Tumor Growth In Model Research Articles

Simplified Lipid Nanoparticles for Tissue- And Cell-Targeted mRNA Delivery Facilitate Precision Tumor Therapy in a Lung Metastasis Mouse Model.

mRNA-based applications have achieved remarkable success in the development of next-generation vaccines and the treatment of diverse liver diseases. Overcoming the challenge of delivering mRNA to extrahepatic tissues, especially specific cells within tissues, is crucial for precision therapy. In this study, a platform is developed for selective mRNA delivery to desired cells within tissues by combining lipid nanoparticle (LNP)-based targeted delivery with mRNA sequence-controlled expression. Through systematic optimization, a three-component LNP platform is developed, enabling targeted mRNA delivery to the lung, liver, and spleen. The incorporation of unique microRNA target sites into the mRNA scaffold further enhances control over protein translation in specific cells within the target tissue. This combined strategy, named SELECT (Simplified LNP with Engineered mRNA for Cell-type Targeting), demonstrates its efficacy in distinguishing mRNA expression between tumor and normal cells based on intracellular microRNA abundance. SELECT encapsulating mRNA encoding a tumor-specific cytotoxic protein, human ELANE, exhibits selective mRNA delivery to tumor lesions and significant inhibition of tumor growth in a mouse model of melanoma lung metastasis. Overall, SELECT has great potential as a new precision tumor treatment approach and also offers promising prospects for other mRNA therapies targeting specific cell types.

Discovery of Novel 5-(Pyridazin-3-yl)pyrimidine-2,4(1H,3H)-dione Derivatives as Potent and Orally Bioavailable Inhibitors Targeting Ecto-5'-nucleotidase.

Ecto-5-nucleotidase (CD73) is overexpressed in a variety of cancers and associated with the immunosuppressive tumor microenvironment, making it an attractive target for cancer immunotherapy. Herein, we designed and synthesized a series of novel (pyridazine-3-yl)pyrimidine-2,4(1H,3H)-dione derivatives as CD73 inhibitors. These compounds exhibited remarkable inhibitory activity against CD73 in both enzymatic biochemical and cellular assays. Among them, compound 35j proved to be one of the most potent inhibitors and an uncompetitive inhibitor with no obvious cytotoxicity. This compound showed high metabolic stability in rat liver microsomes and favorable pharmacokinetic profiles in rats (T1/2 = 3.37 h, F = 50.24%). Importantly, orally administered 35j significantly inhibited tumor growth in the triple-negative breast cancer 4T1 mouse model (TGI = 73.6%, 50 mg/kg). Immunoassays suggested that 35j remarkably increased the infiltration of positive immune cells, thereby reinvigorating antitumor immunity. These results demonstrate that 35j is a potent CD73 inhibitor worthy of further development.

Targeting suppression of AKT activation boosts chemosensitivity of hepatocarcinoma cells via regulation of inflammation and metastasis: Functional protection of Rehmapicroside

Hepatocellular carcinoma (HCC) is the most common malignant tumors with poor prognosis and few effective therapeutic strategies. Although cisplatin (cDDP) is the first-line chemotherapy for HCC, its application has been limited due to drug resistance and side effects. Rehmapicroside (Reh) is a major active principle of the root of Radix Rehmanniae that has anti-tumor effects. In the present study, we uncovered the role of Reh in modulating chemosensitivity of cDDP in HCC. We found that combinational treatments of Reh and cDDP significantly reduced the cell proliferation of HCC cells at relatively lower concentrations for each drug. Cell cycle arrest in G2/M phase was markedly induced in HCC cells co-treated with Reh and cDDP compared with cDDP alone group. In addition, Reh dramatically enhanced the capacity of cDDP to induce apoptosis in HCC cells through increasing Caspase-3 cleavage. Co-treatment with Reh and cDDP effectively suppressed tumor growth in xenograft mouse models of HCC without adverse effects. Moreover, migration and invasion of HCC cells were significantly restrained by combinational treatments of Reh and cDDP. Mechanistically, tripartite motif protein 21-phosphatidylinositol 3-kinase/protein kinase B (TRIM21-PI3K/AKT) signaling pathway was considerably impeded in HCC cells and tumor tissues by Reh and cDDPco-treatment. Notably, we found that constitutive activation of AKT almost completely abrogated the capacity of Reh plus cDDP to inhibit cell proliferation, migration, and invasion. Collectively, our results demonstrated that combinational therapy of Reh and cDDP may be a novel and effective therapeutic strategy for HCC treatment.

Silmitasertib in Combination With Cabozantinib Impairs Liver Cancer Cell Cycle Progression, Induces Apoptosis, and Delays Tumor Growth in a Preclinical Model.

The rising incidence of hepatocellular carcinoma (HCC) is a global problem. Several approved treatments, including immune therapy and multi-tyrosine kinase inhibitors, are used for treatment, although the results are not optimum. There is an unmet need to develop highly effective chemotherapies for HCC. Targeting multiple pathways to attack cancer cells is beneficial. Cabozantinib is an orally available bioactive multikinase inhibitor and has a modest effect on HCC treatment. Silmitasertib is an orally bioavailable, potent CK2 inhibitor with a direct role in DNA damage repair and is in clinical trials for other cancers. In this study, we planned to repurpose these existing drugs on HCC treatment. We observed a stronger antiproliferative effect of these two combined drugs on HCC cells generated from different etiologies as compared to the single treatment. Global RNA-seq analyses revealed a decrease in the expression of G2/M cell cycle transition genes in HCC cells following combination treatment, suggesting G2 phase cell arrest. We observed G2/M cell cycle phase arrest in HCC cells upon combination treatment compared to the single-treated or vehicle-treated control cells. The downregulation of CCNA2 and CDC25C following combination therapy further supported the observation. Subsequent analyses demonstrated that combination treatment inhibited 70 kDa ribosomal protein S6 kinase (p70S6K) phosphorylation, and increased Bim expression. Apoptosis of HCC cells were accompanied by increased poly (ADP-ribose) polymerase cleavage and caspase-9 activation. Next, we observed that a combination therapy significantly delayed the progression of HCC xenograft growth as compared to vehicle control. Together, our results suggested combining cabozantinib and silmitasertib would be a promising treatment option for HCC.

A Novel Pan-RAS Inhibitor with a Unique Mechanism of Action Blocks Tumor Growth in Mouse Models of GI Cancer.

ADT-007 has unique pharmacological properties with distinct advantages over other RAS inhibitors by circumventing resistance and activating antitumor immunity. ADT-007 prodrugs and analogs with oral bioavailability warrant further development for RAS-driven cancers.

Optimized Fabrication of Dendritic Mesoporous Silica Nanoparticles as Efficient Delivery System for Cancer Immunotherapy.

In the past decade, cancer immunotherapy has revolutionized the field of oncology. Major immunotherapy approaches such as immune checkpoint inhibitors, cancer vaccines, adoptive cell therapy, cytokines, and immunomodulators have shown great promise in preclinical and clinical settings. Among them, immunomodulatory agents including cancer vaccines are particularly appealing; however, they face limitations, notably the absence of efficient and precise targeted delivery of immune-modulatory agents to specific immune cells and the potential for off-target toxicity. Nanomaterials can play a pivotal role in addressing targeting and other challenges in cancer immunotherapy. Dendritic mesoporous silica nanoparticles (DMSNs) can enhance the efficacy of cancer vaccines by enhancing the effective loading of immune modulatory agents owing to their tunable pore sizes. In this work, an emulsion-based method is optimized to customize the pore size of DMSNs and loaded DMSNs with ovalbumin (OVA) and cytosine-phosphate-guanine (CpG) oligodeoxynucleotides (CpG-OVA-DMSNs). The immunotherapeutic effect of DMSNs is achieved through controlled chemical release of OVA and CpG in antigen-presenting cells (APCs). The results demonstrated that CpG-OVA-DMSNs efficiently activated the immune response in APCs and reduced tumor growth in the murine B16-OVA tumor model.

An Exogenous Ketone Ester Slows Tumor Progression in Murine Breast and Renal Cancer Models.

Ketone esters (KEs) exhibit promise as anti-cancer agents but their impact on spontaneous metastases remains poorly understood. Although consumption of a ketogenic diet (KD) that is low in carbohydrates and high in fats can lead to KE production in vivo, the restrictive composition of KDs may diminish adherence in cancer patients. We investigated the effects of an exogenous ketone ester-supplemented (eKET), carbohydrate-replete diet on tumor growth, metastasis, and underlying mechanisms in orthotopic models of metastatic breast (4T1-Luc) and renal (Renca-Luc) carcinomas. Mice were randomized to diet after tumor challenge. Administration of KEs did not alter tumor cell growth in vitro. However, in mice, our eKET diet increased circulating β-hydroxybutyrate and inhibited primary tumor growth and lung metastasis in both models. Body composition analysis illustrated the overall safety of eKET diet use, although it was associated with a loss of fat mass in mice with renal tumors. Immunogenetic profiling revealed divergent intratumoral eKET-related changes by tumor type. In mammary tumors, Wnt and TGFβ pathways were downregulated, whereas in renal tumors, genes related to hypoxia and DNA damage repair were downregulated. Thus, our eKET diet exerts potent antitumor and antimetastatic effects in both breast and renal cancer models, albeit with different modes of action and physiologic effects. Its potential as an adjuvant dietary approach for patients with diverse cancer types should be explored further.

Inhibition of O-GlcNAc transferase activates type I interferon-dependent antitumor immunity by bridging cGAS-STING pathway.

The O-GlcNAc transferase (OGT) is an essential enzyme that mediates protein O-GlcNAcylation, a unique form of posttranslational modification of many nuclear and cytosolic proteins. Recent studies observed increased OGT and O-GlcNAcylation levels in a broad range of human cancer tissues compared to adjacent normal tissues, indicating a universal effect of OGT in promoting tumorigenesis. Here, we show that OGT is essential for tumor growth in immunocompetent mice by repressing the cyclic GMP-AMP synthase (cGAS)-dependent DNA sensing pathway. We found that deletion of OGT (Ogt-/-) caused a marked reduction in tumor growth in both syngeneic mice tumor models and a genetic mice colorectal cancer (CRC) model induced by mutation of the Apc gene (Apcmin). Pharmacological inhibition or genetic deletion of OGT induced a robust genomic instability (GIN), leading to cGAS-dependent production of the type I interferon (IFN-I) and IFN-stimulated genes (ISGs). As a result, deletion of Cgas or Sting from Ogt-/- cancer cells restored tumor growth, and this correlated with impaired CD8+ T-cell-mediated antitumor immunity. Mechanistically, we found that OGT-dependent cleavage of host cell factor C1 (HCF-1) is required for the avoidance of GIN and IFN-I production in tumors. In summary, our results identify OGT-mediated genomic stability and activate cGAS-STING pathway as an important tumor-cell-intrinsic mechanism to repress antitumor immunity.

An Adenosine Analogue Library Reveals Insights into Active Sites of Protein Arginine Methyltransferases and Enables the Discovery of a Selective PRMT4 Inhibitor.

Protein arginine methyltransferases (PRMTs) represent promising drug targets. However, the lack of isoform-selective chemical probes poses a significant hurdle in deciphering their biological roles. To address this issue, we devised a library of 100 diverse adenosine analogues, enabling a detailed exploration of the active site of PRMTs. Despite their close homology, our analysis unveiled specific chemical trends unique to the individual members. Notably, compound YD1130 demonstrated over 1000-fold selectivity for PRMT4 (IC50 < 0.5 nM) over a panel of 38 methyltransferases, including the other PRMTs. Its prodrug YD1342 exhibited potent inhibition on cellular substrate methylation, breast cancer cell colony formation, and tumor growth in the animal model, surpassing or matching known PRMT4-specific inhibitors. In summary, our focused library not only illuminates the intricate active sites of PRMTs to facilitate the discovery of highly potent and isoform-selective probes but also offers a versatile blueprint for identifying chemical probes for other methyltransferases.

Enhanced anti-tumor efficacy of electroporation (EP)-mediated DNA vaccine boosted by allogeneic lymphocytes in pre-established tumor models

BackgroundTumor-reactive T cells play a crucial role in anti-tumor responses, but T cells induced by DNA vaccination are time-consuming processes and exhibit limited anti-tumor efficacy. Therefore, we evaluated the anti-tumor effectiveness of reactive T cells elicited by electroporation (EP)-mediated DNA vaccine targeting epidermal growth factor receptor variant III (pEGFRvIII plasmid), in conjunction with adoptive cell therapy (ACT), involving the transfer of lymphocytes from a pEGFRvIII EP-vaccinated healthy donor.MethodsThe validation of the established pEGFRvIII plasmid and EGFRvIII-positive cell model was confirmed through immunofluorescence and western blot analysis. Flow cytometry and cytotoxicity assays were performed to evaluate the functionality of antigen-specific reactive T cells induced by EP-mediated pEGFRvIII vaccines, ACT, or their combination. The anti-tumor effectiveness of EP-mediated pEGFRvIII vaccines alone or combined with ACT was evaluated in the B16F10-EGFRvIII tumor model.ResultsEP-mediated pEGFRvIII vaccines elicited serum antibodies and a robust cellular immune response in both healthy and tumor-bearing mice. However, this response only marginally inhibited early-stage tumor growth in established tumor models. EP-mediated pEGFRvIII vaccination followed by adoptive transfer of lymphocytes from vaccinated healthy donors led to notable anti-tumor efficacy, attributed to the synergistic action of antigen-specific CD4+ Th1 cells supplemented by ACT and antigen-specific CD8+ T cells elicited by the EP-mediated DNA vaccination.ConclusionsOur preclinical studies results demonstrate an enhanced anti-tumor efficacy of EP-mediated DNA vaccination boosted with adoptively transferred, vaccinated healthy donor-derived allogeneic lymphocytes.

Changes in electrical parameters of the heart in an experimental model of malignant tumor growth during of hyperthyroidism

Experimental and clinical studies demonstrate the possibility of modulating the development of malignant tumors in thyroid imbalance, in particular hyperthyroidism, which negatively affects the electrophysiology of the heart. In an experimental model of tumor growth during of hyperthyroidism, activation of the tumor was shown.Aim: To study electrophysiological parameters of the mouse heart at the initial stages of transplantable tumor growth during of hyperthyroidism.Material and Methods. In female mice of the C57BL/6 line (n = 20) was created a model of melanoma B16/F10 growth during of hyperthyroidism, which was induced by daily intraperitoneal administration of liothyronine sodium (T3) for a long time and confirmed by determining the content of thyroid-stimulating hormone and triiodothyronine in the blood using the radioimmune method. On the 5th day of T3 administration, the melanoma was transplanted. ECG was recorded non-invasively (ecgTUN- NEL, ecgAVG software, emka TECHNOLOGIES, France) on the 1st and 3rd days of T3 administration, in groups with a tumor – on the 6th day after its transplantation.Results. Pathological changes were revealed: in the group with hyperthyroidism – rhythm irregularity, decrease the amplitude of P and T below the isoline, widening of the QRS, on the 3rd day – the death of 1 mouse was noted due to large-focal myocardial infarction; in the group with melanoma – only sinus arrhythmia and decreased heart rate; in the group with a combination of pathologies – an almost normal ECG, with the exception of an increase in P amplitude and a slight increase in QRS.Conclusion. Already in the early stages of hyperthyroidism or tumor growth, there was a violation of myocardial depolarization/ repolarization processes, capable of causing even death of the animal. In case of comorbidity, the majority of ECG parameters normalized, indicating the inclusion of compensatory mechanisms in the interaction of pathologies. The results demonstrate the need for a deeper study of the mechanisms of interaction of several simultaneously existing pathologies in the body.

Branched oncolytic peptides target HSPGs, inhibit metastasis, and trigger the release of molecular determinants of immunogenic cell death in pancreatic cancer.

Immunogenic cell death (ICD) can be exploited to treat non-immunoreactive tumors that do not respond to current standard and innovative therapies. Not all chemotherapeutics trigger ICD, among those that do exert this effect, there are anthracyclines, irinotecan, some platinum derivatives and oncolytic peptides. We studied two new branched oncolytic peptides, BOP7 and BOP9 that proved to elicit the release of damage-associated molecular patterns DAMPS, mediators of ICD, in pancreatic cancer cells. The two BOPs selectively bound and killed tumor cells, particularly PANC-1 and Mia PaCa-2, but not cells of non-tumor origin such as RAW 264.7, CHO-K1 and pgsA-745. The cancer selectivity of the two BOPs may be attributed to their repeated cationic sequences, which enable multivalent binding to heparan sulfate glycosaminoglycans (HSPGs), bearing multiple anionic sulfation patterns on cancer cells. This interaction of BOPs with HSPGs not only fosters an anti-metastatic effect in vitro, as demonstrated by reduced adhesion and migration of PANC-1 cancer cells, but also shows promising tumor-specific cytotoxicity and low hemolytic activity. Remarkably, the cytotoxicity induced by BOPs triggers the release of DAMPs, particularly HMGB1, IFN-β and ATP, by dying cells, persisting longer than the cytotoxicity of conventional chemotherapeutic agents such as irinotecan and daunorubicin. An in vivo assay in nude mice showed an encouraging 20% inhibition of tumor grafting and growth in a pancreatic cancer model by BOP9.

Gene therapy for diffuse pleural mesotheliomas in preclinical models by concurrent expression of NF2 and SuperHippo

Diffuse pleural mesothelioma (DPM) is a lethal cancer with a poor prognosis and limited treatment options. The Hippo signaling pathway genes, such as NF2 and LATS1/2, are frequently mutated in DPM, indicating a tumor suppressor role in the development of DPM. Here, we show that in DPM cell lines lacking NF2 and in mice with a conditional Nf2 knockout, downregulation of WWC proteins, another family of Hippo pathway regulators, accelerates DPM progression. Conversely, the expression of SuperHippo, a WWC-derived minigene, effectively enhances Hippo signaling and suppresses DPM development. Moreover, the adeno-associated virus serotype 6 (AAV6) has been engineered to deliver both NF2 and SuperHippo genes into mesothelial cells, which substantially impedes tumor growth in xenograft and genetic DPM models and prolongs the median survival of mice. These findings serve as a proof of concept for the potential use of gene therapy targeting the Hippo pathway to treat DPM.

A herbal pair of Scutellaria barbata D. Don and Scleromitrion diffusum (Willd.) R.J. Wang induced ferroptosis in ovarian cancer A2780 cells via inducing heme catabolism and ferritinophagy

ObjectiveDespite the combination of Scutellaria barbata D. Don and Scleromitrion diffusum (Willd.) R.J. Wang (SB-SD) being a recognized Chinese medicinal herbal pair that is commonly used in the treatment of ovarian cancer, there is a poor understanding of their pharmacological mechanisms. This study examines the antitumor properties and potential mechanisms of SB-SD on human ovarian cancer A2780 cells through a multi-omics approach, establishing a pharmacological basis for clinical utilization. MethodsA range of mass ratios and reagents were used in the hot reflux extraction of SB-SD. The inhibitory effect of the SB-SD extracts on A2780 cell proliferation was assessed using the cell-counting kit 8 assay. A zebrafish tumor implantation model was used to evaluate the effects of SB-SD extracts on tumor growth and metastasis in vivo. Transcriptomics and proteomics were used to investigate alterations in biological pathways in A2780 cells after treatment with different concentrations of SB-SD extract. Cell cycle, cell apoptosis, intracellular free iron concentration, intracellular reactive oxygen species (ROS) concentration, malondialdehyde (MDA), and mitochondrial membrane potential were measured. Real-time quantitative reverse transcription polymerase chain reaction and Western blotting were utilized to investigate the effects of heme catabolism and ferritinophagy on ferroptosis induced by SB-SD extract in A2780 cells. ResultsThe 70% ethanol extract of SB-SD (a mass ratio of 4:1) inhibited A2780 cell proliferation significantly with a half maximal inhibitory concentration of 660 μg/mL in a concentration- and time-dependent manner. Moreover, it effectively suppressed tumor growth and metastasis in a zebrafish tumor implantation model. SB-SD extract induced the accumulation of free iron, ROS, MDA, and mitochondrial damage in A2780 cells. The mechanisms might involve the upregulated expression of ferritinophagy-related genes microtubule-associated protein 1 light chain 3, autophagy-related gene 5, and nuclear receptor coactivator 4. ConclusionsSB-SD extract effectively inhibited the development of ovarian cancer both in vitro and in vivo. Its mechanism of action involved inducing ferroptosis by facilitating heme catabolism and ferritinophagy. This herbal pair holds promise as a potential therapeutic option for ovarian cancer treatment and may be utilized in combination with routine treatment to improve the treatment outcomes of ovarian cancer patients.

Structure‐based design of antibodies targeting the EBNA1 DNA‐binding domain to block Epstein–Barr virus latent infection and tumor growth

AbstractThe Epstein–Barr virus (EBV) nuclear antigen 1 (EBNA1) is critically involved in maintaining episomes during latent infection and promoting tumorigenesis. The development of an epitope‐specific monoclonal antibody (mAb) for EBNA1 holds great promise due to its high affinity and specificity, offering a new and innovative approach for the treatment of EBV‐related diseases. In this proof‐of‐concept study, we employed a structure‐based design strategy to create three unique immunogens specifically targeting the DNA binding state of the EBNA1 DBD. By immunizing mice, we successfully generated a mAb, named 5E2‐12, which selectively targets the DNA binding interface of EBNA1. The 5E2‐12 mAb effectively disrupts the interaction between EBNA1 and DNA binding, resulting in reduced proliferation of EBV‐positive cells and inhibition of xenograft tumor growth in both cellular assays and mouse tumor models. These findings open up new avenues for the development of innovative biological macromolecular drugs that specifically target EBNA1 and provide potential for clinical therapy options for early‐stage EBV‐positive tumors. The epitope‐specific mAb approach demonstrates novelty and innovation in tackling EBV‐related diseases and may have broad implications for precision medicine strategies in the field of viral‐associated cancers.

A size-switchable nanocluster remodels the immunosuppressive microenvironment of tumor and tumor-draining lymph nodes for improved cancer immunotherapy

Remodeling the immunosuppressive tumor microenvironment (TME) by immunomodulators has been well studied in the past years. However, strategies that enable concurrent modulation of both the immunosuppressive TME and tumor-draining lymph nodes (TDLNs) are still in the infancy. Here, we report a pH-sensitive size-switchable nanocluster, SPN-R848, to achieve simultaneous accumulation in tumor and TDLNs for immune activation. SPN-R848 with original size around 150 nm was formed by self-assembly of resiquimod (R848)-conjugated polyamidoamine (PAMAM) derivative, which could disintegrate into its small constituents (～ 8 nm) upon exposure to tumor acidity. The size reduction not only enhanced their accumulation and perfusion in the primary tumor, but promoted their transport and distribution in TDLNs. Accordingly, SPN-R848 remarkably remodeled the immunosuppressive TME by polarizing M2 to M1 macrophages and activated dendritic cells (DCs) in TDLNs, which synergistically facilitated the production and stimulation of cytotoxic T cells, and inhibited tumor growth in breast cancer and melanoma mouse models. Our study suggests that co-activation of immune microenvironments in both tumor and TDLNs may represent a promising direction to elicit strong antitumor immunity.

Synergistic effects of ω-3 polyunsaturated fatty acid supplementation and programmed cell death protein 1 blockade on tumor growth and immune modulation in a xenograft model of esophageal cancer

Synergistic effects of ω-3 polyunsaturated fatty acid supplementation and programmed cell death protein 1 blockade on tumor growth and immune modulation in a xenograft model of esophageal cancer

A novel indole derivative, 2-{3-[1-(benzylsulfonyl)piperidin-4-yl]-2-methyl-1H-indol-1-yl}-1-(pyrrolidin-1-yl)ethenone, suppresses hedgehog signaling and drug-resistant tumor growth.

The Hedgehog (Hh) signaling pathway plays important roles in various physiological functions. Several malignancies, such as basal cell carcinoma (BCC) and medulloblastoma (MB), have been linked to the aberrant activation of Hh signaling. Although therapeutic drugs have been developed to inhibit Hh pathway-dependent cancer growth, drug resistance remains a major obstacle in cancer treatment. Here, we show that the newly identified, 2-{3-[1-(benzylsulfonyl)-1,2,3,6-tetrahydropyridin-4-yl]-2-methyl-1H-indol-1-yl}-1-(pyrrolidin-1-yl)ethenone analog (LKD1214) exhibits comparable potency to vismodegib in suppressing the Hh pathway activation. LKD1214 represses Smoothened (SMO) activity by blocking its ciliary translocation. Interestingly, we also identified that it has a distinctive binding interface with SMO compared with other SMO-regulating chemicals. Notably, it maintains an inhibitory activity against the SmoD477H mutant, as observed in a patient with vismodegib-resistant BCC. Furthermore, LKD1214 inhibits tumor growth in the mouse model of MB. Collectively, these findings suggest that LKD1214 has the therapeutic potential to overcome drug-resistance in Hh-dependent cancers.

Assembly of 2′,3′-Cyclic guanosine Monophosphate-Adenosine monophosphate and their spontaneous intracellular disassembly for enhanced antitumor immunity via natural STING pathway activation

The stimulator of interferon genes (STING) pathway plays an important role in remodeling the immunosuppressive tumor microenvironment (TME). Cyclic dinucleotides (CDNs), the natural ligands of STING, activate innate immunity to enhance tumor immunogenicity. However, the anionic properties of CDNs result in poor membrane permeability, while their rapid metabolism by enzymes hinders the efficient targeting and activation of STING in vitro and in vivo. To improve the bioavailability and antitumor immunity of CDNs, we designed a hydrogen-bonding-based supramolecular approach for 2′,3′-cyclic guanosine monophosphate (GMP)-adenosine monophosphate (AMP) (cGAMP). Leveraging the synthetic molecules cytosine-uracil-hexane (CUH), we formulated supramolecular micelles of cGAMP via specific hydrogen bonds in aqueous solutions. Micelles comprising the CUH-cGAMP complex enhanced the biological efficacy of cGAMP by increasing its stability, thereby prolonging the activation of STING-mediated innate and adaptive immunity. We demonstrated that CUH-cGAMP stands as a promising candidate for immunotherapy, exhibiting significant inhibition of tumor growth in a CT26 syngeneic mouse model.

Fasting-mimicking diet potentiates anti-tumor effects of CDK4/6 inhibitors against breast cancer by suppressing NRAS- and IGF1-mediated mTORC1 signaling

AimsAcquired resistance to cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) frequently emerges, and CDK4/6i-containing therapies in triple-negative breast cancer (TNBC) remain to be determined. MethodsRNA-sequencing, cell viability analysis, immunoblotting, siRNA transfection et al. were used to investigate and verify the resistance mechanism. BALB/c nude mice xenograft models and spontaneous MMTV-PyMT models were used to explore in vivo efficacy. ResultsThe mTOR pathway was activated in acquired CDK4/6i-resistant cells and inhibition of mTORC1 restored the sensitivity. While fasting-mimicking diet (FMD) enhances the activity of anticancer agents by inhibiting the mTORC1 signaling, we assessed FMD and found that FMD restored the sensitivity of CDK4/6i-resistant cells to abemaciclib and potentiated the anti-tumor activity of CDK4/6i in TNBC. The anti-tumor effects of FMD and/or CDK4/6i were accompanied by the downregulation of S6 phosphorylation. FMD cooperated with CDK4/6i to suppress the levels of IGF1 and RAS. The combination of FMD and abemaciclib also led to a potent inhibition of tumor growth in spontaneous transgenic MMTV-PyMT mouse models. ConclusionsOur data demonstrate that FMD overcomes resistance and potentiates the anti-tumor effect of CDK4/6i by inhibiting mTORC1 signaling via lowering the levels of IGF1 and RAS, providing the rationale for clinical investigation of a potential FMD-CDK4/6i strategy in breast cancer.