Nanoquinacrine induced apoptosis in cervical cancer stem cells through the inhibition of hedgehog-GLI1 cascade: Role of GLI-1

Identification of Novel GANT61 Analogs with Activity in Hedgehog Functional Assays and GLI1-Dependent Cancer Cells

Aberrant activation of hedgehog (Hh) signaling has been implicated in various cancers. Current FDA-approved inhibitors target the seven-transmembrane receptor Smoothened, but resistance to these drugs has been observed. It has been proposed that a more promising strategy to target this pathway is at the GLI1 transcription factor level. GANT61 was the first small molecule identified to directly suppress GLI-mediated activity; however, its development as a potential anti-cancer agent has been hindered by its modest activity and aqueous chemical instability. Our study aimed to identify novel GLI1 inhibitors. JChem searches identified fifty-two compounds similar to GANT61 and its active metabolite, GANT61-D. We combined high-throughput cell-based assays and molecular docking to evaluate these analogs. Five of the fifty-two GANT61 analogs inhibited activity in Hh-responsive C3H10T1/2 and Gli-reporter NIH3T3 cellular assays without cytotoxicity. Two of the GANT61 analogs, BAS 07019774 and Z27610715, reduced Gli1 mRNA expression in C3H10T1/2 cells. Treatment with BAS 07019774 significantly reduced cell viability in Hh-dependent glioblastoma and lung cancer cell lines. Molecular docking indicated that BAS 07019774 is predicted to bind to the ZF4 region of GLI1, potentially interfering with its ability to bind DNA. Our findings show promise in developing more effective and potent GLI inhibitors.

Targeting Cervical Cancer Stem Cells by Phytochemicals

Cervical cancer (CaCx) poses a significant global health challenge, ranking as the fourth most common cancer among women worldwide. Despite the emergence of advanced treatment strategies, recurrence remains a bottleneck in favorable treatment outcomes and contributes to poor prognosis. The chemo- or radio-therapy resistance coupled with frequent relapse of more aggressive tumors are some key components that contribute to CaCx-related mortality. The onset of therapy resistance and relapse are attributed to a small subset of, slow-proliferating Cancer Stem Cells (CSC). These CSCs possess the properties of tumorigenesis, self-renewal, and multi-lineage differentiation potential. Because of slow cycling, these cells maintain themselves in a semi-quiescent stage and protect themselves from different anti-proliferative anti-cancer drugs. Keeping in view recent advances in their phenotypic and functional characterization, the feasibility of targeting CSC and associated stem cell signaling bears a strong translational value. The presence of CSC has been reported in CaCx (CCSC) which remains a forefront area of research. However, we have yet to identify clinically useful leads that can target CCSC. There is compelling evidence that phytochemicals, because of their advantages over synthetic anticancer drugs, could emerge as potential therapeutic leads to target these CCSCs. The present article examined the potential of phytochemicals with reported anti-CSC properties and evaluated their future in preclinical and clinical applications against CaCx.

Talazoparib enhances the quinacrine-mediated apoptosis in patient-derived oral mucosa CSCs by inhibiting BER pathway through the modulation of GCN5 and P300

The presence of cancer stem cells (CSCs) in the tumor microenvironment (TME) is majorly responsible for the development and recurrence of cancer. Earlier reports suggested that upon DNA damage, poly-(ADP-ribose) polymerase-1 (PARP-1) helps in chromatin modulation and DNA repair process, thereby promoting CSC survival. But whether a combination of DNA damaging agents along with PARP inhibitors can modulate chromatin assembly, inhibit DNA repair processes, and subsequently target CSCs is not known. Hence, we have investigated the effect of nontoxic bioactive compound quinacrine (QC) and a potent PARP inhibitor Talazoparib in patient-derived oral mucosa CSCs (OM-CSCs) and in vivo xenograft mice preclinical model systems. Data showed that QC + Talazoparib inhibited the PARP-1-mediated chromatin remodelers' recruitment and deregulated HAT activity of GCN5 (general control nonderepressible-5) and P300 at DNA damage site, thereby preventing the access of repair proteins to the damaged DNA. Additionally, this combination treatment inhibited topoisomerase activity, induced topological stress, and induced apoptosis in OM-CSCs. Similar results were observed in an in vivo xenograft mice model system. Collectively, the data suggested that QC + Talazoparib treatment inhibited BER pathway, induced genomic instability and triggered apoptosis in OM-CSCs through the deregulation of PARP-1-mediated chromatin remodelers (GCN5 and P300) activity. Schematic representation of QC + Talazoparib-induced apoptosis in oral mucosa CSCs. (1) Induction of DNA damage takes place after QC treatment (2) PARP1-mediated PARylation at the site of DNA damage, which recruits multiple chromatin remodelers (3) Acetylation at the histone tails relax the structure of chromatin and recruits the BER pathway proteins at the site of DNA damage. (4) BER pathway activated at the site of DNA damage. (5) CSCs survive after successful repair of DNA damage. (6) Treatment of QC-treated CSCs with PARP inhibitor Talazoparib (7) Inhibition of PARylation results in failure of chromatin remodelers to interact with PARP1. (8) Inhibition of acetylation status leads to chromatin compaction. (9) BER pathway proteins are not recruited at the site of DNA damage, resulting in inhibition of BER pathway and accumulation of unrepaired DNA damage, leading to apoptosis and cell death.

Role of non-coding RNAs in neuroblastoma

Neuroblastoma is known as the most prevalent extracranial malignancy in childhood with a neural crest origin. It has been widely accepted that non-coding RNAs (ncRNAs) play important roles in many types of cancer, including glioma and gastrointestinal cancers. They may regulate the cancer gene network. According to recent sequencing and profiling studies, ncRNAs genes are deregulated in human cancers via deletion, amplification, abnormal epigenetic, or transcriptional regulation. Disturbances in the expression of ncRNAs may act either as oncogenes or as anti-tumor suppressor genes, and can lead to the induction of cancer hallmarks. ncRNAs can be secreted from tumor cells inside exosomes, where they can be transferred to other cells to affect their function. However, these topics still need more study to clarify their exact roles, so the present review addresses different roles and functions of ncRNAs in neuroblastoma.

Epigenetic control of cell signalling in cancer stem cells

The self-renewing cancer stem cells (CSCs) represent one of the distinct cell populations occurring in a tumour that can differentiate into multiple lineages. This group of sparsely abundant cells play a vital role in tumour survival and resistance to different treatments during cancer. The lack of exclusive markers associated with CSCs makes diagnosis and prognosis in cancer patients extremely difficult. This calls for the identification of unique regulators and markers for CSCs. Various signalling pathways like the Wnt/β-catenin pathway, Hedgehog pathway, Notch pathway, and TGFβ/BMP play a major role in the regulation and maintenance of CSCs. Epigenetic regulatory mechanisms add another layer of complexity to control these signalling pathways. In this chapter, we discuss about the role of epigenetic mechanisms in regulating the cellular signalling pathways in CSCs. The epigenetic regulatory mechanisms such as DNA methylation, histone modification and microRNAs can modulate the diverse effectors of signalling pathways and consequently the growth, differentiation and tumorigenicity of CSCs. In the end, we briefly discuss the therapeutic potential of targeting these epigenetic regulators and their target genes in CSCs.

Circular RNAs in neuroblastoma: Pathogenesis, potential biomarker, and therapeutic target

Neuroblastoma (NB) is a common cancer in childhood responsible for 15 % of fatalities by pediatric cancers. Epigenetic factors play an important role in the pathogenesis of NB. Recently, it has been demonstrated that circular RNAs (circRNAs, ciRNAs), a newly identified class of non-coding RNAs, are also dysregulated in NB. CircRNAs mediate their functions by regulating gene expression mainly through microRNA (miRNA) sponging. The dysregulation (abnormal upregulation or downregulation) of circRNAs is involved in tumorigenesis of a variety of tumors including NB. It seems that the expression of some circRNAs is correlated with NB prognosis and clinical features. CircRNAs might be favorable as a diagnostic/prognostic biomarker and therapeutic target. However, due to the lack of studies, it is difficult to make a conclusion regarding the clinical benefits of circRNAs. In this review, we discussed the circRNAs that experimentally have been proved to be dysregulated in NB tissues and cancer cells.

Repurposing of Anti-Malarial Drug Quinacrine for Cancer Treatment: A Review

Quinacrine (QC), a synthetic drug belonging to the 9-aminoacridine family, has been used extensively to treat malaria and multiple ailments over the past several decades. Following its discovery in the 1920s and extensive use for the treatment of malaria for nearly two decades, numerous studies have explored its antineoplastic potential in both preclinical and clinical settings. Multiple studies spanning over seven decades have examined a wide range of QC anticancer activities across various types of cancers, along with the underlying mechanisms. Many of these mechanisms, including activation of the p53 signaling cascade and simultaneous NF-κB signaling inhibition, have been reported in various studies, bringing QC to a unique polypharmacological category drug possessing the potential to treat a wide variety of diseases, including cancer. This article summarizes most of the research conducted over several decades to uncover new molecular mechanisms activated or inactivated and directly correlate with antineoplastic activity QC.

PARP inhibitor BMN-673 induced apoptosis by trapping PARP-1 and inhibiting base excision repair via modulation of pol-β in chromatin of breast cancer cells

PARP inhibitors emerged as clinically effective anti-tumor agents in combination with DNA damaging agents but the toxicity of DNA damaging agents and their off-target effects caused serious problems in cancer therapy. They confer cytotoxicity in cancer cells both by catalytic inhibition and trapping of PARP-1 at the DNA damage site. There is a lack of direct evidence to quantitatively determine the trapped PARP-1 in cellular DNA. Here, we have precisely evaluated the mechanism of PARP trapping mediated anti-cancer action of Quinacrine (QC), BMN-673, and their combination (QC + BMN-673) in breast cancer cells. We introduced a strategy to measure the cellular PARP trapping potentiality of BMN-673 in QC pretreated cells using a fluorescence-based assay system. It was found that QC+ BMN-673 induced apoptosis by triggering DNA damage in breast cancer cells. Treatment with QC + BMN-673 stimulated the expression of PARP-1 in the chromatin compared to that of PARP-2 and PARP-3. QC + BMN-673 treatment also caused a dose-dependent and time-dependent accumulation of PARP-1 and inhibition of PARylation in the chromatin. Upregulation of BER components (pol-β and FEN-1), an unchanged HR and NHEJ pathway proteins, and reduction of luciferase activity of the cells transfected with R-p21-P (LP-BER) were noted in combined drug-treated cells. Interestingly, silencing of pol-β resulted in unchanged PARP-1 trapping and PAR activity in the chromatin with increasing time after QC + BMN-673 treatment without altering APC and FEN-1 expression. Thus, our data suggested that the QC + BMN-673 augmented breast cancer cell death by pol-β mediated repair inhibition primarily through trapping of PARP-1 besides PARP-1 catalytic inhibition.

Mechanisms of Drug Resistance and Use of Nanoparticle Delivery to Overcome Resistance in Breast Cancers

Breast cancer is the leading cancer type diagnosed among women in the world. Unfortunately, drug resistance to current breast cancer chemotherapeutics remains the main challenge for a higher survival rate. The recent progress in the nanoparticle platforms and distinct features of nanoparticles that enhance the efficacy of therapeutic agents, such as improved delivery efficacy, increased intracellular cytotoxicity, and reduced side effects, hold great promise to overcome the observed drug resistance. Currently, multifaceted investigations are probing the resistance mechanisms associated with clinical drugs, and identifying new breast cancer-associated molecular targets that may lead to improved therapeutic approaches with the nanoparticle platforms. Nanoparticle platforms including siRNA, antibody-specific targeting and the role of nanoparticles in cellular processes and their effect on breast cancer were discussed in this article.

Insight into the role of multiple signaling pathways in regulating cancer stem cells of gynecologic cancers

Mounting evidence has demonstrated that a myriad of developmental signaling pathways, such as the Wnt, Notch, Hedgehog and Hippo, are frequently deregulated and play a critical role in regulating cancer stem cell (CSC) activity in human cancers, including gynecologic malignancies. In this review article, we describe an overview of various signaling pathways in human cancers. We further discuss the developmental roles how these pathways regulate CSCs from experimental evidences in gynecologic cancers. Moreover, we mention several compounds targeting CSCs in gynecologic cancers to enhance the treatment outcomes. Therefore, these signaling pathways might be the potential targets for developing targeted therapy in gynecologic cancers.

Nano formulated Resveratrol inhibits metastasis and angiogenesis by reducing inflammatory cytokines in oral cancer cells by targeting tumor associated macrophages

Tumor associated macrophages in the tumor microenvironment secrete multiple cytokines, which regulate cancer cells growth and invasiveness. We systematically studied the role of cytokines in the induction of cancer stem like cells (CSCs) in oral cancer cells niche and evaluated the mechanism of Resveratrol nanoparticle (Res-Nano) mediated-reduction of CSCs properties in cells. A highly M1-like macrophages-enriched conditioned medium (CM) was generated by treating fixed doses of PMA and LPS in THP-1 cells alone as well as co-cultured of H-357 plus THP-1 cells. These M1-like macrophages increased the production of cytokines (e.g., TNF-α, IL-6, IL-1β, etc.). A CSCs populated environment was created after addition of cytokine-enriched-CM of co-culture of H-357 and THP-1 cells to cancer cells and cytokine enriched CM of THP-1 cells to patient derived primary oral cancer cells, respectively. After incubation with CM, enhancement of stemness, angiogenic and metastatic properties of both H-357 and primary oral cancer cells were noted. Res-NP decreased the cytokines level in CSCs-enriched cells and reduced the invasion, proliferation and growth of CSCs. Representative metastatic (CD133, ALDH1, CXCR4, etc.) and angiogenic markers (MMPs, iNOS, VEGF-A, etc.) were decreased after Res-NP treatment in CSCs enriched oral cancer cells niche. It also disrupted angiogenesis, depleted nitric oxide production in fertilized chick embryos and reduced the expression of metastatic and angiogenic markers in xenograft mice model system. Thus, this study concluded that CSCs-mediated stemness is a cytokine dependent phenomena and treatment of Res-NP inhibit this process in in vitro, in vivo and ex vivo systems.

Anti-Cancer Stem Cells Potentiality of an Anti-Malarial Agent Quinacrine: An Old Wine in a New Bottle

Quinacrine (QC) is a tricyclic compound and a derivative of 9-aminoacridine. It has been widely used to treat malaria and other parasitic diseases since the last century. Interestingly, studies have revealed that it also displays anti-cancer activities. Here, we have discussed the anti-cancer mechanism of QC along with its potentiality to specifically target cancer stem cells. The anti-cancer action of this drug includes DNA intercalation, inhibition of DNA repair mechanism, prevention of cellular growth, cell cycle arrest, inhibition of DNA and RNA polymerase activity, induction of autophagy, promotion of apoptosis, deregulation of cell signaling in cancer cells and cancer stem cells, inhibition of metastasis and angiogenesis. In addition, we have also emphasized on the synergistic effect of this drug with other potent chemotherapeutic agents and mentioned its different applications in anti-cancer therapy.

Undaria pinnatifida fucoidan nanoparticles loaded with quinacrine attenuate growth and metastasis of pancreatic cancer

Pancreatic cancer is a devastating gastrointestinal tumor with limited Chemotherapeutic options. Treatment is restricted by its poor vascularity and dense surrounding stroma. Quinacrine is a repositioned drug with an anticancer activity but suffers a limited ability to reach tumor cells. This could be enhanced using nanotechnology by the preparation of quinacrine-loaded Undaria pinnatifida fucoidan nanoparticles. The system exploited fucoidan as both a delivery system of natural origin and active targeting ligand. Lactoferrin was added as a second active targeting ligand. Single and dual-targeted particles prepared through nanoprecipitation and ionic interaction respectively were appraised. Both particles showed a size lower than 200 nm, entrapment efficiency of 80% and a pH-dependent release of the drug in the acidic environment of the tumor. The anticancer activity of quinacrine was enhanced by 5.7 folds in dual targeted particles compared to drug solution with a higher ability to inhibit migration and invasion of cancer. In vivo, these particles showed a 68% reduction in tumor volume compared to only 20% for drug solution. In addition, they showed a higher animals' survival rate with no hepatotoxicity. Hence, these particles could be an effective option for the eradication of pancreatic cancer cells.

Regulation of Hedgehog Signaling by miRNAs and Nanoformulations: A Possible Therapeutic Solution for Colorectal Cancer

Hedgehog (Hh) signaling aberrations trigger differentiation and proliferation in colorectal cancer (CRC). However, the current approaches which inhibit this vital cellular pathway provoke some side effects. Therefore, it is necessary to look for new therapeutic options. MicroRNAs are small molecules that modulate expression of the target genes and can be utilized as a potential therapeutic option for CRC. On the other hand, nanoformulations have been implemented in the treatment of plethora of diseases. Owing to their excessive bioavailability, limited cytotoxicity and high specificity, nanoparticles may be considered as an alternative drug delivery platform for the Hh signaling mediated CRC. This article reviews the Hh signaling and its involvement in CRC with focus on miRNAs, nanoformulations as potential diagnostic/prognostic and therapeutics for CRC.

Nanoformulated quinacrine regulates NECTIN-4 domain specific functions in cervical cancer stem cells

NECTIN-4 [a poliovirus receptor-related-4 (PVRL-4) encoded gene] has vital roles in cancer proliferation, metastasis and angiogenesis. It possesses three different domains and it is predicted that they have different roles in cancer but the structure-function relationship is still unknown and hence carrying out a detailed study to elucidate the domain-specific functions of NECTIN-4 in cancer is necessary. Using 5-Fluouracil-resistant cervical cancer stem cells (PEMT-5FU-R-MC) and different NECTIN-4 domain-specific constructs, different domains of NECTIN-4 were over-expressed in PEMT-5FU-R-MC cells. Biochemical assays like comet, γ-H2AX immunofluorescence, western blot, in vitro tube formation, gelatin zymography, in ovo CAM assay, etc. were used to delineate the function of each domain of NECTIN-4 in cancer and their regulation by nano-formulated quinacrine (NQC). Endo-domain (lacking extracellular region corresponding to aa 30-347) and ecto-domain (lacking signal peptide and cytoplasmic region corresponding to aa 1-29 and 348-509, respectively) of NECTIN-4 were largely overexpressed in nucleus and cytoplasm, respectively. Endo-domain translocates into nucleus by physically interacting with IMPORTIN-α2, activates the DNA repair and enhances cell growth, whereas ecto-domain specifically activates angiogenesis by modulating representative angiogenic markers, inducing in vitro tube formation and in ovo blood vessel formation. Full-length NECTIN-4 (aa 1-509) was overexpressed in both nucleus and cytoplasm and modulated both DNA repair and angiogenesis. NQC down-regulated these phenomena by modulating the endo-domain and ecto-domain of NECTIN-4. Thus, current study suggested that endo-domain of NECTIN-4 translocated into nucleus and increased the DNA repair and ecto-domain of NECTIN-4 enhanced the angiogenesis, whereas NQC inhibits these processes.

Tumour suppressor 15-hydroxyprostaglandin dehydrogenase induces differentiation in colon cancer via GLI1 inhibition

Inflammation is an established risk factor for colorectal cancer. We and others have shown that colorectal cancer patients with elevated cysteinyl leukotriene receptor 2 (CysLT₂R) and 15-hydroxyprostaglandin dehydrogenase (15-PGDH) levels exhibit good prognoses. However, both CysLT₂R and 15-PGDH, which act as tumour suppressors, are often suppressed in colorectal cancer. We previously reported that leukotriene C₄ (LTC₄)-induced differentiation in colon cancer via CysLT₂R signalling. Here, we investigated the involvement of Hedgehog (Hh)-GLI1 signalling, which is often hyperactivated in colorectal cancer. We found that the majority of colorectal cancer patients had high-GLI1 expression, which was negatively correlated with CysLT₂R, 15-PGDH, and Mucin-2 and overall survival compared with the low-GLI1 group. LTC₄-induced 15-PGDH downregulated both the mRNA and protein expression of GLI1 in a protein kinase A (PKA)-dependent manner. Interestingly, the LTC₄-induced increase in differentiation markers and reduction in Wnt targets remained unaltered in GLI1-knockdown cells. The restoration of GLI1 in 15-PGDH-knockdown cells did not ameliorate the LTC₄-induced effects, indicating the importance of both 15-PGDH and GLI1. LTC₄-mediated reduction in the DCLK1 and LGR5 stemness markers in colonospheres was abolished in cells lacking 15-PGDH or GLI1. Both DCLK1 and LGR5 were highly increased in tumour tissue compared with the matched controls. Reduced Mucin-2 levels were observed both in zebrafish xenografts with GLI1-knockdown cells and in the cysltr2^-/- colitis-associated colon cancer (CAC) mouse model. Furthermore, GLI1 expression was positively correlated with stemness and negatively correlated with differentiation in CRC patients when comparing tumour and mucosal tissues. In conclusion, restoring 15-PGDH expression via CysLT₂R activation might benefit colorectal cancer patients.

Cancer Stem Cells: Acquisition, Characteristics, Therapeutic Implications, Targeting Strategies and Future Prospects

Since last two decades, the major cancer research has focused on understanding the characteristic properties and mechanism of formation of Cancer stem cells (CSCs), due to their ability to initiate tumor growth, self-renewal property and multi-drug resistance. The discovery of the mechanism of acquisition of stem-like properties by carcinoma cells via epithelial-mesenchymal transition (EMT) has paved a way towards a deeper understanding of CSCs and presented a possible avenue for the development of therapeutic strategies. In spite of years of research, various challenges, such as identification of CSC subpopulation, lack of appropriate experimental models, targeting cancer cells and CSCs specifically without harming normal cells, are being faced while dealing with CSCs. Here, we discuss the biology and characteristics of CSCs, mode of acquisition of stemness (via EMT) and development of multi-drug resistance, the role of tumor niche, the process of dissemination and metastasis, therapeutic implications of CSCs and necessity of targeting them. We emphasise various strategies being developed to specifically target CSCs, including those targeting biomarkers, key pathways and microenvironment. Finally, we focus on the challenges that need to be subdued and propose the aspects that need to be addressed in future studies in order to broaden the understanding of CSCs and develop novel strategies to eradicate them in clinical applications. Graphical Abstract Cancer Stem Cells(CSCs) have gained much attention in the last few decades due to their ability to initiate tumor growth and, self-renewal property and multi-drug resistance. Here, we represent the CSC model of cancer, Characteristics of CSCs, acquisition of stemness and metastatic dissemination of cancer, Therapeutic implications of CSCs and Various strategies being employed to target and eradicate CSCs.

Circular RNA DGKB Promotes the Progression of Neuroblastoma by Targeting miR-873/GLI1 Axis

Accumulated evidences suggested that circular RNAs (circRNA) played critical roles in tumorigenesis and progression. To our knowledge, no study reported the function of circular RNA DGKB (circDGKB, circRNA ID: hsa_circ_0133622) on progression of neuroblastoma (NB). Here, we showed that circDGKB was upregulated in NB tissues compared to the normal dorsal root ganglia. Moreover, the expression level of circDGKB was negatively correlated with the survival rate of NB patients. Mechanically, overexpression of circDGKB promoted the proliferation, migration, invasion, and tumorigenesis of NB cells and reduced cell apoptosis, and vice versa. In addition, qRT-PCR and/or Western blot results showed that circDGKB overexpression inhibited the expression level of miR-873 and enhanced GLI1 expression. Moreover, miR-873 functioned an opposite role to circDGKB and significantly weakened circDGKB role in promoting NB progression. Furthermore, GLI1 upregulation also rescued the miR-873 role in inhibiting NB progression. In conclusion, our work proved that circDGKB promoted NB progression via targeting miR-873/GLI1 axis in vitro and in vivo. Our study provided a new target for NB treatment and indicated that circDGKB could act as a novel diagnostic marker for NB.

Nanoparticles for Manipulation of the Developmental Wnt, Hedgehog, and Notch Signaling Pathways in Cancer

The Wnt, Hedgehog, and Notch signaling pathways play a crucial role in early development and the maintenance of adult tissues. When dysregulated, these developmental signaling pathways can drive the formation and progression of cancer by facilitating cell survival, proliferation, and stem-like behavior. While this makes these pathways promising targets for therapeutic intervention, their pharmacological inhibition has been challenging due to the substantial complexity that exists within each pathway and the complicated crosstalk that occurs between the pathways. Recently, several small molecule inhibitors, ribonucleic acid (RNA) molecules, and antagonistic antibodies have been developed that can suppress these signaling pathways in vitro, but many of them face systemic delivery challenges. Nanoparticle-based delivery vehicles can overcome these challenges to enhance the performance and anti-cancer effects of these therapeutic molecules. This review summarizes the mechanisms by which the Wnt, Hedgehog, and Notch signaling pathways contribute to cancer growth, and discusses various nanoparticle formulations that have been developed to deliver small molecules, RNAs, and antibodies to cancer cells to inhibit these signaling pathways and halt tumor progression. This review also outlines some of the challenges that these nanocarriers must overcome to achieve therapeutic efficacy and clinical translation.

Lactoferrin/Hyaluronic acid double-coated lignosulfonate nanoparticles of quinacrine as a controlled release biodegradable nanomedicine targeting pancreatic cancer

Quinacrine is an antimalarial drug that was repositioned for treatment of cancer. This is the first work to enhance quinacrine activity and minimize its associated hepatotoxicity via loading into bio-degradable, bio-renewable lignosulfonate nanoparticles. Particles were appraised for treatment of pancreatic cancer, one of the most life-threatening tumors with a five-year survival estimate. Optimum nanocomposites prepared by polyelectrolyte interaction exhibited a particle size of 138 nm, a negative surface charge (-28 mV) and a pH dependent release of the drug in an acidic environment. Ligands used for active targeting (lactoferrin and hyaluronic acid) were added to nanoparticles' surface via layer by layer coating technique. The highest anticancer activity on PANC-1 cells was demonstrated with dual active targeted particles (3-fold decrease in IC₅₀) along with an increased ability to inhibit migration and invasion of pancreatic cancer cells. In vivo studies revealed that elaborated nanoparticles particles showed the highest tumor volume reduction with enhanced survival without any toxicity on major organs. In conclusion, the elaborated nanoparticles could be considered as a promising targeted nanotherapy for treatment of pancreatic cancer with higher efficacy& survival rate and lower organ toxicity.

Potential of nano-phytochemicals in cervical cancer therapy

Cervical cancer is common among women with a recurrence rate of 35% despite surgery, radiation, and chemotherapy. Patients receiving chemotherapy or radiotherapy routinely experience several side effects including toxicity, non-targeted damage of tissues, hair loss, neurotoxicity, multidrug resistance (MDR), nausea, anemia and neutropenia. Phytochemicals can interfere with almost every stage of carcinogenesis to prevent cancer development. Many natural compounds are known to activate/deactivate multiple redox-sensitive transcription factors that modulate tumor signaling pathways. Polyphenols have been found to be promising agents against cervical cancer. However, applications of phytochemicals as a therapeutic drug are limited due to low oral bioavailability, poor aqueous solubility and requirement of high doses. Nano-sized phytochemicals (NPCs) are promising anti-cancer agents as they are required in minute quantities which lowers overall treatment costs. Several phytochemicals, including quercetin, lycopene, leutin, curcumin, green tea polyphenols and others have been packaged as nanoparticles and proven to be useful in nano-chemoprevention and nano-chemotherapy. Nanoparticles have high biocompatibility, biodegradability and stability in biological environment. Nano-scale drug delivery systems are excellent source for enhanced drug specificity, improved absorption rates, reduced drug degradation and systemic toxicity. The present review discusses current knowledge in the involvement of phytochemical nanoparticles in cervical cancer therapy over conventional chemotherapy.

Development of inhalable quinacrine loaded bovine serum albumin modified cationic nanoparticles: Repurposing quinacrine for lung cancer therapeutics

Drug repurposing is on the rise as an atypical strategy for discovery of new molecules, involving use of pre-existing molecules for a different therapeutic application than the approved indication. Using this strategy, the current study aims to leverage effects of quinacrine (QA), a well-known anti-malarial drug, for treatment of non-small cell lung cancer (NSCLC). For respiratory diseases, designing a QA loaded inhalable delivery system has multiple advantages over invasive delivery. QA-loaded nanoparticles (NPs) were thus prepared using polyethyleneimine (PEI) as a cationic stabilizer. While the use of PEI provided cationic charge on the particles, it also mediated a burst release of QA and demonstrated potential particle toxicity. These concerns were circumvented by coating nanoparticles with bovine serum albumin (BSA), which retained the cationic charge, reduced NP toxicity and modulated QA release. Prepared nanoparticles were characterized for physicochemical properties along with their aerosolization potential. Therapeutic efficacy of the formulations was tested in different NSCLC cells. Mechanism of higher anti-proliferation was evaluated by studying cell cycle profile, apoptosis and molecular markers involved in the progression of lung cancer. BSA coated QA nanoparticles demonstrated good aerosolization potential with a mass median aerodynamic diameter of significantly less than 5 µm. Nanoparticles also demonstrated improved therapeutic efficacy against NSCLC cells in terms of low IC₅₀ values, cell cycle arrest at G2/M phase and autophagy inhibition leading to increased apoptosis. BSA coated QA NPs also demonstrated enhanced therapeutic efficacy in a 3D cell culture model. The present study thus lays solid groundwork for pre-clinical and eventual clinical studies as a standalone therapy and in combination with existing chemotherapeutics.

Quinacrine and curcumin synergistically increased the breast cancer stem cells death by inhibiting ABCG2 and modulating DNA damage repair pathway

Cancer stem cell like cells (CSCs) present a challenge in the management of cancers due to their involvement in the development of resistance against various chemotherapeutic agents. Over expression of ABCG2 transporter gene is one of the factors responsible for drug resistance in CSCs, which causes efflux of therapeutic drugs from these cells. The development of inhibitors against CSCs has not achieved any significant success, till date. In this work, we have evaluated the anti-proliferative activity of curcumin (Cur) and quinacrine (QC) against CSCs using in vitro model system. Cur and QC synergistically inhibited the proliferation, migration and invasion of CSCs enriched side population (SP) cells of cigarette smoke condensate induced breast epithelial transformed (MCF-10A-Tr) generated metastatic cells. Cur + QC combination increased the DNA damage and inhibited the DNA repair pathways in SP cells. Uptake of QC increased in Cur pre-treated SP cells and this combination inhibited the ABCG2 activity by the reduction of ATP hydrolysis in cells. In vitro DNA binding reconstitution system suggests that QC specifically binds to DNA and caused DNA damage inside the cell. Decreased level of ABCG2, representative cell survival and DNA repair proteins were noted after Cur + QC treatment in SP cells. The molecular docking studies were performed to examine the binding behaviour of these drugs with ABCG2, which showed that QC (-53.99 kcal/mol) and Cur (-45.90 kcal/mol) occupy a highly overlapping interaction domain. This suggested that in Cur pre-treated cells, the Cur occupied the ligand-binding site in ABCG2, thus making the ligand binding site unavailable for the QC. This causes an increase in the intracellular concentration of QC. The results indicate that Cur + QC combination causes CSCs death by increasing the concentration of QC in the cells and thus causing the DNA damage and inhibiting the DNA repair pathways through modulating the ABCG2 activity.

Cancer stem cells and nanotechnological approaches for eradication

Cancer stem cells (CSCs) are currently known as the main cause of tumor recurrence. After chemotherapy is completed, CSCs proliferate and then differentiate to generate new tumor tissues. Similar to normal stem cells, this non-uniformly distributed cell population in the tumor tissue has self-renewal capacity and is responsible for survival of the tumor and difference in its genetic and metabolic characteristics. Followed by gene instability in CSCs, new phenotypic markers are aberrantly expressed in CSCs subpopulation. Hence, some of the surface markers and metabolic pathways that are upregulated in CSCs may be applied as specific targets for development of diagnostic and therapeutic approaches. In this review article, the distinctive properties of CSCs including signal pathways implicated in self-renewal and surface markers were discussed. Moreover, targeting CSCs based on their specific properties using nanodrugs was reviewed.

Investigation of Phospholipase Cγ1 Interaction with SLP76 Using Molecular Modeling Methods for Identifying Novel Inhibitors

The enzyme phospholipase C gamma 1 (PLCγ1) has been identified as a potential drug target of interest for various pathological conditions such as immune disorders, systemic lupus erythematosus, and cancers. Targeting its SH3 domain has been recognized as an efficient pharmacological approach for drug discovery against PLCγ1. Therefore, for the first time, a combination of various biophysical methods has been employed to shed light on the atomistic interactions between PLCγ1 and its known binding partners. Indeed, molecular modeling of PLCγ1 with SLP76 peptide and with previously reported inhibitors (ritonavir, anethole, daunorubicin, diflunisal, and rosiglitazone) facilitated the identification of the common critical residues (Gln805, Arg806, Asp808, Glu809, Asp825, Gly827, and Trp828) as well as the quantification of their interaction through binding energies calculations. These features are in agreement with previous experimental data. Such an in depth biophysical analysis of each complex provides an opportunity to identify new inhibitors through pharmacophore mapping, molecular docking and MD simulations. From such a systematic procedure, a total of seven compounds emerged as promising inhibitors, all characterized by a strong binding with PLCγ1 and a comparable or higher binding affinity to ritonavir (∆G_bind < -25 kcal/mol), one of the most potent inhibitor reported till now.

Sonic hedgehog pathway activation regulates cervical cancer stem cell characteristics during epithelial to mesenchymal transition

Resistance to therapy and metastasis remains one of the leading causes of mortality due to cervical cancer despite advances in detection and treatment. The mechanism of epithelial to mesenchymal transition (EMT) provides conceptual explanation to the invasiveness and metastatic spread of cancer but it has not been fully understood in cervical cancer. This study aims to investigate the mechanism by which silencing of E-cadherin gene regulates EMT leading to proliferation, invasion, and chemoresistance of cervical cancer cells through the Hedgehog (Hh) signaling pathway. We developed an in vitro EMT model by the knockdown of E-cadherin expression in cervical cancer cell lines. To understand the role of developmental pathway like Hh in the progression of cervical cancer, we investigated the expression of Hh pathway mediators by array in E-cadherin low cervical cancer cells and observed upregulation of Hh pathway. This was further validated on low passage patient-derived cell lines and cervical carcinoma tissue sections from cervical cancer patients. Further, we evaluated the role of two inhibitors (cyclopamine and GANT58) of the Hh pathway on invasiveness and apoptosis in E-cadherin low cervical cancer cells. In conclusion, we observed that inhibition of Hh pathway with GANT58 along with current therapeutic procedures could be more effective in targeting drug-resistant EMT cells and bulk tumor cells in cervical cancer.

Activation of hedgehog signaling associates with early disease progression in chronic lymphocytic leukemia

Targeted sequencing of 103 leukemia-associated genes in leukemia cells from 841 treatment-naive patients with chronic lymphocytic leukemia (CLL) identified 89 (11%) patients as having CLL cells with mutations in genes encoding proteins that putatively are involved in hedgehog (Hh) signaling. Consistent with this finding, there was a significant association between the presence of these mutations and the expression of GLI1 (χ2 test, P < .0001), reflecting activation of the Hh pathway. However, we discovered that 38% of cases without identified mutations also were GLI1+ Patients with GLI1+ CLL cells had a shorter median treatment-free survival than patients with CLL cells lacking expression of GLI1 independent of IGHV mutation status. We found that GANT61, a small molecule that can inhibit GLI1, was highly cytotoxic for GLI1+ CLL cells relative to that of CLL cells without GLI1. Collectively, this study shows that a large proportion of patients have CLL cells with activated Hh signaling, which is associated with early disease progression and enhanced sensitivity to inhibition of GLI1.

Nanoquinacrine sensitizes 5-FU-resistant cervical cancer stem-like cells by down-regulating Nectin-4 via ADAM-17 mediated NOTCH deregulation

PURPOSE

Cervical cancer is a major cause of cancer-related death in women world-wide. Although the anti-metabolite 5-FU is widely used for its treatment, its clinical utility is limited due to the frequent occurrence of drug resistance during metastasis. Cancer stem-like cells (CSCs), present in the heterogeneous population of CC cells, are thought to contribute to this resistance. Nectin-4, a CSC marker, is known to play an important role in the cellular aggressiveness associated with metastatic CC. This study was designed to assess the role of Nectin-4 in the acquisition of 5-FU resistance by metastatic CC cells, including its relation to the NOTCH signalling pathway.

METHODS

5FU-resistant CC cell lines were deduced from ME-180 and SiHA cells by continuous exposure to a single concentration of 5-FU. Thymidylate synthase (TS) positive cells were isolated from the 5-FU resistant cells, after which a metastatic model was developed. The role of Nectin-4 in the sensitization of 5-FU resistant metastatic CC cells upon incubation with Nano-formulated Quinacrine (NQC) was investigated using multiple bioassays including MTT, FACS, ELISA, immunoflurescence, Western blotting, comet and in vivo plasmid-based short patch and long patch base excision repair assays.

RESULTS

We found that the expression level of Nectin-4, as well as that of other CSC markers (Oct-4, β-catenin, SOX2) and representative NOTCH signalling components (NOTCH-1, Jagged-1, γ-secretase, ADAM-17) were elevated in the 5-FU resistant metastatic cells compared to those in control cells. Increased nuclear translocation of Nectin-4 and increased proliferation and invasion rates were observed after culturing the metastatic cells under hypoxic conditions. Treatment with NQC inhibited the nuclear translocation of Nectin-4 and decreased the proliferation and invasion rates of the cells by inhibiting the induction of base excision repair (BER) pathway components and ADAM-17 expression levels. After combination treatment of Nectin-4 overexpressing metastatic CC cells with a specific ADAM-17 inhibitor (GW280264) and NQC, a decreased Nectin-4 expression, without alterations in BER and/or other NOTCH pathway components, was noted.

CONCLUSION

Our data indicate that Nectin-4 may play a prominent role in 5-FU resistance of metastatic CC cells and that NQC sensitizes these cells by Nectin-4 deregulation through ADAM-17 inhibition, a major component of the NOTCH signalling pathway.

Targeting the Hedgehog Pathway in Cancer: Current Evidence and Future Perspectives

The Hedgehog pathway (HhP) plays an important role in normal embryonic development and its abnormal function has been linked to a variety of neoplasms. Recently, the complex mechanisms involved in this pathway have been deciphered and the cross talks with other important pathways involved in carcinogenesis have been characterized. This knowledge has led to the development of targeted therapies against key components of HhP, which culminated in the approval of vismodegib for the treatment of advanced basal cell carcinoma in 2012. Since then, other compounds have been developed and evaluated in preclinical and clinical studies with interesting results. Today, several medications against components of the HhP have demonstrated clinical activity as monotherapies and in combination with cytotoxic treatment or other targeted therapies against mitogenic pathways that are linked to the HhP. This review aims to clarify the mechanism of the HhP and the complex crosstalk with others pathways involved in carcinogenesis and to discuss both the evidence associated with the growing number of medications and combined therapies addressing this pathway and future perspectives.

Glaucocalyxin A exerts anticancer effect on osteosarcoma by inhibiting GLI1 nuclear translocation via regulating PI3K/Akt pathway

Osteosarcoma, the most common malignant bone tumor with recurring disease or lung metastases, has become one of the leading causes of death in humans. In the current study, we made an investigation on the anticancer effect of glaucocalyxin A, a bioactive ent-kauranoid diterpenoid isolated from Rabdosia japonica var., and unraveled the underlying mechanisms. Here, we found that Glaucocalyxin A inhibited the cell viability of numerous osteosarcoma cells. Our results showed that Glaucocalyxin A exerted the pro-apoptotic effect on human osteosarcoma cells, MG-63 and HOS cells. Glaucocalyxin A induced apoptosis by mitochondrial apoptotic pathway through several steps including increasing the Bax/Bcl-2 ratio, triggering the intracellular reactive oxygen species (ROS) generation, reducing mitochondrial membrane potential (MMP), and inducing cleavage of caspase-9 and caspase-3. We demonstrated that Glaucocalyxin A induced apoptosis via inhibiting Five-zinc finger Glis 1 (GLI1) activation by overexpression and knockdown of GLI1 in vitro. We also found that Glaucocalyxin A inhibited GLI1 activation via regulating phosphatidylinositol 3 kinase/protein kinase B (PI3K/Akt) signaling pathway. We further confirmed our findings by using PI3K activator and inhibitor to verify the inhibitory effect of Glaucocalyxin A on PI3K/Akt/GLI1 pathway. Moreover, our in vivo study revealed that glaucocalyxin A possessed a remarkable antitumor effect with no toxicity in the xenograft model inoculated with HOS tumor through the same mechanisms as in vitro. In conclusion, our results suggested that Glaucocalyxin A induced apoptosis in osteosarcoma by inhibiting nuclear translocation of GLI1 via regulating PI3K/Akt signaling pathway. Thus, Glaucocalyxin A might be a potential candidate for human osteosarcoma in the future.

Targeting GLI Transcription Factors in Cancer

Aberrant activation of hedgehog (Hh) signaling has been observed in a wide variety of tumors and accounts for more than 25% of human cancer deaths. Inhibitors targeting the Hh signal transducer Smoothened (SMO) are widely used and display a good initial efficacy in patients suffering from basal cell carcinoma (BCC); however, a large number of patients relapse. Though SMO mutations may explain acquired therapy resistance, a growing body of evidence suggests that the non-canonical, SMO-independent activation of the Hh pathway in BCC patients can also account for this adverse effect. In this review, we highlight the importance of glioma-associated oncogene (GLI) transcription factors (the main downstream effectors of the canonical and the non-canonical Hh cascade) and their putative role in the regulation of multiple oncogenic signaling pathways. Moreover, we discuss the contribution of the Hh signaling to malignant transformation and propose GLIs as central hubs in tumor signaling networks and thus attractive molecular targets in anti-cancer therapies.

Nanomedicine applications in women's health: state of the art

State-of-the-art applications of nanomedicine have the potential to revolutionize the diagnosis, prevention, and treatment of a range of conditions and diseases affecting women’s health. In this review, we provide a synopsis of potential applications of nanomedicine in some of the most dominant fields of women’s health: mental health, sexual health, reproductive medicine, oncology, menopause-related conditions and dementia. We explore published studies arising from in vitro and in vivo experiments, and clinical trials where available, to reveal novel and highly promising therapeutic applications of nanomedicine in these fields. For the first time, we summarize the growing body of evidence relating to the use of nanomaterials as experimental tools for the detection, prevention, and treatment of significant diseases and conditions across the life course of a cisgender woman, from puberty to menopause; revealing the far-reaching and desirable theoretical impact of nanomedicine across different medical disciplines. We also present an overview of potential concerns regarding the therapeutic applications of nanomedicine and the factors currently restricting the growth of applied nanomedicine.

Quinacrine induces apoptosis in cancer cells by forming a functional bridge between TRAIL-DR5 complex and modulating the mitochondrial intrinsic cascade

Death Receptor 5 (DR5) is known to be an important anti-cancer drug target. TRAIL is a natural ligand of DR5, but its drug action is limited because of several factors. A few agonistic ligands were identified as TRAIL-DR5 axis modulators, which enhance the cellular apoptosis. Literature suggest that quinacrine (QC) acts as a DR5 agonistic ligand. However, the detailed mechanism explaining how QC interacts with TRAIL-DR5 axis has not been established. Also focused in vitro and in vivo experimental analysis to validate the hypothesis is not yet performed. In this work, extensive studies have been carried out using in silico analysis (molecular dynamics), in vitro analysis (cell based assays) and in vivo analysis (based on mice xenograft model), to delineate the mechanism of QC action in modulating the TRAIL-DR5 signaling. The MD simulations helped in identifying the important residues contributing to the formation of a QC-TRAIL-DR5 complex, which provide extra stability to it, consequently leading to the enhanced cellular apoptosis. QC caused a dose dependent increase of DR5 expression in cancer cells but not in normal breast epithelial cells, MCF-10A. QC showed a synergistic effect with TRAIL in causing cancer cell apoptosis. In DR5-KD MCF-10A-Tr (DR5 knocked down) cells, TRAIL+ QC failed to significantly increase the apoptosis but over expression of full length DR5 in DR5-silence cells induced apoptosis, further supporting DR5 as a drug target for QC. An increase in the release of reactive species (ROS and RNS) and activation of enzymes (FADD, CASPASES 3, 8, 9 and cytochrome-C) indicated the involvement of mitochondrial intrinsic pathway in TRAIL+QC mediated apoptosis. In vivo study pointed out that TRAIL+QC co-administration increases the expression of DR5 and reduce the tumor size in xenograft mice. This combined in silico, in vitro and in vivo analysis revealed that QC enhances the cellular apoptosis via the modulation of TRAIL-DR5 complexation and the mitochondrial intrinsic pathway.

Metallic gold and bioactive quinacrine hybrid nanoparticles inhibit oral cancer stem cell and angiogenesis by deregulating inflammatory cytokines in p53 dependent manner

Complete eradication of aggressive oral cancer remains a challenge due to the presence of CSCs. They resist conventional chemotherapeutic agents due to their self-renewal, drug efflux, and efficient DNA repair capacity. Here, we formulated a hybrid-nanoparticle (QAuNP) using quinacrine and gold and characterized/investigated its anti-angiogenic and anti-metastatic effect on OSCC-CSCs. QAuNP significantly inhibited cellular proliferation, caused apoptosis in vitro, and disrupted angiogenesis in vivo and tumor regression in xenograft mice model. It not only inhibited crucial angiogenic markers Ang-1, Ang-2 and VEGF but also depleted MMP-2 in H-357-PEMT cells in a p53 and p21-dependent manner. QAuNP also increased the ROS and NO generation in OSCC-CSCs and reduced the mitochondrial membrane potential. It altered the level of inflammatory cytokines IL-6, IL-1β, TNF-α and metastasis-associated markers (CD-44, CD-133) in H-357-PEMT and CM-treated endothelial cells (HUVEC) in p53/p21-dependent manner. Therefore, QAuNP will be a useful therapeutic agent against metastatic OSCC.

PTTG1 cooperated with GLI1 leads to epithelial-mesenchymal transition in esophageal squamous cell cancer

Pituitary tumor-transforming gene-1 (PTTG1) could acquire its metastasis-promoting effects via inducing epithelial-mesenchymal transition (EMT). However, its role and mechanism in EMT in esophageal squamous cell cancer (ESCC) had not been clearly elucidated. Here, we demonstrated that PTTG1 was overexpressed in ESCC cell lines and tissues especially those with lymph node metastasis. Down regulation of PTTG1 levels dampened the ESCC cells invasion, migration, proliferation ability and colony formation in vitro and inhibited the growth of mouse xenograft model of ESCC cells in vivo. In addition, our in vitro and in vivo experiments consistently showed that decreased PTTG1 led to the inhibition of EMT process. Glioma-associated oncogene homolog1 (GLI1), a key factor in HH-GLI signaling pathway, was also overexpressed in ESCC cells and tissues. Mechanistic studies demonstrated that decreased PTTG1 mitigated the expression levels of GLI1 in vitro and in vivo and ChIP assay also indicated that PTTG1 cooperated with GLI1 by binding to its promoter. Furthermore, overexpression of GLI1 rescued the EMT inhibited by down regulation of PTTG1 in vitro. Together, these data suggested that PTTG1 promoted the invasion ability of ESCC cells via EMT, more important, PTTG1 participated in EMT via activating the expression of GLI1 in ESCC. PTTG1 could be a candidate biomarker for defining ESCC metastasis and useful target for therapy.

SHH gene silencing suppresses epithelial-mesenchymal transition, proliferation, invasion, and migration of cervical cancer cells by repressing the hedgehog signaling pathway

The study aimed to investigate the mechanism by which the sonic Hedgehog (SHH) gene silencing acts upon epithelial-mesenchymal transition (EMT), proliferation, invasion, and migration of cervical cancer (CC) cells via the Hedgehog signaling pathway. RT-qPCR and Western blotting were all employed to detect the SHH mRNA and protein expressions. HeLa and CasKi cells were cultured and subsequently divided into the blank, negative control (NC), and SHH-RNAi groups. A cell counting kit-8 (CCK-8) assay was utilized for cell proliferation. Cell migration and invasion ability were evaluated through scratching test and Transwell assay. The mRNA and protein expressions of the Hedgehog signaling pathway-related factors were detected using RT-qPCR and Western blotting, respectively. After tumor xenograft in nude mice, tumor growth was subsequently observed. SHH mRNA and protein expressions were greater in the SHH-RNAi group than in the blank and NC groups. Compared with the blank group and NC groups, the SHH-RNAi group displayed inhibited levels of proliferation, migration, invasion abilities, as well as a decreased in the Hh signaling pathway-related factors, as well as a reduction in the mRNA and protein expressions of N-cadherin and Vimentin, however, on the contrary increased expressions of E-cadherin were observed. Following tumor xenograft in nude mice, tumor growth was exhibited vast levels of inhibition, particularly in the SHH-RNAi group in comparison to the blank and the NC groups. During the study it was well established that SHH gene silencing suppresses EMT, proliferation, invasion, and migration of CC cells through the repression of the Hedgehog signaling pathway.

Genipin suppresses colorectal cancer cells by inhibiting the Sonic Hedgehog pathway

Genipin, a major component of Gardenia jasminoides Ellis fruit, has been shown to inhibit the growth of gastric, prostate, and breast cancers. However, the anti-proliferative activity of genipin in colorectal cancer (CRC) has not been characterized. Herein, we demonstrated that genipin inhibits the proliferation of CRC cells and that genipin suppressed the Hedgehog pathway. Further investigation showed that p53 and NOXA protein levels were increased during inhibition of Hedgehog pathway-mediated apoptosis in CRC cells. We also showed that p53 modulated the expression of NOXA during genipin-induced apoptosis, and suppression via SMO also played a role in this process. Subsequently, GLI1 was ubiquitinated by the E3 ligase PCAF. In a xenograft tumor model, genipin suppressed tumor growth, which was also associated with Hedgehog inactivation. Taken together, these results suggest that genipin induces apoptosis through the Hedgehog signaling pathway by suppressing p53. These findings reveal a novel regulatory mechanism involving Hedgehog/p53/NOXA signaling in the modulation of CRC cell apoptosis and tumor-forming defects.

Nectin-4 is a breast cancer stem cell marker that induces WNT/β-catenin signaling via Pi3k/Akt axis

Nectin-4 is well known as a junction protein. Recent reports have implicated it in cancer, but there has been little exploration of its functional significance in metastasis and cancer stem cells. Here, using the breast cancer metastasis model system, we report Nectin-4 is a marker for breast cancer stem cells (BCSCs) and provide experimental evidence suggesting that it utilizes WNT/β-Catenin signaling via Pi3k/Akt axis for self renewal of BCSCs. In vitro, in vivo, ex vivo and clinical pathological data showed upregulated Nectin-4 in breast cancer metastasis and WNT/β-Catenin signaling. Nectin-4 depletion inhibited EMT, metastasis, invasion, and the WNT/β-Catenin pathway; conversely, Nectin-4 overexpression in null cells upregulated EMT and metastasis and also induced WNT/β-Catenin signaling via Pi3k/Akt axis, which in turn, controls cancer stem cell proliferation. Induced Nectin-4 was observed in breast tumor patient samples and in breast tumor metastases to axillary lymph nodes, which indicated that Nectin-4 is not only a BCSC marker but also a breast cancer metastasis marker. The current study provides clear evidence that Nectin-4 is a BCSC marker and is responsible for breast cancer metastasis.

Chitosan-Dextran sulfate coated doxorubicin loaded PLGA-PVA-nanoparticles caused apoptosis in doxorubicin resistance breast cancer cells through induction of DNA damage

To overcome the toxicity, pharmacokinetics and drug resistance associated with doxorubicin (DOX), a strategy was developed by encapsulating DOX- loaded-PLGA-PVA- nanoparticles within chitosan-dextran sulfate nanoparticles (CS-DS) [CS-DS-coated-DOX-loaded -PLGA-PVA-NP] and study the sensitivity against DOX- resistance- breast cancer cells (MCF-7-DOX-R). These CS-DS and PLGA-PVA double coated DOX are spherical, stable, polydispersed and have zeta potential +2.89 mV. MCF-7- DOX-R cells were derived by exposing increasing doses of DOX in MCF-7 cells. These cells were resistance to 500 nM of DOX while parental cells were susceptible at 150 nM. The double coated NP caused more cytotoxicity in cancer and MCF-7-DOX-R cells without affecting the normal cells in comparison to DOX-loaded-PLGA-PVA-NP. These NP enhances the uptake of DOX in MCF-7-DOX-R cells and caused apoptosis by increasing apoptotic nuclei, Bax/Bcl-xL ratio, cleaved product PARP-1, tumor suppressor gene p21, p53, topoisomerase inhibition activity, DNA damage and decreasing the migratory potential of cells. An increased S phase arrest was noted in DOX and DOX- loaded- PLGA-PVA-NP treated cells but reduction of S phase and simultaneous increase of Sub-G1 was observed in double coated-NP. Thus, data revealed that CS-DS- DOX- loaded PLGA-PVA- NP caused DOX-resistance cell death by inducing inhibition of topoisomerase activity followed by DNA damage.

A3 Adenosine Receptor Agonist Inhibited Survival of Breast Cancer Stem Cells via GLI-1 and ERK1/2 Pathway

Numerous studies have demonstrated the role of A3 adenosine receptor (A3AR) and signaling pathways in the multiple aspects of the tumor. However, there is a little study about the function of A3AR in the biological processes of cancer stem cells (CSCs). CSCs have a critical role in the maintenance and survival of breast cancer. The aim of current study was to investigate the effect of A3AR agonist on breast cancer stem cells (BCSCs). XTT assay showed antiproliferative effect of A3AR agonist (Cl-IB-MECA) on BCSCs. Our results also demonstrated that A3AR agonist reduces mammosphere formation in a dose-dependent manner. Flow cytometry analysis showed that A3AR agonist induces G1 cell cycle arrest and apoptosis in BCSCs. Western blot assay showed that A3AR agonist inhibits the expression of cell cycle and apoptotic regulatory proteins as well as the expression of ERK1/2 and GLI-1 proteins. Finally, these findings propose that A3AR agonist induces cell cycle arrest and apoptosis in BCSCs by inhibition of ERK1/2 and GLI-1 cascade. J. Cell. Biochem. 118: 2909-2920, 2017. © 2017 Wiley Periodicals, Inc.

Scaffold-Hopping of Aurones: 2-Arylideneimidazo[1,2-a]pyridinones as Topoisomerase IIα-Inhibiting Anticancer Agents

Scaffold-hopping of bioactive natural product aurones has been studied for the first time. 2-Arylideneimidazo[1,2-a]pyridinones as potential topoisomerase IIα (hTopoIIα)-targeting anticancer compounds were considered. A multifunctional activator, polyphosphoric acid, enabled to realize a cascade reaction of 2-aminopyridine with 2,3-epoxyesters toward synthesis of 2-arylideneimidazo[1,2-a]pyridinones. Most of the compounds exhibited hTopoIIα-selective poison activity with efficiency more than etoposide and DNA-binding property, while not interacting with hTopo I. The compounds showed pronounced antiproliferative activities in nanomolar range with relatively poor toxicity to normal cells, inhibition of invasiveness, and apoptotic effect. The activities for inhibition of tubulin assembly, CDK1 and pCDK1, were also observed. Interestingly, the hTopoIIα inhibitory (in vitro and ex vivo studies) and antiproliferative activities of representative potent compounds were found to be manifold higher compared to corresponding parent aurones bearing alike substitutions, indicating the importance of such scaffold-hopping strategy in medicinal chemistry research.

Crosstalk between SHH and stemness state signaling pathways in esophageal squamous cell carcinoma

The expression of GLI1 as a downstream gene of sonic hedgehog (Hh) pathway, studied in a variety of cancers including esophageal squamous cell carcinoma (ESCC). However, the interaction of Hh with other developmental pathways needs to be elucidated. In this study, we aimed to investigate the correlation of GLI1 expression with transcription factors (TFs) of stem cell signaling pathways, and their association with clinico-pathological data of ESCC. Using real-time PCR, we assessed the expression of GLI1 mRNA in 49 ESCC patients, and analyzed the correlation between GLI1 and selected TFs. The results showed overexpression of GLI1 in ESCC tissues in significant correlation with lymph node metastasis. The GLI1 up-regulation was also correlated to the SOX2 and SIZN1 (Smad-interacting zinc finger protein) expression. These correlations may confirmed the role of GLI1 in crosstalk among different cell signaling pathways in ESCC. To our knowledge, this is the first study to demonstrate the correlation of GLI1 expression with stemness marker and BMP signaling in ESCC.