The orphan nuclear receptor 4A1 (NR4A1) is overexpressed in mammary tumors and breast cancer cell lines. The functional activity of this receptor was investigated by RNA interference with oligonucleotides targeted to NR4A1 (siNR4A1) and by treatment with NR4A1 antagonists. Breast cancer cells were treated with NR4A1 antagonists or transfected with siNR4A. Effects on cell proliferation and apoptosis as well as specific genes associated with these responses were investigated in MCF-7, SKBR3, and MDA-MB-231 cells, and in athymic nude mice bearing MDA-MB-231 cells as xenografts. Transfection of MCF-7, MDA-MB-231, and SKBR3 breast cancer cells with siNR4A1 decreased cell proliferation and induced apoptosis in these cell lines. Transfection of breast cancer cells with siNR4A1 also decreased expression of Sp-regulated genes including survivin, bcl-2, and epidermal growth factor receptor, inhibited mTOR signaling in MCF-7 cells that express WT p53, and activated oxidative and endoplasmic reticulum stress through downregulation of thioredoxin domain-containing 5 and isocitrate dehydrogenase 1. 1,1-Bis(3 0 -indolyl)-1-(p-substituted phenyl)methanes (C-DIMs) are NR4A1 ligands that act as NR4A1 antagonists. Treatment with selected analogs also inhibited breast cancer cell and tumor growth and induced apoptosis.The effects of C-DIM/NR4A1 antagonists were comparable to those observed after NR4A1 knockdown. Results with siNR4A1 or C-DIMs/NR4A1 antagonists in breast cancer cells and tumors were similar to those previously reported in pancreatic, lung, and colon cancer cells. They demonstrate the potential clinical applications of NR4A1 antagonists in patients with tumors that overexpress this receptor.

cOverexpression of the nuclear receptor 4A1 (NR4A1) in breast cancer patients is a prognostic factor for decreased survival and increased metastasis, and this has been linked to NR4A1-dependent regulation of transforming growth factor ␤ (TGF-␤) signaling. Results of RNA interference studies demonstrate that basal migration of aggressive SKBR3 and MDA-MB-231 breast cancer cells is TGF-␤ independent and dependent on regulation of ␤1-integrin gene expression by NR4A1 which can be inhibited by the NR4A1 antagonists 1,1-bis(3=-indolyl)-1-(p-hydroxyphenyl)methane (DIM-C-pPhOH) and a related p-carboxymethylphenyl [1,1-bis(3=-indolyl)-1-(p-carboxymethylphenyl)methane (DIM-C-pPhCO 2 Me)] analog. The NR4A1 antagonists also inhibited TGF-␤-induced migration of MDA-MB-231 cells by blocking nuclear export of NR4A1, which is an essential step in TGF-␤-induced cell migration. We also observed that NR4A1 regulates expression of both ␤1-and ␤3-integrins, and unlike other ␤1-integrin inhibitors which induce prometastatic ␤3-integrin, NR4A1 antagonists inhibit expression of both ␤1-and ␤3-integrin, demonstrating a novel mechanism-based approach for targeting integrins and integrin-dependent breast cancer metastasis. Cell adhesion and attachment are essential for tissue integrity and cellular homeostasis, and the heterodimeric integrin cell surface receptors play a critical role in these processes (1-3). There are 18 different ␣ subunits and 8 different ␤ subunits that form 24 ␣␤-integrin receptor heterodimers, and the large 12-member ␤1-integrin subgroup bind multiple extracellular matrix (ECM) molecules to activate multiple intracellular pathways and also induce cross talk with other signaling systems (1-3). The functions of integrin heterodimers are highly tissue specific, and many human pathologies also involve integrin signaling (reviewed in references 4 and 5). ␤1-Integrin is highly expressed in most tumors and is associated with a negative prognostic significance such as overall and disease-free survival, recurrence, and metastasis for head and neck and squamous cell carcinoma, melanoma, lung, breast, prostate, laryngeal, and pancreatic cancers (6-17). A recent immunostaining study of 225 breast invasive ductal carcinomas (IDCs) showed that ␤1-integrin was overexpressed in 32.8% of patients with IDCs (13). Numerous studies show that focal adhesion kinase (FAK) which is downstream from ␤1-integrin is also a negative prognostic factor for breast cancer patients (18)(19)(20). The important functional role of ␤1-integrin has been demonstrated in mouse models expressing erbB2 under the control of the mouse mammary tumor virus and crossed with mammary tissue-specific ␤1-integrin-deficient mice. These mice exhibit a decrease in tumor volume, increased apoptosis, and decreased lung metastasis compared to animals expressing wild-type ␤1-integrin (21-23). Although small molecules, peptides, and antibodies that inhibit ␤1-integrin signaling have been developed, clinical agents that target ␤1-integrin for cancer chemotherapy are not cur...

The purpose of the present study was to evaluate the effect of Telmisartan (Tel) and Losartan (Los) on nanoparticle intratumoral distribution and anticancer effects in lung cancer. A549 lung tumor cells were orthotopically and metastatically administered to Nu/nu mice. Fluorescent polystyrene nanoparticles (FPNPs, size ~200 nm) beads were used to study their intratumoral distribution after Tel and Los treatments. Animals were administered with FPNPs and after 2h, FPNPs intratumoral distribution was studied by fluorescent microscopy. Tel (~1.12 mg/kg) and Los (~4.5 mg/kg) was administered by inhalation delivery at alternative days for 4 weeks to tumor bearing animals. Collagen-1, transforming growth factor beta 1 (TGF-β1), cleaved caspase-3, Vimentin and E-Cadherin expressions were studied by western blotting. To correlate the AT1 receptor blockage to anticancer effects, VEGF levels and microvessel densities (MVD) were quantified. Los and Tel treated group resulted in the 5.33 and 14.33 fold increase respectively in the FPNPs intratumoral distribution as compared to the controls. Tel treatment attenuated 2.23 and 1.70 fold Collagen 1 expression compared to untreated control and Los groups, respectively. Further, in Tel and Los treated groups, the TGF-β1 active levels were significantly (p<0.05) decreased. Tel (at four times less dose) was 1.89 and 1.92 fold superior in anticancer activity to Los respectively in A549 orthotopic and metastatic tumor models (p<0.05) when given by inhalation route. Tel, by virtue of its dual pharmacophoric nature could be an ideal candidate for combination therapy to improve the nanoparticle intratumoral distribution and anticancer effects.

BackgroundThe poor bioavailability of Berberine (BBR) and Betulinic acid (BA) limits the development of these promising anticancer agents for clinical use. In the current study, BBR and BA in spray dried (SD) mucoadhesive microparticle formulations were prepared.MethodsA patented dual channel spray gun technology established in our laboratory was used for both formulations. Gastrointestinal (GI) permeability studies were carried out using Caco-2 cell monolayer grown in in-vitro system. The oral bioavailability and pharmacokinetic profile of SD formulations were studied in Sprague Dawley rats. A549 orthotopic and H1650 metastatic NSCLC models were utilized for the anticancer evaluations.ResultsPharmacokinetic studies demonstrated that BBR and BA SD formulations resulted in 3.46 and 3.90 fold respectively, significant increase in plasma Cmax concentrations. AUC levels were increased by 6.98 and 7.41 fold in BBR and BA SD formulations, respectively. Compared to untreated controls groups, 49.8 & 53.4% decrease in the tumor volumes was observed in SD formulation groups of BBR and BA, respectively. Molecular studies done on excised tumor (A549) tissue suggested that BBR in SD form resulted in a significant decrease in the survivin, Bcl-2, cyclin D1, MMP-9, HIF-1α, VEGF and CD31 expressions. Cleaved caspase 3, p53 and TUNEL expressions were increased in SD formulations. The RT-PCR analysis on H1650 tumor tissue suggested that p38, Phospho-JNK, Bax, BAD, cleaved caspase 3&8 mRNA expressions were significantly increased in BA SD formulations. Chronic administration of BBR and BA SD formulations did not show any toxicity.ConclusionsDue to significant increase in oral bioavailability and superior anticancer effects, our results suggest that spray drying is a superior alternative formulation approach for oral delivery of BBR and BA.

The orphan nuclear receptor NR4A1 is expressed in tumors from rhabdomyosarcoma (RMS) patients and Rh30 and RD RMS cell lines, and we used RNA interference (RNAi) to investigate the role of this receptor in RMS cells. Knockdown of NR4A1 in Rh30 cells decreased cell proliferation, induced Annexin V staining and induced polyADPribose polymerase (PARP) cleavage and these results were similar to those observed in other solid tumors. Previous studies show that NR4A1 regulates expression of growth promoting/pro-survival genes with GC-rich promoters, activates mTOR through suppression of p53, and maintains low oxidative stress by regulating expression of isocitrate dehydrogenase 1 (IDH1) and thioredoxin domain containing 5 (TXNDC5). Results of RNAi studies demonstrated that NR4A1 also regulates these pathways and associated genes in RMS cells and thereby exhibits pro-oncogenic activity. 1,1-Bis(3-indolyl)-1-(p-substituted phenyl)methane (C-DIM) analogs containing p-hydroxyl (DIM-C-pPhOH) and p-carboxymethyl (DIM-C-pPhCO2Me) substituents are NR4A1 ligands that decreased NR4A1-dependent transactivation in RMS cells and inhibited RMS cell and tumor growth and induced apoptosis. Moreover, the effects of NR4A1 knockdown and the C-DIM/NR4A1 antagonists were comparable as inhibitors of NR4A1-dependent genes/pathways. Both NR4A1 knockdown and treatment with DIM-C-pPhOH and DIM-C-pPhCO2Me also induced ROS which activated stress genes and induced sestrin 2 which activated AMPK and inhibited mTOR in the mutant p53 RMS cells. Since NR4A1 regulates several growth-promoting/pro-survival pathways in RMS, the C-DIM/NR4A1 antagonists represent a novel mechanism-based approach for treating this disease alone or in combination and thereby reducing the adverse effects of current cytotoxic therapies.