Perspectives in immunotherapy: meeting report from the "Immunotherapy Bridge 2018" (28-29 November, 2018, Naples, Italy)

TRP Family Genes Are Differently Expressed and Correlated with Immune Response in Glioma

(1) Background: glioma is the most prevalent primary tumor of the human central nervous system and accompanies extremely poor prognosis in patients. The transient receptor potential (TRP) channels family consists of six different families, which are closely associated with cancer cell proliferation, differentiation, migration, and invasion. TRP family genes play an essential role in the development of tumors. Nevertheless, the function of these genes in gliomas is not fully understood. (2) Methods: we analyze the gene expression data of 28 TRP family genes in glioma patients through bioinformatic analysis. (3) Results: the study showed the aberrations of TRP family genes were correlated to prognosis in glioma. Then, we set enrichment analysis and selected 10 hub genes that may play an important role in glioma. Meanwhile, the expression of 10 hub genes was further established according to different grades, survival time, IDH mutation status, and 1p/19q codeletion status. We found that TRPC1, TRPC3, TRPC4, TRPC5, TRPC6, MCOLN1, MCOLN2, and MCOLN3 were significantly correlated to the prognosis in glioma patients. Furthermore, we illustrated that the expression of hub genes was associated with immune activation and immunoregulators (immunoinhibitors, immunostimulators, and MHC molecules) in glioma. (4) Conclusions: we proved that TRP family genes are promising immunotherapeutic targets and potential clinical biomarkers in patients with glioma.

Development and Validation of Lactate Metabolism-Related lncRNA Signature as a Prognostic Model for Lung Adenocarcinoma

BACKGROUND

Lung cancer has been a prominent research focus in recent years due to its role in cancer-related fatalities globally, with lung adenocarcinoma (LUAD) being the most prevalent histological form. Nonetheless, no signature of lactate metabolism-related long non-coding RNAs (LMR-lncRNAs) has been developed for patients with LUAD. Accordingly, we aimed to develop a unique LMR-lncRNA signature to determine the prognosis of patients with LUAD.

METHOD

The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases were utilized to derive the lncRNA expression patterns. Identification of LMR-lncRNAs was accomplished by analyzing the co-expression patterns between lncRNAs and LMR genes. Subsequently, the association between lncRNA levels and survival outcomes was determined to develop an effective signature. In the TCGA cohort, Cox regression was enlisted to build an innovative signature consisting of three LMR-lncRNAs, which was validated in the GEO validation cohort. GSEA and immune infiltration analysis were conducted to investigate the functional annotation of the signature and the function of each type of immune cell.

RESULTS

Fourteen differentially expressed LMR-lncRNAs were strongly correlated with the prognosis of patients with LUAD and collectively formed a new LMR-lncRNA signature. The patients could be categorized into two cohorts based on their LMR-lncRNA signatures: a low-risk and high-risk group. The overall survival of patients with LUAD in the high-risk group was considerably lower than those in the low-risk group. Using Cox regression, this signature was shown to have substantial potential as an independent prognostic factor, which was further confirmed in the GEO cohort. Moreover, the signature could anticipate survival across different groups based on stage, age, and gender, among other variables. This signature also correlated with immune cell infiltration (including B cells, neutrophils, CD4⁺ T cells, CD8⁺ T cells, etc.) as well as the immune checkpoint blockade target CTLA-4.

CONCLUSION

We developed and verified a new LMR-lncRNA signature useful for anticipating the survival of patients with LUAD. This signature could give potentially critical insight for immunotherapy interventions in patients with LUAD.

Immune Checkpoint Inhibitors Regulate K+ Channel Activity in Cytotoxic T Lymphocytes of Head and Neck Cancer Patients

Programmed death receptor-1 (PD-1) and its ligand (PD-L1) interaction negatively regulates T cell function in head and neck squamous cell carcinoma (HNSCC). Overexpression of PD-1 reduces intracellular Ca²⁺ fluxes, and thereby T cell effector functions. In HNSCC patients, PD-1 blockade increases KCa3.1 and Kv1.3 activity along with Ca²⁺ signaling and mobility in CD8⁺ peripheral blood T cells (PBTs). The mechanism by which PD-L1/PD-1 interaction regulates ion channel function is not known. We investigated the effects of blocking PD-1 and PD-L1 on ion channel functions and intracellular Ca²⁺ signaling in CD8⁺ PBTs of HNSCC patients and healthy donors (HDs) using single-cell electrophysiology and live microscopy. Anti-PD-1 and anti-PD-L1 antibodies increase KCa3.1 and Kv1.3 function in CD8⁺ PBTs of HNSCC patients. Anti-PD-1 treatment increases Ca²⁺ fluxes in a subset of HSNCC patients. In CD8⁺ PBTs of HDs, exposure to PD-L1 reduces KCa3.1 activity and Ca²⁺ signaling, which were restored by anti-PD-1 treatment. The PD-L1-induced inhibition of KCa3.1 channels was rescued by the intracellular application of the PI3 kinase modulator phosphatidylinositol 3-phosphate (PI3P) in patch-clamp experiments. In HNSCC CD8⁺ PBTs, anti-PD-1 treatment did not affect the expression of KCa3.1, Kv1.3, Ca²⁺ release activated Ca²⁺ (CRAC) channels, and markers of cell activation (CD69) and exhaustion (LAG-3 and TIM-3). Our data show that immune checkpoint blockade improves T cell function by increasing KCa3.1 and Kv1.3 channel activity in HNSCC patients.

Dr Effects of Adiponectin, Plasma D-Dimer, Inflammation and Tumor Markers on Clinical Characteristics and Prognosis of Patients with Ovarian Cancer

 [Abstract] Objective: To investigate the effects of adiponectin (ADPN), plasma D-dimer (D-D), inflammation and tumor markers on clinical characteristics and prognosis of patients with ovarian cancer. Methods: A total of 80 patients with ovarian cancer treated in our hospital from April 2017 to November 2019 were enrolled as study subjects and evenly divided into observation group (patients with ovarian cancer) and control group (patients with benign ovarian tumor) based on the results of postoperative pathological biopsy. The levels of ADPN, plasma D-D, inflammatory factors and serum tumor markers [carbohydrate antigen 125 (CA125), human epididymis protein 4 (HE4) and risk of ovarian malignancy algorithm (ROMA)] were compared between the two groups. The diagnostic value of serum tumor markers CA125, HE4 and ROMA in ovarian cancer was explored. The correlations of the changes of ROMA with the changes in the levels of ADPN, plasma D-D, high-sensitivity C-reactive protein (hs-CRP), CA125 and HE4 were analyzed. Additionally, the related risk factors affecting the development of ovarian cancer were subjected to univariate and multivariate logistic regression analyses. Results: In comparison with control group, observation group exhibited a lowered ADPN level (p<0.05), notably raised levels of plasma D-D, inflammatory factors hs-CRP and interleukin-6 (IL-6) and serum tumor markers CA125 and HE4 and an evidently increased ROMA (p<0.05). Besides, the detection of serum ROMA showed the highest specificity and sensitivity and low false positive rate and false negative rate. The changes of ROMA were positively correlated with the changes in the levels of plasma D-D, hs-CRP, CA125 and HE4 (p<0.05), and negatively associated with the changes in ADPN level (p<0.05). The results of univariate analysis showed that abnormal ADPN, D-D, hs-CRP, IL-6, CA125 and HE4 levels were related risk factors affecting the development of ovarian cancer. It was found through multivariate logistic regression analysis that decreased ADPN level and increased D-D, hs-CRP, IL-6, CA125 and HE4 levels were independent risk factors affecting the development of ovarian cancer. Conclusion: In the case of ovarian cancer, the ADPN level declines, while the levels of plasma D-D, inflammatory factors, and serum tumor markers CA125, HE4 and ROMA rise obviously. Besides, the ROMA level displays a positive relation to the content of CA125, HE4, plasma D-D and inflammatory factors and a negative association with ADPN level.

The diterpenoid adenanthin upregulates the expression of natural killer group 2D receptor ligands in hepatocellular carcinoma cells

OBJECTIVE

The natural killer (NK) group 2D (NKG2D) receptor plays a crucial role in NK cell-mediated anti-tumor immunity. NKG2D anti-proliferative effect is mediated by direct interactions of the receptor with its ligands that may be considered as a potential target for NK-based immunotherapeutic strategy in cancer cells.

METHODS

Here we report that a natural product adenanthin significantly promotes NKG2D ligands expression in hepatoma cells. The effect was determined using flow cytometry analysis. The activity of NK cell was evaluated by measuring its degranulation activity and cytotoxicity.

RESULTS

Our data indicates that the induction of NKG2D ligand binding to liver cancer cell surface receptors greatly improves the killing activity of NK cells against the cancer cells.

CONCLUSIONS

This is the first report of a new mechanism anti-cancer effects of adenanthin mediated by an indirect activation of NK cells. Our data suggests that adenanthin may be used to sensitize NK cells in tumor immunotherapy.

Cancer Stem Cells and the Slow Cycling Phenotype: How to Cut the Gordian Knot Driving Resistance to Therapy in Melanoma

Simple Summary

Cancer stem cells play a central role in the development of cancer and are poorly sensitive to standard chemotherapy and radiotherapy. Furthermore, they are also responsible for the onset of drug resistance. This also occurs in malignant melanoma, the deadliest form of skin cancer. Hence, cancer stem cells eradication is one of the main challenges for medical oncology. Here, we conducted a bioinformatics approach aimed to identify the main circuits and proteins underpinning cancer stem cell fitness in melanoma. Several lessons emerged from our work and may help to conceptualize future therapeutic approaches to prolong the efficacy of current therapies.

Abstract

Cancer stem cells (CSCs) have historically been defined as slow cycling elements that are able to differentiate into mature cells but without dedifferentiation in the opposite direction. Thanks to advances in genomic and non-genomic technologies, the CSC theory has more recently been reconsidered in a dynamic manner according to a “phenotype switching” plastic model. Transcriptional reprogramming rewires this plasticity and enables heterogeneous tumors to influence cancer progression and to adapt themselves to drug exposure by selecting a subpopulation of slow cycling cells, similar in nature to the originally defined CSCs. This model has been conceptualized for malignant melanoma tailored to explain resistance to target therapies. Here, we conducted a bioinformatics analysis of available data directed to the identification of the molecular pathways sustaining slow cycling melanoma stem cells. Using this approach, we identified a signature of 25 genes that were assigned to four major clusters, namely (1) kinases and metabolic changes, (2) melanoma-associated proteins, (3) Hippo pathway and (4) slow cycling/CSCs factors. Furthermore, we show how a protein−protein interaction network may be the main driver of these melanoma cell subpopulations. Finally, mining The Cancer Genome Atlas (TCGA) data we evaluated the expression levels of this signature in the four melanoma mutational subtypes. The concomitant alteration of these genes correlates with the worst overall survival (OS) for melanoma patients harboring BRAF-mutations. All together these results underscore the potentiality to target this signature to selectively kill CSCs and to achieve disease control in melanoma.

Local and distant tumor dormancy during early stage breast cancer are associated with the predominance of infiltrating T effector subsets

Background

Although breast cancer mortality is a result of distant recurrences associated with the establishment of tumor dormancy, current clinical practice guidelines recommend a wait and watch approach for tumor recurrences. This is because of our limited understanding of tumor dormancy and insufficient evidence in support of immunological control of tumor dormancy.

Methods

We used FVBN202 transgenic mice expressing rat neu oncogene in the mammary glands, and their parental FVB strain lacking neu expression. These models allowed the detection of tumor dormancy at distant sites using the rat neu protein as a tumor marker. We also used Ki67 for the detection of the indolent and quiescent types of tumor dormancy. Multicolor flow cytometry was used to detect dormant tumor cells and T cell subsets. Co-culture studies were performed to determine the role of T cells in preventing regrowth of dormant cells.

Results

We demonstrated that dormant tumor cells were present at the site of primary breast cancer and at distant sites in the lungs and in the liver very early in the course of early stage breast cancer when no distant metastasis was evident. Dormant tumor cells were characterized as neu expressing Ki67⁻ and Ki67^low fractions associated with the induction of local immune responses predominated by CD4+ and CD8+ T effector cell subsets. The presence of neu-autoreactive T cells from FVBN202 mice only prevented regrowth of dormant cells. On the other hand, presence of neu-alloreactive anti-tumor T cells in FVB mice prior to tumor challenge resulted in the protection of mice from the dissemination of dormant tumor cells to distant organs.

Conclusion

Our results suggest that immunotherapeutic targeting of semi-allogeneic mutant neoantigens during tumor dormancy might prevent distant recurrence of the disease.

Identification of a Prognostic Model Based on Immune-Related Genes of Lung Squamous Cell Carcinoma

Immune-related genes (IRGs) play considerable roles in tumor immune microenvironment (IME). This research aimed to discover the differentially expressed immune-related genes (DEIRGs) based on the Cox predictive model to predict survival for lung squamous cell carcinoma (LUSC) through bioinformatics analysis. First of all, the differentially expressed genes (DEGs) were acquired based on The Cancer Genome Atlas (TCGA) using the limma R package, the DEIRGs were obtained from the ImmPort database, whereas the differentially expressed transcription factors (DETFs) were acquired from the Cistrome database. Thereafter, a TFs-mediated IRGs network was constructed to identify the candidate mechanisms for those DEIRGs in LUSC at molecular level. Moreover, Gene Ontology (GO), together with Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, was conducted for exploring those functional enrichments for DEIRGs. Besides, univariate as well as multivariate Cox regression analysis was conducted for establishing a prediction model for DEIRGs biomarkers. In addition, the relationship between the prognostic model and immunocytes was further explored through immunocyte correlation analysis. In total, 3,599 DEGs, 223 DEIRGs, and 46 DETFs were obtained from LUSC tissues and adjacent non-carcinoma tissues. According to multivariate Cox regression analysis, 10 DEIRGs (including CALCB, GCGR, HTR3A, AMH, VGF, SEMA3B, NRTN, ENG, ACVRL1, and NR4A1) were retrieved to establish a prognostic model for LUSC. Immunocyte infiltration analysis showed that dendritic cells and neutrophils were positively correlated with IRGs, which possibly exerted an important part within the IME of LUSC. Our study identifies a prognostic model based on IRGs, which is then used to predict LUSC prognosis and analyze immunocyte infiltration. This may provide a novel insight for exploring the potential IRGs in the IME of LUSC.

Analysis of prognostic genes in the tumor microenvironment of lung adenocarcinoma

Background

Prognostic genes in the tumor microenvironment play an important role in immune biological processes and the response of cancer to immunotherapy. Thus, we aimed to assess new biomarkers that are associated with immune/stromal cells in lung adenocarcinomas (LUAD) using the ESTIMATE algorithm, which also significantly affects the prognosis of cancer.

Methods

The RNA sequencing (RNA-Seq) and clinical data of LUAD were downloaded from the the Cancer Genome Atlas (TCGA ). The immune and stromal scores were calculated for each sample using the ESTIMATE algorithm. The LUAD gene chip expression profile data and the clinical data (GSE37745, GSE11969, and GSE50081) were downloaded from the Gene Expression Omnibus (GEO) for subsequent validation analysis. Differentially expressed genes were calculated between high and low score groups. Univariate Cox regression analysis was performed on differentially expressed genes (DEGs) between the two groups to obtain initial prognosis genes. These were verified by three independent LUAD cohorts from the GEO database. Multivariate Cox regression was used to identify overall survival-related DEGs. UALCAN and the Human Protein Atlas were used to analyze the mRNA /protein expression levels of the target genes. Immune cell infiltration was evaluated using the Tumor Immune Estimation Resource (TIMER) and CIBERSORT methods, and stromal cell infiltration was assessed using xCell.

Results

In this study, immune scores and stromal scores are significantly associated with the clinical characteristics of LUAD, including T stage, M stage, pathological stage, and overall survival time. 530 DEGs (18 upregulated and 512 downregulated) were found to coexist in the difference analysis with the immune scores and stromal scores subgroup. Univariate Cox regression analysis showed that 286 of the 530 DEGs were survival-related genes (p < 0.05). Of the 286 genes initially identified, nine prognosis-related genes (CSF2RB, ITK, FLT3, CD79A, CCR4, CCR6, DOK2, AMPD1, and IGJ) were validated from three separate LUAD cohorts. In addition, functional analysis of DEGs also showed that various immunoregulatory molecular pathways, including regulation of immune response and the chemokine signaling pathways, were involved. Five genes (CCR6, ITK, CCR4, DOK2, and AMPD1) were identified as independent prognostic indicators of LUAD in specific data sets. The relationship between the expression levels of these genes and immune genes was assessed. We found that CCR6 mRNA and protein expression levels of LUAD were greater than in normal tissues. We evaluated the infiltration of immune cells and stromal cells in groups with high and low levels of expression of CCR6 in the TCGA LUAD cohort. In summary, we found a series of prognosis-related genes that were associated with the LUAD tumor microenvironment.

The premise of personalized immunotherapy for cancer dormancy

Progress in cancer therapies has resulted in improved survival of patients with early stage breast cancer. However, mortality remains high in patients with distant recurrence of the disease after initially successful treatment of early stage breast cancer. To this end, tumor recurrences have been attributed to the presence of dormant tumor cells in breast cancer patients and cancer survivors. Current clinical practice guidelines recommend a “wait and watch” approach for tumor recurrence. This is because of our limited understanding of tumor dormancy. Dormant tumor cells are quiescent, and thus, do not respond to chemotherapies or radiation therapies, and they are not operable. Therefore, immunotherapy is the only option for the treatment of tumor dormancy. However, gaps in our knowledge as to dormancy-specific antigens prevent a relapse preventing vaccine design. Here, we provide a critical review of cancer immunotherapy, and discuss empirical evidence related to naturally-occurring tumor dormancy and treatment-induced tumor dormancy at the site of primary tumor and in distant organs before and after cancer therapies. Finally, we suggest that personalized vaccines targeting dormancy-associated neoantigens, which can be given to patients with early stage disease after the completion of neoadjuvant therapies and tumor resection as well as to cancer survivors could eliminate relapse causing dormant cells and offer a cure for cancer.