Combination Therapy Strategies Research Articles

Long-Term Outcomes of Patients With Recent-Onset Rheumatoid Arthritis After 10 Years of Tight Controlled Treatment: A Randomized Trial.

Treat-to-target therapy is effective for patients with rheumatoid arthritis (RA), but long-term results of continued targeted treatment are lacking. To evaluate long-term outcomes in patients with early RA after 10 years of targeted treatment in 4 treatment strategies. Randomized trial. (Nederlands Trial Register: NTR262 and NTR265). The Netherlands. 508 patients with early active RA. Sequential monotherapy (strategy 1), step-up combination therapy (strategy 2), or initial combination therapy with prednisone (strategy 3) or with infliximab (strategy 4), all followed by targeted treatment aiming at low disease activity. Functional ability (Health Assessment Questionnaire [HAQ] score) and radiographic progression (Sharp-van der Heijde score) were primary end points. Survival in the study population was compared with the general population using the standardized mortality ratio. 195 of 508 of patients (38%) dropped out of the study (28% in strategy 4 vs. 40% to 45% in strategies 1 to 3, respectively). At year 10, mean HAQ score (SD) was 0.57 (0.56); 53% and 14% of patients were in remission and drug-free remission, respectively, without differences among the strategies. Over 10 years, mean HAQ scores were 0.69, 0.72, 0.64, and 0.58 in strategies 1 to 4, respectively (differences not clinically relevant). Radiographic damage was limited for all strategies, with mean Sharp-van der Heijde estimates during follow-up of 11, 8, 8, and 6 in strategies 1 to 4, respectively (P= 0.15). Standardized mortality ratio was 1.16 (95% CI, 0.92 to 1.46) based on 72 observed and 62 expected deaths, with similar survival among the 4 strategies (P= 0.81). Dropout rate varied by strategy. In patients with early RA, initial (temporary) combination therapy results in faster clinical improvement and targeted treatment determines long-term outcomes. Drug-free remission, with prevention of functional deterioration and clinically relevant radiographic damage, and normalized survival are realistic outcomes. Dutch College of Health Insurance Companies, Schering-Plough, and Janssen.

Synergism between two amphenicol of antibiotics, florfenicol and thiamphenicol, against Staphylococcus aureus

Synergistic effects between the same class of antibiotics are rarely reported. In the current study, two amphenicols, namely florfenicol and thiamphenicol, exhibited both in vitro and in vivo synergism against...

Profilin potentiates chemotherapeutic agents mediated cell death via suppression of NF-κB and upregulation of p53.

The molecular mechanism by which Profilin acts as a tumor suppressor is still unclear. Several chemotherapeutic agents, used till date either have unfavorable side effects or acquired resistance in tumor cells. Our findings show that Profilin enhances cell death mediated by several chemotherapeutic-agents. The activation of NF-κB and its dependent genes, mediated by paclitaxel and vinblastine, was completely inhibited in Profilin overexpressing cells. This inhibition was due to the Profilin mediated attenuation of IκBα degradation, thereby preventing p65 nuclear translocation and low NF-κB DNA binding activity.Moreover, Profilin increases level of p53 in the presence of known inducers, such as doxorubicin, vinblastine, and benzofuran. This increased p53 level leads to enhanced cell death as indicated by activation of caspases 3, 8, 9, which results in cleavage of PARP.Furthermore, knocking down of p53 in Profilin overexpressing cells leads to decreased cell death. Ectopic expression of Profilin in HCT116 p53 knock out cells showed lesser cell death as compared to the HCT116 p53 wild type cells. For the first time, we provide evidences, which suggest that Profilin synergizes with chemotherapeutic drugs to induce tumor cell death by regulating NF-κB and p53. Thus, modulation of Profilin may be a useful strategy for effective combination therapy.

Effective treatment of HER2-amplified breast cancer by targeting HER3 and β1 integrin.

The central role of HER2 as the disease driver and HER3 as its essential partner has made them rational targets for the treatment of HER2-amplifed breast cancers, and there is considerable interest in developing highly effective treatment regimens for this disease that consist of targeted therapies alone. Much of these efforts are focused on dual targeting approaches, particularly dual targeting of the HER2-HER3 tumor driver complex itself, or vertical combinations that target downstream PI3K or Akt in addition to HER2. There is also potential in lateral combinations based on evidence implicating cross-talk with other membrane receptor systems, particularly integrins, and such lateral combinations can potentially involve either HER2 or HER3. We established a preclinical model of targeting HER3 using doxycycline-inducible shRNA and determined the efficacy of a β1 integrin inhibitor in combination with targeting HER3. We report that targeting HER3 and β1 integrin provides a particularly effective combination therapy approach for HER2-amplified cancers, surpassing the combination of HER2 and β1 integrin targeting, and evading some of the safety concerns associated with direct HER2-targeting. This further validates HER3 as a major hub mediating the tumorigenic functions of HER2 and identifies it as a high value target for lateral combination therapy strategies.

Targeting Cancer Stem Cells in Castration-Resistant Prostate Cancer.

Clinical evidence suggests increased cancer stem cells (CSCs) in a tumor mass may contribute to the failure of conventional therapies because CSCs seem to be more resistant than differentiated tumor cells. Thus, unveiling the mechanism regulating CSCs and candidate target molecules will provide new strategy to cure the patients. The stem-like cell properties were determined by a prostasphere assay and dye exclusion assay. To find critical stem cell marker and reveal regulation mechanism, basic biochemical and molecular biologic methods, such as quantitative real-time PCR, Western blot, reporter gene assay, and chromatin immunoprecipitation assay, were used. In addition, to determine the effect of combination therapy targeting both CSCs and its progeny, in vitro MTT assay and in vivo xenograft model was used. We demonstrate immortalized normal human prostate epithelial cells, appeared nontumorigenic in vivo, become tumorigenic, and acquire stem cell phenotype after knocking down a tumor suppressor gene. Also, those stem-like cells increase chemoresistance to conventional anticancer reagent. Mechanistically, we unveil that Wnt signaling is a key pathway regulating well-known stem cell marker CD44 by directly interacting to the promoter. Thus, by targeting CSCs using Wnt inhibitors synergistically enhances the efficacy of conventional drugs. Furthermore, the in vivo mouse model bearing xenografts showed a robust inhibition of tumor growth after combination therapy. Overall, this study provides strong evidence of CSC in castration-resistant prostate cancer. This new combination therapy strategy targeting CSC could significantly enhance therapeutic efficacy of current chemotherapy regimen only targeting non-CSC cells.

Combination Radioimmunotherapy Approaches and Quantification of Immuno-PET.

Monoclonal antibodies (mAbs), which play a prominent role in cancer therapy, can interact with specific antigens on cancer cells, thereby enhancing the patient’s immune response via various mechanisms, or mAbs can act against cell growth factors and, thereby, arrest the proliferation of tumor cells. Radionuclide-labeled mAbs, which are used in radioimmunotherapy (RIT), are effective for cancer treatment because tumor associated-mAbs linked to cytotoxic radionuclides can selectively bind to tumor antigens and release targeted cytotoxic radiation. Immunological positron emission tomography (immuno-PET), which is the combination of PET with mAb, is an attractive option for improving tumor detection and mAb quantification. However, RIT remains a challenge because of the limited delivery of mAb into tumors. The transport and uptake of mAb into tumors is slow and heterogeneous. The tumor microenvironment contributed to the limited delivery of the mAb. During the delivery process of mAb to tumor, mechanical drug resistance such as collagen distribution or physiological drug resistance such as high intestinal pressure or absence of lymphatic vessel would be the limited factor of mAb delivery to the tumor at a potentially lethal mAb concentration. When α-emitter-labeled mAbs were used, deeper penetration of α-emitter-labeled mAb inside tumors was more important because of the short range of the α emitter. Therefore, combination therapy strategies aimed at improving mAb tumor penetration and accumulation would be beneficial for maximizing their therapeutic efficacy against solid tumors.

Challenging the Paradigms of Experimental TBI Models: From Preclinical to Clinical Practice.

Despite prodigious advances in TBI neurobiology research and a broad arsenal of animal models mimicking different aspects of human brain injury, this field has repeatedly experienced collective failures to translate from animals to humans, particularly in the area of therapeutics. This lack of success stems from variability and inconsistent standardization across models and laboratories, as well as insufficient objective and quantifiable diagnostic measures (biomarkers, high-resolution imaging), understanding of the vast clinical heterogeneity, and clinically centered conception of the TBI animal models. Significant progress has been made by establishing well-defined standards for reporting animal studies with "preclinical common data elements" (CDE), and for the reliability and reproducibility in preclinical TBI therapeutic research with the Operation Brain Trauma Therapy (OBTT) consortium. However, to break the chain of failures and achieve a therapeutic breakthrough in TBI will probably require the use of higher species models, specific mechanism-based injury models by which to theranostically targeted treatment portfolios are tested, more creative concepts of therapy intervention including combination therapy and regeneration neurobiology strategies, and the adoption of dosing regimens based upon pharmacokinetic-pharmacodynamic (PK-PD) studies and guided by the injury severity and TBI recovery process.

New Mouse Models to Investigate the Efficacy of Drug Combinations in Human Chronic Myeloid Leukemia.

Chronic myeloid leukemia (CML) comprises a simple and effective paradigm for generating new insights into the cellular origin, pathogenesis, and treatment of many types of human cancer. In particular, mouse models of CML have greatly facilitated the understanding of the underlying molecular mechanisms and pathogenesis of this disease and have led to the identification of new drug targets that in some cases offer the possibility of functional cure. There are currently three established CML mouse models: the BCR-ABL transgenic model, the BCR-ABL retroviral transduction/transplantation model, and the xenotransplant immunodeficient model. Each has its own unique advantages and disadvantages. Depending on the question of interest, some models may be more appropriate than others. In this chapter, we describe a newly developed xenotransplant mouse model to determine the efficacy of novel therapeutic agents, either alone or in combination. The model facilitates the evaluation of the frequency of leukemic stem cells with long-term leukemia-initiating activity, a critical subcellular population that causes disease relapse and progression, through the utilization of primary CD34(+) CML stem/progenitor cells obtained from CML patients at diagnosis and prior to drug treatment. We have also investigated the effectiveness of new combination treatment strategies designed to prevent the development of leukemia in vivo using BCR-ABL (+) blast crisis cells as a model system. These types of in vivo studies are important for the prediction of individual patient responses to drug therapy, and have the potential to facilitate the design of personalized combination therapy strategies.

The combination of radiation therapy and immunotherapy for genitourinary cancer treatment: rationale, current evidence, and prospects

Targeted immunotherapy has emerged as a potentially effective systemic treatment for metastatic cancer in the past decade. However, a significant fraction of patients will either not respond or develop resistance to immunotherapy due to the immune-evasive properties of cancer. Radiation therapy can augment immunotherapy to modulate the immune suppressive tumor microenvironment and promote specific tumor targeting by the adaptive immune system. In this review, we will discuss the rationale for combining radiation therapy with immunotherapy and describe clinical studies using this combination strategy to improve the treatment response by inducing synergistic and abscopal effects. We will discuss ongoing prospective clinical trials that employ the combination of radiation therapy and immunotherapy in the treatment of genitourinary malignancies. Further advances in these combination therapy strategies are expected to improve the clinical response and disease course while further providing insight to the complex interactions and regulations between the immune system and cancer cells. Multiple additional clinical trials will be required to find routine application of this concept to the clinic.

Abstract LB-C12: Functional proteomics elucidates signaling adaptation driven by combination therapy in BRAF mutant melanoma cell line models

Abstract Targeted kinase inhibition is a promising treatment modality for melanoma, which has significantly increased available clinical strategies and improved survival outcomes for patients, whose tumors harbor the BRAF V600E mutation. However, responses are transient and multiple mechanisms for drug resistance can contribute to therapeutic escape. Therefore, a novel multiplexed proteomics approach provides an optimal choice for comprehensively dissecting multiple mechanisms of resistance to BRAFi and combination therapy within one experiment. A large-scale quantitative expression proteomics and phosphoproteomics analysis (SysQuant) was carried out on BRAF V600E mutant melanoma cell lines treated with two different clinically relevant kinase inhibitor combinations: 1) BRAFi/MEKi and 2) BRAFi/PI3Ki. Changes in protein expression and phosphorylation in response to each treatment are determined by comparison to vehicle controls. Cell line models all harbor BRAF V600E mutations, but differ in PTEN status (A375 is WT, while WM793 is PTEN null). Briefly, cells were treated with either drug combination (as above) and harvested at 1hr, 6hrs, 24hrs and 48hrs post-treatment. Control cells were treated with DMSO. Samples were lysed, reduced, alkylated and digested with trypsin. Tryptic peptides from each sample were chemically labeled or “barcoded” with TMT-10plex reagents (4 BRAFi/MEKi time points, 4 BRAFi/PI3Ki time points, 1 DMSO control and a pooled reference sample) and combined for LC-MS/MS. After peptide fractionation with strong cation exchange chromatography and phosphopeptide enrichment, LC-MS/MS peptide sequencing and relative quantification was performed using an Orbitrap Fusion mass spectrometer (Thermo). Raw MS data was searched by Proteome Discoverer and analyzed by in-house R-scripts and Perseus statistical software package. Pathway analysis was done in GeneGO (Metacore). The SysQuant workflow identified >9,000 protein groups and >17,000 unique phosphosites per cell line across different treatments. Principal component analysis of the phosphoproteomics data revealed signaling differences across different treatment conditions and drug combinations are mainly driven by BRAFi and the time post-treatment. K-means clustering was also used to examine trends in the data; as an example, this technique could be used to track signaling changes that correlate with reduction and recovery in ERK signaling. The SysQuant approach provides a systems view of global signaling changes occurring in response to drug treatment. The ability to multiplex samples with TMT allows quantitative deduction of protein expression and phosphorylation patterns that are common or unique in different cell lines, time post-treatment and the effect of combination treatments. This proteomics approach ties protein expression and phosphorylation status in response to combination therapy and generates several hypotheses for further testing with the goal of developing novel combination therapy strategies. Citation Format: Ritin Sharma, Inna Fedorenko, Sasa Koncarevic, Vikram Mitra, Stefan Selzer, Gitte Boehm, Ian Pike, Keiran Smalley, John M. Koomen. Functional proteomics elucidates signaling adaptation driven by combination therapy in BRAF mutant melanoma cell line models. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr LB-C12.

Abstract B2-27: Systems biological identification of optimal drug targets for combination therapy of non-small cell lung cancer

Abstract Non-small cell lung cancer (NSCLC) is the major subtype of lung cancer, accounting for about 85% of all lung patients. Recently, molecularly targeted inhibitors of receptor tyrosine kinase (RTK) such as epidermal growth factor receptor (EGFR) and fibroblast growth factor receptor (FGFR) signalling pathways have been highlighted as promising anti-tumor drugs because of the prevalence of genetic alterations within EGFR and FGFR signalling pathways in NSCLC patients. However, their functional effects have been reported as varying over a wide range depending on the patient-specific mutational conditions. To understand the underlying mechanism of the heterogeneous responses to EGFR and FGFR inhibitors and to find the optimal strategy for combination therapy, we have developed an integrative Boolean network model of EGFR, FGFR and DNA damage signalling pathways by integrating previous experimental evidences from the literature. Systematic perturbation analysis revealed that the multiple feedback regulations embedded in the signalling pathways play important roles in determining the responses to EGFR and FGFR inhibitors. We further analyzed the mechanism for the heterogeneous responses of cells to the EGFR and FGFR inhibitors under various mutational conditions and identified key genetic alterations that can lead to undesirable responses. Finally, extensive combinatorial perturbation analysis and subsequent comparison of the attractor profiles in the presence and absence of targeted inhibitors identified novel candidate drug targets for combinatorial therapy. Our analysis provides a new insight into the underlying mechanism of the heterogeneous cellular responses to EGFR and FGFR inhibitors and the optimal combinatorial treatment strategies. Acknowledgements: This work was supported by the National Research Foundation of Korea (NRF) grants funded by the Korea Government, the Ministry of Science, ICT & Future Planning (2014R1A2A1A10052404, 2013M3A9A7046303, and 2010-0017662) and by a grant of the Korean Health Technology R&D Project, Ministry of Health & Welfare, Republic of Korea. (HI13C2162). Citation Format: Jonghoon Lee, Kwang-Hyun Cho. Systems biological identification of optimal drug targets for combination therapy of non-small cell lung cancer. [abstract]. In: Proceedings of the AACR Special Conference on Computational and Systems Biology of Cancer; Feb 8-11 2015; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(22 Suppl 2):Abstract nr B2-27.

Abstract B28: Determining the apoptotic mechanisms of bromodomain and extraterminal (BET) inhibitors

Abstract Inhibitors of the bromodomain and extraterminal domain family (BETi), represent a novel class of targeted therapy to treat aggressive B-cell lymphomas. Specifically, BETi are shown to inhibit proliferation and induce apoptosis in lymphoma cells arising from Myc transgenic mice. However, the underlying apoptotic mechanisms are still not well understood. Dissecting apoptotic mechanisms required by BETi could provide strong rationale on how to best utilize BETi to treat patients with aggressive B-cell lymphomas. It was the primary purpose of this study to delineate the molecular mechanisms underlying BETi induced apoptosis. Secondly, by determining critical apoptotic proteins/pathways, investigate the potential of BETi in novel combination therapy strategies. For this, we conducted in vitro studies utilizing primary and compound mutant lymphomas derived from the Eµ-myc murine model of B-cell lymphoma. The BETi IBET762 was used to treat lymphomas, and over all cell death, apoptosis, mitochondria damage, cell cycle distribution were assessed by flow cytometry. Protein expression of Myc, bromodomain 3 and 4 (BRD 3 and BRD4), Bcl-2 and activated caspase 3 were assessed by western blot. IBET762 induces apoptosis in Eµ-myc lymphomas in a time and dose dependent manner at low nanomolar concentrations. Apoptosis was dependent on the intrinsic apoptotic pathway, but independent of p53 or p19arf. Loss of apoptosome function delayed the kinetics of BETi mediated cell death. Analysis of BRD3, BRD4, Bcl-2 and Myc protein expression is ongoing. Because apoptosis induction by BETi was blocked by the overexpression of Bcl-2, we tested the efficacy of the small molecule Bcl-2 inhibitor, ABT-263. Combining low dose ABT-263 with IBET762 resulted in induction of apoptosis in Eµ-myc/Bcl-2 lymphomas. These data indicate mitochondrial damage to be critical for BETi mediated apoptosis. Finally, our current studies will provide vision and strong rationale on how best to apply BET inhibitors to the clinic to provide maximum benefit to patients with aggressive B-cell lymphomas. Citation Format: Elena Lasorsa, Leigh Ellis. Determining the apoptotic mechanisms of bromodomain and extraterminal (BET) inhibitors. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr B28.

AMBITION: An important piece in the therapeutic puzzle of pulmonary arterial hypertension.

It is believed that simultaneous targeting of two or more of the three pathogenic pathways of pulmonary arterial hypertension (the endothelin, nitric oxide, and prostacyclin pathways) is associated with additive or synergistic effects with subsequent increasing efficacy and improving outcomes. However, there is lack of evidence to guide the use of combination strategy among pulmonary arterial hypertension patients and many questions remain to be answered. One of these vital questions is whether the strategy of upfront initiation of combination therapy could improve patients outcomes compared to the strategy of initial monotherapy. The recently published AMBITION trial represents an important forward step towards answering this question by comparing a strategy of first-line combination therapy (ambrisentan and tadalafil) versus first-line monotherapy (ambrisentan or tadalafil) in patients with pulmonary arterial hypertension.

Progress in Intravenous Thrombolytic Therapy for Acute Stroke.

Intravenous recombinant tissue plasminogen activator (alteplase) was approved by the US Food and Drug Administration in 1996 for the treatment of acute ischemic stroke. Nearly 20 years later, it remains the only approved treatment, despite limitations in both efficacy and safety. With a growing capacity for stroke treatment worldwide, physicians need to understand where we have come from and what the future of stroke treatment might be. To present a historical prospective as well as current trends in thrombolytic therapy, focusing on characteristics of drugs that have worked and clinical trials that are moving the field forward. Sources are published pivotal clinical trials; seminal articles on physiology, pharmacology, and neuroimanging; and listings from clinical trial registries. The slow progress in thrombolysis for acute stroke has been multifactorial. A focus on extending the time window for alteplase beyond 4.5 hours has encumbered substantial resources in the field for many years, yet these efforts have been largely unsuccessful. New drug development has also been slow. Several drugs have failed in clinical trials and currently only tenecteplase remains to be tested as a potential alternative to alteplase. The parallel pursuit for catheter-based interventional revascularization in acute stroke, which appears to be successful, has shifted emphasis away from pharmacologically based studies. Although the field of acute thrombolysis has been making progress slowly for many years, advances in neuroimaging and new clinical trials that combine thrombolytics with other pharmacological and interventional techniques are beginning to gain momentum once again. The emergence of new approaches based largely on combination therapy strategies has reset a course to advance thrombolytic treatment for acute stroke and promises to improve outcomes in acute stroke in the near future.

Abstract IA22: Targeting mTOR for breast cancer therapy

Abstract The Phosphatidylinositol 3-kinase (PI3K)/Akt/ mammalian target of rapamycin (mTOR) pathway plays a central role in cell metabolism, growth, proliferation, and survival. Activation of PI3K/Akt/mTOR signaling contributes to the oncogenesis of many tumor types, and thus the pathway is being actively pursued as a promising therapeutic target. mTOR, an important component of this pathway, exists in two multiprotein complexes: mTOR complex 1 and mTOR complex 2 (mTORC1 and mTORC2). mTORC1 controls cell growth, survival, and protein translation by regulating the phosphorylation of two major substrates: S6 kinase (S6K) and 4E-BP1. mTORC2 phosphorylates Akt at Serine 473 (S473), enhancing the catalytic activity of Akt, that has already been phosphorylated at Threonine 308 (T308). Thus, the mTOR complexes play an important role both upstream and downstream of Akt. Rapamycin and its analogs are allosteric mTOR inhibitors that bind FKBP12 and mTOR, and predominantly inhibit mTORC1. The rapamycin analog temsirolimus is approved by the Food and Drug Administration for the treatment of advanced renal cell carcinoma and the rapamycin analog everolimus is FDA approved for the treatment of pancreatic neuroendocrine tumors, renal cell carcinoma, sub-ependymal giant cell astrocytoma associated with tuberous sclerosis, as single agent therapy, and for the treatment of hormone-receptor positive breast cancer as combination therapy with exemestane. In spite of proven clinical benefit in breast cancer, objective responses remain rare. Thus there remains a need to identify predictors of response, optimal strategies for mTOR inhibition and rational combination therapies. There is emerging data on predictors of response to rapalog. Although preclinical studies suggest PIK3CA and PTEN alterations may confer sensitivity to rapalogs, the predictive value of these markers in the clinic has been controversial. Rare alterations such as mTOR activating mutations and TSC1 have been reported to confer sensitivity, while mTOR mutations in FKBP domain may confer rapalog resistance. The optimal strategy to target mTOR signaling is unknown. Preclinically, mTOR catalytic site inhibitors are more effective in cell lines with intrinsic or acquired rapamycin-resistance. The relative efficacy of other PI3K/Akt/mTOR inhibitors in breast cancer compared to rapalogs is not yet understood. Combinations with chemotherapy and other targeted agents are ongoing. Citation Format: Funda Meric-Bernstam. Targeting mTOR for breast cancer therapy. [abstract]. In: Proceedings of the AACR Special Conference: Targeting the PI3K-mTOR Network in Cancer; Sep 14-17, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(7 Suppl):Abstract nr IA22.

A Phytochemical-Halogenated Quinoline Combination Therapy Strategy for the Treatment of Pathogenic Bacteria.

With the continued rise of drug-resistant bacterial infections coupled with the current discouraging state of the antibiotic pipeline, the need for new antibacterial agents that operate through unique mechanisms compared with conventional antibiotics and work in synergy with other agents is at an all-time high. We have discovered that gallic acid, a plant-derived phytochemical, dramatically potentiates the antibacterial activities of several halogenated quinolines (up to 11,800-fold potentiation against Staphylococcus aureus) against pathogenic bacteria, including drug-resistant clinical isolates. S. aureus demonstrated the highest sensitivity towards gallic acid-halogenated quinoline combinations, including one halogenated quinoline that demonstrated potentiation of biofilm eradication activity against a methicillin-resistant S. aureus (MRSA) clinical isolate. During our studies, we also demonstrated that these halogenated quionlines operate through an interesting metal(II) cation-dependent mechanism and display promising mammalian cytotoxicity.

TKI Resistance for T790M Mutation

表皮生长因子受体（epidermal growth factor receptor, EGFR）的口服活性小分子抑制剂的开发为非小细胞肺癌（non-small cell lung cancer, NSCLC）提供了新的治疗方案。EGFR基因发生激活突变的患者对EGFR酪氨酸激酶抑制剂（epidermal growth factor receptor tyrosine kinase inhibitors, EGFR-TKIs）治疗敏感，该疗法使大量患者临床获益。第一代可逆型ATP-竞争型EGFR-TKIs，吉非替尼和厄洛替尼作为一线、二线或维持疗法具有疗效。尽管这些药物具有初始疗效，但大多数患者在1年内会产生抗药性，50%-60%的患者都与T790M管家基因出现突变有关。新近的不可逆型EGFR-TKIs-阿法替尼和dacomitinib可共价结合并抑制多个ErbB家族的受体（EGFR、HER2和HER4）。人们主要评价这些药物作为一线治疗的意义，以及在对第一代EGFR-TKIs产生获得性抗药性情况下的意义。阿法替尼是获批的第一种ErbB家族阻断剂，用于治疗带有EGFR激活突变的NSCLC患者；dacomitinib正处在临床开发的后期阶段。特异性靶向T790M抗药性突变的EGFR抑制剂（AZD9291、CO-1686、HM61713）正处在早期开发阶段。正如本文中的讨论，EGFR-TKIs靶向的激酶范围不同，它们结合EGFR受体的可逆性和药物相互作用的潜能也不同。对于临床医生来说，这些差异对经多种药物治疗的NSCLC患者具有意义，从创新型抗癌药物联合治疗策略的角度看，这些差异也极具意义。

The phosphoinositide 3-kinase pathway and therapy resistance in cancer.

The phosphoinositide 3-kinase (PI3K)/Akt/mechanistic target of rapamycin (mTOR) signaling network is a master regulator of processes that contribute to tumorigenesis and tumor maintenance. The PI3K pathway also plays a critical role in driving resistance to diverse anti-cancer therapies. This review article focuses on mechanisms by which the PI3K pathway contributes to therapy resistance in cancer, and highlights potential combination therapy strategies to circumvent resistance driven by PI3K signaling. In addition, resistance mechanisms that limit the clinical efficacy of small molecule inhibitors of the PI3K pathway are discussed.

Resistance of SMMC-7721 hepatoma cells to etoposide in hypoxia is reversed by VEGF inhibitor.

Hypoxia is associated with resistance to chemotherapy in a number of human cancer types; particularly in hepatocellular carcinoma (HCC), which is a highly vascularized tumor. To develop a potential combination therapy strategy that is capable of overcoming the hypoxia‑induced insensitivity to chemotherapy, the HCC cell SMMC‑7721 was employed to investigate the hypoxia‑induced chemoresistance to etoposide. Increased levels of hypoxia‑inducible factor‑1α (HIF‑1α) and vascular endothelial growth factor (VEGF) were observed when SMMC‑7721 cells were exposed to hypoxia, and exposure of tumor cells to hypoxia impaired etoposide‑induced DNA damage, as indicated by the failure of upregulation of γHA2X. Etoposide‑induced apoptosis and cell cycle arrest of SMMC‑7721 was also impaired in hypoxia. However, co‑treatment with anti‑VEGF significantly restored etoposide‑induced cell apoptosis and cell cycle arrest, as indicated by the elimination of B‑cell lymphoma 2 (Bcl‑2), procaspase 3, cyclin B1 and Cdc2. Furthermore, anti‑VEGF eliminated phosphorylation of AKT, ERK and IκB‑α resulting from hypoxia, suggesting the involvement of VEGF in the activation of the survival pathways. In conclusion, the present study suggests a significant role of VEGF in the chemoresistance of etoposide in hypoxia. A rational chemotherapy should be developed based on a combination of etoposide and anti‑VEGF.

Anti-IGF-1R monoclonal antibody inhibits the carcinogenicity activity of acquired trastuzumab-resistant SKOV3.

BackgroundAntibody resistance, not only de novo but also acquired cases, usually exists and is related with lower survival rate and high risk of recurrence. Reversing the resistance often results in better clinical therapeutic effect. Previously, we established a trastuzumab-resistant ovarian cancer cell line, named as SKOV3-T, with lower HER2 and induced higher IGF-1R expression level to keep cell survival.MethodsIGF-1R was identified important for SKOV3-T growth. Then, a novel anti-IGF-1R monoclonal antibody, named as LMAb1, was used to inhibit SKOV3-T in cell growth/proliferation, migration, clone formation and in vivo carcinogenicity.ResultsIn both in vitro and in vivo assays, LMAb1 showed effective anti-tumor function, especially when being used in combination with trastuzumab, which was beneficial to longer survival time of mice as well as smaller tumor. It was also confirmed preliminarily that the mechanism of antibody might be to inhibit the activation of IGF-1R and downstream MAPK, AKT pathway transduction.ConclusionWe achieved satisfactory anti-tumor activity using trastuzumab plus LMAb1 in trastuzumab-resistant ovarian cancer model. In similar cases, not only acquired but also de novo, good curative effect might be achieved using combined antibody therapy strategies.