The immunomodulatory, antitumor and antimetastatic responses of melanoma-bearing normal and alcoholic mice to sunitinib and ALT-803: a combinatorial treatment approach

Enhancing CAR T cells function: role of immunomodulators in cancer immunotherapy

CAR T-cell therapy is a promising immunotherapy, providing successful results for cancer patients who are unresponsive to standard and traditional therapeutic approaches. However, there are limiting factors which create a hurdle in the therapy performing its role optimally. CAR T cells get exhausted, produce active antitumor responses, and might even produce toxic reactions. Specifically, in the case of solid tumors, chimeric antigen receptor T (CAR-T) cells fail to produce the desired outcomes. Then, the need to use supplementary agents such as immune system modifying immunomodulatory agents comes into play. A series of the literature was studied to evaluate the role of immunomodulators including a phytochemical, Food and Drug Administration (FDA)-approved targeted drugs, and ILs in support of their achievements in boosting the efficiency of CAR-T cell therapy. Some of the most promising out of them are reported in this article. It is expected that by using the right combinations of immunotherapy, immunomodulators, and traditional cancer treatments, the best possible cancer defying results may be produced in the future.

Mathematical modeling indicates that regulatory inhibition of CD8+ T cell cytotoxicity can limit efficacy of IL-15 immunotherapy in cases of high pre-treatment SIV viral load

Immunotherapeutic cytokines can activate immune cells against cancers and chronic infections. N-803 is an IL-15 superagonist that expands CD8+ T cells and increases their cytotoxicity. N-803 also temporarily reduced viral load in a limited subset of non-human primates infected with simian immunodeficiency virus (SIV), a model of HIV. However, viral suppression has not been observed in all SIV cohorts and may depend on pre-treatment viral load and the corresponding effects on CD8+ T cells. Starting from an existing mechanistic mathematical model of N-803 immunotherapy of SIV, we develop a model that includes activation of SIV-specific and non-SIV-specific CD8+ T cells by antigen, inflammation, and N-803. Also included is a regulatory counter-response that inhibits CD8+ T cell proliferation and function, representing the effects of immune checkpoint molecules and immunosuppressive cells. We simultaneously calibrate the model to two separate SIV cohorts. The first cohort had low viral loads prior to treatment (≈3-4 log viral RNA copy equivalents (CEQ)/mL), and N-803 treatment transiently suppressed viral load. The second had higher pre-treatment viral loads (≈5-7 log CEQ/mL) and saw no consistent virus suppression with N-803. The mathematical model can replicate the viral and CD8+ T cell dynamics of both cohorts based on different pre-treatment viral loads and different levels of regulatory inhibition of CD8+ T cells due to those viral loads (i.e. initial conditions of model). Our predictions are validated by additional data from these and other SIV cohorts. While both cohorts had high numbers of activated SIV-specific CD8+ T cells in simulations, viral suppression was precluded in the high viral load cohort due to elevated inhibition of cytotoxicity. Thus, we mathematically demonstrate how the pre-treatment viral load can influence immunotherapeutic efficacy, highlighting the in vivo conditions and combination therapies that could maximize efficacy and improve treatment outcomes.

Liposomal Co-delivery of PD-L1 siRNA/Anemoside B4 for Enhanced Combinational Immunotherapeutic Effect

Combination therapy has gained a lot of attention thanks to its superior activity against cancer. In the present study, we report a cRGD-targeted liposomal preparation for co-delivery of programmed cell death ligand 1 (PD-L1) small interfering RNA (siRNA) and anemoside B4 (AB4)─AB4/siP-c-L─and evaluate its anticancer efficiency in mouse models of LLC and 4T1 tumors. AB4/siP-c-L showed a particle size of (180.7 ± 7.3) nm and a ζ-potential of (32.8 ± 1.5) mV, with high drug encapsulation, pH-sensitive release properties, and good stability in serum. AB4/siP-c-L demonstrated prolonged blood circulation and increased tumor accumulation. Elevated cellular uptake was dependent on the targeting ligand cRGD. This combination induced significant tumor inhibition in LLC xenograft tumor-bearing mice by downregulating PD-L1 protein expression and modulating the immunosuppressive microenvironment. Liposomes favored the antitumor T-cell response with long-term memory, without obvious toxicity. A similar tumor growth inhibition was also demonstrated in the 4T1 tumor model. In summary, our results indicate that cRGD-modified and AB4- and PD-L1 siRNA-coloaded liposomes have potential as an antitumor preparation, and this approach may lay a foundation for the development of a new targeted drug delivery system.

Interleukins in the treatment of melanoma

Interleukins (ILs) and associated cytokines serve as the means of communication for immune cells and non-immune cells. The use of ILs in harnessing the immune system to cancer treatment has been a promising approach. ILs not only nurture an environment enabling cancer growth but also simultaneously trigger a productive tumor-directed immune response. These properties of ILs are increasingly being explored as a strategy to improve the outcomes of cancer. Here, we describe recently innovative technological approaches that have been developed to improve the pharmacokinetics, safety, and efficacies of IL-2, 15, 10, and 18 in the treatment of melanoma. Furthermore, the combination of ILs and immune checkpoint inhibition may synergize to reshape the tumor environment, thus yielding better clinical benefits in the future.

Safety, Tolerability, and Long-Term Clinical Outcomes of an IL-15 analogue (N-803) Admixed with Bacillus Calmette-Guérin (BCG) for the Treatment of Bladder Cancer

Intravesical BCG is active against non-muscle invasive bladder cancer (NMIBC), but bladder cancer will recur and even progress in a significant number of patients. To improve the response rate, N-803, an IL-15 superagonist was administered in combination with BCG. To evaluate the safety and efficacy associated with the use of intravesical N-803 and BCG in patients with BCG-naïve NMIBC. This phase 1b clinical trial used a 3 + 3 dose-escalation design. Participants were enrolled from July 2014 and July 2015, with follow-up and analyses through January 15, 2021. Eligibility criteria included histologically confirmed non-muscle invasive urothelial carcinoma of intermediate or high risk who had not received prior treatment with intravesical BCG (ie, BCG-naïve). All 9 participants met the eligibility criteria, received treatment according to the protocol, and were included in all analyses. Treatment was done once weekly for 6 consecutive weeks with bladder infusion of the standard dose of BCG, 50 mg/instillation, in combination with increasing doses of N-803 (100, 200, or 400 µg N-803 per instillation). No DLTs were noted in any of the dose cohorts. All adverse events (AEs) were manageable and less than grade 3. During the 2-year follow-up, all 9 participants were disease free. Furthermore, 6 y after treatment, all 9 participants (100%) were disease free with no evidence of disease progression and an intact bladder. This phase 1b trial found the combination of intravesical N-803 and BCG to be associated with modest toxic effects, low immunogenicity, and substantial prolonged antitumoral activity; phase 2 trials are in progress.

Immunomodulatory effects of cytokine-induced expansion of cytotoxic lymphocytes in a mouse model of lupus-like disease

BACKGROUND AIMS

Certain therapies (e.g., daclizumab) that promote expansion of natural killer (NK) cells are associated with clinical amelioration of disease in the context of multiple sclerosis and associated mouse models. The clinical benefits are putatively attributable to an enhanced capacity of NK cells to kill activated pathogenic T cells. Whether a parallel approach will also be effective in systemic lupus erythematosus (lupus), a multi-organ autoimmune disease driven by aberrant responses of self-reactive T and B cells, is unclear.

METHODS

In the present study, the authors assess the therapeutic impact of IL-2- and IL-15-based strategies for expanding NK cells on measures of lupus-like disease in a mouse model.

RESULTS

Unexpectedly, cytokine-mediated expansion of cytotoxic lymphocytes aggravated immunological measures of lupus-like disease. Depletion studies revealed that the negative effects of these cytokine-based regimens can largely be attributed to expansion of CD8 T cells rather than NK cells.

CONCLUSIONS

These results provoke caution in the use of cytokine-based therapeutics to treat co-morbid cancers in patients with lupus and highlight the need for new methods to selectively expand NK cells to further assess their clinical value in autoimmune disease.

Chimeric antigen receptor-T cell therapy for solid tumors require new clinical regimens

INTRODUCTION

Chimeric antigen receptor modified T cell (CAR-T) therapy has achieved encouraging breakthroughs in the treatment of hematological malignancies. Nevertheless, this success has not yet been extrapolated to solid tumors. This review focuses on new clinical regimens that could improve the therapeutic efficacy of CAR-T in solid tumors. Areas covered: Herein, the authors reviewed recent clinical trials using CAR-T therapies for the treatment of solid tumors. Specifically, this review covered the following areas: (1) the current status of CAR-T cells in the treatment of solid tumors; (2) the major factors constraining the efficacy of CAR-T cells in solid tumors; and (3) opinions regarding the future of CAR-T as a treatment for solid tumors. Expert commentary: While some recent studies have shown promising results, the ultimate success of CAR-T therapies in solid tumor patients will require the following improvements to clinical regimens: (1) local delivery of CAR-T cells; (2) combination of CAR-T cells with chemotherapeutic drugs to treat metastatic tumors; (3) combination of CAR-T with immune checkpoint inhibitors; (4) combination therapy using CAR-T cells targeting two different antigens; and (5) the use of CAR-T as a strategy to prevent tumor recurrence and metastasis after radical resection.

Chronic alcohol consumption inhibits peripheral NK cell development and maturation by decreasing the availability of IL-15

NK cells are innate immune cells and have important roles in antiviral and antitumor immunity. Based on the transcriptional regulation, organ distribution, and cell function, NK cells have recently been further divided into cytotoxic conventional NK cells (cNK) and noncytotoxic helper-like group 1 innate lymphoid cells (ILC1s). It is well known that chronic alcohol consumption decreases peripheral NK cell number and cytolytic activity; however, the underlying mechanism remains to be elucidated. How chronic alcohol consumption affects ILC1s is, to our knowledge, completely unexplored. Herein, we used a well-established mouse model of chronic alcohol consumption to study the effects of alcohol on transcription factor expression, maturation, and cytokine production of cNK cells and ILC1s in various organs. We found that alcohol consumption significantly decreased Eomes-expressing cNK cells in all the examined organs, except BM, but did not significantly affect ILC1s. Alcohol consumption compromised cNK cell development and maturation. Exogenous IL-15/IL-15Rα treatment caused full recovery of Eomes-expressing cNK cell number and maturation. Taken together, our data indicated that chronic alcohol consumption decreases cNK cell number and cytolytic activity by arresting cNK cell development at the CD27⁺CD11b⁺ stage. This developmental arrest of NK cells results from a lack of IL-15 availability in the microenvironment. IL-15/IL-15Rα treatment can recover alcohol consumption-induced developmental defect in NK cells.