Anti-Cancer Agents in Medicinal Chemistry (Formerly Current Medicinal Chemistry - Anti-Cancer Agents) - Volume 18, Issue 3, 2018

Ras association domain family member 5 (RASSF5, also named NORE1) is an identified member of the RASSF gene family which could bind selectively to activate Ras and function as an antineoplastic effector in multiple cellular regulations. While highly expressed in majority of normal tissues, RASSF5 is epigenetically inactivated by promoter hypermethylation in numerous cancer cell lines and primary cancers, suggesting it as a potential tumor suppressor. Nevertheless, the physiologic significance of RASSF5 in tumorigenesis remains unclear. We performed a systematic literature review and assessment from PUBMED and MEDLINE databases in this article. RASSF5 is involved in a series of cellular responses including apoptosis, senescence, cell cycle regulation, differentiation and cell proliferation and the inactivation of RASSF5 has been implicated to participate in the oncogenesis, progression and poor prognosis of human cancers. In this review, we mainly elucidate the acknowledged structure, progress in the verified functions and research advances of RASSF5 and the probably relevant signaling pathways. Based on these evidences, potentiality of RASSF5 as a new therapeutic target for human cancers may play a significant role in future oncotherapy.

This review summarizes the reported molecular mechanisms underlying the antileukemic property of Sesquiterpene Lactones (SLs). This systematic review was registered in the PROSPERO database and conducted following the PRISMA Statements. The MeSH terms, Sesquiterpenes, Lactones and Leukemia were used in four databases (Pubmed, Web of Science, Scopus and Bireme). There were 281 studies selected, but after exclusions, due to replication (n = 172) or not following PECOS criteria (n = 24), 148 studies remained. Of the 148 articles, only 22 were submitted to quality assessment and were scored in high level if more than two techniques, to elucidate antileukemic properties, were described, and then data were extracted. The studies mostly used human leukemia cell lines including primary and established cells, with or without chemotherapy resistance. The SLs used were obtained principally from plants. The antileukemic properties of SLs were extracted from 22 high level studies. They included cell death induction, mainly by apoptosis, as well as cell differentiation, cell cycle disruption, leukemia cancer stem cell growth inhibition and NF-ΚB pathway inhibition; the latter is a promising therapeutic target for lymphoid malignancies. We concluded that, in spite of the necessity of better toxicological profile characterization of SLs, the antileukemic properties of these compounds support the proposal that the SLs are promising candidates for the treatment of leukemia.

Cancer is a multistep disease incorporating physical, chemical, environmental, metabolic and genetic factors, which play direct or indirect role in the induction and deterioration of cancer. Many of the platinum based drugs were synthesized but due to their systemic toxicity, broad spectrum of action, intrinsic and acquired drug resistivity, it has become necessary to search for the effective anticancer drugs with superior efficiency. Among non-platinum metal compounds with antitumor activity, organotin complexes have proven effective management of toxicity, specific targeted drug uptake by the cancerous cell line and significant potential in the pharmaceutical chemistry. So this article provides a critical review from 2010 onwards of the anticancer activity of the organotin complexes reported by the authors worldwide and explores the landmarks for their future projection as novel anticancer chemotypes with high therapeutic indices.

The marine natural products (MNPs) isolated from seaweeds-associated microbial communities have received substantial attention owing to their exceptional nutritional and pharmacology application, such as antiviral, anticancer, antiprotozoal, antifungal, and antibacterial properties and so on. Particularly, there are several MNPs that have been displayed attractive value for the development of novel anticancer agents. This review covers the literature published in the recent 5 years on the novel anticancer MNPs discovered originating from seaweeds, and focused on the chemistry and relative anticancer activities of new MNPs which categorize their source organisms. These seaweed-derived MNPs are categorized based on their origin as brown algae, red algae, cyanobacteria, chlorophyta and others.

There is now a considerable body of evidence for sildenafil possessing anticancer properties. In this article, we argue the case for testing sildenafil as a lung cancer therapy chemoadjuvant. Currently, lung cancer is a disease with insufficient treatment options, with only 20% of patients responding to systemic chemotherapy, and even incremental potential improvements should be explored. We review the literature concerning the biochemical, physiological and metabolic effects on cancer cells by sildenafil alone, and when combined with chemotherapeutic agents. Most studies have shown that sildenafil is cytotoxic to cancer cells, both as a monotherapy and as a chemoadjuvant. Sildenafil enhances cancer cell apoptosis when used as a chemoadjuvant both in vitro and in vivo. In particular, in rodent experiments sildenafil has decreased tumour size compared to chemotherapy alone. Sildenafil has also been proven as an agent to decrease drug-efflux by cancer cells and increases blood perfusion to lung tissue, which can potentially increase the dosage of chemotherapeutic agents delivered to lung cancer cells compared to healthy tissue. In addition, the proven clinical effects of sildenafil on other lung diseases suggest that it could improve other patient outcomes, such as right ventricular function and quality of life. Sildenafil may also extend the half-life of docetaxel and some small molecule inhibitors used in lung cancer treatment by acting as an inhibitor of CYP3A4. We conclude that the evidence strongly warrants clinical investigation into the use of sildenafil as an agent for the treatment of lung-cancer.

Background: Pancreatic cancer is one of the most aggressive and lethal cancers, with poor prognosis and high resistance to current chemotherapeutic agents. Therefore, new therapeutic strategies and targets are underscored. Propolis has been reported to exhibit a broad spectrum of biological activities including anticancer activity. Objective: This study was carried out to assess the possible efficacy of Algerian propolis on the antitumor effect of doxorubicin on human pancreatic cancer cell line (PANC-1). Methods: Modifications in cell viability, apoptosis and cell cycle progression, Pgp activity and intracellular accumulation of DOX were monitored to study the synergistic effect of Algerian propolis on the antitumor effects of DOX in PANC-1 cell line. Results: Both propolis and its combination with doxorubicin inhibited cell growth in a dose-dependent manner by inducing cell cycle arrest and apoptosis. In the presence of 100 μg/ml of propolis, the IC50 of DOX against PANC-1 cells decreased by 10.9-fold. Propolis combined with DOX increased after 48h, the number of cells in the G0G1 phase with dramatical increase in sub-G1 phase to reach 47% of total cells, corresponding to an increase of senescence or apoptotic state of the cells. Dead cell assay with annexinV/PI staining demonstrated that propolis and propolis-DOX treatment resulted in a remarkable induction of apoptosis as detected by flow cytometry. It was interesting to note that propolis at its 5IC50 was found as the most potent inducer of apoptosis. Our finding revealed that induced apoptosis in our conditions was caspase-3 and caspase-9 dependent. Flow cytometry showed that propolis increased the accumulation of doxorubicin within PANC-1 cells. Moreover, fluorescent intensity detection revealed that propolis remarkably increased the retention of rhodamine-123, 7- fold compared to 3-fold of verapamil, the most effective P-gp inhibitor. Conclusion: In conclusion, propolis sensitize pancreatic cancer cells to DOX via enhancing the intracellular retention of DOX due to blocking the efflux activity of P-gp pump, inducing cell cycle arrest and increasing apoptosis, finding that improuve the synergism of antitumor effect of Algerian propolis and DOX in pancreatic cancer cell line. Therefore, Algerian propolis may be an effective agent in a combined treatment with doxorubicin for increased therapeutic efficacy against pancreatic cancer.

Background: CXC Chemokine Receptor 4 (CXCR4) and NFE–related factor 2 (Nrf2) have been observed implicated with cell malignant behavior of human cancers. Aims: In this study, we detected their expression in gastric carcinoma (GC) tissue specimens and related the result with clinicopathological data and patient survival. Methods: 120 GC and compared normal tissue specimens were processed to analyse the expression of CXCR4 and Nrf2. We found that the expression of CXCR4 and Nrf2 was dramatically increased in GC tissues when compared to the distant non-cancer tissues (P<0.05). CXCR4 overexpression was associated with the depth of invasion (P= 0.006) Histological grade (P=0.018) TNMstage (P= 0.021) lymph node metastasis (P < 0.001) and distant metastasis (P=0.026), whereas overexpression of Nrf2 protein was significantly associated with tumor size (P=0.045), Histological grade (P=0.026), TNMstage (P= 0.020), lymph node metastases (P < 0.001) and distant metastasis (P=0.008). Furthermore, we observed a significant co-expression of CXCR4 and Nrf2 expression in GC specimens. Results: In the survival part, we found that GC patients with CXCR4+ and Nrf2+ had worse outcomes. The significant prognostic indicators are age, tumor size, histological grade, TNMstage, CXCR4, Nrf2, and coexpression of CXCR4 and Nrf2 in GC patients. Multivariate analysis showed that TNMstage and CXCR4+/Nrf2+ expression were risk factors. Above all we come to the conclusion that the expression of CXCR4 might partly be regulated by the level of Nrf2 and both positive expressions suggest poor prognosis of GC patients.

Background: A broad range of metal-coordinated complexes have been studied for their anticancer activities. However, some of these complexes display high toxicity profiles to non-malignant cells, therefore limiting their use in cancer therapeutics. Aims/Method: Several silver(I) triphenylphosphine adducts were prepared as 1:1 to 1:4 ratios of silver nitrate to triphenylphosphine. They were further used to determine their anticancer activity in a malignant SNO esophageal cell line. The silver(I) phosphine adducts include: [Ag(PPh3)]NO3 (1); [Ag(PPh3)2]NO3 (2); [Ag(PPh3)3]NO3 (3) and [Ag(PPh3)4]NO3 (4). In addition, the activity of complexes 1-4 was compared to previously reported complexes [Ag(Ph2P(CH2)2PPh2)2]NO3 (5) and [Ag(Ph2P(CH2)3PPh2)2]NO3 (6). The cytotoxicity of complexes 1-6 was also evaluated in non-malignant human dermal fibroblast cells (HDF-a). Results: The majority of the complexes (specifically those containing PPh3) were found to be highly toxic to the SNO cells and less toxic towards HDF-a cells, as determined by the alamarBlue® assay. Morphological studies and flow cytometry confirmed that the silver(I) complexes induced apoptosis in the malignant cells. Conclusion: These results may have an impact on research related to drug discovery and silver(I) phosphine complexes could be added to the arsenal of anticancer agents in addition to the silver-bis-diphenylphosphinoethane and silver-bis-diphenylphosphinopropane adducts.

Background: Retinoids are important agents for the treatment of cutaneous T-cell lymphomas (CTCL). But side effects and drug resistance caused by activation of RAR/RXR limited their clinical application. Therefore, it is urgent to develop new agents to fight against CTCL. ECPIRM, a 13-cis retinoic acid derivative, was reported that it inhibited proliferation and induced apoptosis of SCL-1 cells. Objective: The aim of this study was to evaluate the biological activities and mechanisms of ECPIEM. Methods: The effect of ECPIRM on cell proliferation was determined by MTT assay and Trypan blue exclusion assay while FACS analysis was used to detect changes in cell cycle and apoptosis in HUT78 cells. The influence of ECPIRM on RAR/RXR and JAK/STAT signaling was evaluated by western blot analysis. Results: ECPIRM, better than other agents (all-trans retinoic acid,13-cis-retinoic acid or bexarotene), inhibited proliferation and induced apoptosis significantly in HUT78 cells, but with little cytotoxicity on normal lymphocytes. Then ECPIRM induced G0/G1 phase arrest by decreasing the expression of cyclinD1, cyclinE, CDK2 and CDK4 while increasing p21. Furthermore, the unaffected expression of RAR and RXR members suggested that ECPIRM acted independently of RAR/RXR pathway in HUT78 cells. But decreased phosphorylation of JAK1, STAT3, STAT5 and downregulated Bcl-xL, Cyclin D1 and c-Myc indicated that ECPIRM inhibited the activation of JAK/STAT signaling. Conclusion: ECPIRM inhibited proliferation, induced apoptosis and G0/G1 phase arrest in HUT78 cells through inhibiting JAK/STAT pathway but not RAR/RXR pathway, which presented ECPIRM as a promising candidate for the treatment of CTCL patients.

Introduction: Epidemiological studies indicate that diet rich in fruits and vegetables is associated with decreased cancer risk thereby indicating that dietary polyphenols can be potential chemo-preventive agents. The reversible nature of epigenetic modifications makes them a favorable target for cancer prevention. Polyphenols have been shown to reverse aberrant epigenetic patterns by targeting the regulatory enzymes, DNA methyltransferases (DNMTs) and histone deacetylases (HDACs). In vitro and in silico studies of DNMTs and HDACs were planned to examine genistein’s role as a natural epigenetic modifier in human cervical cancer cells, HeLa. Methods: Expression of the tumour suppressor genes (TSGs) [MGMT, RARβ, p21, E-cadherin, DAPK1] as well the methylation status of their promoters were examined alongwith the activity levels of DNMT and HDAC enzymes after treatment with genistein. Expression of DNMTs and HDACs was also studied. In-silico studies were performed to determine the interaction of genistein with DNMTs and HDACs. Results: Genistein treatment significantly reduced the expression and enzymatic activity of both DNMTs and HDACs in a time-dependent way. Molecular modeling data suggest that genistein can interact with various members of DNMT and HDAC families and support genistein mediated inhibition of their activity. Timedependent exposure of genistein reversed the promoter region methylation of the TSGs and re-established their expression. Conclusions: In this study, we find that genistein is able to reinstate the expression of the TSGs studied by inhibiting the action of DNMTs and HDACs. This shows that genistein could be an important arsenal in the development of epigenetic based cancer therapy.

Background: 2-Methoxystypandrone (2-MS), isolated from the roots of Polygonum cuspidatum, is a potent dual inhibitor of the STAT3 and NF-ΚB pathways. Objective: To investigate the molecular targets and mechanisms of 2-MS. Method: A biotin-conjugated 2-MS analog, named 2-MS-Biotin, was designed and synthesized. The effects of 2-MS-Biotin on the STAT3 and NF-ΚB pathways were examined by Western blotting. The cytotoxicity of 2- MS-Biotin was evaluated using real-time cell analysis system. Proteins directly bound to 2-MS-Biotin were pulled down through streptavidin agarose beads and were detected using Western blotting. Results: 2-MS-Biotin retained the inhibition activities of the parent compound 2-MS on the STAT3 and NF-ΚB pathways as well as on cancer cell growth. Also, JAK2 and IKK proteins can be effectively pulled down by 2- MS-Biotin. Conclusion: Using 2-MS-Biotin as a tool, both JAK2 and IKK were identified as the targets of 2-MS.

Background: Colon cancer is the second most common cancer to cause death worldwide. About half of colon cancers patients require adjuvant therapy to control relapse following surgical resection. Therefore, abolition of tumor cell progression using an effective chemotherapeutic agent holds a feasible approach to treat patients suffering from colon cancer. In the present study, we evaluated the effects of geranylated flavonoid CJK-7, isolated from Paulownia tomentosa on HCT-116 human colon carcinoma cells. Materials and Methods: The effects of CJK-7 as an active component on HCT-116 cells programmed cell death and its underlying molecular mechanism were examined by using MTT assay, morphological assessment, H2DCFDA staining, Fura-2AM staining, Hoechst-33342 staining, comet assay, Acridine orange staining, mitochondrial membrane potential (ΔΨm) assay and Western blot analyses. Results and Conclusion: The results revealed that, CJK-7 was capable of inducing caspase-dependent cell death events in cancer cells. Moreover, it was involved in up-regulation of autophagy signaling as evidenced by enhanced expression of LC3I/II. We also noticed stimulated expression of endoplasmic reticulum stress markers and phosphorylation of c-Jun NH2-terminal kinase (JNK), which was associated with up-regulated expression of p53, PUMA, Atg5 and Beclin-1, and down-regulation of Bcl-2, stressing the interaction of ROS on the aforementioned signaling. Furthermore, exposure to ROS scavengers (N-acetyl-l-cysteine (NAC), and JNK-specific inhibitor SP600125) significantly reversed the effects of CJK-7 by down-regulating apoptosis and autophagy signatures in HCT-116 cancer cells. Collectively our findings clarify the ROS-dependent regulatory effect of CJK-7 on programmed cell death signaling events in HCT-116 cancer cells while depicting its virile pro-oxidant capacity.

Objective: To study the effects of ultrasound irradiation on the release profile of 5-fluorouracil (5-Fu) loaded magnetic poly lactic co-glycolic acid (PLGA) nanocapsules. Also, the controlled drug-release behaviour of the nanocapsules was mathematically investigated. Methods: The nanocapsules were synthesized, dispersed in phosphate buffered saline (PBS), transferred to a dialysis bag, and finally, irradiated by various ultrasound parameters (1 or 3MHz; 0.3-1W/cm2; 5-10 minutes). The release profile of the irradiated nanocapsules was recorded for 14 days. To find the in vitro drug release mechanism in the absence and presence of various intensities of ultrasound, the obtained data were fitted in various kinetic models for drug release. Results: The results demonstrated that the ultrasound speeded up the rate of drug release from the nanocapsules. The mathematical analysis illustrated that when the ultrasound intensity is increased, the probability of controlled release behaviour of the nanocapsules is raised. We found that drug release from the irradiated nanocapsules follows an erosion-controlled mechanism with the decrease in the velocity of diffusion. Conclusion: In conclusion, to attain a controlled drug-delivery strategy in the area of cancer therapy, the drug release profile of the nano-carriers may be well-controlled by ultrasound.

Background: Coumarin is a natural phytochemical but as such has no medical uses. However, various natural and synthetic coumarin analogs attract attention due to their interesting biological properties. Objective: Here, we evaluated and compared anticancer properties of a new synthetic hybrid compound AD- 013, which integrates a coumarin moiety and an α-methylene-δ-lactone motif, with novobiocin, a natural antibiotic bearing a coumarin scaffold. Methods: Cytotoxic activities of compound AD-013 and novobiocin were assessed by the MTT assay. In order to explore the mechanism of anticancer activity of analog AD-013, we performed quantitative real-time PCR analysis of apoptosis- and cell cycle-related genes. The ability of AD-013 and novobiocin to induce apoptosis and DNA damage was studied by flow cytometry. Results: The cytotoxic activity of this new compound was compared with the activity of a coumarin-based antibiotic novobiocin against two cancer cell lines, MCF-7 and HL-60 and also against normal human cells, MCF- 10A and HUVEC. AD-013 was much more cytotoxic than novobiocin in both cancer cell lines and showed some selectivity against MCF-7 cancer cells as compared with MCF-10A healthy cells. Expression levels of the pro-apoptotic genes significantly increased while the anti-apoptotic genes, were down-regulated for both compounds in both cancer cell lines. AD-013 was able to inhibit cell proliferation, generate DNA damage and induce apoptosis. The obtained data showed that this compound caused the cell cycle arrest in subG0/G1 in both cancer cell lines. Conclusion: The new hybrid analog was a much stronger apoptosis inducer than novobiocin and activated the intrinsic pathway of apoptosis.

Background and Objective: Chemokine (C-C motif) ligand (CCL)2, the prototype Th2 chemokine, is secreted by tumor cells, and has growth promoting effects. Whether CCL2 protumorigenic activities will be validated, then CCL2 and its receptor CCR2 may be therapeutic targets in cancer. Methods: We tested in “primary human anaplastic thyroid carcinoma (ATC) cells” (ANA) versus “normal thyroid follicular cells” (TFC): a) CCL2 secretion basally, after IFN-γ and/or TNF-α stimulation; b) PPARγ activation by thiazolidinediones (TZDs), rosiglitazone or pioglitazone, on CCL2 secretion, and on proliferation and apoptosis in ANA. Results: ANA produced basally CCL2, at a higher level versus TFC. IFN-γ or TNF-α dose-dependently induced the CCL2 release in 3/6 or 5/6 ANA, respectively, but in all TFC. IFN-γ+TNF-α induced a synergistic release of CCL2 in all TFC, but only in 1/6 ATC. TZDs exerted an inhibition of CCL2 release in 3/6 ANA, while had no effect in TFC. Pioglitazone inhibition of ANA proliferation was not associated with the effect on CCL2; NF-ΚB and ERK1/2 were basally activated in ANA, increased by IFN-γ+TNF-α, and pioglitazone inhibited IFN- γ+TNF-α activation. CCL2 serum levels were higher in 6 ATC patients than in 5 controls (813±345 versus 345±212, pg/mL; respectively; P<0.01, ANOVA). Conclusion: ANA produce CCL2 basally and after cytokines stimulation, with an extremely variable pattern of modulation, suggesting different types of deregulation in the chemokine modulation. Serum CCL2 is increased in ATC patients. Further studies will be necessary to evaluate if CCL2 might be used as a marker in the followup of ATC patients.