Proline metabolism shapes the tumor microenvironment: from collagen deposition to immune evasion

Integrating metabolomics and network pharmacology analysis to explore mechanism of Pueraria lobata against pulmonary fibrosis: Involvement of arginine metabolism pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Pueraria lobata (Willd.) Ohwi is a typical medicinal and edible plant with a long application history in China and Southeast Asia. As a widely used traditional medicine, P. lobata exhibits the properties of anti-inflammatory, antipyretic, antioxidant, relieving cough and asthma. Particularly, the increasing evidence indicates that the P. lobata has the therapeutic effect on fibrotic-related diseases in terms of metabolic regulation. However, the mechanisms of P. lobata on pulmonary fibrosis (PF) has not been thoroughly explored.

AIM OF THE STUDY

This study aimed to explore the effect of arginine metabolites of P. lobata against PF model by integrating metabolomics and network pharmacology analysis. It might provide a new idea for the target finding of P. lobata anti-pulmonary fibrosis.

MATERIALS AND METHODS

In this study, the Sprague Dawley (SD) rats were randomly divided into five experimental groups: saline-treated control group, bleomycin-induced fibrosis group, prednisolone acetate group, P. lobata 3.2 g/kg group and P. lobata 6.4 g/kg group. The therapeutic effect of P. lobata on bleomycin-induced PF in rats was evaluated by clinical symptoms such as lung function, body weight, hematoxylin eosin staining (HE), Masson staining and hydroxyproline assay. Next, the plasma metabolomics analysis was carried out by LC-MS to explore the pathological differences between the group of control, PF and P. lobata-treated rats. Then, the network pharmacology study coupled with experimental validation was conducted to analysis the results of metabolic research. We constructed the "component-target-disease" network of P. lobata in the treatment of PF. In addition, the molecular docking method was used to verify the interaction between potential active ingredients and core targets of P. lobata. Finally, we tested NOS2 and L-OT in arginine-related metabolic pathway in plasma of the rats by enzyme-linked immunosorbent assay (ELISA). Real-time PCR was performed to observe the level of TNF-α mRNA and MMP9 mRNA. And we tested the expression of TNF-α and MMP9 by Western blot analysis.

RESULTS

Our findings revealed that P. lobata improved lung function and ameliorated the pathological symptoms, such as pathological damage, collagen deposition, and body weight loss in PF rats. Otherwise, the plasma metabolomics were employed to screen the differential metabolites of amino acids, lipids, flavonoids, arachidonic acid metabolites, glycoside, etc. Finally, we found that the arginine metabolism signaling mainly involved in the regulating of P. lobata on the treatment of PF rats. Furtherly, the network pharmacology predicted that the arginine metabolism pathway was contained in the top 20 pathways. Next, we integrated metabolomics and network pharmacology that identified NOS2, MMP9 and TNF-α as the P. lobata regulated hub genes by molecular docking. Importantly, it indicated a strong affinity between the puerarin and the NOS2. P. lobata attenuated TNF-α, MMP-9 and NOS2 levels, suppressed TNF-α and MMP-9 protein expression, and decreased L-OT and NOS2 content in PF rats. These results indicated that the effects of P. lobata may ameliorated PF via the arginine metabolism pathway in rats. Therefore, P. lobata may be a potential therapeutic agent to ameliorated PF.

CONCLUSION

In this work, we used metabolomics and network pharmacology to explore the mechanisms of P. lobata in the treatment of PF. Finally, we confirmed that P. lobata alleviated BLM-induced PF in rats by regulating arginine metabolism pathway based on reducing the L-OT and NOS2-related signal molecular. The search for the biomarkers finding of arginine metabolism pathway revealed a new strategy for P. lobata in the treatment of PF.

Recent advances in understanding the immune microenvironment in ovarian cancer

The occurrence of ovarian cancer (OC) is a major factor in women's mortality rates. Despite progress in medical treatments, like new drugs targeting homologous recombination deficiency, survival rates for OC patients are still not ideal. The tumor microenvironment (TME) includes cancer cells, fibroblasts linked to cancer (CAFs), immune-inflammatory cells, and the substances these cells secrete, along with non-cellular components in the extracellular matrix (ECM). First, the TME mainly plays a role in inhibiting tumor growth and protecting normal cell survival. As tumors progress, the TME gradually becomes a place to promote tumor cell progression. Immune cells in the TME have attracted much attention as targets for immunotherapy. Immune checkpoint inhibitor (ICI) therapy has the potential to regulate the TME, suppressing factors that facilitate tumor advancement, reactivating immune cells, managing tumor growth, and extending the survival of patients with advanced cancer. This review presents an outline of current studies on the distinct cellular elements within the OC TME, detailing their main functions and possible signaling pathways. Additionally, we examine immunotherapy rechallenge in OC, with a specific emphasis on the biological reasons behind resistance to ICIs.

PYCR3 modulates mtDNA copy number to drive proliferation and doxorubicin resistance in triple-negative breast cancer

Triple-negative breast cancer (TNBC) poses significant challenges in treatment due to its aggressive nature and limited therapeutic targets. Understanding the underlying molecular mechanisms driving TNBC progression and chemotherapy resistance is imperative for developing effective therapeutic strategies. Thus, in this study, we aimed to elucidate the role of pyrroline-5-carboxylate reductase 3 (PYCR3) in TNBC pathogenesis and therapeutic response. We observed that PYCR3 is significantly upregulated in TNBC specimens compared to normal breast tissues, correlating with a poorer prognosis in TNBC patients. Knockdown of PYCR3 not only suppresses TNBC cell proliferation but also reverses acquired resistance of TNBC cells to doxorubicin, a commonly used chemotherapeutic agent. Mechanistically, we identified the mitochondrial localization of PYCR3 in TNBC cells and demonstrated its impact on TNBC cell proliferation and sensitivity to doxorubicin through the regulation of mtDNA copy number and mitochondrial respiration. Importantly, Selective reduction of mtDNA copy number using the mtDNA replication inhibitor 2', 3'-dideoxycytidine effectively recapitulates the phenotypic effects observed in PYCR3 knockout, resulting in decreased TNBC cell proliferation and the reversal of doxorubicin resistance through apoptosis induction. Thus, our study underscores the clinical relevance of PYCR3 and highlight its potential as a therapeutic target in TNBC management. By elucidating the functional significance of PYCR3 in TNBC, our findings contribute to a deeper understanding of TNBC biology and provide a foundation for developing novel therapeutic strategies aimed at improving patient outcomes.

Dendritic Polymer-Based Nanomedicines Remodel the Tumor Stroma: Improve Drug Penetration and Enhance Antitumor Immune Response

The dense extracellular matrix (ECM) in solid tumors, contributed by cancer-associated fibroblasts (CAFs), hinders penetration of drugs and diminishes their therapeutic outcomes. A sequential treatment strategy of remodeling the ECM via a CAF modifier (dasatinib, DAS) is proposed to promote penetration of an immunogenic cell death (ICD) inducer (epirubicin, Epi) via apoptotic vesicles, ultimately enhancing the treatment efficacy against breast cancer. Dendritic poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA)-based nanomedicines (poly[OEGMA-Dendron(G2)-Gly-Phe-Leu-Gly-DAS] (P-DAS) and poly[OEGMA-Dendron(G2)-hydrazone-Epi] (P-Epi)) are developed for sequential delivery of DAS and Epi, respectively. P-DAS reprograms CAFs to reduce collagen by downregulating collagen anabolism and energy metabolism, thereby reducing the ECM deposition. The regulated ECM can enhance tumor penetration of P-Epi to strengthen its ICD effect, leading to an amplified antitumor immune response. In breast cancer-bearing mice, this approach alleviates the ECM barrier, resulting in reduced tumor burden and increased cytotoxic T lymphocyte infiltration, and more encouragingly, synergizes effectively with anti-programmed cell death 1 (PD-1) therapy, significantly inhibiting tumor growth and preventing lung metastasis. Furthermore, systemic toxicity is barely detectable after sequential treatment with P-DAS and P-Epi. This approach opens a new avenue for treating desmoplastic tumors by metabolically targeting CAFs to overcome the ECM barrier.

Influence of proline and hydroxyproline as antimicrobial and anticancer peptide components on the silver(I) ion activity: structural and biological evaluation with a new theoretical and experimental SAR approach

Silver(I) complexes with proline and hydroxyproline were synthesized and structurally characterized and crystal structure analysis shows that the formulas of the compounds are {[Ag2(Pro)2(NO3)]NO3}n (AgPro) (Pro = L-proline) and {[Ag2(Hyp)2(NO3)]NO3}n (AgHyp) (Hyp = trans-4-hydroxy-L-proline). Both complexes crystallize in the monoclinic lattice with space group P21 with a carboxylate bidentate-bridging coordination mode of the organic ligands Pro and Hyp (with NH2+ and COO- groups in zwitterionic form). Both complexes have a distorted seesaw (C2v) geometry around one silver(I) ion with τ4 values of 58% (AgPro) and 51% (AgHyp). Moreover, the results of spectral and thermal analyses correlate with the structural ones. 1H and 13C NMR spectra confirm the complexes species' presence in the DMSO biological testing medium and their stability in the time range of the bioassays. In addition, molar conductivity measurements indicate complexes' behaviour like 1 : 1 electrolytes. Both complexes showed higher or the same antibacterial activity against Bacillus cereus, Pseudomonas aeruginosa and Staphylococcus aureus as AgNO3 (MIC = 0.063 mM) and higher than silver(I) sulfadiazine (AgSD) (MIC > 0.5 mM) against Pseudomonas aeruginosa. In addition, complex AgPro exerted a strong cytotoxic effect against the tested MDA-MB-231 and Jurkat cancer cell lines (IC50 values equal to 3.7 and 3.0 μM, respectively) compared with AgNO3 (IC50 = 6.1 (5.7) μM) and even significantly higher selectivity than cisplatin (cisPt) against MDA-MB-231 cancer cell lines (SI = 3.05 (AgPro); 1.16 (cisPt), SI - selectivity index). The binding constants and the number of binding sites (n) of AgPro and AgHyp complexes with bovine serum albumin (BSA) were determined at four different temperatures, and the zeta potential of BSA in the presence of silver(I) complexes was also measured. The in ovo method shows the safety of the topical and intravenous application of AgPro and AgHyp. Moreover, the complexes' bioavailability was verified by lipophilicity evaluation from the experimental and theoretical points of view.

The Role of Amino Acids in Non-Enzymatic Antioxidant Mechanisms in Cancer: A Review

Currently, the antioxidant properties of amino acids and their role in the physicochemical processes accompanying oxidative stress in cancer remain unclear. Cancer cells are known to extensively uptake amino acids, which are used as an energy source, antioxidant precursors that reduce oxidative stress in cancer, and as regulators of inhibiting or inducing tumor cell-associated gene expression. This review examines nine amino acids (Cys, His, Phe, Met, Trp, Tyr, Pro, Arg, Lys), which play a key role in the non-enzymatic oxidative process in various cancers. Conventionally, these amino acids can be divided into two groups, in one of which the activity increases (Cys, Phe, Met, Pro, Arg, Lys) in cancer, and in the other, it decreases (His, Trp, Tyr). The review examines changes in the metabolism of nine amino acids in eleven types of oncology. We have identified the main nonspecific mechanisms of changes in the metabolic activity of amino acids, and described direct and indirect effects on the redox homeostasis of cells. In the future, this will help to understand better the nature of life of a cancer cell and identify therapeutic targets more effectively.