Targeted agents: the rules of combination

Advancements in Research and Treatment Applications of Patient-Derived Tumor Organoids in Colorectal Cancer

Colorectal cancer (CRC) remains a significant health burden globally, being the second leading cause of cancer-related mortality. Despite significant therapeutic advancements, resistance to systemic antineoplastic agents remains an important obstacle, highlighting the need for innovative screening tools to tailor patient-specific treatment. This review explores the application of patient-derived tumor organoids (PDTOs), three-dimensional, self-organizing models derived from patient tumor samples, as screening tools for drug resistance in CRC. PDTOs offer unique advantages over traditional models by recapitulating the tumor architecture, cellular heterogeneity, and genomic landscape and are a valuable ex vivo predictive drug screening tool. This review provides an overview of the current literature surrounding the use of PDTOs as an instrument for predicting therapy responses in CRC. We also explore more complex models, such as co-cultures with important stromal cells, such as cancer-associated fibroblasts, and organ-on-a-chip models. Furthermore, we discuss the use of PDTOs for drug repurposing, offering a new approach to identify the existing drugs effective against drug-resistant CRC. Additionally, we explore how PDTOs serve as models to gain insights into drug resistance mechanisms, using newer techniques, such as single-cell RNA sequencing and CRISPR-Cas9 genome editing. Through this review, we aim to highlight the potential of PDTOs in advancing our understanding of predicting therapy responses, drug resistance, and biomarker identification in CRC management.

Minocycline and photodynamic priming significantly improve chemotherapy efficacy in heterotypic spheroids of pancreatic ductal adenocarcinoma

The prognosis for patients with advanced-stage pancreatic ductal adenocarcinoma (PDAC) remains dismal. It is generally accepted that combination cancer therapies offer the most promise, such as Folforinox, despite their associated high toxicity. This study addresses the issue of chemoresistance by introducing a complementary dual priming approach to attenuate the DNA repair mechanism and to improve the efficacy of a type 1 topoisomerase (Top1) inhibitor. The result is a regimen that integrates drug-repurposing and nanotechnology using 3 clinically relevant FDA-approved agents (1) Top1 inhibitor (irinotecan) at subcytotoxic doses (2) benzoporphyrin derivative (BPD) as a photoactive molecule for photodynamic priming (PDP) to improve the delivery of irinotecan within the cancer cell and (3) minocycline priming (MNP) to modulate DNA repair enzyme Tdp1 (tyrosyl-DNA phosphodiesterase) activity. We demonstrate in heterotypic 3D cancer models that incorporate cancer cells and pancreatic cancer-associated fibroblasts that simultaneous targeting of Tdp1 and Top1 were significantly more effective by employing MNP and photoactivatable multi-inhibitor liposomes encapsulating BPD and irinotecan compared to monotherapies or a cocktail of dual or triple-agents. These data are encouraging and warrant further work in appropriate animal models to evolve improved therapeutic regimens.

A functional personalised oncology approach against metastatic colorectal cancer in matched patient derived organoids

Globally, colorectal cancer (CRC) is the third most frequently occurring cancer. Progression on to an advanced metastatic malignancy (metCRC) is often indicative of poor prognosis, as the 5-year survival rates of patients decline rapidly. Despite the availability of many systemic therapies for the management of metCRC, the long-term efficacies of these regimens are often hindered by the emergence of treatment resistance due to intratumoral and intertumoral heterogeneity. Furthermore, not all systemic therapies have associated biomarkers that can accurately predict patient responses. Hence, a functional personalised oncology (FPO) approach can enable the identification of patient-specific combinatorial vulnerabilities and synergistic combinations as effective treatment strategies. To this end, we established a panel of CRC patient-derived organoids (PDOs) as clinically relevant biological systems, of which three pairs of matched metCRC PDOs were derived from the primary sites (ptCRC) and metastatic lesions (mCRC). Histological and genomic characterisation of these PDOs demonstrated the preservation of histopathological and genetic features found in the parental tumours. Subsequent application of the phenotypic-analytical drug combination interrogation platform, Quadratic Phenotypic Optimisation Platform, in these pairs of PDOs identified patient-specific drug sensitivity profiles to epigenetic-based combination therapies. Most notably, matched PDOs from one patient exhibited differential sensitivity patterns to the rationally designed drug combinations despite being genetically similar. These findings collectively highlight the limitations of current genomic-driven precision medicine in guiding treatment strategies for metCRC patients. Instead, it suggests that epigenomic profiling and application of FPO could complement the identification of novel combinatorial vulnerabilities to target synchronous ptCRC and mCRC.

Dual-targeting compounds possessing enhanced anticancer activity via microtubule disruption and histone deacetylase inhibition

Dual-targeting anticancer agents 4-29 are designed by combining the structural features of purine-type microtubule-disrupting compounds and HDAC inhibitors. A library of the conjugate compounds connected by appropriate linkers was synthesized and found to possess HDACs inhibitory activity and render microtubule fragmentation by activating katanin, a microtubule-severing protein. Among various zinc-binding groups, hydroxamic acid shows the highest inhibitory activity of Class I HDACs, which was also reconfirmed by three-dimensional quantitative structure-activity relationship (3D-QSAR) pharmacophore prediction. The purine-hydroxamate conjugates exhibit enhanced cytotoxicity against MDA-MB231 breast cancer cells, H1975 lung cancer cells, and various clinical isolated non-small-cell lung cancer cells with different epidermal growth factor receptor (EGFR) status. Pyridyl substituents could be used to replace the C2 and N9 phenyl moieties in the purine-type scaffold, which can help to improve the solubility under physiological conditions, thus increasing cytotoxicity. In mice treated with the purine-hydroxamate conjugates, the tumor growth rate was significantly reduced without causing toxic effects. Our study demonstrates the potential of the dual-targeting purine-hydroxamate compounds for cancer monotherapy.

Therapeutic targeting of nuclear export and import receptors in cancer and their potential in combination chemotherapy

Systemic modalities are crucial in the management of disseminated malignancies and liquid tumours. However, patient responses and tolerability to treatment are generally poor and those that enter remission often return with refractory disease. Combination therapies provide a methodology to overcome chemoresistance mechanisms and address dose-limiting toxicities. A deeper understanding of tumorigenic processes at the molecular level has brought a targeted therapy approach to the forefront of cancer research, and novel cancer biomarkers are being identified at a rapid rate, with some showing potential therapeutic benefits. The Karyopherin superfamily of proteins is soluble receptors that mediate nucleocytoplasmic shuttling of proteins and RNAs, and recently, nuclear transport receptors have been recognized as novel anticancer targets. Inhibitors against nuclear export have been approved for clinical use against certain cancer types, whereas inhibitors against nuclear import are in preclinical stages of investigation. Mechanistically, targeting nucleocytoplasmic shuttling has shown to abrogate oncogenic signalling and restore tumour suppressor functions through nuclear sequestration of relevant proteins and mRNAs. Hence, nuclear transport inhibitors display broad spectrum anticancer activity and harbour potential to engage in synergistic interactions with a wide array of cytotoxic agents and other targeted agents. This review is focussed on the most researched nuclear transport receptors in the context of cancer, XPO1 and KPNB1, and highlights how inhibitors targeting these receptors can enhance the therapeutic efficacy of standard of care therapies and novel targeted agents in a combination therapy approach. Furthermore, an updated review on the therapeutic targeting of lesser characterized karyopherin proteins is provided and resistance to clinically approved nuclear export inhibitors is discussed.

Drug combinations screening using a Bayesian ranking approach based on dose-response models

Drug combinations have been of increasing interest in recent years for the treatment of complex diseases such as cancer, as they could reduce the risk of drug resistance. Moreover, in oncology, combining drugs may allow tackling tumor heterogeneity. Identifying potent combinations can be an arduous task since exploring the full dose-response matrix of candidate combinations over a large number of drugs is costly and sometimes unfeasible, as the quantity of available biological material is limited and may vary across patients. Our objective was to develop a rank-based screening approach for drug combinations in the setting of limited biological resources. A hierarchical Bayesian 4-parameter log-logistic (4PLL) model was used to estimate dose-response curves of dose-candidate combinations based on a parsimonious experimental design. We computed various activity ranking metrics, such as the area under the dose-response curve and Bliss synergy score, and we used the posterior distributions of ranks and the surface under the cumulative ranking curve to obtain a comprehensive final ranking of combinations. Based on simulations, our proposed method achieved good operating characteristics to identifying the most promising treatments in various scenarios with limited sample sizes and interpatient variability. We illustrate the proposed approach on real data from a combination screening experiment in acute myeloid leukemia.

CancerOmicsNet: a multi-omics network-based approach to anti-cancer drug profiling

Development of novel anti-cancer treatments requires not only a comprehensive knowledge of cancer processes and drug mechanisms of action, but also the ability to accurately predict the response of various cancer cell lines to therapeutics. Numerous computational methods have been developed to address this issue, including algorithms employing supervised machine learning. Nonetheless, high prediction accuracies reported for many of these techniques may result from a significant overlap among training, validation, and testing sets, making existing predictors inapplicable to new data. To address these issues, we developed CancerOmicsNet, a graph neural network with sophisticated attention propagation mechanisms to predict the therapeutic effects of kinase inhibitors across various tumors. Emphasizing on the system-level complexity of cancer, CancerOmicsNet integrates multiple heterogeneous data, such as biological networks, genomics, inhibitor profiling, and gene-disease associations, into a unified graph structure. The performance of CancerOmicsNet, properly cross-validated at the tissue level, is 0.83 in terms of the area under the receiver operating characteristics, which is notably higher than those measured for other approaches. CancerOmicsNet generalizes well to unseen data, i.e., it can predict therapeutic effects across a variety of cancer cell lines and inhibitors. CancerOmicsNet is freely available to the academic community at https://github.com/pulimeng/CancerOmicsNet.

Histone deacetylase (HDAC) 9: versatile biological functions and emerging roles in human cancer

BACKGROUND

HDAC9 (histone deacetylase 9) belongs to the class IIa family of histone deacetylases. This enzyme can shuttle freely between the nucleus and cytoplasm and promotes tissue-specific transcriptional regulation by interacting with histone and non-histone substrates. HDAC9 plays an essential role in diverse physiological processes including cardiac muscle development, bone formation, adipocyte differentiation and innate immunity. HDAC9 inhibition or activation is therefore a promising avenue for therapeutic intervention in several diseases. HDAC9 overexpression is also common in cancer cells, where HDAC9 alters the expression and activity of numerous relevant proteins involved in carcinogenesis.

CONCLUSIONS

This review summarizes the most recent discoveries regarding HDAC9 as a crucial regulator of specific physiological systems and, more importantly, highlights the diverse spectrum of HDAC9-mediated posttranslational modifications and their contributions to cancer pathogenesis. HDAC9 is a potential novel therapeutic target, and the restoration of aberrant expression patterns observed among HDAC9 target genes and their related signaling pathways may provide opportunities to the design of novel anticancer therapeutic strategies.

Beyond conventional immune-checkpoint inhibition - novel immunotherapies for renal cell carcinoma

The management of advanced-stage renal cell carcinoma (RCC) has been transformed by the development of immune-checkpoint inhibitors (ICIs). Nonetheless, most patients do not derive durable clinical benefit from these agents. Importantly, unlike other immunotherapy-responsive solid tumours, most RCCs have only a moderate mutational burden, and paradoxically, high levels of tumour CD8+ T cell infiltration are associated with a worse prognosis in patients with this disease. Building on the successes of antibodies targeting the PD-1 and CTLA4 immune checkpoints, multiple innovative immunotherapies are now in clinical development for the treatment of patients with RCC, including ICIs with novel targets, co-stimulatory pathway agonists, modified cytokines, metabolic pathway modulators, cell therapies and therapeutic vaccines. However, the successful development of such novel immune-based treatments and of immunotherapy-based combinations will require a disease-specific framework that incorporates a deep understanding of RCC immunobiology. In this Review, using the structure provided by the well-described cancer-immunity cycle, we outline the key steps required for a successful antitumour immune response in the context of RCC, and describe the development of promising new immunotherapies within the context of this framework. With this approach, we summarize and analyse the most encouraging targets of novel immune-based therapies within the RCC microenvironment, and review the landscape of emerging antigen-directed therapies for this disease.

Drug Combination in Cancer Treatment-From Cocktails to Conjugated Combinations

It is well recognized today that anticancer drugs often are most effective when used in combination. However, the establishment of chemotherapy as key modality in clinical oncology began with sporadic discoveries of chemicals that showed antiproliferative properties and which as a first attempt were used as single agents. In this review we describe the development of chemotherapy from its origins as a single drug treatment with cytotoxic agents to polydrug therapy that includes targeted drugs. We discuss the limitations of the first chemotherapeutic drugs as a motivation for the establishment of combined drug treatment as standard practice in spite of concerns about frequent severe, dose limiting toxicities. Next, we introduce the development of targeted treatment as a concept for advancement within the broader field of small-molecule drug combination therapy in cancer and its accelerating progress that was boosted by recent scientific and technological progresses. Finally, we describe an alternative strategy of drug combinations using drug-conjugates for selective delivery of cytotoxic drugs to tumor cells that potentiates future improvement of drug combinations in cancer treatment. Overall, in this review we outline the development of chemotherapy from a pharmacological perspective, from its early stages to modern concepts of using targeted therapies for combinational treatment.

Tumor Profiling at the Service of Cancer Therapy

Cancer treatment options have evolved significantly in the past few years. From the initial surgical procedures, to the latest next-generation technologies, we are now in the position to analyze and understand tumors in a one-by-one basis and use that to our advantage to provide with individualized treatment options that may increase patient survival. In this review, we will focus on how tumor profiling has evolved over the past decades to deliver more efficient and personalized treatment options, and how novel technologies can help us envisage the future of precision oncology toward a better management and, ultimately, increased survival.

Multitarget Anticancer Agents Based on Histone Deacetylase and Protein Kinase CK2 inhibitors

The design of multitarget drugs (MTDs) has become an innovative approach for the search of effective treatments in complex diseases such as cancer. In this work, we communicate our efforts in the design of multi-targeting histone deacetylase (HDAC) and protein kinase CK2 inhibitors as a novel therapeutic strategy against cancer. Using tetrabromobenzotriazole (TBB) and 2-dimethylamino-4,5,6,7-tetrabromo-benzimidazole (DMAT) as scaffolds for CK2 inhibition, and a hydroxamate to coordinate the zinc atom present in the active site of HDAC (zinc binding group, ZBG), new multitarget inhibitors have been designed and synthesized. According to the in vitro assays, N-Hydroxy-6-(4,5,6,7-tetrabromo-2-(dimethylamino)-1H-benzo[d]imidazol-1-yl)hexanamide (11b) is the most interesting compound, with IC₅₀ values of 0.66; 1.46 and 3.67 µM. for HDAC6; HDAC1 and CK2; respectively. Cellular assays on different cancer cell lines rendered promising results for N-Hydroxy-8-(4,5,6,7-tetrabromo-2-(dimethylamino)-1H-benzo[d]imidazol-1-yl)octanamide (11d). This inhibitor presented the highest cytotoxic activity, proapoptotic capability, and the best mitochondria-targeting and multidrug-circumventing properties, thus being the most promising drug candidate for further in vivo studies.

Systemic delivery of a Gli inhibitor via polymeric nanocarriers inhibits tumor-induced bone disease

Solid tumors frequently metastasize to bone and induce bone destruction leading to severe pain, fractures, and other skeletal-related events (SREs). Osteoclast inhibitors such as bisphosphonates delay SREs but do not prevent skeletal complications or improve overall survival. Because bisphosphonates can cause adverse side effects and are contraindicated for some patients, we sought an alternative therapy to reduce tumor-associated bone destruction. Our previous studies identified the transcription factor Gli2 as a key regulator of parathyroid hormone-related protein (PTHrP), which is produced by bone metastatic tumor cells to promote osteoclast-mediated bone destruction. In this study, we tested the treatment effect of a Gli antagonist GANT58, which inhibits Gli2 nuclear translocation and PTHrP expression in tumor cells. In initial testing, GANT58 did not have efficacy in vivo due to its low water solubility and poor bioavailability. We therefore developed a micellar nanoparticle (NP) to encapsulate and colloidally stabilize GANT58, providing a fully aqueous, intravenously injectable formulation based on the polymer poly(propylene sulfide)₁₃₅-b-poly[(oligoethylene glycol)₉ methyl ether acrylate]₁₇ (PPS₁₃₅-b-POEGA₁₇). POEGA forms the hydrophilic NP surface while PPS forms the hydrophobic NP core that sequesters GANT58. In response to reactive oxygen species (ROS), PPS becomes hydrophilic and degrades to enable drug release. In an intratibial model of breast cancer bone metastasis, treatment with GANT58-NPs decreased bone lesion area by 49% (p<.01) and lesion number by 38% (p<.05) and resulted in a 2.5-fold increase in trabecular bone volume (p<.001). Similar results were observed in intracardiac and intratibial models of breast and lung cancer bone metastasis, respectively. Importantly, GANT58-NPs reduced tumor cell proliferation but did not alter mesenchymal stem cell proliferation or osteoblast mineralization in vitro, nor was there evidence of cytotoxicity after repeated in vivo treatment. Thus, inhibition of Gli2 using GANT58-NPs is a potential therapy to reduce bone destruction that should be considered for further testing and development toward clinical translation.

Wee1 Inhibitor AZD1775 Effectively Inhibits the Malignant Phenotypes of Esophageal Squamous Cell Carcinoma In Vitro and In Vivo

Esophageal squamous cell carcinoma (ESCC) is a common malignant diagnosed cancer with increasing incidence rate and few treatment options. As a specific small-molecule inhibitor of the Wee1 tyrosine kinase, AZD1775 has previously shown potent antitumor effect on multiple types of cancer in various preclinical studies and clinical trials. However, the expression of Wee1 and the role of AZD1775 in ESCC remain unclear. In the present study, we found that the expression of Wee1 was much higher in ESCC cell lines and clinical samples than that of the corresponding controls. In addition, we demonstrated that AZD1775 exhibited strong inhibitory effect against Wee1 kinase in both tested ESCC cells at nanomolar concentrations. Moreover, AZD1775 effectively suppressed ESCC cell growth and triggered apoptosis via the mitochondrial-dependent signaling pathway. AZD1775 also diminished cell migration and invasion as well as the expression of MMP-2 and MMP-9. Interestingly, knockdown of Wee1 displayed a similar inhibitory effect of AZD1775 on ESCC cells. In addition, there was a synergism between AZD1775 and 5-fluorouracil or cisplatin in inducing cell death. More importantly, the in vivo experiments also demonstrated that AZD1775 potently inhibited ESCC cell growth and metastasis. In summary, our data suggest that the Wee1 inhibitor AZD1775 may be a potential therapeutic agent and warrants a clinical trial for patients with ESCC, even those with metastasis.

Factors Affecting Combination Trial Success (FACTS): Investigator Survey Results on Early-Phase Combination Trials

Experimental therapeutic oncology agents are often combined to circumvent tumor resistance to individual agents. However, most combination trials fail to demonstrate sufficient safety and efficacy to advance to a later phase. This study collected survey data on phase 1 combination therapy trials identified from ClinicalTrials.gov between January 1, 2003 and November 30, 2017 to assess trial design and the progress of combinations toward regulatory approval. Online surveys (N = 289, 23 questions total) were emailed to Principal Investigators (PIs) of early-phase National Cancer Institute and/or industry trials; 263 emails (91%) were received and 113 surveys completed (43%). Among phase 1 combination trials, 24.9% (95%CI: 15.3%, 34.4%) progressed to phase 2 or further; 18.7% (95%CI: 5.90%, 31.4%) progressed to phase 3 or regulatory approval; and 12.4% (95%CI: 0.00%, 25.5%) achieved regulatory approval. Observations of “clinical promise” in phase 1 combination studies were associated with higher rates of advancement past each milestone toward regulatory approval (cumulative OR = 11.9; p = 0.0002). Phase 1 combination study designs were concordant with Clinical Trial Design Task Force (CTD-TF) Recommendations 79.6% of the time (95%CI: 72.2%, 87.1%). Most discordances occurred where no plausible pharmacokinetic or pharmacodynamic interactions were expected. Investigator-defined “clinical promise” of a combination is associated with progress toward regulatory approval. Although concordance between study designs of phase 1 combination trials and CTD-TF Recommendations was relatively high, it may be beneficial to raise awareness about the best study design to use when no plausible pharmacokinetic or pharmacodynamic interactions are expected.

On the Design of Combination Cancer Therapy

Combination therapy programs are the hallmark of the successful treatment of all forms of human malignancies. In this issue of Cell, Palmer and Sorger present data suggesting that cell culture results indicative of synergistic anticancer drug interactions rarely translate clinically and that the results of combination therapies in mouse models or human clinical trials, even if successful, are best explained by the independent activities of the individually administered drugs.

Matrix Screen Identifies Synergistic Combination of PARP Inhibitors and Nicotinamide Phosphoribosyltransferase (NAMPT) Inhibitors in Ewing Sarcoma

Purpose: Although many cancers are showing remarkable responses to targeted therapies, pediatric sarcomas, including Ewing sarcoma, remain recalcitrant. To broaden the therapeutic landscape, we explored the in vitro response of Ewing sarcoma cell lines against a large collection of investigational and approved drugs to identify candidate combinations.Experimental Design: Drugs displaying activity as single agents were evaluated in combinatorial (matrix) format to identify highly active, synergistic drug combinations, and combinations were subsequently validated in multiple cell lines using various agents from each class. Comprehensive metabolomic and proteomic profiling was performed to better understand the mechanism underlying the synergy. Xenograft experiments were performed to determine efficacy and in vivo mechanism.Results: Several promising candidates emerged, including the combination of small-molecule PARP and nicotinamide phosphoribosyltransferase (NAMPT) inhibitors, a rational combination as NAMPTis block the rate-limiting enzyme in the production of nicotinamide adenine dinucleotide (NAD⁺), a necessary substrate of PARP. Mechanistic drivers of the synergistic cell killing phenotype of these combined drugs included depletion of NMN and NAD⁺, diminished PAR activity, increased DNA damage, and apoptosis. Combination PARPis and NAMPTis in vivo resulted in tumor regression, delayed disease progression, and increased survival.Conclusions: These studies highlight the potential of these drugs as a possible therapeutic option in treating patients with Ewing sarcoma. Clin Cancer Res; 23(23); 7301-11. ©2017 AACR.

In vitro nuclear magnetic resonance spectroscopy metabolic biomarkers for the combination of temozolomide with PI3K inhibition in paediatric glioblastoma cells

Recent experimental data showed that the PI3K pathway contributes to resistance to temozolomide (TMZ) in paediatric glioblastoma and that this effect is reversed by combination treatment of TMZ with a PI3K inhibitor. Our aim is to assess whether this combination results in metabolic changes that are detectable by nuclear magnetic resonance (NMR) spectroscopy, potentially providing metabolic biomarkers for PI3K inhibition and TMZ combination treatment. Using two genetically distinct paediatric glioblastoma cell lines, SF188 and KNS42, in vitro 1H-NMR analysis following treatment with the dual pan-Class I PI3K/mTOR inhibitor PI-103 resulted in a decrease in lactate and phosphocholine (PC) levels (P<0.02) relative to control. In contrast, treatment with TMZ caused an increase in glycerolphosphocholine (GPC) levels (P≤0.05). Combination of PI-103 with TMZ showed metabolic effects of both agents including a decrease in the levels of lactate and PC (P<0.02) while an increase in GPC (P<0.05). We also report a decrease in the protein expression levels of HK2, LDHA and CHKA providing likely mechanisms for the depletion of lactate and PC, respectively. Our results show that our in vitro NMR-detected changes in lactate and choline metabolites may have potential as non-invasive biomarkers for monitoring response to combination of PI3K/mTOR inhibitors with TMZ during clinical trials in children with glioblastoma, subject to further in vivo validation.

Feedback Regulation in a Cancer Stem Cell Model can Cause an Allee Effect

The exact mechanisms of spontaneous tumor remission or complete response to treatment are phenomena in oncology that are not completely understood. We use a concept from ecology, the Allee effect, to help explain tumor extinction in a model of tumor growth that incorporates feedback regulation of stem cell dynamics, which occurs in many tumor types where certain signaling molecules, such as Wnts, are upregulated. Due to feedback and the Allee effect, a tumor may become extinct spontaneously or after therapy even when the entire tumor has not been eradicated by the end of therapy. We quantify the Allee effect using an 'Allee index' that approximates the area of the basin of attraction for tumor extinction. We show that effectiveness of combination therapy in cancer treatment may occur due to the increased probability that the system will be in the Allee region after combination treatment versus monotherapy. We identify therapies that can attenuate stem cell self-renewal, alter the Allee region and increase its size. We also show that decreased response of tumor cells to growth inhibitors can reduce the size of the Allee region and increase stem cell densities, which may help to explain why this phenomenon is a hallmark of cancer.

Design and synthesis of novel dual-target agents for HDAC1 and CK2 inhibition

Drug entities able to address multiple targets can be more effective than those directed to just one biological target.

Methyl jasmonate: putative mechanisms of action on cancer cells cycle, metabolism, and apoptosis

Methyl jasmonate (MJ), an oxylipid that induces defense-related mechanisms in plants, has been shown to be active against cancer cells both in vitro and in vivo, without affecting normal cells. Here we review most of the described MJ activities in an attempt to get an integrated view and better understanding of its multifaceted modes of action. MJ (1) arrests cell cycle, inhibiting cell growth and proliferation, (2) causes cell death through the intrinsic/extrinsic proapoptotic, p53-independent apoptotic, and nonapoptotic (necrosis) pathways, (3) detaches hexokinase from the voltage-dependent anion channel, dissociating glycolytic and mitochondrial functions, decreasing the mitochondrial membrane potential, favoring cytochrome c release and ATP depletion, activating pro-apoptotic, and inactivating antiapoptotic proteins, (4) induces reactive oxygen species mediated responses, (5) stimulates MAPK-stress signaling and redifferentiation in leukemia cells, (6) inhibits overexpressed proinflammatory enzymes in cancer cells such as aldo-keto reductase 1 and 5-lipoxygenase, and (7) inhibits cell migration and shows antiangiogenic and antimetastatic activities. Finally, MJ may act as a chemosensitizer to some chemotherapics helping to overcome drug resistant. The complete lack of toxicity to normal cells and the rapidity by which MJ causes damage to cancer cells turn MJ into a promising anticancer agent that can be used alone or in combination with other agents.

Hedgehog signaling in prostate cancer and its therapeutic implication

Activation of Hedgehog (Hh) signaling is implicated in the development and progression of several tumor types, including prostate cancer, which is still the most common non-skin malignancy and the third leading cause of cancer-related mortality in men in industrialized countries worldwide. Several studies have indicated that the Hh pathway plays a crucial role in the development as well as in the progression of this disease to more aggressive and even therapy-resistant disease states. Moreover, preclinical data have shown that inhibition of Hh signaling has the potential to reduce prostate cancer invasiveness and metastatic potential. Clinical trials investigating the benefit of Hh inhibitors in patients with prostate cancer have recently been initiated. However, acquired drug resistance has already been observed in other tumor types after long-term Hh inhibition. Therefore, combining Hh inhibitors with ionizing radiation, chemotherapy or other molecular targeted agents could represent an alternative therapeutic strategy. In this review, we will highlight the role of Hh signaling in the development and progression of prostate cancer and summarize the different therapeutic applications of Hedgehog inhibition.

Development of therapeutic combinations targeting major cancer signaling pathways

Signaling networks play key homeostatic processes in living organisms but are commonly hijacked in oncogenesis. Prominent examples include genetically altered receptor tyrosine kinases and dysregulated intracellular signaling molecules. The discovery and development of targeted therapies against such oncogenic proteins has imparted clinical benefit. Nevertheless, concerns remain about the limited single-agent efficacy and narrow therapeutic indices of many of these antitumor agents. Moreover, it is apparent that oncogenic proteins comprise complex signaling networks that interact through crosstalk and feedback loops, which modify therapeutic vulnerability. These complexities mandate the study of drug combinations, which will also become necessary to reverse tumor drug resistance. Here, we outline the challenges associated with rational drug codevelopment strategies, with a focus on the importance of analytically validated biomarkers for patient selection and pharmacokinetic-pharmacodynamic (PK-PD) studies. Overall, the most informative clinical studies of novel combinations will have the following characteristics: robust scientific hypotheses leading to their selection; supportive preclinical data from contextually appropriate preclinical model systems; sufficient preclinical PK data to inform on the risk of drug-drug interactions; and detailed PD studies to determine the biologically active dose range for each agent. Toward this end, several novel clinical trial designs may be envisioned to accelerate successful drug combination development while minimizing the risk of late drug combination attrition. Although considerable challenges remain, these efforts may enable important steps to be taken toward more durable therapeutic control of many cancers.

Design and conduct of early clinical studies of two or more targeted anticancer therapies: recommendations from the task force on Methodology for the Development of Innovative Cancer Therapies

The Methodology for the Development of Innovative Cancer Therapies (MDICT) task force considered aspects of the design and conduct of early (phase I and II) studies of combinations of molecular targeted agents during their 2012 meeting. The task force defined necessary non-clinical data, such as evidence of additive or synergistic effects in multiple molecularly credentialed and validated models, and appropriate pharmacodynamic marker development. A robust hypothesis was considered critical while non-clinical pharmacokinetic studies were also considered valuable. Clinical trials should include clear objectives that will prove or disprove the hypothesis. Predictive biomarkers/classifiers should be explored in phase I studies, rather than used to select patients. Trial design should be efficient and flexible rather than based on a strict progression from phase I to II to III; researchers could consider phase I studies with an expansion cohort, Phase I/II designs or phase II studies with a safety run in. Pharmacokinetics are recommended when interactions or overlapping toxicity is expected. Pharmacodynamic evaluations should be considered especially in a subset of patients closest to the recommended dose; an attempt should be made to validate surrogate tissues to enable inclusion for all patients. Schedule and or dose should be formally explored for e.g. with a randomised or an adaptive design. Data and knowledge sharing was strongly recommended, including the creation of formal or informal consortia of laboratories with individual expertise in pathway or target based models, collaboration between companies to ensure that agents which are 'best in class' are combined, and the development of databases which will be able to inform the development of future recommendations/guidelines.

Oncology drug development and approval of systemic anticancer therapy by the U.S. Food and Drug Administration

BACKGROUND

Regulatory approval of oncology drugs is the cornerstone of the development process and approval characteristics shape eventual utilization. Approval trends and characteristics provide valuable information for drug developers and regulators and ultimately affect clinicians and patients.

METHODS

Indication characteristics were tabulated for drugs approved by the U.S. Food and Drug Administration (FDA) for systemic therapy of malignancies from 1949 through October 2011. Variables included time to approval, initial/supplemental indication, tumor type, stage of disease, specification of protein expression or genetic information, drug class, trial design, concomitant agent, trial size, and endpoint.

RESULTS

A total of 121 unique anticancer agents, including 242 unique indications, were approved. The number of trials for each indication has decreased; however, trial size has increased and more randomized controlled trials have been performed. Trial designs have increasingly used time-to-event endpoints and rarely have used symptom-based primary endpoints. Approvals have been primarily single agent, with less emphasis on palliative treatments and increasing emphasis on advanced disease stages and requirements for prior therapy. Molecular specifications in labels have increased, but they are present in less than 30% of recent indications and are not associated with shorter approval times.

CONCLUSION

Approval of oncology agents is occurring in increasingly more challenging settings, suggesting gaps between eventual practice and development in potentially suboptimal indications. Molecular specifications promise to enhance development, yet widespread use in label indications has not yet been achieved.

Synthetic lethal screening with small-molecule inhibitors provides a pathway to rational combination therapies for melanoma

Recent data show that extracellular signals are transmitted through a network of proteins rather than hierarchical signaling pathways, suggesting that the inhibition of a single component of a canonical pathway is insufficient for the treatment of cancer. The biologic outcome of signaling through a network is inherently more robust and resistant to inhibition of a single network component. In this study, we conducted a functional chemical genetic screen to identify novel interactions between signaling inhibitors that would not be predicted on the basis of our current understanding of signaling networks. We screened over 300 drug combinations in nine melanoma cell lines and have identified pairs of compounds that show synergistic cytotoxicity. The synergistic cytotoxicities identified did not correlate with the known RAS and BRAF mutational status of the melanoma cell lines. Among the most robust results was synergy between sorafenib, a multikinase inhibitor with activity against RAF, and diclofenac, a nonsteroidal anti-inflammatory drug (NSAID). Drug substitution experiments using the NSAIDs celecoxib and ibuprofen or the MAP-ERK kinase inhibitor PD325901 and the RAF inhibitor RAF265 suggest that inhibition of COX and mitogen-activated protein kinase signaling are targets for the synergistic cytotoxicity of sorafenib and diclofenac. Cotreatment with sorafenib and diclofenac interrupts a positive feedback signaling loop involving extracellular signal-regulated kinase, cellular phospholipase A2, and COX. Genome-wide expression profiling shows synergy-specific downregulation of survival-related genes. This study has uncovered novel functional drug combinations and suggests that the underlying signaling networks that control responses to targeted agents can vary substantially, depending on unexplored components of the cell genotype.

Managing drug resistance in cancer: lessons from HIV therapy

Drug resistance is a common cause of treatment failure for HIV infection and cancer. The high mutation rate of HIV leads to genetic heterogeneity among viral populations and provides the seed from which drug-resistant clones emerge in response to therapy. Similarly, most cancers are characterized by extensive genetic, epigenetic, transcriptional and cellular diversity, and drug-resistant cancer cells outgrow their non-resistant peers in a process of somatic evolution. Patient-specific combination of antiviral drugs has emerged as a powerful approach for treating drug-resistant HIV infection, using genotype-based predictions to identify the best matched combination therapy among several hundred possible combinations of HIV drugs. In this Opinion article, we argue that HIV therapy provides a 'blueprint' for designing and validating patient-specific combination therapies in cancer.

Disrupting the networks of cancer

Ecosystems are interactive systems involving communities of species and their abiotic environment. Tumors are ecosystems in which cancer cells act as invasive species interacting with native host cell species in an established microenvironment within the larger host biosphere. At its heart, to study ecology is to study interconnectedness. In ecologic science, an ecologic network is a representation of the biotic interactions in an ecosystem in which species (nodes) are connected by pairwise interactions (links). Ecologic networks and signaling network models have been used to describe and compare the structures of ecosystems. It has been shown that disruption of ecologic networks through the loss of species or disruption of interactions between them can lead to the destruction of the ecosystem. Often, the destruction of a single node or link is not enough to disrupt the entire ecosystem. The more complex the network and its interactions, the more difficult it is to cause the extinction of a species, especially without leveraging other aspects of the ecosystem. Similarly, successful treatment of cancer with a single agent is rarely enough to cure a patient without strategically modifying the support systems conducive to survival of cancer. Cancer cells and the ecologic systems they reside in can be viewed as a series of nested networks. The most effective new paradigms for treatment will be developed through application of scaled network disruption.

Potential synergies for combined targeted therapy in the treatment of neuroendocrine cancer

Well differentiated neuroendocrine tumours (WDNET) are a diverse group of cancers that are often advanced at the time of diagnosis and generally do not respond significantly to traditional chemotherapy. A number of intriguing therapeutic targets have emerged, including somatostatin receptors, insulin-like growth factor-1 (IGF-1) and its receptor (IGF-1R), the phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway, and vascular endothelial growth factor receptor. Functional somatostatin receptors and IGF-1R as well as dysregulated mTOR--a key pathway component for both growth factor signalling and protein synthesis--have been identified in human neuroendocrine tumour (NET) cell lines. Somatostatin analogues (SSA) and mTOR inhibitors have exhibited in vitro and in vivo antitumour activity against NET and have shown effects on the IGF-1 pathway in preclinical studies. SSA inhibit PI3K/Akt signalling upstream of mTOR, suggesting that the combination of an SSA and an mTOR inhibitor may have greater efficacy than either as single agents. Recent clinical trial experience has provided some encouraging findings and prompted the design of additional studies of this dual-targeted approach to treating advanced WDNET. Results of ongoing trials of dual-targeted therapy combinations will define future therapies for advanced WDNET.

Opportunities and challenges in the development of experimental drug combinations for cancer

It is becoming increasingly evident that cancers are dependent on a number of altered molecular pathways and can develop diverse mechanisms of resistance to therapy with single agents. Therefore, combination regimens may provide the best hope for effective therapies with durable effects. Despite preclinical data to support this notion, there are many challenges to the development of targeted combinations including scientific, economic, legal, and regulatory barriers. A discussion of these challenges and identification of models and best practices are presented with intent of aiding the research community in addressing real and perceived barriers to the development of combination therapies for cancer.

Temsirolimus and bevacizumab, or sunitinib, or interferon alfa and bevacizumab for patients with advanced renal cell carcinoma (TORAVA): a randomised phase 2 trial

BACKGROUND

Combining targeted treatments for renal cell carcinoma has been suggested as a possible method to improve treatment efficacy. We aimed to assess the potential synergistic or additive effect of the combination of bevacizumab, directed against the VEGF receptor, and temsirolimus, an mTOR inhibitor, in metastatic renal cell carcinoma.

METHODS

TORAVA was an open-label, multicentre randomised phase 2 study undertaken in 24 centres in France. Patients aged 18 years or older who had untreated metastatic renal cell carcinoma were randomly assigned (2:1:1) to receive the combination of bevacizumab (10 mg/kg every 2 weeks) and temsirolimus (25 mg weekly; group A), or one of the standard treatments: sunitinib (50 mg/day for 4 weeks followed by 2 weeks off; group B), or the combination of interferon alfa (9 mIU three times per week) and bevacizumab (10 mg/kg every 2 weeks; group C). Randomisation was done centrally and independently from other study procedures with computer-generated permuted blocks of four and eight patients stratified by participating centre and Eastern Cooperative Oncology Group performance status. The primary endpoint was progression-free survival (PFS) at 48 weeks (four follow-up CT scans), which was expected to be above 50% in group A. Analysis was by intention to treat. The study is ongoing for long-term overall survival. This study is registered with ClinicalTrials.gov, number NCT00619268.

FINDINGS

Between March 3, 2008 and May 6, 2009, 171 patients were randomly assigned: 88 to the experimental group (group A), 42 to group B, and 41 to group C. PFS at 48 weeks was 29.5% (26 of 88 patients, 95% CI 20.0-39.1) in group A, 35.7% (15 of 42, 21.2-50.2) in group B, and 61.0% (25 of 41, 46.0-75.9) in group C. Median PFS was 8.2 months (95% CI 7.0-9.6) in group A, 8.2 months (5.5-11.7) in group B, and 16.8 months (6.0-26.0) in group C. 45 (51%) of 88 patients in group A stopped treatment for reasons other than progression compared with five (12%) of 42 in group B and 15 (38%) of 40 in group C. Grade 3 or worse adverse events were reported in 68 (77%) of 88 patients in group A versus 25 (60%) of 42 in group B and 28 (70%) of 40 in group C. Serious adverse events were reported in 39 (44%) of 88, 13 (31%) of 42, and 18 (45%) of 40 patients in groups A, B, and C, respectively.

INTERPRETATION

The toxicity of the temsirolimus and bevacizumab combination was much higher than anticipated and limited treatment continuation over time. Clinical activity was low compared with the benefit expected from sequential use of each targeted therapy. This combination cannot be recommended for first-line treatment in patients with metastatic renal cell carcinoma.

FUNDING

French Ministry of Health and Wyeth Pharmaceuticals.

Utilizing targeted cancer therapeutic agents in combination: novel approaches and urgent requirements

The rapid development of new therapeutic agents that target specific molecular pathways involved in tumour cell proliferation provides an unprecedented opportunity to achieve a much higher degree of biochemical specificity than previously possible with traditional chemotherapeutic anticancer agents. However, the lack of specificity of these established chemotherapeutic drugs allowed a relatively straightforward approach to their use in combination therapies. Developing a paradigm for combining new, molecularly targeted agents, on the other hand, is substantially more complex. The abundance of molecular data makes it possible, at least in theory, to predict how such agents might interact across crucial growth control networks. Initial strategies to examine molecularly targeted agent combinations have produced a small number of successes in the clinic. However, for most of these combination strategies, both in preclinical models and in patients, it is not clear whether the agents being combined actually hit their targets to induce growth inhibition. Here, we consider the initial approach of the US National Cancer Institute (NCI) to the evaluation of combinations of molecularly targeted anticancer agents in patients and provide a description of several new approaches that the NCI has initiated to improve the effectiveness of combination-targeted therapy for cancer.

Personalized therapies in the cancer "omics" era

A molecular hallmark of cancer is the presence of genetic alterations in the tumoral DNA. Understanding how these alterations translate into the malignant phenotype is critical for the adequate treatment of oncologic diseases. Several cancer genome sequencing reports have uncovered the number and identity of proteins and pathways frequently altered in cancer. In this article we discuss how integration of these genomic data with other biological and proteomic studies may help in designing anticancer therapies "a la carte". An important conclusion is that next generation treatment of neoplasias must be based on rational drug combinations that target various pathways and cellular entities that sustain the survival of cancer cells.

Melanoma: a model for testing new agents in combination therapies

Treatment for both early and advanced melanoma has changed little since the introduction of interferon and IL-2 in the early 1990s. Recent data from trials testing targeted agents or immune modulators suggest the promise of new strategies to treat patients with advanced melanoma. These include a new generation of B-RAF inhibitors with greater selectivity for the mutant protein, c-Kit inhibitors, anti-angiogenesis agents, the immune modulators anti-CTLA4, anti-PD-1, and anti-CD40, and adoptive cellular therapies. The high success rate of mutant B-RAF and c-Kit inhibitors relies on the selection of patients with corresponding mutations. However, although response rates with small molecule inhibitors are high, most are not durable. Moreover, for a large subset of patients, reliable predictive biomarkers especially for immunologic modulators have not yet been identified. Progress may also depend on identifying additional molecular targets, which in turn depends upon a better understanding of the mechanisms leading to response or resistance. More challenging but equally important will be understanding how to optimize the treatment of individual patients using these active agents sequentially or in combination with each other, with other experimental treatment, or with traditional anticancer modalities such as chemotherapy, radiation, or surgery. Compared to the standard approach of developing new single agents for licensing in advanced disease, the identification and validation of patient specific and multi-modality treatments will require increased involvement by several stakeholders in designing trials aimed at identifying, even in early stages of drug development, the most effective way to use molecularly guided approaches to treat tumors as they evolve over time.

Ex vivo biomarkers: functional tools to guide targeted drug development and therapy

Most of the currently utilized predictive biomarkers for therapeutic decision-making provide information regarding the presence or absence of the drug target but reveal little about the functional circuitry of the signaling network that the drug must also impact. Ex vivo biomarkers are dynamic molecular markers evoked from living tumor cells after removal from the patient. Such ex vivo biomarkers provide valuable mechanistic information that may facilitate drug development and guide the clinical selection of targeted therapeutics.

Phase Ib study of NGR-hTNF, a selective vascular targeting agent, administered at low doses in combination with doxorubicin to patients with advanced solid tumours

Background:

Asparagine–glycine–arginine–human tumour necrosis factor (NGR–hTNF) is a vascular targeting agent exploiting a tumour-homing peptide (NGR) that selectively binds to aminopeptidase N/CD13, overexpressed on tumour blood vessels. Significant preclinical synergy was shown between low doses of NGR-TNF and doxorubicin.

Methods:

The primary aim of this phase I trial was to verify the safety of low-dose NGR–hTNF combined with doxorubicin in treating refractory/resistant solid tumours. Secondary objectives included pharmacokinetics (PKs), pharmacodynamics, and clinical activity. In all 15 patients received NGR–hTNF (0.2–0.4–0.8–1.6 μg m⁻²) and doxorubicin (60–75 mg m⁻²), both given intravenously every 3 weeks.

Results:

No dose-limiting toxicity occurred and the combination was well tolerated. Around two cases of neutropenic fevers, lasting 2 days, and two cases of cardiac ejection-fraction drops, one asymptomatic and the other symptomatic, were registered. Only 11% of the adverse events were related to NGR–hTNF and were short-lasting and mild-to-moderate in severity. There was no apparent PK interaction and the shedding of soluble TNF-receptors did not increase to 0.8 μg m⁻². One partial response (7%), at dose level 0.8 μg m⁻², and 10 stable diseases (66%), lasting for a median duration of 5.6 months, were observed.

Conclusions:

NGR–hTNF plus doxorubicin was administered safely and showed promising activity in patients pre-treated with anthracyclines. The dose level of 0.8 μg m⁻² NGR–hTNF plus doxorubicin 75 mg m⁻² was selected for phase II development.

Combination of an EGFR blocker and a COX-2 inhibitor for the treatment of advanced cutaneous squamous cell carcinoma

Cutaneous squamous cell carcinoma (SCC) is one of the most common cancers worldwide. Epidermal growth factor receptor (EGFR) is expressed at the cell surface by more than 90% of SCCs and its activation is responsible for cell cycle progression, proliferation, survival, angiogenesis and metastasis. Cyclooxygenase-2 (COX-2) is an enzyme up-regulated through EGFR signaling and responsible for some of the EGFR-dependent biological effects. An 88-year-old man presented with a recurrent, locoregionally meta-static SCC of the right parietal region, which was resistant to radiotherapy. With a combination therapy of an EGFR blocker (cetuximab) and a COX-2 inhibitor (celecoxib), the tumor regressed partially and the patient's Karnofsky index improved. We speculate that the combined use of cetuximab and COX-2 inhibitors can be a new and effective therapy for advanced and recurrent cutaneous SCCs.

Algorithmic guided screening of drug combinations of arbitrary size for activity against cancer cells

The standard treatment for most advanced cancers is multidrug therapy. Unfortunately, combinations in the clinic often do not perform as predicted. Therefore, to complement identifying rational drug combinations based on biological assumptions, we hypothesized that a functional screen of drug combinations, without limits on combination sizes, will aid the identification of effective drug cocktails. Given the myriad possible cocktails and inspired by examples of search algorithms in diverse fields outside of medicine, we developed a novel, efficient search strategy called Medicinal Algorithmic Combinatorial Screen (MACS). Such algorithms work by enriching for the fitness of cocktails, as defined by specific attributes through successive generations. Because assessment of synergy was not feasible, we developed a novel alternative fitness function based on the level of inhibition and the number of drugs. Using a WST-1 assay on the A549 cell line, through MACS, we screened 72 combinations of arbitrary size formed from a 19-drug pool across four generations. Fenretinide, suberoylanilide hydroxamic acid, and bortezomib (FSB) was the fittest. FSB performed up to 4.18 SD above the mean of a random set of cocktails or "too well" to have been found by chance, supporting the utility of the MACS strategy. Validation studies showed FSB was inhibitory in all 7 other NSCLC cell lines tested. It was also synergistic in A549, the one cell line in which this was evaluated. These results suggest that when guided by MACS, screening larger drug combinations may be feasible as a first step in combination drug discovery in a relatively small number of experiments.

Dual- and triple-acting agents for treating core and co-morbid symptoms of major depression: novel concepts, new drugs

The past decade of efforts to find improved treatment for major depression has been dominated by genome-driven programs of rational drug discovery directed toward highly selective ligands for nonmonoaminergic agents. Selective drugs may prove beneficial for specific symptoms, for certain patient subpopulations, or both. However, network analyses of the brain and its dysfunction suggest that agents with multiple and complementary modes of action are more likely to show broad-based efficacy against core and comorbid symptoms of depression. Strategies for improved multitarget exploitation of monoaminergic mechanisms include triple inhibitors of dopamine, serotonin (5-HT) and noradrenaline reuptake, and drugs interfering with feedback actions of monoamines at inhibitory 5-HT(1A), 5-HT(1B) and possibly 5-HT(5A) and 5-HT(7) receptors. Specific subsets of postsynaptic 5-HT receptors mediating antidepressant actions are under study (e.g., 5-HT(4) and 5-HT(6)). Association of a clinically characterized antidepressant mechanism with a nonmonoaminergic component of activity is an attractive strategy. For example, agomelatine (a melatonin agonist/5-HT(2C) antagonist) has clinically proven activity in major depression. Dual neurokinin(1) antagonists/5-HT reuptake inhibitors (SRIs) and melanocortin(4) antagonists/SRIs should display advantages over their selective counterparts, and histamine H(3) antagonists/SRIs, GABA(B) antagonists/SRIs, glutamatergic/SRIs, and cholinergic agents/SRIs may counter the compromised cognitive function of depression. Finally, drugs that suppress 5-HT reuptake and blunt hypothalamo-pituitary-adrenocorticotrophic axis overdrive, or that act at intracellular proteins such as GSK-3beta, may abrogate the negative effects of chronic stress on mood and neuronal integrity. This review discusses the discovery and development of dual- and triple-acting antidepressants, focusing on novel concepts and new drugs disclosed over the last 2 to 3 years.

Inhibition of breast cancer metastasis by dual liposomes to disturb complex formation

The interaction between tumour cells and blood components, mainly platelets, plays an important role in metastasis. In this study, the anti-metastatic effect of vesicles containing the cytotoxic drug perifosine (OPP) and the haemostatic inhibitor dipyridamole (DIP) was tested. These dual liposomes (DIP/OPP-L) encapsulating up to 400microg DIP/ml and 6mM OPP were prepared by extrusion technique. In vitro, DIP/OPP-L significantly inhibited the aggregation of platelets and reduced their adhesion to immobilized MT3 cells by up to 60% and 24.7%, respectively. Complex formation between platelets and tumour cells in vitro was completely prevented by DIP/OPP-vesicles. These combinatory liposomes also inhibited the metastatic capacity of circulating tumour cells by reducing the complex formation with platelets. Formation of lung and extrapulmonary metastases after intravenous administration of MT3 breast cancer cells was significantly reduced when mice were treated with a single intravenous dose of DIP/OPP-L containing 100nmol lipid 6h before tumour cell inoculation.

The evolution of fungal drug resistance: modulating the trajectory from genotype to phenotype

The emergence of drug resistance in pathogenic microorganisms provides an excellent example of microbial evolution that has had profound consequences for human health. The widespread use of antimicrobial agents in medicine and agriculture exerts strong selection for the evolution of drug resistance. Selection acts on the phenotypic consequences of resistance mutations, which are influenced by the genetic variation in particular genomes. Recent studies have revealed a mechanism by which the molecular chaperone heat shock protein 90 (Hsp90) can alter the relationship between genotype and phenotype in an environmentally contingent manner, thereby 'sculpting' the course of evolution. Harnessing Hsp90 holds great promise for treating life-threatening infectious diseases.

[Sleep and its pharmacologic treatment]

Background

The discovery of novel anticancer drugs is critical for the pharmaceutical research and development, and patient treatment. Repurposing existing drugs that may have unanticipated effects as potential candidates is one way to meet this important goal. Systematic investigation of efficient anticancer drugs could provide valuable insights into trends in the discovery of anticancer drugs, which may contribute to the systematic discovery of new anticancer drugs.

Results

In this study, we collected and analyzed 150 anticancer drugs approved by the US Food and Drug Administration (FDA). Based on drug mechanism of action, these agents are divided into two groups: 61 cytotoxic-based drugs and 89 target-based drugs. We found that in the recent years, the proportion of targeted agents tended to be increasing, and the targeted drugs tended to be delivered as signal drugs. For 89 target-based drugs, we collected 102 effect-mediating drug targets in the human genome and found that most targets located on the plasma membrane and most of them belonged to the enzyme, especially tyrosine kinase. From above 150 drugs, we built a drug-cancer network, which contained 183 nodes (150 drugs and 33 cancer types) and 248 drug-cancer associations. The network indicated that the cytotoxic drugs tended to be used to treat more cancer types than targeted drugs. From 89 targeted drugs, we built a cancer-drug-target network, which contained 214 nodes (23 cancer types, 89 drugs, and 102 targets) and 313 edges (118 drug-cancer associations and 195 drug-target associations). Starting from the network, we discovered 133 novel drug-cancer associations among 52 drugs and 16 cancer types by applying the common target-based approach. Most novel drug-cancer associations (116, 87%) are supported by at least one clinical trial study.

Conclusions

In this study, we provided a comprehensive data source, including anticancer drugs and their targets and performed a detailed analysis in term of historical tendency and networks. Its application to identify novel drug-cancer associations demonstrated that the data collected in this study is promising to serve as a fundamental for anticancer drug repurposing and development.