Inhibition of NF-kappaB signaling by quinacrine is cytotoxic to human colon carcinoma cell lines and is synergistic in combination with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) or oxaliplatin

AI identifies potent inducers of breast cancer stem cell differentiation based on adversarial learning from gene expression data

Cancer stem cells (CSCs) are a subpopulation of cancer cells within tumors that exhibit stem-like properties and represent a potentially effective therapeutic target toward long-term remission by means of differentiation induction. By leveraging an artificial intelligence approach solely based on transcriptomics data, this study scored a large library of small molecules based on their predicted ability to induce differentiation in stem-like cells. In particular, a deep neural network model was trained using publicly available single-cell RNA-Seq data obtained from untreated human-induced pluripotent stem cells at various differentiation stages and subsequently utilized to screen drug-induced gene expression profiles from the Library of Integrated Network-based Cellular Signatures (LINCS) database. The challenge of adapting such different data domains was tackled by devising an adversarial learning approach that was able to effectively identify and remove domain-specific bias during the training phase. Experimental validation in MDA-MB-231 and MCF7 cells demonstrated the efficacy of five out of six tested molecules among those scored highest by the model. In particular, the efficacy of triptolide, OTS-167, quinacrine, granisetron and A-443654 offer a potential avenue for targeted therapies against breast CSCs.

Quinacrine enhances the efficacy of cisplatin by increasing apoptosis and modulating cancer survival proteins in a colorectal cancer cell line

BACKGROUND

Cisplatin and platinum-based compounds have been used successfully to treat various cancers. However, their use is often restricted due to the acquired resistance by cancer cells. Over-expression of p53 and inhibition of NF-kB sensitize several cancer cells towards cisplatin-induced apoptosis. Quinacrine, a cytotoxic drug with predictable safety revealed to concurrently suppress NF-kB and activate p53, which may be an attractive adjuvant in cisplatin chemotherapy. Therefore, the objective of the present study was to establish the role of quinacrine as an adjuvant in lowering the dose of cisplatin during cancer therapy to circumvent its toxic effects.

MATERIALS AND METHODS

The colon cancer (HCT-8) cells were cultured and cell survival assays were performed using standard procedures. Cell cycle arrest and the extent of apoptosis were determined using a muse cell analyzer. Cancer survival proteins were analyzed using western blotting techniques.

RESULTS AND CONCLUSION

We demonstrated that concomitant use of quinacrine with cisplatin increased cell apoptosis, suppressed cell proliferation and inhibited colony formation in a colorectal cancer cell line. Moreover, cell cycle arrest in the G0/G1 and G2/M phases and upregulation of p53 expression were observed. There was also downregulation of NF-kB and Bcl-xL protein expressions, both of which are associated with enhanced cell apoptosis and an increase in the sensitivity of cancer cells to cisplatin, overcoming its chemoresistance. Overall, the results of the present study and available literature clearly indicate that the use of quinacrine as an adjuvant with cisplatin may enhance its anti-cancer activity and reduce chemoresistance.

Critical signaling pathways governing colitis-associated colorectal cancer: Signaling, therapeutic implications, and challenges

Long-term colitis in people with inflammatory bowel disease (IBD) may lead to colon cancer called colitis-associated colorectal cancer (CAC). Since the advent of preclinical prototypes of CAC, various immunological messaging cascades have been identified as implicated in developing this disease. The toll-like receptor (TLR)s, Janus kinase (JAK)-signal transducer and activator of transcription (STAT), Nuclear factor-kappa B (NF-κB), mammalian target of rapamycin complex (mTOR), autophagy, and oxidative stress are only a few of the molecular mechanisms that have been recognized as major components to CAC progression. These pathways may also represent attractive medicinal candidates for the prevention and management of CAC. CAC signaling mechanisms at the molecular level and how their dysregulation may cause illness are summarized in this comprehensive overview.

Zooming in on common immune evasion mechanisms of pathogens in phagolysosomes: potential broad-spectrum therapeutic targets against infectious diseases

The intracellular viral, bacterial, or parasitic pathogens evade the host immune challenges to propagate and cause fatal diseases. The microbes overpower host immunity at various levels including during entry into host cells, phagosome formation, phagosome maturation, phagosome-lysosome fusion forming phagolysosomes, acidification of phagolysosomes, and at times after escape into the cytosol. Phagolysosome is the final organelle in the phagocyte with sophisticated mechanisms to degrade the pathogens. The immune evasion strategies by the pathogens include the arrest of host cell apoptosis, decrease in reactive oxygen species, the elevation of Th2 anti-inflammatory response, avoidance of autophagy and antigen cross-presentation pathways, and escape from phagolysosomal killing. Since the phagolysosome organelle in relation to infection/cure is seldom discussed in the literature, we summarize here the common host as well as pathogen targets manipulated or utilized by the pathogens established in phagosomes and phagolysosomes, to hijack the host immune system for their benefit. These common molecules or pathways can be broad-spectrum therapeutic targets for drug development for intervention against infectious diseases caused by different intracellular pathogens.

In Vitro Anticancer Activity of Methanolic Extract of Justicia adhatoda Leaves with Special Emphasis on Human Breast Cancer Cell Line

Natural products are being targeted as alternative anticancer agents due to their non-toxic and safe nature. The present study was conducted to explore the in vitro anticancer potential of Justicia adhatoda (J. adhatoda) leaf extract. The methanolic leaf extract was prepared, and the phytochemicals and antioxidant potential were determined by LCMS analysis and DPPH radical scavenging assay, respectively. A docking study performed with five major alkaloidal phytoconstituents showed that they had a good binding affinity towards the active site of NF-κB. Cell viability assay was carried out in five different cell lines, and the extract exhibited the highest cytotoxicity in MCF-7, a breast cancer cell line. Extract-treated cells showed a significant increase in nitric oxide and reactive oxygen species production. Cell cycle analysis showed an arrest in cell growth at the Sub-G0 phase. The extract successfully inhibited cell migration and colony formation and altered mitochondrial membrane potential. The activities of superoxide dismutase and glutathione were also found to decrease in a dose-dependent manner. The percentage of apoptotic cells was found to increase in a dose-dependent manner in MCF-7 cells. The expressions of caspase-3, Bax, and cleaved-PARP were increased in extract-treated cells. An increase in the expression of NF-κB was found in the cytoplasm in extract-treated cells. J. adhatoda leaf extract showed a potential anticancer effect in MCF-7 cells.

Microsatellite Status and IκBα Expression Levels Predict Sensitivity to Pharmaceutical Curcumin in Colorectal Cancer Cells

Simple Summary

The global burden of colorectal cancer is high. Chemotherapy has been the backbone of colorectal cancer therapy for decades. Toxic side effects and frequently occurring drug resistances remain challenging problems. Therefore, exploring natural compounds with low or even no toxicity holds great potential. However, natural curcumin is poorly absorbed, limiting its clinical use. Therefore, our focus was to screen different molecular types of colorectal cancer to find the ones with the highest sensitivity to curcumin. We observed very individual responses to curcumin for various colorectal cancer cell lines. Most curcumin-sensitive cell lines were of the microsatellite-stable molecular type, and expressed high baseline levels of the IκBα protein. Contrarily, curcumin-resistant lines were mainly microsatellite instable, with low baseline IκBα levels. Considering all of the data obtained, we conclude that patients with microsatellite-stable tumors and high baseline IκBα protein expression would benefit from treatment with novel curcumin formulations and derivatives.

Abstract

Clinical utilization of curcumin in colorectal cancer (CRC) was revived as a result of the development of novel curcumin formulations with improved bioavailability. Additionally, identification of biomarkers for curcumin sensitivity would also promote successful clinical applications. Here, we wanted to identify such biomarkers in order to establish a predictive model for curcumin sensitivity. Thirty-two low-passage CRC cell lines with specified tumor characteristics were included. Curcumin suppressed cell proliferation, yet sensitivity levels were distinct. Most curcumin-sensitive CRC cell lines were microsatellite stable and expressed high levels of IκBα. The predictive capacity of this biomarker combination possessed a statistical significance of 72% probability to distinguish correctly between curcumin-sensitive and -resistant CRC cell lines. Detailed functional analyses were performed with three sensitive and three resistant CRC cell lines. As curcumin’s mode of action, inhibition of NF-κB p65 activation via IκBα was identified. In consequence, we hypothesize that novel curcumin formulations—either alone or, more likely, in combination with standard therapeutics—can be expected to prove clinically beneficial for CRC patients with high IκBα expression levels.

Effects of Lactobacillus acidophilus KLDS1.0901 on Proliferation and Apoptosis of Colon Cancer Cells

Colon cancer is the most common type of malignant tumor. The cytotoxicity effect of lactic acid bacteria may be active by inhibiting cancer cell proliferation, producing anticancer compounds, and inducing apoptosis in cancer cells, but the mechanism is unclear. Our previous study revealed that Lactobacillus acidophilus KLDS1.0901 has good probiotic properties. In this study, We screened out the highest inhibition rate of L. acidophilus KLDS1.0901 and assessed the effects on the proliferation of HT-29, Caco-2, and IEC-6 cells. Then, the apoptosis mechanism of HT-29 cells was studied when treated with L. acidophilus KLDS1.0901. Results showed that L. acidophilus KLDS1.0901 inhibited the proliferation of HT-29 and Caco-2 cells in a dose-dependent manner and reached the maximum under the condition of multiplicity of infection (MOI) = 100 (rate of Lactobacillus to cells) at 48 h. With the increase in time and MOI, reactive oxygen species in HT-29 cells, the apoptosis rates of HT-29 cells were increased, and the amount of blue fluorescence of the cells was also increased after Hoechst 33258 staining. Furthermore, L. acidophilus KLDS1.0901 reduced the mitochondrial membrane potential of HT-29 cells. Notably, 1,133 differentially expressed genes were screened by transcriptomics research, including 531 up-regulated genes and 602 down-regulated genes. These genes were involved in the nuclear factor κB and PI3K-AKT signaling pathways related to the apoptosis of HT-29 cells. These findings suggested that L. acidophilus KLDS1.0901 has the potential to be used in the development of a new type of functional foods for adjuvant treatment of colon cancer.

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.

Quinacrine-CASIN combination overcomes chemoresistance in human acute lymphoid leukemia

Chemoresistance posts a major hurdle for treatment of acute leukemia. There is increasing evidence that prolonged and intensive chemotherapy often fails to eradicate leukemic stem cells, which are protected by the bone marrow niche and can induce relapse. Thus, new therapeutic approaches to overcome chemoresistance are urgently needed. By conducting an ex vivo small molecule screen, here we have identified Quinacrine (QC) as a sensitizer for Cytarabine (AraC) in treating acute lymphoblastic leukemia (ALL). We show that QC enhances AraC-mediated killing of ALL cells, and subsequently abrogates AraC resistance both in vitro and in an ALL-xenograft model. However, while combo AraC+QC treatment prolongs the survival of primary transplanted recipients, the combination exhibits limited efficacy in secondary transplanted recipients, consistent with the survival of niche-protected leukemia stem cells. Introduction of Cdc42 Activity Specific Inhibitor, CASIN, enhances the eradication of ALL leukemia stem cells by AraC+QC and prolongs the survival of both primary and secondary transplanted recipients without affecting normal long-term human hematopoiesis. Together, our findings identify a small-molecule regimen that sensitizes AraC-mediated leukemia eradication and provide a potential therapeutic approach for better ALL treatment.

Acridine-O6-benzylguanine hybrids: Synthesis, DNA binding, MGMT inhibition and antiproliferative activity

O⁶-Methylguanine-DNA-methyltransferase (MGMT) is a key DNA repair enzyme involved in chemoresistance to DNA-alkylating anti-cancer drugs such as Temozolomide (TMZ) through direct repair of drug-induced O⁶-methylguanine residues in DNA. MGMT substrate analogues, such as O⁶-benzylguanine (BG), efficiently inactivate MGMT in vitro and in cells; however, these drugs failed to reach the clinic due to adverse side effects. Here, we designed hybrid drugs combining a BG residue covalently linked to a DNA-interacting moiety (6-chloro-2-methoxy-9-aminoacridine). Specifically, two series of hybrids, encompassing three compounds each, were obtained by varying the position of the attachment point of BG (N⁹ of guanine vs. the benzyl group) and the length and nature of the linker. UV/vis absorption and fluorescence data indicate that all six hybrids adopt an intramolecularly stacked conformation in aqueous solutions in a wide range of temperatures. All hybrids interact with double-stranded DNA, as clearly evidenced by spectrophotometric titrations, without intercalation of the acridine ring and do not induce thermal stabilization of the duplex. All hybrids, as well as the reference DNA intercalator (6-chloro-2-methoxy-9-aminoacridine 8), irreversibly inhibit MGMT in vitro with variable efficiency, comparable to that of BG. In a multidrug-resistant glioblastoma cell line T98G, benzyl-linked hybrids 7a-c and the N⁹-linked hybrid 19b are moderately cytotoxic (GI₅₀ ≥ 15 μM after 96 h), while N⁹-linked hybrids 19a and 19c are strongly cytotoxic (GI₅₀ = 1-2 μM), similarly to acridine 8 (GI₅₀ = 0.6 μM). Among all compounds, hybrids 19a and 19c, similarly to BG, display synergic cytotoxic effect upon co-treatment with subtoxic doses of TMZ, with combination index (CI) values as low as 0.2-0.3. In agreement with in vitro results, compound 19a inactivates cellular MGMT but, unlike BG, does not induce significant levels of DNA damage, either alone or in combination with TMZ, as indicated by the results of γH2AX immunostaining experiments. Instead, and unlike BG, compound 19a alone induces significant apoptosis of T98G cells, which is not further increased in a combination with TMZ. These results indicate that molecular mechanisms underlying the cytotoxicity of 19a and its combination with TMZ are distinct from that of BG. The strongly synergic properties of this combination represent an interesting therapeutic opportunity in treating TMZ-resistant cancers.

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.

Atypical protein kinase C is essential for embryonic vascular development in mice

The atypical PKC (aPKC) subfamily constitutes PKCζ and PKCλ in mice, and both aPKC isoforms have been proposed to be involved in regulating various endothelial cell (EC) functions. However, the physiological function of aPKC in ECs during embryonic development has not been well understood. To address this question, we utilized Tie2-Cre to delete PKCλ alone (PKCλ-SKO) or both PKCλ and PKCζ (DKO) in ECs, and found that all DKO mice died at around the embryonic day 11.5 (E11.5), whereas a small proportion of PKCλ-SKO mice survived till birth. PKCλ-SKO embryos also exhibited less phenotypic severity than DKO embryos at E10.5 and E11.5, suggesting a potential compensatory role of PKCζ for PKCλ in embryonic ECs. We then focused on DKO embryos and investigated the effects of aPKC deficiency on embryonic vascular development. At E9.5, deletion of both aPKC isoforms reduced the diameters of vitelline artery and vein, and decreased branching from both vitelline vessels in yolk sac. Ablation of both aPKC isoforms also disrupted embryonic angiogenesis in head and trunk at the same stage, increasing apoptosis of both ECs and non-ECs. Taken together, our results demonstrated that aPKC in ECs plays an essential role in regulating cell apoptosis, angiogenesis, and embryonic survival.

Targeting tumor hypoxia and mitochondrial metabolism with anti-parasitic drugs to improve radiation response in high-grade gliomas

High-grade gliomas (HGGs), including glioblastoma and diffuse intrinsic pontine glioma, are amongst the most fatal brain tumors. These tumors are associated with a dismal prognosis with a median survival of less than 15 months. Radiotherapy has been the mainstay of treatment of HGGs for decades; however, pronounced radioresistance is the major obstacle towards the successful radiotherapy treatment. Herein, tumor hypoxia is identified as a significant contributor to the radioresistance of HGGs as oxygenation is critical for the effectiveness of radiotherapy. Hypoxia plays a fundamental role in the aggressive and resistant phenotype of all solid tumors, including HGGs, by upregulating hypoxia-inducible factors (HIFs) which stimulate vital enzymes responsible for cancer survival under hypoxic stress. Since current attempts to target tumor hypoxia focus on reducing oxygen demand of tumor cells by decreasing oxygen consumption rate (OCR), an attractive strategy to achieve this is by inhibiting mitochondrial oxidative phosphorylation, as it could decrease OCR, and increase oxygenation, and could therefore improve the radiation response in HGGs. This approach would also help in eradicating the radioresistant glioma stem cells (GSCs) as these predominantly rely on mitochondrial metabolism for survival. Here, we highlight the potential for repurposing anti-parasitic drugs to abolish tumor hypoxia and induce apoptosis of GSCs. Current literature provides compelling evidence that these drugs (atovaquone, ivermectin, proguanil, mefloquine, and quinacrine) could be effective against cancers by mechanisms including inhibition of mitochondrial metabolism and tumor hypoxia and inducing DNA damage. Therefore, combining these drugs with radiotherapy could potentially enhance the radiosensitivity of HGGs. The reported efficacy of these agents against glioblastomas and their ability to penetrate the blood-brain barrier provides further support towards promising results and clinical translation of these agents for HGGs treatment.

Colorectal cancer residual disease at maximal response to EGFR blockade displays a druggable Paneth cell-like phenotype

Blockade of epidermal growth factor receptor (EGFR) causes tumor regression in some patients with metastatic colorectal cancer (mCRC). However, residual disease reservoirs typically remain even after maximal response to therapy, leading to relapse. Using patient-derived xenografts (PDXs), we observed that mCRC cells surviving EGFR inhibition exhibited gene expression patterns similar to those of a quiescent subpopulation of normal intestinal secretory precursors with Paneth cell characteristics. Compared with untreated tumors, these pseudodifferentiated tumor remnants had reduced expression of genes encoding EGFR-activating ligands, enhanced activity of human epidermal growth factor receptor 2 (HER2) and HER3, and persistent signaling along the phosphatidylinositol 3-kinase (PI3K) pathway. Clinically, properties of residual disease cells from the PDX models were detected in lingering tumors of responsive patients and in tumors of individuals who had experienced early recurrence. Mechanistically, residual tumor reprogramming after EGFR neutralization was mediated by inactivation of Yes-associated protein (YAP), a master regulator of intestinal epithelium recovery from injury. In preclinical trials, Pan-HER antibodies minimized residual disease, blunted PI3K signaling, and induced long-term tumor control after treatment discontinuation. We found that tolerance to EGFR inhibition is characterized by inactivation of an intrinsic lineage program that drives both regenerative signaling during intestinal repair and EGFR-dependent tumorigenesis. Thus, our results shed light on CRC lineage plasticity as an adaptive escape mechanism from EGFR-targeted therapy and suggest opportunities to preemptively target residual disease.

Targeting NF-κB Signaling by Calebin A, a Compound of Turmeric, in Multicellular Tumor Microenvironment: Potential Role of Apoptosis Induction in CRC Cells

Increasing lines of evidence suggest that chronic inflammation mediates most chronic diseases, including cancer. The transcription factor, NF-κB, has been shown to be a major regulator of inflammation and metastasis in tumor cells. Therefore, compounds or any natural agents that can inhibit NF-κB activation have the potential to prevent and treat cancer. However, the mechanism by which Calebin A, a component of turmeric, regulates inflammation and disrupts the interaction between HCT116 colorectal cancer (CRC) cells and multicellular tumor microenvironment (TME) is still poorly understood. The 3D-alginate HCT116 cell cultures in TME were treated with Calebin A, BMS-345541, and dithiothreitol (DTT) and examined for invasiveness, proliferation, and apoptosis. The mechanism of TME-induced malignancy of cancer cells was confirmed by phase contrast, Western blotting, immunofluorescence, and DNA-binding assay. We found through DNA binding assay, that Calebin A inhibited TME-induced NF-κB activation in a dose-dependent manner. As a result of this inhibition, NF-κB phosphorylation and NF-κB nuclear translocation were down-modulated. Calebin A, or IκB-kinase (IKK) inhibitor (BMS-345541) significantly inhibited the direct interaction of nuclear p65 to DNA, and interestingly this interaction was reversed by DTT. Calebin A also suppressed the expression of NF-κB-promoted anti-apoptotic (Bcl-2, Bcl-xL, survivin), proliferation (Cyclin D1), invasion (MMP-9), metastasis (CXCR4), and down-regulated apoptosis (Caspase-3) gene biomarkers, leading to apoptosis in HCT116 cells. These results suggest that Calebin A can suppress multicellular TME-promoted CRC cell invasion and malignancy by inhibiting the NF-κB-promoting inflammatory pathway associated with carcinogenesis, underlining the potential of Calebin A for CRC treatment.

Regorafenib suppresses epidermal growth factor receptor signaling-modulated progression of colorectal cancer

Active epidermal growth factor receptors (EGFR) signaling mediates the progression of colorectal cancer (CRC) through activation of downstream kinases and transcription factors. The increased expression of EGFR was associated with worse prognosis in patients with metastatic CRC (mCRC). Regorafenib, the oral kinase inhibitor approved for the treatment of mCRC, has been shown to reduce activation of downstream kinases of EGFR signal pathway in hepatocellular carcinoma and osteosarcoma. However, whether EGFR inactivation was participates in regorafenib-inhibited progression of CRC still remaining ambiguous. The major purpose of present study was to verify effect of regorafenib on EGFR signaling-mediated progression of CRC. Here, we investigated the effect of regorafenib or erlotinib (EGFR inhibitor) on tumor cell growth, invasion ability, apoptotic, and EGFR signal transduction in CRC in vitro and in vivo. Our results indicated regorafenib reduced EGF-induced EGFR and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activity. Both regorafenib and erlotinib significantly reduced cell invasion ability, activation of protein kinase C-δ (PKCδ), protein kinase B (AKT), extracellular signal-regulated kinases (ERK), and NF-κB. Regorafenib can trigger the inhibition of tumor cell growth and the induction of apoptosis through extrinsic/intrinsic apoptosis pathways. In addition, the expression of NF-κB-mediated proteins involved in tumor progression was also suppressed by regorafenib treatment. Taken together, regorafenib acts as a inhibitor of EGFR signaling that attenuated the activation of EGFR and EGFR related downstream signaling cascades in CRC. Our results suggested that the suppression of EGFR signaling was associated with regorafenib-inhibited progression of CRC.

Targeting apoptotic caspases in cancer

Members of the caspase family of proteases play essential roles in the initiation and execution of apoptosis. These caspases are divided into two groups: the initiator caspases (caspase-2, -8, -9 and -10), which are the first to be activated in response to a signal, and the executioner caspases (caspase-3, -6, and -7) that carry out the demolition phase of apoptosis. Many conventional cancer therapies induce apoptosis to remove the cancer cell by engaging these caspases indirectly. Newer therapeutic applications have been designed, including those that specifically activate individual caspases using gene therapy approaches and small molecules that repress natural inhibitors of caspases already present in the cell. For such approaches to have maximal clinical efficacy, emerging insights into non-apoptotic roles of these caspases need to be considered. This review will discuss the roles of caspases as safeguards against cancer in the context of the advantages and potential limitations of targeting apoptotic caspases for the treatment of cancer.

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.

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.

Role of the NF-κB signaling pathway in the pathogenesis of colorectal cancer

The NF-κB signaling pathway is a key regulator of CRC cell proliferation, apoptosis, angiogenesis, inflammation, metastasis, and drug resistance. Over-activation of the NF-κB pathway is a feature of colorectal cancer (CRC). While new combinatorial treatments have improved overall patient outcome; quality of life, cost of care, and patient survival rate have seen little improvement. Suppression of the NF-κB signaling pathway using biological or specific pharmacological inhibitors is a potential therapeutic approach in the treatment of colon cancer. This review summarizes the regulatory role of NF-κB signaling pathway in the pathogenesis of CRC for a better understanding and hence a better management of the disease.

Expression of DR5 and c‑FLIP proteins as novel prognostic biomarkers for non‑small cell lung cancer patients treated with surgical resection and chemotherapy

TRAIL-R2 (DR5), one of the death receptors, can activate the extrinsic apoptosis pathway, while cellular FLICE-inhibitory protein (c-FLIP) can inhibit this pathway. Both of them play important roles in the occurrence and development of most tumors. To date, there is no relevant report concerning the relationship between expression of DR5 and c-FLIP protein and clinicopathological/prognostic implications in patients with non-small cell lung cancer (NSCLC) treated with surgical resection and chemotherapy. Thus, the aim of the present study was to investigate the potential prognostic significance of DR5 and c-FLIP in NSCLC patients and their predictive roles in the chemotherapeutic response. In the present study, DR5 and c-FLIP were detected by immunohistochemistry (IHC) in tissue microarrays of NSCLC. The results showed that the expression levels of DR5 and c-FLIP were significantly higher in lung squamous cell carcinoma (SCC) and lung adenocarcinoma (ADC) tissues compared with levels noted in the non-cancerous control lung tissues (all P<0.05). In addition, DR5 expression was significantly increased in lung ADC (P<0.001), whereas, c-FLIP was higher in lung SCC (P<0.001) and smoker patients with clinical stage III (P=0.019, P=0.016, respectively). In addition, NSCLC patients with overexpression of DR5 and loss of c-FLIP expression exhibited a higher overall survival (OS) rate as determined by Kaplan-Meier analysis (P=0.029, P=0.038, respectively). Multivariate analysis confirmed that high expression of DR5 and loss of c-FLIP expression were independent favorable prognostic factors for NSCLC patients (P=0.016, P=0.035, respectively). In conclusion, overexpression of DR5 and loss of c-FLIP expression may serve as novel favorable prognostic biomarkers for NSCLC patients treated with chemotherapy after radical resection and used as predictors for tumor response to chemotherapy drugs.

Repurposing quinacrine for treatment-refractory cancer

Quinacrine, also known as mepacrine, has originally been used as an antimalarial drug for close to a century, but was recently rediscovered as an anticancer agent. The mechanisms of anticancer effects of quinacrine are not well understood. The anticancer potential of quinacrine was discovered in a screen for small molecule activators of p53, and was specifically shown to inhibit NFκB suppression of p53. However, quinacrine can cause cell death in cells that lack p53 or have p53 mutations, which is a common occurrence in many malignant tumors including high grade serous ovarian cancer. Recent reports suggest quinacrine may inhibit cancer cell growth through multiple mechanisms including regulating autophagy, FACT (facilitates chromatin transcription) chromatin trapping, and the DNA repair process. Additional reports also suggest quinacrine is effective against chemoresistant gynecologic cancer. In this review, we discuss anticancer effects of quinacrine and potential mechanisms of action with a specific focus on gynecologic and breast cancer where treatment-refractory tumors are associated with increased mortality rates. Repurposing quinacrine as an anticancer agent appears to be a promising strategy based on its ability to target multiple pathways, its selectivity against cancer cells, and the synergistic cytotoxicity when combined with other anticancer agents with limited side effects and good tolerability profile.

Proteomic Analysis of miR-195 and miR-497 Replacement Reveals Potential Candidates that Increase Sensitivity to Oxaliplatin in MSI/P53wt Colorectal Cancer Cells

Most patients with advanced colorectal cancer (CRC) eventually develop resistance to systemic combination therapy. miR-195-5p and miR-497-5p are downregulated in CRC tissues and associated with drug resistance. Sensitization to 5-FU, oxaliplatin, and irinotecan by transfection with miR-195-5p and miR-497-5p mimics was studied using cell viability and clonogenic assays in cell lines HCT116, RKO, DLD-1, and SW480. In addition, proteomic analysis of transfected cells was implemented to identify potential targets. Significantly altered proteins were subjected to STRING (protein-protein interaction networks) database analysis to study the potential mechanisms of drug resistance. Cell viability analysis of transfected cells revealed increased sensitivity to oxaliplatin in microsatellite instable (MSI)/P53 wild-type HCT116 and RKO cells. HCT116 transfected cells formed significantly fewer colonies when treated with oxaliplatin. In sensitized cells, proteomic analysis showed 158 and 202 proteins with significantly altered expression after transfection with miR-195-5p and miR-497-5p mimics respectively, of which CHUK and LUZP1 proved to be coinciding downregulated proteins. Resistance mechanisms of these proteins may be associated with nuclear factor kappa-B signaling and G1 cell-cycle arrest. In conclusion, miR-195-5p and miR-497-5p replacement enhanced sensitivity to oxaliplatin in treatment naïve MSI/P53 wild-type CRC cells. Proteomic analysis revealed potential miRNA targets associated with the cell-cycle which possibly bare a relation with chemotherapy sensitivity.

Novel applications for an established antimalarial drug: tumoricidal activity of quinacrine

Quinacrine (QC), a synthetic antimalarial drug, was consistently used worldwide to combat malaria during the last century. Interestingly, later studies revealed that it also displays various additional properties, specifically antitumor activity. QC's antitumor activity occurs via a variety of pathways, including DNA intercalation, angiogenesis inhibition, signal transduction regulation, cell cycle arrest and autophagy induction. In combination with traditional therapies such as chemotherapy and radiotherapy, QC has also displayed synergistic effects against tumors, which may open promising therapeutic avenues. However, the breadth and complexity of its antitumor mechanisms have not yet been fully elucidated. In this review, we have systematically categorized QC's reported antitumor mechanisms from recent studies, to enable a deeper understanding of its antitumor activity.

Angiotensin II increases angiogenesis by NF-κB-mediated transcriptional activation of angiogenic factor AGGF1

Angiogenic factor with G-patch and FHA domains 1 (AGGF1) is involved in vascular development, angiogenesis, specification of hemangioblasts, and differentiation of veins. When mutated, however, it causes Klippel-Trenaunay syndrome, a vascular disorder. In this study, we show that angiotensin II (AngII)-the major effector of the renin-angiotensin system and one of the most important regulators of the cardiovascular system-induces the expression of AGGF1 through NF-κB, and that AGGF1 plays a key role in AngII-induced angiogenesis. AngII significantly up-regulated the levels of AGGF1 mRNA and protein in HUVECs at concentrations of 10-40 μg/ml but not >60 μg/ml. AngII type 1 receptor (AT1R) inhibitor losartan inhibited AngII-induced up-regulation of AGGF1, whereas AT2R inhibitor PD123319 further increased AngII-induced up-regulation of AGGF1. Up-regulation of AGGF1 by AngII was blocked by NF-κB inhibitors, and p65 binds directly to a binding site at the promoter/regulatory region of AGGF1 and transcriptionally activates AGGF1 expression. AngII-induced endothelial tube formation was blocked by small interfering RNAs (siRNAs) for RELA (RELA proto-oncogene, NF-κB subunit)/p65 or AGGF1, and the effect of RELA siRNA was rescued by AGGF1. AngII-induced angiogenesis from aortic rings was severely impaired in Aggf1^+/- mice, and the effect was restored by AGGF1. These data suggest that AngII acts as a critical regulator of AGGF1 expression through NF-κB, and that AGGF1 plays a key role in AngII-induced angiogenesis.-Si, W., Xie, W., Deng, W., Xiao, Y., Karnik, S. S., Xu, C., Chen, Q., Wang, Q. K. Angiotensin II increases angiogenesis by NF-κB-mediated transcriptional activation of angiogenic factor AGGF1.

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.

Acid ceramidase is upregulated in AML and represents a novel therapeutic target

There is an urgent unmet need for new therapeutics in acute myeloid leukemia (AML) as standard therapy has not changed in the past three decades and outcome remains poor for most patients. Sphingolipid dysregulation through decreased ceramide levels and elevated sphingosine 1-phosphate (S1P) promotes cancer cell growth and survival. Acid ceramidase (AC) catalyzes ceramide breakdown to sphingosine, the precursor for S1P. We report for the first time that AC is required for AML blast survival. Transcriptome analysis and enzymatic assay show that primary AML cells have high levels of AC expression and activity. Treatment of patient samples and cell lines with AC inhibitor LCL204 reduced viability and induced apoptosis. AC overexpression increased the expression of anti-apoptotic Mcl-1, significantly increased S1P and decreased ceramide. Conversely, LCL204 induced ceramide accumulation and decreased Mcl-1 through post-translational mechanisms. LCL204 treatment significantly increased overall survival of C57BL/6 mice engrafted with leukemic C1498 cells and significantly decreased leukemic burden in NSG mice engrafted with primary human AML cells. Collectively, these studies demonstrate that AC plays a critical role in AML survival through regulation of both sphingolipid levels and Mcl-1. We propose that AC warrants further exploration as a novel therapeutic target in AML.

A Combination of SAHA and Quinacrine Is Effective in Inducing Cancer Cell Death in Upper Gastrointestinal Cancers

Purpose: We aimed to investigate the therapeutic efficacy of single agent and the combination of quinacrine and suberoylanilide hydroxamic acid (SAHA) in wt- and mut-p53 upper gastrointestinal cancer (UGC) cell models.Experimental Design: ATP-Glo, clonogenic cell survival, Annexin V, comet, DNA double-strand breaks (DSBs), qPCR, and Western blot analysis assays were utilized.Results: Using clonogenic cell survival, ATP-Glo cell viability, Annexin V, and sub-G₀ population analysis, we demonstrated that a combination of quinacrine and SAHA significantly decreased colony formation and increased cancer cell death (range, 4-20 fold) in six UGC cell models, as compared with single-agent treatments, irrespective of the p53 status (P < 0.01). The combination of quinacrine and SAHA induced high levels of DSB DNA damage (>20-fold, P < 0.01). Western blot analysis showed activation of caspases-3, 9, and γ-H2AX in all cell models. Of note, although quinacrine treatment induced expression of wt-p53 protein, the combination of quinacrine and SAHA substantially decreased the levels of both wt-P53 and mut-P53. Furthermore, cell models that were resistant to cisplatin (CDDP) or gefitinib treatments were sensitive to this combination. Tumor xenograft data confirmed that a combination of quinacrine and SAHA is more effective than a single-agent treatment in abrogating tumor growth in vivo (P < 0.01).Conclusions: Our novel findings show that the combination of quinacrine and SAHA promotes DNA damage and is effective in inducing cancer cell death, irrespective of p53 status and resistance to CDDP or gefitinib in UGC models. Clin Cancer Res; 24(8); 1905-16. ©2018 AACR.

Repurposing the anti-malarial drug, quinacrine: new anti-colitis properties

Background

Ulcerative colitis (UC) is a chronic inflammatory bowel disease that is associated with an increased risk of colorectal cancer in 8-10 years after disease onset. Current colitis treatment strategies do not offer a cure for the disease, but only treat the symptoms with limited success and dangerous side-effects. Also, there is no preventive treatment for either UC or colorectal cancer. Quinacrine is an anti-malarial drug with versatile use in the treatment of diseases involving inflammatory response such as rheumatoid arthritis and lupus erythematosus. It also has putative anti-cancer effect. Quinacrine's anti-inflammatory, anti-oxidant properties, and anti-tumorigenic properties make it a potential small molecule preventive agent for both UC and associated colorectal cancer.

Results

There were obvious changes in the CDI, histology, and inflammatory load in quinacrine-treated groups in a dose and time dependent manner in both models of UC, induced by chemical or haptenating agent.

Methods

We tested quinacrine at two different doses as a colitis treatment agent in two mouse models of UC - the dextran sulfate sodium and oxazolone. The clinical disease index (CDI), histological changes of the colon, levels of inflammatory markers (Cox-2, iNOS, p53) and overall health vitals were evaluated.

Conclusions

We demonstrate that quinacrine successfully suppresses colitis without any indication of toxicity or side-effects in two mouse models of UC.

Anticancer effect of quinacrine on diffuse large B‑cell lymphoma via inhibition of MSI2‑NUMB signaling pathway

Diffuse large B‑cell lymphoma (DLBCL) is the most common subtype of non‑Hodgkin's lymphoma. Despite improvements in the clinical outcomes of DLBCL, ~30% of patients will develop relapse/refractory disease. Therefore, novel therapeutic drugs have been investigated to improve disease outcomes. Previous studies have revealed the anticancer effects of quinacrine (QC) on tumor cells in vitro, although its role in human DLBCL is yet to be identified. The present study sought to examine the cytotoxic effect of QC on DLBCL cells. QC induced G0/G1 cell cycle arrest and apoptosis in the DLBCL cell lines SU‑DHL‑8 and OCI‑LY01, in a dose‑dependent manner, in addition to the downregulation of cyclin‑dependent kinase 4/6 and the upregulation of cleaved poly‑ADP ribose polymerase 1. Upon exposure to QC, RNA‑binding protein Musashi homolog 2 inactivation and activation of protein numb homolog were observed. In addition, QC was able to inhibit the expression of Myc proto‑oncogene protein. The results of the present study indicated that QC may be a potential anti‑DLBCL drug.

Quinacrine Inhibits ICAM-1 Transcription by Blocking DNA Binding of the NF-κB Subunit p65 and Sensitizes Human Lung Adenocarcinoma A549 Cells to TNF-α and the Fas Ligand

Quinacrine has been used for therapeutic drugs in some clinical settings. In the present study, we demonstrated that quinacrine decreased the expression of intercellular adhesion molecule-1 (ICAM-1) induced by tumor necrosis factor (TNF)-α and interleukin-1 (IL-1) α in human lung adenocarcinoma A549 cells. Quinacrine inhibited ICAM-1 mRNA expression and nuclear factor κB (NF-κB)-responsive luciferase reporter activity following a treatment with TNF-α and IL-1α. In the NF-κB signaling pathway, quinacrine did not markedly affect the TNF-α-induced degradation of the inhibitor of NF-κB or the TNF-α-induced phosphorylation of the NF-κB subunit, p65, at Ser-536 and its subsequent translocation to the nucleus. In contrast, a chromatin immunoprecipitation assay showed that quinacrine prevented the binding of p65 to the ICAM-1 promoter following TNF-α stimulation. Moreover, TNF-α and the Fas ligand effectively reduced the viability of A549 cells in the presence of quinacrine only. Quinacrine down-regulated the constitutive and TNF-α-induced expression of c-FLIP and Mcl-1 in A549 cells. These results revealed that quinacrine inhibits ICAM-1 transcription by blocking the DNA binding of p65 and sensitizes A549 cells to TNF-α and the Fas ligand.

Quinacrine induces the apoptosis of human leukemia U937 cells through FOXP3/miR-183/β-TrCP/SP1 axis-mediated BAX upregulation

Quinacrine, which is clinically used as an antimalarial drug, has anti-cancer activity. However, mechanism underlying its cytotoxic effect remains to be completely elucidated. In the present study, we investigated the cytotoxic effect of quinacrine on human leukemia U937 cells. Quinacrine-induced apoptosis of U937 cells was accompanied with ROS generation, mitochondrial depolarization, and BAX upregulation. Quinacrine-treated U937 cells showed ROS-mediated p38 MAPK activation and ERK inactivation, which in turn upregulated FOXP3 transcription. FOXP3-mediated miR-183 expression decreased β-TrCP mRNA stability and suppressed β-TrCP-mediated SP1 degradation, thus increasing SP1 expression in U937 cells. Upregulated SP1 expression further increased BAX expression. BAX knock-down attenuated quinacrine-induced mitochondrial depolarization and increased the viability of quinacrine-treated cells. Together, our data indicate that quinacrine-induced apoptosis of U937 cells is mediated by mitochondrial alterations triggered by FOXP3/miR-183/β-TrCP/SP1 axis-mediated BAX upregulation.

Quinacrine in endometrial cancer: Repurposing an old antimalarial drug

OBJECTIVE

Generate preclinical data on the effect of quinacrine (QC) in inhibiting tumorigenesis in endometrial cancer (EC) in vitro and explore its role as an adjunct to standard chemotherapy in an EC mouse model.

METHODS

Five different EC cell lines (Ishikawa, Hec-1B, KLE, ARK-2, and SPEC-2) representing different histologies, grades of EC, sensitivity to cisplatin and p53 status were used for the in vitro studies. MTT and colony formation assays were used to examine QC's ability to inhibit cell viability in vitro. The Chou-Talalay methodology was used to examine synergism between QC and cisplatin, carboplatin or paclitaxel. A cisplatin-resistant EC subcutaneous mouse model (Hec-1B) was used to examine QC's role as maintenance therapy.

RESULTS

QC exhibited strong synergism in vitro when combined with cisplatin, carboplatin or paclitaxel with the highest level of synergism in the most chemo-resistant cell line. Neither QC monotherapy nor carboplatin/paclitaxel significantly delayed tumor growth in xenografts. Combination treatment (QC plus carboplatin/paclitaxel) significantly augmented the antiproliferative ability of these agents and was associated with a 14-week survival prolongation compared to carboplatin/paclitaxel. Maintenance with QC resulted in further delay in tumor progression and survival prolongation compared to carboplatin/paclitaxel. QC was not associated with weight loss and the yellow skin discoloration noted during treatment was reversible upon discontinuation.

CONCLUSIONS

QC exhibited significant antitumor activity against EC in vitro and was successful as maintenance therapy in chemo-resistant EC mouse xenografts. This preclinical data suggest that QC may be an important adjunct to standard chemotherapy for patients with chemo-resistant EC.

Trefoil factor family 2 expression inhibits gastric cancer cell growth and invasion in vitro via interactions with the transcription factor Sp3

The trefoil factor family (TFF) is a group of short secretory peptides of gastric mucous neck cells. The loss of TFF2 protein expression enhances gastric inflammation and occurs in gastric cancer. In this study, we examined the effect of TFF2 on gastric cancer cell lines in vitro and characterized the interaction between TFF2 and Sp3, including the mechanisms that mediate this interaction, using genomics and proteomics approaches, as well as genetics techniques, such as RNA interference and gene knockdown. Assays were performed to examine the role of TFF2 and Sp3 in cancer cell proliferation, invasion and migration. We found that TFF2 expression inhibited the proliferation and invasion capacity of gastric cancer cells, and induced apoptosis. TFF2 interacted with the Sp3 protein, as shown by immunofluorescence staining and immunoprecipitation with western blot analysis. Sp3 knockdown in gastric cancer cells antagonized TFF2 anti-tumor activity. Additionally, TFF2 upregulated the expression of pro-apoptotic proteins, such as Bid, but downregulated the expression of NF-κB and the anti-apoptotic proteins, Bcl-xL and Mcl-1. By contrast, Sp3 knockdown significantly blocked TFF2 activity, affecting the expression of these proteins. The data from our study demonstrate that the antitumor activity of TFF2 is mediated by an interaction with the Sp3 protein in gastric cancer cells. Additional in vivo and ex vivo warrned in order to fully characterize this interaction.

Inhibition of the NF-κB pathway by nafamostat mesilate suppresses colorectal cancer growth and metastasis

Nafamostat mesilate is an anti-inflammatory drug that is usually used to treat pancreatitis. Recent studies show that it can suppress pancreatic cancer via inhibition of the nuclear factor κB (NF-κB) pathway. However, whether it has anti-tumor activity in some other cancer, including colorectal cancer (CRC), has not been investigated and remained unclear. Here, our study showed that nafamostat mesilate abrogated the constitutive NF-κB activation in CRC cells, which is mediated through inhibition of phosphorylation of IκBα and nuclear translocation of p65. Also, we found that nafamostat mesilate inhibited phosphorylation of Erk in CRC cells. Consistently, our study demonstrated that nafamostat mesilate inhibited the CRC cell proliferation, invasion and migration and induced mitochondria-dependent apoptosis. Furthermore, nafamostat mesilate could reverse oxaliplatin induced NF-κB and Erk activation in CRC cells, and enhance the sensitivity of CRC cells to oxaliplatin. Nafamostat mesilate combined with oxaliplatin repressed subcutaneous tumor growth and hepatic metastasis in vivo. Overall, our data suggest that nafamostat mesilate, a relatively non-toxic drug that targets NF-κB and Erk, may, in combination with oxaliplatin, represent a novel therapeutic strategy for CRC treatment.

Curcumin mediates oxaliplatin-acquired resistance reversion in colorectal cancer cell lines through modulation of CXC-Chemokine/NF-κB signalling pathway

Resistance to oxaliplatin (OXA) is a complex process affecting the outcomes of metastatic colorectal cancer (CRC) patients treated with this drug. De-regulation of the NF-κB signalling pathway has been proposed as an important mechanism involved in this phenomenon. Here, we show that NF-κB was hyperactivated in in vitro models of OXA-acquired resistance but was attenuated by the addition of Curcumin, a non-toxic NF-κB inhibitor. The concomitant combination of Curcumin + OXA was more effective and synergistic in cell lines with acquired resistance to OXA, leading to the reversion of their resistant phenotype, through the inhibition of the NF-κB signalling cascade. Transcriptomic profiling revealed the up-regulation of three NF-κB-regulated CXC-chemokines, CXCL8, CXCL1 and CXCL2, in the resistant cells that were more efficiently down-regulated after OXA + Curcumin treatment as compared to the sensitive cells. Moreover, CXCL8 and CXCL1 gene silencing made resistant cells more sensitive to OXA through the inhibition of the Akt/NF-κB pathway. High expression of CXCL1 in FFPE samples from explant cultures of CRC patients-derived liver metastases was associated with response to OXA + Curcumin. In conclusion, we suggest that combination of OXA + Curcumin could be an effective treatment, for which CXCL1 could be used as a predictive marker, in CRC patients.

2'-Hydroxy-4-methylsulfonylchalcone enhances TRAIL-induced apoptosis in prostate cancer cells

Prostate cancer is the most common malignant cancer in men and the second leading cause of cancer deaths. Previously, we have shown that 2'-hydroxy-4-methylsulfonylchalcone (RG003) induced apoptosis in prostate cancer cell lines PC-3 and DU145. Although tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent, some cancer cells are resistant to TRAIL treatment. PC-3 and LNCaP prostatic cancer cell lines have been reported to be resistant to TRAIL-induced apoptosis. Here, we show for the first time that RG003 overcomes TRAIL resistance in prostate cancer cells. RG003 can enhance TRAIL-induced apoptosis through DR5 upregulation and downregulation of Bcl-2, PI3K/Akt, NF-κB, and cyclooxygenase-2 (COX-2) survival pathways. When used in combined treatment, RG003 and TRAIL amplified TRAIL-induced activation of apoptosis effectors and particularly activation of caspase-8 and the executioner caspase-3, leading to increased poly-ADP-ribose polymerase cleavage and DNA fragmentation in prostate cancer cells. Furthermore, we showed that RG003 reduced COX-2 expression in cells. Previously, we showed that COX-2 was involved in resistance to an apoptosis mechanism; then, its inhibition by RG003 could render cells more sensitive to TRAIL treatment. We showed that nuclear factor-κB activation was inhibited after RG003 treatment. This inhibition was correlated with reduction in COX-2 expression and induction of apoptosis. Overall, we conclude, for the first time, that RG003 can enhance TRAIL-induced apoptosis in human prostate cancer cells. The significance of our in-vitro study with RG003 and TRAIL combined is very encouraging, suggesting the relevance of testing this combined treatment in xenograft animal models.

Icariin-mediated inhibition of NF-κB activity enhances the in vitro and in vivo antitumour effect of 5-fluorouracil in colorectal cancer

Colorectal cancer (CRC) is an aggressive malignancy that has a poor prognosis. 5-Fluorouracil (5-FU) is a first line chemotherapeutic medication used in the treatment of gallbladder cancer; however, the efficacy is below satisfactory. Icariin is a natural compound that is conventionally reported to have activity against a variety of cancers. This study was carried out to investigate the anti-cancer effect of icariin in CRC cells and to determine whether the compound can enhance the antitumour activity of 5-FU. Cell proliferation and apoptosis were measured using an MTT assay and flow cytometry, respectively. The activity of transcription factor NF-κB was determined by EMSA method. The expression of apoptosis- and proliferation-related proteins was determined by western blotting. The in vivo antitumour effect of combination treatment with icariin and 5-FU on CRC was also assessed using a murine model of CRC. Icariin sensitized the CRC cells to 5-FU both in vitro and in vivo. The antitumour activity of icariin and its potentiating effect on the antitumour activity of 5-FU implicated the suppression of NF-κB activity and consequent down-regulation of the gene products regulated by NF-κB. Our results showed that icariin, suppressed tumour growth and enhanced the antitumour activity of 5-FU in CRC by inhibiting NF-κB activity. Therefore, we suggest that combination of icariin with 5-FU might offer a therapeutic benefit to the patients with CRC; however, further studies are required to ascertain this proposition.

Tumor-Related Molecular Mechanisms of Oxaliplatin Resistance

Oxaliplatin was the first platinum drug with proven activity against colorectal tumors, becoming a standard in the management of this malignancy. It is also considered for the treatment of pancreatic and gastric cancers. However, a major reason for treatment failure still is the existence of tumor intrinsic or acquired resistance. Consequently, it is important to understand the molecular mechanisms underlying the appearance of this phenomenon to find ways of circumventing it and to improve and optimize treatments. This review will be focused on recent discoveries about oxaliplatin tumor-related resistance mechanisms, including alterations in transport, detoxification, DNA damage response and repair, cell death (apoptotic and nonapoptotic), and epigenetic mechanisms.

Drug screen in patient cells suggests quinacrine to be repositioned for treatment of acute myeloid leukemia

To find drugs suitable for repositioning for use against leukemia, samples from patients with chronic lymphocytic, acute myeloid and lymphocytic leukemias as well as peripheral blood mononuclear cells (PBMC) were tested in response to 1266 compounds from the LOPAC¹²⁸⁰ library (Sigma). Twenty-five compounds were defined as hits with activity in all leukemia subgroups (<50% cell survival compared with control) at 10 μM drug concentration. Only one of these compounds, quinacrine, showed low activity in normal PBMCs and was therefore selected for further preclinical evaluation. Mining the NCI-60 and the NextBio databases demonstrated leukemia sensitivity and the ability of quinacrine to reverse myeloid leukemia gene expression. Mechanistic exploration was performed using the NextBio bioinformatic software using gene expression analysis of drug exposed acute myeloid leukemia cultures (HL-60) in the database. Analysis of gene enrichment and drug correlations revealed strong connections to ribosomal biogenesis nucleoli and translation initiation. The highest drug–drug correlation was to ellipticine, a known RNA polymerase I inhibitor. These results were validated by additional gene expression analysis performed in-house. Quinacrine induced early inhibition of protein synthesis supporting these predictions. The results suggest that quinacrine have repositioning potential for treatment of acute myeloid leukemia by targeting of ribosomal biogenesis.

Downregulation of osteopontin enhances the sensitivity of glioma U251 cells to temozolomide and cisplatin by targeting the NF-κB/Bcl‑2 pathway

Glioma is resistant to the apoptotic effects of chemotherapy and the mechanism underlying its chemoresistance is not currently understood. In a previous study, we reported that osteopontin (OPN) was overexpressed in glioma tissues and had an important anti‑apoptotic effect. Furthermore, overexpression of OPN was observed following chemotherapy. To elucidate whether OPN plays a role in chemotherapy resistance and to investigate its downstream signaling pathway, this study used small interfering RNA (siRNA) to silence the expression of OPN in U251 human neuronal glioma astrocytoma cells. OPN downregulation in U251 cells enhanced the apoptotic effects induced by temozolomide (TMZ) and cisplatin (DDP). Furthermore, OPN siRNA suppressed the nuclear factor κ‑light‑chain‑enhancer of activated B cells (NF‑κB) activation and B cell lymphoma 2 (Bcl‑2) expression that was induced by chemotherapy. Taken together, these results demonstrated that the expression levels of OPN are involved in glioma chemoresistance. Knockdown of OPN through siRNA enhanced the effects of TMZ and DDP chemotherapy by targeting the NF‑κB/Bcl‑2 pathway.