Fusion of apoptosis-related protein Cytochrome c with anti-HER-2 single-chain antibody targets the suppression of HER-2+ breast cancer.

Cancer treatment has gradually developed from toxic chemotherapy to targeted therapy with fewer side effects. Approximately 30% of breast cancer patients overexpress human epidermal growth factor receptor 2 (HER-2). Previous studies have successfully produced single-chain antibodies (scFv) targeting HER-2+ breast cancer; however, scFv have poor stability, easy aggregation and a shorter half-life, which have no significant effect on targeting therapy. Moreover, scFv has been considered as a drug delivery platform that can kill target cells by effector molecules. However, the functional killing domains of immunotoxins are mainly derived from plant or bacterial toxins, which have a large molecular weight, low tissue permeability and severe side effects. To address these concerns, we designed several apoptotic immune molecules to replace exogenous toxins using endogenous apoptosis-related protein DNA fragmentation factor 40 (DFF40) and tandem-repeat Cytochrome c base on caspase-3 responsive peptide (DEVD). Our results suggest that DFF40 or Cytc fusion scFv specifically targets HER-2 overexpressing breast cancer cells (SK-BR-3 and BT-474) rather than HER-2 negative cells (MDA-MB-231 and MCF-7). Following cellular internalization, apoptosis-related proteins inhibited tumour activity by initiating endogenous apoptosis pathways, which significantly reduced immunogenicity and toxic side effects. Therefore, we suggest that immunoapoptotic molecules may become potential drugs for targeted immunotherapy of breast cancer.

Preferential Inhibition of Wnt/ß-Catenin Signaling by Novel Benzimidazole Compounds in Triple-Negative Breast Cancer.

Wnt/ß-catenin signaling is upregulated in triple-negative breast cancer (TNBC) compared to other breast cancer subtypes and normal tissues. Current Wnt/ß-catenin inhibitors, such as niclosamide, target the pathway nonspecifically and exhibit poor pharmacokinetics/pharmacodynamics in vivo. Niclosamide targets other pathways, including mTOR, STAT3 and Notch. Novel benzimidazoles have been developed to inhibit Wnt/ß-catenin signaling with greater specificity. The compounds SRI33576 and SRI35889 were discovered to produce more cytotoxicity in TNBC cell lines than in noncancerous cells. The agents also downregulated Wnt/ß-catenin signaling mediators LRP6, cyclin D1, survivin and nuclear active ß-catenin. In addition, SRI33576 did not affect mTOR, STAT3 and Notch signaling in TNBC and noncancerous cells. SRI35889 inhibited mTOR signaling less in noncancerous than in cancerous cells, while not affecting STAT3 and Notch pathways. Compounds SRI32529, SRI35357 and SRI35361 were not selectively cytotoxic against TNBC cell lines compared to MCF10A cells. While SRI32529 inhibited Wnt/ß-catenin signaling, the compound also mitigated mTOR, STAT3 and Notch signaling. SRI33576 and SRI35889 were identified as cytotoxic and selective inhibitors of Wnt/ß-catenin signaling with therapeutic potential to treat TNBC in vivo.

Targeting the Wnt/ß-catenin pathway in primary ovarian cancer with the porcupine inhibitor WNT974.

Preclinical studies in ovarian cancer have demonstrated upregulation of the Wnt/ß-catenin pathway promoting tumor proliferation and chemoresistance. Our objective was to evaluate the effect of the Wnt/ß-catenin pathway inhibitor, WNT974, in primary ovarian cancer ascites cells. Ascites cells from patients with papillary serous ovarian cancer were isolated and treated with 1 µM WNT974±100 µM carboplatin. Viability was evaluated with the ATPlite assay. The IC50 was calculated using a dose-response analysis. Immunohistochemistry (IHC) was performed on ascites cells and tumor. Expression of R-spondin 2 (RSPO2), RSPO3, PORCN, WLS, AXIN2, and three previously characterized RSPO fusion transcripts were assessed using Taqman assays. Sixty ascites samples were analyzed for response to WNT974. The ascites samples that showed a decrease in ATP concentration after treatment demonstrated no difference from the untreated cells in percent viability with trypan blue staining. Flow cytometry demonstrated fewer cells in the G2 phase and more in the G1 and S phases after treatment with WNT974. Combination therapy with WNT974 and carboplatin resulted in a higher percentage of samples that showed ≥30% reduction in ATP concentration than either single drug treatment. IHC analysis of Wnt pathway proteins suggests cell cycle arrest rather than cytotoxicity after WNT974 treatment. QPCR indicated that RSPO fusions are not prevalent in ovarian cancer tissues or ascites. However, higher PORCN expression correlated to sensitivity to WNT974 (P=0.0073). In conclusion, WNT974 produces cytostatic effects in patient ascites cells with primary ovarian cancer through inhibition of the Wnt/ß-catenin pathway. The combination of WNT974 and carboplatin induces cytotoxicity plus cell cycle arrest in a higher percentage of ascites samples than with single drug treatment. RSPO fusions do not contribute to WNT974 sensitivity; however, higher PORCN expression indicates increased WNT974 sensitivity.

Niclosamide Analogs for Treatment of Ovarian Cancer.

OBJECTIVE: Niclosamide has shown activity against ovarian cancer in vitro; however, it has low bioavailability in vivo. Therefore, we investigated the cytotoxicity of niclosamide analogs in combination with carboplatin against ovarian cancer patient ascites cells and tissue slices. MATERIALS/METHODS: Tumorspheres were isolated from ascites collected from patients undergoing ovarian cancer surgery and plated at 10,000 cells per 50 µL into low attachment plates. Tumor slices were also processed at the time of surgery. These were treated concurrently with niclosamide or analogs (0.1-5 µM) and carboplatin (5-150 µM). At 48 hours, cell viability was assessed with ATPlite assay. Western blotting was used to determine expression of Wnt/ß-catenin proteins in ascites cells. RESULTS: Cytotoxicity of niclosamide and its analogs in combination with carboplatin was demonstrated in 24 patient ascites samples. Increased cytotoxicity was seen with 2 analogs in 23 patient ascites samples when compared with niclosamide. Similar cytotoxicity was produced in an ex vivo tumor slice model. Western blot analysis showed decreased expression of Wnt/ß-catenin proteins with niclosamide and analog treatment in a dose-dependent fashion. CONCLUSIONS: The niclosamide-like analogs produced cytotoxicity both alone and in combination with carboplatin against tumorspheres from patient ascites and slices from solid tumor samples. Tumor slices showed similar cytotoxicity to matched ascites samples. Western blots showed down-regulation of Wnt pathway-associated proteins in patient samples treated with niclosamide analogs. These results suggest that more soluble niclosamide analogs may be useful for the treatment of ovarian cancer in combination with chemotherapy.

Inhibition of the Wnt/ß-catenin pathway enhances antitumor immunity in ovarian cancer.

BACKGROUND: The Wnt/ß-catenin pathway is linked to tumorigenesis in a variety of tumors and promotes T cell exclusion and resistance to checkpoint inhibitors. We sought to determine whether a small molecule inhibitor of this pathway, WNT974, would impair tumor growth, affect gene expression patterns, and improve the immune response in human and murine ovarian cancer models. METHODS: Human ovarian cancer cells were treated with WNT974 in vitro. RNAseq libraries were constructed and differences in gene expression patterns between responders and nonresponders were compared to The Cancer Genome Atlas (TCGA). Mice with subcutaneous or intraperitoneal ID8 ovarian cancer tumors were treated with WNT974, paclitaxel, combination, or control. Tumor growth and survival were measured. Flow cytometry and ß-TCR repertoire analysis were used to determine the immune response. RESULTS: Gene expression profiling revealed distinct signatures in responders and nonresponders, which strongly correlated with T cell infiltration patterns in the TCGA analysis of ovarian cancer. WNT974 inhibited tumor growth, prevented ascites formation, and prolonged survival in mouse models. WNT974 increased the ratio of CD8+ T cells to T regulatory cells (Tregs) in tumors and enhanced the effector functions of infiltrating CD4+ and CD8+ T cells. Treatment also decreased the expression of inhibitory receptors on CD8+ T cells. Combining WNT974 with paclitaxel further reduced tumor growth, prolonged survival, and expanded the T cell repertoire. CONCLUSIONS: These findings suggest that inhibiting the Wnt/ß-catenin pathway may have a potent immunomodulatory effect in the treatment of ovarian cancer, particularly when combined with paclitaxel.

212Pb-labeled B7-H3-targeting antibody for pancreatic cancer therapy in mouse models.

INTRODUCTION: We recently validated monoclonal antibody (mAb) 376.96 as an effective carrier for targeted α-particle radioimmunotherapy (RIT) with 212Pb in ovarian cancer mouse models. In this study, we tested the binding of radiolabeled mAb 376.96 to human pancreatic ductal adenocarcinoma (PDAC) cells and localization in xenografts in immune-deficient mice and evaluated 212Pb-labeled 376.96 (212Pb-376.96) for PDAC therapy. METHODS: In vitro Scatchard assays assessed the specific binding of 212Pb-376.96 to human PDAC3 adherent differentiated cells and non-adherent cancer initiating cells (CICs) dissociated from tumorspheres. In vitro clonogenic assays were used to measure the proliferation of adherent PDAC3 cells and CIC-enriched tumorspheres treated with 212Pb-376.96 or the irrelevant isotype-matched 212Pb-F3-C25. Mice bearing patient derived pancreatic cancer Panc039 xenografts were i.v. injected with 0.17-0.70 MBq 212Pb-376.96 or isotype control 212Pb-F3-C25, and used for biodistribution and tumor growth inhibition studies. Mice bearing orthotopic PDAC3 xenografts were i.v. co-injected with 99mTc-376.96 and 125I-F3-C25 and used for biodistribution studies. RESULTS: 212Pb-376.96 specifically bound to PDAC3 adherent and dissociated tumorsphere CICs; Kd values averaged 9.0 and 21.7 nM, respectively, with 104-105 binding sites/cell. 212Pb-376.96 inhibited the clonogenic survival of PDAC3 cells or CICs dissociated from tumorspheres 3-6 times more effectively than isotype-matched control 212Pb-F3-C25. Panc039 s.c. tumors showed significantly higher uptake of 212Pb-376.96 (14.0 ±â€¯2.1% ID/g) compared to 212Pb-F3-C25 (6.5 ±â€¯0.9% ID/g, p < .001) at 24 h after dosing. Orthotopic PDAC3 tumors showed significantly higher uptake of 99mTc-376.96 (6.4 ±â€¯1.8% ID/g) compared to 125I-F3-C25 (3.9 ±â€¯0.9% ID/g, p < .05) at 24 h after dosing. Panc039 tumor growth was significantly inhibited by 212Pb-376.96 compared to 212Pb-F3-C25 or non-treated control tumors (p < .05). CONCLUSION: Our results provide evidence for the efficacy of B7-H3 targeted RIT against preclinical models of pancreatic ductal adenocarcinoma (PDAC) and support future studies with 212Pb-376.96 in combination with chemotherapy to potentiate efficacy against PDAC.

Correction: Niclosamide and its analogs are potent inhibitors of Wnt/ß-catenin, mTOR and STAT3 signaling in ovarian cancer.

[This corrects the article DOI: 10.18632/oncotarget.13466.].

Niclosamide and its analogs are potent inhibitors of Wnt/ß-catenin, mTOR and STAT3 signaling in ovarian cancer.

Epithelial ovarian cancer (EOC) is the leading cause of gynecologic cancer mortality worldwide. Platinum-based therapy is the standard first line treatment and while most patients initially respond, resistance to chemotherapy usually arises. Major signaling pathways frequently upregulated in chemoresistant cells and important in the maintenance of cancer stem cells (CSCs) include Wnt/ß-catenin, mTOR, and STAT3. The major objective of our study was to investigate the treatment of ovarian cancer with targeted agents that inhibit these three pathways. Here we demonstrate that niclosamide, a salicylamide derivative, and two synthetically manufactured niclosamide analogs (analog 11 and 32) caused significant inhibition of proliferation of two chemoresistant ovarian cancer cell lines (A2780cp20 and SKOV3Trip2), tumorspheres isolated from the ascites of EOC patients, and cells from a chemoresistant patient-derived xenograft (PDX). This work shows that all three agents significantly decreased the expression of proteins in the Wnt/ß-catenin, mTOR and STAT3 pathways and preferentially targeted cells that expressed the ovarian CSC surface protein CD133. It also illustrates the potential of drug repurposing for chemoresistant EOC and can serve as a basis for pathway-oriented in vivo studies.