Anti-Cancer Agents in Medicinal Chemistry (Formerly Current Medicinal Chemistry - Anti-Cancer Agents) - Volume 18, Issue 5, 2018

Malignant melanoma is a very aggressive form of skin cancer, with increasing rates every year, with an etiology that derives from the transformation and uncontrolled growth of melanocytes. There are several treatment options which can be used as unique treatment or combined, depending upon the stage of melanoma including surgical excision, chemotherapy, immunotherapy, targeted therapy. Plant Kingdom displays an unequalled potential for the synthesis of highly diversified chemical structures. Although natural compounds are synthesized in order to help the plant to interact with the environment, a large number of phytochemicals act as drugs within the human or animal body by activating various biochemical pathways. The study aims to review another approach in the management of this highly aggressive form of skin cancer, namely the effect of natural compounds in the chemoprevention of malignant melanoma.

This review highlights the multiple properties of the birch bark-derived pentacyclic triterpene betulin with special focus on its pharmacological activity in cancer and inflammation. While less well characterized compared to its hydrophilic derivative, betulinic acid, it exhibits potent anticancer activity described in many publications. Indeed, underinvestigated are its immunomodulatory functions in inflammatory diseases that appeared to enhance innate immune cell activities in an adjuvant-like fashion towards an interleukin-12 driven antitumor immunity. Herein, we like to emphasize the simultaneous and dual function of betulin on the basis of recent investigations of the tumor microenvironment and enlighten the potential use of betulin in the control of inflammation-associated carcinogenesis.

Research of steroidal compounds as anticancer agents started almost 50 years ago. During the past decades, several innovative new steroids, like cyproterone, finasteride, estramustin, exemestane and fulvestrant have successfully become a part of routine clinical practice. Meanwhile, a vast amount of new information have accumulated about the functions of the endogenous steroid system (including the characterization of enzymes, receptors, transcription pathways, etc.) and about the role of steroids in carcinogenesis. Therefore, it is regularly required to review the latest published results, focusing on a well-defined part within this research field that has definitely developed into a highly diversified speciality by now. Herein, we make an attempt to summarize the most recent results reported about anticancer agents of estrane backbone, focusing on their mechanisms of action and their structure-activity relationships. Due to the vast number and various accessibilities of scientific publications, neither other reviews nor this one can be considered as absolutely exhaustive. In spite of these restrictive factors, the current review makes a good opportunity to define the recent scientific trends in the field of estradiol-related anticancer agents.

The mushroom Ganoderma lucidum (G. lucidum) has been used for centuries in Asian countries to treat various diseases and to promote health and longevity. Clinical studies have shown beneficial effects of G. lucidum as an alternative adjuvant therapy in cancer patients without obvious toxicity. G. lucidum polysaccharides (GLP) is the main bioactive component in the water soluble extracts of this mushroom. Evidence from in vitro and in vivo studies has demonstrated that GLP possesses potential anticancer activity through immunomodulatory, anti-proliferative, pro-apoptotic, anti-metastatic and anti-angiogenic effects. Here, we briefly summarize these anticancer effects of GLP and the underlying mechanisms.

This review summarizes the literature data regarding plant lectins as novel drug sources in the prevention or treatment of cancer. Moreover, such compounds have been described as natural toxins that possess different biological activities (cytotoxic, antitumor, antimutagenic and anticarcinogenic properties). This activity depends greatly on their structure and affinity. Most of the mushroom heterosides are known as β-glucans with β-(1→3)-glycosidic bonds. It is thought that their conformation, bonds, molecular size can modulate the immune response by triggering different receptors. The mechanism on normal and tumor cells of various plant and mushroom polysaccharides and lectins is briefly presented in this paper.

Despite tremendous research efforts for effective therapies, cancer remains the plague of the century and its burden is expected to increase worldwide in the near future. Metabolic reprogramming is a firmly established hallmark of all cancers, regardless of their cellular or tissue origin, being a prerequisite for both tumor growth and invasion. Functional dependence of tumors on glycolysis and glutaminolysis and the crucial contribution of mitochondria to the tumor bioenergetic versatility are well recognized features and established therapeutic targets. The complex landscape of tumor metabolism in the context of the dynamic, bidirectional crosstalk with its stromal environment is a rapidly evolving field that increasingly supports the view of cancer both as metabolic disease and a disease of impaired cellular 'communication'. Many of the approved anticancer drugs are derived from natural sources and the search of novel drug candidates is still a priority view the rapid development of chemoresistance. Phytochemicals are biologically active plant compounds with preventive and/or curative anticancer properties able to potentiate the effects of standard therapies while decreasing their toxicity via multitarget modulatory effects. The present mini-review will briefly summarize the hallmarks of metabolic reprogramming in tumor cells and the phytochemicals that have been reported to modulate the dysregulated metabolism of tumor and its environment, with special emphasis on triterpenes.

Background: Electrochemotherapy is a novel treatment for cutaneous and subcutaneous tumors utilizing the combination of electroporation and chemotherapeutic agents. Since tumors have an increasing incidence nowadays as a result of environmental and genetic factors, electrochemotherapy could be a promising treatment for cancer patients. Objective: The aim of this article is to summarize the novel knowledge about the use of electroporation for antitumor treatments and to present a new application of electrochemotherapy with a well-known plant derived antitumor drug betulinic acid. For the review we have searched the databases of scientific and medical research to collect the available publications about the use of electrochemotherapy in the treatment of various types of cancer. Method: By the utilization of the available knowledge, we investigated the effect of electroporation on the penetration of a topically applied betulinic acid formulation into the skin by ex vivo Raman spectroscopy on hairless mouse skin. Results: Raman measurements have demonstrated that the penetration depth of betulinic acid can be remarkably ameliorated by the use of electroporation, so this protocol can be a possibility for the treatment of deeper localized cancer nodules. Furthermore, it proved the influence of various treatment times, since they caused different spatial distributions of the drug in the skin. Conclusion: The review demonstrates that electrochemotherapy is a promising tool to treat different kinds of tumors with high efficiency and with only a few moderate adverse effects. Moreover, it presents a non-invasive method to enhance the penetration of antitumor agents, which can offer novel prospects for antitumor therapies.

Background: Compounds obtained from natural resources have become important candidates in the discovery and development of drugs. Over the past few decades, marine resources have gradually attracted a large amount of attention from researchers, and many compounds with varying structures and activities have been derived from various marine resources. Since the ocean experiences more variable temperatures, lower oxygen levels and less light than the terrestrial environment, marine resources offer a substantial number of organisms that are not available or rarely detected on land. Description: Researchers expect that they can discover agents from marine organisms that exhibit good activity for diseases. Of the marine compounds acquired, the majority have shown to have good antitumor activity, and range in phases from clinical trials up to being used in the clinic. These natural products operate through different pathways and have unique antitumor effects that include inducing cell apoptosis, inhibiting cell proliferation and influencing cell migration. A variety of drugs have been used for cancer treatment during the last few years, but it has not been possible to greatly extend the survival time of advanced cancer patients. In addition, researchers are actively looking for compounds to overcome problems that include a lack of effective drugs to control the transfer of cancer cells and the development of drug-resistant microbes. Conclusion: Here, we summarize the marine natural products that have been obtained over the past few years, and analyze their antitumor effects and mechanisms. Our research will provide a significant basis for anticancer drug screening and development.

Background: Colon cancer is one of the most widespread disease, the mortality rate is high due to cancer metastasis and the development of drug resistance. In this regards, new chemotherapeutic agents with specific mechanisms of action and significant effect on patient's survival are the new era for the colon cancer drug development. Objective: The main objective of present study was to design, synthesize of a novel series of 1,3,4-thiadiazole derivatives (VR1 to VR35) and screen them against HT-29 human colon cancer cell line. Method: Newly 1,3,4-thiadiazole scaffold were designed, synthesized and further, characterized by FTIR, NMR (1H and 13C), MS and elemental analyses. Before the synthesis, molecular dynamic simulation and ADME studies were performed to find out the most potent lead compounds. Later, SRB assay using HT-29 cells and ELISA assays were performed to explore activity and molecular targets of VR24 and VR27 and find out whether in silico data had a similar pattern in the molecular level. Results: The results of docking study revealed that both VR24 and VR27 had interaction energy >-5 kcal/mol with various assigned molecular targets and the ligand-protein complexes were found to be stable with IL-6. The computational analysis of molecules showed good ADMET profiling. Later, the in vitro anticancer study was conducted where VR24 and VR27 were found to be active against HT-29 cells (GI50<10 μM). Finally, ELISA assays revealed that both the compounds had higher inhibition properties to various biomarker of colon cancer like IL-6 and COX-2. Conclusion: Collectively, these result suggested that VR24 and VR27 inhibited the assigned molecular targets, imparting their ameliorative effects against colon cancer. Due to these encouraging results, we concluded that both VR24 and VR27 may be effective against colon cancer therapy in future.

Abstract: Background: After the discovery of cisplatin, first non platinum anticancer drugs having excellent efficacy were budotitane and TiCl2(cp)2 but action mechanism is not clear. Therefore, we hereby reporting synthesis and biological activities novel titanium complexes to explore their mode of action. Objectives: Synthesis, spectral characterization, antibacterial and anticancer activity of some titanium complexes. Antibacterial studies on various bacterial strains and anticancer studies on HeLa, C6, CHO cancerous cell lines have been performed. Further, the cell death mechanistic study was done on CHO cell lines. Method: Titanium complexes with and without labile groups have been synthesized by reacting of TiCl4 with nitrogen containing ligands viz. 1,2-diaminocyclohexane, 1,10-Phenanthroline, adamantylamine, 2,2'-bipyridine, 4,4'-dimethyl-2,2'-bipyridine in predetermined molar ratios. Antibacterial and anticancer studies were performed by agar well diffusion method and MTT assay respectively. Cell cycle analysis is done by using flow cytometry. Results: Complex 2 i.e TiCl2(Phen)2 showed better activity than other complexes as an antibacterial as well as anticancer agent. Phase contrast imaging indicates that observed morphological changes of cells was dose dependent. Cell death mechanistic study have shown the increase in sub G0 phase population as well as formation of blebbing and fragmentation of chromatin material which is an indicative measure of apoptosis. Conclusion: Complex 2 proved to be more effective bactericide and cytotoxic agent. Cell cycle analysis showed cell arrest in G0 phase. Apoptosis percentage was found to increase in a dose dependent manner. So, prepared titanium complexes can be put to use as an important chemotherapeutic agents.

Background: 4-Substitutedaminoquinazoline scaffolds were reported to possess potent cytotoxic and EGFR inhibitory activity such as gefitinib (Iressa), erlotinib (Tarceva) and tandutinib. Objective: Synthesis of novel 4-substitutedaminothieno[2,3-d]pyrimidine derivatives as bioisosters of 4-substitutedaminoquinazoline derivatives with potential cytotoxic and EGFR inhibitory activity. Methods: Novel 4-substitutedaminothieno[2,3-d]pyrimidine derivatives 4a-i and 5a-c were synthesized via reacting corresponding 4-chlorothieno[2,3-d]pyrimidine derivatives 3a-c with N-methylpiperazine, morpholine, N-phenylpiperazine or 1,3-propanediamine. Six compounds (2a, 4d, 4e, 5a-c) were selected by the National Cancer Institute (USA) for evaluating their cytotoxic activity using 60 different human tumor cell lines using a single dose (10-5 Molar). The rest of the synthesized compounds (2b, 2c, 3a-c, 4a-c and 4f-i) were subjected to screening against T47D breast cancer cell line using a single dose (10-5 Molar) at Pharmacology lab., Cancer biology lab., Egyptian National Institute. Moreover, compounds 2a and 4b-e were subjected to further evaluation by IC50 determination. Finally, the inhibition of epidermal growth factor receptor (EGFR) was then investigated for the most active compounds 2a and 4d. Results: Compounds 2a and 4b-e showed significant cytotoxic activity. Compound 2a was more potent than doxorubicin against lung cancer cell line A549 with IC50 = 13.40 μM and comparable activity against MCF7. Compound 4d exhibited more potent activity than Doxorubicin against prostate PC3 (IC50 = 14.13 μM) while showed comparable activity against MCF7 and T47D. Conclusion: 4-Substitutedaminothieno[2,3-d]pyrimidine is a promising backbone for the design and synthesis of potent cytotoxic leads.

Background: The blending of two pharmacophores would generate novel molecular templates that are likely to exhibit interesting biological properties. Objective: A facile, efficient and high yielding synthesis of (E)-3-(benzo[d]thiazol-2-ylamino)-2-(1-methyl-1Hindole- 3-carbonyl)-3-(methylthio) acrylonitrile derivatives and evaluation of therapeutic potential. Method: The synthesis of target molecules has been achieved by reacting 2-aminobenzothiazole and substituted 2-(1-methyl-1H-indole-3-carbonyl)-3,3-bis(methylthio)acrylonitrile in the presence of a catalytic amount of sodium hydride in THF. Structural investigations were carried using 1H NMR, 13C NMR, FT-IR, and HRMS data. Results: In vitro anti-tumor evaluation of the synthesized compounds against MCF-7 (breast carcinoma) cell line revealed that they possess good anti-tumor activities. Compounds, 4j and 4i demonstrated significant activities against breast carcinoma (GI50 14.3 and 19.5 μM respectively). Most of the synthesized compounds were also found to be excellent NO, H2O2, DPPH, and superoxide radical scavengers. Anti-diabetic and antiinflammatory evaluation also displayed moderate activity. Conclusion: Among the compounds synthesized some of the compounds possess significant anticancer, antioxidant and anti-inflammatory properties.