PYCR1 promotes liver cancer cell growth and metastasis by regulating IRS1 expression through lactylation modification.

BACKGROUND: Liver cancer (LC) is among the deadliest cancers worldwide, with existing treatments showing limited efficacy. This study aimed to elucidate the role and underlying mechanisms of pyrroline-5-carboxylate reductase 1 (PYCR1) as a potential therapeutic target in LC. METHODS: Immunohistochemistry and Western blot were used to analyse the expression of PYCR1 in LC cells and tissues. EdU assays, colony-forming assays, scratch wound healing assays, Transwell assays, nude mouse xenograft models and nude mouse lung metastasis models were used to detect the growth and metastasis abilities of LC cells. Transcriptome sequencing was used to search for downstream target genes regulated by PYCR1, and metabolomics was used to identify the downstream metabolites regulated by PYCR1. ChIP assays were used to analyse the enrichment of H3K18 lactylation in the IRS1 promoter region. RESULTS: We found that the expression of PYCR1 was significantly increased in HCC and that this high expression was associated with poor prognosis in HCC patients. Knockout or inhibition of PYCR1 inhibited HCC cell proliferation, migration and invasion both in vivo and in vitro. In addition, we revealed that knocking out or inhibiting PYCR1 could inhibit glycolysis in HCC cells and reduce H3K18 lactylation of the IRS1 histone, thereby inhibiting IRS1 expression. CONCLUSIONS: Our findings identify PYCR1 as a pivotal regulator of LC progression that influences tumour cell metabolism and gene expression. By demonstrating the potential of targeting PYCR1 to inhibit LC cell proliferation and metastasis, this study identified PYCR1 as a promising therapeutic target for LC. HIGHLIGHTS: Pyrroline-5-carboxylate reductase 1 (PYCR1) promotes the proliferation and metastasis of liver cancer (LC) cells. The expression of PYCR1 in LC is regulated by DNA methylation. Knocking down or inhibiting PYCR1 inhibits glycolysis as well as the PI3K/AKT/mTOR and MAPK/ERK pathways in LC cells. PYCR1 regulates the transcriptional activity of IRS1 by affecting H3K18 lactylation in its promoter region.

Confirming the enzymatic activity and neurodevelopmental trajectory of PYCR1 mutation in one child with autosomal-recessive cutis laxa type 2.

Autosomal-recessive cutis laxa type 2 (ARCL2) is a rare genetic disorder caused by pyrroline-5-carboxylate reductase 1 (PYCR1) mutations and characterized by loose and sagging skin, typical facial features, intrauterine growth retardation, and developmental delay. To study the effect of PYCR1 mutations on protein function and clinical features, we identified a homozygous missense mutation c.559G > A (p.Ala187Thr) in PYCR1 in a Chinese child with typical clinical features, especially severe developmental delays. The three-dimensional (3D) model showed the modification of the hydrogen bonds produce a misfolding in the mutant PYCR1 protein. Mutagenesis and enzyme assay study revealed decreased activity of the mutant protein in vitro, indicating that this mutation impairs PYCR1 function. Our findings confirmed abnormal enzymatic activity and neurodevelopmental trajectory of this PYCR1 mutation.

ITPKA phosphorylates PYCR1 and promotes the progression of glioma.

Glioma is one of the prevalent malignancies, and identifying therapeutic targets for glioma is highly important. Findings of current study revealed that inositol-trisphosphate 3-kinase A (ITPKA) was found abnormally over expressed and thereby exhibited poor prognosis with glioma. Extensive academic research has meticulously elucidated ITPKA's pivotal role in enhancing glioma cell proliferation and invasion, highlighting its significance in oncogenic pathways and cellular dynamics specific to aggressive brain tumors. Inhibiting the ITPKA has wide scope to reduce the tumorigenicity in gliomas in vivo. We also noticed that ITPKA interacts with PYCR1 and phosphorylates serine 29 of PYCR1. Phosphorylation of serine 29 inhibits the E3 ligase Stub1-mediated ubiquitination of PYCR1, thereby stabilizing its protein level. Based on our findings, it was determined that the phosphorylation of serine 29 in PYCR1 by ITPKA enhances the stability of the phosphorylated PYCR1 protein. This, in turn, involved significantly in oncogenic function of ITPKA in glioblastoma. Consequently, ITPKA holds promise as a potential target in prospective glioma therapy.

BHLHE41 inhibits bladder cancer progression via regulation of PYCR1 stability and thus inactivating PI3K/AKT signaling pathway.

BACKGROUND: The basic helix-loop-helix family member e41 (BHLHE41) is frequently dysregulated in tumors and plays a crucial role in malignant progression of various cancers. Nevertheless, its specific function and underlying mechanism in bladder cancer (BCa) remain largely unexplored. METHODS: The expression levels of BHLHE41 in BCa tissues and cells were examined by qRT-PCR and western blot assays. BCa cells stably knocking down or overexpressing BHLHE41 were constructed through lentivirus infection. The changes of cell proliferation, cell cycle distribution, migration, and invasion were detected by CCK-8, flow cytometry, wound healing, transwell invasion assays, respectively. The expression levels of related proteins were detected by western blot assay. The interaction between BHLHE41 and PYCR1 was explored by co-immunoprecipitation analysis. RESULTS: In this study, we found that BHLHE41 was lowly expressed in bladder cancer tissues and cell lines, and lower expression of BHLHE41 was associated with poor overall survival in bladder cancer patients. Functionally, by manipulating the expression of BHLHE41, we demonstrated that overexpression of BHLHE41 significantly retarded cell proliferation, migration, invasion, and induced cell cycle arrest in bladder cancer through various in vitro and in vivo experiments, while silence of BHLHE41 caused the opposite effect. Mechanistically, we showed that BHLHE41 directly interacted with PYCR1, decreased its stability and resulted in the ubiquitination and degradation of PYCR1, thus inactivating PI3K/AKT signaling pathway. Rescue experiments showed that the effects induced by BHLHE41 overexpression could be attenuated by further upregulating PYCR1. CONCLUSION: BHLHE41 might be a useful prognostic biomarker and a tumor suppressor in bladder cancer. The BHLHE41/PYCR1/PI3K/AKT axis might be a potential therapeutic target for bladder cancer intervention.

Loss of mitochondrial pyruvate carrier 1 supports proline-dependent proliferation and collagen biosynthesis in ovarian cancer.

The pyruvate transporter MPC1 (mitochondrial pyruvate carrier 1) acts as a tumour-suppressor, loss of which correlates with a pro-tumorigenic phenotype and poor survival in several tumour types. In high-grade serous ovarian cancers (HGSOC), patients display copy number loss of MPC1 in around 78% of cases and reduced MPC1 mRNA expression. To explore the metabolic effect of reduced expression, we demonstrate that depleting MPC1 in HGSOC cell lines drives expression of key proline biosynthetic genes; PYCR1, PYCR2 and PYCR3, and biosynthesis of proline. We show that altered proline metabolism underpins cancer cell proliferation, reactive oxygen species (ROS) production, and type I and type VI collagen formation in ovarian cancer cells. Furthermore, exploring The Cancer Genome Atlas, we discovered the PYCR3 isozyme to be highly expressed in a third of HGSOC patients, which was associated with more aggressive disease and diagnosis at a younger age. Taken together, our study highlights that targeting proline metabolism is a potential therapeutic avenue for the treatment of HGSOC.

Effects of PYCR1 on prognosis and immunotherapy plus tyrosine kinase inhibition responsiveness in metastatic renal cell carcinoma patients.

BACKGROUND: Immunotherapy plus tyrosine kinase inhibitor (IO-TKI) has become the first-line management for metastatic renal cell carcinoma (RCC), despite the absence of biomarkers. Recently, pyrroline-5-carboxylate reductase 1 (PYCR1) and proline metabolism have been reported regulatory roles in the anti-tumor response. METHODS: There were three cohorts enrolled: two from our institution (ZS-MRCC and ZS-HRRCC) and one from a clinical trial (JAVELIN-101). The PYCR1expression in each sample was evaluated by RNA sequencing. Flow cytometry and immunohistochemistry were performed to assess immune infiltration. Single-cell RNA-seq (scRNA-seq) data was used for cluster analysis of T cells and macrophages. Primary endpoints were set as response and progression-free survival (PFS). RESULTS: Patients in the low-PYCR1 group had greater objective response rate (52.2% vs 18.2%) and longer PFS in both cohorts (ZS-MRCC cohort, P=0.01, HR=2.80; JAVELIN-101 cohort, P<0.001, HR=1.85). In responders, PYCR1 expression was decreased (P<0.05). In the high PYCR1 group, CD8+ T cells exhibited an exhausted phenotype with decreased GZMB (Spearman's ρ=-0.36, P=0.02). scRNA-seq revealed tissue-resident memory T (Trm) (P<0.05) and tissue-resident macrophage (P<0.01) were decreased in samples with high PYCR1 expression. A machine learning score was further built by random forest, involving PYCR1 and Trm markers. Only in the subgroup with the lower RFscore did IO+TKI show a favorable outcome, compared to TKI monotherapy. CONCLUSIONS: Immunosuppression and IO+TKI resistance were correlated with high PYCR1 expression. T cell exhaustion and dysfunction were also related with the expression of PYCR1. PYCR1 has the potential to be employed as a biomarker to discriminate between IO+TKI and TKI monotherapy as the optimal patient treatment strategy.

Antisense lncRNA-RP11-498C9.13 promotes bladder cancer progression by enhancing reactive oxygen species-induced mitophagy.

BACKGROUND: Urinary system's most prevalent malignant tumor is bladder cancer. The enzyme pyrroline-5-carboxylate reductase 1 (PYCR1) has pro-tumorigenic characteristics. In the present study, the upstream and downstream regulatory mechanisms of PYCR1 in bladder cancer were investigated. METHODS: The relationship between the expression of PYCR1 in bladder cancer and its prognosis was analyzed using a bioinformatics technique. Plasmid transfection and small interfering RNA were utilized to overexpress and silence genes, respectively. Utilizing MTT, colony formation, EdU, and transwell assays, the proliferation and invasiveness of bladder cancer cells were evaluated. Employing an RNA pull-down experiment and RNA immunoprecipitation, the relationship between RNAs was analyzed. Fluorescence in situ hybridization, immunohistochemistry, and western blotting were used to detect protein expression and localization. Flow cytometry was used to identify reactive species (ROS) expression in cells. Mitophagy was detected using immunofluorescence. RESULTS: PYCR1 was highly expressed in bladder cancer tissue and was related with a poor prognosis for the patient. By binding to PYCR1, the antisense RNA lncRNA-RP11-498C9.13 prevented the degradation of PYCR1 and promoted its production. Down-regulation of lncRNA-RP11-498C9.13 and PYCR1 inhibited the proliferation and invasiveness of bladder cancer cells and decreased tumorigenesis. In addition, it was found that the lncRNA-RP11-498C9.13/PYCR1 axis promoted ROS generation and induced mitophagy in bladder cancer cells. CONCLUSIONS: We demonstrated that lncRNA-RP11-498C9.13 promoted bladder cancer tumorigenesis by stabilizing the mRNA of PYCR1 and promoted ROS-induced mitophagy. The lncRNA-RP11-498C9.13/PYCR1/mitophagy axis was anticipated to be a significant therapeutic target for bladder cancer.

Integrated analysis of the roles of oxidative stress related genes and prognostic value in clear cell renal cell carcinoma.

BACKGROUND: Patients with clear cell renal cell carcinoma (ccRCC), which is the most commonly diagnosed subtype of renal cell carcinoma, are at risk of tumor metastasis and recrudescence. Previous research has shown that oxidative stress can induce tumorigenesis in many cancers and can be a target of cancer treatment. Despite these findings, little progress has been made understanding in the association of oxidative stress-related genes (OSRGs) with ccRCC. METHODS: In vitro experiments were conducted with MTT survival assays, qRT‒PCR, apoptosis assays, cell cycle assays, ROS assays, and IHC staining. RESULTS: In our study, 12 differentially expressed oxidative stress-related genes (DEOSGs) and related transcription factors (TFs) that are relevant to overall survival (OS) were screened, and their mutual regulatory networks were constructed with data from the TCGA database. Moreover, we constructed a risk model of these OSRGs and performed clinical prognostic analysis and validation. Next, we performed protein-protein interaction (PPI) network analysis and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of MELK, PYCR1, and PML. A tissue microarray also verified the high expression of MELK and PYCR1 in ccRCC. Finally, in vitro cellular experiments demonstrated that knockdown of MELK or PYCR1 significantly inhibited ccRCC cell proliferation by causing cell apoptosis and inducing cell cycle arrest in the G1 phase. Intracellular ROS levels were elevated after these two genes were knocked down. CONCLUSION: Our results revealed the potential DEORGs to be used in ccRCC prognostic prediction and identified two biomarkers, named PYCR1 and MELK, which regulated the proliferation of ccRCC cells by affecting ROS levels. Furthermore, PYCR1 and MELK could be promising targets for predicting the progression and prognosis of ccRCC, thereby serving as new targets for medical treatments.

PYCR1 promotes the malignant progression of lung cancer through the JAK-STAT3 signaling pathway via PRODH-dependent glutamine synthesize.

BACKGROUND: Lung cancer is a serious threat to human life. It is of great significance to elucidate the pathogenesis of lung cancer and search for new markers. This study evaluate the clinical value of pyrroline-5-carboxylate reductase 1 (PYCR1) and explore its role and mechanisms in the malignant progression of lung cancer. METHODS: PYCR1 expression and its relationship with prognosis were analyzed using a bioinformatics database. Enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry were utilized to examine the expression of PYCR1 in lung cancer tissues and peripheral blood. PYCR1-overexpressing lung cancer cells were constructed, then the cell proliferative, migration, and invasion ability was examined by the MTT and Transwell assays. siRNA against PRODH and STAT3 inhibitor sttatic was used to further elucidate the underlying mechanisms. Luciferase and CHIP assays were carried out for validate the how PYCR1 regulated PD-L1 expression via STAT3. Xenograft experiment was performed to determine the role of PYCR1 in vivo. RESULTS: Database analysis showed that PYCR1 expression was significantly increased in lung cancer tissues, and its high expression predicted poor prognosis. Lung cancer tissue and peripheral blood of patients showed obviously increased PYCR1 expression, and the sensitivity and specificity of serum PYCR1 in the diagnosis of lung cancer were 75.7% and 60%, respectively. PYCR1 overexpression enhanced the proliferative, migration, and invasion abilities of lung cancer cells. Both PRODH silence and stattic effectively attenuated the function of PYCR1. Animal experiment and IHC data indicated that PYCR1 could activated STAT3 phosphorylation and PD-L1, as well as suppressed T cell infiltration in lung cancer. Finally, we also validated that PYCR1 promoted PD-L1 transcription by elevating STAT3 binding to the gene promoter. CONCLUSION: PYCR1 has certain value in the diagnosis and prognosis of lung cancer. Moreover, through regulating JAK-STAT3 signaling pathway, PYCR1 significantly participated in process of lung cancer progression via the metabolism link between proline and glutamine, indicating that PYCR1 might be also a novel therapeutic target.

Progeroid syndrome of De Barsy - a case report and review of ophthalmic literature.

BACKGROUND: This report describes a very rare case of progeroid syndrome of De Barsy (Cutis laxa-corneal clouding syndrome). MATERIALS AND METHODS: A 2 year-old child presented to the pediatric ophthalmology outpatients with bilateral congenital corneal opacification along with dysmorphic facial features, including loose wrinkled skin, progeroid appearance, delayed milestones, short stature, multiple hyper-extensible joints, muscular hypotonia, pectus excavatum and congenital dislocation of the hip joint. The child underwent a detailed ophthalmic work up and systemic evaluation by a clinical geneticist. RESULTS: Ophthalmic management in the form of bilateral sequential penetrating keratoplasties and a left eye trabeculectomy for medically uncontrolled angle-closure glaucoma was performed. Visual rehabilitation with glasses and amblyopia therapy is ongoing. Histopathology of the corneal button revealed loss of the bowman's layer which was replaced by a fibrous pannus while the stroma showed loss of stromal lamellar architecture with anterior and mid stroma showing vascularization. Genetic testing confirmed a mutation in the PYCR1 gene for a homozygous autosomal recessive cutis laxa type IIB. CONCLUSIONS: Although rare, De Barsy syndrome is an important cause of corneal opacification at birth with multiple systemic abnormalities that requires intervention.

LINC00511 aggravates the malignancy of lung adenocarcinoma through sponging microRNA miR-4739 to regulate pyrroline-5-carboxylate reductase 1 expression.

BACKGROUND: Long non-coding RNA LINC00511 is known to exacerbate lung adenocarcinoma (LUAD) progression. However, the specific mechanism by which LINC00511 affects LUAD progression has not been investigated as yet, and we aimed to elucidate the same in the present study. METHODS: The expression levels of LINC00511, microRNA miR-4739, and pyrroline-5-carboxylate reductase 1 (PYCR1) were determined by quantitative reverse transcription PCR and Western blotting. The Cell Counting Kit-8 and bromodeoxyuridine assays were used to evaluate cell proliferation. Apoptosis was evaluated by flow cytometry, and Bax and Bcl-2 protein levels were determined by western blotting. Cell migration was assessed using transwell assay. The interaction between LINC00511, miR-4739, and PYCR1 was analyzed using luciferase, RNA immunoprecipitation, and RNA pull-down assays. RESULTS: The expression levels of LINC00511 and PYCR1 in LUAD were downregulated, whereas that of miR-4739 was upregulated. Functional studies showed that knockdown of LINC00511 or PYCR1 suppressed the proliferation and migration of LUAD cells, and promoted apoptosis. On the contrary, knockdown of miR-4739 had tumor-promoting effects. Mechanistically, LINC00511 prevented the miR-4739 led inhibition of PYCR1, resulting in PYCR1 overexpression. CONCLUSION: This study demonstrates for the first time that LINC00511 aggravates the malignancy of LUAD by sponging miR-4739 to upregulate PYCR1 expression.

Omics profiling identifies the regulatory functions of the MAPK/ERK pathway in nephron progenitor metabolism.

Nephron endowment is defined by fetal kidney growth and crucially dictates renal health in adults. Defects in the molecular regulation of nephron progenitors contribute to only a fraction of reduced nephron mass cases, suggesting alternative causative mechanisms. The importance of MAPK/ERK activation in nephron progenitor maintenance has been previously demonstrated, and here, we characterized the metabolic consequences of MAPK/ERK deficiency. Liquid chromatography/mass spectrometry-based metabolomics profiling identified 42 reduced metabolites, of which 26 were supported by in vivo transcriptional changes in MAPK/ERK-deficient nephron progenitors. Among these, mitochondria, ribosome and amino acid metabolism, together with diminished pyruvate and proline metabolism, were the most affected pathways. In vitro cultures of mouse kidneys demonstrated a dosage-specific function for pyruvate in controlling the shape of the ureteric bud tip, a regulatory niche for nephron progenitors. In vivo disruption of proline metabolism caused premature nephron progenitor exhaustion through their accelerated differentiation in pyrroline-5-carboxylate reductases 1 (Pycr1) and 2 (Pycr2) double-knockout kidneys. Pycr1/Pycr2-deficient progenitors showed normal cell survival, indicating no changes in cellular stress. Our results suggest that MAPK/ERK-dependent metabolism functionally participates in nephron progenitor maintenance by monitoring pyruvate and proline biogenesis in developing kidneys.

The role of PYCR1 in inhibiting 5-fluorouracil-induced ferroptosis and apoptosis through SLC25A10 in colorectal cancer.

Although PYCR1 is a well-recognized oncogenic gene for malignant tumors, the causal relationship of its expression with malignant growth and cytotoxic chemotherapeutics remains unclear. Therefore, this study aimed to clarify the role of PYCR1 and its interaction with SLC25A10 in a chemotherapeutic agent 5-fluorouracil (5-FU)'s toxicity to colorectal cancer cells. PYCR1 and SLC25A10 expressions were detected in The Cancer Genome Atlas database and colon adenocarcinoma (COAD) clinical samples. PYCR1 upregulation was associated with SLC25A10 expression and poor prognosis, and its high expression indicated decreased survival rates in patients with COAD. PYCR1 overexpression inhibited lipid reactive oxygen species production and promoted SLC25A10 expression in colorectal cancer cells. PYCR1 silencing enhanced the antitumor effects of 5-FU. Ferroptosis inhibitor deferoxamine suppressed the antitumor effects of PYCR1 silencing, whereas ferroptosis inducer erastin inhibited the protumor effects of PYCR1 overexpression. SLC25A10 overexpression reversed the antitumor effects of PYCR1 silencing in vitro and inhibited the antitumor effects of erastin in vivo. Therefore, PYCR1 is an oncogenic gene that promotes colorectal tumor growth and desensitizes colorectal cancer cells to 5-FU cytotoxicity by preventing apoptosis and ferroptosis.

Survival and clinicopathological significance of PYCR1 expression in cancer: A meta-analysis.

Background: Proline metabolism is closely related to the occurrence and development of cancer. Δ1-Pyrroline-5-carboxylate reductase (PYCR) is the last enzyme in proline biosynthesis. As one of the enzyme types, PYCR1 takes part in the whole process of the growth, invasion, and drug resistance of cancer cells. This study investigated PYCR1 expressions in cancers together with their relationship to clinical prognosis. Methods: A thorough database search was performed in PubMed, EMBASE, and Cochrane Library. RevMan5.3 software was used for the statistical analysis. Results: Eight articles were selected, and 728 cancer patients were enrolled. The cancer types include lung, stomach, pancreatic ductal adenocarcinoma, hepatocellular carcinoma, and renal cell carcinoma. The meta-analysis results showed that the expression of PYCR1 was higher in the clinical stage III-IV group than that in the clinical stage I-II group (OR = 1.67, 95%CI: 1.03-2.71), higher in the lymph node metastasis group than in the non-lymph node metastasis group (OR = 1.57, 95%CI: 1.06-2.33), and higher in the distant metastasis group than in the non-distant metastasis group (OR = 3.46, 95%CI: 1.64-7.29). However, there was no statistical difference in PYCR1 expression between different tumor sizes (OR = 1.50, 95%CI: 0.89-2.53) and degrees of differentiation (OR = 0.82, 95%CI: 0.54-1.24). Conclusion: PYCR1 had a high expression in various cancers and was associated with cancer volume and metastasis. The higher the PYCR1 expression was, the poorer the cancer prognosis was. The molecular events and biological processes mediated by PYCR1 might be the underlying mechanisms of metastasis.

PYCR1 regulates glutamine metabolism to construct an immunosuppressive microenvironment for the progression of clear cell renal cell carcinoma.

Metabolic reprogramming is critical for the setup of the tumor microenvironment (TME). Glutamine has slipped into the focus of research of cancer metabolism, but its role in clear cell renal cell carcinoma (ccRCC) remains vague. Our study aimed to investigate the regulatory mechanism of glutamine in ccRCC and its prognostic value. Gene expression profiles and clinical data of ccRCC patients were obtained from The Cancer Genome Atlas database (TCGA) and Gene Expression Omnibus (GEO) database. Kaplan-Meier survival analysis was used for survival analysis. Consensus clustering was used to extract differentially expressed genes (DEGs) related to glutamine metabolism. Functional analyses, including gene set variation analysis (GSVA) and gene set enrichment analysis (GSEA), were conducted to elucidate the functions and pathways involved in these DEGs. The single-sample GSEA and Estimation of Stromal and Immune cells in Malignant Tumor tissues using Expression data (ESTIMATE) methods were applied to estimate the immune infiltration in the TMEs of two clusters. The univariate regression and the least absolute shrinkage and selection operator (LASSO) Cox regression were used to construct a prognostic signature. R software was utilized to analyze the expression levels and prognostic values of genes in ccRCC. A total of 19 glutamine metabolic genes (GMGs) were screened out for differential expression analysis of normal and ccRCC tissues. Based on survival-related GMGs, two glutamine metabolic clusters with different clinical and transcriptomic characteristics were identified. Patients in cluster B exhibited worse survivals, higher immune infiltration scores, more significant immunosuppressive cell infiltration, higher expression levels of immune checkpoints, and more enriched oncogenic pathways. Glutamine metabolic index (GMI) was constructed according to the GMGs and survival data. In addition, the expression levels of GMGs were associated with immune cell infiltration and immune checkpoints in the TME of ccRCC. Among the GMGs, PYCR1 was the most powerful regulator of immune TME. Our analysis revealed higher-level glutamine metabolism in ccRCC patients with a worse prognosis. The GMI could predict the prognosis of ccRCC patients with a high accuracy. GMGs, such as PYCR1, may be exploited to design novel immunotherapies for ccRCC.

Circ_0000705 facilitates proline metabolism of esophageal squamous cell carcinoma cells by targeting miR-621/PYCR1 axis.

CircRNAs have been found to play crucial roles in the metabolism and progression of cancers, but their roles and mechanisms in esophageal squamous cell carcinoma (ESCC) have not been fully elucidated. This work is aimed to explore the role and mechanism of hsa_circ_0000705 (circ_0000705) in ESCC. Circ_0000705 expression was up-regulated in ESCC tissues and cell lines, and high circ_0000705 expression was correlated with poor survival. Circ_0000705 facilitated cell proliferation, invasion, migration and proline metabolism of ESCC cells. The inhibitory effects of circ_0000705 knockdown on cell invasion, migration and proline metabolism were partly rescued by miR-621 inhibition or PYCR1 over-expression. Furthermore, circ_0000705 expression is negatively correlated with miR-621 expression, and positively correlated with PYCR1 in ESCC tissues. Mechanistically, circ_0000705 acted as a ceRNA by sponging miR-621, thereby facilitating PYCR1 expression in ESCC cells. In conclusion, circ_0000705 promoted proline metabolism and malignant progression of ESCC by regulating the miR­621/PYCR1 axis.

Epigenetic modification facilitates proline synthase PYCR1 aberrant expression in gastric cancer.

BACKGROUND & AIMS: Pyrroline-5-carboxylate reductase 1 (PYCR1) upregulation contributes to the progression of gastric cancer (GC) and indicates poor survival. However, PYCR1 expression profile in GC subtypes and the mechanism behind its upregulation are not well-studied. METHODS: PYCR1 expression profiles in GC subtypes and different stages of gastric carcinogenesis were assessed in different GC cohorts. Genetic alterations and epigenetic modulation in PYCR1 regulation were further investigated using bioinformatics analysis and in vitro experiments. RESULTS: PYCR1 expression was significantly higher in intestinal-type GC and associated molecular subtypes in TCGA and ACRG GC cohorts. During the cascade of intestinal-type GC, PYCR1 was continuously increased from normal gastric tissues through to atrophic gastritis, to intraepithelial neoplasia, and to GC. Copy number alterations in PYCR1 were associated with PYCR1 transcript expression. One CpG island was observed in PYCR1 promoter region, and the hypomethylation occurred at this region could contribute to PYCR1 transcriptional activation in GC. Besides, H3K27ac combination was found in PYCR1 promoter, and acetyltransferase p300 induced H3K27ac could promote PYCR1 expression in GC. CONCLUSIONS: PYCR1 expression varies across GC subtypes, with intestinal-type GC and associated molecular subtypes having the highest expression. Hypomethylation at CpG sites and p300-induced H3K27ac modification within PYCR1 promoter could contribute to maintaining PYCR1 overexpression in GC. These results provide us with a new insight into epigenetic modulation in mitochondrial proline metabolism.

miR-150-5p inhibits nasopharyngeal cancer genesis by suppressing PYCR1.

BACKGROUND: Nasopharyngeal cancer (NPC) is a rare cancer type with a low five-year survival rate. Dysregulation of PYCR1 and miR-150-5p has been involved in the development of various cancers. However, the molecular mechanism of the miR-150-5p-PYCR1 axis in NPC remains unclear. METHODS: The expressions of miR-150-5p and PYCR1 in NPC tissues and cells were measured by RT-qPCR. The luciferase assay and RNA pull-down assay were used to confirm the interaction between miR-150-5p and PYCR1. The function of overexpression of miR-150-5p and PYCR1 were detected by cell viability, proliferation, migration and invasion in NPC C666-1 and SUNE-1 cells. RESULTS: The miR-150-5p expression was reduced in NPC tissues and cells and negatively correlated with PYCR1 level. Upregulation of miR-150-5p conspicuously repressed cell growth. However, upregulation of PYCR1 significantly facilitated the development of NPC, which further suppressed NPC tumorigenesis by abolishing the effect of miR-150-5p. CONCLUSIONS: We clarified that miR-150-5p attenuated NPC tumorigenesis through reducing PYCR1 expression. This provides a new perspective of NPC involving both miR-150-5p and PYCR1 for the treatment of NPC.

CRIF1 promotes the progression of non-small-cell lung cancer by SIRT3- mediated deacetylation of PYCR1.

Lung cancer is the cancer with the highest mortality in the world. So further exploration of the pathogenesis of lung cancer is of great significance. In this study, the specific role and related mechanism of CRIF1 in non-small cell lung cancer (NSCLC) were explored in this research. TheRT-PCR, western blot and IHC assays were used to examine the expression level of CRIF1 in NSCLC tissue, tissue adjacent to carcinoma, NSCLC cell lines and human normal lung epithelial cells. Next, colony formation assay, Alamar blue Kit and EdU assays were employed to examine the proliferation of transfected A549 and NCI-H2009 cells. Measurement of mitochondrial permeability transition pore opening, ATP production and cellular oxygen consumption were used to evaluate the mitochondrial apoptosis of transfected NSCLC cells. Enzymatic activity assays for PYCR1, western blot and flow cytometry assays were used to explore the relationship between PYCR1 and CRIF1. The subcutaneous xenograft tumor mice model was established to explore the role of CRIF1 in vivo. Collectively, results revealed that CRIF1 was upregulated in NSCLC cells and tissues (p < 0.001). CRIF1 promoted proliferation of NSCLC cells (p < 0.001). CRIF1 inhibited mitochondrial apoptosis in NSCLC cells (p < 0.05). Moreover, CRIF1 promoted PYCR1 deacetylation and increased its activity through SIRT3 (p < 0.05). Deacetylation of PYCR1 reversed the antitumor effect of CRIF1 knockdown (p < 0.05). Finally, knockdown of CRIF1 inhibited the tumor growth of NSCLC in vivo (p < 0.05).This research found that CRIF1 promoted the progression of non-small-cell lung cancer by SIRT3- mediated deacetylation of PYCR1.

PYCR1: A Potential Prognostic Biomarker in Pancreatic Ductal Adenocarcinoma.

Background/Objectives: Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignant tumor with an extremely poor prognosis in digestive tumors. Pyrroline-5-carboxylate reductase 1 (PYCR1) plays an important role in tumor development. Therefore, we aimed to explore the effect of PYCR1 on the growth of PDAC cells. Methods: Tumor tissues and adjacent normal pancreatic tissues were collected from 89 patients with PDAC. And immunohistochemistry (IHC) was used to analyze the expression level of PYCR1 in both. RNA interference was used to inhibit the expression of PYCR1 in PANC- 1 and AsPC-1 cells. After infection, the expression of PYCR1 protein was detected by Western blot. The proliferation and growth of PDAC cells were detected by Celigo analysis, MTT, and clone formation assay. Cell apoptosis was analyzed by flow cytometry. Furthermore, the effect of PYCR1 interference on tumor growth was evaluated in vivo through injecting tumor cells subcutaneously into nude mice. Results: The expression of PYCR1 in pancreatic cancer tissues was significantly higher than in paired adjacent normal pancreatic tissues (P <0.01). In vitro, the downregulation of PYCR1 expression significantly inhibited the cell proliferation and colony formation, and increased apoptosis in PANC-1 cells and AsPC-1 cells compared with the shCtrl group (P <0.01). And in vivo, PYCR1 interference also significantly inhibited tumor growth both in the tumor volume and weight. Conclusion: PYCR1 interference was able to inhibit cell proliferation and promote cell apoptosis of pancreatic cancer. The PYCR1 may serve as a potential therapeutic and prognostic biomarker for the treatment of pancreatic cancer.