Dexamethasone inhibits the proliferation of tumor cells

Exploring New Frontiers: Alternative Breast Cancer Treatments Through Glycocalyx Research

Breast cancer (BC) treatment is developing toward more precise and personalized care through the approval of different comprehensive approaches. Clinical practice emphasizes significant patient-to-patient variability in treatment response among patients, even those with similar clinical and biological profiles. Recent studies have demonstrated that the glycocalyx is an essential organelle that plays an important role in many cellular processes and can be a promising target for treatment. The glycocalyx of cancer cells is a key component influencing the interaction between the tumor and the immune system. Glycan modifications attached to glycoproteins and glycolipids are a common characteristic of the transition to malignancy. We review how the specific structure and function of the glycocalyx are regulated at the molecular level, contribute to immune evasion, and can be overcome by using both traditional drugs and combination therapies, as well as drugs not previously used in standard cancer treatments, to address treatment resistance associated with glycocalyx alterations. Trial Registration: ClinicalTrials.gov identifier: NCT00770354, NCT00925548, NCT01731587, NCT00088413, NCT00179309, NCT00986609, NCT05812326, NCT04020575, NCT05239143, NCT01279603, and NCT03562637.

Dysregulation of phosphoenolpyruvate carboxykinase in cancers: A comprehensive analysis

BACKGROUND

Phosphoenolpyruvate carboxykinase (PEPCK) plays a crucial role in gluconeogenesis, glycolysis, and the tricarboxylic acid cycle by converting oxaloacetate into phosphoenolpyruvate. Two distinct isoforms of PEPCK, specifically cytosolic PCK1 and mitochondrial PCK2, have been identified. Nevertheless, the comprehensive understanding of their dysregulation in pan-cancer and their potential mechanism contributing to signaling transduction pathways remains elusive.

METHODS

We conducted comprehensive analyses of PEPCK gene expression across 33 diverse cancer types using data from The Cancer Genome Atlas (TCGA). Multiple public databases such as HPA, TIMER 2.0, GEPIA2, cBioPortal, UALCAN, CancerSEA, and String were used to investigate protein levels, prognostic significance, clinical associations, genetic mutations, immune cell infiltration, single-cell sequencing, and functional enrichment analysis in patients with pan-cancer. PEPCK expression was analyzed about different clinical and genetic factors of patients using data from TCGA, GEO, and CGGA databases. Furthermore, the role of PCK2 in Glioma was examined using both in vitro and in vivo experiments.

RESULTS

The analysis we conducted revealed that the expression of PEPCK is involved in both clinical outcomes and immune cell infiltration. Initially, we verified the high expression of PCK2 in GBM cells and its role in metabolic reprogramming and proliferation in GBM.

CONCLUSION

Our study showed a correlation between PEPCK (PCK1 and PCK2) expression with clinical prognosis, gene mutation, and immune infiltrates. These findings identified two possible predictive biomarkers across different cancer types, as well as a comprehensive analysis of PCK2 expression in various tumors, with a focus on GBM.

Strategy of targeting the tumor microenvironment via inhibition of fibroblast/fibrosis remodeling new era to cancer chemo-immunotherapy resistance

The use of repurposing drugs that may have neoplastic and anticancer effects increases the efficiency and decrease resistance to chemotherapy drugs through a biochemical and mechanical transduction mechanisms through modulation of fibroblast/fibrosis remodeling in tumor microenvironment (TME). Interestingly, fibroblast/fibrosis remodeling plays a vital role in mediating cancer metastasis and drug resistance after immune chemotherapy. The most essential hypothesis for induction of chemo-immunotherapy resistance is via activation of fibroblast/fibrosis remodeling and preventing the infiltration of T cells after is mainly due to the interference between cytoskeleton, mechanical, biochemical, metabolic, vascular, and remodeling signaling pathways in TME. The structural components of the tumor that can be targeted in the fibroblast/fibrosis remodeling include the depletion of the TME components, targeting the cancer-associated fibroblasts and tumor associated macrophages, alleviating the mechanical stress within the ECM, and normalizing the blood vessels. It has also been found that during immune-chemotherapy, TME injury and fibroblast/fibrosis remodeling causes the up-regulation of inhibitory signals and down-regulation of activated signals, which results in immune escape or chemo-resistance of the tumor. In this regard, repurposing or neo-adjuvant drugs with various transduction signaling mechanisms, including anti-fibrotic effects, are used to target the TME and fibroblast/fibrosis signaling pathway such as angiotensin 2, transforming growth factor-beta, physical barriers of the TME, cytokines and metabolic factors which finally led to the reverse of the chemo-resistance. Consistent to many repurposing drugs such as pirfenidone, metformin, losartan, tranilast, dexamethasone and pentoxifylline are used to decrease immune-suppression by abrogation of TME inhibitory signal that stimulates the immune system and increases efficiency and reduces resistance to chemotherapy drugs. To overcome immunosuppression based on fibroblast/fibrosis remodeling, in this review, we focus on inhibitory signal transduction, which is the physical barrier, alleviates mechanical stress and prevents mechano-metabolic activation.

Dexamethasone Selectively Inhibits Detachment of Metastatic Thyroid Cancer Cells during Random Positioning

We recently reported that synthetic glucocorticoid dexamethasone (DEX) is able to suppress metastasis-like spheroid formation in a culture of follicular thyroid cancer (FTC)-133 cells cultured under random positioning. We now show that this inhibition was selective for two metastatic thyroid carcinoma cells, FTC-133 and WRO, whereas benign Nthy-ori 3-1 thyrocytes and recurrent ML-1 follicular thyroid cancer cells were not affected by DEX. We then compare Nthy-ori 3-1 and FTC-133 cells concerning their adhesion and mechanosignaling. We demonstrate that DEX disrupts random positioning-triggered p38 stress signaling in FTC-133 cells, thereby antagonizing a variety of biological functions. Thus, DEX treatment of FTC-133 cells is associated with increased adhesiveness, which is mainly caused by the restored, pronounced formation of a normal number of tight junctions. Moreover, we show that Nthy-ori 3-1 and ML-1 cells upregulate the anti-adhesion protein mucin-1 during random positioning, presumably as a protection against mechanical stress. In summary, mechanical stress seems to be an important component in this metastasis model system that is processed differently by metastatic and healthy cells. The balance between adhesion, anti-adhesion and cell–cell connections enables detachment of adherent human cells on the random positioning machine—or not, allowing selective inhibition of thyroid in vitro metastasis by DEX.

Dexamethasone Is Not Sufficient to Facilitate Tenogenic Differentiation of Dermal Fibroblasts in a 3D Organoid Model

Self-assembling three-dimensional organoids that do not rely on an exogenous scaffold but maintain their native cell-to-cell and cell-to-matrix interactions represent a promising model in the field of tendon tissue engineering. We have identified dermal fibroblasts (DFs) as a potential cell type for generating functional tendon-like tissue. The glucocorticoid dexamethasone (DEX) has been shown to regulate cell proliferation and facilitate differentiation towards other mesenchymal lineages. Therefore, we hypothesized that the administration of DEX could reduce excessive DF proliferation and thus, facilitate the tenogenic differentiation of DFs using a previously established 3D organoid model combined with dose-dependent application of DEX. Interestingly, the results demonstrated that DEX, in all tested concentrations, was not sufficient to notably induce the tenogenic differentiation of human DFs and DEX-treated organoids did not have clear advantages over untreated control organoids. Moreover, high concentrations of DEX exerted a negative impact on the organoid phenotype. Nevertheless, the expression profile of tendon-related genes of untreated and 10 nM DEX-treated DF organoids was largely comparable to organoids formed by tendon-derived cells, which is encouraging for further investigations on utilizing DFs for tendon tissue engineering.

T Cell Energy Metabolism Is a Target of Glucocorticoids in Mice, Healthy Humans, and MS Patients

Glucocorticoids (GCs) are used to treat inflammatory disorders such as multiple sclerosis (MS) by exerting prominent activities in T cells including apoptosis induction and suppression of cytokine production. However, little is known about their impact on energy metabolism, although it is widely accepted that this process is a critical rheostat of T cell activity. We thus tested the hypothesis that GCs control genes and processes involved in nutrient transport and glycolysis. Our experiments revealed that escalating doses of dexamethasone (Dex) repressed energy metabolism in murine and human primary T cells. This effect was mediated by the GC receptor and unrelated to both apoptosis induction and Stat1 activity. In contrast, treatment of human T cells with rapamycin abolished the repression of metabolic gene expression by Dex, unveiling mTOR as a critical target of GC action. A similar phenomenon was observed in MS patients after intravenous methylprednisolon (IVMP) pulse therapy. The expression of metabolic genes was reduced in the peripheral blood T cells of most patients 24 h after GC treatment, an effect that correlated with disease activity. Collectively, our results establish the regulation of T cell energy metabolism by GCs as a new immunomodulatory principle.

Advantages and drawbacks of dexamethasone in glioblastoma multiforme

The most widespread, malignant, and deadliest type of glial tumor is glioblastoma multiforme (GBM). Despite radiation, chemotherapy, and radical surgery, the median survival of afflicted individuals is about 12 months. Unfortunately, existing therapeutic interventions are abysmal. Dexamethasone (Dex), a synthetic glucocorticoid, has been used for many years to treat brain edema and inflammation caused by GBM. Several investigations have recently shown that Dex also exerts antitumoral effects against GBM. On the other hand, more recent disputed findings have questioned the long-held dogma of Dex treatment for GBM. Unfortunately, steroids are associated with various undesirable side effects, including severe immunosuppression and metabolic changes like hyperglycemia, which may impair the survival of GBM patients. Current ideas and concerns about Dex's effects on GBM cerebral edema, cell proliferation, migration, and its clinical outcomes were investigated in this study.

Therapeutic potential and deleterious effect of glucocorticoids on azoxymethane/dextran sulfate sodium-induced colorectal cancer in mice

Glucocorticoids (GCs) are widely used in the treatment of various autoimmune and inflammatory diseases, including inflammatory bowel disease (IBD). However, the effect of GCs on the progression of colitis-associated colorectal cancer (CAC) has not been well explored. In this study, we first established a colorectal cancer model induced by azoxymethane and dextran sulfate sodium (AOM/DSS) and a colitis model induced by DSS in mice. Dexamethasone (DEX) was then administered at different periods of time to determine its effect on tumorigenesis and tumor progression. Meanwhile, body weight, stool property and fecal blood of mice were recorded. At the end of this study, the number and load of tumors were evaluated, and the expression of proteins associated with cell proliferation was analyzed. To evaluate the inflammation in colon, we detected the level of pro-inflammatory cytokine TNFα, and the mucosal infiltration of inflammatory cells. Our results revealed that AOM injection followed by three cycles of drinking water containing 1.5% DSS successfully induced multiple tumor formation in mouse colon and rectum. Both early and late DEX intervention suppressed tumor growth in mouse colorectum, and downregulated the expression of PCNA and cyclin D1. Moreover, DEX treatment significantly inhibited TNFα production, mucosal infiltration of inflammatory cells, and the activity of MAPK/JNK pathway, particularly early DEX intervention. However, we also found that DEX treatment deteriorated the general state of mouse manifested by greater loss of body weight and rectal bleeding. In summary, both early and late DEX interventions significantly ameliorate colonic inflammation and inhibit the progression of AOM/DSS-induced colorectal cancer, at least partly due to the inhibition of MAPK/JNK pathway. It is noteworthy that the deleterious effect on the general condition of mouse may limit the duration of GCs treatment.

A novel mutation in PCK2 gene causes primary angle-closure glaucoma

Primary angle-closure glaucoma (PACG) is an ophthalmic genetic disease characterized by direct contact between the iris and trabecular meshwork, resulting in an obstructed outflow of aqueous humor from the eye. However, it is unclear as to what role genetics plays in the development of PACG. The present study investigated the disease-causing mutation in a five-generation Chinese PACG family using whole-genome sequencing. A novel heterozygous missense mutation c.977C>T in PCK2 gene was identified in five affected family members, but not in any unaffected and 86 unrelated healthy individuals. This nucleotide substitute is predicted to result in a proline to leucine substitution p.Pro326Leu. Furthermore, the function of this mutation was analyzed through various in vitro assays using the RGC-5 cell line. Our results demonstrate that the p.Pro326Leu mutation induces RGC-5 cell cycle arrest and apoptosis with a decreased BcL-XL. The increasing P53, P27, P21, AKT, and P-GSK3α were also detected in the cells transfected with c.977C>T mutation, suggesting that this mutation within PCK2 gene cause PACG through impairment of AKT/GSK3α signaling pathway.

Differential Impacts of Phenol Red on Benzo[a]pyrene and Dexamethasone-Modified Cytochrome P450s in Human Cancer Cells

<b>Background and Objective:</b> Phenol red, the pH indicator in cell culture media, influences the expression of cytochrome P450s (CYPs) in cell lines. This study aimed to examine how phenol red modified CYP induction by benzo[<i>a</i>]pyrene and dexamethasone in human hepatocarcinoma (HepG2), colorectal adenocarcinoma (Caco-2) and choriocarcinoma (BeWo) cells. <b>Materials and Methods:</b> The cells (1×10<sup>5</sup> cells/well in a 24-well plate) were incubated with benzo[<i>a</i>]pyrene (0.1, 1 and 10 μM) or dexamethasone (1, 5 and 10 μM) in either phenol red or phenol red-free media for 24 hrs. The mRNA expression of CYPs was determined by Real-Time Polymerase Chain Reaction (RT/qPCR). <b>Results:</b> Phenol red enhanced expression of benzo[<i>a</i>]pyrene-induced CYP1A2 inHepG2 and BeWo cells and suppressed benzo[<i>a</i>]pyrene-induced CYP2A6 expression in HepG2 and Caco-2 cells, benzo[<i>a</i>]pyrene induced CYP2B6 expression in HepG2 cells and benzo[<i>a</i>]pyrene- and dexamethasone-induced CYP3A4 expression in HepG2 and Caco-2 cells. The expression of CYP3A5 was affected differently in HepG2 and Caco-2 cell lines. Phenol red enhanced benzo[<i>a</i>]pyrene- and dexamethasone-induced CYP3A5 expression in Caco-2 cells but suppressed benzo[<i>a</i>]pyrene- and dexamethasone-induced CYP3A5 expression in HepG2 cells. <b>Conclusion:</b> Phenol red differentially influenced expression of benzo[<i>a</i>]pyrene- and dexamethasone-induced CYP1A2, CYP2A6, CYP2B6, CYP3A4 and CYP3A5 mRNAs in HepG2, Caco-2 and BeWo cells. Therefore, the inclusion of phenol red in cell culture media is of concern in studies of drug and xenobiotic metabolism via CYPs in human cell line models.

Oridonin interrupts cellular bioenergetics to suppress glioma cell growth by down-regulating PCK2

We aim to evaluate the tumor metabolic suppressive activity of Oridonin (extract of Rabdosia rubescens) in glioma and elucidate its potential mechanism. Effects of Oridonin on U251/U87 cells were determined by CCK8, RTCA, colony formation, flow cytometry, wound healing, and Transwell assay. Xenograft tumor model to evaluate the effect of Oridonin on glioma cells in vivo. Cellular bioenergetics were measured by Seahorse. RNA-seq was performed to screen potential biological pathways in Oridonin treated cells. Bioinformatics analysis of PCK2 in glioma was performed based on TCGA/CGGA. Endogenous PCK2 was knocked-down by lentivirus packaged shRNA. We found Oridonin significantly inhibited cell growth in U251/U87 in vitro and in vivo. Both oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) were decreased in Oridonin-treated U251/U87 cells. Oridonin treatment led to PCK2 down-regulation. Additionally, PCK2 was up-regulated in higher grade glioma and correlated with poor outcomes. Furthermore, PCK2 depletion significantly inhibited cell growth and decreased OCR/ECAR in U251/U87 which coincided with the effects of Oridonin. Therefore, we evaluated the potent anti-tumor property of Oridonin in glioma. Importantly, we demonstrated that PCK2 might be a novel target of Oridonin on glioma by inducing energy crisis and increasing oxidative stress.

Trichostatin A sensitizes hepatoma cells to Taxol more than 5-Aza-dC and dexamethasone

OBJECTIVES

This work was designed to compare the sensitizing effects of epigenetic modifiers on cancer cells vs. that of glucocorticoids. Also, to evaluate their effects on genes involved in epigenetic changes and drug metabolism.

METHODS

Hepatoma cells (HepG2) were treated with the anticancer drug (Taxol), with a histone deacetylase inhibitor (Trichostatin A [TSA]), DNA methyltransferase inhibitor (5-Aza-dC) or dexamethasone (DEX). Cytotoxicity was assessed by MTT assay and the apoptosis was determined by Annexin V-FITC. The expression levels of HDAC1, HDAC3, Dnmt1, Dnmt3α, CYP1A2, CYP3A4, CYP2B6, CYP2C19 and CYP2D6 were monitored by qRT-PCR.

RESULTS

TSA, synergistically enhanced cells sensitivity with the anticancer effect of Taxol more than 5-Aza-dC and DEX. This was evidenced by the relative decrease in IC₅₀ in cells cotreated with Taxol + TSA, Taxol + 5-Aza-dC or Taxol + DEX. Apoptosis was induced in 51.2, 16.9 and 41.3% of cells, respectively. In presence of Taxol, TSA induced four-fold increase in the expression of HDAC1 and downregulated Dnmt1&3α genes. CYP2D6 demonstrated progressive expression (up to 28-fold) with the increasing number of drugs. Moreover, the isoform overexpressed in cells treated with TSA + Taxol > DEX + Taxol > 5-Aza-dC + Taxol (6.4, 4.6 and 2.99, respectively). The investigated genes were clustered in two distinct subsets, where no coregulation was observed between HDAC1 and HDAC3. However, tight pairwise correlation-based cluster was seen between (CYP3A4/Dnmt3α and CYP2D6/CYP2C19).

CONCLUSIONS

The data reflects the sensitizing effect of acetylation modification by TSA on the responsiveness of hepatoma cells to anticancer therapy. The effect of histone deacetylase inhibition was more than hypomethylation and glucocorticoid effects. TSA exerts its role through its modulatory role on epigenetics and drugs metabolizing genes. Other modifiers (5-Aza-dC and DEX), however may adopt different mechanisms.

Trichostatin A sensitizes hepatoma cells to Taxol more than 5-Aza-dC and dexamethasone

OBJECTIVES

This work was designed to compare the sensitizing effects of epigenetic modifiers on cancer cells vs. that of glucocorticoids. Also, to evaluate their effects on genes involved in epigenetic changes and drug metabolism.

METHODS

Hepatoma cells (HepG2) were treated with the anticancer drug (Taxol), with a histone deacetylase inhibitor (Trichostatin A [TSA]), DNA methyltransferase inhibitor (5-Aza-dC) or dexamethasone (DEX). Cytotoxicity was assessed by MTT assay and the apoptosis was determined by Annexin V-FITC. The expression levels of HDAC1, HDAC3, Dnmt1, Dnmt3α, CYP1A2, CYP3A4, CYP2B6, CYP2C19 and CYP2D6 were monitored by qRT-PCR.

RESULTS

TSA, synergistically enhanced cells sensitivity with the anticancer effect of Taxol more than 5-Aza-dC and DEX. This was evidenced by the relative decrease in IC50 in cells cotreated with Taxol + TSA, Taxol + 5-Aza-dC or Taxol + DEX. Apoptosis was induced in 51.2, 16.9 and 41.3% of cells, respectively. In presence of Taxol, TSA induced four-fold increase in the expression of HDAC1 and downregulated Dnmt1&3α genes. CYP2D6 demonstrated progressive expression (up to 28-fold) with the increasing number of drugs. Moreover, the isoform overexpressed in cells treated with TSA + Taxol > DEX + Taxol > 5-Aza-dC + Taxol (6.4, 4.6 and 2.99, respectively). The investigated genes were clustered in two distinct subsets, where no coregulation was observed between HDAC1 and HDAC3. However, tight pairwise correlation-based cluster was seen between (CYP3A4/Dnmt3α and CYP2D6/CYP2C19).

CONCLUSIONS

The data reflects the sensitizing effect of acetylation modification by TSA on the responsiveness of hepatoma cells to anticancer therapy. The effect of histone deacetylase inhibition was more than hypomethylation and glucocorticoid effects. TSA exerts its role through its modulatory role on epigenetics and drugs metabolizing genes. Other modifiers (5-Aza-dC and DEX), however may adopt different mechanisms.

Dexamethasone Promotes Aspergillus fumigatus Growth in Macrophages by Triggering M2 Repolarization via Targeting PKM2

Since long-term corticosteroid treatment is associated with emerging opportunistic fungal infections causing high morbidity and mortality in immune-suppressed individuals, here we characterized the impact of dexamethasone (Dex) treatment on Aspergillus fumigatus-related immune modulation. We found by high content screening and flow cytometric analyses that during monocyte-to-macrophage differentiation, as little as 0.1 µg/mL Dex resulted in a shift in macrophage polarization from M1 to M2-like macrophages. This macrophage repolarization mediated via Dex was characterized by significant upregulation of the M2 marker CD163 and downmodulation of M1 markers CD40 and CD86 as well as changes in phenotypic properties and adherence. These Dex-mediated phenotypic alterations were furthermore associated with a metabolic switch in macrophages orchestrated via PKM2. Such treated macrophages lost their ability to prevent Aspergillus fumigatus germination, which was correlated with accelerated fungal growth, destruction of macrophages, and induction of an anti-inflammatory cytokine profile. Taken together, repolarization of macrophages following corticosteroid treatment and concomitant switch to an anti-inflammatory phenotype might play a prominent role in triggering invasive aspergillosis (IA) due to suppression of innate immunological responses necessary to combat extensive fungal outgrowth.

Deep immune profiling of ovarian tumors identifies minimal MHC-I expression after neoadjuvant chemotherapy as negatively associated with T-cell-dependent outcome

Epithelial Ovarian cancer (EOC) is the most lethal gynecological malignancy and has limited curative therapeutic options. Immunotherapy for EOC is promising, but clinical efficacy remains restricted to a small percentage of patients. Several lines of evidence suggest that the low response rate might be improved by combining immunotherapy with carboplatin and paclitaxel, the standard-of-care chemotherapy for EOC. Here, we assessed the immune contexture of EOC tumors, draining lymph nodes, and peripheral blood mononuclear cells during carboplatin/paclitaxel chemotherapy. We observed that the immune contexture of EOC patients is defined by the tissue of origin, independent of exposure to chemotherapy. Summarized, draining lymph nodes were characterized by a quiescent microenvironment composed of mostly non-proliferating naïve CD4 + T cells. Circulating T cells shared phenotypic features of both lymph nodes and tumor-infiltrating immune cells. Immunologically 'hot' ovarian tumors were characterized by ICOS, GITR, and PD-1 expression on CD4 + and CD8 + cells, independent of chemotherapy. The presence of PD-1 + cells in tumors prior to, but not after, chemotherapy was associated with disease-specific survival (DSS). Accordingly, we observed high MHC-I expression in tumors prior to chemotherapy, but minimal MHC-I expression in tumors after neoadjuvant chemotherapy, even though there were no differences in the number of tumor-infiltrating lymphocytes (TIL) in both groups. We therefore speculate that the TIL influx into the chemotherapy tumor microenvironment may be a consequence of the general inflammatory nature of chemotherapy-experienced tumors. Strategies to upregulate MHC-I during or after neoadjuvant chemotherapy may thus improve treatment outcome in these patients.

High-Dose Dexamethasone Manipulates the Tumor Microenvironment and Internal Metabolic Pathways in Anti-Tumor Progression

High-dose dexamethasone (DEX) is used to treat chemotherapy-induced nausea and vomiting or to control immunotherapy-related autoimmune diseases in clinical practice. However, the underlying mechanisms of high-dose DEX in tumor progression remain unaddressed. Therefore, we explored the effects of high-dose DEX on tumor progression and the potential mechanisms of its anti-tumor function using immunohistochemistry, histological examination, real-time quantitative PCR (qPCR), and Western blotting. Tumor volume, blood vessel invasion, and levels of the cell proliferation markers Ki67 and c-Myc and the anti-apoptotic marker Bcl2 decreased in response to high-dose DEX. However, the cell apoptosis marker cleaved caspase 3 increased significantly in mice treated with 50 mg/kg DEX compared with controls. Some genes associated with immune responses were significantly downregulated following treatment with 50 mg/kg DEX e.g., Cxcl9, Cxcl10, Cd3e, Gzmb, Ifng, Foxp3, S100a9, Arg1, and Mrc1. In contrast, the M1-like tumor-associated macrophages (TAMs) activation marker Nos2 was shown to be increased. Moreover, the expression of peroxisome proliferator-activated receptors α and γ (Pparα and Pparg, respectively) was shown to be significantly upregulated in livers or tumors treated with DEX. However, high-dose DEX treatment decreased the expression of glucose and lipid metabolic pathway-related genes such as glycolysis-associated genes (Glut1, Hk2, Pgk1, Idh3a), triglyceride (TG) synthesis genes (Gpam, Agpat2, Dgat1), exogenous free fatty acid (FFA) uptake-related genes (Fabp1, Slc27a4, and CD36), and fatty acid oxidation (FAO) genes (Acadm, Acaa1, Cpt1a, Pnpla2). In addition, increased serum glucose and decreased serum TG and non-esterified fatty acid (NEFA) were observed in DEX treated-xenografted tumor mice. These findings indicate that high-dose DEX-inhibited tumor progression is a complicated process, not only activated by M1-like TAMs, but also decreased by the uptake and consumption of glucose and lipids that block the raw material and energy supply of cancer cells. Activated M1-like TAMs and inefficient glucose and lipid metabolism delayed tumor cell growth and promoted apoptosis. These findings have important implications for the application of DEX combined with drugs that target key metabolism pathways for tumor therapy in clinical practice.

Metronomic paclitaxel improves the efficacy of PD-1 monoclonal antibodies in breast cancer by transforming the tumor immune microenvironment

The clinical efficacy of PD-1/PD-L1 monoclonal antibodies (mAbs) in triple-negative breast cancer (TNBC) is unsatisfactory. Immunotherapy combined with chemotherapy shows good therapeutic potential. Preclinical and clinical studies have shown that metronomic chemotherapy may stimulate anticancer immune responses. We aimed to verify whether metronomic paclitaxel (PTX, TAX) treatment can improve the efficacy of a PD-1 mAb in a TNBC mouse model and to explore the potential mechanism. After constructing the TNBC mouse model and treating with PD-1 mAb, metronomic PTX chemotherapy or combined therapy, the differences in the efficacy of each treatment group were compared and analyzed. Our findings suggested that the combination of metronomic PTX chemotherapy and PD-1 mAb produces a potent antitumor effect. Further experiments demonstrated that metronomic PTX chemotherapy changed the immune cell population in tumor tissues. These data suggest that metronomic PTX improves the efficacy of the PD-1 mAb in TNBC by transforming the tumor immune microenvironment, and these results provide strong evidence for the use of this treatment in TNBC patients in the future.