Anti-Cancer Agents in Medicinal Chemistry (Formerly Current Medicinal Chemistry - Anti-Cancer Agents) - Volume 17, Issue 9, 2017

This paper reviews the nonclinical reproductive toxicity testing of 15 drugs currently approved in the USA or Europe for the treatment of cancer. The list includes cytotoxic anti-tumour agents, small molecule inhibitors of pathways involved in neoplastic proliferation, monoclonal antibodies that target specific antigens expressed by neoplastic cells and supportive therapies used to counter the effects of chemotherapy. Most, but not all, drugs were tested for developmental or reproductive toxicity in animals prior to marketing and most were found to be embryotoxic or teratogenic. Because of the unmet need for comparative safety data on available cancer therapies for use by physicians when treating pregnant patients, at least embryofetal toxicity studies are now usually requested prior to marketing of new anti-cancer drugs, even when the pharmacological profile suggests likely side-effects on the embryo or fetus. Rats and rabbits are the preferred experimental species, but non-human primates have to be used for some biopharmaceuticals. Nonclinical study designs for anti-cancer drugs should be designed to allow the possibility of terminating the study once adverse effects have been demonstrated, without using the full number of animals specified in regulatory guidelines. All 15 drugs are currently labelled as being harmful to pregnancy, ether on the basis of animal data or documented hazards in humans. It is hoped that the forthcoming revision of the FDA drug labelling legislation will allow a better graduation of the relative risk between available anti-cancer therapies.

Retinoic acid (RA), especially all-trans retinoic acid is the most potent natural metabolite of vitamin A. RA is involved in a variety of biological functions including embryogenesis, cell differentiation and apoptosis. RA acts through its nuclear receptors to induce transcription of specific target genes. Mouse P19 embryonic carcinoma (EC) stem cells (ES) are one of the most studied in vitro systems for RA-induced differentiation. P19 ES cells can differentiate to endodermal-like, mesodermal-like, and neuronal-like phenotypes in response to specific morphogens including RA and dimethyl sulfoxide (DMSO). At low concentrations, RA directs P19 ES cells to differentiate into cells displaying an endodermal phenotype, whereas at higher concentrations it induces differentiation to neuroectoderm. In the past, many RA-­128;regulated genes have been discovered in EC and ES cells and efforts are ongoing to elucidate the exact mechanisms of RA-induced ES cell differentiation and apoptosis. In the RA-triggered differentiation process of the P19 ES cells, several proteins belonging to different families participate, some being obligatory while others, dispensable. Revealing the mechanisms behind RA-induced effects on ES cells has a bearing on understanding how cells proliferate, differentiate and undergo apoptosis that can provide greater insight into cancer biology and therapy. In addition to summarizing the reports on gene/protein targets of RA in stem cells, the signaling pathways driven by some of the specific class of proteins in the presence or absence of RA in P19 ES cell differentiation, especially to an endodermal phenotype, are the focus of this review.

Nowadays, the advances in knowledge about oncologic treatment have led to an increase in survival rate for cancer patients and, consequently, a growing concern about the adverse effects of treatment in medium and long term, in order to ensure the future quality of life. For male patients in reproductive age or younger, one of the key concerns after cancer therapy is their ability to father children, since anticancer drugs exert cytotoxic effects on germ cells. Considering the incidence of cancer in children and adolescents and the vulnerability of these developmental phases to chemical injuries, this review is an attempt to highlight the importance of juvenile experimental models to test new anticancer drugs and agents with protective action. There is a relative scarcity of studies investigating the effects of chemotherapy in juvenile animals and an urgent need for further information. As far as this review was able to recover, available data about reproductive toxicology related to peripubertal treatment with anticancer drugs includes only the following pharmaceuticals: toposide, doxorrubicin, cisplatin, ciclophosphamide, cytarabine, flutamide and procarbazine. Together with the evaluation of adverse effects of anticancer drugs, is necessary to investigate possible protective agents to be pre-, co-, or post administrated with chemotherapy. Modern technologies and increasing knowledge about the cancer biology have allowed studies of new chemotherapy strategies, more effective and selective. Many of these compounds are derived from toxins and metabolites of microorganisms, plants, and animals, being a number of them isolated from marine sources, a relatively unexplored environment. Investment in research programs in bioprospecting, especially in marine environments, and pharmaceutical field, including toxicology risk evaluation, are crucial to discovery and improve new anticancer treatments.

Cyclophosphamide (CPA) remains one of the most widely prescribed anticancer drugs. It is also used in the treatment of rheumatoid arthritis, childhood nephrotic syndrome and systemic lupus erythematosus. It is a potent immunosuppressive agent. It is commonly used in blood and bone marrow transplantation. With the growing trend among women postponing childbearing, the number of women who are diagnosed with breast cancer is also increasing thus escalating the chances of exposure of the unborn child to antineoplastic drugs. A review of the literature provides strong evidence for the teratogenic effects on infants prenatally exposed to CPA. Both sporadic case reports and larger case series have demonstrated that babies with cyclophosphamide embryopathy are afflicted with intrauterine growth restriction, small for gestational age, and craniofacial malformations including eye anomalies, cleft/arched palate, hydrocephaly, micrognathia, low set microtia, hearing defects, craniosynostosis, and facial asymmetry. Also observed in these cases are limb defects such as radial, ulnar and tibial hypoplasia, club foot, digital defects of the hand and feet as well as vertebral fusion, brevicolis, and occasional Sprengel's deformity. These anomalies vary in consistency of occurrence and severity of the phenotype across cases and lack the specificity of thalidomide embryopathy or rubella embryopathy. However, they do occur is no longer in doubt. First trimester of pregnancy seems to be particularly susceptible to fetal malformations, although CPA effects on fetuses of later stages of gestation (hearing defects, growth restriction for example) are also reported occasionally. One of the major concerns from a mechanistic point of view is our inability to dissect the teratogenic effects of CPA from those of other drugs administered together with CPA as combination therapy. Animal experiments have been of particular value in that they are able to circumvent the numerous extraneous variables inherent to human case reports. They have also revealed the detrimental effects of CPA on gametes, preimplantation embryos, organogenesis as well as their potential teratogenic mechanisms. Of particular importance are the role of genetic polymorphisms, male mediated teratogenesis, ovarian failure, preimplantation embryo loss, epigenetic modifications, proxidant-antioxidant imbalance, autophagy, apoptosis, microRNAs and postclosure neural tube defects induced by CPA -all of which are areas for further research in CPA teratogenesis.

Malignant pleural mesothelioma (MPM) is a hard to treat malignancy arising from the mesothelial surface of the pleura. Immune checkpoint inhibitors are considered a promising therapeutic strategy in many hardto- treat malignancies. In this review, we are trying to provide an in depth coverage of the prognostic value of immune checkpoints aberrations as well as discuss the different novel therapeutic strategies implementing these agents in the management of MPM.

Background: 15,16-dihydrotanshinone I (DHTI), a lipophilic tanshinone extracted from Danshen root (Salvia miltiorrhiza Bunge), has been reported to function as an antitumor agent. However, its activity on osteosarcoma (OS), the most common primary malignant bone tumor, is unclear. Objective: This study aimed to determine the effects of DHTI treatment on proliferation, apoptosis and migration of human OS cell line 143B and investigate the possible underlying molecular mechanisms. Method: Human cell line 143B was used as a model for investigation of the inhibitory effects of DHTI on osteosarcoma. Cell proliferation was evaluated by MTT assays, while cell cycle progression, apoptosis and cell migration were analyzed by flow cytometer, caspase activity assays and scratch migration assays. qRT-PCR and western blot were carried out to detect the expression levels of representative genes and proteins during physiological processes examined above. Results: DHTI treatment inhibited the proliferation of 143B cells in a dose- and time-dependent manner through arresting cells in G1 phase by reducing the expression of cyclin D1, cyclin E1, CDK2, CDK4, CDK6, p-Rb, E2F1, SKP2 and increasing the expression of P53, P21cip1, P27kip1. In addition, DHTI induced apoptosis of 143B cells through caspase pathways to activate caspase-3, caspase-8, caspase-9, Bax, and PARP cleavage but reduce the expression of Bcl-2. Furthermore, DHTI treatment attenuated cell migration by down-regulating adhesion molecules VCAM-1 and ICAM-1. Conclusion: These findings suggest that DHTI could be a novel and efficient therapeutic candidate for OS treatment and further detailed investigation is warranted.

Background: A monoterpene, perillyl alcohol, has attracted attention in medicinal chemistry since it exhibited chemo-preventive and therapeutic properties against a variety of cancers. Objective: In the present work, it was aimed to obtain derivatives of perillyl alcohol through microbial biotransformation and investigate their anticancer activities against A549 and HepG2 cancer cell lines. Method: Biotransformation studies were carried out in a α-medium for 7 days at 25oC. XTT assay was performed to investigate the anticancer activities of perillyl alcohol and its biotransformation metabolite, dehydroperillic acid, against A549 and HepG2 cell lines and their selectivity using healthy cell line, NIH/3T3. Cell proliferation ELISA, BRDU (colorimetric) assay was used for measurement of proliferation in replicative cells in which DNA synthesis occurs. Flow cytometric analyses were also carried out for measuring apoptotic cell percentages, caspase 3 activation and mitochondrial membrane potential. Results: Biotransformation of perillyl alcohol with Fusarium culmorum yielded dehydroperillic acid in a yield of 20.4 %. In in vitro anticancer studies, perillyl alcohol was found to exert cytotoxicity against HepG2 cell line with an IC50 value of 409.2 μg/mL. However, this effect was not found to be selective because of its higher IC50 (250 μg/mL) value against NIH/3T3 cell line. On the other hand, dehydroperillic acid was found to be effective and also selective against A549 cell line with an IC50 value of 125 μg/mL and a selectivity index (SI) value of 400. Apoptosis inducing effects of dehydroperillic acid was better in A549 cell line. Conclusion: Dehydroperillic acid may be a good candidate for therapy of lung adenocarcinoma and may show this anticancer activity by inducing apoptosis.

Background: Polychemotherapy in ovarian cancer (OC) is the second major component of treatment. However, treatment with cytostatics is stopped in 25% of cases because of significant side effects. It is shown that concentration of certain cytokines and their balance is largely formed in accordance with a genetic polymorphism. Objective: The objective of the study was to evaluate the cytokine status of blood serum of patients with ovarian cancer with different tumor response to neoadjuvant chemotherapy (NACT). Method: Patients received 2 courses NACT according to the scheme AP. The levels of IL-1β and IL-1Ra, IL-10, TNF-α in blood serum were determined by solid phase ELISA. For molecular genetic studies we selected polymorphic variants in the promoters of the gene represented in dbS`NP NCBI and SNP500 Cancer databases. Results: The sharply declined in patients with ovarian cancer compared with the normal, level of IL-1β correlates with increased levels of IL-1RA. It is found that 75% of patients who had progression of the disease after NACT bear CT genotype of gene IL-1β associated with a low expression of the cytokine, while the TT genotype, providing a high level of the expression of IL-1β gene had met only 25% among patients in this group. At the same time 70% of patients with a complete response are the carriers of the T allele, while a complete response was associated with a higher level of IL-1β than in the progression group. Low secretion of TNF-α in all types of tumor response when testing TNF-α G-308A gene polymorphisms was associated with carriage of GA and AA genotypes, which are associated with low production of this cytokine. Increased compared to the control IL-10 production in patients with ovarian cancer associated with genotype replacement at position 1082 G/A IL-10 gene, which occured in 10% of patients with a complete response and 25% of patients with tumor progression after NACT. Conclusion: All the studied polymorphisms of IL-1β, IL-10 and TNF-α genes in patients with OC are associated with the level of these cytokines and tumor NACT response.

Background: C-glycosyl flavone, a phytochemical constituent in U.indica bulb, has been reported to possess cytotoxic activity. Objective: The present study aims to investigate the toxicity and anticancer potentials of C-glycosyl flavone against Ehrlich ascites carcinoma mice model. Method: In present study, acute and chronic toxicity along with antitumor activity of C-glycosyl flavone isolated from U.indica bulb were Performed using in vitro and in vivo methods. Acute and chronic toxicity of C-glycosyl flavone was evaluated using Swiss albino mice. The effect of C-glycosyl flavone on proliferation of Ehrlich ascites carcinoma (EAC) cells was determined. Further, growth inhibition and dissemination were studied using EAC induced mice model. Results: C-glycosyl flavone showed significant therapeutic potency against EAC cells in terms of reduced viability, cell cycle arrest, induction of apoptosis, inhibition of capillary formation, reduced VEGF levels. Moreover, there was reduction in body weight, tumor volume, viable tumor cells, increased survival of EAC induced mice upon C-glycosyl flavone treatment. Treatment also reduced dissemination of EAC cells into heart, kidney, liver and brain and diminished the pathological alterations induced by EAC cells in mice. In addition, there was an improvement in hemoglobin levels and counts of RBC, neutrophils, lymphocytes and monocytes in C-glycosyl flavone-treated mice with tumor. An enhancement of antioxidant status in C-glycosyl flavone treated EAC-bearing mice which appeared in terms of decreased serum thiobarbituric acid reactive substance and lipid peroxidation, increased GSH, SOD, Catalase and GPX. These results were comparable to a standard 5- fluorouracil treatment. C-glycosyl flavone exhibited safety profile in toxicity studies. Conclusion: Our study confirms the therapeutic potency of C-glycosyl flavone against EAC in inhibition of dissemination and growth of EAC in mice.

Background: Multiple myeloma is the second most common hematological malignancy. Interleukin-6 (IL-6) is one of the key molecules related to growth, survival and proliferation of myeloma cells. Tocilizumab is a humanized monoclonal antibody directed against receptor of IL-6. Objective: To radiolabel Tocilizumab with 99mTechnetium as a potential imaging agents for MM. Methods: IL-6R expression was studied by laser confocal microscopy in MM cell lines (U266, NCI-H929 and MM1S). Tocilizumab was derivatized with NHS-HYNIC-Tfa and radiolabeling with 99mTc. Radiochemical stability was determined. In-vitro binding and immunoreactive fraction assays were performed. Biodistribution and SPECT/CT imaging were evaluated in healthy BALB/c and MM-bearing BALB/c nude mice. Results: LCM studies allowed us to demonstrate that U266, NCI-H929 and MM1S cells present high expression of IL-6R in cell membrane. Radiolabeling was carried out in a fast, reproducible, easy and stable way having high radiochemical purity and did not interfere with epitope recognition. The immunoreactive fraction of 99mTc-HYNIC-Tocilizumab was 86.35%. Biodistribution showed a high uptake in liver, spleen, gastrointestinal tract and kidneys. SPECT/CT imaging of MM-bearing BALB/c nude mice showed liver uptake and a high tumor selective uptake at 24 hours. Conclusions: Our results support the potential role of 99mTc-HYNIC-Tocilizumb as a novel MM radiotracer for targeting IL-6 expression in-vivo. We describe the development of a formulation kit to radiolabeling monoclonal antibodies in a clinical setting. We hope that these novel molecular imaging agents will open the path to new diagnostic and therapeutic strategies for MM disease.

Background: Medulloblastoma (MB) is one of most frequent malignant tumors that affect children. Despite the relatively good survival rate, long time sequels still represent a challenge for MB. Therefore, in an attempt to reduce treatment aftereffects, new therapeutic targets are constantly being explored. Polo like kinase 1 (PLK1) is a master cell cycle regulator that is increased in proliferative cells, while its depletion has been repeatedly proposed as an oncological therapeutic strategy. Objectives: Here, we evaluated and compared the effects of PLK1 inhibition alone and in combination with currently used radio- and chemotherapy in MB cells. Methods: UW402, UW473, ONS-76 and DAOY MB cell lines were treated with BI 2536, BI 6727, GW843682X, and GSK461364 PLK1 inhibitors and cell proliferation, apoptosis, clonogenicity, cell invasion, adhesion and cell cycle distribution were evaluated. In addition, the combinatorial effect with gamma irradiation or etoposide, cisplatin and temozolomide was evaluated. Results: We show that PLK1 inhibition causes a significant decrease on cell proliferation, clonogenic capacity, cell invasion and adhesion, with modest differences between inhibitors. Yet, the four drugs cause G2/M arrest followed by increased cell death. PLK1 inhibition proved to be efficient to sensitize MB cells to radiation irrespective of the inhibitor, even though it showed thrifty results when combined with chemotherapy. Conclusions: We proved that all PLK1 inhibitors have anti-mitotic effects on MB cells, supporting the idea of using them as radiosensitizers. Taken together, our results strengthen the potential of using PLK1 as a therapeutic target to improve treatment strategy for this tumor.

Background: β lactam-structured Cox-2 inhibitors, possesses anti-proliferative and anti-inflammatory effects. Objective: In this research, the actions of a synthetic β lactam-structured Cox-2 inhibitor with 4-(4- (Methylsulfonyl) phenyl)-1-pentyl-3-phenoxyazetidin-2-one on cellular viability of cancerous lymphoblast obtained from patients with acute lymphocytic leukemia (ALL) and normal lymphocytes obtained from healthy donors were compared. Methods: % the cell viability of cancerouslymphoblasts and normal lymphocytes treated with β lactam derivatives were assayed with MTT test. Early apoptosis and necrosis were detected by double staining of annexin V/ propidium iodide and activity of caspase 3 as the final mediator in apoptotic mode of cell death was evaluated by colorimetric assay. Results: Our results showed that β lactam derivatives inhibited the proliferation of cancerous lymphoblast but not normal lymphocytes in a concentration-dependent mode by inducing apoptosis. Treatment with β lactam derivatives resulted in a rapid loss of mitochondrial trans-membrane potential and induction of reactive oxygen species (ROS) formation, and cytochrome c release in cytosol of mitochondria resulted in activation of procaspase-9 and formation of active apoptosome. Conclusion: These findings suggest that 4-(4-(Methylsulfonyl)phenyl)-1-pentyl-3-phenoxyazetidin-2-one as a β lactam could induce ROS-mediated death signaling throughmitochondrial pathway that results in apoptosis in only cancerous lymphoblast cells. The stimulationof apoptosis by β lactams may provide a pivotal mechanismfor their anticancer effect in acute lymphocytic leukemia cells.