Re-expression of epigenetically silenced PTPRR by histone acetylation sensitizes RAS-mutant lung adenocarcinoma to SHP2 inhibition.

Silenced protein tyrosine phosphatase receptor type R (PTPRR) participates in mitogen-activated protein kinase (MAPK) signaling cascades during the genesis and development of tumors. Rat sarcoma virus (Ras) genes are frequently mutated in lung adenocarcinoma, thereby resulting in hyperactivation of downstream MAPK signaling. However, the molecular mechanism manipulating the regulation and function of PTPRR in RAS-mutant lung adenocarcinoma is not known. Patient records collected from the Cancer Genome Atlas and Gene Expression Omnibus showed that silenced PTPRR was positively correlated with the prognosis. Exogenous expression of PTPRR suppressed the proliferation and migration of lung cancer cells. PTPRR expression and Src homology 2 containing protein tyrosine phosphatase 2 (SHP2) inhibition acted synergistically to control ERK1/2 phosphorylation in RAS-driven lung cancer cells. Chromatin immunoprecipitation assay revealed that HDAC inhibition induced enriched histone acetylation in the promoter region of PTPRR and recovered PTPRR transcription. The combination of the HDAC inhibitor SAHA and SHP2 inhibitor SHP099 suppressed the progression of lung cancer markedly in vitro and in vivo. Therefore, we revealed the epigenetic silencing mechanism of PTPRR and demonstrated that combination therapy targeting HDAC and SHP2 might represent a novel strategy to treat RAS-mutant lung cancer.

SHMT2 Promotes Gastric Cancer Development through Regulation of HIF1α/VEGF/STAT3 Signaling.

The metabolic enzymes involved in one-carbon metabolism are closely associated with tumor progression and could be potential targets for cancer therapy. Recent studies showed that serine hydroxymethyltransferase 2 (SHMT2), a crucial enzyme in the one-carbon metabolic pathway, plays a key role in tumor proliferation and development. However, the precise role and function of SHMT2 in gastric cancer (GC) remain poorly understood. In this study, we presented evidence that SHMT2 was necessary for hypoxia-inducible factor-1α (HIF1α) stability and contributed to GC cells' hypoxic adaptation. The analysis of datasets retrieved from The Cancer Genome Atlas and the experimentation with human cell lines revealed a marked increase in SHMT2 expression in GC. The SHMT2 knockdown in MGC803, SGC7901, and HGC27 cell lines inhibited cell proliferation, colony formation, invasion, and migration. Notably, SHMT2 depletion disrupted redox homeostasis and caused glycolytic function loss in GC cells under hypoxic circumstances. Mechanistically, we discovered SHMT2 modulated HIF1α stability, which acted as a master regulator of hypoxia-inducible genes under hypoxic conditions. This, in turn, regulated the downstream VEGF and STAT3 pathways. The in vivo xenograft experiments showed that SHMT2 knockdown markedly reduced GC growth. Our results elucidate the novel function of SHMT2 in stabilizing HIF1α under hypoxic conditions, thus providing a potential therapeutic strategy for GC treatment.

(+)-Isocryptotanshinone derivatives and its simplified analogs as STAT3 signaling pathway inhibitors.

Isocryptotanshinone (ICTS), a natural product with potential signal transducer and activator of transcription-3 (STAT3) signaling pathway inhibitory activity, shows significant inhibitory activity against several tumors. In this study, a series of ICTS derivatives and simplified analogs containing a 1, 4-naphthoquinone core was designed, synthesized, and evaluated. The results demonstrated that most target compounds were potent STAT3 signaling pathway inhibitors based on their mechanism of inhibition of STAT3 phosphorylation. Moreover, based on the obtained data, the structure-activity relationship (SAR) was rationally deduced. Simultaneously, molecular docking of the compound 16r suggested its possible interaction mode with STAT3. To further verify anticancer activity, all target compounds were tested using HCT116, HepG2, MCF-7, A549, and U251 cell lines. Interestingly, compared with different tumor cell lines, the HCT-116 cell line was determined to be the most sensitive. Furthermore, compounds 21e, 16r, 28a, and 16e showed a dose-dependent inhibition of the growth of HCT116 cells. Thus, the SAR of ICTS derivatives and its simplified analogs was determined, and some of them were discovered to be potential anticancer candidates owing to their ability to inhibit the STAT3 signaling pathway.

Secreted HSP90α-LRP1 Signaling Promotes Tumor Metastasis and Chemoresistance in Pancreatic Cancer.

The extracellular heat shock protein 90α (eHSP90α) has been reported to promote cancer cell motility. However, whether pancreatic cancer (PC) cells expressed membrane-bound or secreted HSP90α, as well as its underlying mechanism for PC progression, were still unclear. Our study demonstrated that the amounts of secreted HSP90α proteins were discrepant in multiple PC cells. In addition, highly invasive Capan-2 cells have a higher level of secreted HSP90α compared with those of less invasive PL45 cells. The conditioned medium of Capan-2 cells or recombinant HSP90α treatment stimulated the migration and invasion of PC cells, which could be prevented with a neutralizing anti-HSP90α antibody. Furthermore, secreted HSP90α promoted elements of epithelial-mesenchymal transition in PL45 cells, including increases in vimentin and Snail expressions, decreases in E-cadherin expression, and changes in cell shape towards a mesenchymal phenotype, but these phenomena were reversed by the anti-HSP90α antibody in Capan-2 cells. In addition, high levels of low-density lipoprotein receptor-related protein 1 (LRP1) were associated with worsened patient survival in pancreatic adenocarcinoma. We demonstrated LRP1 as a receptor of eHSP90α for its stimulatory role in metastasis, by activating the AKT pathway. In addition, silencing LRP1 enhanced the chemosensitivity to gemcitabine and doxorubicin in Capan-2 cells. Therefore, our study indicated that blocking secreted HSP90α underlies an aspect of metastasis and chemoresistance in PC.

Chlorogenic Acid Prevents UVA-Induced Skin Photoaging through Regulating Collagen Metabolism and Apoptosis in Human Dermal Fibroblasts.

Skin aging is categorized as chronological aging and photo-aging that affected by intrinsic and extrinsic factors. The present study aimed to investigate the anti-aging ability and its underlying mechanism of chlorogenic acid (CGA) on human dermal fibroblasts (HDFs). In this study, CGA specifically up-regulated collagen I (Col1) mRNA and protein expressions and increased the collagen secretion in the supernatant of HDFs without affecting the cell viability, the latter was also demonstrated in BioMAP HDF3CGF system. Under ultraviolet A (UVA)-induced photoaging, CGA regulated collagen metabolism by increasing Col1 expression and decreasing matrix metalloproteinase 1 (MMP1) and MMP3 levels in UVA-irradiated HDFs. The activation of transforming growth factor-ß (TGF-ß)-mediated Smad2/3 molecules, which is crucial in Col1 synthesis, was suppressed by UVA irradiation and but enhanced at the presence of CGA. In addition, CGA reduced the accumulation of UVA-induced reactive oxygen species (ROS), attenuated the DNA damage and promoted cell repair, resulting in reducing the apoptosis of UVA-irradiated HDFs. In conclusion, our study, for the first time, demonstrate that CGA has protective effects during skin photoaging, especially triggered by UVA-irradiation, and provide rationales for further investigation of CGA being used to prevent or treat skin aging.

Chaperone-mediated autophagy degradation of IGF-1Rß induced by NVP-AUY922 in pancreatic cancer.

Enhancement of insulin-like growth factor 1 receptor (IGF-IR) degradation by heat shock protein 90 (HSP90) inhibitor is a potential antitumor therapeutic strategy. However, very little is known about how IGF-IR protein levels are degraded by HSP90 inhibitors in pancreatic cancer (PC). We found that the HSP90α inhibitor NVP-AUY922 (922) effectively downregulated and destabilized the IGF-1Rß protein, substantially reduced the levels of downstream signaling molecules (p-AKT, AKT and p-ERK1/2), and resulted in growth inhibition and apoptosis in IGF-1Rß-overexpressing PC cells. Preincubation with a proteasome or lysosome inhibitor (MG132, 3 MA or CQ) mainly led to IGF-1Rß degradation via the lysosome degradation pathway, rather than the proteasome-dependent pathway, after PC cells were treated with 922 for 24 h. These results might be associated with the inhibition of pancreatic cellular chymotrypsin-peptidase activity by 922 for 24 h. Interestingly, 922 induced autophagic flux by increasing LC3II expression and puncta formation. However, knockdown of the crucial autophagy component AGT5 and the chemical inhibitor 3 MA-blocked 922-induced autophagy did not abrogate 922-triggered IGF-1Rß degradation. Furthermore, 922 could enhance chaperone-mediated autophagy (CMA) activity and promote the association between HSP/HSC70 and IGF-1Rß or LAMP2A in coimmunoprecipitation and immunofluorescence analyses. Silencing of LAMP2A to inhibit CMA activity reversed 922-induced IGF-1Rß degradation, suggesting that IGF-1Rß degradation by 922 was partially dependent on the CMA pathway rather than macroautophagy. This finding is mirrored by the identification of the KFERQ-like motif in IGF-1Rß. These observations support the potential application of 922 for IGF-1Rß-overexpressing PC therapy and first identify the role of the CMA pathway in IGF-1Rß degradation by an HSP90 inhibitor.

KLF7 promotes polyamine biosynthesis and glioma development through transcriptionally activating ASL.

Krüppel-like factors (KLFs) are zinc-finger transcriptional factors that regulate target gene expression. Recent studies have shown that KLFs play essential roles in cancer development, whereas the function of KLF7 in glioma remains unclear. In this study, we showed that KLF7 was up-regulated in glioma tissues and its expression was inversely correlated with the patients' survival. Functional experiments demonstrated that KLF7 promoted the proliferation, migration and tumorigenesis of glioma cells. Mechanistically, KLF7 transcriptionally activated argininosuccinate lyase (ASL), which was observed highly expressed in glioma tissues. The biosynthesis of polyamine, a urea cycle metabolite, was enhanced by KLF7 in glioma cells. In addition, ASL contributed to the growth of glioma cells triggered by KLF7. Our findings demonstrate KLF7 as an oncogene and link KLF7 to ASL-mediated polyamine metabolism in glioma.

Validating a Selective S1P1 Receptor Modulator Syl930 for Psoriasis Treatment.

Psoriasis is a chronic inflammatory skin disease characterized by red, scaly and raised plaques. Thus far, T-cell infiltration is one of the most prominent pathogenic triggers, however, the exact molecular mechanisms underlying psoriasis have not been clearly established. Sphingolipid sphingosine-1-phosphate (S1P) is a lysophospholipid regulator modulating a variety of immune cell trafficking via interactions with its cognate receptors, S1P1-5. Activation of S1P signaling has recently emerged as a novel therapeutic avenue for psoriasis treatment. Here, we test a newly developed selective S1P1 modulator, Syl930, in four different psoriasis animal models. Our data reveals that oral administration of Syl930 can induce strong anti-proliferative and anti-inflammatory effects. Specifically, Syl930 decreases the pathological thickening of back skin induced by sodium lauryl sulfate (SLS), inhibits the proliferation of basal cells in a vaginal epithelium model and increases the granular layer scales in a mouse tail assay. Moreover, Syl930 can ameliorate the parakeratosis and acanthosis as well as improve granular layer composition and decrease the thickening of epidermis in a propranolol-induced guinea pig psoriasis model. Therefore, we demonstrate that Syl930 is a promising candidate for psoriasis therapy in clinical.

Exploration of the Fluorescent Properties and the Modulated Activities against Sirtuin Fluorogenic Assays of Chromenone-Derived Natural Products.

Chromenone-derived natural products include chromones (flavone, isoflavone) and coumarins. Chromenone compounds not only exhibit impressive biological activities, but also are an important resource of experimentally used fluorophores, such as, 7-amino-4-methylcoumarin (AMC). Various chromenone compounds have reported to have weak fluorescence, and this has the potential to interfere with the measurements during AMC fluorogenic assays and result in non-robust assay readouts. Several flavones and isoflavones were found as SIRT1 activators, while fluorogenic sirtuin assays utilized AMC labelled peptides as the substrates. In this study we investigated whether the fluorescent properties of chromenone-derived natural products interrupt the measurement of SIRT1/2 modulated activities. We found that the reported SIRT1 activators: flavones were detected with the SIRT1 activation activity, but isoflavones were not detected with SIRT1 activation activity, and instead that they were found to be fluorogenic compounds. Another chromenone compound, osthole, exhibited a moderate SIRT2 inhibitory activity with an IC50 of 10 µM. In conclusion, the fluorescent properties of these chromenone compounds do affect the measurement of the sirtuin activities of both inhibitors and activators. However, if the possible fluorescence properties are mitigated in the assay readout, these fluorogenic assays enable the screening of activity modulators.

The Characteristics of Hepatic Gsα-cAMP Axis in HSHF Diet-Fed Obese Insulin Resistance Rats and Genetic Diabetic Mice.

Stimulatory G protein α-subunit (Gsα) mediated cAMP signal is required for elevated hepatic glucose production (HGP) in diabetic patients. However, it remains obscure of the exact characteristics of hepatic Gsα-cAMP signal axis (including Gsα, glucagon receptor, ß2-adrenergic receptor, cAMP, phosphoenolpyruvate carboxykinase and glucose-6-phosphatase) in insulin resistance (IR) and type 2 diabetes mellitus (T2DM). In current study, we investigated the changing characteristics of hepatic Gsα-cAMP signal axis and blood glucose in high-sugar-high-fat (HSHF)-diet-induced IR Wistar rats and db/db diabetic mice. As expected, the HSHF-diet rats were characterized by hyperinsulinemia, hyperglycemia and impaired glucose tolerance. According to a threshold (1.7) of homeostasis model assessment ratio (HOMA-R), the process of IR in HSHF-diet rats could be divided into slight and high IR stages, with the week-23 as the cut-off point. In early slight IR stage, key molecules expressions of hepatic Gsα-cAMP signal axis in HSHF-diet rats were up-regulated with significantly elevated fasting blood glucose (FBG) from 18 to 23 weeks. Unexpectedly, in high IR stage, hepatic Gsα-cAMP signal axis was recovered comparatively to that of normal chow-diet rats, and no significant differences in FBG levels were found. However, in diabetic db/db mice, up-regulation of hepatic Gsα-cAMP signal axis was responsible for its severely increased fasting hyperglycaemia. Our data revealed a positive correlation between hepatic Gsα-cAMP signal axis and FBG in slight IR stage of HSHF-diet rats and diabetic db/db mice. The current finding thus suggested hepatic Gsα-cAMP signal axis plays a central role in regulating of FBG during the developing and development of T2DM.

C15-methoxyphenylated 18-deoxy-herbimycin A analogues, their in vitro anticancer activity and heat shock protein 90 binding affinity.

Benzoquinone ansamycins are important leads for the discovery of novel inhibitors of heat shock protein 90 (Hsp90), a promising target of cancer chemotherapeutics. Intrinsic hepatotoxicity caused by the benzoquinone moiety appeared to be a serious limitation to the development of these compounds. To solve this problem by rational structure optimization, a short series of C18-deoxy analogues of herbimycin A were designed based on putative interactions between the compound and the protein. Chemical synthesis of the target molecules were attempted by following the established synthetic route to the natural product, but resulted in the isolation of four serendipitous C15 phenylated final products. In vitro antiproliferative activity and Hsp90 binding affinity of the compounds were determined, suggesting the C18-oxygen of herbimycin A is removable and bulky lipophilic groups can be accommodated at C15 without loss of activity.

Development and validation of high-throughput screening assays for poly(ADP-ribose) polymerase-2 inhibitors.

Poly(ADP-ribose) polymerase-1 and -2 (PARP1/2) are two key facilitators of DNA repair and are implicated in the pathogenesis of cancers and several chronic diseases. Inhibitors of PARP1/2 have shown powerful therapeutic effects in the treatment of cancer, cerebral ischemia, and inflammation. In addition, evidence from several studies suggests unique functions for PARP2 in genome surveillance, spermatogenesis, adipogenesis, and T cell development, and PARP2-specific inhibitors might have many other applications. To acquire PARP1/2 inhibitors, many high-throughput screening (HTS) assays for PARP1 inhibitors have been developed. However, detailed screening assays for PARP2 inhibitors have not been reported. Herein, three HTS assays for PARP2 inhibitors were developed and validated with reference inhibitors in each case. The results suggest that the HTS assays for PARP2 inhibitors using chemical quantification of NAD(+), biotin-based quantification of PAR, and ELISA quantification of PAR are sensitive, robust, and cost effective.

Discovery of Natural Ah Receptor Antagonists from Salvia miltiorrhiza Bunge and Synthesis of Analogs for Tumor Immunotherapy.

IDO/TDO/Kyn/AhR signaling plays a crucial role in regulating innate and adaptive immunity, and targeting Ah receptor (AhR) inhibition can potentially redirect immune cells toward an antitumoral phenotype. Therefore, AhR is an attractive drug target for novel small molecule cancer immunotherapies. In this study, natural products tanshinolic A-D (1-4), the first adducts composed of ortho-naphthoquinone-type tanshinone and phenolic acid featuring a unique 1,4-benzodioxan hemiacetal structure, were isolated and characterized from the roots of Salvia miltiorrhiza Bunge. Luciferase reporter gene assay revealed that these adducts exhibited significant AhR inhibitory activity. A linear strategy was developed to construct a cis-3,4-disubstituted 1,4-benzodioxan hemiacetal structure. Encouragingly, in both in vitro and in vivo experiments, (±)-13e demonstrated the ability to inhibit tumor cell proliferation, promote INF-γ secretion in CD8+ T cells, and inhibit PD-1/PD-L1 signal transduction, which could exert tumor inhibition properties by inhibiting AhR activity, positioning it as a promising candidate for tumor immunotherapy.

Honokiol prevents lung metastasis of triple-negative breast cancer by regulating polarization and recruitment of macrophages.

Metastasis is the leading cause of breast cancer-associated death. Lung metastasis commonly occurs in triple-negative breast cancer (TNBC) metastasis, worsening the TNBC prognosis. Considering their role in tumor progression and metastasis, tumor-associated macrophages (TAMs) are essential therapeutic targets in cancer therapy. Previous studies have demonstrated that honokiol inhibits tumor growth and progression. Here we assessed how honokiol inhibits lung metastasis of TNBC by regulating the polarization of macrophages. We found that honokiol decreased the expression of IL-13-triggered M2 markers like CD206, Arg1, and CCL2, preventing the invasion and migration ability of TNBC cells. The activation of signal transducer and activator of transcription STAT6 and STAT3 was significantly suppressed by honokiol in M2 polarized macrophages. Meanwhile, honokiol increased the expression of LPS/IFNγ-induced M1 markers such as CD11c, iNOS, and IL12 by promoting STAT1 phosphorylation. Besides, honokiol decreased both the ratio of M2/M1 macrophages and the expression of the IL-10/IL-12 gene in lung tissues, thereby inhibiting the proliferation and metastasis of murine breast cancer. Moreover, honokiol reduced the infiltration of macrophages to the lung tissue through the CCL2/CCR2 pathways. These results highlight the potential of honokiol in suppressing TNBC tumor progression and lung metastasis by regulating the polarization and recruitment of macrophages.

Chlorogenic Acid Induced Neuroblastoma Cells Differentiation via the ACAT1-TPK1-PDH Pathway.

BACKGROUND: Chlorogenic acid (CHA) has been shown to have substantial biological activities, including anti-inflammatory, antioxidant, and antitumor effects. However, the pharmacological role of CHA in neuroblastoma has not yet been assessed. Neuroblastoma is a type of cancer that develops in undifferentiated sympathetic ganglion cells. This study aims to assess the antitumor activity of CHA against neuroblastoma and reveal its mechanism of action in cell differentiation. METHODS: Be(2)-M17 and SH-SY5Y neuroblastoma cells were used to confirm the differentiation phenotype. Subcutaneous and orthotopic xenograft mouse models were also used to evaluate the antitumor activity of CHA. Seahorse assays and metabolomic analyses were further performed to investigate the roles of CHA and its target ACAT1 in mitochondrial metabolism. RESULTS: CHA induced the differentiation of Be(2)-M17 and SH-SY5Y neuroblastoma cells in vivo and in vitro. The knockdown of mitochondrial ACAT1, which was inhibited by CHA, also resulted in differentiation characteristics in vivo and in vitro. A metabolomic analysis revealed that thiamine metabolism was involved in the differentiation of neuroblastoma cells. CONCLUSIONS: These results provide evidence that CHA shows good antitumor activity against neuroblastoma via the induction of differentiation, by which the ACAT1-TPK1-PDH pathway is involved. CHA is a potential drug candidate for neuroblastoma therapy.

ACAT1 deficiency in myeloid cells promotes glioblastoma progression by enhancing the accumulation of myeloid-derived suppressor cells.

Glioblastoma (GBM) is a highly aggressive and lethal brain tumor with an immunosuppressive tumor microenvironment (TME). In this environment, myeloid cells, such as myeloid-derived suppressor cells (MDSCs), play a pivotal role in suppressing antitumor immunity. Lipometabolism is closely related to the function of myeloid cells. Here, our study reports that acetyl-CoA acetyltransferase 1 (ACAT1), the key enzyme of fatty acid oxidation (FAO) and ketogenesis, is significantly downregulated in the MDSCs infiltrated in GBM patients. To investigate the effects of ACAT1 on myeloid cells, we generated mice with myeloid-specific (LyzM-cre) depletion of ACAT1. The results show that these mice exhibited a remarkable accumulation of MDSCs and increased tumor progression both ectopically and orthotopically. The mechanism behind this effect is elevated secretion of C-X-C motif ligand 1 (CXCL1) of macrophages (Mφ). Overall, our findings demonstrate that ACAT1 could serve as a promising drug target for GBM by regulating the function of MDSCs in the TME.

Erratum: Author correction to "YPD-30, a prodrug of YPD-29B, is an oral small-molecule inhibitor targeting PD-L1 for the treatment of human cancer" [Acta Pharmaceutica Sinica B 12 (2022) 2845-2858].

[This corrects the article DOI: 10.1016/j.apsb.2022.02.031.].

S-72, a Novel Orally Available Tubulin Inhibitor, Overcomes Paclitaxel Resistance via Inactivation of the STING Pathway in Breast Cancer.

Microtubule-targeting agents are widely used as active anticancer drugs. However, drug resistance always emerges after their long-term use, especially in the case of paclitaxel, which is the cornerstone of all subtypes of breast cancer treatment. Hence, the development of novel agents to overcome this resistance is vital. This study reports on a novel, potent, and orally bioavailable tubulin inhibitor called S-72 and evaluated its preclinical efficacy in combating paclitaxel resistance in breast cancer and the molecular mechanisms behind it. We found that S-72 suppresses the proliferation, invasion and migration of paclitaxel-resistant breast cancer cells in vitro and displays desirable antitumor activities against xenografts in vivo. As a characterized tubulin inhibitor, S-72 typically inhibits tubulin polymerization and further triggers mitosis-phase cell cycle arrest and cell apoptosis, in addition to suppressing STAT3 signaling. Further studies showed that STING signaling is involved in paclitaxel resistance, and S-72 blocks STING activation in paclitaxel-resistant breast cancer cells. This effect further restores multipolar spindle formation and causes deadly chromosomal instability in cells. Our study offers a promising novel microtubule-destabilizing agent for paclitaxel-resistant breast cancer treatment as well as a potential strategy that can be used to improve paclitaxel sensitivity.

S1PR1 serves as a viable drug target against pulmonary fibrosis by increasing the integrity of the endothelial barrier of the lung.

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with unclear etiology and limited treatment options. The median survival time for IPF patients is approximately 2-3 years and there is no effective intervention to treat IPF other than lung transplantation. As important components of lung tissue, endothelial cells (ECs) are associated with pulmonary diseases. However, the role of endothelial dysfunction in pulmonary fibrosis (PF) is incompletely understood. Sphingosine-1-phosphate receptor 1 (S1PR1) is a G protein-coupled receptor highly expressed in lung ECs. Its expression is markedly reduced in patients with IPF. Herein, we generated an endothelial-conditional S1pr1 knockout mouse model which exhibited inflammation and fibrosis with or without bleomycin (BLM) challenge. Selective activation of S1PR1 with an S1PR1 agonist, IMMH002, exerted a potent therapeutic effect in mice with bleomycin-induced fibrosis by protecting the integrity of the endothelial barrier. These results suggest that S1PR1 might be a promising drug target for IPF therapy.

YPD-30, a prodrug of YPD-29B, is an oral small-molecule inhibitor targeting PD-L1 for the treatment of human cancer.

PD-1 and PD-L1 antibodies have brought about extraordinary clinical benefits for cancer patients, and their indications are expanding incessantly. Currently, most PD-1/PD-L1 agents are administered intravenously, which may be uncomfortable for some cancer patients. Herein, we develop a novel oral-delivered small molecular, YPD-29B, which specifically targets human PD-L1. Our data suggested that YPD-29B could potently and selectively block the interaction between PD-L1 and PD-1, but did not inhibit any other immune checkpoints. Mechanistically, YPD-29B induced human PD-L1 dimerization and internalization, which subsequently activated T lymphocytes and therefore overcomes immunity tolerance in vitro. YDP-29B was modified as the YPD-30 prodrug to improve druggability. Using humanized mice with human PD-1 xenografts of human PD-L1 knock-in mouse MC38 cancer cells, we demonstrated that YPD-30 exhibited significant antitumor activity and was well tolerated in vivo. Taken together, our results indicate that YPD-30 serves as a promising therapeutic candidate for anti-human PD-L1 cancer immunotherapy.