T-cell death and cancer immune tolerance

ADGRE5-centered Tsurv model in T cells recognizes responders to neoadjuvant cancer immunotherapy

Background

Neoadjuvant immunotherapy with anti-programmed death-1 (neo-antiPD1) has revolutionized perioperative methods for improvement of overall survival (OS), while approaches for major pathologic response patients' (MPR) recognition along with methods for overcoming non-MPR resistance are still in urgent need.

Methods

We utilized and integrated publicly-available immune checkpoint inhibitors regimens (ICIs) single-cell (sc) data as the discovery datasets, and innovatively developed a cell-communication analysis pipeline, along with a VIPER-based-SCENIC process, to thoroughly dissect MPR-responding subsets. Besides, we further employed our own non-small cell lung cancer (NSCLC) ICIs cohort's sc data for validation in-silico. Afterward, we resorted to ICIs-resistant murine models developed by us with multimodal investigation, including bulk-RNA-sequencing, Chip-sequencing and high-dimensional cytometry by time of flight (CYTOF) to consolidate our findings in-vivo. To comprehensively explore mechanisms, we adopted 3D ex-vivo hydrogel models for analysis. Furthermore, we constructed an ADGRE5-centered Tsurv model from our discovery dataset by machine learning (ML) algorithms for a wide range of tumor types (NSCLC, melanoma, urothelial cancer, etc.) and verified it in peripheral blood mononuclear cells (PBMCs) sc datasets.

Results

Through a meta-analysis of multimodal sequential sc sequencing data from pre-ICIs and post-ICIs, we identified an MPR-expanding T cells meta-cluster (MPR-E) in the tumor microenvironment (TME), characterized by a stem-like CD8+ T cluster (survT) with STAT5-ADGRE5 axis enhancement compared to non-MPR or pre-ICIs TME. Through multi-omics analysis of murine TME, we further confirmed the existence of survT with silenced function and immune checkpoints (ICs) in MPR-E. After verification of the STAT5-ADGRE5 axis of survT in independent ICIs cohorts, an ADGRE5-centered Tsurv model was then developed through ML for identification of MPR patients pre-ICIs and post-ICIs, both in TME and PBMCs, which was further verified in pan-cancer immunotherapy cohorts. Mechanistically, we unveiled ICIs stimulated ADGRE5 upregulation in a STAT5-IL32 dependent manner in a 3D ex-vivo system (3D-HYGTIC) developed by us previously, which marked Tsurv with better survival flexibility, enhanced stemness and potential cytotoxicity within TME.

Conclusion

Our research provides insights into mechanisms underlying MPR in neo-antiPD1 and a well-performed model for the identification of non-MPR.

Advances in landscape and related therapeutic targets of the prostate tumor microenvironment

The distinct tumor microenvironment (TME) of prostate cancer (PCa), which promotes tumor proliferation and progression, consists of various stromal cells, immune cells, and a dense extracellular matrix (ECM). The understanding of the prostate TME extends to tertiary lymphoid structures (TLSs) and metastasis niches to provide a more concise comprehension of tumor metastasis. These constituents collectively structure the hallmarks of the pro-tumor TME, including immunosuppressive, acidic, and hypoxic niches, neuronal innervation, and metabolic rewiring. In combination with the knowledge of the tumor microenvironment and the advancement of emerging therapeutic technologies, several therapeutic strategies have been developed, and some of them have been tested in clinical trials. This review elaborates on PCa TME components, summarizes various TME-targeted therapies, and provides insights into PCa carcinogenesis, progression, and therapeutic strategies.

Engineering kinetics of TLR7/8 agonist release from bottlebrush prodrugs enables tumor-focused immune stimulation

Imidazoquinolines (IMDs), such as resiquimod (R848), are of great interest as potential cancer immunotherapies because of their ability to activate Toll-like receptor 7 (TLR7) and/or TLR8 on innate immune cells. Nevertheless, intravenous administration of IMDs causes severe immune-related toxicities, and attempts to improve their tissue-selective exposure while minimizing acute systemic inflammation have proven difficult. Here, using a library of R848 "bottlebrush prodrugs" (BPDs) that differ only by their R848 release kinetics, we explore how the timing of R848 exposure affects immune stimulation in vitro and in vivo. These studies led to the discovery of R848-BPDs that exhibit optimal activation kinetics to achieve potent stimulation of myeloid cells in tumors and substantial reductions in tumor growth following systemic administration in mouse syngeneic tumor models without any observable systemic toxicity. These results suggest that release kinetics can be tuned at the molecular level to provide safe yet effective systemically administered immunostimulant prodrugs for next-generation cancer immunotherapies.

Apoptosis: a Janus bifrons in T-cell immunotherapy

Immunotherapy has revolutionized the treatment of cancer. In particular, immune checkpoint blockade, bispecific antibodies, and adoptive T-cell transfer have yielded unprecedented clinical results in hematological malignancies and solid cancers. While T cell-based immunotherapies have multiple mechanisms of action, their ultimate goal is achieving apoptosis of cancer cells. Unsurprisingly, apoptosis evasion is a key feature of cancer biology. Therefore, enhancing cancer cells' sensitivity to apoptosis represents a key strategy to improve clinical outcomes in cancer immunotherapy. Indeed, cancer cells are characterized by several intrinsic mechanisms to resist apoptosis, in addition to features to promote apoptosis in T cells and evade therapy. However, apoptosis is double-faced: when it occurs in T cells, it represents a critical mechanism of failure for immunotherapies. This review will summarize the recent efforts to enhance T cell-based immunotherapies by increasing apoptosis susceptibility in cancer cells and discuss the role of apoptosis in modulating the survival of cytotoxic T lymphocytes in the tumor microenvironment and potential strategies to overcome this issue.

CD200+ cytotoxic T lymphocytes in the tumor microenvironment are crucial for efficacious anti-PD-1/PD-L1 therapy

Anti-PD-1/PD-L1 therapy, either by anti-PD-1 antibody or anti-PD-L1 antibody, has efficacy by reinvigorating tumor-infiltrating CD8⁺ T cells in a subset of patients with cancer, but it has unequal effects on heterogeneous CD8⁺ T cell populations. Hence, the subset crucial to efficacious PD-1 blockade therapy remains elusive. Here, we found an increase in tumor-infiltrating CD200⁺ cytotoxic T lymphocytes (CTLs) upon PD-1/PD-L1 blockade, with higher proportions of CD200⁺ T cells positively related to a favorable clinical outcome to anti-PD-1/PD-L1 therapy in three independent cohorts of patients with cancer. Using multiple mouse tumor models, we demonstrated that CD200⁺ CTLs are essential for efficacious anti-PD-L1 therapy. Mechanistically, we observed a unique chromatin landscape in CD200⁺ CTLs and found that these cells are enriched for tumor antigen-specific CTLs and have antitumor effector functions. Coinoculation of CD200⁺ CTLs with tumor cells led to robust tumor regression in two transplanted mouse models. Clinically, we found that infiltration of CD200⁺ CTLs into tumors could predict immunotherapy efficacy in six patient cohorts. Together, our findings reveal that CD200⁺ CTLs in the tumor microenvironment are crucial for efficacious anti-PD-1/PD-L1 therapy and could serve as a predictor of successful immunotherapy in the clinic.

Synergistic potential of immune checkpoint inhibitors and therapeutic cancer vaccines

Cancer vaccines and immune checkpoint inhibitors (ICIs) function at different stages of the cancer immune cycle due to their distinct mechanisms of action. Therapeutic cancer vaccines enhance the activation and infiltration of cytotoxic immune cells into the tumor microenvironment (TME), while ICIs, prevent and/or reverse the dysfunction of these immune cells. The efficacy of both classes of immunotherapy has been evaluated in monotherapy, but they have been met with several challenges. Although therapeutic cancer vaccines can activate anti-tumor immune responses, these responses are susceptible to attenuation by immunoregulatory molecules. Similarly, ICIs are ineffective in the absence of tumor-infiltrating lymphocytes (TILs). Further, ICIs are often associated with immune-related adverse effects that may limit quality of life and compliance. However, the combination of the improved immunogenicity afforded by cancer vaccines and restrained immunosuppression provided by immune checkpoint inhibitors may provide a suitable platform for therapeutic synergism. In this review, we revisit the history and various classifications of therapeutic cancer vaccines. We also provide a summary of the currently approved ICIs. Finally, we provide mechanistic insights into the synergism between ICIs and cancer vaccines.

Metabolic remodeling in tumor-associated macrophages contributing to antitumor activity of cryptotanshinone by regulating TRAF6-ASK1 axis

Dampening tumor growth by converting tumor-associated macrophages (TAMs) from M2/repair-types to M1/kill-types is of high interest. Here, we show that cryptotanshinone (CPT) can function as an antitumor immune modulator that switches TAMs from an M2 to an M1 phenotype, leading to tumor regression. An orthotopic triple-negative breast cancer (TNBC) implantation model was used to determine the role and mechanism of CPT in suppressing M1-to-M2 repolarization of TAMs. Co-culturing TNBC cells with CPT-treated macrophages reduced TNBC proliferation and motility, while in TNBC orthotopic mouse models, CPT treatment inhibited breast tumor formation.

Moreover, we identified that CPT inhibits mitochondrial oxidative phosphorylation and mitochondrial fusion via autophagy and transcriptional activation of the apoptosis signal-regulating kinase 1 (ASK1) pathway. Suppression of ASK1 downregulates autophagy and abolishes CPT-induced effects upon TAMs. In addition, CPT inhibits M2 macrophage differentiation and causes TRAF6 auto-ubiquitination-dependent activation of the ASK1, leading to M1 polarization. On the contrary, in M1 macrophage, CPT increases interaction of ASK1 and TRAF6 which induces ASK1 ubiquitination and degradation. Intriguingly, CPT plays opposite roles in the M1 and M2 phenotype. Our findings help to illuminate a previously unrecognized antitumor mechanism of CPT and suggest that this natural compound offers a macrophage-based approach for cancer immunotherapy.

Tobacco Use and Response to Immune Checkpoint Inhibitor Therapy in Non-Small Cell Lung Cancer

Tobacco is a known risk factor for lung cancer, and continued tobacco use is associated with poorer outcomes across multiple lung cancer treatment modalities including surgery, chemotherapy and radiation therapy. Less is known about the association of tobacco use and outcomes with immune checkpoint inhibitors (ICIs), which are becoming an important part of the treatment landscape in lung cancer, both in metastatic and curative settings. We reviewed the literature on the association of tobacco and tumor biology as it relates to immunotherapy. We also reviewed the association of tobacco use on outcomes among phase III randomized clinical trials involving ICIs in non-small cell lung cancer (NSCLC). We identified that patients with a smoking history may have a greater benefit with ICI treatment compared to never smokers in both treatment-naïve (HR 0.82, 95% CI 0.69–0.97, vs. HR 1.06, 95% CI 0.81–1.38) and pre-treated (HR 0.79, 95% CI 0.70–0.90 vs. 1.03, 95% CI 0.74–1.43) settings. In trials where smoking status was further defined, ex-smokers appear to demonstrate greater benefit with ICI therapy compared to current smokers (HR 0.78, 95% CI 0.59–1.01 vs. 0.91, 95% CI 0.72–1.14). We conclude by offering our perspective on future directions in this area of research, including implementation of standardized collection and analysis of tobacco use in clinical trials involving ICI therapy in lung cancer and other disease sites, and also evaluating how tobacco may affect toxicities related to ICI therapy. Based on our review, we believe that a patient’s history of tobacco smoking does have a role to play in guiding treatment decision making in patients with lung cancer.

The Inflammatory Status of Soluble Microenvironment Influences the Capacity of Melanoma Cells to Control T-Cell Responses

The development of immunotherapeutic approaches for the treatment of melanoma requires a better understanding of immunoescape mechanisms of tumor cells and how they interact with other tumor-resident cell types. Here, we evaluated how the conditioned media of resting (rCM) and immune-activated PBMCs (iCM) influence the ability of a metastatic melanoma cell line (MeWo) to control T-cells function. MeWo cells were expanded in RPMI, rCM, or iCM and the secretome generated after cell expansion was identified as MeSec (RPMI), niSec (non-inflammatory), or iSec (inflammatory secretome), respectively. Then, the immunomodulatory potential of such secretomes was tested in PHA-activated PBMCs. iCM induced higher levels of IFN-γ and IL-10 in treated melanoma cells compared to rCM, as well as higher IDO and PD-L1 expression. The iSec was able to inhibit T-cell activation and proliferation. Interestingly, PBMCs treated with iSec presented a reduced expression of the regulators of Th1 and Th2 responses T-BET and GATA-3, as well as low expression of IFN-γ, and co-stimulatory molecules TIM-3 and LAG-3. Importantly, our findings show that melanoma may benefit from an inflammatory microenvironment to enhance its ability to control the T-cell response. Interestingly, such an immunomodulatory effect involves the inhibition of the checkpoint molecules LAG-3 and TIM-3, which are currently investigated as important therapeutic targets for melanoma treatment. Further studies are needed to better understand how checkpoint molecules are modulated by paracrine and cell contact-dependent interaction between melanoma and immune cells. Such advances are fundamental for the development of new therapeutic approaches focused on melanoma immunotherapy.

m6A Regulator Expression Segregates Meningiomas Into Biologically Distinct Subtypes

BACKGROUND

Meningiomas are the most common primary intracranial tumors in adults. According to the 2021 World Health Organization (WHO) classification of central nervous system tumors, approximately 80% of meningiomas are WHO grade 1, that is, histopathologically benign, whereas about 20% are WHO grade 2 or grade 3, showing signs of atypia or malignancy. The dysregulation of N6-methylation (m⁶A) regulators is associated with disorders of diverse critical biological processes in human cancer. This study aimed to explore whether m⁶A regulator expression was associated with meningioma molecular subtypes and immune infiltration.

METHODS

We evaluated the m⁶A modification patterns of 160 meningioma samples based on 19 m⁶A regulators and correlated them with immune infiltration characteristics. Novel molecular subtypes were defined based on prognostic hub gene expression.

RESULTS

Two meningioma clusters were identified based on the expression of 19 m⁶A regulators. In cluster 1, 607 differentially expressed genes (DEGs) were upregulated and 519 were downregulated. A total of 1,126 DEGs comprised three gene expression modules characterized by turquoise, blue, and gray. Functional annotation suggested that the turquoise module was involved in Wnt-related and other important cancer-related pathways. We identified 32 hub genes in this module by constructing a protein-protein interaction network. The meningioma samples were divided into two molecular subtypes. EPN1, EXOSC4, H2AX, and MZT2B not only showed significant differences between meningioma molecular subtypes but also had the potential to be the marker genes of specific meningioma subtypes.

CONCLUSION

m⁶A regulator gene expression may be a novel prognostic marker in meningioma.

β3-Adrenoceptor, a novel player in the round-trip from neonatal diseases to cancer: Suggestive clues from embryo

The role of the β-adrenoceptors (β-ARs) in hypoxia-driven diseases has gained visibility after the demonstration that propranolol promotes the regression of infantile hemangiomas and ameliorates the signs of retinopathy of prematurity (ROP). Besides the role of β2-ARs, preclinical studies in ROP have also revealed that β3-ARs are upregulated by hypoxia and that they are possibly involved in retinal angiogenesis. In a sort of figurative round trip, peculiarities typical of ROP, where hypoxia drives retinal neovascularization, have been then translated to cancer, a disease equally characterized by hypoxia-driven angiogenesis. In this step, investigating the role of β3-ARs has taken advantage of the assumption that cancer growth uses a set of strategies in common with embryo development. The possibility that hypoxic induction of β3-ARs may represent one of the mechanisms through which primarily embryo (and then cancer, as an astute imitator) adapts to grow in an otherwise hostile environment, has grown evidence. In both cancer and embryo, β3-ARs exert similar functions by exploiting a metabolic shift known as the Warburg effect, by acquiring resistance against xenobiotics, and by inducing a local immune tolerance. An additional potential role of β3-AR as a marker of stemness has been suggested by the finding that its antagonism induces cancer cell differentiation evoking that β3-ARs may help cancer to grow in a nonhospital environment, a strategy also exploited by embryos. From cancer, the round trip goes back to neonatal diseases for which new possible interpretative keys and potential pharmacological perspectives have been suggested.

Immunotherapy for cancer treatment during pregnancy

Immunotherapy has greatly improved outcomes for subgroups of patients with cancer. As indications keep expanding, there is an unmet need to gain a better understanding of the effect of these therapies on pregnancy and fertility. During pregnancy, substantial adaptations occur in the maternal immune system to maintain protection against pathogens while avoiding detrimental reactions to the semi-allogeneic fetus. The pathways involved in the establishment of this fetomaternal tolerance can be hijacked by cancers. Immunotherapies that target these inhibitory pathways, or that directly interact with the regulatory immune cells involved in tolerance mechanisms, might therefore result in complications during pregnancy. Similarly, by activating the patient's immune system with immunotherapy, a broad range of immune-related adverse events can occur that could negatively affect the fetus or impede a future desired pregnancy. This Review summarises preclinical and clinical data related to the use of immunotherapy during pregnancy, including all approved immune checkpoint inhibitors, recombinant cytokines, cell therapies, vaccines, and immunomodulatory drugs.

Emerging role of tumor microenvironment derived exosomes in therapeutic resistance and metastasis through epithelial-to-mesenchymal transition

The tumor microenvironment (TME) constitutes multiple cell types including cancerous and non-cancerous cells. The intercellular communication between these cells through TME derived exosomes may either enhance or suppress the tumorigenic processes. The tumor-derived exosomes could convert an anti-tumor environment into a pro-tumor environment by inducing the differentiation of stromal cells into tumor-associated cells. The exosomes from tumor-associated stromal cells reciprocally trigger epithelial-to-mesenchymal transition (EMT) in tumor cells, which impose therapeutic resistance and metastasis. It is well known that these exosomes contain the signals of EMT, but how these signals execute chemoresistance and metastasis in tumors remains elusive. Understanding the significance and molecular signatures of exosomes transmitting EMT signals would aid in developing appropriate methods of inhibiting them. In this review, we focus on molecular signatures of exosomes that shuttle between cancer cells and their stromal populations in TME to explicate their impact on therapeutic resistance and metastasis through EMT. Especially Wnt signaling is found to be involved in multiple ways of exosomal transport and hence we decipher the biomolecules of Wnt signaling trafficked through exosomes and their potential in serving as therapeutic targets.

Identification of an apoptosis-related prognostic gene signature and molecular subtypes of clear cell renal cell carcinoma (ccRCC)

Previously studies have shown that apoptosis-related genes play an essential role in normal cell turnover, maintaining the immune system function, and inducing cell death. However, their prognostic roles in clear cell renal cell carcinoma (ccRCC) have not been thoroughly investigated. In the present study, apoptosis-related genes expression profiles from The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) database were used as training dataset and external validation dataset, respectively. According to the systematical analysis of the apoptosis-related gene expression profile, we constructed a gene signature to determine the role of apoptosis-related genes in the survival of ccRCC. We discovered that patients in the low-risk group have a better survival than high-risk group and the signature could serve as an independent prognostic factor. A nomogram, including a signature and clinical factors, were constructed to estimate the individual survival probability. The Gene set enrichment analysis (GSEA) identified some significant pathways which may contribute to understanding the underlying mechanism of ccRCC. In addition, the prognostic efficiency of the risk model was further validated in the disease free survival (DFS) and the ICGC dataset, respectively. We also identified three molecular subtypes (named C1, C2, and C3) based on apoptosis-related gene expression. We found that C1 was corresponding to a worse survival outcome and showed a high drug sensitivity of sorafenib and sunitinib. C2 and C3 were corresponding to a better survival outcome and presented a low drug sensitivity to sorafenib and sunitinib. Moreover, we found that C2 and C3 have more likelihood to be respond to immunotherapy. Together, the apoptosis-related gene signature and three molecular subtypes may promote the understanding of the underlying molecular mechanism of ccRCC, and provided reference for developing individualized treatment of the ccRCC patients.

Tumor-infiltrating CD8+ T cell antitumor efficacy and exhaustion: molecular insights

Host immunity has an essential role in the clinical management of cancers. Therefore, it is advantageous to choose therapies that can promote tumor cell death and concurrently boost host immunity. The dynamic tumor microenvironment (TME) determines whether an antineoplastic drug will elicit favorable or disparaging immune responses from tumor-infiltrating lymphocytes (TILs). CD8+ T cells are one of the primary tumor-infiltrating immune cells that deliver antitumor responses. Here, we review the influence of various factors in the TME on CD8+ T cell exhaustion and survival, and possible strategies for restoring CD8+ T cell effector function through immunotherapy.

COVID-19 and cancer: Sailing through the tides

The COVID-19 (coronavirus disease) pandemic caused by SARS-CoV-2 with its rapid expansion has led to extraordinary implications in our understanding of viral infections and their management globally. In this current scenario of unusual circumstances and public health emergency, the cancer care per se is facing unprecedented challenges. The peculiarity of the SARS-CoV-2 infections is still being uncovered as the pandemic spreads across the populations than showing signs of its curtailment. The review highlights the significance of idiosyncrasy of the SARS-Cov-2 infection especially putting forth the importance of immunosenescence, both in the COVID-19 specific immune response in the infected lungs of the elderly and in the cancer patients infected with SARS-CoV-2.The focus of the article is directed towards demystifying the unparalleled essence of a proprotein convertase, Furin in the biology of the SARS-Cov-2 infection and its role in facilitating viral transmission through expedited cellular entry into alveolar epithelial cells in COVID-19 infected cancer patients. The risk stratification of the cancer treatment and guidelines shaped up by national and international oncology societies in providing uncompromised patient care during the COVID-19 crisis have also been addressed. The global efforts towards vaccination in developing SARS CoV-2 immunity are also discussed in this article.

A Systematic Review of Blinatumomab in the Treatment of Acute Lymphoblastic Leukemia: Engaging an Old Problem With New Solutions

OBJECTIVE

To assess the current literature for blinatumomab in the treatment of adult and pediatric B-cell acute lymphoblastic leukemia (ALL).

DATA SOURCES

We conducted a PubMed (inception to December 11, 2020) and ClinicalTrials.gov systematic literature search using the following terms: blinatumomab, Blincyto, lymphoblastic leukemia, and bispecific T-cell engager.

STUDY SELECTION AND DATA EXTRACTION

All relevant published articles, package inserts, and meeting abstracts evaluating the use of blinatumomab in ALL were considered for inclusion.

DATA SYNTHESIS

Blinatumomab, a first-in-class bispecific T-cell engager monoclonal antibody, facilitates cytotoxic T-cell activation and subsequent eradication of CD19-positive B cells. The confirmatory phase III TOWER trial demonstrated superior overall survival (OS) with blinatumomab compared with standard chemotherapy (7.7 months vs 4.0 months) in relapsed and refractory (R/R) B-cell ALL. In the phase II BLAST trial, blinatumomab achieved a complete measurable residual disease (MRD) response in 78% of evaluable patients, with a median OS of 36.5 months. Potentially life-threatening cytokine release syndrome and neurotoxicity occurred in approximately 15% and 65% of patients, respectively.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Following initial Food and Drug Administration approval in 2014, blinatumomab gained expanded approval in pediatric patients and in Philadelphia chromosome-positive R/R ALL. In 2018, blinatumomab became the first and only drug approved for the treatment of persistent MRD in any hematologic malignancy. Emerging data demonstrate promising efficacy with blinatumomab in specific ALL settings, including frontline therapy, as a bridge to transplantation, and in "chemotherapy-free" combination regimens.

CONCLUSIONS

Blinatumomab provides a paradigm-shifting treatment option; however, many questions surrounding optimal patient selection, sequencing, and cost-effectiveness remain.

Tisagenlecleucel in Acute Lymphoblastic Leukemia: A Review of the Literature and Practical Considerations

OBJECTIVE

To evaluate the current literature for tisagenlecleucel in the treatment of relapsed/refractory (r/r) B-cell acute lymphoblastic leukemia (ALL).

DATA SOURCES

A literature search of PubMed (inception to June 18, 2020) and ClinicalTrials.gov was conducted using the following search terms: CTL019, chimeric antigen receptor, CAR-T, and tisagenlecleucel.

STUDY SELECTION AND DATA EXTRACTION

All trials evaluating the use of tisagenlecleucel in B-cell ALL were reviewed and considered for inclusion.

DATA SYNTHESIS

Tisagenlecleucel displayed overall remission rates ranging from 69% to 93% in patients who historically respond extremely poorly to salvage therapy. Remissions were durable, with 12-month relapse-free survival (RFS) rates of 55% to 59%. These promising results are tempered by the unique adverse effect profile of chimeric antigen receptor (CAR) T-cell therapy. Potentially life-threatening cytokine release syndrome (CRS) occurred in 77% to 100% of patients, and immune effector cell-associated neurotoxicity syndrome (ICANS) developed in 31% to 45% of patients receiving tisagenlecleucel.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

The successful utilization of tisagenlecleucel therapy requires meticulous planning, prudent patient selection, multidisciplinary collaboration, and expert training to ensure optimal patient care. The complex interplay of patient- and treatment-related factors creates problematic barriers that must be expertly navigated by the health care team and authorized treatment center.

CONCLUSIONS

As the first US Food and Drug Administration-approved gene therapy, tisagenlecleucel heralds an immunotherapeutic breakthrough for treating pediatric and young adult patients with r/r B-cell ALL. Many questions surrounding patient-specific gene and cellular therapies remain, but their transformative potential in cancer care remains promising.

Pilot study of combined aerobic and resistance exercise on fatigue for patients with head and neck cancer: Inflammatory and epigenetic changes

This pilot study examined whether a combined aerobic resistance exercise program reduced fatigue and the potential inflammatory and epigenetic mechanisms in patients with head and neck cancer (HNC) receiving intensity-modulated radiotherapy. The exercise group (N = 12) received a 3-month supervised aerobic resistance exercise intervention that was initiated before a 6-week radiotherapy regimen; the control group (N = 14) received standard care. Fatigue was measured using Multidimensional Fatigue Inventory-20; physical function measures included a 6-minute walk distance (6MWD), chair stands, bicep curls, and hand grip strength. Inflammatory markers and DNA methylation data were acquired using standardized protocol. Patients were mostly white (93%) and male (81%) with a mean age of 57 years. At the end of the intervention, the exercise group had a marginal decrease in fatigue compared with the control (-5.0 vs. 4.9; P = 0.10). The exercise group had a significantly greater improvement in 6MWD (29.8 vs. -55.5 m; P = 0.04), and a marginally smaller decline in hand grip (-0.3 vs. -5.8 lbs; P = 0.05) at the end of the intervention than the control. No significant difference in inflammatory markers was observed between groups. Lower plasma interleukin (IL) 6, IL1 receptor antagonist, tumor necrosis factor α (TNFα), soluble TNF receptor II and C-reactive protein were significantly associated with increased 6MWD, chair stand, and bicep curl at the end of the intervention (p < 0.05). Among the 1152 differentially methylated sites (DMS) after intervention (p < 0.001), 163 DMS were located in gene promoter regions. Enrichment analysis suggested that the top 10 upstream regulators were associated with tumor (HNF4A, RPP38, HOXA9, SAHM1, CDK7, NDN, RPS15) and inflammation (IRF7, CRKL, ONECUT1). The top 5 diseases or functions annotations of the 62 hypermethylated DMS indicated anti-tumor and anti-inflammatory effects that might be linked to exercise. These findings suggest that exercise may improve physical performance and reduce fatigue, which could be further linked to decreased inflammation, during active radiotherapy for HNC patients. Larger studies are warranted.

Cathelicidin-Related Antimicrobial Peptide Regulates CD73 Expression in Mouse Th17 Cells via p38

The effector function of tumor-infiltrated CD4⁺ T cells is readily suppressed by many types of immune regulators in the tumor microenvironment, which is one of the major mechanisms of immune tolerance against cancer. Cathelicidin-related antimicrobial peptide (CRAMP), the mouse analog of LL-37 peptide in humans, is a cationic antimicrobial peptide belonging to the cathelicidin family; however, its secretion by cancer cells and role in the tumor microenvironment (TME) remain unclear. In this study, we explored the possibility of an interaction between effector CD4⁺ T cells and CRAMP using in vitro-generated mouse Th17 cells. We found that CRAMP stimulates Th17 cells to express the ectonucleotidase CD73, while simultaneously inducing cell death. This finding suggested that CD73-expressing Th17 cells may function as immune suppressor cells instead of effector cells. In addition, treatment of pharmacological inhibitors of the transforming growth factor-beta (TGF-β) signaling pathway showed that induction of CD73 expression is mediated by the p38 signaling pathway. Overall, our findings suggest that tumor-derived LL-37 likely functions as an immune suppressor that induces immune tolerance against tumors through shaping effector Th17 cells into suppressor Th17 cells, suggesting a new intervention target to improve cancer immunotherapy.

Emerging role of PTEN loss in evasion of the immune response to tumours

Mutations in PTEN activate the phosphoinositide 3-kinase (PI3K) signalling network, leading to many of the characteristic phenotypic changes of cancer. However, the primary effects of this gene on oncogenesis through control of the PI3K-AKT-mammalian target of rapamycin (mTOR) pathway might not be the only avenue by which PTEN affects tumour progression. PTEN has been shown to regulate the antiviral interferon network and thus alter how cancer cells communicate with and are targeted by immune cells. An active, T cell-infiltrated microenvironment is critical for immunotherapy success, which is also influenced by mutations in DNA damage repair pathways and the overall mutational burden of the tumour. As PTEN has a role in the maintenance of genomic integrity, it is likely that a loss of PTEN affects the immune response at two different levels and might therefore be instrumental in mediating failed responses to immunotherapy. In this review, we summarise findings that demonstrate how the loss of PTEN function elicits specific changes in the immune response in several types of cancer. We also discuss ongoing clinical trials that illustrate the potential utility of PTEN as a predictive biomarker for immune checkpoint blockade therapies.

Long non-coding RNAs in immune regulation and their potential as therapeutic targets

Long non-coding RNAs (lncRNAs) are potent regulators of immune cell development and function. Their implication in multiple immune-mediated disorders highlights lncRNAs as exciting biomarkers and potential drug targets. Recent technological innovations in oligo-based therapeutics, development of RNA-targeting small molecules, and CRISPR-based approaches, position RNA as the next therapeutic frontier. Here, we review the latest advances made toward understanding the role of lncRNAs in human immunological disorders and further discuss RNA-targeting approaches that could be potentially exploited to manipulate lncRNA function as a clinical intervention.

Safety and efficacy of axicabtagene ciloleucel in refractory large B-cell lymphomas

Aggressive large B-cell lymphomas represent a diverse population of diseases that are typically treated with anti-CD20 based immunochemotherapy. While this treatment is effective for a large proportion of patients, those that become refractory to induction therapy or experience disease relapse suffer an inferior overall prognosis, and novel treatment options are needed. Adoptive T-cell immunotherapy in the form of chimeric antigen receptor (CAR) T-cell therapy is one of the most revolutionary breakthroughs in the past several decades for the treatment of relapsed/refractory aggressive large B-cell lymphomas. Based on data from the pivotal ZUMA-1 study, axicabtagene ciloleucel (axi-cel) became the first-in-class anti-CD19 directed CAR T-cell therapy approved for patients with diffuse large B-cell lymphoma and other aggressive B-cell lymphoma variants. In this review, we provide an overview of CAR T-cell therapy, including its biology, manufacturing, and treatment course. In addition, we highlight the available efficacy data, review pertinent safety concerns, including cytokine release syndrome and neurologic toxicity, as well as provide an overview of emerging therapeutic strategies in the cellular therapy arena.

Case report: pembrolizumab-induced Type 1 diabetes in a patient with metastatic cholangiocarcinoma

BACKGROUND

Immune checkpoint inhibitors are novel cancer therapies associated with numerous autoimmune toxicities, some of which are only now being appreciated.

CASE PRESENTATION

A 67-year old female with metastatic cholangiocarcinoma and no prior history of diabetes was treated with leucovorin, fluorouracil, oxaliplatin and pembrolizumab. After eight cycles, she developed new onset type 1 diabetes mellitus with positive glutamic acid decarboxylase antibody titers. Conclusions: To our knowledge, this is the first reported case of PD-1 inhibitor associated Type 1 diabetes mellitus in a patient with cholangiocarcinoma and supports others' experiences that PD-1 inhibition can cause a spectrum of autoimmune adverse events that require clinical monitoring and periodic screenings.

The distribution and function of human memory T cell subsets in lung cancer

The distribution and function of T lymphocytes in human lung cancer remain limited. In this study, we investigated the properties of human T cell subsets in the blood of non-small cell lung cancer (NSCLC) patients. We found a relatively normal level of CD4+ subsets in the blood of NSCLC patients, but CD8+ effector T cells increased and CD8+ effector memory cells declined compared to the healthy donors. To further analyze their properties, we stimulated the peripheral blood mononuclear cells (PBMCs) of NSCLC patients by mitogens to examine cytokine production. Our data suggest that both CD4+ and CD8+ naïve cells in NSCLC patients significantly reduced IFN-γ and TNF-α production. Additionally, fewer CD8+ effector cells produced IFN-γ and TNF-α in NSCLC patients than in healthy subjects. Moreover, similar results were observed for CD4+ or CD8+ memory cells in NSCLC patients for the production of IFN-γ, TNF-α, and IL-17. Therefore, our results strongly suggest that the function of CD4+ and CD8+ T lymphocytes in NSCLC patients is compromised or dysregulated. The development of vaccines and antitumor immunotherapy may be essential for the treatment of lung cancer patients.

Targeted drug delivery to melanoma

Melanoma derived from melanocytes is the most aggressive genre of skin cancer. Although the considerable advancement in the study of human cancer biology and drug discovery, most advanced melanoma patients are inevitably unable to be cured. With the emergence of nanotechnology, the use of nano-carriers is widely expected to alter the landscape of melanoma treatment. In this review, we will discuss melanoma biology, current treatment options, mechanisms behind drug resistance, and nano-based solutions for effective anti-cancer therapy, followed by challenges and perspectives in both pre-clinical and clinical settings.

[The biological rationale for immunotherapy in cancer]

INTRODUCTION

Immunotherapy aims to promote the immune system's activity against malignant cells by stimulating the response to several tumor antigens.

STATE OF THE ART

Immunosurveillance may adjust the immunogenicity of tumors. To be effective, immunity must induce the specific activation of CD4+ and CD8+ T lymphocytes, as well as activation of innate immunity. Activator and inhibitory costimulatory molecules regulate T lymphocyte activation at immunity checkpoints such as PD-1/PD-L1 and CTLA-4. Adaptive immune resistance confers tumour resistance to immunosurveillance through these immune checkpoints.

PERSPECTIVES

Approaches involving the combination of several immunotherapies with each other or with chemotherapy and radiotherapy and antibodies against other molecules of costimulation are under development. The development of biomarkers, which can select a targeted population and predict therapeutic response, represents a major challenge. Tumour high-throughput sequencing could refine "immunoscore". Intratumoral T cell receptor seems to represent a promising biomarker.

CONCLUSIONS

Numerous challenges still remain in developing research approaches for the development of immunotherapies.

N-acetyl cysteine protects anti-melanoma cytotoxic T cells from exhaustion induced by rapid expansion via the downmodulation of Foxo1 in an Akt-dependent manner

Therapeutic outcomes for adoptive cell transfer (ACT) therapy are constrained by the quality of the infused T cells. The rapid expansion necessary to obtain large numbers of cells results in a more terminally differentiated phenotype with decreased durability and functionality. N-acetyl cysteine (NAC) protects against activation-induced cell death (AICD) and improves anti-tumor efficacy of Pmel-1 T cells in vivo. Here, we show that these benefits of NAC can be extended to engineered T cells and significantly increases T-cell survival within the tumor microenvironment. The addition of NAC to the expansion protocol of human TIL13838I TCR-transduced T cells that are under evaluation in a Phase I clinical trial, demonstrated that findings in murine cells extend to human cells. Expansion of TIL13838I TCR-transduced T cells in NAC also increased their ability to kill target cells in vitro. Interestingly, NAC did not affect memory subsets, but diminished up-regulation of senescence (CD57) and exhaustion (PD-1) markers and significantly decreased expression of the transcription factors EOMES and Foxo1. Pharmacological inhibition of the PI3K/Akt pathway ablates the decrease in Foxo1 induced by NAC treatment of activated T cells. This suggests a model in which NAC through PI3K/Akt activation suppresses Foxo1 expression, thereby impacting its transcriptional targets EOMES, PD-1, and granzyme B. Taken together, our results indicate that NAC exerts pleiotropic effects that impact the quality of TCR-transduced T cells and suggest that the addition of NAC to current clinical protocols should be considered.

Exhaustion of T lymphocytes in the tumor microenvironment: Significance and effective mechanisms

T lymphocytes play crucial roles in adaptive immune responses to tumors. However, due to different tolerance mechanisms and inhibitory effects of the tumor microenvironment (TME) on T cells, responses to tumors are insufficient. In fact, cellular and molecular suppressive mechanisms repress T cell responses in the TME, resulting in senescent, anergic and exhausted lymphocytes. Exhaustion is a poor responsive status of T cells, with up-regulated expression of inhibitory receptors, decreased production of effective cytokines, and reduced cytotoxic activity. Low immunogenicity of tumor antigens and inadequate presentation of tumor-specific antigens results in inappropriate activation of naive T lymphocytes against tumor antigens. Moreover, when effector cytotoxic T cells enter TME, they encounter a complicated network of cells and cytokines that suppress their effectiveness and turn them into exhausted T cells. Thus, the mechanism of T cell exhaustion in cancer is different from that in chronic infections. In this review we will discuss the main components such as inhibitory receptors, inflammatory cells, stromal cells, cytokine milieu as well as environmental and metabolic conditions in TME which play role in development of exhaustion. Furthermore, recent therapeutic methods available to overcome exhaustion will be discussed.

Metabolic reprogramming and apoptosis sensitivity: Defining the contours of a T cell response

An effective adaptive immune response hinges on the rapid clonal expansion of T cells in response to antigen. The sensitivity of these T cells to programmed cell death (i.e. apoptosis) is carefully calibrated at various stages to ensure a robust yet measured reaction that resolves without inflicting unintended damage to host tissues. To meet bioenergetic demands associated with vigorous proliferation, acquisition of effector functions, and memory formation, T cells also undergo dynamic changes in their metabolism at every stage of this response. In this review, we focus on relatively recent studies that illuminate intimate links between metabolic programs and apoptosis sensitivity in T cells. We then examine how these connections ultimately influence T cell survival and function within the metabolically taxing environs of the tumor microenvironment.

Tumor immunotherapy: drug-induced neoantigens (xenogenization) and immune checkpoint inhibitors

More than 40 years ago, we discovered that novel transplantation antigens can be induced in vivo or in vitro by treating murine leukemia with dacarbazine. Years later, this phenomenon that we called "Chemical Xenogenization" (CX) and more recently, "Drug-Induced Xenogenization" (DIX), was reproduced by Thierry Boon with a mutagenic/carcinogenic compound (i.e. N-methyl-N'-nitro-N-nitrosoguanidine). In both cases, the molecular bases of DIX rely on mutagenesis induced by methyl adducts to oxygen-6 of DNA guanine. In the present review we illustrate the main DIX-related immune-pharmacodynamic properties of triazene compounds of clinical use (i.e. dacarbazine and temozolomide).In recent years, tumor immunotherapy has come back to the stage with the discovery of immune checkpoint inhibitors (ICpI) that show an extraordinary immune-enhancing activity. Here we illustrate the salient biochemical features of some of the most interesting ICpI and the up-to-day status of their clinical use. Moreover, we illustrate the literature showing the direct relationship between somatic mutation burden and susceptibility of cancer cells to host's immune responses.When DIX was discovered, we were not able to satisfactorily exploit the possible presence of triazene-induced neoantigens in malignant cells since no device was available to adequately enhance host's immune responses in clinical settings. Today, ICpI show unprecedented efficacy in terms of survival times, especially when elevated mutation load is associated with cancer cells. Therefore, in the future, mutation-dependent neoantigens obtained by appropriate pharmacological intervention appear to disclose a novel approach for enhancing the therapeutic efficacy of ICpI in cancer patients.

Understanding the role of PD-L1/PD1 pathway blockade and autophagy in cancer therapy

Autophagy is a vital, physiological catabolic process for cell survival by which cells clear damaged organelles and recycle nutrients when homeostasis is maintained. Cancer is a complex disease with uncontrolled growth of cancer cells. Recent studies have suggested the role of autophagy in cancer. A complex relationship exists between autophagy and cancer, since autophagy can contribute to the survival or the destruction of malignant cells depending on the stage of tumor development. In this review, we describe in detail the mechanism underlying autophagy in cancer cells and the intricate involvement of the programmed cell death-1 (PD1) receptor with its ligand (PD-L1). The overexpression of PD-L1 receptors on cancer cell membranes has been observed in several types of cancers. The interaction of PD-L1 on cancer cells with PD1 on the surface of T-cells causes cancer cells to escape from the immune system by preventing the activation of new cytotoxic T-cells in the lymph nodes and subsequent recruitment to the tumor. In addition to its immunopathogenicity, PD1 has been related to autophagy. Reduction of this receptor due to treatment increases autophagy, therefore promoting the recycling of nutrients and clearance of toxic species, consequently promoting cell survival. In addition, PD-L1/PD1 engagement can induce autophagy in nearby T-cells due to a decrease in the amino acids tryptophan and arginine and due to the deprivation of nutrients such as glucose followed by a reduction in glucose metabolism. Resistance to cancer therapies is attributed to various pathways in oncogenesis including, inhibition of tumor suppressors, alteration of the tumor metabolic environment, and upregulation of autophagy. Here we explore the interaction between the immunosuppressive PD-L1/PD1 engagement and autophagy mechanisms, and evaluate the impact of inhibition of these pathways in augmenting antitumor efficacy.

Downregulation of L-arginine metabolism in dendritic cells induces tolerance to exogenous antigen

Dendritic cells (DC) are potential tools for therapeutic applications and several strategies to generate tolerogenic DCs are under investigation. When activated by cytokines and microbial products, DCs express mediators that modulate immune responses. In this regard, the metabolites generated by the activities of inducible nitric oxide synthase (iNOS) and arginase in DCs seem to play important roles. Here, we evaluated the effects of adoptive transfer of DCs generated in vitro from bone marrow precursors (BMDC) modulated with L-NAME (Nω-nitro-L-arginine methyl ester) and NOHA (NG-Hydroxy-L-arginine), inhibitors of iNOS and arginase, respectively, upon the immune response of the wild type (BALB/c) and OVA-TCR transgenic (DO11.10) mice. The modulation with L-NAME increased CD86 expression in BMDC, whereas treatment with NOHA increased both CD80 and CD86 expression. Adoptive transfer of either L-NAME- or NOHA-modulated BMDCs to BALB/c mice reduced the plasma levels of ovalbumin-specific antibody as well as proliferation and cytokine secretion in cultures of spleen cells in comparison adoptive transfer of non-modulated DCs. Conversely, transfer of both modulated and non-modulated BMDCs had no effect on immune response of DO11.10 mice. Together, these results show that the treatment with iNOS and Arg inhibitors leads to increased expression of co-stimulatory molecules in DCs, and provides evidences that L-arginine metabolism may be an important therapeutic target for modulating immune responses in inflammatory disorders.

Salmonella overcomes tumor immune tolerance by inhibition of tumor indoleamine 2, 3-dioxygenase 1 expression

Over the past decades, Salmonella has been proven capable of inhibiting tumor growth. It can specifically target tumors and due to its facultative anaerobic property, can be more penetrative than other drug therapies. However, the molecular mechanism by which Salmonella inhibits tumor growth is still incompletely known. The antitumor therapeutic effect mediated by Salmonella is associated with an inflammatory immune response at the tumor site and a T cell-dependent immune response. Many tumors have been proven to have a high expression of indoleamine 2, 3-dioxygenase 1 (IDO), which is a rate-limiting enzyme that catalyzes tryptophan to kynurenine, thus causing immune tolerance within the tumor microenvironment. With decreased expression of IDO, increased immune response can be observed, which might be helpful when developing cancer immunotherapy. The expression of IDO was decreased after tumor cells were infected with Salmonella. In addition, Western blot analysis showed that the expression levels of phospho-protein kinase B (P-AKT), phospho-mammalian targets of rapamycin (P-mTOR), and phospho-p70 ribosomal s6 kinase (P-p70s6K) in tumor cells were decreased after Salmonella infection. In conclusion, our results indicate that Salmonella inhibits IDO expression and plays a crucial role in anti-tumor therapy, which might be a promising strategy combined with other cancer treatments.

Chimeric Antigen Receptor T-Cell Therapy for the Community Oncologist

: The field of cancer immunotherapy has rapidly progressed in the past decade as several therapeutic modalities have entered into the clinic. One such immunotherapy that has shown promise in the treatment of cancer is the use of chimeric antigen receptor (CAR)-modified T lymphocytes. CARs are engineered receptors constructed from antigen recognition regions of antibodies fused to T-cell signaling and costimulatory domains that can be used to reprogram a patient's T cells to specifically target tumor cells. CAR T-cell therapy has demonstrated sustained complete responses for some patients with advanced leukemia, and a number of CAR therapies are being evaluated in clinical studies. CAR T-cell therapy-associated toxicities, including cytokine release syndrome, macrophage activation syndrome, and tumor lysis syndrome, have been observed and effectively managed in the clinic. In patients with significant clinical responses, sustained B-cell aplasia has also been observed and is a marker of CAR T-cell persistence that might provide long-term disease control. Education on CAR T-cell therapy efficacy and safety management is critical for clinicians and patients who are considering this novel type of treatment. In the present report, the current landscape of CAR T-cell therapy, the effective management of patients undergoing treatment, and which patients are the most suitable candidates for current trials are discussed.

IMPLICATIONS FOR PRACTICE

The present report describes the current status of chimeric antigen receptor (CAR) T lymphocytes as an immunotherapy for patients with relapsed or refractory B-cell malignancies. CAR T cells targeting CD19, a protein expressed on many B-cell malignancies, typically induce high complete response rates in patients with B-cell leukemia or lymphoma who have very limited therapeutic options. Recent clinical trial results of CD19 CAR T-cell therapies and the management of CAR T-cell-associated adverse events are discussed. The present report will therefore inform physicians regarding the efficacy and safety of CAR T cells as a therapy for B-cell malignancies.

Current therapeutic vaccination and immunotherapy strategies for HPV-related diseases

Carcinomas of the anogenital tract, in particular cervical cancer, remains one of the most common cancers in women, and represent the most frequent gynecological malignancies and the fourth leading cause of cancer death in women worldwide. Human papillomavirus (HPV)-induced lesions are immunologically distinct in that they express viral antigens, which are necessary to maintain the cancerous phenotype. The causal relationship between HPV infection and anogenital cancer has prompted substantial interest in the development of therapeutic vaccines against high-risk HPV types targeting the viral oncoproteins E6 and E7. This review will focus on the most recent clinical trials for immunotherapies for mucosal HPV-induced lesions as well as emerging therapeutic strategies that have been tested in pre-clinical models for HPV-induced diseases. Progress in peptide- and protein-based vaccines, DNA-based vaccines, viral/bacterial vector-based vaccines, immune checkpoint inhibition, immune response modifiers, and adoptive cell therapy for HPV will be discussed.

Live-Attenuated Bacterial Vectors: Tools for Vaccine and Therapeutic Agent Delivery

Genetically attenuated microorganisms, including pathogenic and commensal bacteria, can be engineered to carry and deliver heterologous antigens to elicit host immunity against both the vector as well as the pathogen from which the donor gene is derived. These live attenuated bacterial vectors have been given much attention due to their capacity to induce a broad range of immune responses including localized mucosal, as well as systemic humoral and/or cell-mediated immunity. In addition, the unique tumor-homing characteristics of these bacterial vectors has also been exploited for alternative anti-tumor vaccines and therapies. In such approach, tumor-associated antigen, immunostimulatory molecules, anti-tumor drugs, or nucleotides (DNA or RNA) are delivered. Different potential vectors are appropriate for specific applications, depending on their pathogenic routes. In this review, we survey and summarize the main features of the different types of live bacterial vectors and discussed the clinical applications in the field of vaccinology. In addition, different approaches for using live attenuated bacterial vectors for anti-cancer therapy is discussed, and some promising pre-clinical and clinical studies in this field are outlined.

T-cell exhaustion in the tumor microenvironment

T-cell exhaustion was originally identified during chronic infection in mice, and was subsequently observed in humans with cancer. The exhausted T cells in the tumor microenvironment show overexpressed inhibitory receptors, decreased effector cytokine production and cytolytic activity, leading to the failure of cancer elimination. Restoring exhausted T cells represents an inspiring strategy for cancer treatment, which has yielded promising results and become a significant breakthrough in the cancer immunotherapy. In this review, we overview the updated understanding on the exhausted T cells in cancer and their potential regulatory mechanisms and discuss current therapeutic interventions targeting exhausted T cells in clinical trials.

An Autocrine Cytokine/JAK/STAT-Signaling Induces Kynurenine Synthesis in Multidrug Resistant Human Cancer Cells

Background

Multidrug resistant cancer cells are hard to eradicate for the inefficacy of conventional anticancer drugs. Besides escaping the cytotoxic effects of chemotherapy, they also bypass the pro-immunogenic effects induced by anticancer drugs: indeed they are not well recognized by host dendritic cells and do not elicit a durable anti-tumor immunity. It has not yet been investigated whether multidrug resistant cells have a different ability to induce immunosuppression than chemosensitive ones. We addressed this issue in human and murine chemosensitive and multidrug resistant cancer cells.

Results

We found that the activity and expression of indoleamine 2,3-dioxygenase 1 (IDO1), which catalyzes the conversion of tryptophan into the immunosuppressive metabolite kynurenine, was higher in all the multidrug resistant cells analyzed and that IDO1 inhibition reduced the growth of drug-resistant tumors in immunocompetent animals. In chemoresistant cells the basal activity of JAK1/STAT1 and JAK1/STAT3 signaling was higher, the STAT3 inhibitor PIAS3 was down-regulated, and the autocrine production of STAT3-target and IDO1-inducers cytokines IL-6, IL-4, IL-1β, IL-13, TNF-α and CD40L, was increased. The disruption of the JAK/STAT signaling lowered the IDO1 activity and reversed the kynurenine-induced pro-immunosuppressive effects, as revealed by the restored proliferation of T-lymphocytes in STAT-silenced chemoresistant cells.

Conclusions

Our work shows that multidrug resistant cells have a stronger immunosuppressive attitude than chemosensitive cells, due to the constitutive activation of the JAK/STAT/IDO1 axis, thus resulting chemo- and immune-evasive. Disrupting this axis may significantly improve the efficacy of chemo-immunotherapy protocols against resistant tumors.

Activation-induced and damage-induced cell death in aging human T cells

In multicellular organisms the proper system functionality is ensured by the balance between cell division, differentiation, senescence and death. This balance is changed during aging. Immunosenescence plays a crucial role in aging and leads to the shrinkage of T cell repertoire and the propensity to apoptosis. The elimination of expanded T cells at the end of immune response is crucial to maintain homeostasis and avoid any uncontrolled inflammation. Resting mature T lymphocytes, when activated via their antigen-specific receptor (TCR) and CD28 co-receptor, start to proliferate and then undergo the so called activation induced cell death (AICD), which mechanistically is triggered by the death receptor and leads to apoptosis. T lymphocytes, like other cells, are also exposed to damage, which can trigger the so called damage-induced cell death (DICD). It was hypothesized that oxidative stress and chronic antigenic load increasing with age reduced lymphocyte susceptibility to DICD and enhanced a proinflamatory status leading to increased AICD. However, data collected so far are inconsistent and does not support this assumption. Systematic and comprehensive studies are still needed for conclusive elucidation of the role of AICD and DICD in human immunosenescence, including the role of autophagy and necroptosis in the processes.

The deaths of a cell: how language and metaphor influence the science of cell death

Multicellular development and tissue maintenance involve the regular elimination of damaged and healthy cells. The science of this genetically regulated cell death is particularly rich in metaphors: 'programmed cell death' or 'cell suicide' is considered an 'altruistic' act on the part of a cell for the benefit of the organism as a whole. It is also considered a form of 'social control' exerted by the body/organism over its component cells. This paper analyzes the various functions of these metaphors and critical discussion about them within the scientific community. Bodies such as the Nomenclature Committee on Cell Death (NCCD) have been charged with bringing order to the language of cell death to facilitate scientific progress. While the NCCD recommends adopting more objective biochemical terminology to describe the mechanisms of cell death, the metaphors in question retain an important function by highlighting the broader context within which cell death occurs. Scientific metaphors act as conceptual 'tools' which fulfill various roles, from highlighting a phenomenon as of particular interest, situating it in a particular context, or suggesting explanatory causal mechanisms.

Natural history of hepatic metastases from colorectal cancer - pathobiological pathways with clinical significance

Colorectal cancer hepatic metastases represent the final stage of a multi-step biological process. This process starts with a series of mutations in colonic epithelial cells, continues with their detachment from the large intestine, dissemination through the blood and/or lymphatic circulation, attachment to the hepatic sinusoids and interactions with the sinusoidal cells, such as sinusoidal endothelial cells, Kupffer cells, stellate cells and pit cells. The metastatic sequence terminates with colorectal cancer cell invasion, adaptation and colonisation of the hepatic parenchyma. All these events, termed the colorectal cancer invasion-metastasis cascade, include multiple molecular pathways, intercellular interactions and expression of a plethora of chemokines and growth factors, and adhesion molecules, such as the selectins, the integrins or the cadherins, as well as enzymes including matrix metalloproteinases. This review aims to present recent advances that provide insights into these cell-biological events and emphasizes those that may be amenable to therapeutic targeting.

Indoleamine-2,3-dioxygenase elevated in tumor-initiating cells is suppressed by mitocans

Tumor-initiating cells (TICs) often survive therapy and give rise to second-line tumors. We tested the plausibility of sphere cultures as models of TICs. Microarray data and microRNA data analysis confirmed the validity of spheres as models of TICs for breast and prostate cancer as well as mesothelioma cell lines. Microarray data analysis revealed the Trp pathway as the only pathway upregulated significantly in all types of studied TICs, with increased levels of indoleamine-2,3-dioxygenase-1 (IDO1), the rate-limiting enzyme of Trp metabolism along the kynurenine pathway. All types of TICs also expressed higher levels of the Trp uptake system consisting of CD98 and LAT1 with functional consequences. IDO1 expression was regulated via both transcriptional and posttranscriptional mechanisms, depending on the cancer type. Serial transplantation of TICs in mice resulted in gradually increased IDO1. Mitocans, represented by α-tocopheryl succinate and mitochondrially targeted vitamin E succinate (MitoVES), suppressed IDO1 in TICs. MitoVES suppressed IDO1 in TICs with functional mitochondrial complex II, involving transcriptional and posttranscriptional mechanisms. IDO1 increase and its suppression by VE analogues were replicated in TICs from primary human glioblastomas. Our work indicates that IDO1 is increased in TICs and that mitocans suppress the protein.

A multiantigen vaccine targeting neu, IGFBP-2, and IGF-IR prevents tumor progression in mice with preinvasive breast disease

A multiantigen multipeptide vaccine, targeting proteins expressed in preinvasive breast lesions, can stimulate type I CD4(+) T cells which have been shown to be deficient in both patients with breast cancer and mice that develop mammary tumors. Transgenic mice (TgMMTV-neu) were immunized with a multiantigen peptide vaccine specific for neu, insulin-like growth factor-binding protein 2 and insulin-like growth factor receptor-I at a time when some of the animals already had preinvasive lesions (18 weeks of age). Although immunization with each individual antigen was partially effective in inhibiting tumor growth, immunization with the multiantigen vaccine was highly effective, blocking development of palpable lesions in 65% of mice and slowing tumor growth in the infrequent palpable tumors, which did arise. Protection was mediated by CD4(+) T cells, and the few slow-growing tumors that did develop demonstrated a significant increase in intratumoral CD8(+) T cells as compared with controls (P = 0.0007). We also combined the vaccine with agents that were, by themselves, partially effective inhibitors of tumor progression in this model; lapatinib and the RXR agonist bexarotene. Although the combination of lapatinib and vaccination performed similarly to vaccination alone (P = 0.735), bexarotene and vaccination significantly enhanced disease-free survival (P < 0.0001), and approximately 90% of the mice showed no pathologic evidence of carcinomas at one year. The vaccine also demonstrated significant clinical efficacy in an additional transgenic model of breast cancer (TgC3(I)-Tag). Chemoimmunoprevention combinations may be an effective approach to breast cancer prevention even when the vaccine is administered in the presence of subclinical disease.