Salt-inducible kinase 3 protects tumor cells from cytotoxic T-cell attack by promoting TNF-induced NF-κB activation.

Background: Cancer immunotherapeutic strategies showed unprecedented results in the clinic. However, many patients do not respond to immuno-oncological treatments due to the occurrence of a plethora of immunological obstacles, including tumor intrinsic mechanisms of resistance to cytotoxic T-cell (TC) attack. Thus, a deeper understanding of these mechanisms is needed to develop successful immunotherapies.

Common clonal origin of conventional T cells and induced regulatory T cells in breast cancer patients.

Regulatory CD4 T cells (Treg) prevent tumor clearance by conventional T cells (Tconv) comprising a major obstacle of cancer immune-surveillance. Hitherto, the mechanisms of Treg repertoire formation in human cancers remain largely unclear. Here, we analyze Treg clonal origin in breast cancer patients using T-Cell Receptor and single-cell transcriptome sequencing.

CAMK1D Triggers Immune Resistance of Human Tumor Cells Refractory to Anti-PD-L1 Treatment.

The success of cancer immunotherapy is limited by resistance to immune checkpoint blockade. We therefore conducted a genetic screen to identify genes that mediated resistance against CTLs in anti-PD-L1 treatment-refractory human tumors. Using PD-L1-positive multiple myeloma cells cocultured with tumor-reactive bone marrow-infiltrating CTL as a model, we identified calcium/calmodulin-dependent protein kinase 1D (CAMK1D) as a key modulator of tumor-intrinsic immune resistance.

A high-throughput RNAi screen for detection of immune-checkpoint molecules that mediate tumor resistance to cytotoxic T lymphocytes.

The success of T cell-based cancer immunotherapy is limited by tumor's resistance against killing by cytotoxic T lymphocytes (CTLs). Tumor-immune resistance is mediated by cell surface ligands that engage immune-inhibitory receptors on T cells. These ligands represent potent targets for therapeutic inhibition.

Antitumor effect of paclitaxel is mediated by inhibition of myeloid-derived suppressor cells and chronic inflammation in the spontaneous melanoma model.

The antitumor effects of paclitaxel are generally attributed to the suppression of microtubule dynamics resulting in defects in cell division. New data demonstrated that in ultralow noncytotoxic concentrations, paclitaxel modulated in immune cells in vitro the activity of small Rho GTPases, the key regulators of intracellular actin dynamics. However, the immunomodulatory properties of paclitaxel in vivo have not been evaluated.

Cyclophosphamide promotes chronic inflammation-dependent immunosuppression and prevents antitumor response in melanoma.

Low-dose cyclophosphamide (CP) therapy induces immunogenic tumor cell death and decreases regulatory T cell (Treg) numbers in mice with transplantable tumors. Using the ret transgenic murine melanoma model that resembles human melanoma, we detected no beneficial antitumor effects with such treatment, despite a decrease in Tregs. On the contrary, low-dose CP enhanced the production of chronic inflammatory mediators in melanoma lesions associated with increased accumulation of Gr1(+)CD11b(+) myeloid-derived suppressor cells (MDSCs), which exhibit elevated suppressive activity and nitric oxide (NO) production as well as inhibition of T-cell proliferation.

Acid-mediated prevention of aspartimide formation in solid phase peptide synthesis.

Aspartimide formation is one of the major obstacles that impedes the solid phase synthesis of large peptides and proteins. Until now, no cost-effective strategy to suppress this side reaction has been developed. Here it is demonstrated that addition of small amounts of organic acids to the standard Fmoc cleavage agent piperidine efficiently prevents formation of aspartimide side products.

Paclitaxel promotes differentiation of myeloid-derived suppressor cells into dendritic cells in vitro in a TLR4-independent manner.

Myeloid cells play a key role in the outcome of anti-tumor immunity and response to anti-cancer therapy, since in the tumor microenvironment they may exert both stimulatory and inhibitory pressures on the proliferative, angiogenic, metastatic, and immunomodulating potential of tumor cells. Therefore, understanding the mechanisms of myeloid regulatory cell differentiation is critical for developing strategies for the therapeutic reversal of myeloid derived suppressor cell (MDSC) accumulation in the tumor-bearing hosts. Here, using an in vitro model system, several potential mechanisms of the direct effect of paclitaxel on MDSC were tested, which might be responsible for the anti-tumor potential of low-dose paclitaxel therapy in mice.