Anti-Cancer Agents in Medicinal Chemistry (Formerly Current Medicinal Chemistry - Anti-Cancer Agents) - Volume 17, Issue 7, 2017

The CD30 antigen is strongly expressed on neoplastic cells in classical Hodgkin lymphoma (HL), anaplastic large cell lymphoma (ALCL) and other hematologic malignancies (such as DLBCL and cutaneous TCL), while is almost undetectable on healthy tissues, representing an ideal immunotherapeutic target. Since unconjugated anti-CD30 antibody (SGN-30) demonstrated limited clinical activity, researchers’ effort aimed to create an antibody-drug conjugate (ADC), leading to discovery of SGN-35 (brentuximab vedotin), in which an anti-CD30 antibody is linked to the antimitotic agent monomethyl auristatin E (MMAE). In the first phase I study in CD30+ hematologic malignancies (the majority of patients with HL), the maximum tolerated dose was fixed respectively at 1.8mg/Kg every 3 weeks, overall response rate (ORR) and complete response (CR) rate were 38% and 24%. In 2 subsequent phase II studies, amazing results were reported, that permitted accelerated FDA approval for relapsed/refractory patients and led to the development of many clinical trials including BV as first-line HL and ALCL treatment. Moreover, as CD30 antigen may be expressed by other malignancies, the potential therapeutic application is increasing, including at least diffuse large B-cell lymphoma, T-cell lymphomas other than ALCL and cutaneous lymphoproliferative disorders. BV is administrated as outpatient regimen and is usually well tolerated; sensorial peripheral neuropathy represents the most common toxic effect, although it is dose-dependent and at least partially reversible in most cases, after dose reduction and/or treatment ending.

Background: Deleted in liver cancer 1 (DLC-1) In human was originally isolated from rats brain and was often found to be deleted in hepatocellular carcinoma (HCC). Methods: We undertook a structured search of bibliographic databases for peer-reviewed research literature using a focused review question and inclusion/exclusion criteria. Results: Subsequent studies have demonstrated that DLC-1 is generally expressed in normal human tissues as well as in rats, while it always exists inactivated or even lost in many human cancers, which characterizes DLC-1 as a potential tumor suppressor. Additionally, the RhoGAP (Rho-GTPase activating proteins) activity was found to play a pivotal role in regulating DLC-1. Conclusion: Although emerging studies in a variety of cancers have identified DLC-1 and its downstream signaling molecules as potential therapeutic targets for treatments of DLC-1-related cancers, the mechanisms linked to DLC-1 remain undefined.

Neuroendocrine tumors (NETs) are a diverse set of tumors, being genetically varied. NETs can be presented with a distinct clinical picture, due to the production of various hormones, or being silent. Based on community health clinical statistics, the frequency numbers and reported occurrence of NETs are increasing. Although the therapeutic options for NETs have expanded in recent years, clinical diagnosis is possible only when metastases are present, requiring chronic complicated medical management. A positive development is that the recent evolution of molecularly-targeted therapy in oncology promotes the evolution of innovative tools for the management of these tumors. A diverse assortment of medical specialists is needed to improve outcomes and orchestrate the therapeutic care plan for NET patients.

Bortezomib was the first proteasome inhibitor (PI) discovered and demonstrated great efficacy in myeloma, both in vitro and in patients. However, still many patients ultimately relapse and there is the need for novel therapies. A second generation of PI have been discovered, potentially more effective ands some also orally administered. Carfilzomib is an irreversible proteasome inhibitor that showed great efficacy in clinical studies. Ixazomib is an oral compound that has been introduced recently in the therapeutic spectrum. Novel agents such as Marizomib seem promising in the fact that can also pass through the blood brain barrier and maybe effective also in CNS muyeloma. This review focus on all proteasome inhibitors available in clinics and the new ones coming soon.

Background: Histone deacetylase 8 (HDAC8) is a plausible target for the development of novel anticancer drugs using a metal-chelating group and hydrophobic moieties as pharmacophores. It is known that valproic acid (administered as its salt, sodium valproate; VPANa+) is an HDAC8 inhibitor characterized by its hydrophobic chains. Nevertheless, VPA is hepatotoxic and VPA analogues might be explored for less hepatotoxic antiproliferative compounds. Method: In this work, docking and QSAR studies of 500 aryl-VPA derivatives as possible HDAC8 inhibitors were performed in order to explore and select potential anti-proliferative compounds. Docking results identified π−π, hydrogen bonds as the most important noncovalent interactions between HDAC8 (PDB: 3F07) and the ligands tested, whereas Belm4 was the best QSAR descriptor and classified as a 2D-BCUT descriptor. Result: Based on theoretical studies, compound DAVP042 was synthesized and evaluated in vitro for its antiproliferative activities on several cancer cell lines (A549-lung, MCF-7-breast, HCT116-colon and U937- lymphoid tissue) in comparison to VPA, as well as for its inhibitory activity on HDAC8 using in vitro models. DAVP042 demonstrated to have antiproliferative activity on all cancer cell lines employed, not only suggesting that this compound should be further studied, but also demonstrating that the methodology herein employed is appropriated to identify new therapeutic candidates.

Objective: To explore the function of miR-34a in promotion of apoptosis by SYB. Methods: In this study, the most effective concentration of SYB was determined by measuring cell proliferation. Relative miR-34a mRNA levels were detected by quantitative RT-PCR. Apoptosis was assessed using Annexin- V/PI assays, whereas protein levels of p53, caspase 3, caspase 9, caspase 8 and Bcl2 were evaluated by western blotting. Results: Minimum HepG2 cell growth was observed after 36h of exposure to 150 nmol/L SYB. miR-34a expression was highest 40min after the addition of SYB. SYB slightly decreased the abundance of Bcl-2, but increased the abundance of p53, caspase 3, caspase 9 and caspase 8. SYB failed to alter miR-34a expression when p53 was inhibited. Bcl-2 abundance remained low over time, whereas the abundance of caspase 3, caspase 9 and caspase 8 gradually increased. Inhibition of p53 promoted HepG2 cell growth in comparison with that of the control group. miR-34a was silenced to assess the role of miR-34a in the inhibitory effect of SYB on HepG2 cell growth. When p53 was silenced, protein abundance of Bcl2, caspase 3, caspase 8 and caspase 9 remained unchanged following the addition of SYB; moreover, HepG2 cell growth was increased. Conlusion: SYB represents a promising therapeutic approach for liver cancer patients.

Background: Recent investigations have implicated that Chitosan-nucleotide nanoparticles might be useful non-viral carriers in gene therapy. Polo-like kinase 1 (PLK1) has been reported to be an important oncogene that exerted considerable therapeutic merit in hepatocellular carcinoma (HCC). Objective: We explored whether Galactosylated chitosan-graft-poly(ethylene glycol) (GCP) nanoparticlemediated delivery of PLK1 siRNA nucleotides could serve as an effective anti-cancer agent for HCC therapy. Method: GCP nanoparticles were prepared to deliver PLK1 siRNA oligos into HCC cells and tissues. Real-time fluorescence quantitative PCR (RFQ-PCR) and western blotting analyses were used to examine the efficiency of nanoparticle-mediated depletion of PLK1 in HepG2 cells. Cell proliferation and apoptotic death were also examined using flow cytometric, MTT and TUNEL assays. Xenograft mouse model was conducted to assess the impact of GCP/siRNA nanoparticles on the in vivo growth of HCC cells. Results: GCP nanoparticles bind to PLK1 siRNA efficiently. The particle size and zeta potential of GCP/siRNA nanoparticles are suitable for cellular delivery. PLK1-targeting nanoparticles inhibited cell proliferation through inducing G2/M phase arrest with a higher efficacy than a selective and potent PLK1 inhibitor BI 2536. Moreover, TUNEL assay revealed that PLK1-siRNA nanoparticles induced apparent apoptosis in HepG2 cells. In addition, PLK1-targeting nanoparticles induced significant upregulation of cellular p53, Bax and p21, whereas the level of Bcl-2 was impaired in HCC cells. Moreover, PLK1-targeting nanoparticles impaired the tumorigenicity of HepG2 cells in vivo. Conclusion: These findings indicate that PLK1-targeting nanoparticles exert considerable therapeutic merit and GCP/siRNA nanoparticles would be a valuable therapeutic carrier for HCC.

Background: Studies have shown that the renin angiotensin system via angiogenesis is involved in tumor development. Objective: Therefore, objective of the present study was to examine the effect of perindopril on tumor growth and angiogenesis in animal models of breast cancer. Methods: In the present study, the effect of perindopril on tumor development of mammary gland cancer induced by 7,12-dimethylbenz[a]anthracene, mouse tumor xenograft and corneal micropocket model has been investigated. Anti-angiogenic effect by chick yolk sac membrane assay has also been studied. Results: In the present study, it has been found that perindopril produced a significant inhibition of tumor growth, in DMBA induced breast cancer. Treatment also produced significant suppression of cancer biomarkers such as lactate dehydrogenase, gamma glutamyl transferase and inflammatory markers such as C-reactive protein, erythrocyte sedimentation rate. Histopathological analysis also showed that perindopril was able to inhibit tumor development by the inhibition of hyperplastic lesions. Perindopril produced significant inhibition of tumor growth, in a mouse xenograft model and caused inhibition of neovascularization in the corneal micropocket model. In chick yolk sac membrane assay, perindopril showed inhibition of vascular growth and reduced blood vessel formation. Conclusion: Therefore, perindopril is widely used in clinical practice, may represent a neo-adjuvant therapy for treatment of breast cancer.

Background: The high rates of women's death from breast cancer occur due to acquired resistance by patients to certain treatments, enabling the recurrence and/or tumor growth, invasion and metastasis. It has been demonstrated that the presence of cancer stem cells in human tumors, as responsible for recurrence and resistance to therapy. Studies have identified OCT4 as responsible for self-renewal and maintenance of pluripotency of stem cells. Thus, it is interesting to study potential drugs that target this specific population in breast cancer. Melatonin, appears to have oncostatic effects on cancer cells, however, little is known about its therapeutic effect on cancer stem cells. Objective: Evaluate the viability and the expression of OCT4 in breast cancer stem cells, MCF-7 and MDA-MB- 231, after melatonin treatment. Method: The cells were grown in a 3-dimensional model of mammospheres, representing the breast cancer stem cell population and treated or not with melatonin. The cell viability of mammospheres were evaluated by MTT assay and the OCT4 expression, a cancer stem cells marker, was verified by immunocitochemistry. Results: Our results demonstrated that the melatonin treatment decreased the cell viability of MCF-7 and MDAMB- 231 mammospheres. Furthermore, it was observed that in both cell lines, the expression of OCT4 was decreased in melatonin-treated cells compared to the control group. Conclusions: This fact suggests that melatonin is effective against breast cancer stem cells inhibiting the cell viability via OCT 4. Based on that, we believe that melatonin has a high potential to be used as an alternative treatment for breast cancer.

Background: Earlier results from our group have shown that in pancreatic ductal adenocarcinoma (PDAC)-derived cells transforming growth factor (TGF)-β1-dependent epithelial-mesenchymal transition (EMT) and cell motility was inhibited by the Src inhibitors PP2 and PP1 both of which targeted the TGF-β receptors for inhibition. Objective: In this study we evaluated the impact of another Src inhibitor, AZM475271, on various TGF-β responses in PDAC cells. Method: The effect of AZM475271 on TGF-β1-induced random cell migration (chemokinesis), the expression of EMT and migration/invasion-associated genes, TGF-β-induced luciferase activity, and C-terminal phosphorylation of Smad2 and Smad3 was measured in the PDAC-derived Panc-1 and Colo357 cell lines using real-time cell migration assays, quantitative real-time PCR, luciferase reporter gene assays and phosphoimmunoblotting, respectively. Results: AZM475271 effectively blocked TGF-β1-induced chemokinesis of Panc-1 cells in a dose-dependent fashion and inhibited the high chemokinetic activity of Panc-1 cells with ectopic expression of a constitutively active ALK5T204D mutant. AZM475271 but not another Src inhibitor, SU6656, partially relieved the suppressive effect of TGF-β1 on E-cadherin and inhibited TGF-β1-induced upregulation of the MMP2, MMP9, N-cadherin and vimentin genes, activity of a TGF-β1-dependent reporter gene, and activation of Smad2 and Smad3. Conclusion: Our data suggest that AZM475271 cross-inhibits tumor-promoting TGF-β signaling and may thus function as an inhibitor of both TGF-β and Src in both experimental and clinical therapies against metastatic dissemination in late-stage PDAC.

Background: Protease activated receptor-1 (PAR1) is a G-coupled receptor activated by α-thrombin and other proteases. Several reports have demonstrated the PAR1 involvement in tumorigenesis and tumor progression. In order to investigate on potential use of PAR1 antagonists as antiproliferative agents. Aims: We have identified a series of arylpiperazine derivatives acting as PAR1 antagonists; the selected molecules have been evaluated for their antiproliferative properties. Method: All the compounds inhibited the growth of a panel of cell lines expressing PAR1; two of them, compounds 13 and 15, were able to inhibit, in a dose dependent manner, the growth of the selected cell lines with the lowest IC50 values, and were further characterized to define the mechanism responsible for the observed antiproliferative effect. Result: This study directed us to the identification of two interesting leads that may help to further validate PAR1 as an important therapeutic target for cancer treatment.

Backgroud: Pinoresinol (Pin) and pinoresinol monoglucoside (PMG) are plant-derived lignan molecules with multiple functions. We showed previously that an endophytic fungus from Eucommia ulmoides Oliv., Phomopsis sp. XP-8 is able to produce Pin and PMG. Objective: This study was carried out to test the anti-tumor capability of the culture of XP-8 and identify the major effective compounds. Method: The fungal culture was added in the culture of HepG2 and K562 cells, and the viabilities of these cells were detected and the possible mechanism was analyzed. Result: The fungal culture showed significant capaiblity in decreasing the viability of tumor cells and induce apoptosis via up-regulation of the expression of apoptosis-related genes. It also significantly inhibited the adhesion and migration of HepG2 cells by blocking MMP-9 expression. Pin and PMG were isolated from the growth culture and shown to be the major effective components for inhibition. Conclusion: The study indicated the potential application of XP-8 in the production of anti-tumour products by the bioconversion of glucose.

Objective: A series of novel 2,4-diaminosubstituted pyrrolo[3,2-d]pyrimidines was synthesized together with their corresponding 7-phenyl or 7-isopropyl counterparts. Results: Among the target derivatives, the 7-substituted analogues exhibited interesting cytotoxic activity against a panel of PI3Kα related human breast cancer cell lines, namely MCF7, T47D, MDA-MB-231 and HCC1954. Selected compounds were tested for potential PI3Kα inhibitory activity as well as for their cytotoxic effect in prostate cancer cell lines (DU145 and PC3). Conclusion: Derivatives bearing a specific substitution pattern consisting of 7-phenyl as well as a 2-(4- aminocyclohexylamino) moiety (16c, 16f) display kinase inhibitory activity, elucidated on the basis of molecular simulation studies, which revealed their interaction with the DFG motif of the kinase.

Aims: A series of 1,4-dihydropyridine based compounds bearing benzylpyridinium moiety have been designed and evaluated for in vitro anticancer activity against glioblastoma U87MG, lung cancer A549 and colorectal adenocarcinoma Caco-2 cell lines using the MTT assay. Method: Among these compounds, 7b, 7d, 7e, and 7f exhibited potent anticancer activity against the cell lines tested. The cytotoxicity of the synthesized derivatives was compared to standard drugs (carboplatin, gemcitabine, and daunorubicin). Result: Thus, synthesized 1,4-dihydropyridines can be considered as the encouraging molecules for further drug development as anticancer agents.

Aims: Pyrrole derivatives represent a very interesting class as biologically active compounds. The objective of our study was to investigate the cytotoxic and apoptotic effects and antioxidant activity of the newly synthesized pyrrole derivatives. Method: A series of novel pyrroles and fused pyrroles (tetrahydroindoles, pyrrolopyrimidines, pyrrolopyridines and pyrrolotriazines) were synthesized and characterized using IR, 1H NMR, 13C NMR, MS and elemental analysis techniques. The antiproliferative activity of our synthesized compounds and their modulatory effect apoptotic pathway were investigated. The effect on cellular proliferation and viability was monitored by resazurin assay. Apoptotic effect was evaluated by caspase glo 3/7 assay. Synthesized compounds are then tested for their anticancer activities against three different cell lines representing three different tumor types, namely; the HepG-2 (Human hepatocellular liver carcinoma cell line), the human MCF-7 cell line (breast cancer) and the pancreatic resistant Panc-1 cells. Result: Compounds Ia-e, IIe, and IXc, d showed a promising anti-cancer activity on all tested cell lines. Antioxidant and wound healing invasion assays were examined for promising anticancer candidate compounds.