Targeted inhibition of kinases in cancer therapy

Synthesis of novel spirochromane incorporating Schiff's bases, potential antiproliferative activity, and dual EGFR/HER2 inhibition: Cell cycle analysis and in silico study

Spirochromanes incorporating Schiff's bases and semicarbazones 4a-e and 5a-j were synthesizedand analyzed for their potential antiproliferative activity using four human cancer cell lines (MCF-7, HCT-116, PC3, and A549). Compounds 5a, 5b and 5g possessed the highest antiproliferative activity among the tested compounds,with an IC50 range of 1.154-9.09 μM. Compound 5j selectively inhibited the PC3 cell proliferation (IC50 = 5.47 μM). Spirochromanes 5a, 5b and 5g exhibited high inhibitory activity against EGFR (IC50 = 0.116, 0.132, and 0.077 μM, respectively) and HER2 (IC50 = 0.055, 0.210 and 0.085 μM, respectively) compared with the references, erlotinib (IC50 = 0.090 and 0.038 μM, respectively) and gefitinib (IC50 = 0.052 and 0.072 μM, respectively). Cell cycle analysis and apoptosis results showed that compounds 5a, 5b and 5g arrested growth inthe S phase, and the programmed cell death induced by these compounds was an apoptotic mechanism rather than a necrotic pathway. Molecular docking studies of spirochromanes 5a, 5b and 5g to EGFR and HER2 binding sites were performed to explore the orientation mode and interaction.

Cardiotoxicity of Biological Therapies in Cancer Patients: An In-depth Review

Cardiotoxicity from chemotherapy regimens has been long reported. However, the understanding of cardiac side effects of biological therapies is rapidly evolving. With cancer patients achieving higher life expectancy due to the use of personalized medicine and novel targeted anticancer agents, the occurrence of cardiotoxicity is becoming more significant. Novel biological therapies include anti-HER2 antibodies, tyrosine kinase inhibitors, bruton kinase inhibitors, antivascular endothelial growth factors, proteasome inhibitors, immunomodulator drugs, and immune checkpoint inhibitors. Potential cardiovascular toxicities linked to these anticancer agents include hypertension, arrhythmias, QT prolongation, myocardial ischemia and infarction, left ventricular dysfunction, congestive heart failure, and thromboembolism. Cardiac biomarkers, electrocardiography, echocardiography and magnetic resonance imaging are common diagnostic modalities used for early detection of these complications and timely intervention. This review discusses the various types of cardiotoxicities caused by novel anticancer biologic agents, their molecular and pathophysiological mechanisms, risk factors, and diagnostic and management strategies that can be used to prevent, minimize, and treat them.

Synthesis of some quinazolinones inspired from the natural alkaloid L-norephedrine as EGFR inhibitors and radiosensitizers

A set of quinazolinones synthesized by the aid of L-norephedrine was assembled to generate novel analogues as potential anticancer and radiosensitizing agents. The new compounds were evaluated for their cytotoxic activity against MDA-MB-231, MCF-7, HepG-2, HCT-116 cancer cell lines and EGFR inhibitory activity. The most active compounds 5 and 6 were screened against MCF-10A normal cell line and displayed lower toxic effects. They proved their relative safety with high selectivity towards MDA-MB-231 breast cancer cell line. Measurement of the radiosensitizing activity for 5 and 6 revealed that they could sensitize the tumour cells after being exposed to a single dose of 8 Gy gamma radiation. Compound 5 was able to induce apoptosis and arrest the cell cycle at the G2-M phase. Molecular docking of 5 and 6 in the active site of EGFR was performed to gain insight into the binding interactions with the key amino acids.

Discovery of 12O-A Novel Oral Multi-Kinase Inhibitor for the Treatment of Solid Tumor

A novel series of pyrimidine-benzotriazole derivatives have been synthesized and evaluated for their anticancer activity against human solid tumor cell lines. The most promising molecule 12O was identified for its excellent antiproliferative activities, especially against the SiHa cell line with IC₅₀ value as 0.009 μM. Kinase inhibition assay assessed 12O was a potential multi-kinase inhibitor, which possessed potent inhibitory activities against cyclin-dependent kinases (CDKs) and fms-like tyrosine kinase (FLT) with IC₅₀ values in the nanomolar range. Molecular docking studies illustrated that the introduction of triazole moiety in 12O was critical for CDKs inhibition. In addition, 12O inhibited cancer cell proliferation, colony-formation, and cell cycle progression and provoked apoptotic death in vitro. In an SiHa xenograft mouse model, a once-daily dose of compound 12O at 20 mg/kg significantly suppressed the tumor growth without obvious toxicity. Taken together, 12O provided valuable guide for further structural optimization for CDKs and FLT inhibitors.

Innovative CAR-T Cell Therapy for Solid Tumor; Current Duel between CAR-T Spear and Tumor Shield

Novel engineered T cells containing chimeric antigen receptors (CAR-T cells) that combine the benefits of antigen recognition and T cell response have been developed, and their effect in the anti-tumor immunotherapy of patients with relapsed/refractory leukemia has been dramatic. Thus, CAR-T cell immunotherapy is rapidly emerging as a new therapy. However, it has limitations that prevent consistency in therapeutic effects in solid tumors, which accounts for over 90% of all cancer patients. Here, we review the literature regarding various obstacles to CAR-T cell immunotherapy for solid tumors, including those that cause CAR-T cell dysfunction in the immunosuppressive tumor microenvironment, such as reactive oxygen species, pH, O₂, immunosuppressive cells, cytokines, and metabolites, as well as those that impair cell trafficking into the tumor microenvironment. Next-generation CAR-T cell therapy is currently undergoing clinical trials to overcome these challenges. Therefore, novel approaches to address the challenges faced by CAR-T cell immunotherapy in solid tumors are also discussed here.

Novel CDKs inhibitors for the treatment of solid tumour by simultaneously regulating the cell cycle and transcription control

A novel series of cyclin-dependent kinases (CDKs) inhibitors, which play critical roles in the cell cycle control and regulation of cell transcription, were synthesised. A systematic study of enzymatic and cellular assays led to the identification of compound X22 with a nanomolar potency against CDK4 and CDK9 and potent antiproliferative activities against a panel of tumour cell lines. X22 could induce cell cycle arrest and cell apoptosis in cancer cell lines. X22 dose-dependently inhibits signalling pathways downstream of CDKs in cancer cells. In vivo antitumor activity assays, oral administration of X22 led to significant tumour regression in mouse model without obvious toxicity. Superior anti-cancer efficacy in vitro and in vivo of X22 demonstrated combined depletion of cell cycle and transcriptional CDK all contributed to antitumor activity. Taken together, concomitant inhibition of cell cycle and transcriptional CDK activities provided valuable guide for further structural optimisation.

Red-light-sensitive BODIPY photoprotecting groups for amines and their biological application in controlling heart rhythm

Protection of amine functionality with a BODIPY-derived photocleavable protecting group enables the control of heart beat frequency with red light.

Anticancer profile of newly synthesized BRAF inhibitors possess 5-(pyrimidin-4-yl)imidazo[2,1-b]thiazole scaffold

In this work, a new series of imidazo[2,1-b]thiazole was designed and synthesized. The new compounds are having 3-fluorophenyl at position 6 of imidazo[2,1-b]thiazole and pyrimidine ring at position 5. The pyrimidine ring containing either amide or sulphonamide moiety attached to a linker (ethyl or propyl) at position 2 of the pyrimidine ring. The final compounds were selected by NCI for in vitro cytotoxicity screening. Most derivatives showed cytotoxic activity against colon cancer and melanoma cell lines. In addition, IC₅₀s of the target compounds were determined over A375 and SK-MEL-28 cell lines using sorafenib as positive control. Compounds12b, 12c, 12e, 12f, 15a, 15d, 15f, 14g and 15h exhibited superior activity when compared to sorafenib. The most potent compounds were tested against wild type BRAF, v600e BRAF, and CRAF. Compound 15h exhibited a potential inhibitory effect against^V600EBRAF (IC₅₀ = 9.3 nM).

Kinase Inhibitory Activities and Molecular Docking of a Novel Series of Anticancer Pyrazole Derivatives

A series of novel 1,3,4-triarylpyrazoles containing different heterocycles has been prepared, characterized and screened for their in vitro antiproliferative activity against HePG-2, MCF-7, PC-3, A-549 and HCT-116 cancer cell lines. The biological results revealed that compound 6 showed the highest anticancer activity so it was subjected to a kinase assay study where it reduced the activity of several protein kinases including AKT1, AKT2, BRAF V600E, EGFR, p38α and PDGFRβ at 100 μM using the radiometric or ADP-Glo assay method. Molecular docking simulation supported the initial kinase assay and suggested a common mode of interaction at the ATP-binding sites of these kinases, which demonstrates that compound 6 is a potential agent for cancer therapy deserving further research.

From a Patient Advocate's Perspective: Does Cancer Immunotherapy Represent a Paradigm Shift?

PURPOSE OF REVIEW

In 2016, the American Society of Clinical Oncology (ASCO) announced immunotherapy as the year's top cancer advance in its "Clinical Cancer Advances 2016: ASCO's Annual Report on Progress Against Cancer." Further, ASCO again named "Immunotherapy 2.0" as the 2017 advance of the year, emphasizing the recent, rapid pace of research into new agents that harness and enhance the innate abilities of the immune system to recognize and fight cancers-and stressing that such agents have extended the lives of many patients with late-stage cancers for which there have been few treatment options. This article discusses the history of cancer immunotherapy and the recent promising advances, yet also presents a note of caution on limitations of immunotherapies, their potential harms, and the critical need for oncologists to appropriately engage with and educate patients to effectively manage their expectations.

RECENT FINDINGS

Learning how to effectively harness the immune system to treat cancer represents an investigative journey of more than 100 years. However, after many failures and disappointments, this decade has seen several important successes. In 2011, the Food and Drug Administration (FDA) approved the first immunotherapy agent known as a "checkpoint inhibitor." Beginning in 2014, several additional checkpoint blockage drugs have been FDA-approved, and new indications and drug combinations have emerged. Further, on August 30, 2017, the FDA announced its first approval of a new form of immunotherapy known as CAR T cell therapy. Since the 2011 approval of the first checkpoint inhibitor, cancer immunotherapy research among the pharmaceutical industry and research institutions has exploded, with thousands of clinical trials currently taking place. The current "cancer immunotherapy revolution" is in the headlines daily and is also the primary topic of conversation among major cancer research conferences and symposia attendees. However, a once quiet voice has begun to emerge, where an increasing number of scientists, clinicians, and patient advocates are stressing the need for caution concerning the limitations and potential harms associated with cancer immunotherapy. Many oncologists, scientists, medical professional associations, and advocates agree that no recent cancer advance has been as successful, transformative, and potentially paradigm-shifting as immunotherapy. With this decade, we have seen the approval of several immunotherapy agents that have successfully treated a percentage of patients with notoriously resistant cancers, an increasing number of combination immunotherapy treatments, and new indications for approved agents. However, patients need to be aware that much of the popular media has breathlessly inflated positive outcomes of cancer immunotherapies, while neglecting to stress that just a small percentage of patients actually benefit from such treatments. Further, they often completely overlook the unique, potentially life-threatening harms that may be associated with these agents and fail to cover negative findings where immunotherapies have appeared to paradoxically accelerate cancer growth. Fortunately, the majority of journal articles presenting trial results and comprehensive review articles appropriately discuss the important limitations associated with immunotherapies, the unique spectrum of adverse effects, and the need for further research to improve our ability to identify those patients who are most likely to benefit from specific agents, sparing other patients from exposure to agents that will not be effective, yet may carry potentially life-threatening toxicities.

New Strategies Using Antibody Combinations to Increase Cancer Treatment Effectiveness

Antibodies have proven their high value in antitumor therapy over the last two decades. They are currently being used as the first-choice to treat some of the most frequent metastatic cancers, like HER2⁺ breast cancers or colorectal cancers, currently treated with trastuzumab (Herceptin) and bevacizumab (Avastin), respectively. The impressive therapeutic success of antibodies inhibiting immune checkpoints has extended the use of therapeutic antibodies to previously unanticipated tumor types. These anti-immune checkpoint antibodies allowed the cure of patients devoid of other therapeutic options, through the recovery of the patient’s own immune response against the tumor. In this review, we describe how the antibody-based therapies will evolve, including the use of antibodies in combinations, their main characteristics, advantages, and how they could contribute to significantly increase the chances of success in cancer therapy. Indeed, novel combinations will consist of mixtures of antibodies against either different epitopes of the same molecule or different targets on the same tumor cell; bispecific or multispecific antibodies able of simultaneously binding tumor cells, immune cells or extracellular molecules; immunomodulatory antibodies; antibody-based molecules, including fusion proteins between a ligand or a receptor domain and the IgG Fab or Fc fragments; autologous or heterologous cells; and different formats of vaccines. Through complementary mechanisms of action, these combinations could contribute to elude the current limitations of a single antibody which recognizes only one particular epitope. These combinations may allow the simultaneous attack of the cancer cells by using the help of the own immune cells and exerting wider therapeutic effects, based on a more specific, fast, and robust response, trying to mimic the action of the immune system.

Histone Deacetylase Inhibitor SAHA as Potential Targeted Therapy Agent for Larynx Cancer Cells

Objective: Laryngeal squamous cell carcinoma is one of the most common malignant tumors in the head and neck region. Due to the poor response to chemotherapeutics in patients and low survival rate, successful treatment of larynx cancer still remains a challenge. Therefore, the identification of novel treatment options is needed. We investigated the anticancer effects of suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor, on two different laryngeal cancer cell lines RK33 and RK45. We also studied the antiproliferative action of SAHA in combination with cisplatin and defined the type of pharmacological interaction between these drugs. Materials and Methods: Viability and proliferation of larynx cancer cell lines were studied by methylthiazolyldiphenyl-tetrazolium bromide method and 5-bromo-2-deoxyuridine incorporation assay, respectively. The type of interaction between SAHA and cisplatin was determined by an isobolographic analysis. Western blotting, flow cytometry and quantitative polymerase chain reaction method were used to determine acetylation of histone H3, cell cycle progression and genes expression, respectively. Apoptosis was assessed by means of nucleosomes released to cytosol. Results: SAHA alone or in combination with cisplatin inhibited larynx cancer cells proliferation, whereas displayed relatively low toxicity against normal cells - primary cultures of human skin fibroblasts. The mixture of SAHA with cisplatin exerted additive and synergistic interaction in RK33 and RK45 cells, respectively. We showed that SAHA induced hyperacetylation of histone H3 K9, K14 and K23 and triggered apoptosis. SAHA also caused cell cycle arrest by upregulation of CDKN1A and downregulation of CCND1 encoding p21WAF1/CIP1 and cyclin D1 proteins, respectively. Conclusion: Our studies demonstrated that SAHA may be considered as a potential therapeutic agent against larynx tumors.

Dasatinib for the treatment of chronic myeloid leukemia: patient selection and special considerations

Dasatinib is one of the second-generation tyrosine kinase inhibitors used in imatinib resistance and/or intolerance, as well as in the frontline setting in patients with chronic myeloid leukemia-chronic phase, and also in patients with advanced disease. It is also utilized in Philadelphia chromosome-positive acute lymphocytic leukemia. While choosing the appropriate tyrosine kinase inhibitor (ie, dasatinib) for each individual patient, comorbidities and BCR-ABL1 kinase domain mutations should always be taken into consideration, among other things. This review mainly focuses on patient selection prior to dasatinib administration in the treatment of chronic myeloid leukemia.

Extracellular Visfatin-Promoted Malignant Behavior in Breast Cancer Is Mediated Through c-Abl and STAT3 Activation

PURPOSE

Visfatin is an adipocytokine involved in cellular metabolism, inflammation, and cancer. This study investigated the roles of extracellular visfatin in breast cancer, and explored underlying mechanisms in clinical and experimental settings.

EXPERIMENTAL DESIGN

Associations of serum visfatin with clinicopathologic characteristics and patient survival were assessed with Cox regression models and Kaplan-Meier analyses. Effects of extracellular visfatin on cultured breast cancer cells were examined, followed by in vivo investigation of tumor growth and metastasis in xenograft animal models. Imatinib and Stattic were used to inhibit c-Abl and STAT3 activation, respectively.

RESULTS

Breast cancer patients with high serum visfatin levels were associated with advanced tumor stage, increased tumor size and lymph node metastasis, and poor survival. Elevated phosphorylation of c-Abl and STAT3 in breast tumor tissues were correlated with high serum visfatin levels in patients. Visfatin-promoted in vitro cell viability and metastatic capability were suppressed by imatinib (c-Abl inhibitor) and Stattic (STAT3 inhibitor). Increased in vivo cell invasiveness was observed in zebrafish xenografted with visfatin-pretreated breast cancer cells. Tumor growth and lung metastasis occurred in visfatin-administered mice xenografted with breast cancer cells. Tail vein-injected mice with visfatin-pretreated breast cancer cells showed increased lung metastasis, which was suppressed by imatinib.

CONCLUSIONS

Serum visfatin levels in breast cancer patients reveal potential prognostic values, and our findings that visfatin promoted breast cancer through activation of c-Abl and STAT3 may provide an important molecular basis for future design of targeted therapies that take into account different serum visfatin levels in breast cancer. Clin Cancer Res; 22(17); 4478-90. ©2016 AACR.

Synthesis and biological evaluation of 4-(2′,4′-difluorobiphenyl-4-yl)-6-arylpyrimidin- 2-amine derivatives

4-(2′,4′-Difluorobiphenyl-4-yl)-6-arylpyrimidin-2-amines

Erlotinib Pretreatment Improves Photodynamic Therapy of Non-Small Cell Lung Carcinoma Xenografts via Multiple Mechanisms

Aberrant expression of the epidermal growth factor receptor (EGFR) is a common characteristic of many cancers, including non-small cell lung carcinoma (NSCLC), head and neck squamous cell carcinoma, and ovarian cancer. Although EGFR is currently a favorite molecular target for the treatment of these cancers, inhibition of the receptor with small-molecule inhibitors (i.e., erlotinib) or monoclonal antibodies (i.e., cetuximab) does not provide long-term therapeutic benefit as standalone treatment. Interestingly, we have found that addition of erlotinib to photodynamic therapy (PDT) can improve treatment response in typically erlotinib-resistant NSCLC tumor xenografts. Ninety-day complete response rates of 63% are achieved when erlotinib is administered in three doses before PDT of H460 human tumor xenografts, compared with 16% after PDT-alone. Similar benefit is found when erlotinib is added to PDT of A549 NCSLC xenografts. Improved response is accompanied by increased vascular shutdown, and erlotinib increases the in vitro cytotoxicity of PDT to endothelial cells. Tumor uptake of the photosensitizer (benzoporphyrin derivative monoacid ring A; BPD) is increased by the in vivo administration of erlotinib; nevertheless, this elevation of BPD levels only partially accounts for the benefit of erlotinib to PDT. Thus, pretreatment with erlotinib augments multiple mechanisms of PDT effect that collectively lead to large improvements in therapeutic efficacy. These data demonstrate that short-duration administration of erlotinib before PDT can greatly improve the responsiveness of even erlotinib-resistant tumors to treatment. Results will inform clinical investigation of EGFR-targeting therapeutics in conjunction with PDT.

Oncogene withdrawal engages the immune system to induce sustained cancer regression

The targeted inactivation of a single oncogene can induce dramatic tumor regression, suggesting that cancers are “oncogene addicted.” Tumor regression following oncogene inactivation has been thought to be a consequence of restoration of normal physiological programs that induce proliferative arrest, apoptosis, differentiation, and cellular senescence. However, recent observations illustrate that oncogene addiction is highly dependent upon the host immune cells. In particular, CD4⁺ helper T cells were shown to be essential to the mechanism by which MYC or BCR-ABL inactivation elicits “oncogene withdrawal.” Hence, immune mediators contribute in multiple ways to the pathogenesis, prevention, and treatment of cancer, including mechanisms of tumor initiation, progression, and surveillance, but also oncogene inactivation-mediated tumor regression. Data from both the bench and the bedside illustrates that the inactivation of a driver oncogene can induce activation of the immune system that appears to be essential for sustained tumor regression.

An essential role for the immune system in the mechanism of tumor regression following targeted oncogene inactivation

Tumors are genetically complex and can have a multitude of mutations. Consequently, it is surprising that the suppression of a single oncogene can result in rapid and sustained tumor regression, illustrating the concept that cancers are often "oncogene addicted." The mechanism of oncogene addiction has been presumed to be largely cell autonomous as a consequence of the restoration of normal physiological programs that induce proliferative arrest, apoptosis, differentiation, and/or cellular senescence. Interestingly, it has recently become apparent that upon oncogene inactivation, the immune response is critical in mediating the phenotypic consequences of oncogene addiction. In particular, CD4(+) T cells have been suggested to be essential to the remodeling of the tumor microenvironment, including the shutdown of host angiogenesis and the induction of cellular senescence in the tumor. However, adaptive and innate immune cells are likely involved. Thus, the effectors of the immune system are involved not only in tumor initiation, tumor progression, and immunosurveillance, but also in the mechanism of tumor regression upon targeted oncogene inactivation. Hence, oncogene inactivation may be an effective therapeutic approach because it both reverses the neoplastic state within a cancer cell and reactivates the host immune response that remodels the tumor microenvironment.

Increased expression of SHP-1 is associated with local recurrence after radiotherapy in patients with nasopharyngeal carcinoma

Background

Nasopharyngeal carcinoma (NPC) is a major cancer in southern China. Src homology phosphatase-1 (SHP-1) is a tyrosine phosphatase that regulates growth, differentiation, cell cycle progression, and oncogenesis. We determined the clinical significance of SHP-1 expression in the tumours of NPC patients from southern China who were treated with radiotherapy.

Patients and methods.

SHP-1 expression was determined by real-time polymerase chain reaction (PCR) and western blotting of NPC tissue samples of 50 patients and nasopharyngeal tissues of 50 non-NPC patients who had chronic nasopharyngeal inflammation. SHP-1 expression was measured in NPC tissue samples of 206 patients by immunohistochemistry and survival analysis was performed.

Results

The tumours of NPC patients had significantly increased expression of SHP-1 at mRNA and protein levels relative to patients with chronic nasopharyngeal inflammation. Survival analysis of NPC patients indicated that SHP-1 expression was significantly associated with poor local recurrence-free survival (p = 0.008), but not with nodal recurrence-free survival, distant metastasis-free survival, or overall survival.

Conclusions

SHP-1 appears to be associated with radiation resistance of NPC cells and can be considered as a candidate marker for prognosis and/or therapeutic target in patients with this type of cancer.

Noncanonical roles of the immune system in eliciting oncogene addiction

Cancer is highly complex. The magnitude of this complexity makes it highly surprising that even the brief suppression of an oncogene can sometimes result in rapid and sustained tumor regression, illustrating that cancers can be 'oncogene addicted' [1-10]. The essential implication is that oncogenes may not only fuel the initiation of tumorigenesis, but in some cases must be excessively activated to maintain a neoplastic state [11]. Oncogene suppression acutely restores normal physiological programs that effectively overrides secondary genetic events and a cancer collapses [12,13]. Oncogene addiction is the description of the dramatic and sustained regression of some cancers upon the specific inactivation of a single oncogene [1-13,14(••),15,16(••)], that can occur through tumor intrinsic [1,2,4,12], but also host immune mechanisms [17-23]. Notably, oncogene inactivation elicits a host immune response that involves specific immune effectors and cytokines that facilitate a remodeling of the tumor microenvironment including the shut down of angiogenesis and the induction of cellular senescence of tumor cells [16(••)]. Hence, immune effectors are not only critically involved in tumor prevention, initiation [17-19], and progression [20], but also appear to be essential to tumor regression upon oncogene inactivation [21,22(••),23(••)]. Understanding how the inactivation of an oncogene elicits a systemic signal in the host that prompts a deconstruction of a tumor could have important implications. The combination of oncogene-targeted therapy together with immunomodulatory therapy may be ideal for the development of both robust tumor intrinsic and immunological responses, effectively leading to sustained tumor regression.

BRAF(V600) inhibitor GSK2118436 targeted inhibition of mutant BRAF in cancer patients does not impair overall immune competency

PURPOSE

An intact immune system likely contributes to the outcome of treatment and may be important for clearance of drug-resistant tumor cells and for prevention of recurrence. Although pharmacologic inhibition of BRAF(V600E) in melanoma patients, which is linked to immune suppression, results in an initial response rate, these responses are typically of limited duration. Combining immunotherapeutic drugs with kinase-targeted agents is an attractive strategy to increase clinical efficacy. Evidence suggesting that mitogen-activated protein kinase pathway activation in tumor cells contributes to immune suppression suggests that the two approaches may be synergistic, provided that BRAF(V600E) inhibitors are nontoxic to immune cells.

METHODS

To assess effects of mutant BRAF inhibition on systemic immunity, we studied 13 patients with tumors carrying a BRAF mutation who underwent treatment with GSK2118436, a V600 mutant BRAF-specific inhibitor. We carried out peripheral blood immunomonitoring before and following one or two 28-day cycles of treatment.

RESULTS

GSK2118436 treatment had no detectable impact on most immune parameters tested, including serum cytokine levels, peripheral blood cell counts, leukocyte subset frequencies, and memory CD4(+) and CD8(+) T-cell recall responses. A slight increase in serum TNF-α over the course of treatment was observed. In addition, three of the four human leukocyte antigen-A2-positive patients experienced a modest increase in circulating tumor antigen-specific CD8(+) T cells following BRAF(V600) inhibitor therapy.

CONCLUSIONS

GSK2118436 treatment results in no detectable negative impact on existing systemic immunity or the de novo generation of tumor-specific T cells. These findings suggest that future trials combining specific BRAF(V600E) inhibition with immunotherapy should not impair immune response.

Stem cells in liver diseases and cancer: recent advances on the path to new therapies

Stem cells have potential for therapy of liver diseases, but may also be involved in the formation of liver cancer. Recently, the American Association for the Study of Liver Diseases Henry M. and Lillian Stratton Basic Research Single Topic Conference "Stem Cells in Liver Diseases and Cancer: Discovery and Promise" brought together a diverse group of investigators to define the status of research on stem cells and cancer stem cells in the liver and identify problems and solutions on the path to clinical translation. This report summarizes the outcomes of the conference and provides an update on recent research advances. Progress in liver stem cell research includes isolation of primary liver progenitor cells (LPCs), directed hepatocyte differentiation of primary LPCs and pluripotent stem cells, findings of transdifferentiation, disease-specific considerations for establishing a therapeutically effective cell mass, and disease modeling in cell culture. Tumor-initiating stem-like cells (TISCs) that emerge during chronic liver injury share the expression of signaling pathways, including those organized around transforming growth factor beta and β-catenin, and surface markers with normal LPCs. Recent investigations of the role of TISCs in hepatocellular carcinoma have provided insight into the transcriptional and post-transcriptional regulation of hepatocarcinogenesis. Targeted chemotherapies for TISC are in development as a means to overcome cellular resistance and mechanisms driving disease progression in liver cancer.

Alternative Splicing of Fibroblast Growth Factor Receptor IgIII Loops in Cancer

Alternative splicing of the IgIII loop of fibroblast growth factor receptors (FGFRs) 1–3 produces b- and c-variants of the receptors with distinctly different biological impact based on their distinct ligand-binding spectrum. Tissue-specific expression of these splice variants regulates interactions in embryonic development, tissue maintenance and repair, and cancer. Alterations in FGFR2 splicing are involved in epithelial mesenchymal transition that produces invasive, metastatic features during tumor progression. Recent research has elucidated regulatory factors that determine the splice choice both on the level of exogenous signaling events and on the RNA-protein interaction level. Moreover, methodology has been developed that will enable the in depth analysis of splicing events during tumorigenesis and provide further insight on the role of FGFR 1–3 IIIb and IIIc in the pathophysiology of various malignancies. This paper aims to summarize expression patterns in various tumor types and outlines possibilities for further analysis and application.

TG02, a novel oral multi-kinase inhibitor of CDKs, JAK2 and FLT3 with potent anti-leukemic properties

TG02 is a novel pyrimidine-based multi-kinase inhibitor that inhibits CDKs 1, 2, 7 and 9 together with JAK2 and FLT3. It dose-dependently inhibits signaling pathways downstream of CDKs, JAK2 and FLT3 in cancer cells with the main targets being CDKs. TG02 is anti-proliferative in a broad range of tumor cell lines, inducing G1 cell cycle arrest and apoptosis. Primary cultures of progenitor cells derived from acute myeloid leukemia (AML) and polycythemia vera patients are very sensitive to TG02. Comparison with reference inhibitors that block only one of the main targets of TG02 demonstrate the benefit of combined CDK and JAK2/FLT3 inhibition in cell lines as well as primary cells. In vivo, TG02 exhibits favorable pharmacokinetics after oral dosing in xenograft models and accumulates in tumor tissues, inducing an effective blockade of both CDK and STAT signaling. TG02 induces tumor regression after oral dosing on both daily and intermittent schedules in a murine model of mutant-FLT3 leukemia (MV4-11) and prolongs survival in a disseminated AML model with wild-type FLT3 and JAK2 (HL-60). These data demonstrate that TG02 is active in various models of leukemia and provide a rationale for the ongoing clinical evaluation of TG02 in patients with advanced leukemias.