A new biosensor was engineered to visualize Lck kinase preactivation and regulation in live T cells.

Chimeric antigen receptor (CAR) T cell therapy, as an innovative immunotherapy, plays a huge role in current cancer therapy. Although CAR T cell therapy has demonstrated therapeutic effects in some subtypes of B cell leukemia or lymphoma, there are many challenges that limit the therapeutic efficacy of CAR T cells in solid tumors. And how to efficiently transport CAR T cells to tumor tissues is a continuing concern for us. In this review, experiments have been extensively studied and compared. We finally compared the influence of different injection methods on therapeutic efficacy. We also carefully explored the difficulties of designing, homing, and working of CAR T cells, and ultimately came up with better solutions for each process to help CAR T cells reach tumor tissue more efficiently and quickly. These results will have significant implications for guiding CAR T cell therapy in cancer treatment.

Chimeric antigen receptor (CAR) T cells have been successfully used for hematological malignancies, especially for relapsed/refractory B-cell acute lymphoblastic leukemia and non-Hodgkin’s lymphoma. Patients who have undergone conventional chemo-immunotherapy and have relapsed can achieve complete remission for several months with the infusion of CAR T-cells. However, side effects and short duration of response are still major barriers to further CAR T-cell therapy. To improve the efficacy, multiple targets, the discovery of new target antigens, and CAR T-cell optimization have been extensively studied. Nevertheless, the fact that the determination of the efficacy of CAR T-cell therapy is inseparable from the discussion of clinical application strategies has rarely been discussed. In this review, we will discuss some clinical application strategies, including lymphodepletion regimens, dosing strategies, combination treatment, and side effect management, which are closely related to augmenting and maximizing the efficacy of CAR T-cell therapy.

The proliferation of CAR‐T cells was hindered and cannot play its killing function well in solid tumors. And yet the regulatory mechanism of CAR‐T cell proliferation is not fully understood. Here, we showed that recombinant expression of CD19CAR in T cells significantly increased the basal activation level of CAR‐T cells and LCK activation. Both LCK and SMAD4 were essential for CAR‐T cells proliferation since over‐express LCK or SMAD4 significantly promotes CAR‐T cells proliferation, while knock‐down LCK or SMAD4 expression inhibited the proliferation of CAR‐T cells seriously. More cells go into apoptosis when knock‐down LCK or SMAD4 expression, and the cell cycle was arrested in G2/M or S phase, respectively. Over‐express LCK or SMAD4 significantly promotes phosphorylation of PI3K and Akt, while it was inhibited when cells were treated with PI3K and Akt inhibitors (LY294002 or MK2206). Further mechanism exploration experiments showed that SMAD4 bound on the promoter region of LCK regulating its expression. Taken together, we reported that the transcription factor SMAD4 regulated the expression of LCK and further involved in the PI3K/Akt signaling pathway to affect the proliferation of CAR‐T cells.