Abnormal methylation mediated upregulation of LINC00857 boosts malignant progression of lung adenocarcinoma by modulating the miR-486-5p/NEK2 axis.

LINC00857 is frequently dysregulated in varying cancers, which in turn exerts carcinogenic effects; however, its DNA methylation status in promoter region and molecular mechanisms underlying the progression of lung adenocarcinoma (LUAD) remain rarely understood. Through bioinformatics analysis, we examined the expression state and methylation site of LINC00857 in LUAD and further investigated the properties of LINC00857 as a competitive endogenous RNA in the cancer progression. The current study revealed that the overexpression of LINC00857 in LUAD tissue and cells was mainly caused by the hypomethylation of the promoter region. LINC00857 knockdown prominently reduced cell proliferation, impeded cell migration and invasion, and restrained lymph node metastasis, with enhancing radiosensitivity. The effects of LINC00857 on tumor growth were also investigated in nude mice models. Subsequently, the downstream factors, miR-486-5p and NEK2, were screened, and the putative regulatory axis was examined. Overall, the regulatory effect of methylation-mediated LINC00857 overexpression on miR-486-5p/NEK2 axis may be a new mechanism for LUAD progression.

Integrated analysis of colorectal cancer metastasis identifies characteristics of tumor cell during metastasis.

Background: Metastasis is the main cause of death in colorectal cancer (CRC). Metastasis is a sequential and dynamic process, but the development of tumor cells during this process is unclear. In this study, we aimed to reveal characteristics of tumor cell subset during CRC metastasis. Methods: Single-cell RNA sequence CRC data of normal epithelium, non-metastatic primary tumor, metastatic primary tumor, and liver metastases from gene expression omnibus (GEO) dataset were analyzed to reveal characteristics of CRC metastasis. Primary tumor tissues of three non-metastatic CRC and three metastatic CRC patients from Union Hospital of Tongji Medical College (Wuhan, China) were used to verify the characteristics of CRC metastasis. Results: We identified a metastasis-related cancer cell subset EP1, which was characterized with a high expression of KRT17, LAMC2, EMP1, and PLAC8. EP1 had an enhanced cell-cell interaction, which interacted with SPP+ macrophages and drove them toward anti-inflammatory and immunosuppressive phenotype. Dynamic changes in genes and TF regulons during the metastasis were also revealed. Conclusions: This study advanced our understanding of the development of tumor cells during CRC metastasis and further identified metastasis-related subset and potential therapeutic targets for the treatment and prevention of CRC metastasis.

Single-cell RNA profiling reveals classification and characteristics of mononuclear phagocytes in colorectal cancer.

Colorectal cancer (CRC) is a major cause of cancer mortality and a serious health problem worldwide. Mononuclear phagocytes are the main immune cells in the tumor microenvironment of CRC with remarkable plasticity, and current studies show that macrophages are closely related to tumor progression, invasion and dissemination. To understand the immunological function of mononuclear phagocytes comprehensively and deeply, we use single-cell RNA sequencing and classify mononuclear phagocytes in CRC into 6 different subsets, and characterize the heterogeneity of each subset. We find that tissue inhibitor of metalloproteinases (TIMPs) involved in the differentiation of proinflammatory and anti-inflammatory mononuclear phagocytes. Trajectory of circulating monocytes differentiation into tumor-associated macrophages (TAMs) and the dynamic changes at levels of transcription factor (TF) regulons during differentiation were revealed. We also find that C5 subset, characterized by activation of lipid metabolism, is in the terminal state of differentiation, and that the abundance of C5 subset is negatively correlated with CRC patients' prognosis. Our findings advance the understanding of circulating monocytes' differentiation into macrophages, identify a new subset associated with CRC prognosis, and reveal a set of TF regulons regulating mononuclear phagocytes differentiation, which are expected to be potential therapeutic targets for reversing immunosuppressive tumor microenvironment.

Five glycosylation-related gene signatures predict the prognostic risks of lung adenocarcinoma.

This study aimed to identify glycosylation-related genes associated with lung adenocarcinoma (LUAD) prognosis through comprehensive bioinformatic analysis. Glycosylation-related genes were identified from the Human Gene Nomenclature Committee, and LUAD prognostic genes were screened from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO)-GSE68465 datasets. Glycosylation risk score (GLRS) was calculated to predict LUAD prognostic risk. Samples were grouped into GLRS-high and GLRS-low and compared. The Tumor Immune Dysfunction and Exclusion (TIDE) score was computed to assess the antitumor immune escape possibility after immunotherapy. From 213 glycosylation-related genes, five gene signatures served as prognostic LUAD predictors using univariate and stepwise Cox regression analyses. GLRS-based models were constructed using TCGA and GSE68465 samples; their sensitivity and specificity in predicting LUAD prognosis were confirmed. GLRS was an independent LUAD prognostic factor and contributed to the nomogram to predict patient survival. High GLRS was associated with advanced tumor stage and higher mutation frequencies, estimate scores, and TIDE scores. GLRS-high and GLRS-low patients differed in immune cell infiltration and epithelial-mesenchymal transition (EMT)-related gene expression. Thus, we propose five glycosylation-related gene signatures to predict overall survival and prognostic risks of LUAD. Their regulatory roles may be related to immune invasion, immunotherapy response, mutation, and EMT.

Combined inhibition of PARP and ATR synergistically potentiates the antitumor activity of HER2-targeting antibody-drug conjugate in HER2-positive cancers.

The therapeutic management of various HER2-positive malignancies involves the use of HER2-targeted antibody-drug conjugates (ADCs). The primary mechanism of action of ADCs is the release of cytotoxic chemicals, which leads to single- or double-strand DNA breaks and cell death. Since both endogenous and exogenous sources of DNA damage are unavoidable, cells have evolved DNA damage-repair mechanisms. Therefore, combining inhibitors of DNA damage repair and HER2-targeted ADCs may be a practical strategy for treating HER2-positive cancers. Effects of the HER2-targeted ADC, DS-8201, in combination with PARPi (AZD2281), a DNA damage repair inhibitor that targets poly(ADP-ribose) polymerase, and ATRi (BAY1895344), which inhibits the serine/threonine kinase ATR, were determined by assessing cell-growth inhibition, apoptosis and cell-cycle arrest, as well as using in vivo pharmacodynamic studies. Combined use of AZD2281 and BAY1895344 synergistically potentiated the inhibitory effects of DS-8201 on the growth of HER2-positive cancer cells, inducing DNA damage and apoptosis, but had no effect on HER2-negative MDA-MB-231 breast cancer cells. Our data demonstrate that DS-8201 and DNA damage repair inhibitors together have synergistic anticancer effects in NCI-N87 xenograft models, effects that may reflect upregulation of γ-H2AX protein in tumor tissues. Collectively, our results indicate that the combination of DS-8201, BAY1895344, and AZD2281 exerts significant synergistic antitumor activity, suggesting that DNA damage-repair inhibitors in combination with HER2-targeted ADCs is a potential approach for treating HER2-positive malignancies, offering a promising strategy for future clinical applications.

Identification of Aging and Young Subtypes for Predicting Colorectal Cancer Prognosis and Immunotherapy Responses.

Colorectal cancer (CRC) is critically related to aging and severely threatens human lives. To better explore the effects of aging on CRC progression and therapy outcome, a reliable aging subtypes identification of CRC is urgently desired. Here, 28 aging-related genes associated with the CRC prognosis were selected by univariate Cox analyses. Based on these 28 genes, CRC patients were divided into the aging subtype and young subtype by non-negative matrix factorization clustering. Aging subtype and young subtype of CRC were identified with distinct molecular features and clinical prognosis. The aging subtype was characterized by upregulation of senescence-associated secretory phenotype, higher frequencies of TP53 and immune checkpoint molecules, and high sensitivity to protein kinase and angiogenesis inhibitors. Furthermore, 14 genes were selected by LASSO penalized Cox regression analyses for aging-related risk signature construction. The constructed aging risk signature exhibited good prediction and the nomogram showed robust discrimination power over the traditional CRC staging system. In conclusion, this study successfully established aging subtype and young subtype of CRC, which is helpful to identify patients with aging characteristics to evaluate prognosis and treatment outcomes. Introducing aging-based subtypes into clinical concern and patient prognostication provides new opportunities for personalized CRC treatment.

Trastuzumab in combination with PEGylated interferon-α1b exerts synergistic antitumor activity through enhanced inhibition of HER2 downstream signaling and antibody-dependent cellular cytotoxicity.

The anti-HER2 monoclonal antibody trastuzumab is the mainstay of treatment for HER2-positive breast and gastric cancer, and its combination with multiple chemotherapeutic agents has represented an effective and rational strategy in the clinic. In this study, we report that trastuzumab in combination with PEGylated interferon-α1b (IFN-α1b), a polyethylene glycol (PEG)-conjugated form of a subtype of interferon alpha (IFN-α), synergistically inhibited the proliferation of HER2-positive cells, including BT-474 and SK-BR-3 breast cancer cells and NCI-N87 gastric cancer cells, and also induced their apoptosis, but had no effect on HER2-negative MDA-MB-231 breast cancer cells. Trastuzumab inhibited phosphorylation of HER2, AKT and ERK, an effect that was enhanced by PEGylated IFN-α1b, likely owing to PEGylated IFN-α1b-mediated downregulation of HER2 through the lysosomal degradation pathway. Moreover, PEGylated IFN-α1b significantly enhanced trastuzumab-mediated antibody-dependent cellular cytotoxicity (ADCC) in HER2-positive cells. Importantly, trastuzumab combined with PEGylated IFN-α1b exhibited significant synergistic antitumor activity in HER2-positive BT-474 xenografts, an effect that was associated with enhanced inhibition of HER2 expression and AKT and ERK phosphorylation. Strikingly, depletion of natural killer cells with anti-Asialo GM1 antibody abrogated the synergistic antitumor activity, indicating that augmented ADCC is essential for this synergy. Taken together, our findings indicate that both enhanced inhibition of HER2 downstream signaling and augmented ADCC contribute to the synergistic antitumor activity of trastuzumab with PEGylated IFN-α1b, and imply that combining trastuzumab with PEGylated IFN-α1b could be a promising strategy for HER2-positive cancers.

TSL-1502, a glucuronide prodrug of a poly (ADP-ribose) polymerase (PARP) inhibitor, exhibits potent anti-tumor activity in preclinical models.

Poly (ADP-ribose) polymerase (PARP) enzymes play an important role in the cellular response to DNA damage and the inhibition of PARP causes synthetic lethality in homologous recombination (HR)-deficient cancer. Multiple PARP inhibitors have been developed and have shown remarkable clinical benefits. However, treatment-related toxicities, especially the hematologic toxicities, are common and restrict the clinical applications of PARP inhibitors. In this study, we designed the first glucuronide prodrug of PARP inhibitor, TSL-1502, based on a novel and highly potent PARP inhibitor TSL-1502M. TSL-1502M exhibited promising inhibitory activity on PARP1/2, significantly induced DNA double strand breaks, G2/M arrest and apoptosis in HR-deficient cells, selectively inhibited the proliferation of HR-deficient cancer cells and sensitized both HR-deficient and HR-proficient cancer cells to conventional chemotherapy. Notably, TSL-1502M was superior to olaparib, the first-in-class PARP inhibitor, in all these processes. TSL-1502 had no inhibitory effects on PARP1/2 itself, but could selectively liberate the active drug TSL-1502M in tumor after administration in nude mice. Moreover, TSL-1502 elicited significant more potent inhibitory effects than olaparib in HR-deficient tumors, and sensitized chemotherapy in both HR-deficient and HR-proficient tumors. No severe toxicities were caused by TSL-1502 in this study. Based on the encouraging preclinical antitumor activity and the selective decomposition characteristic of TSL-1502, a clinical phase I study was initiated in China, and an Investigational New Drug (IND) was granted by the US FDA. TSL-1502 could represent a new potential therapeutic choice of PARP inhibitors.

Third-generation EGFR inhibitor HS-10296 in combination with famitinib, a multi-targeted tyrosine kinase inhibitor, exerts synergistic antitumor effects through enhanced inhibition of downstream signaling in EGFR-mutant non-small cell lung cancer cells.

BACKGROUND: As a highly heterogeneous disease, lung cancer has a multitude of cellular components and patterns of gene expression which are not dependent on a single mutation or signaling pathway. Thus, using combined drugs to treat lung cancer may be a practical strategy. METHODS: The combined antitumor effects of HS-10296, a third-generation EGFR inhibitor targeting EGFR T790M mutation, with the multitargeted tyrosine kinase inhibitor (TKI) famitinib in non-small cell lung cancer (NSCLC) were evaluated by in vitro methods such as cell proliferation, apoptosis, angiogenesis assays, and in vivo animal efficacy studies. RESULTS: Famitinib strengthened the effects of HS-10296 on inhibiting proliferation and inducing apoptosis of NSCLC cells, possibly by synergistic inhibition of AKT and ERK phosphorylation. Meanwhile, HS-10296 significantly potentiated the effects of famitinib on inhibiting the proliferation and migration of HUVEC, which may be through synergistic inhibition of ERK phosphorylation in HUVEC, suggesting that HS-10296 may improve the inhibition of angiogenesis by famitinib. Moreover, combination of HS-10296 and famitinib exerted synergistic antitumor activity in NCI-H1975 and PC-9 xenograft models, and this effect may be accomplished by synergistic inhibition of phosphorylation of AKT and ERK and tumor angiogenesis in tumor tissues. CONCLUSIONS: Collectively, our results indicate that HS-10296 and famitinib exhibit significant synergistic antitumor activity, suggesting that the third-generation EGFR inhibitor combined with VEGFR inhibitor provides a promising strategy in the treatment of EGFR-mutant NSCLC.

HAS2-AS1 Acts as a Molecular Sponge for miR-137 and Promotes the Invasion and Migration of Glioma Cells by Targeting EZH2.

This study aims to explore the molecular mechanism by which HAS2-AS1 acts as a ceRNA to promote the invasion and migration of glioma cells, which will provide a novel potential target for the targeted therapy of glioma. Gene expression profiles and corresponding clinical data were accessed from the TCGA_LGG and TCGA_GBM databases and then differential analysis was conducted using the "edgeR" package. miRDB, miRTarBase and TargetScan databases were employed to predict target genes and sequentially a ceRNA network was constructed. Quantitative real-time PCR was performed to detect gene expression in glioma cells. Transwell assay was operated to assess cell migratory and invasive abilities. Western blot was conducted to evaluate the protein expression. Dual-luciferase reporter assay and RNA immunoprecipitation experiment were performed to validate the targeting relationship between genes. HAS2-AS1 was markedly upregulated in glioma, and the overall survival time of patients with high HAS2-AS1 expression was significantly shorter than that of patients with low one. Silencing HAS2-AS1 inhibited the migration and invasion of glioma cells, while overexpressing HAS2-AS1 produced opposite results. miR-137 was validated as a direct target of and negatively regulated by HAS2-AS1. Further exploration of the downstream target gene indicated that EZH2 competed with HAS2-AS1 to interact with miR-137. Suppressing miR-137 or up-regulating EZH2 reversed the impact of HAS2-AS1 knockdown on glioma cell invasion and migration. HAS2-AS1 regulates EZH2 by sponging miR-137 for the migratory and invasive abilities of glioma cells, which provides a new idea for exploring metastasis mechanism of glioma.

YES1 amplification confers trastuzumab-emtansine (T-DM1) resistance in HER2-positive cancer.

BACKGROUND: Trastuzumab-emtansine (T-DM1), one of the most potent HER2-targeted drugs, shows impressive efficacy in patients with HER2-positive breast cancers. However, resistance inevitably occurs and becomes a critical clinical problem. METHODS: We modelled the development of acquired resistance by exposing HER2-positive cells to escalating concentrations of T-DM1. Signalling pathways activation was detected by western blotting, gene expression was analysed by qRT-PCR and gene copy numbers were determined by qPCR. The role of Yes on resistance was confirmed by siRNA-mediated knockdown and stable transfection-mediated overexpression. The in vivo effects were tested in xenograft model. RESULTS: We found that Yes is overexpressed in T-DM1-resistant cells owing to amplification of chromosome region 18p11.32, where the YES1 gene resides. Yes activated multiple proliferation-related signalling pathways, including EGFR, PI3K and MAPK, and led to cross-resistance to all types of HER2-targeted drugs, including antibody-drug conjugate, antibody and small molecule inhibitor. The outcome of this cross-resistance may be a clinically incurable condition. Importantly, we found that inhibiting Yes with dasatinib sensitised resistant cells in vitro and in vivo. CONCLUSIONS: Our study revealed that YES1 amplification conferred resistance to HER2-targeted drugs and suggested the potential application of the strategy of combining HER2 and Yes inhibition in the clinic.

Early differential diagnosis model for acute radiation pneumonitis based on multiple parameters.

OBJECTIVE: The present study aimed to construct a diagnosis model for the early differentiation of acute radiation pneumonitis (ARP) and infectious pneumonitis based on multiple parameters. METHODS: The present study included data of 152 patients admitted to the Department of Radiochemotherapy, Tangshan People's Hospital, who developed ARP (91 patients) or infectious pneumonia (IP; 61 patients) after radiotherapy. The radiophysical parameters, imaging characteristics, serological indicators, and other data were collected as independent variables, and ARP was considered as a dependent variable. Logistics univariate analysis and Spearman correlation analysis were used for selecting independent variables. Logistics multivariate analysis was used to fit the variables into the regression model to predict ARP. RESULTS: The univariate analysis showed that the positional relation between lesions and V20 area (PRLV), procalcitonin (PCT), C-reactive protein (CRP), mean lung dose (MLD), and lung volume receiving ≥20 Gy (V20) correlated with ARP while the planning target volume (PTV) dose marginally correlated with ARP. The multivariate analysis showed that the PRLV, PCT, white blood cell (WBC), and MLD were independent diagnostic factors. The nomogram was drawn on the basis of the logistics regression model. The area under the curve (AUC) of the model was 0.849, which was significantly better than that of a single indicator and the sensitivity and specificity of the model were high (82.4 and 82.0%, respectively). These results predicted by the model were highly consistent with the actual diagnostic results. The decision curve analysis (DCA) demonstrated a satisfactory positive net benefit of the model. CONCLUSION: The diagnosis model constructed in the present study is of certain value for the differential diagnosis of ARP and IP.

The role of procalcitonin in differential diagnosis between acute radiation pneumonitis and bacterial pneumonia in lung cancer patients receiving thoracic radiotherapy.

Acute Radiation Pneumonitis (ARP) is one of the most common dose-limiting toxicities of thoracic radiotherapy. The accurate diagnosis of ARP remains a challenge because of the lack of a rapid biomarker capable of differentiating ARP from bacterial pneumo (BP). The aim of this study was to investigate the potential usefulness of procalcitonin (PCT) in the differential diagnosis of ARP and BP. Lung cancer patients who had undergone thoracic radiotherapy within 6 months and were admitted to hospital for ARP or BP were retrospectively analyzed. The serum levels of PCT, C-reactive protein (CRP) and white blood cells (WBC) were compared between the two groups. Receiver operating characteristic (ROC) curve was used to assess the diagnostic value of PCT, CRP and WBC in the differential diagnosis of ARP and BP and determine the best cut-off values. One hundred eighteen patients were included. Among them, seventy-seven patients were diagnosed with ARP, and 41 patients were diagnosed with BP. The PCT concentrations for patients diagnosed with ARP group were significantly lower than those in the BP group (P < 0.001). There were no differences in CRP and WBC between the two groups. The areas under the ROC curves (AUC) for PCT, CRP and WBC were 0.745, 0.589 and 0.578, respectively. The best cutoff values of PCT, CRP and WBC were 0.47 µg/L, 54.5 mg/L and 9.9 × 109/L, respectively. Low serum PCT levels are associated with ARP. PCT is a useful biomarker to distinguish ARP from BP.

SHR-A1403, a novel c-mesenchymal-epithelial transition factor (c-Met) antibody-drug conjugate, overcomes AZD9291 resistance in non-small cell lung cancer cells overexpressing c-Met.

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) have been used as the first-line treatment of non-small cell lung cancers (NSCLC) harboring EGFR-activating mutations, but acquired resistance is ubiquitous and needs to be solved urgently. Here, we introduce an effective approach for overcoming resistance to the EGFR-TKI, AZD9291, in NSCLC cells using SHR-A1403, a novel c-mesenchymal-epithelial transition factor (c-Met)-targeting antibody-drug conjugate (ADC) consisting of an anti-c-Met monoclonal antibody (c-Met mAb) conjugated to a microtubule inhibitor. Resistant cells were established by exposing HCC827 to increasing concentrations of EGFR-TKI. c-Met was found to be overexpressed in most resistant cells. AZD9291 resistance was partially restored by combination of AZD9291 and crizotinib only in resistant cells overexpressing phospho-c-Met, which synergistically inhibited c-Met-mediated phosphorylation of the downstream targets ERK1/2 and AKT. In resistant cells overexpressing c-Met, neither crizotinib nor c-Met mAb was able to overcome AZD9291 resistance. In contrast, SHR-A1403 strongly inhibited proliferation of AZD9291-resistant HCC827 overexpressing c-Met, regardless of the levels of c-Met phosphorylation. SHR-A1403 bound to resistant cells overexpressing c-Met was internalized into cells and released associated microtubule inhibitor, resulting in cell-killing activity that was dependent on c-Met expression levels only, irrespective of the involvement of c-Met or EGFR signaling in AZD9291 resistance. Consistent with its activity in vitro, SHR-A1403 significantly inhibited the growth of AZD9291-resistant HCC827 tumors and caused tumor regression in vivo. Thus, our findings show that SHR-A1403 efficiently overcomes AZD9291 resistance in cells overexpressing c-Met, and further indicate that c-Met expression level is a biomarker predictive of SHR-A1403 efficacy.

Pharmacological characterization of TQ05310, a potent inhibitor of isocitrate dehydrogenase 2 R140Q and R172K mutants.

Isocitrate dehydrogenase 2 (IDH2), an important mitochondrial metabolic enzyme involved in the tricarboxylic acid cycle, is mutated in a variety of cancers. AG-221, an inhibitor primarily targeting the IDH2-R140Q mutant, has shown remarkable clinical benefits in the treatment of relapsed or refractory acute myeloid leukemia patients. However, AG-221 has weak inhibitory activity toward IDH2-R172K, a mutant form of IDH2 with more severe clinical manifestations. Herein, we report TQ05310 as the first mutant IDH2 inhibitor that potently targets both IDH2-R140Q and IDH2-R172K mutants. TQ05310 inhibited mutant IDH2 enzymatic activity, suppressed (R)-2-hydroxyglutarate (2-HG) production and induced differentiation in cells expressing IDH2-R140Q and IDH2-R172K, but not in cells expressing wild-type IDH1/2 or mutant IDH1. TQ05310 bound to both IDH2-R140Q and IDH2-R172K, with Q316 being the critical residue mediating the binding of TQ05310 with IDH2-R140Q, but not with IDH2-R172K. TQ05310 also had favorable pharmacokinetic characteristics and profoundly inhibited 2-HG production in a tumor xenografts model. The results of the current study establish a solid foundation for further clinical investigation of TQ05310, and provide new insight into the development of novel mutant IDH2 inhibitors.

Preclinical characterization of SHR6390, a novel CDK 4/6 inhibitor, in vitro and in human tumor xenograft models.

Inhibition of the cyclin-dependent kinase (CDK) 4/6-retinoblastoma (RB) pathway is an effective therapeutic strategy against cancer. Here, we performed a preclinical investigation of the antitumor activity of SHR6390, a novel CDK4/6 inhibitor. SHR6390 exhibited potent antiproliferative activity against a wide range of human RB-positive tumor cells in vitro, and exclusively induced G1 arrest as well as cellular senescence, with a concomitant reduction in the levels of Ser780-phosphorylated RB protein. Compared with the well-known CDK4/6 inhibitor palbociclib, orally administered SHR6390 led to equivalent or improved tumor efficacy against a panel of carcinoma xenografts, and produced marked tumor regression in some models, in association with sustained target inhibition in tumor tissues. Furthermore, SHR6390 overcame resistance to endocrine therapy and HER2-targeting antibody in ER-positive and HER2-positive breast cancer, respectively. Moreover, SHR6390 combined with endocrine therapy exerted remarkable synergistic antitumor activity in ER-positive breast cancer. Taken together, our findings indicate that SHR6390 is a novel CDK4/6 inhibitor with favorable pharmaceutical properties for use as an anticancer agent.

Pharmacologic characterization of fluzoparib, a novel poly(ADP-ribose) polymerase inhibitor undergoing clinical trials.

Poly(ADP-ribose) polymerase (PARP) enzymes play an important role in repairing DNA damage and maintaining genomic stability. Olaparib, the first-in-class PARP inhibitor, has shown remarkable clinical benefits in the treatment of BRCA-mutated ovarian or breast cancer. However, the undesirable hematological toxicity and pharmacokinetic properties of olaparib limit its clinical application. Here, we report the first preclinical characterization of fluzoparib (code name: SHR-3162), a novel, potent, and orally available inhibitor of PARP. Fluzoparib potently inhibited PARP1 enzyme activity and induced DNA double-strand breaks, G2 /M arrest, and apoptosis in homologous recombination repair (HR)-deficient cells. Fluzoparib preferentially inhibited the proliferation of HR-deficient cells and sensitized both HR-deficient and HR-proficient cells to cytotoxic drugs. Notably, fluzoparib showed good pharmacokinetic properties, favorable toxicity profile, and superior antitumor activity in HR-deficient xenografts models. Furthermore, fluzoparib in combination with apatinib or with apatinib plus paclitaxel elicited significantly improved antitumor responses without extra toxicity. Based on these findings, studies to evaluate the efficacy and safety of fluzoparib (phase II) and those two combinations (phase I) have been initiated. Taken together, our results implicate fluzoparib as a novel attractive PARP inhibitor.

Pharmacologic characterization of CT-711, a novel dual inhibitor of ALK and c-Met.

Anaplastic lymphoma kinase (ALK) is a validated molecular target for patients harboring ALK rearrangement, which triggers the development of ALK inhibitors. However, the activation of mesenchymal-epithelial transition factor (c-Met) has emerged as a common cause of acquired resistance induced by selective ALK inhibitors. Herein, we report the first preclinical characterization of CT-711, a novel dual inhibitor of ALK and c-Met. CT-711 demonstrates potent inhibitory activity against ALK kinase activity. Moreover, CT-711 profoundly inhibits ALK signal transduction and thereby induces G1 phase arrest and apoptosis, and results in remarkable anti-proliferative activity against ALK-driven cancer cells. Furthermore, CT-711 effectively inhibits c-Met kinase activity and potently overcomes the resistance mediated by c-Met activation. When orally administered to nude mice bearing xenografts, CT-711 exhibits favorable pharmacokinetic properties and robust antitumor activity. It is noteworthy that CT-711 is superior to crizotinib, the first-in-class ALK inhibitor, in the treatment of ALK-driven cancers in various models. The results of the current study provide a solid foundation for the clinical investigation of CT-711 in patients with tumors harboring ALK rearrangement.

Pharmacological characterization of hetrombopag, a novel orally active human thrombopoietin receptor agonist.

Nonpeptide thrombopoietin receptor (TPOR/MPL) agonists, such as eltrombopag, have been used to treat thrombocytopenia of various aetiologies. Here, we investigated the pharmacological properties of hetrombopag, a new orally active small-molecule TPOR agonist, in preclinical models. Hetrombopag specifically stimulated proliferation and/or differentiation of human TPOR-expressing cells, including 32D-MPL and human hematopoietic stem cells, with low nanomolar EC50 values through stimulation of STAT, PI3K and ERK signalling pathways. Notably, hetrombopag effectively up-regulated G1 -phase-related proteins, including p-RB, Cyclin D1 and CDK4/6, normalized progression of the cell cycle, and prevented apoptosis by modulating BCL-XL/BAK expression in 32D-MPL cells. Moreover, hetrombopag and TPO acted additively in stimulating TPOR-dependent signalling, promoting cell viability, and preventing apoptosis. Orally administered hetrombopag specifically promoted the viability and growth of 32D-MPL cells in hollow fibres implanted into nude mice with much higher potency than that of the well-known TPOR agonist, eltrombopag, in association with activation of TPOR-dependent signal transduction in vivo. Taken together, our findings indicate that, given its favourable pharmacological characteristics, hetrombopag may represent a new, orally active, small-molecule TPOR agonist for patients with thrombocytopenia.

DCZ3112, a novel Hsp90 inhibitor, exerts potent antitumor activity against HER2-positive breast cancer through disruption of Hsp90-Cdc37 interaction.

Hsp90 regulates the stability of oncoproteins important in tumor development and progression, and represents a potential therapeutic target. However, all Hsp90 inhibitors currently in clinical trials target Hsp90 ATPase activity and exhibit low selectivity and high toxicity. In this study, we discovered a new Hsp90 inhibitor, DCZ3112, with a novel mechanism of action. DCZ3112 directly bound to the N-terminal domain of Hsp90 and inhibited Hsp90-Cdc37 interaction without inhibiting ATPase activity. DCZ3112 inhibited the proliferation predominantly in HER2-positive breast cancer cells, including those resistant to the classical Hsp90 inhibitor geldanamycin, which mainly targets ATPase. DCZ3112 produced synergistic in vitro activity in inhibiting cell proliferation, inducing G1-phase arrest and apoptosis, and reducing AKT and ERK phosphorylation. Consistent with this, DCZ3112 alone inhibited the growth of HER2-positive BT-474 xenografts, and exhibited enhanced antitumor activity when combined with the anti-HER2 antibody trastuzumab. Importantly, DCZ3112 also significantly inhibited the growth of trastuzumab-resistant BT-474 cells, and combined treatment retained synergistic antitumor activity. Thus, our findings show that disrupting Hsp90-Cdc37 interaction may represent a promising strategy against HER2-positive breast cancer, especially those with acquired resistance to trastuzumab.