HCC cells, in response to tryptophan deficiency, and ERRFI1 expression level positively correlates with HCC patient overall survival. ERRFI1 knockdown recovers tryptophan deficiency-suppressed cell growth of sensitive HCC cells. In contrast, ERRFI1 overexpression sensitizes resistant HCC cells to tryptophan deficiency. Moreover, ERRFI1 induces apoptosis by binding PDCD2 in HCC cells, PDCD2 knockdown decreases the ERRFI1-induced apoptosis in HCC cells. Thus, we conclude that ERRFI1-induced apoptosis increases the sensitivity of HCC cells to tryptophan deficiency and ERRFI1 interacts with PDCD2 to induce apoptosis in HCC cells.

Background Kynurenine, a metabolite of tryptophan, promotes immune tolerance in development and tumor evasion by binding to the aryl hydrocarbon receptor (AHR). However, the kynurenine catabolic enzyme IDO1 inhibitors fail in clinical trials. Methods The LC-MS/MS and GC-MS/MS were performed to measure the concentration of tryptophan metabolites. The PCX model, PDX model, and transposon liver cancer models were used to evaluate the effects of 3-HAA, DUSP6, and YY1 on HCC tumor formation and/or tumor growth. Results 3-hydroxyanthranilic acid (3-HAA) induced HCC apoptosis and reduced xenografted tumor growth, the survival of the transposon HCC mice, and synergized with IDO1 inhibitor on HCC growth in vivo . Overexpression of 3-HAA synthesis enzyme KMO suppressed tumor formation and tumor growth by increasing endogenous 3-HAA while adding exogenous 3-HAA also inhibited tumor growth. Notably, 3-HAA was lower in tumor cells due to the downregulation of its synthetic enzyme KMO/KYNU and/or upregulation of its catalytic enzyme HAAO. The mechanistic investigation demonstrated that 3-HAA induced dual-specificity phosphatase 6 (DUSP6) transcription. DUSP6 overexpression induced apoptosis of hepatocellular carcinoma (HCC) cells and suppressed the HCC growth in vitro and in vivo . DUSP6 knockdown abolished 3-HAA-induced apoptosis and restores tumor growth. Conclusions These findings demonstrate that 3-HAA metabolic pathway regulates HCC cell growth, suggesting it is a promising therapeutic candidate for HCC.

Objectives: Sorafenib is the only FDA-approved first-line target drug for HCC patients. However, sorafenib merely confers 3-5 months of survival benefit with less than 30% of HCC patients sensitive to sorafenib therapy. Thus, it's necessary to develop a sensitizer for hepatocellular carcinoma (HCC) to sorafenib. Methods: The principal component analysis, gene ontology, and KEGG analysis are utilized following RNA-sequencing. The mass spectrometry analysis following immunoprecipitation is performed to discover the phosphatase targets. Most importantly, both the cell line-derived xenograft (CDX) and the patient-derived xenograft (PDX) mouse model are used to determine the effect of 3-HAA on sorafenib-resistant HCC in vivo. Results: In nude mice carrying HCC xenograft, tumor growth is inhibited by sorafenib or 3-HAA alone. When used in combination, the treatment particularly prevents the xenograft from growing. Combined treatment also suppresses the growth of sorafenib-resistant (≥30mg/kg) PDXs. In a set of mechanistic experiments, we find enhanced AKT activation and decreased apoptotic cells in de novo and acquired sorafenib-resistant HCC cells and tissues. 3-HAA decreases AKT phosphorylation and increases the apoptosis of HCC in both cultured cells and mouse xenografts by upregulation of phosphatases PPP1R15A/DUSP6. PPP1R15A/PPP1α directly reduces Akt phosphorylation while DUSP6 decreases Akt activity through inhibiting PDK1. The AKT activator abolishes 3-HAA inhibition of HCC growth in vitro and in mice. Conclusion: This study demonstrates that 3-HAA sensitizes HCC cells to sorafenib by upregulation of phosphatases, suggesting it as a promising molecule for HCC therapy.