Towards effective immunotherapy for lung cancer: simultaneous targeting of tumor-initiating cells and immune pathways in the tumor microenvironment

Nanoparticles overcome adaptive immune resistance and enhance immunotherapy via targeting tumor microenvironment in lung cancer

Lung cancer is one of the common malignant cancers worldwide. Immune checkpoint inhibitor (ICI) therapy has improved survival of lung cancer patients. However, ICI therapy leads to adaptive immune resistance and displays resistance to PD-1/PD-L1 blockade in lung cancer, leading to less immune response of lung cancer patients. Tumor microenvironment (TME) is an integral tumor microenvironment, which is involved in immunotherapy resistance. Nanomedicine has been used to enhance the immunotherapy in lung cancer. In this review article, we described the association between TME and immunotherapy in lung cancer. We also highlighted the importance of TME in immunotherapy in lung cancer. Moreover, we discussed how nanoparticles are involved in regulation of TME to improve the efficacy of immunotherapy, including Nanomedicine SGT-53, AZD1080, Nanomodulator NRF2, Cisplatin nanoparticles, Au@PG, DPAICP@ME, SPIO NP@M-P, NBTXR3 nanoparticles, ARAC nanoparticles, Nano-DOX, MS NPs, Nab-paclitaxel, GNPs-hPD-L1 siRNA. Furthermore, we concluded that targeting TME by nanoparticles could be helpful to overcome resistance to PD-1/PD-L1 blockade in lung cancer.

Tryptophan and Its Metabolites in Lung Cancer: Basic Functions and Clinical Significance

Lung cancer is the most lethal malignancy worldwide. Recently, it has been recognized that metabolic reprogramming is a complex and multifaceted factor, contributing to the process of lung cancer. Tryptophan (Try) is an essential amino acid, and Try and its metabolites can regulate the progression of lung cancer. Here, we review the pleiotropic functions of the Try metabolic pathway, its metabolites, and key enzymes in the pathogenic process of lung cancer, including modulating the tumor environment, promoting immune suppression, and drug resistance. We summarize the recent advance in therapeutic drugs targeting the Try metabolism and kynurenine pathway and their clinical trials.

The status of immunosuppression in patients with stage IIIB or IV non-small-cell lung cancer correlates with the clinical characteristics and response to chemotherapy

BACKGROUND

Indoleamine 2,3-dioxygenase (IDO) catalyzes the rate-limiting step of tryptophan (Trp) degradation via the kynurenine (Kyn) pathway, which inhibits the proliferation of T cells and induces the apoptosis of T cells, leading to immune tolerance. Therefore, IDO has been considered as the most important mechanism for tumor cells to escape from immune response. Previous studies suggested that IDO might be involved in the progression of tumor and resistance to chemotherapy. Several preclinical and clinical studies have proven that IDO inhibitors can regulate IDO-mediated tumor immune escape and potentiate the effect of chemotherapy. Thus, the present study investigated the correlation between the clinical parameters, responses to chemotherapy, and IDO activity to provide a theoretical basis for the clinical application of IDO inhibitors to improve the suppression status and poor prognosis in cancer patients.

METHODS

The serum concentrations of Trp and Kyn were measured by high-performance liquid chromatography in 252 patients with stage IIIB or IV non-small-cell lung cancer, and 55 healthy controls. The IDO activity was determined by calculating the serum Kyn-to-Trp (Kyn/Trp) ratio.

RESULTS

The IDO activity was significantly higher in the lung cancer patients than in the controls (median 0.0389 interquartile range [0.0178-0.0741] vs 0.0111 [0.0091-0.0133], respectively; P<0.0001). In addition, patients with adenocarcinoma had higher IDO activity than patients with nonadenocarcinoma (0.0449 [0.0189-0.0779] vs 0.0245 [0.0155-0.0563], respectively; P=0.006). Furthermore, patients with stage IIIB disease had higher IDO activity than patients with stage IV disease (0.0225 [0.0158-0.0595] vs 0.0445 [0.0190-0.0757], respectively; P=0.012). The most meaningful discovery was that there was a significant difference between the partial response (PR) patients and the stable disease (SD) and progressive disease (PD) patients (0.0240 [0.0155-0.0381] vs 0.0652 [0.0390-0.0831] vs 0.0868 [0.0209-0.0993], respectively, P<0.0001).

CONCLUSION

IDO activity was increased in lung cancer patients. Higher IDO activity correlated with histological types and disease stages of lung cancer patients, induced the cancer cells' resistance to chemotherapy, and decreased the efficacy of chemotherapy.

Novel antigens in non-small cell lung cancer: SP17, AKAP4, and PTTG1 are potential immunotherapeutic targets

Lung cancer is the leading cause of cancer deaths in both genders worldwide, with an incidence only second to prostate cancer in men and breast cancer in women. The lethality of the disease highlights the urgent need for innovative therapeutic options. Immunotherapy can afford efficient and specific targeting of tumor cells, improving efficacy and reducing the side effects of current therapies. We have previously reported the aberrant expression of cancer/testis antigens (CTAs) in tumors of unrelated histological origin. In this study we investigated the expression and immunogenicity of the CTAs, Sperm Protein 17 (SP17), A-kinase anchor protein 4 (AKAP4) and Pituitary Tumor Transforming Gene 1 (PTTG1) in human non-small cell lung cancer (NSCLC) cell lines and primary tumors. We found that SP17, AKAP4 and PTTG1 are aberrantly expressed in cancer samples, compared to normal lung cell lines and tissues. We established the immunogenicity of these CTAs by measuring CTA-specific autoantibodies in patients' sera and generating CTA-specific autologous cytotoxic lymphocytes from patients' peripheral blood mononuclear cells. Our results provide proof of principle that the CTAs SP17/AKAP4/PTTG1 are expressed in both human NSCLC cell lines and primary tumors and can elicit an immunogenic response in lung cancer patients.

Utility of kynurenic acid for non-invasive detection of metastatic spread to lymph nodes in non-small cell lung cancer

BACKGROUND

Kynurenic acid (KYNA) is a side-stream product of the kynurenine metabolic pathway that plays a controversial role in malignancies either enabling escape of malignant cells from immune surveillance or exerting antiproliferative effect on cancer cells, and is associated with differences in invasiveness related to metastatic spread to lymph nodes in lung cancer. Nodal involvement is a significant negative prognostic factor usually considered a contraindication for primary surgical resection.

OBJECTIVE

To assess potential value of circulating KYNA for non-invasive identification of patients with metastatic lymph nodes (N+) in non-small cell lung cancer (NSCLC).

METHODS

KYNA level in venous blood serum was determined with use of high performance liquid chromatography (HPLC) in 312 subjects including 230 patients with NSCLC and 32 healthy controls.

RESULTS

Circulating KYNA level in NSCLC patients was higher than in controls (93.6±61.9 pmol/ml vs. 31.4±16.6 pmol/ml; p=2.2•10(-15)) and positively correlated with N (R=0.326; p=2•(10-6)) but not with T or M stage (p>0.05). In N+ patients it was higher than in N0 patients (137.7±51.8 pmol/ml vs. 71.9±41.7 pmol/ml; p=4.8•10(-16)). KYNA effectively discriminated N+ from N0 patients at a cut-off value 82.3 pmol/ml with sensitivity 94.7% (95%CI 87.1-98.5%), specificity 80.5% (95%CI 73.4-86.5%), negative predictive value NPV=96.8%, PPV=70.5% and area under the ROC curve AUC=0.900 (95%CI 0.854-0.935; p=0.0001).

DISCUSSION AND CONCLUSION

Circulating KYNA level measurement offers reliable non-invasive discrimination between N0 and N+ patients in NSCLC. Robust discriminatory characteristics of KYNA assay predestines it for clinical use as an adjunct facilitating selection of candidates for primary surgical resection.

Vaccines in non-small cell lung cancer: rationale, combination strategies and update on clinical trials

Non-small cell lung cancer (NSCLC) remains the leading cause of cancer related mortality worldwide and despite some advances in therapy the overall prognosis remains disappointing. New therapeutic approaches like vaccination have been proposed and several clinical trials are ongoing. Many tumor antigens have been identified so far and specific tumor vaccines targeting these antigens have been developed. Even if the ideal setting for vaccine therapy might be the adjuvant one, vaccines seem to be potentially beneficial also in advanced disease and combination therapy could be a promising treatment option. In the advanced setting anti-MUC-1 vaccine (belagenpumatucel) and anti-TGF-β(2) vaccine (BPL-25) have entered in phase III trials as maintenance therapy after first line chemotherapy. In the adjuvant setting the most relevant and promising vaccines are directed against MAGE-A3 and PRAME, respectively. We will review the key points for effective active immunotherapies and combination therapies, giving an update on the most promising vaccines developed in NSCLC.

Vaccines targeting tumor blood vessel antigens promote CD8(+) T cell-dependent tumor eradication or dormancy in HLA-A2 transgenic mice

We have recently shown that effective cytokine gene therapy of solid tumors in HLA-A2 transgenic (HHD) mice lacking murine MHC class I molecule expression results in the generation of HLA-A2-restricted CD8(+) T effector cells selectively recognizing tumor blood vessel-associated pericytes and/or vascular endothelial cells. Using an HHD model in which HLA-A2(neg) tumor (MC38 colon carcinoma or B16 melanoma) cells are not recognized by the CD8(+) T cell repertoire, we now show that vaccines on the basis of tumor-associated blood vessel Ags (TBVA) elicit protective Tc1-dependent immunity capable of mediating tumor regression or extending overall survival. Vaccine efficacy was not observed if (HLA-A2(neg)) wild-type C57BL/6 mice were instead used as recipient animals. In the HHD model, effective vaccination resulted in profound infiltration of tumor lesions by CD8(+) (but not CD4(+)) T cells, in a coordinate reduction of CD31(+) blood vessels in the tumor microenvironment, and in the "spreading" of CD8(+) T cell responses to alternate TBVA that were not intrinsic to the vaccine. Protective Tc1-mediated immunity was durable and directly recognized pericytes and/or vascular endothelial cells flow-sorted from tumor tissue but not from tumor-uninvolved normal kidneys harvested from these same animals. Strikingly, the depletion of CD8(+), but not CD4(+), T cells at late time points after effective therapy frequently resulted in the recurrence of disease at the site of the regressed primary lesion. This suggests that the vaccine-induced anti-TBVA T cell repertoire can mediate the clinically preferred outcomes of either effectively eradicating tumors or policing a state of (occult) tumor dormancy.