Dosage optimization for reducing tumor burden using a phenotype-structured population model with a drug-resistance continuum

Drug resistance is a significant obstacle to effective cancer treatment. To gain insights into how drug resistance develops, we adopted a concept called fitness landscape and employed a phenotype-structured population model by fitting to a set of experimental data on a drug used for ovarian cancer, olaparib. Our modeling approach allowed us to understand how a drug affects the fitness landscape and track the evolution of a population of cancer cells structured with a spectrum of drug resistance. We also incorporated pharmacokinetic (PK) modeling to identify the optimal dosages of the drug that could lead to long-term tumor reduction. We derived a formula that indicates that maximizing variation in plasma drug concentration over a dosing interval could be important in reducing drug resistance. Our findings suggest that it may be possible to achieve better treatment outcomes with a drug dose lower than the levels recommended by the drug label. Acknowledging the current limitations of our work, we believe that our approach, which combines modeling of both PK and drug resistance evolution, could contribute to a new direction for better designing drug treatment regimens to improve cancer treatment.

Exploring marine-derived compounds for MET signalling pathway inhibition in cancer: integrating virtual screening, ADME profiling and molecular dynamics investigations

The MET signalling pathway regulates fundamental cellular processes such as growth, division, and survival. While essential for normal cell function, dysregulation of this pathway can contribute to cancer by triggering uncontrolled proliferation and metastasis. Targeting MET activity holds promise as an effective strategy for cancer therapy. Among potential sources of anti-cancer agents, marine organisms have gained attention. In this study, we screened 47,450 natural compounds derived from marine sources within the CMNPD database against the Met crystal structure. By employing HTVS, SP, and XP docking modes, we identified three compounds (CMNPD17595, CMNPD14026, and CMNPD19696) that outperformed a reference molecule in binding affinity to the Met structure. These compounds demonstrated desirable ADME properties. Molecular Dynamics (MD) simulations for 200 ns confirmed the stability of their interactions with Met. Our findings highlight CMNPD17595, CMNPD14026, and CMNPD19696 as potential inhibitors against Met-dependent cancers. Additionally, these compounds offer new avenues for drug development, leveraging their inhibitory effects on Met to combat carcinogenesis.

Creating and screening natural product libraries

Covering: up to 2020The National Cancer Institute of the United States (NCI) has initiated a Cancer Moonshot program entitled the NCI Program for Natural Product Discovery. As part of this effort, the NCI is producing a library of 1 000 000 partially purified natural product fractions which are being plated into 384-well plates and provided to the research community free of charge. As the first 326 000 of these fractions have now been made available, this review seeks to describe the general methods used to collect organisms, extract those organisms, and create a prefractionated library. Importantly, this review also details both cell-based and cell-free bioassay methods and the adaptations necessary to those methods to productively screen natural product libraries. Finally, this review briefly describes post-screen dereplication and compound purification and scale up procedures which can efficiently identify active compounds and produce sufficient quantities of natural products for further pre-clinical development.

Design, Synthesis and Biological Evaluation of Novel 4-phenoxypyridine Derivatives Containing Semicarbazones Moiety as Potential c-Met Kinase Inhibitors

BACKGROUND

The Hepatocyte Growth Factor Receptor (HGFR) c-Met is over-expressed and/or mutated in various human tumor types. Dysregulation of c-Met/HGF signaling pathway affects cell proliferation, survival and motility, leading to tumor growth, angiogenesis, and metastasis. Therefore, c-Met has become an attractive target for cancer therapy.

OBJECTIVE

This study is aimed to evaluate a new series of 4-phenoxypyridine derivatives containing semicarbazones moiety for its cytotoxicity.

METHODS

A series of novel 4-phenoxypyridines containing semicarbazone moieties were synthesized and evaluated for their in vitro cytotoxic activities against MKN45 and A549 cancer cell lines and some selected compounds were further examined for their inhibitory activity against c-Met kinase. In order to evaluate the mechanism of cytotoxic activity of compound 24, cell cycle analysis, Annexin V/PI staining assay, AO/EB assay, wound-healing assay and docking analysis with c-Met were performed.

RESULTS

The results indicated that most of the compounds showed moderate to good antitumor activity. The compound 28 showed well cytotoxic activity against MKN45 and A549 cell lines with IC50 values of 0.25μM and 0.67μM, respectively. Compound 24 showed good activity on c-Met and its IC50 value was 0.093μM.

CONCLUSION

Their preliminary Structure-Activity Relationships (SARs) studies indicated that electronwithdrawing groups on the terminal phenyl rings are beneficial for improving the antitumor activity. Treatments of MKN45 cells with compound 24 resulted in cell cycle arrest in G2/M phase and induced apoptosis in a dose-dependent manner. In addition, AO/EB assays indicated 24 induced dose-dependent apoptosis of A549 and MKN45 cells. Wound-healing assay results indicated that compound 24 strongly inhibited A549 cell motility.

Characterization of cancer genomic heterogeneity by next-generation sequencing advances precision medicine in cancer treatment

Cancer is a heterogeneous disease with unique genomic and phenotypic features that differ between individual patients and even among individual tumor regions. In recent years, large-scale genomic studies and new next-generation sequencing technologies have uncovered more scientific details about tumor heterogeneity, with significant implications for the choice of specific molecular biomarkers and clinical decision making. Genomic heterogeneity significantly contributes to the generation of a diverse cell population during tumor development and progression, representing a determining factor for variation in tumor treatment response. It has been considered a prominent contributor to therapeutic failure, and increases the likelihood of resistance to future therapies in most common cancers. The understanding of molecular heterogeneity in cancer is a fundamental component of precision oncology, enabling the identification of genomic alteration of key genes and pathways that can be targeted therapeutically. Here, we review the emerging knowledge of tumor genomics and heterogeneity, as well as potential implications for precision medicine in cancer treatment and new therapeutic discoveries. An analysis and interpretation of the TCGA database was included.

Looking for Driver Pathways of Acquired Resistance to Targeted Therapy: Drug Resistant Subclone Generation and Sensitivity Restoring by Gene Knock-down

The past two decades have seen a shift from cytotoxic drugs to targeted therapy in medical oncology. Although targeted therapeutic agents have shown more impressive clinical efficacy and minimized adverse effects than traditional treatments, drug resistance has become the main limitation to their benefits. Several preclinical in vitro/in vivo models of acquired resistance to targeted agents in clinical practice have been developed mainly by using two strategies: i) genetic manipulation for modeling genotypes of acquired resistance, and ii) in vitro/in vivo selection of resistant models. In the present work, we propose a unifying framework, for investigating the underlying mechanisms responsible for acquired resistance to targeted therapeutic agents, starting from the generation of drug-resistant cellular subclones to the description of silencing procedures used for restoring the sensitivity to the inhibitor. This simple time- and cost-effective approach is widely applicable, and could be easily extended to investigate resistance mechanisms to other targeted therapeutic drugs in different tumor histotypes.

Living with the Effects of Cutaneous Toxicities Induced by Treatment

The introduction of targeted therapies in cancer treatment was accompanied with promising results including tumor control and patients survival benefits. However, these drugs just like their predecessors were associated with systemic side effects, including frequent and various cutaneous effects. Targeted therapies such as epidermal growth factor receptor, vascular endothelial growth factor receptor, kit, platelet-derived growth factor receptor, and BCR-ABL inhibitors as well as mammalian target of rapamycin inhibitors can induce cutaneous toxicities of varying severity. There are scarce studies on the actual impact of these toxicities on the patients' lives including the physical, social, and psychological aspects and overall quality of life. Patient's perspective in living with and beyond these toxicities remains largely uncharted but essential in optimizing care provided to those receiving treatment with targeted therapies.

Targeting cancer by binding iron: Dissecting cellular signaling pathways

Newer and more potent therapies are urgently needed to effectively treat advanced cancers that have developed resistance and metastasized. One such strategy is to target cancer cell iron metabolism, which is altered compared to normal cells and may facilitate their rapid proliferation. This is supported by studies reporting the anti-neoplastic activities of the clinically available iron chelators, desferrioxamine and deferasirox. More recently, ligands of the di-2-pyridylketone thiosemicarbazone (DpT) class have demonstrated potent and selective anti-proliferative activity across multiple cancer-types in vivo, fueling studies aimed at dissecting their molecular mechanisms of action. In the past five years alone, significant advances have been made in understanding how chelators not only modulate cellular iron metabolism, but also multiple signaling pathways implicated in tumor progression and metastasis. Herein, we discuss recent research on the targeting of iron in cancer cells, with a focus on the novel and potent DpT ligands. Several key studies have revealed that iron chelation can target the AKT, ERK, JNK, p38, STAT3, TGF-β, Wnt and autophagic pathways to subsequently inhibit cellular proliferation, the epithelial-mesenchymal transition (EMT) and metastasis. These developments emphasize that these novel therapies could be utilized clinically to effectively target cancer.

Enhancing the efficiency of bortezomib conjugated to pegylated gold nanoparticles: an in vitro study on human pancreatic cancer cells and adenocarcinoma human lung alveolar basal epithelial cells

OBJECTIVES

Gold nanoparticles have become promising vectors for cancer diagnosis and treatment. The present study investigates the effect of bortezomib (BTZ), a proteasome inhibitor, conjugated with pegylated gold nanoparticles (PEGAuNPs) in pancreatic and lung cancer cells.

METHODS

Synthesized gold nanoparticles (PEGAuNPs) were conjugated with bortezomib antitumor drug. We investigated the cytotoxicity induced by BTZ conjugated with functionalized gold nanoparticles in vitro, in the human pancreatic (S2-013) and lung (A549) cancer cell lines.

RESULTS

We found an efficient of conjugation of BTZ with PEGAuNPs. In vitro assays showed that after 72 h' incubation with PEGAuNPs-BTZ cancer cells revealed alterations in morphology; also for S2-013 and A549 cancer cells, the IC50 value of free BTZ is respectively 1.5 and 4.3 times higher than the IC50 value of PEGAuNPs-BTZ. Furthermore, for TERT-HPNE, the IC50 value is around 63 times lower for free BTZ than the conjugated nanovehicle. Cell growth inhibition results showed a remarkable enhancement in the effect of BTZ when conjugated with AuNPs.

CONCLUSIONS

Our findings showed that conjugation with PEGAuNPs enhance the BTZ growth-inhibition effect on human cancer cells (S2-013 and A549) and decreases its toxicity against normal cells (TERT-HPNE).

Pragmatic medicine in solid cancer: a translational alternative to precision medicine

The precision medicine (PM) initiative is a response to the dismal outlook in solid cancer. Despite heterogeneity, common mechanistic denominators may exist across the spectrum of solid cancer. A shift from conventional research and development (R&D) toward PM will require conceptual and structural change. As individuals and as a society, we welcome innovation, but question change. We ask: In solid cancer, does PM identify and address the causes of prior failures, and, if so, are the proposed solutions feasible? And, when may we expect safer, more effective and affordable drugs in the clinic? Considerations that prompt a pragmatic rethink include a failure analysis of translational R&D in solid cancer suggesting that trials and regulations need to be aligned with the natural history of the disease. In successful therapeutic interventions in chronic, complex disease, surrogate markers and endpoints should be consistent with the Prentice's criteria. In solid cancer, drug induced tumor shrinkage, is a drug effect and not a disease response; tumor shrinkage does not reflect nor predict interruption of the disease. Overall, we support a pragmatic, multidisciplinary, and collaborative R&D, and suggest that direction be set by clinical need and utility, and by questions, not answers. PM will prove worthwhile if it could improve clinical outcomes. The lag in therapeutics relative to diagnostics is a cause for confusion. Overdiagnosis adds to fear and harm, especially in the absence of effective interventions. A revised initiative that prioritizes metastasis research could replicate the successful HIV/AIDS model in solid cancer. A pragmatic approach may further translational efforts toward meaningfully effective, generally available, and affordable solutions.

Safe handling of oral antineoplastic medications: Focus on targeted therapeutics in the home setting

Introduction With the growing number of oral targeted therapies being approved for use in cancer therapy, the potential for long-term administration of these drugs to cancer patients is expanding. The use of these drugs in the home setting has the potential to expose family members and caregivers to them either through direct contact with the drugs or indirectly by exposure to the parent compounds and/or their active metabolites in contaminated patients' waste. Methods A systematic literature review was performed and the known adverse health effect of 32 oral targeted therapeutics is summarized. In particular, the carcinogenicity, genotoxicity, and embryo-fetal toxicity, along with the route of excretion were evaluated. Results Carcinogenicity testing has not been performed on most of the oral targeted therapeutics and the genotoxicity data are mixed. However, the majority of these drugs exhibit adverse reproductive effects, some of which are severe. Currently, available data does not permit the possibility of a health hazard from inappropriate handling of drugs and contaminated patients waste to be ignored, especially in a long-term home setting. Further research is needed to understand these issues. Conclusions With the expanding use of targeted therapies in the home setting, family members and caregivers, especially those of reproductive risk age, are, potentially at risk. Overall basic education and related precautions should be taken to protect family members and caregivers from indirect or direct exposure from these drugs. Further investigations and discussion on this subject are warranted.

Design and synthesis of a C7-aryl piperlongumine derivative with potent antimicrotubule and mutant p53-reactivating properties

Small molecules that can restore biological function to the p53 mutants found in human cancers have been highly sought to increase the anticancer efficacy. In efforts to generate hybrid anticancer drugs that can impact two or more targets simultaneously, we designed and developed piperlongumine (PL) derivatives with an aryl group inserted at the C-7 position. This insertion bestowed a combretastatin A4 (CA4, an established microtubule disruptor) like structure while retaining the piperlongumine configuration. The new compounds exhibited potent antiproliferative activities against eight cancer cell lines, in particular, were more cytotoxic against the SKBR-3 breast cancer cells which harbor a R175H mutation in p53 suppressor. KSS-9, a representative aryl PL chosen for further studies induced abundant ROS generation and protein glutathionylation. KSS-9 strongly disrupted the tubulin polymerization in vitro, destabilized the microtubules in cells and induced a potent G2/M cell cycle block. More interestingly, KSS-9 showed the ability to reactivate the p53 mutation and restore biological activity to the R175H mutant protein present in SKBR3 cells. Several procedures, including immunocytochemistry using conformation-specific antibodies for p53, immunoprecipitation combined with western blotting, electrophoretic shift mobility shift assays showed a reciprocal loss of mutant protein and generation of wild-type like protein. p53 reactivation was accompanied by the induction of the target genes, MDM2, p21cip1 and PUMA. Mechanistically, the redox-perturbation in cancer cells by the hybrid drug appears to underlie the p53 reactivation process. This anticancer drug approach merits further development.

Co-targeting AR and HSP90 suppresses prostate cancer cell growth and prevents resistance mechanisms

Persistent androgen receptor (AR) signaling in castration resistant prostate cancer (CRPC) underpins the urgent need for therapeutic strategies that better target this pathway. Combining classes of agents that target different components of AR signaling has the potential to delay resistance and improve patient outcomes. Many oncoproteins, including the AR, rely on the molecular chaperone heat shock protein 90 (Hsp90) for functional maturation and stability. In this study, enhanced anti-proliferative activity of the Hsp90 inhibitors 17-allylamino-demethoxygeldanamycin (17-AAG) and AUY922 in androgen-sensitive and CRPC cells was achieved when the agents were used in combination with AR antagonists bicalutamide or enzalutamide. Moreover, significant caspase-dependent cell death was achieved using sub-optimal agent doses that individually have no effect. Expression profiling demonstrated regulation of a broadened set of AR target genes with combined 17-AAG and bicalutamide compared with the respective single agent treatments. This enhanced inhibition of AR signaling was accompanied by impaired chromatin binding and nuclear localization of the AR. Importantly, expression of the AR variant AR-V7 that is implicated in resistance to AR antagonists was not induced by combination treatment. Likewise, the heat shock response that is typically elicited with therapeutic doses of Hsp90 inhibitors, and is a potential mediator of resistance to these agents, was significantly reduced by combination treatment. In summary, the co-targeting strategy in this study more effectively inhibits AR signaling than targeting AR or HSP90 alone and prevents induction of key resistance mechanisms in prostate cancer cells. These findings merit further evaluation of this therapeutic strategy to prevent CRPC growth.

Targeted therapy: resistance and re-sensitization

The last two decades have witnessed a paradigm shift from cytotoxic drugs to targeted therapy in medical oncology and pharmaceutical innovation. Inspired by breakthroughs in molecular and cellular biology, a number of novel synthesized chemical compounds and recombinant antibodies have been developed to selectively target oncogenic signaling pathways in a broad array of tumor types. Although targeted therapeutic agents show impressive clinical efficacy and minimized adverse effects compared with traditional treatments, the challenging drug-resistant issue has also emerged to limit their benefits to cancer patients. In this regard, we aim to improve targeted therapy by presenting a systematic framework regarding the drug resistance mechanisms and alternative approaches to re-sensitize cancer cells/tissues therapeutically.

Protecting the normal in order to better kill the cancer

Chemotherapy is the only option for oncologists when a cancer has widely spread to different body sites. However, almost all currently available chemotherapeutic drugs will eventually encounter resistance after their initial positive effect, mainly because cancer cells develop genetic alterations, collectively coined herein as mutations, to adapt to the therapy. Some patients may still respond to a second chemo drug, but few cases respond to a third one. Since it takes time for cancer cells to develop new mutations and then select those life-sustaining ones via clonal expansion, "run against time for mutations to emerge" should be a crucial principle for treatment of those currently incurable cancers. Since cancer cells constantly change to adapt to the therapy whereas normal cells are stable, it may be a better strategy to shift our focus from killing cancer cells per se to protecting normal cells from chemotherapeutic toxicity. This new strategy requires the development of new drugs that are nongenotoxic and can quickly, in just hours or days, kill cancer cells without leaving the still-alive cells with time to develop mutations, and that should have their toxicities confined to only one or few organs, so that specific protections can be developed and applied.

Mechanisms of lapatinib resistance in HER2-driven breast cancer

Targeted therapies have been approved for various malignancies but the acquisition of resistance remains a substantial challenge in the clinical management of advanced cancers. Twenty-five per cent of breast cancers overexpress ErbB2/HER2, which confers a more aggressive phenotype and is associated with a poor prognosis. HER2-targeting therapies (trastuzumab, pertuzumab, TDM1 and lapatinib) are available, but a significant fraction of HER2-positive breast cancers eventually relapse or progress. This suggests that acquired or intrinsic resistance enables escape from HER2 inhibition. This review focuses on mechanisms of intrinsic/acquired resistance to lapatinib identified in preclinical and clinical studies. A better understanding of these mechanisms could lead to novel predictive markers of lapatinib response and to novel therapeutic strategies for breast cancer patients.

An Overview on the Sequential Treatment of Pancreatic Neuroendocrine Tumors (pNETs)

Patients suffering from pancreatic neuroendocrine tumors (pNETs) are now candidates to receive novel approved drugs that have demonstrated benefit in disease control rate and delay the time taken for tumor progression in Phase III clinical trials; for example, sunitinib, everolimus and lanreotide. Though pNETs represent a rare and heterogeneous disease, recent approaches are being taken to better understand the molecular pathways involved in carcinogenesis. Consequently, new treatment strategies are now available and others still under investigation show promising results. However, some questions around how to approach patients with pNETs are still unresolved, such as what the best sequence of treatments we can offer to each of our patients in the clinic at any time of their disease would be. Therapeutic decisions are, at the moment, guided by clinical judgment, based on different parameters coming from retrospective analysis and non-randomized clinical trials. However, advances in genomic research would lead to a more precise approach using therapeutic targets that would also allow the development of new agents, prognostic or predictive biomarkers and a better understanding of resistance mechanisms. The following article is a comprehensive review of the approved and investigational drugs in pNET, and highlights the current concerns about treatment sequencing, but also provides an update of some of the present and future efforts for an improvement in the therapeutic algorithm of the disease.

Cancer modelling in the NGS era - Part I: Emerging technology and initial modelling

It is today indisputable that great progresses have been made in our molecular understanding of cancer cells, but an effective implementation of such knowledge into dramatic cancer-cures is still belated and yet desperately needed. This review gives a snapshot at where we stand today in this search for cancer understanding and definitive treatments, how far we have progressed and what are the major obstacles we will have to overcome both technologically and for disease modelling. In the first part, promising 3rd/4th Generation Sequencing Technologies will be summarized (particularly IonTorrent and OxfordNanopore technologies). Cancer modelling will be then reviewed from its origin in XIX Century Germany to today's NGS applications for cancer understanding and therapeutic interventions. Developments after Molecular Biology revolution (1953) are discussed as successions of three phases. The first, PH1, labelled "Clonal Outgrowth" (from 1960s to mid 1980s) was characterized by discoveries in cytogenetics (Nowell, Rowley) and viral oncology (Dulbecco, Bishop, Varmus), which demonstrated clonality. Treatments were consequently dominated by a "cytotoxic eradication" strategy with chemotherapeutic agents. In PH2, (from the mid 1980s to our days) the description of cancer as "Gene Networks" led to targeted-gene-therapies (TGTs). TGTs are the focus of Section 3: in view of their apparent failing (Ephemeral Therapies), alternative strategies will be discussed in review part II (particularly cancer immunotherapy, CIT). Additional Pitfalls impinge on the concepts of tumour heterogeneity (inter/intra; ITH). The described pitfalls set the basis for a new phase, PH3, which is called "NGS Era" and will be also discussed with ten emerging cancer models in the Review 2nd part.

Chemotherapy and targeted therapy in advanced biliary tract carcinoma: a pooled analysis of clinical trials

BACKGROUND

In biliary tract cancer, gemcitabine platinum (GP) doublet palliative chemotherapy is the current standard treatment. The aim of this study was to analyze recent trials, even those small and nonrandomized, and identify superior new regimens.

METHODS

Trials published in English between January 2000 and January 2014 were analyzed, as well as ASCO abstracts from 2010 to 2013.

RESULTS

In total, 161 trials comprising 6,337 patients were analyzed. The pooled results of standard therapy GP (no fluoropyrimidine, F, or other drug) were as follows: the median response rate (RR), tumor control rate (TCR), time to tumor progression (TTP) and overall survival (OS) were 25.9 and 63.5%, and 5.3 and 9.5 months, respectively. GFP triplets as well as G-based chemotherapy plus targeted therapy were significantly superior to GP concerning tumor control (TCR, TTP) and OS, with no difference in RR.

CONCLUSION

Triplet combinations of GFP as well as G-based chemotherapy with (predominantly EGFR) targeted therapy are most effective concerning tumor control and survival.

Necrosis, and then stress induced necrosis-like cell death, but not apoptosis, should be the preferred cell death mode for chemotherapy: clearance of a few misconceptions

Cell death overarches carcinogenesis and is a center of cancer researches, especially therapy studies. There have been many nomenclatures on cell death, but only three cell death modes are genuine, i.e. apoptosis, necrosis and stress-induced cell death (SICD). Like apoptosis, SICD is programmed. Like necrosis, SICD is a pathological event and may trigger regeneration and scar formation. Therefore, SICD has subtypes of stress-induced apoptosis-like cell death (SIaLCD) and stress-induced necrosis-like cell death (SInLCD). Whereas apoptosis removes redundant but healthy cells, SICD removes useful but ill or damaged cells. Many studies on cell death involve cancer tissues that resemble parasites in the host patients, which is a complicated system as it involves immune clearance of the alien cancer cells by the host. Cancer resembles an evolutionarily lower-level organism having a weaker apoptosis potential and poorer DNA repair mechanisms. Hence, targeting apoptosis for cancer therapy, i.e. killing via SIaLCD, will be less efficacious and more toxic. On the other hand, necrosis of cancer cells releases cellular debris and components to stimulate immune function, thus counteracting therapy-caused immune suppression and making necrosis better than SIaLCD for chemo drug development.