Development Of Drugs For Cancer Treatment Research Articles

Cycloplatinated (II) Complex Based on Isoquinoline Alkaloid Elicits Ferritinophagy-Dependent Ferroptosis in Triple-Negative Breast Cancer Cells.

The development and optimization of metal-based anticancer drugs with novel cytotoxic mechanisms have emerged as key strategies to overcome chemotherapeutic resistance and side effects. Agents that simultaneously induce ferroptosis and autophagic death have received extensive attention as potential modalities for cancer therapy. However, only a limited set of drugs or treatment modalities can synergistically induce ferroptosis and autophagic tumor cell death. In this work, we designed and synthesized four new cycloplatinated (II) complexes harboring an isoquinoline alkaloid C∧N ligand. On screening the in vitro activity of these agents, we found that Pt-3 exhibited greater selectivity of cytotoxicity, decreased resistance factors, and improved anticancer activity compared to cisplatin. Furthermore, Pt-3, which we demonstrate can initiate potent ferritinophagy-dependent ferroptosis, exhibits less toxic and better therapeutic activity than cisplatin in vivo. Our results identify Pt-3 as a promising candidate or paradigm for further drug development in cancer treatment.

Novel imidazo[1,2,4] triazole derivatives: Synthesis, fluorescence, bioactivity for SHP1

The Src homology 2 domain-containing protein tyrosine phosphatase 1 (SHP1) is a convergent node for oncogenic cell-signaling cascades. Consequently, SHP1 represents a potential target for drug development in cancer treatment. The development of efficient methods for rapidly tracing and modulating the SHP1 activity in complex biological systems is of considerable significance for advancing the integration of diagnosis and treatment of the related disease. Thus, we designed and synthesized a series of imidazo[1,2,4] triazole derivatives containing salicylic acid to explore novel scaffolds with inhibitory activities and good fluorescence properties for SHP1. The photophysical properties and inhibitory activities of these imidazo[1,2,4] triazole derivatives (5a-5y) against SHP1PTP were thoroughly studied from the theoretical simulation and experimental application aspects. The representative compound 5p exhibited remarkable fluorescence response (P: 0.002) with fluorescence quantum yield (QY) of 0.37 and inhibitory rate of 85.21 ± 5.17% against SHP1PTP at the concentration of 100 μM. Furthermore, compound 5p showed obvious aggregation caused quenching (ACQ) effect and had high selectivity for Fe3+ ions, good anti-interference and relatively low detection limit (5.55 μM). Finally, the cellular imaging test of compound 5p also exhibited good biocompatibility and certain potential biological imaging application. This study provides a potential way to develop molecules with fluorescent properties and bioactivities for SHP1.

Attenuated Salmonellablocks cancer metastasis by activating NK cells in an IFN-γ-dependent manner

Abstract Metastasis accounts for 90% of cancer related deaths and blocking of metastatic cascade has critical clinical impact. However, the clinical drug development for cancer treatment, including cancer immunotherapies, is evaluated largely depending on their ability to cause tumour shrinkage and ignores the effect on metastasis as it has proven challenging to target. Therefore, there is an urgent need for novel therapeutic strategies and agents targeting metastasis. Using an attenuated Salmonella typhimurium strain YB1 engineered by our lab, we have found a potent suppressive effect of attenuated salmonella on cancer metastasis, regardless of cancer types and genetic background, by evoking strong anti-metastatic immune response. Further study showed that suppression of cancer metastasis by attenuated Salmonella only requires the innate immune response. Among the many induced cytokines, we identified IFN-γ as an indispensable factor for inhibiting cancer metastasis. Based on CyTOF (mass cytometry or cytometry by time of flight) analysis of the innate immune responses after Salmonella treatment and antibody-mediated cell depletion, we further demonstrated that NK cells are the major factor involved in Salmonella-provoked metastasis suppression. We found that IFN-γ was mainly produced by NK cells during early Salmonella infection, and in turn, IFN-γ promoted the accumulation, activation and cytotoxicity of NK cells. The IFN-γ-dependent NK cells directly eliminated newly accumulated cancer cells in the lung to block the cancer metastasis cascade in response to the Salmonella treatment. This work was supported by Shenzhen Science and Technology Innovation Committee Basic Science Research Grant (JCYJ20170413154523577) to Dr. Jian-Dong Huang.

Abstract 2483: Attenuated Salmonella blocks cancer metastasis by activating NK cells in an IFN-γ-dependent manner

Abstract Introduction and Objectives: The recent remarkable clinical results of cancer immunotherapies, such as immune checkpoint blockade and chimeric antigen receptor T cells (CAR-T), has sparked a great deal of enthusiasm in manipulating the immune response in the fight against cancer. Bacterial cancer therapies represent an alternative approach to targeting solid tumors for evoking anti-tumor immune responses. As a facultative anaerobic pathogen that can penetrate and colonize solid tumors, Salmonella typhimurium gained lot of interest in the investigation of bacterial cancer therapies and can exert its intrinsic antitumor activity by directly inducing systemic immune responses. However, most bacterial cancer therapies, including salmonella-based cancer therapies, have mainly focused on the suppression of already established tumors rather than metastasis. Metastasis accounts for 90% of cancer related deaths and blocking of metastatic cascade has critical clinical impact. However, the clinical drug development for cancer treatment, including cancer immunotherapies, is evaluated largely depending on their ability to cause tumor shrinkage and ignores the effect on metastasis as it has proven challenging to target. Therefore, there is an urgent need for novel therapeutic strategies and agents targeting metastasis. Experimental Procedures and Outcomes: Using an attenuated Salmonella typhimurium strain YB1 engineered by our lab, we have found a potent suppressive effect of attenuated salmonella on cancer metastasis, regardless of cancer types and genetic background, by evoking strong anti-metastatic immune response. Further study showed that suppression of cancer metastasis by attenuated Salmonella only requires the innate immune response. Among the many induced cytokines, we identified IFN-γ as an indispensable factor for inhibiting cancer metastasis. Based on CyTOF (mass cytometry or cytometry by time of flight) analysis of the innate immune responses after Salmonella treatment and antibody-mediated cell depletion, we further demonstrated that NK cells are the major factor involved in Salmonella-provoked metastasis suppression. We found that IFN-γ was mainly produced by NK cells during early Salmonella infection, and in turn, IFN-γ promoted the accumulation, activation and cytotoxicity of NK cells. The IFN-γ-dependent NK cells directly eliminated newly accumulated cancer cells in the lung to block the cancer metastasis cascade in response to the Salmonella treatment. Citation Format: Li Rong, Qiubin Lin, Shuhai Lin, Guo Fu, Jiandong Huang. Attenuated Salmonella blocks cancer metastasis by activating NK cells in an IFN-γ-dependent manner [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2483.

In silico SELEX screening and statistical analysis of newly designed 5mer peptide-aptamers as Bcl-xl inhibitors using the Taguchi method

Drug development for cancer treatment is a complex process that requires special efforts. Targeting crucial proteins is the most essential purpose of drug design in cancers. Bcl-xl is an anti-apoptotic protein that binds to pro-apoptotic proteins and interrupts their signals. Pro-apoptotic Bcl-xl effectors are short BH3 sequences that form an alpha helix and bind to anti-apoptotic proteins to inhibit their activity. Computational systematic evolution of ligands by exponential enrichment (SELEX) is an exclusive approach for developing peptide aptamers as potential effectors. Here, the amino acids with a high tendency for constructing an alpha-helical structure were selected. Due to the enormous number of pentapeptides, Taguchi method was used to study a selected number of peptides. The binding affinity of the peptides to Bcl-xl was assessed using molecular docking, and after analysis of the obtained results, a final set of optimized peptides was arranged and constructed. For a better comparison, three chemical compounds with approved anti-Bcl-xl activity were selected for comparison with the top-ranked 5mer peptides. The optimized peptides showed considerable binding affinity to Bcl-xl. The molecular dynamics (MD) simulation indicated that the designed peptide (PO5) could create considerable interactions with the BH3 domain of Bcl-xl. The MM/GBSA calculations revealed that these interactions were even stronger than those created by chemical compounds. In silico SELEX is a novel approach to design and evaluate peptide-aptamers. The experimental design improves the SELEX process considerably. Finally, PO5 could be considered a potential inhibitor of Bcl-xl and a potential candidate for cancer treatment.

Non-targeted metallomics through synchrotron radiation X-ray fluorescence with machine learning for cancer screening using blood samples

Cancer is the leading cause of death in many countries. The development of new methods for early screening of cancers is highly desired. Targeted metallomics has been successfully applied in the screening of cancers through quantification of elements in the matrix, which is time consuming and requires combined techniques for the quantification due to the large elemental difference in the matrix. This work proposed a non-targeted metallomics (NTM) approach through synchrotron radiation based X-ray fluorescence (SRXRF) and machine learning algorithms (MLAs) for the screening of cancers. One hundred serum samples were collected from cancer patients who were confirmed by pathological examination with 100 matched serum samples from healthy volunteers. The serum samples were studied with SRXRF and the spectra from both groups were directly clarified through MLAs, which did not require the quantification of elements. The NTM approach through SRXRF and MLAs is fast (5s for data collection for one sample) and accurate (over 96% accuracy) for cancer screening. Besides, this approach can also identify the most affected elements in cancer samples like Ca, Zn and Ti as we found, which may shed lights on the drug development for cancer treatment. This NTM approach can also be applied through commercially available XRF instruments or ICP-TOF-MS with MLAs. It has the potential for the screening and prediction of other diseases like COVID-19 and neurodegenerative diseases in a high throughput and least invasive way.

Roles of Non-coding RNAs and Angiogenesis in Glioblastoma.

One of the significant hallmarks of cancer is angiogenesis. It has a crucial function in tumor development and metastasis. Thus, angiogenesis has become one of the most exciting targets for drug development in cancer treatment. Here we discuss the regulatory effects on angiogenesis in glioblastoma (GBM) of non-coding RNAs (ncRNAs), including long ncRNA (lncRNA), microRNA (miRNA), and circular RNA (circRNA). These ncRNAs may function in trans or cis forms and modify gene transcription by various mechanisms, including epigenetics. NcRNAs may also serve as crucial regulators of angiogenesis-inducing molecules. These molecules include, metalloproteinases, cytokines, several growth factors (platelet-derived growth factor, vascular endothelial growth factor, fibroblast growth factor, hypoxia-inducible factor-1, and epidermal growth factor), phosphoinositide 3-kinase, mitogen-activated protein kinase, and transforming growth factor signaling pathways.

Birinapant Enhances Gemcitabine's Antitumor Efficacy in Triple-Negative Breast Cancer by Inducing Intrinsic Pathway-Dependent Apoptosis.

Triple-negative breast cancer (TNBC) is the most aggressive subgroup of breast cancer, and patients with TNBC have few therapeutic options. Apoptosis resistance is a hallmark of human cancer, and apoptosis regulators have been targeted for drug development for cancer treatment. One class of apoptosis regulators is the inhibitors of apoptosis proteins (IAPs). Dysregulated IAP expression has been reported in many cancers, including breast cancer, and has been shown to be responsible for resistance to chemotherapy. Therefore, IAPs have become attractive molecular targets for cancer treatment. Here, we first investigated the antitumor efficacy of birinapant (TL32711), a biindole-based bivalent mimetic of second mitochondria-derived activator of caspases (SMACs), in TNBC. We found that birinapant as a single agent has differential antiproliferation effects in TNBC cells. We next assessed whether birinapant has a synergistic effect with commonly used anticancer drugs, including entinostat (class I histone deacetylase inhibitor), cisplatin, paclitaxel, voxtalisib (PI3K inhibitor), dasatinib (Src inhibitor), erlotinib (EGFR inhibitor), and gemcitabine, in TNBC. Among these tested drugs, gemcitabine showed a strong synergistic effect with birinapant. Birinapant significantly enhanced the antitumor activity of gemcitabine in TNBC both in vitro and in xenograft mouse models through activation of the intrinsic apoptosis pathway via degradation of cIAP2 and XIAP, leading to apoptotic cell death. Our findings demonstrate the therapeutic potential of birinapant to enhance the antitumor efficacy of gemcitabine in TNBC by targeting the IAP family of proteins.

Targeting the stress support network regulated by autophagy and senescence for cancer treatment.

Autophagy and cellular senescence are two potent tumor suppressive mechanisms activated by various cellular stresses, including the expression of activated oncogenes. However, emerging evidence has also indicated their pro-tumorigenic activities, strengthening the case for the complexity of tumorigenesis. More specifically, tumorigenesis is a systemic process emanating from the combined accumulation of changes in the tumor support pathways, many of which cannot cause cancer on their own but might still provide excellent therapeutic targets for cancer treatment. In this review, we discuss the dual roles of autophagy and senescence during tumorigenesis, with a specific focus on the stress support networks in cancer cells modulated by these processes. A deeper understanding of such context-dependent roles may help to enhance the effectiveness of cancer therapies targeting autophagy and senescence, while limiting their potential side effects. This will steer and accelerate the pace of research and drug development for cancer treatment.

Fruticuline A, a chemically-defined diterpene, exerts antineoplastic effects in vitro and in vivo by multiple mechanisms

Natural products have been recognized as important bioactive compounds on the basis of their wide biological properties. Here we investigated the antitumor effect and molecular mechanisms of the diterpene Fruticuline A (fruti) from Salvia lachnostachys, in human cancer cell lineages and Solid Ehrlich Carcinoma in mice. Fruti reduced MCF-7 and HepG2 proliferation by the reduction of Cyclin D1 levels and decreased NF-κB gene levels in both cell types. Furthermore, fruti also induced apoptosis in HepG2 cells, reduced Bcl-2 gene expression and induced necroptosis by increasing Ripk in MCF-7 cells. In mice, fruti prevented tumor development and reduced Cyclin D1, Bcl-2 and Rela gene levels, and reduced the p-NF-κB/NF-κB ratio in tumor tissue. Furthermore, fruti induced necrosis and apoptosis, increased N-acetyl-β-D-glucosaminidase and TNF-α levels and reduced IL-10 and Vegf levels in tumor tissue. Collectively, fruti exerts antitumor effects through the inhibition of the NF-κB pathway, reducing Cyclin D1 and Bcl-2 levels. In vitro the apoptosis and necroptosis pathways are involved in the cellular death, whereas in vivo, cells undergo necrosis by increased tumor inflammation and reduction of angiogenesis. Thus, fruticuline A acts in tumor cells by multiple mechanisms and represents a promising molecule for drug development in cancer treatment.

Abstract 5032: Attenuated Salmonella blocks cancer metastasis by activating NK cells in an IFN-γ-dependent manner

Abstract Introduction and objectives: The recent remarkable clinical results of cancer immunotherapies, such as immune checkpoint blockade and chimeric antigen receptor T cells (CAR-T), has sparked a great deal of enthusiasm in manipulating the immune response in the fight against cancer. Bacterial cancer therapies represent an alternative approach to targeting solid tumours for evoking anti-tumour immune responses. As a facultative anaerobic pathogen that can penetrate and colonize solid tumours, Salmonella typhimurium gained lot of interest in the investigation of bacterial cancer therapies and can exert its intrinsic antitumor activity by directly inducing systemic immune responses. However, most bacterial cancer therapies, including salmonella-based cancer therapies, have mainly focused on the suppression of already established tumours rather than metastasis. Metastasis accounts for 90% of cancer related deaths and blocking of metastatic cascade has critical clinical impact. However, the clinical drug development for cancer treatment, including cancer immunotherapies, is evaluated largely depending on their ability to cause tumour shrinkage and ignores the effect on metastasis as it has proven challenging to target. Therefore, there is an urgent need for novel therapeutic strategies and agents targeting metastasis. Experimental procedures and outcomes Using an attenuated Salmonella typhimurium strain YB1 engineered by our lab, we have found a potent suppressive effect of attenuated salmonella on cancer metastasis, regardless of cancer types and genetic background, by evoking strong anti-metastatic immune response. Further study showed that suppression of cancer metastasis by attenuated Salmonella only requires the innate immune response. Among the many induced cytokines, we identified IFN-γ as an indispensable factor for inhibiting cancer metastasis. Based on CyTOF (mass cytometry or cytometry by time of flight) analysis of the innate immune responses after Salmonella treatment and antibody-mediated cell depletion, we further demonstrated that NK cells are the major factor involved in Salmonella-provoked metastasis suppression. We found that IFN-γ was mainly produced by NK cells during early Salmonella infection, and in turn, IFN-γ promoted the accumulation, activation and cytotoxicity of NK cells. The IFN-γ-dependent NK cells directly eliminated newly accumulated cancer cells in the lung to block the cancer metastasis cascade in response to the Salmonella treatment. Citation Format: Qiubin Lin, Li Rong, Jiandong Huang. Attenuated Salmonella blocks cancer metastasis by activating NK cells in an IFN-γ-dependent manner [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5032.

PO-016 Inhibition of cell proliferation by anti-epidermal growth factor receptor (EGFR) aptamer conjugated chitosan/siRNA nanoparticles

Introduction Gene silencing mediated by small interfering RNA (siRNA) has been widely investigated as a potential therapeutic approach. Its use, however, is hampered by its rapid degradation and poor cellular uptake into cells. Therefore, the success will depend on the design of effective systems able to selectively and efficiently deliver siRNA to target cells/organs. Our strategy relies on the use of a biocompatible biopolymer (chitosan) as carrier of siRNA coupled with specific anti-EGFR aptamers for cell targeting which is overexpressed in various cancer cells. Finally, poly (ethylene glycol) (PEG) and diethylaminoethyl (DEAE) will be covalently-linked with chitosan, in order to improve blood residency and transfection efficiency. The selected siRNA will be directed to silence receptor activator of nuclear factor-kB ligand (RANKL). Its levels are elevated in numerous cancers. Blockage of EGFR by aptamer and knockdown of RANKL by siRNA inhibit cancer cell proliferation in vitro. Material and methods Synthesise and characterise chitosan conjugates: poly (ethylene glycol) (PEG), diethylaminoethyl (DEAE), and anti-EGFR-aptamer are covalently-linked with chitosan. Synthetize, purify and characterise DEAE/PEG/anti-EGFR-aptamer-chitosan/siRNA nanoparticles Optimise the nanoformulations (adjusting polymeric and charge ratios) through tests in vitro including transfection efficacy and cell proliferation assays in different cancer cell lines. Results and discussions Nanoparticles were produced on the basis of our previous results. Particle size and zeta potential were measured by Zetasizer Nano ZS90 (Malvern Instruments Ltd., Malvern, UK). The sizes of synthesised nanoparticles were around 259±3 nm for Chitosan-DEAE15/siRNA with a zeta potential of +28.3±0.8 mV. The average cell viability of free siRNA or nanoparticle-treated cells was 89%–97% compared to nonrelated cells. The results showed that anti-EGFR-aptamer-chitosan/siRNA nanoparticles had a dose-dependent inhibition of cell proliferation. These nanoparticles had a significant inhibition effect of RANKL mRNA expression (RT-PCR assay. Conclusion Conventional cancer treatments such as chemotherapy have severe side toxicity on both tumour and host cells. Biological targeted agents such as monoclonal antibodies are available, but costly. EGFR and RANKL are two of major targets for drug development for cancer treatment. Non-viral gene therapy involved aptamer-EGFR and siRNA-RANKL is a promising therapy strategy. The supportIng grant was from MESI-Quebec (PSR-SIIRI, 2017–2020).

Immunoproteasome-selective and non-selective inhibitors: A promising approach for the treatment of multiple myeloma.

The ubiquitin-proteasome system (UPS) is the major non-lysosomal proteolytic system for the degradation of abnormal or damaged proteins no longer required. The proteasome is involved in degradation of numerous proteins which regulate the cell cycle, indicating a role in controlling cell proliferation and maintaining cell survival. Defects in the UPS can lead to anarchic cell proliferation and to tumor development. For these reasons UPS inhibition has become a significant new strategy for drug development in cancer treatment. In addition to the constitutive proteasome, which is expressed in all cells and tissues, higher organisms such as vertebrates possess two immune-type proteasomes, the thymoproteasome and the immunoproteasome. The thymoproteasome is specifically expressed by thymic cortical epithelial cells and has a role in positive selection of CD8+ T cells, whereas the immunoproteasome is predominantly expressed in monocytes and lymphocytes and is responsible for the generation of antigenic peptides for cell-mediated immunity. Recent studies demonstrated that the immunoproteasome has a preservative role during oxidative stress and is up-regulated in a number of pathological disorders including cancer, inflammatory and autoimmune diseases. As a consequence, immunoproteasome-selective inhibitors are currently the focus of anticancer drug design. At present, the commercially available proteasome inhibitors bortezomib and carfilzomib which have been validated in multiple myeloma and other model systems, appear to target both the constitutive and immunoproteasomes, indiscriminately. This lack of specificity may, in part, explain some of the side effects of these agents, such as peripheral neuropathy and gastrointestinal effects, which may be due to targeting of the constitutive proteasome in these tissues. In contrast, by selectively inhibiting the immunoproteasome, it may be possible to maintain the antimyeloma and antilymphoma efficacy while reducing these toxicities, thereby increasing the therapeutic index. This review article will be focused on the discussion of the most promising immunoproteasome specific inhibitors which have been developed in recent years. Particular attention will be devoted to the description of their mechanism of action, their structure-activity relationship, and their potential application in therapy.

Abstract 4531: Systems pharmacology to predict cellular biomarkers and optimize mono- and combination-therapy regimens: Focusing on immune checkpoint targets PD-1, PD-L1 and CTLA-4

Abstract Cancer immunotherapy focuses on stimulating and promoting the immune system to recognize and eliminate cancer cells, with several FDA approvals in recent years. However, identifying patients best suited for specific immune therapies, and determining optimal treatment regimens continue to be a clinical challenge. Using a molecular-detailed computational systems pharmacology model to identify cellular biomarkers and optimize regimens, we may be able to predict the efficacy of regimens in specific patient populations, and expedite drug development for cancer treatment. We developed a cell/receptor-based multi-compartment systems pharmacology model focusing on the immune response against a growing tumor, with the intent to test the effects of immune checkpoint inhibitors against PD-1, PD-L1 and CTLA-4 administered as mono- and combination therapies. Additionally, the model also allows for testing of other immuno-therapies, such as adoptive cell therapies, which can be combined with the checkpoint inhibitors. The model was designed and developed using the SimBiology plug-in in MATLAB. Simulations were performed with parameters that define the immune response at particular tumor stages of melanoma and NSCLC. All results were qualitatively and quantitatively compared to experimental pre-clinical and clinical data for model validation, or used for the generation of predictions suitable for further experimental testing. In silico, we have identified that administrations of the prescribed doses of 1-10 mg/kg of anti-CLTA-4 (based on binding kinetics) effectively saturates the receptors on the T cells, and promotes both an extended life span of the antigen presenting cells (APCs), and the maximum attainable activation levels of the effector T cells. The model further predicts that the effectiveness of anti-CTLA-4 therapy is limited by the immunogenicity of the system (i.e., the antigen intensity level and number of APCs presenting the antigens) in a monotonic fashion. Furthermore, injecting activated APCs without therapy would show a temporary tumor response and a subsequent recovery by the tumor to its original growth trajectory, while raising the antigen intensity had a sustained effect on tumor response. Other simulations indicate that, despite the lack of apparent tumor response, a sustained immune attack may be ongoing in the body; however, the immune activity is proportionally limited by the tumor and regulatory cells. Lastly, several dose-responses and clinical trials were simulated for both combination and monotherapies, and correlated with published clinical trial data. Future work will focus on uncovering the cellular biomarkers responsible for such results, experimentally validating them, as well as simulating optimal combination treatment regimens for future evaluation. Citation Format: Oleg Milberg, Chang Gong, Bing Wang, Paolo Vicini, Rajesh Narwal, Lorin Roskos, Aleksander Popel. Systems pharmacology to predict cellular biomarkers and optimize mono- and combination-therapy regimens: Focusing on immune checkpoint targets PD-1, PD-L1 and CTLA-4 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4531. doi:10.1158/1538-7445.AM2017-4531

In Silico Screening Identifies a Novel Potential PARP1 Inhibitor Targeting Synthetic Lethality in Cancer Treatment.

Synthetic lethality describes situations in which defects in two different genes or pathways together result in cell death. This concept has been applied to drug development for cancer treatment, as represented by Poly (ADP-ribose) polymerase (PARPs) inhibitors. In the current study, we performed a computational screening to discover new PARP inhibitors. Among the 11,247 compounds analyzed, one natural product, ZINC67913374, stood out by its superior performance in the simulation analyses. Compared with the FDA approved PARP1 inhibitor, olaparib, our results demonstrated that the ZINC67913374 compound achieved a better grid score (−86.8) and amber score (−51.42). Molecular dynamics simulations suggested that the PARP1-ZINC67913374 complex was more stable than olaparib. The binding free energy for ZINC67913374 was −177.28 kJ/mol while that of olaparib was −159.16 kJ/mol. These results indicated ZINC67913374 bound to PARP1 with a higher affinity, which suggest ZINC67913374 has promising potential for cancer drug development.

Apoptotic human neutrophil peptide-1 anti-tumor activity revealed by cellular biomechanics

Cancer remains a major cause of morbidity and mortality worldwide. Although progress has been made regarding chemotherapeutic agents, new therapies that combine increased selectivity and efficacy with low resistance are still needed. In the search for new anticancer agents, therapies based on biologically active peptides, in particular, antimicrobial peptides (AMPs), have attracted attention for their decreased resistance development and low cytotoxicity. Many AMPs have proved to be tumoricidal agents against human cancer cells, but their mode of action is still controversial. The existence of common properties shared by the membranes of bacteria and tumor cells points to similar lipid-targeting mechanisms in both cases. On the other hand, anticancer peptides (ACPs) also induce apoptosis and inhibit angiogenesis. Human neutrophil peptide-1 (HNP-1) is an endogenous AMP that has been implicated in different cellular phenomena such as tumor proliferation. The presence of HNP-1 in the serum/plasma of oncologic patients turns this peptide into a potential tumor biomarker. The present work reveals the different effects of HNP-1 on the biophysical and nanomechanical properties of solid and hematological tumor cells. Studies on cellular morphology, cellular stiffness, and membrane ultrastructure and charge using atomic force microscopy (AFM) and zeta potential measurements show a preferential binding of HNP-1 to solid tumor cells from human prostate adenocarcinoma when compared to human leukemia cells. AFM also reveals induction of apoptosis with cellular membrane defects at very low peptide concentrations. Understanding ACPs mode(s) of action will certainly open innovative pathways for drug development in cancer treatment.

Considerations when choosing oral chemotherapy: identifying and responding to patient need

IRSHAD S. & MAISEY N. (2010) European Journal of Cancer Care19, 5–11 Considerations when choosing oral chemotherapy: identifying and responding to patient need Oral chemotherapeutics are becoming increasingly accepted for the treatment of cancers and their future has never been brighter. They offer a more convenient and less invasive therapeutic option, moving cancer treatment from a predominantly hospital-based day unit into the ambulatory setting. Oral chemotherapy has the potential to maintain patient's quality of life and avoid the complications and costs of intravenous chemotherapy. It offers sustained drug exposure by providing prolonged therapy compared with intermittent IV exposure and lends itself more easily to the delivery of combination therapy. In this article we highlight the expansion of oral chemotherapeutic drug development in cancer treatment and the challenges posed by this change in treatment delivery.

Regrowth Concentration Zero (RC0) as Complementary Endpoint Parameter to Evaluate Compound Candidates During Preclinical Drug Development for Cancer Treatment

The screening process for potential anticancer drugs involves expensive and time consuming preclinical and clinical trials (CT) before a drug is approved for clinical use (CU). At present, there is a “bottleneck” at the CT/CU transition because many drugs that showed promising results during preclinical research did not pass clinical trials. We speculated that the endpoint parameters (the inhibitory concentration 50 (IC50) or lethal concentration 100 (CL100)) commonly used in proliferation assays for short-term periods (24-72 h) are not useful to predict the antiproliferative effect in vivo, especially during clinical trials. We propose the use of a parameter, regrowth concentration 0 (RC0), which will define the concentration and time necessary to kill 100 % of the cells and prevent regrowth when drug is removed. The RC0 might introduce a new bottleneck at the preclinical stage, “preclinical bottleneck”, that will select for drugs with more chances to pass clinical trials and improve the success rate of anticancer screening programs. Our proposal is supported by experiments done with the DBTRG-05MG human glioma cell lines exposed to short and long-term incubation with three different DNA replication inhibitors (aphidicolin, hydroxyurea and etoposide) and retrospective analysis of clinical trials for these drugs.

Cytoprotection and Immunomodulation in Cancer Therapy

Bioprospecting and natural products drug development for cancer treatment has become an important area. Most of the cancer chemotherapeutic agents are associated with toxicity towards normal cells and tissues. Optimal dosing of cancer chemotherapeutic agents is often limited because of severe non-myelosuppressive and myelosuppressive toxicities. It is a continuing challenge to design therapy that is safer, effective and selective. Cytoprotective agents offer opportunities to reduce treatment related toxicity of anticancer therapy without diminution of efficacy. None of the available agents satisfy criteria for an ideal cytoprotection. This has stimulated research for discovering natural resources with immunomodulatory and cytoprotective activities. This article describes chemical agents presently employed in clinical practice and reviews ethnopharmacological agents reported to have chemoprotective, radioprotective, immunomodulating, adaptogenic and antitumour activities.

Proteasome inhibitors as therapeutic agents: current and future strategies.

In cells, protein degradation is a key pathway for the destruction of abnormal or damaged proteins as well as for the elimination of proteins whose presence is no longer required. Among the various cell proteases, the proteasome, a multicatalytic macromolecular complex, is specifically required for the degradation of ubiquitinated proteins. In normal cells, the proteasome ensures the elimination of numerous proteins that play critical roles in cell functions throughout the cell cycle. Defects in the activity of this proteolytic machinery can lead to the disorders of cell function that is believed to be the root cause of certain diseases. Indeed, many proteins involved in the control of cell cycle transitions are readily destroyed by the proteasome once their tasks have been accomplished. Moreover, because proteasome inhibitors can provoke cell death, it has been suggested that proteasomes must be continually degrading certain apoptotic factors. For these reasons, proteasome inhibition has become a new and potentially significant strategy for the drug development in cancer treatment. The proteasome possesses three major peptidase activities that can individually be targeted by drugs. Different classes of proteasome inhibitors are reviewed here. In addition, we present new pseudopeptides with the enriched nitrogen backbones bearing a side chain and a modified C-terminal position that inhibit proteasome activity.