Overcoming the challenges of cancer drug resistance through bacterial-mediated therapy.

Despite tremendous efforts to fight cancer, it remains a major public health problem and a leading cause of death worldwide. With increased knowledge of cancer pathways and improved technological platforms, precision therapeutics that specifically target aberrant cancer pathways have improved patient outcomes. Nevertheless, a primary cause of unsuccessful cancer therapy remains cancer drug resistance. In this review, we summarize the broad classes of resistance to cancer therapy, particularly pharmacokinetics, the tumor microenvironment, and drug resistance mechanisms. Furthermore, we describe how bacterial-mediated cancer therapy, a bygone mode of treatment, has been revitalized by synthetic biology and is uniquely suited to address the primary resistance mechanisms that confound traditional therapies. Through genetic engineering, we discuss how bacteria can be potent anticancer agents given their tumor targeting potential, anti-tumor activity, safety, and coordinated delivery of anti-cancer drugs

Absence of \u3ci\u3esodA\u3c/i\u3e Increases the Levels of Oxidation of Key Metabolic Determinants of \u3ci\u3eBorrelia burgdorferi\u3c/i\u3e

Borrelia burgdorferi, the causative agent of Lyme disease, alters its gene expression in response to environmental signals unique to its tick vector or vertebrate hosts. B. burgdorferi carries one superoxide dismutase gene (sodA) capable of controlling intracellular superoxide levels. Previously, sodA was shown to be essential for infection of B. burgdorferi in the C3H/HeN model of Lyme disease. We employed two-dimensional electrophoresis (2-DE) and immunoblot analysis with antibodies specific to carbonylated proteins to identify targets that were differentially oxidized in the soluble fractions of the sodA mutant compared to its isogenic parental control strain following treatment with an endogenous superoxide generator, methyl viologen (MV, paraquat). HPLC-ESI-MS/MS analysis of oxidized proteins revealed that several proteins of the glycolytic pathway (BB0057, BB0020, BB0348) exhibited increased carbonylation in the sodA mutant treated with MV. Levels of ATP and NAD/NADH were reduced in the sodA mutant compared with the parental strain following treatment with MV and could be attributed to increased levels of oxidation of proteins of the glycolytic pathway. In addition, a chaperone, HtpG (BB0560), and outer surface protein A (OspA, BBA15) were also observed to be oxidized in the sodA mutant. Immunoblot analysis revealed reduced levels of Outer surface protein C (OspC), Decorin binding protein A (DbpA), fibronectin binding protein (BBK32), RpoS and BosR in the sodA mutant compared to the control strains. Viable sodA mutant spirochetes could not be recovered from both gp91/phox−⁄− and iNOS deficient mice while borrelial DNA was detected in multiple tissues samples from infected mice at significantly lower levels compared to the parental strain. Taken together, these observations indicate that the increased oxidation of select borrelial determinants and reduced levels of critical pathogenesis-associated lipoproteins contribute to the in vivo deficit of the sodA mutant in the mouse model of Lyme disease. This study, utilizing the sodA mutant, has provided insights into adaptive capabilities critical for survival of B. burgdorferi in its hosts

Transcriptomic-metabolomic reprogramming in EGFR-mutant NSCLC early adaptive drug escape linking TGFβ2-bioenergetics-mitochondrial priming.

The impact of EGFR-mutant NSCLC precision therapy is limited by acquired resistance despite initial excellent response. Classic studies of EGFR-mutant clinical resistance to precision therapy were based on tumor rebiopsies late during clinical tumor progression on therapy. Here, we characterized a novel non-mutational early adaptive drug-escape in EGFR-mutant lung tumor cells only days after therapy initiation, that is MET-independent. The drug-escape cell states were analyzed by integrated transcriptomic and metabolomics profiling uncovering a central role for autocrine TGFβ2 in mediating cellular plasticity through profound cellular adaptive Omics reprogramming, with common mechanistic link to prosurvival mitochondrial priming. Cells undergoing early adaptive drug escape are in proliferative-metabolic quiescent, with enhanced EMT-ness and stem cell signaling, exhibiting global bioenergetics suppression including reverse Warburg, and are susceptible to glutamine deprivation and TGFβ2 inhibition. Our study further supports a preemptive therapeutic targeting of bioenergetics and mitochondrial priming to impact early drug-escape emergence using EGFR precision inhibitor combined with broad BH3-mimetic to interrupt BCL-2/BCL-xL together, but not BCL-2 alone

Aurora kinase A drives the evolution of resistance to third-generation EGFR inhibitors in lung cancer.

Although targeted therapies often elicit profound initial patient responses, these effects are transient due to residual disease leading to acquired resistance. How tumors transition between drug responsiveness, tolerance and resistance, especially in the absence of preexisting subclones, remains unclear. In epidermal growth factor receptor (EGFR)-mutant lung adenocarcinoma cells, we demonstrate that residual disease and acquired resistance in response to EGFR inhibitors requires Aurora kinase A (AURKA) activity. Nongenetic resistance through the activation of AURKA by its coactivator TPX2 emerges in response to chronic EGFR inhibition where it mitigates drug-induced apoptosis. Aurora kinase inhibitors suppress this adaptive survival program, increasing the magnitude and duration of EGFR inhibitor response in preclinical models. Treatment-induced activation of AURKA is associated with resistance to EGFR inhibitors in vitro, in vivo and in most individuals with EGFR-mutant lung adenocarcinoma. These findings delineate a molecular path whereby drug resistance emerges from drug-tolerant cells and unveils a synthetic lethal strategy for enhancing responses to EGFR inhibitors by suppressing AURKA-driven residual disease and acquired resistance

Co-activation of STAT3 and YES-Associated Protein 1 (YAP1) Pathway in EGFR-Mutant NSCLC

Background: The efficacy of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in EGFR-mutant non–small cell lung cancer (NSCLC) is limited by adaptive activation of cell survival signals. We hypothesized that both signal transducer and activator of transcription 3 (STAT3) and Src-YES-associated protein 1 (YAP1) signaling are dually activated during EGFR TKI treatment to limit therapeutic response. Methods: We used MTT and clonogenic assays, immunoblotting, and quantitative polymerase chain reaction to evaluate the efficacy of EGFR TKI alone and in combination with STAT3 and Src inhibition in three EGFR-mutant NSCLC cell lines. The Chou-Talalay method was used for the quantitative determination of drug interaction. We examined tumor growth inhibition in one EGFR-mutant NSCLC xenograft model (n = 4 mice per group). STAT3 and YAP1 expression was evaluated in tumors from 119 EGFR-mutant NSCLC patients (64 in an initial cohort and 55 in a validation cohort) by quantitative polymerase chain reaction. Kaplan-Meier and Cox regression analyses were used to assess the correlation between survival and gene expression. All statistical tests were two-sided. Results: We discovered that lung cancer cells survive initial EGFR inhibitor treatment through activation of not only STAT3 but also Src-YAP1 signaling. Cotargeting EGFR, STAT3, and Src was synergistic in two EGFR-mutant NSCLC cell lines with a combination index of 0.59 (95% confidence interval [CI] = 0.54 to 0.63) for the PC-9 and 0.59 (95% CI = 0.54 to 0.63) for the H1975 cell line. High expression of STAT3 or YAP1 predicted worse progression-free survival (hazard ratio [HR] = 3.02, 95% CI = 1.54 to 5.93, P = .001, and HR = 2.57, 95% CI = 1.30 to 5.09, P = .007, respectively) in an initial cohort of 64 EGFR-mutant NSCLC patients treated with firstline EGFR TKIs. Similar results were observed in a validation cohort. Conclusions: Our study uncovers a coordinated signaling network centered on both STAT3 and Src-YAP signaling that limits targeted therapy response in lung cancer and identifies an unforeseen rational upfront polytherapy strategy to minimize residual disease and enhance clinical outcomes

Six RNA Viruses and Forty-One Hosts: Viral Small RNAs and Modulation of Small RNA Repertoires in Vertebrate and Invertebrate Systems

We have used multiplexed high-throughput sequencing to characterize changes in small RNA populations that occur during viral infection in animal cells. Small RNA-based mechanisms such as RNA interference (RNAi) have been shown in plant and invertebrate systems to play a key role in host responses to viral infection. Although homologs of the key RNAi effector pathways are present in mammalian cells, and can launch an RNAi-mediated degradation of experimentally targeted mRNAs, any role for such responses in mammalian host-virus interactions remains to be characterized. Six different viruses were examined in 41 experimentally susceptible and resistant host systems. We identified virus-derived small RNAs (vsRNAs) from all six viruses, with total abundance varying from “vanishingly rare” (less than 0.1% of cellular small RNA) to highly abundant (comparable to abundant micro-RNAs “miRNAs”). In addition to the appearance of vsRNAs during infection, we saw a number of specific changes in host miRNA profiles. For several infection models investigated in more detail, the RNAi and Interferon pathways modulated the abundance of vsRNAs. We also found evidence for populations of vsRNAs that exist as duplexed siRNAs with zero to three nucleotide 3′ overhangs. Using populations of cells carrying a Hepatitis C replicon, we observed strand-selective loading of siRNAs onto Argonaute complexes. These experiments define vsRNAs as one possible component of the interplay between animal viruses and their hosts

Politics ahead of patients: The battle between medical and chiropractic professional associations over the inclusion of chiropractic in the American Medicare System

Health care professions struggling for legitimacy, recognition, and market share can become disoriented to their priorities. Health care practitioners are expected to put the interests of patients first. Professional associations represent the interests of their members. So when a professional association is composed of health care practitioners, its interests may differ from those of patients, creating a conflict for members. In addition, sometimes practitioners’ perspectives may be altered by indoctrination in a belief system, or misinformation, so that a practitioner could be confused about the reality of patient needs. Politicians, in attempting to find an expedient compromise, can value a “win” in the legislative arena over the effects of that legislation. These forces all figure into the events that led to the acceptance of chiropractic into the American Medicare system. Two health care systems in a political fight lost sight of their main purpose: to provide care to patients without doing harm. Dans leur recherche de légitimité, de reconnaissance et d’une juste part sur le marché de la santé, les professionnels de la santé peuvent perdre de vue leurs priorités. Ces praticiens doivent donner préséance aux intérêts des patients tandis que les associations professionnelles représentent ceux de leurs membres. Lorsqu’une association professionnelle regroupe des praticiens de la santé cependant, ses intérêts s’opposent parfois à ceux des patients, créant ainsi un conflit pour les membres. De plus, les praticiens peuvent être endoctrinés par un système de valeurs ou mal informés, au point de se tromper dans l’évaluation des besoins réels des patients. De leur côté, les politiciens peuvent préférer une « victoire » dans l’arène législative à une juste appréciation des impacts d’une loi. Ces forces ont toutes participé aux évènements qui ont mené à l’acceptation de la chiropraxie par le système américain Medicare. Dans cette bataille politique, deux systèmes de santé ont négligé leur principal objectif : soigner des patients sans leur nuire

The Untold Story of Qumran

Westwood214 p.: illus.; 28 c

A framework for understanding and targeting residual disease in oncogene-driven solid cancers

Molecular targeted therapy has the potential to dramatically improve survival in patients with cancer. However, complete and durable responses to targeted therapy are rare in individuals with advanced-stage solid cancers. Even the most effective targeted therapies generally do not induce a complete tumor response, resulting in residual disease and tumor progression that limits patient survival. We discuss the emerging need to more fully understand the molecular basis of residual disease as a prelude to designing therapeutic strategies to minimize or eliminate residual disease so that we can move from temporary to chronic control of disease, or a cure, for patients with advanced-stage solid cancers. Ultimately, we propose a shift from the current reactive paradigm of analyzing and treating acquired drug resistance to a pre-emptive paradigm of defining the mechanisms that result in residual disease, to target and limit this disease reservoir