Cystatin B increases autophagic flux by sustaining proteolytic activity of cathepsin B and fuels glycolysis in pancreatic cancer: CSTB orchestrates autophagy and glycolysis in PDAC

Effects of CSTB on in vitro maturation of ovine oocytes

Cystatin B (CSTB) primarily acts as an intracellular cysteine cathepsin inhibitor and plays important biological functions in multiple tissues. This study aimed to investigate the expression of CSTB in ovine ovaries and its effect on the in vitro maturation of ovine oocytes. We cloned a 390 bp CSTB cDNA fragment, containing 297 bp coding sequence and encoding 98 amino acids. The amino acid sequence of the homologues of ovine CSTB is 72.45-98.98 % similar to other species. In addition, CSTB is highly expressed in the ovary and uterus of the reproductive system, specifically localized in granulosa cells and oocytes. Adding recombinant CSTB to in vitro maturation medium increased the maturation rate, cleavage rate and blastocyst rate of small follicle oocytes. Conversely, interfering with CSTB knockdown reduced the maturation rate and developmental potential of oocytes. Recombinant protein upregulated mitochondrial membrane potential, ATP, and autophagy protein LC3A/LC3B in oocytes while downregulated reactive oxygen species. In contrast, CSTB knockdown reversed these trends, resulting in significant downregulation of membrane potential, ATP, and LC3A/LC3B and upregulation of reactive oxygen species. In conclusion, CSTB is a critical functional molecule for the in vitro maturation of ovine oocytes. It regulates oocyte developmental potential by modulating reactive oxygen species (ROS), membrane potential and autophagy in ovine oocytes. These findings enhance the understanding of the role of CSTB in ovine oocyte maturation in vitro.

Machine Learning-Based Radiomics in Malignancy Prediction of Pancreatic Cystic Lesions: Evidence from Cyst Fluid Multi-Omics

The malignant potential of pancreatic cystic lesions (PCLs) varies dramatically, leading to difficulties when making clinical decisions. This study aimed to develop noninvasive clinical-radiomic models using preoperative CT images to predict the malignant potential of PCLs. It also investigates the biological mechanisms underlying these models. Patients from two retrospective and one prospective cohort, all undergoing surgical resection for PCLs, are divided into four datasets: training, internal test, external test, and prospective application sets. Eleven machine learning classifiers are employed to construct radiomic models based on selected features. Cyst fluid from the prospective cohort is collected for proteomic and lipidomic analysis. The radiomic models demonstrated high accuracy, with area under the receiver operating characteristic curves (AUCs) > 0.93 across the training (n = 262), internal test (n = 50), and external test (n = 50) sets. AUCs ranged from 0.92 to 0.96 for the prospective cohort (n = 34). Meanwhile, differentially-expressed proteins and lipid molecules, along with their associated signaling pathways, are identified between high and low groups of clinical-radiomic scores. This models can effectively and accurately predict the malignant potential of PCLs, with multi-omics evidence suggesting the biological mechanisms involving secretion function and lipid metabolism underlying clinical-radiomic models.

Preliminary Observations of a Substrate-Based Radiotracer Biosensor for In Vivo Positron Emission Tomography Imaging of Tumor Transmembrane Protease ST14

Imaging protease proteolysis with positron emission tomography (PET) has not been well documented in the literature, primarily due to the absence of suitable radiotracers. This study aims to develop a substrate-based radiotracer biosensor for ST14 protease to facilitate direct in vivo PET imaging of proteolysis. The design of the substrate-based radiotracer RQARK-DOTA-68Ga is characterized by the inclusion of an ST14 substrate RQAR moiety and a Lys-DOTA-68Ga moiety, linked via an ST14 cleavage site. The enzymatic cleavage of this radiotracer by ST14 protease was characterized in vitro, and the proteolysis of ST14 was further confirmed through in vivo PET imaging in tumors expressing ST14. RQARK-DOTA-68Ga was specifically cleaved by ST14 protease to yield Lys-DOTA-68Ga and RQAR moieties, whereas the d-isomer, rqark-DOTA-68Ga, was not susceptible to cleavage by ST14 protease. In vivo PET imaging demonstrated high tumor uptake of radioactive signal postinjection RQARK-DOTA-68Ga in ST14-expressing AsPC-1 xenografts, with optimal accumulation observed 1 h postinjection. In contrast, the d-isomer radiotracer, rqark-DOTA-68Ga, exhibited negligible tumor uptake, indicating a distinct preference for the substrate-based radiotracer in regions of ST14-mediated proteolysis. Radio-HPLC analysis following extraction from AsPC-1 tumors injected with RQARK-DOTA-68Ga identified a radioactive peak corresponding to Lys-DOTA-68Ga, confirming enzymatic cleavage and the generation of the anticipated radioactive product in the tumor tissue. Preliminary results indicate that a novel strategy for noninvasive in vivo positron emission tomography imaging of the transmembrane protease ST14 in tumors has been introduced through the development and application of a substrate-based radiotracer biosensor. The radiotracer RQARK-DOTA-68Ga, capable of producing imaging signals through structural changes triggered by substrate cleavage, has proven its ST14-targeting potency in both in vitro enzymatic assays and in vivo PET imaging.

Transcriptomic profiles of single-cell autophagy-related genes (ATGs) in lung diseases

Autophagy related genes (ATGs) play essential roles in maintaining cellular functions, although biological and pathological alterations of ATG phenotypes remain poorly understood. To address this knowledge gap, we utilized the single-cell sequencing technology to elucidate the transcriptomic atlas of ATGs in lung diseases, with a focus on lung epithelium and lymphocytes. This study conducted a comprehensive investigation into RNA profiles of ATGs in the lung tissues obtained from healthy subjects and patients with different lung diseases through single-cell RNA sequencing (scRNA-seq), including COVID-19 related acute lung damage, idiopathic pulmonary fibrosis (IPF), chronic obstructive pulmonary disease (COPD), systemic sclerosis (SSC), and lung adenocarcinoma (LUAD). Our findings revealed significant variations of ATGs expression across lung epithelial cell subsets, e.g., over-expression of MAPK8 in basal cells, ATG10 in club cells, and BCL2 in a goblet cell subset. The changes of autophagy-related pathways varied between lung epithelial and lymphocyte subsets. We identified the disease-associated changes in ATG expression, including significant alterations in BCL2, BCL2L1, PRKCD, and PRKCQ in inflammatory lung diseases (COPD and IPF), and MAP2K7, MAPK3, and RHEB in lung cancer (LUAD), as compared to normal lung tissues. Key ligand-receptor pairs (e.g., CD6-ALCAM, CD99-CD99) and signaling pathways (e.g., APP, CD74) might serve as biomarkers for lung diseases. To evaluate ATGs responses to external challenges, we examined ATGs expression in different epithelial cell lines exposed to cigarette smoking extract (CSE), lysophosphatidylcholine (lysoPC), lipopolysaccharide (LPS), and cholesterol at various doses and durations. Notable changes were observed in CFLAR, EIF2S1, PPP2CA, and PPP2CB in A549 and H1299 against CSE and LPS. The heterogeneity of ATGs expression was dependent on cell subsets, pathologic conditions, and challenges, as well as varied among cellular phenotypes, functions, and behaviors, and the severity of lung diseases. In conclusion, our data might provide new insights into the roles of ATGs in epithelial biology and pulmonary disease pathogenesis, with implications for disease progression and prognosis.

Cystatin B Promotes the Proliferation, Migration, and Invasion of Intrahepatic Cholangiocarcinoma

Background and Aims: Cystatin B (CSTB) has been demonstrated to play a significant role in the pathogenesis of a number of diseases, including the evolution and progression of multiple cancers. Nevertheless, the function of CSTB in intrahepatic cholangiocarcinoma (iCCA) is yet to be fully elucidated. Methods: By analyzing transcriptome sequencing data from the FU-iCCA cohort, the iCCA-27 cohort, and three public databases, we identified genes associated with iCCA prognosis and selected CSTB as the subject of our study. The expression of CSTB was examined between tumor tissues and adjacent normal tissues obtained from iCCA patients via Western blot analysis. The clinical significance of CSTB was analyzed through immunohistochemical staining of a tissue microarray. Subsequently, the biological effects of CSTB overexpression or knockdown on iCCA cells were evaluated in vitro and in vivo. Results: CSTB expression was markedly elevated in the CCA pathological tissues in comparison to the corresponding adjacent normal tissues. A correlation was identified between higher CSTB expression and poorer patient prognosis in the analysis of 176 iCCA patients. It is noteworthy that overexpression or knockdown experiments demonstrated that CSTB plays a role in the proliferation, migration, and invasion of cells. In subcutaneous tumor models in nude mice, the knockdown of CSTB resulted in smaller tumors in terms of size and weight, and a slower growth rate. Conclusions: CSTB plays a significant function in the regulation of iCCA progression and may serve as a promising biomarker for iCCA.

Specific BCG-related gene expression levels correlate with immune cell infiltration and prognosis in melanoma

Melanoma, caused by malignant melanocytes, is known for its invasiveness and poor prognosis. Therapies are often ineffective due to their heterogeneity and resistance. Bacillus Calmette-Guérin (BCG), primarily a tuberculosis vaccine, shows potential in treating melanoma by activating immune responses. In this study, data from The Cancer Genome Atlas and the National Center for Biotechnology Information Gene Expression Omnibus database were utilized to determine pivotal DEGs such as DSC2, CXCR1, BOK, and CSTB, which are significantly upregulated in BCG-treated blood samples and are strongly associated with the prognosis of melanoma. We employ tools like edgeR and ggplot2 for functional and pathway analysis and develop a prognostic model using LASSO Cox regression analysis to predict patient survival. A notable finding is the correlation between BCG-related genes and immune cell infiltration in melanoma, highlighting the potential of these genes as both biomarkers and therapeutic targets. Additionally, the study examines genetic alterations in these genes and their impact on the disease. This study highlights the necessity of further exploring BCG-related genes for insights into melanoma pathogenesis and treatment enhancement, suggesting that BCG's role in immune activation could offer novel therapeutic avenues in cancer treatment.

Cathepsins and cancer risk: a Mendelian randomization study

Background

Previous observational epidemiological studies reported an association between cathepsins and cancer, however, a causal relationship is uncertain. This study evaluated the causal relationship between cathepsins and cancer using Mendelian randomization (MR) analysis.

Methods

We used publicly available genome-wide association study (GWAS) data for bidirectional MR analysis. Inverse variance weighting (IVW) was used as the primary MR method of MR analysis.

Results

After correction for the False Discovery Rate (FDR), two cathepsins were found to be significantly associated with cancer risk: cathepsin H (CTSH) levels increased the risk of lung cancer (OR = 1.070, 95% CI = 1.027-1.114, P = 0.001, PFDR = 0.009), and CTSH levels decreased the risk of basal cell carcinoma (OR = 0.947, 95% CI = 0.919-0.975, P = 0.0002, P FDR = 0.002). In addition, there was no statistically significant effect of the 20 cancers on the nine cathepsins. Some unadjusted low P-value phenotypes are worth mentioning, including a positive correlation between cathepsin O (CTSO) and breast cancer (OR = 1.012, 95% CI = 1.001-1.025, P = 0.041), cathepsin S (CTSS) and pharyngeal cancer (OR = 1.017, 95% CI = 1.001-1.034, P = 0.043), and CTSS and endometrial cancer (OR = 1.055, 95% CI = 1.012-1.101, P = 0.012); and there was a negative correlation between cathepsin Z and ovarian cancer (CTSZ) (OR = 0.970, 95% CI = 0.949-0.991, P = 0.006), CTSS and prostate cancer (OR = 0.947, 95% CI = 0.902-0.944, P = 0.028), and cathepsin E (CTSE) and pancreatic cancer (OR = 0.963, 95% CI = 0.938-0.990, P = 0.006).

Conclusion

Our MR analyses showed a causal relationship between cathepsins and cancers and may help provide new insights for further mechanistic and clinical studies of cathepsin-mediated cancer.

Fundamental insights and molecular interactions in pancreatic cancer: Pathways to therapeutic approaches

The gastrointestinal tract can be affected by a number of diseases that pancreatic cancer (PC) is a malignant manifestation of them. The prognosis of PC patients is unfavorable and because of their diagnosis at advanced stage, the treatment of this tumor is problematic. Owing to low survival rate, there is much interest towards understanding the molecular profile of PC in an attempt in developing more effective therapeutics. The conventional therapeutics for PC include surgery, chemotherapy and radiotherapy as well as emerging immunotherapy. However, PC is still incurable and more effort should be performed. The molecular landscape of PC is an underlying factor involved in increase in progression of tumor cells. In the presence review, the newest advances in understanding the molecular and biological events in PC are discussed. The dysregulation of molecular pathways including AMPK, MAPK, STAT3, Wnt/β-catenin and non-coding RNA transcripts has been suggested as a factor in development of tumorigenesis in PC. Moreover, cell death mechanisms such as apoptosis, autophagy, ferroptosis and necroptosis demonstrate abnormal levels. The EMT and glycolysis in PC cells enhance to ensure their metastasis and proliferation. Furthermore, such abnormal changes have been used to develop corresponding pharmacological and nanotechnological therapeutics for PC.

A bioinformatics analysis, pre-clinical and clinical conception of autophagy in pancreatic cancer: Complexity and simplicity in crosstalk

Pancreatic cancer (PC) is a serious gastrointestinal tract disease for which the 5-year survival rate is less than 10%, even in developed countries such as the USA. The genomic profile alterations and dysregulated biological mechanisms commonly occur in PC. Macroautophagy/autophagy is a cell death process that is maintained at a basal level in physiological conditions, whereas its level often changes during tumorigenesis. The function of autophagy in human cancers is dual and can be oncogenic and onco-suppressor. Autophagy is a potent controller of tumorigenesis in PC. The supportive autophagy in PC escalates the growth rate of PC cells and its suppression can mediate cell death. Autophagy also determines the metastasis of PC cells, and it can control the EMT in affecting migration. Moreover, starvation and hypoxia can stimulate glycolysis, and glycolysis induction can be mediated by autophagy in enhancing tumorigenesis in PC. Furthermore, protective autophagy stimulates drug resistance and gemcitabine resistance in PC cells, and its inhibition can enhance radiosensitivity. Autophagy can degrade MHC-I to mediate immune evasion and also regulates polarization of macrophages in the tumor microenvironment. Modulation of autophagy activity is provided by silibinin, ursolic acid, chrysin and huaier in the treatment of PC. Non-coding RNAs are also controllers of autophagy in PC and its inhibition can improve therapy response in patients. Moreover, mitophagy shows dysregulation in PC, which can enhance the proliferation of PC cells. Therefore, a bioinformatics analysis demonstrates the dysregulation of autophagy-related proteins and genes in PC as biomarkers.

Cystatin B increases autophagic flux by sustaining proteolytic activity of cathepsin B and fuels glycolysis in pancreatic cancer: CSTB orchestrates autophagy and glycolysis in PDAC

BACKGROUND

Both autophagy and glycolysis are essential for pancreatic ductal adenocarcinoma (PDAC) survival due to desmoplasia. We investigated whether targeting a hub gene which participates in both processes could be an efficient strategy for PDAC treatment.

METHODS

The expression pattern of glycolysis signatures (GS) and autophagy signatures (AS) and their correlation with cystatin B (CSTB) in PDAC were analysed. It was discovered how CSTB affected the growth, glycolysis, and autophagy of PDAC cells. We assessed competitive binding to cathepsin B (CTSB) between CSTB and cystatin C (CSTC) via immunoprecipitation (IP) and immunofluorescence (IF). Chromatin immunoprecipitation quantitative polymerase chain reaction (ChIP-qPCR) and luciferase reporter gene assays were used to unveil the mechanism underlying CSTB upregulation. The expression pattern of CSTB was examined in clinical samples and KrasG12D/+, Trp53R172H/+, Pdx1-Cre (KPC) mice.

RESULTS

GS and AS were enriched and closely associated in PDAC tissues. CSTB increased autophagic flux and provided substrates for glycolysis. CSTB knockdown attenuated the proliferation of PDAC cells and patient-derived xenografts. The liquid chromatography-tandem mass spectrometry assay indicated CSTB interacted with CTSB and contributed to the proteolytic activity of CTSB in lysosomes. IF and IP assays demonstrated that CSTB competed with CSTC to bind to CTSB. Mutation of the key sites of CSTB abolished the interaction between CSTB and CTSB. CSTB was highly expressed in PDAC due to H3K27acetylation and SP1 expression. High expression of CSTB in PDAC was observed in tissue microarray and patients' serum samples.

CONCLUSIONS

Our work demonstrated the tumorigenic roles of autophagy and glycolysis in PDAC. CSTB is a key role in orchestrating these processes to ensure energy supply of PDAC cells.