Mechanisms of action of tasquinimod on the tumour microenvironment

Role of S100 Proteins in Colorectal Carcinogenesis

The family of S100 proteins represents 25 relatively small (9-13 kD) calcium binding proteins. These proteins possess a broad spectrum of important intracellular and extracellular functions. Colorectal cancer is the third most common cancer in men (after lung and prostate cancer) and the second most frequent cancer in women (after breast cancer) worldwide. S100 proteins are involved in the colorectal carcinogenesis through different mechanisms: they enable proliferation, invasion, and migration of the tumour cells; furthermore, S100 proteins increase angiogenesis and activate NF-κβ signaling pathway, which plays a key role in the molecular pathogenesis especially of colitis-associated carcinoma. The expression of S100 proteins in the cancerous tissue and serum levels of S100 proteins might be used as a precise diagnostic and prognostic marker in patients with suspected or already diagnosed colorectal neoplasia. Possibly, in the future, S100 proteins will be a therapeutic target for tailored anticancer therapy.

Metastatic castration-resistant prostate cancer: time for innovation

Androgen deprivation is the mainstay of advanced prostate cancer treatment. Despite initial responses, almost all patients progress to castration-resistant prostate cancer (CRPC). The understanding of the biology of CRPC and the evidence that CRPC still remains driven by androgen receptor signaling led to the discovery of new therapeutic targets. In the last few years, large Phase III trials showed improvements in survival and outcomes and led to the approval of a CYP17 inhibitor (abiraterone), an androgen receptor antagonist (enzalutamide), the taxane cabazitaxel, an α-emitter (radium-223), the bone resorption-targeting drug denosumab and an immunotherapy (sipuleucel-T). This article describes the molecular mechanisms underlying castration resistance, discusses recent and ongoing trials and offers some insights into identifying the best sequence of new drugs.

[New therapies in metastatic castration resistant prostate cancer]

Therapeutic arsenal in prostate cancer widens for several years. New hormonal therapies such as acetate abiraterone or enzalutamide were the first molecules to revolutionize the treatment of metastatic castration resistant prostate cancer. Several other treatments are on trial targeting different pathways: androgene pathway (TAK-007, ARN-509, ODM-201, TOK-001), immune system (sipuleucel, ipilimumab, PROSTVAC-V/F, tasquinimod), but also tumor cell (PARP inhibitor, cabozantinib). The treatment sequencing will therefore soon be problematic, raising the necessity to identify predictive markers of response to the new therapies.

[Tasquinimod: How to act on microenvironment in metastatic prostate cancer]

Despite the recent introduction of new drugs, castration-resistant metastatic prostate cancer, (mCRPC) remains a poor prognosis disease, with a crucial need for new therapeutic approaches. Tasquinimod is a newly developed molecule, orally administered, currently evaluated in phase III studies. Tasquinimod targets the tumor microenvironment, focusing on the angiogenic and immune components. Its specific action on the S100A9 protein restores immunity and reduces angiogenesis. A phase II double-blind randomized study against placebo showed an improvement of more than 50% of progression free survival in the group of mCRPC patients treated with tasquinimod, as compared to the placebo group. At a dose of 1mg/day, the tolerance of tasquinimod appeared acceptable. This review presents the available preclinical and clinical results of tasquinimod, with a particular focus on the originality of its mode of action.

Trial watch: Dendritic cell-based anticancer therapy

The use of patient-derived dendritic cells (DCs) as a means to elicit therapeutically relevant immune responses in cancer patients has been extensively investigated throughout the past decade. In this context, DCs are generally expanded, exposed to autologous tumor cell lysates or loaded with specific tumor-associated antigens (TAAs), and then reintroduced into patients, often in combination with one or more immunostimulatory agents. As an alternative, TAAs are targeted to DCs in vivo by means of monoclonal antibodies, carbohydrate moieties or viral vectors specific for DC receptors. All these approaches have been shown to (re)activate tumor-specific immune responses in mice, often mediating robust therapeutic effects. In 2010, the first DC-based preparation (sipuleucel-T, also known as Provenge®) has been approved by the US Food and Drug Administration (FDA) for use in humans. Reflecting the central position occupied by DCs in the regulation of immunological tolerance and adaptive immunity, the interest in harnessing them for the development of novel immunotherapeutic anticancer regimens remains high. Here, we summarize recent advances in the preclinical and clinical development of DC-based anticancer therapeutics.

Myeloid-derived suppressor cells as therapeutic target in hematological malignancies

Myeloid-derived suppressor cells (MDSC) are a heterogeneous population of immature myeloid cells that accumulate during pathological conditions such as cancer and are associated with a poor clinical outcome. MDSC expansion hampers the host anti-tumor immune response by inhibition of T cell proliferation, cytokine secretion, and recruitment of regulatory T cells. In addition, MDSC exert non-immunological functions including the promotion of angiogenesis, tumor invasion, and metastasis. Recent years, MDSC are considered as a potential target in solid tumors and hematological malignancies to enhance the effects of currently used immune modulating agents. This review focuses on the characteristics, distribution, functions, cell–cell interactions, and targeting of MDSC in hematological malignancies including multiple myeloma, lymphoma, and leukemia.

Tasquinimod modulates suppressive myeloid cells and enhances cancer immunotherapies in murine models

A major barrier for cancer immunotherapy is the presence of suppressive cell populations in patients with cancer, such as myeloid-derived suppressor cells (MDSC) and tumor-associated macrophages (TAM), which contribute to the immunosuppressive microenvironment that promotes tumor growth and metastasis. Tasquinimod is a novel antitumor agent that is currently at an advanced stage of clinical development for treatment of castration-resistant prostate cancer. A target of tasquinimod is the inflammatory protein S100A9, which has been demonstrated to affect the accumulation and function of tumor-suppressive myeloid cells. Here, we report that tasquinimod provided a significant enhancement to the antitumor effects of two different immunotherapeutics in mouse models of cancer: a tumor vaccine (SurVaxM) for prostate cancer and a tumor-targeted superantigen (TTS) for melanoma. In the combination strategies, tasquinimod inhibited distinct MDSC populations and TAMs of the M2-polarized phenotype (CD206(+)). CD11b(+) myeloid cells isolated from tumors of treated mice expressed lower levels of arginase-1 and higher levels of inducible nitric oxide synthase (iNOS), and were less immunosuppressive ex vivo, which translated into a significantly reduced tumor-promoting capacity in vivo when these cells were coinjected with tumor cells. Tumor-specific CD8(+) T cells were increased markedly in the circulation and in tumors. Furthermore, T-cell effector functions, including cell-mediated cytotoxicity and IFNγ production, were potentiated. Taken together, these data suggest that pharmacologic targeting of suppressive myeloid cells by tasquinimod induces therapeutic benefit and provide the rationale for clinical testing of tasquinimod in combination with cancer immunotherapies.

Quantitative determination of the anti-tumor agent tasquinimod in human urine by liquid chromatography-tandem mass spectrometry

Tasquinimod is an anti-tumor drug that is currently in clinical development for the treatment of solid cancers. After oral administration, tasquinimod and a number of its metabolites are excreted in the urine. The quantitative determination of tasquinimod in urine is challenging because of the required sensitivity (down to 0.1nM or 40pg/mL), the highly variable nature of this biological matrix and the presence of potentially unstable metabolites, which may convert back to the parent drug. In this article, an LC-MS/MS method is described for the determination of tasquinimod in human urine in the concentration range 0.1-200nM. Liquid-liquid extraction with n-chlorobutane was used to extract tasquinimod from 100μL human urine and to remove interfering endogenous urinary constituents. Reversed-phase liquid chromatography coupled to a triple quadrupole mass spectrometer equipped with an ESI source was used for quantification of tasquinimod in a 2.5-min run. A stable-isotope labeled internal standard was used for response normalization. The intra- and inter-day coefficients of variation (precision) as well as the bias (accuracy) of the method were below 7%. Although considerable conversion of conjugated tasquinimod metabolites back to parent drug was observed when incurred samples were stored at 37°C for a prolonged time, tasquinimod as well as its metabolites were sufficiently stable under all relevant sampling, storage and analysis conditions. The method was successfully applied to determine the urinary excretion of tasquinimod in healthy volunteers and patients with renal impairment after a 0.5-mg oral dose.

Biotensegrity of the extracellular matrix: physiology, dynamic mechanical balance, and implications in oncology and mechanotherapy

Cells have the capacity to convert mechanical stimuli into chemical changes. This process is based on the tensegrity principle, a mechanism of tensional integrity. To date, this principle has been demonstrated to act in physiological processes such as mechanotransduction and mechanosensing at different scales (from cell sensing through integrins to molecular mechanical interventions or even localized massage). The process involves intra- and extracellular components, including the participation of extracellular matrix (ECM) and microtubules that act as compression structures, and actin filaments which act as tension structures. The nucleus itself has its own tensegrity system which is implicated in cell proliferation, differentiation, and apoptosis. Despite present advances, only the tip of the iceberg has so far been uncovered regarding the role of ECM compounds in influencing biotensegrity in pathological processes. Groups of cells, together with the surrounding ground substance, are subject to different and specific forces that certainly influence biological processes. In this paper, we review the current knowledge on the role of ECM elements in determining biotensegrity in malignant processes and describe their implication in therapeutic response, resistance to chemo- and radiotherapy, and subsequent tumor progression. Original data based on the study of neuroblastic tumors will be provided.