Chemoprevention of skin cancer with 1,1-Bis (3'-indolyl)-1-(aromatic) methane analog through induction of the orphan nuclear receptor, NR4A2 (Nurr1)

Comparative safety, pharmacokinetics, and off-target assessment of 1,1-bis(3'-indolyl)-1-(p-chlorophenyl) methane in mouse and dog: implications for therapeutic development

The modified phytochemical derivative, 1,1-bis(3'-indolyl)-1-(p-chlorophenyl) methane (C-DIM12), has been identified as a potential therapeutic platform based on its capacity to improve disease outcomes in models of neurodegeneration and cancer. However, comprehensive safety studies investigating pathology and off-target binding have not been conducted. To address this, we administered C-DIM12 orogastrically to outbred male CD-1 mice for 7 days (50 mg/kg/day, 200 mg/kg/day, and 300 mg/kg/day) and investigated changes in hematology, clinical chemistry, and whole-body tissue pathology. We also delivered a single dose of C-DIM12 (1 mg/kg, 5 mg/kg, 25 mg/kg, 100 mg/kg, 300 mg/kg, 1,000 mg/kg) orogastrically to male and female beagle dogs and investigated hematology and clinical chemistry, as well as plasma pharmacokinetics over 48-h. Consecutive in-vitro off-target binding through inhibition was performed with 10 μM C-DIM12 against 68 targets in tandem with predictive off-target structural binding capacity. These data show that the highest dose C-DIM12 administered in each species caused modest liver pathology in mouse and dog, whereas lower doses were unremarkable. Off-target screening and predictive modeling of C-DIM12 show inhibition of serine/threonine kinases, calcium signaling, G-protein coupled receptors, extracellular matrix degradation, and vascular and transcriptional regulation pathways. Collectively, these data demonstrate that low doses of C-DIM12 do not induce pathology and are capable of modulating targets relevant to neurodegeneration and cancer.

(-)-Epigallocatechin-3-gallate promotes intestinal epithelial proliferation and barrier function after ischemia/reperfusion injury via activation of Nurr1

CONTEXT

(-)-Epigallocatechin-3-gallate (EGCG) is involved in cell proliferation and ischemia/reperfusion (I/R) injury of several organs.

OBJECTIVE

To identify the role of EGCG in intestinal epithelial proliferation and barrier exposed to I/R injury.

MATERIAL AND METHODS

Fifty Sprague-Dawley rats were divided into sham, I/R, I/R + EGCG (12.5 mg/kg), I/R + EGCG (25 mg/kg) and I/R + EGCG (50 mg/kg). I/R group rats were subjected to intestinal ischemia for 1 h and 6 h reperfusion. The rats were supplemented with EGCG 12.5, 25 and 50 mg/kg daily for 3 days via intraperitoneal injection before surgery. We used IEC-6 to expose to hypoxia/reoxygenation (H/R) injury to mimic I/R in vivo. IEC-6 cells were divided into control, H/R and H/R + EGCG (40 μmol/L). The effects of EGCG and its mechanism was explored.

RESULTS

Pharmacological treatment with EGCG notably improves intestinal epithelial proliferation (12.5 mg/kg, 1.74-fold; 25 mg/kg, 2.93-fold, and 50 mg/kg, 4.33-fold) and barrier function after I/R injury. EGCG promoted cell proliferation (2.99-fold) and increased the expression of occludin (2.36-fold) and ZO-1 (1.64-fold) in IEC-6 cells after H/R injury. EGCG promoted proliferation of IEC-6 cells with ED50 values of 18.16 μmol/L. Further investigations indicated that EGCG activated Nurr1 expression in intestine after I/R injury. EGCG promote cell proliferation and increased the expression of occludin and ZO-1 in IEC-6 cells after H/R injury were abrogated in the knockdown of Nurr1 by siRNA.

DISCUSSION AND CONCLUSION

Our findings indicate that EGCG promotes intestinal epithelial cell proliferation and barrier function after I/R injury in vitro and in vivo via activation of Nurr1.

Natural compounds targeting nuclear receptors for effective cancer therapy

Human nuclear receptors (NRs) are a family of forty-eight transcription factors that modulate gene expression both spatially and temporally. Numerous biochemical, physiological, and pathological processes including cell survival, proliferation, differentiation, metabolism, immune modulation, development, reproduction, and aging are extensively orchestrated by different NRs. The involvement of dysregulated NRs and NR-mediated signaling pathways in driving cancer cell hallmarks has been thoroughly investigated. Targeting NRs has been one of the major focuses of drug development strategies for cancer interventions. Interestingly, rapid progress in molecular biology and drug screening reveals that the naturally occurring compounds are promising modern oncology drugs which are free of potentially inevitable repercussions that are associated with synthetic compounds. Therefore, the purpose of this review is to draw our attention to the potential therapeutic effects of various classes of natural compounds that target NRs such as phytochemicals, dietary components, venom constituents, royal jelly-derived compounds, and microbial derivatives in the establishment of novel and safe medications for cancer treatment. This review also emphasizes molecular mechanisms and signaling pathways that are leveraged to promote the anti-cancer effects of these natural compounds. We have also critically reviewed and assessed the advantages and limitations of current preclinical and clinical studies on this subject for cancer prophylaxis. This might subsequently pave the way for new paradigms in the discovery of drugs that target specific cancer types.

Molecular Insights into NR4A2(Nurr1): an Emerging Target for Neuroprotective Therapy Against Neuroinflammation and Neuronal Cell Death

NR4A2 is a nuclear receptor and a transcription factor, with distinctive physiological features. In the cell nuclei of the central nervous system, it is widely expressed and identified as a crucial regulator of dopaminergic (DA) neuronal differentiation, survival, and maintenance. Importantly, it has regulated different genes crucial for dopaminergic signals, and its expression has been diminished in both aged and PD post-mortem brains and reduced in PD patients. In microglia and astrocytes, the expression of NR4A2 has been found where it can be capable of inhibiting the expression of proinflammatory mediators; hence, it protected inflammation-mediated DA neuronal death. In addition, NR4A2 plays neuroprotective role via regulating different signals. However, NR4A2 has been mainly focused on Parkinson's research, but, in recent times, it has been studied in Alzheimer's disease (AD), multiple sclerosis (MS), and stroke. Altered expression of NR4A2 is connected to AD progression, and activation of its may improve cognitive function. It is downregulated in peripheral blood mononuclear cells of MS patients; nonetheless, its role in MS has not been fully clear. miR-145-5p known as a putative regulator of NR4A2 and in a middle cerebral artery occlusion/reperfusion model, anti-miR-145-5p administration promoted neurological outcomes in rat. To date, various activators and modulators of NR4A2 have been discovered and investigated as probable therapeutic drugs in neuroinflammatory and neuronal cell death models. The NR4A2 gene and cell-based therapy are described as promising drug candidates for neurodegenerative diseases. Moreover, microRNA might have a crucial role in neurodegeneration via affecting NR4A2 expression. Herein, we present the role of NR4A2 in neuroinflammation and neuronal cell death focusing on neurodegenerative conditions and display NR4A2 as a promising therapeutic target for the therapy of neuroprotection.

Drug delivery strategies for chemoprevention of UVB-induced skin cancer: A review

Annually, more skin cancer cases are diagnosed than the collective incidence of the colon, lung, breast, and prostate cancer. Persistent contact with sunlight is a primary cause for all the skin malignancies. UVB radiation induces reactive oxygen species (ROS) production in the skin which eventually leads to DNA damage and mutation. Various delivery approaches for the skin cancer treatment/prevention have been evolving and are directed toward improvements in terms of delivery modes, therapeutic agents, and site-specificity of therapeutics delivery. The effective chemoprevention activity achieved is based on the efficiency of the delivery system used and the amount of the therapeutic molecule deposited in the skin. In this article, we have discussed different studies performed specifically for the chemoprevention of UVB-induced skin cancer. Ultra-flexible nanocarriers, transethosomes nanocarriers, silica nanoparticles, silver nanoparticles, nanocapsule suspensions, microemulsion, nanoemulsion, and polymeric nanoparticles which have been used so far to deliver the desired drug molecule for preventing the UVB-induced skin cancer.

Honokiol nanomicellar formulation produced increased oral bioavailability and anticancer effects in triple negative breast cancer (TNBC)

Triple negative breast cancer (TNBC), owing to its aggressive behavior and toxicity associated with available chemotherapy; currently no suitable therapy is available. Honokiol (HNK) is a promising anticancer drug but has poor bioavailability. In the current study, we evaluated the anticancer effects of an oral Honokiol nanomicellar (NM) formulation (size range of 20-40nm) in vitro against various TNBC cells lines. Cytotoxicity, clonogenic and wound healing assays demonstrated the promising anticancer effects. In vitro Caco-2 permeability studies suggested increased absorption of Honokiol. Compared to HNK-FD, nanomicellar formulations resulted in significant increase in the oral bioavailability. C_max (4.06 and 3.60-fold) and AUC (6.26 and 5.83-fold) were significantly increased in comparison to oral 40 and 80mg/kg free drug respectively. Further, anticancer effects of these formulations were studied in BALB/c nude mice transplanted with orthotopic MDA-MB-231 cell induced xenografts. After 4 weeks of daily administration of HNK-NM formulation, significant reduction in the tumor volumes and weights compared to free drug (p<0.001) treated groups was observed. Surprisingly, in some of the animals (25%), the treatment resulted in complete eradication of tumors. Increased apoptosis and antiangiogenic effect was observed in HNK-NM groups compared to free drug and untreated control animals. This is the first report demonstrating that HNK-FD possesses anticancer effects against TNBC.

Nuclear receptor function in skin health and disease: therapeutic opportunities in the orphan and adopted receptor classes

The skin forms a vital barrier between an organism's external environment, providing protection from pathogens and numerous physical and chemical threats. Moreover, the intact barrier is essential to prevent water and electrolyte loss without which terrestrial life could not be maintained. Accordingly, acute disruption of the skin through physical or chemical trauma needs to be repaired timely and efficiently as sustained skin pathologies ranging from mild irritations and inflammation through to malignancy impact considerably on morbidity and mortality. The Nuclear Hormone Receptor Family of transcriptional regulators has proven to be highly valuable targets for addressing a range of pathologies, including metabolic syndrome and cancer. Indeed members of the classic endocrine sub-group, such as the glucocorticoid, retinoid, and Vitamin D receptors, represent mainstay treatment strategies for numerous inflammatory skin disorders, though side effects from prolonged use are common. Emerging evidence has now highlighted important functional roles for nuclear receptors belonging to the adopted and orphan subgroups in skin physiology and patho-physiology. This review will focus on these subgroups and explore the current evidence that suggests these nuclear receptor hold great promise as future stand-alone or complementary drug targets in treating common skin diseases and maintaining skin homeostasis.

Novel diindolylmethane derivatives based NLC formulations to improve the oral bioavailability and anticancer effects in triple negative breast cancer

The present study demonstrates the promising anticancer effects of novel C-substituted diindolylmethane (DIM) derivatives DIM-10 and DIM-14 in aggressive TNBC models. In vitro studies demonstrated that these compounds possess strong anticancer effects. Caco-2 permeability studies resulted in poor permeability and poor oral bioavailability was demonstrated by pharmacokinetic studies. Nano structured lipid carrier (NLC) formulations were prepared to increase the clinical acceptance of these compounds. Significant increase in oral bioavailability was observed with NLC formulations. Compared to DIM-10, DIM-10 NLC formulation showed increase in C_max and AUC values by 4.73 and 11.19-folds, respectively. Similar pattern of increase was observed with DIM-14 NLC formulations. In dogs DIM-10 NLC formulations showed an increase of 2.65 and 2.94-fold in C_max and AUC, respectively. The anticancer studies in MDA-MB-231 orthotopic TNBC models demonstrated significant reduction in tumor volumes in DIM-10 and DIM-14 NLC treated animals. Our studies suggest that NLC formulation of both DIM-10 and 14 is effective in TNBC models.

Lipid-based oral delivery systems for skin deposition of a potential chemopreventive DIM derivative: characterization and evaluation

The objective of this study was to explore the oral route as a viable potential for the skin deposition of a novel diindolylmethane derivative (DIM-D) for chemoprevention activity. Various lipid-based oral delivery systems were optimized and compared for enhancing DIM-D's oral bioavailability and skin deposition. Preformulation studies were performed to evaluate the log P and solubility of DIM-D. Microsomal metabolism, P-glycoprotein efflux, and caco-2 monolayer permeability of DIM-D were determined. Comparative evaluation of the oral absorption and skin deposition of DIM-D-loaded various lipid-based formulations was performed in rats. DIM-D showed pH-dependent solubility and a high log P value. It was not a strong substrate of microsomal degradation and P-glycoprotein. SMEDDs comprised of medium chain triglycerides, monoglycerides, and kolliphor-HS15 (36.70 ± 0.42 nm). SNEDDs comprised of long chain triglycerides, cremophor RH40, labrasol, and TPGS (84.00 ± 14.14 nm). Nanostructured lipid carriers (NLC) consisted of compritol, miglyol, and surfactants (116.50 ± 2.12 nm). The blank formulations all showed >70 % cell viability in caco-2 cells. Differential Scanning Calorimetry confirmed the amorphization of DIM-D within the lipid matrices while Atomic Force Microscopy showed particle size distribution similar to the dynamic light scattering data. DIM-D also showed reduced permeation across caco-2 monolayer that was enhanced (p < 0.05) by SNEDDs in comparison to SMEDDs and NLC. Fabsolute for DIM-D SNEDDs, SMEDDs, and NLC was 0.14, 0.04, and 0.007, respectively. SNEDDs caused 53.90, 11.32, and 15.08-fold more skin deposition of DIM-D than the free drug, SMEDDs, and NLC, respectively, at 2 h following oral administration and shows a viable potential for use in skin cancer chemoprevention. Graphical Abstract ᅟ.

Ultra-flexible nanocarriers for enhanced topical delivery of a highly lipophilic antioxidative molecule for skin cancer chemoprevention

PURPOSE

In this study, we developed cationic ultra-flexible nanocarriers (UltraFLEX-Nano) to surmount the skin barrier structure and to potentiate the topical delivery of a highly lipophilic antioxidative diindolylmethane derivative (DIM-D) for the inhibition of UV-induced DNA damage and skin carcinogenesis.

METHODS

UltraFLEX-Nano was prepared with 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, 1,2-dioleoyl-3-trimethylammonium-propane, cholesterol and tween-80 by ethanolic injection method; was characterized by Differential Scanning Calorimetric (DSC), Fourier Transform Infrared (FT-IR) and Atomic Force Microscopic (phase-imaging) analyses and permeation studies were performed in dermatomed human skin. The efficacy of DIM-D-UltraFLEX-Nano for skin cancer chemoprevention was evaluated in UVB-induced skin cancer model in vivo.

RESULTS

DIM-D-UltraFLEX-Nano formed a stable mono-dispersion (110.50±0.71nm) with >90% encapsulation of DIM-D that was supported by HPLC, DSC, FT-IR and AFM phase imaging. The blank formulation was non-toxic to human embryonic kidney cells. UltraFLEX-Nano was vastly deformable and highly permeable across the stratum corneum; there was significant (p<0.01) skin deposition of DIM-D for UltraFLEX-Nano that was superior to PEG solution (13.83-fold). DIM-D-UltraFLEX-Nano pretreatment delayed the onset of UVB-induced tumorigenesis (2 weeks) and reduced (p<0.05) the number of tumors observed in SKH-1 mice (3.33-fold), which was comparable to pretreatment with sunscreen (SPF30). Also, DIM-D-UltraFLEX-Nano caused decrease (p<0.05) in UV-induced DNA damage (8-hydroxydeoxyguanosine), skin inflammation (PCNA), epidermal hyperplasia (c-myc, CyclinD1), immunosuppression (IL10), cell survival (AKT), metastasis (Vimentin, MMP-9, TIMP1) but increase in apoptosis (p53 and p21).

CONCLUSION

UltraFLEX-Nano was efficient in enhancing the topical delivery of DIM-D. DIM-D-UltraFLEX-Nano was efficacious in delaying skin tumor incidence and multiplicity in SKH mice comparable to sunscreen (SPF30).

Novel Gefitinib Formulation with Improved Oral Bioavailability in Treatment of A431 Skin Carcinoma

PURPOSE

Oral administration of anticancer agents presents a series of advantages for patients. However, most of the anticancer drugs have poor water solubility leading to low bioavailability.

METHODS

Controlled released spray dried matrix system of Gefitinib with hydroxypropyl β-cyclodextrin, chitosan, hydroxy propyl methyl cellulose, vitamin E TPGS, succinic acid were used for the design of formulations to improve the oral absorption of Gefitinib. Spray drying with a customized spray gun which allows simultaneous/pulsatile flow of two different liquid systems through single nozzle was used to prepare Gefitinib spray dried formulations (Gef-SD). Formulation was characterized by in vitro drug release and Caco-2 permeability studies. Pharmacokinetic studies were performed in Sprague Dawley rats. Efficacy of Gef-SD was carried out in A431 xenografts models in nude mice.

RESULTS

In Gef-SD group 9.14-fold increase in the AUC was observed compared to free Gef. Improved pharmacokinetic profile of Gef-SD translated into increase (1.75 fold compared to Gef free drug) in anticancer effects. Animal survival was significantly increased in Gef formulation treated groups, with superior reduction in the tumor size (1.48-fold) and volumes (1.75-fold) and also increase in the anticancer effects (TUNEL positive apoptotic cells) was observed in Gef-SD treated groups. Further, western blot, immunohistochemical and proteomics analysis demonstrated the increased pharmacodynamic effects of Gef-SD formulations in A431 xenograft tumor models.

CONCLUSION

Our studies suggested that Gefitinib can be successfully incorporated into control release microparticles based oral formulation with enhanced pharmacokinetic and pharmacodynamic activity. This study demonstrates the novel application of Gef in A431 tumor models.

A novel synthetic activator of Nurr1 induces dopaminergic gene expression and protects against 6-hydroxydopamine neurotoxicity in vitro

Degeneration of dopaminergic neurons in Parkinson's disease (PD) is associated with decreased expression of the orphan nuclear receptor Nurr1 (NR4A2), which is critical for both homeostasis and development of dopamine (DA) neurons. The synthetic, phytochemical-based compound, 1,1-bis (3'-indolyl)-1-(p-chlorophenyl) methane (C-DIM12) activates Nurr1 in cancer cells and prevents loss of dopaminergic neurons in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of PD in mice. In the present study, we examined the capacity of C-DIM12 to induce expression of Nurr1-regulated genes in two dopaminergic neuronal cell lines (N2A, N27) and to protect against 6-hydroxydopamine (6-OHDA) neurotoxicity. C-DIM12 induced expression of Nurr1-regulated genes that was abolished by Nurr1 knockdown. C-DIM12 increased expression of transfected human Nurr1, induced Nurr1 protein expression in primary dopaminergic neurons and enhanced neuronal survival from exposure to 6-OHDA. These data indicate that C-DIM12 stimulates neuroprotective expression Nurr1-regulated genes in DA neurons.

Clinicopathological significance of orphan nuclear receptor Nurr1 expression in gastric cancer

BACKGROUND

Gastric cancer is the fourth most common cancer and the second leading cause of cancer-related deaths worldwide. Gastric cancer is characterized by high levels of invasion and metastasis. Increasing attention is being focused on discovering molecular markers for the diagnosis of gastric cancer and for predicting its prognosis. The objective of the present study was to evaluate Nurr1 expression in gastric cancer and to assess its correlation with clinicopathological parameters and prognosis in gastric cancer patients.

METHODS

Tissue samples were obtained from 120 gastric cancer patients. We investigated Nurr1 expression in human normal and gastric cancer tissues using real-time reverse transcription polymerase chain reaction (qRT-PCR), western blotting, and immunohistochemistry. We determined the association between Nurr1 and recurrence, prognosis and patient clinicopathological parameters. Univariate and multivariate survival analyses with a Cox's proportional hazards regression model were used to identify independent factors related to recurrence and prognosis.

RESULTS

The immunohistochemical, qRT-PCR and western blot analyses revealed that Nurr1 expression was increased in gastric cancer tissues compared with normal gastric tissue (P < 0.05). Nurr1 expression was significantly correlated with the tumor size, depth of tumor invasion, lymph node metastasis, recurrence, and distant metastasis of gastric cancer (P < 0.05). Moreover, Nurr1-high patients also exhibited poorer overall survival (OS) and disease-free survival compared with Nurr1-low patients (P < 0.01). The univariate and multivariate survival analyses suggested that Nurr1 expression (P = 0.011), histology (P = 0.018), depth of tumor invasion (P = 0.037), and presence of lymph node metastasis (P = 0.031) were independent prognostic factors for recurrence. In addition, Nurr1 expression (P = 0.007), depth of tumor invasion (P = 0.014), lymph node metastasis (P = 0.044), distant metastasis (P = 0.023), and recurrence (P = 0.011) were independent prognostic factors of OS in gastric cancer patients.

CONCLUSIONS

The Nurr1 protein may be useful as a marker of recurrence, metastasis, and poor prognosis following curative resection in patients with gastric cancer.

MC1R and NR4A receptors in cellular stress and DNA repair: implications for UVR protection

Ultraviolet radiation (UVR) is the most common mutagen that melanocytes are exposed to. UVR causes a diverse range of DNA photolesions contributing to genome instability and promotes melanoma and non-melanoma development. Melanocytes are pigment-producing cells that synthesise the photoprotective melanins when the melanocortin-1 receptor (MC1R) is activated. MC1R is a G-protein-coupled receptor expressed predominantly in melanocytes. Its signalling pathway has been directly linked to melanogenesis, enhanced cytoprotection against UV damage and augmented DNA repair response. Interestingly, previous studies have revealed that MC1R signalling induces the transcription of the NR4A subfamily of orphan nuclear receptors in response to UV. In line with this, studies have also observed that NR4A receptors are recruited to distinct nuclear foci in response to cellular stress, independent of their transcriptional roles. Here, we review the regulated expression of NR4A2 and its potential roles upon cellular stress conditions. Current work in developing synthetic NR4A2 agonists further provides exciting avenues for exploring the potential role of NR4A2 as an antiskin cancer drug target.