Innate Tumor Immune Surveillance

Screening of prognosis-related Immune cells and prognostic predictors in Colorectal Cancer Patients

OBJECTIVE

To accurately screen potential immune cells that can predict the survival of colorectal cancer (CRC) patients and identify related prognostic predictors.

METHODS

The sample data of CRC patients were downloaded from the GEO database as a training set to establish a prognosis-scoring model and screen prognosis-related immune cells. The sample data of CRC patients from the TCGA database were used as the validation set. Simultaneously, cancer tissue samples from 116 patients with CRC diagnosed pathologically in Shanghai Dongfang Hospital were collected to analyze the relationship of prognosis-related immune cells with patients' survival, and clinical and pathological parameters, and to screen prognostic predictors.

RESULTS

Prognosis-related immune cells screened from GEO and TCGA databases mainly included Follicular Helper T cells (Tfh), Monocytes and M2 Macrophages. In the training set, the 2,000- and 4,000-day survival rates were 48.3% and 10.7% in the low-risk group (N = 234), and 42.1% and 7.5% in the high-risk group (N = 214), respectively. In the validation set, the 2,000- and 4,000-day survival rates were 34.8% and 8.6% in the low-risk group (N = 187), and 28.9% and 6.1% in the high-risk group (N = 246), respectively. The prognosis of patients in the high-risk group was worse than that in the low-risk group (P < 0.05). Furthermore, the screened primary prognostic predictors were CD163 and CD4 + CXCR5. CD163 protein expression was distributed in Monocytes and M2 Macrophages. The 1,000- and 2,000-day survival rates were 56.1% and 7.0% in the CD163 low-expression group, and 40.7% and 1.7% in the high-expression group (N = 214), respectively, showing a worse prognosis in the high-expression group than that in the low-expression group. Meanwhile, the immune marker CD4 + CXCR5 could identify Tfh. The 1,000- and 2,000-day survival rates were 63.9% and 5.6% in the CD4 + CXCR5 high-expression group, and 33.3% and 2.8% in the low-expression group (N = 214), respectively, with a better prognosis in the high-expression group than that in the low-expression group.

CONCLUSION

Prognostic-related immune cells of CRC mainly include Tfh cells, Monocytes and M2 Macrophages. Monocytes and M2 Macrophages correlate negatively, while Tfh cells correlate positively with the prognosis of CRC patients. Immune markers CD163 and CD4 + CXCR5 can be considered as the prognostic predictors of CRC with clinical value of the application.

Exploration of the Tumor Mutational Burden as a Prognostic Biomarker and Related Hub Gene Identification in Prostate Cancer

To explore the signature function of the tumor mutational burden (TMB) and potential biomarkers in prostate cancer (PCa), transcriptome profiles, somatic mutation data, and clinicopathologic feature information were downloaded from The Cancer Genome Atlas (TCGA) database. R software package was used to generate a waterfall plot to summarize the specific mutation information and calculate the TMB value of PCa. Least absolute shrinkage and selection operator (LASSO) Cox regression analysis was used to select the hub genes related to the TMB from the ImmPort network to build a risk score (RS) model to evaluate prognostic values and plot Kaplan–Meier (K-M) curves to predict PCa patients survival. The results showed that PCa patients with a high TMB exhibited higher infiltration of CD8+ T cells and CD4+ T cells and better overall survival (OS) than those with a low TMB. The anti-Mullerian hormone (AMH), baculoviral IAP repeat-containing 5 (BIRC5), and opoid receptor kappa 1 (OPRK1) genes were three hub genes and their copy number variation (CNV) was relatively likely to affect the infiltration of immune cells. Moreover, PCa patients with low AMH or BIRC5 expression had a longer survival time and lower cancer recurrence, while elevated AMH or BIRC5 expression favored PCa progression. In contrast, PCa patients with low OPRK1 expression had poorer OS in the early stage of PCa and a higher recurrent rate than those with high expression. Taken together, these results suggest that the TMB may be a promising prognostic biomarker for PCa and that AMH, OPRK1, and BIRC5 are hub genes affecting the TMB; AMH, OPRK1, and BIRC5 could serve as potential immunotherapeutic targets for PCa treatment.

Lung-resident natural killer cells control pulmonary tumor growth in mice

Accumulating evidence indicates the importance of natural killer (NK) cells in controlling tumor growth and metastasis. NK cell subsets display diversities in their function and tissue distribution and Mac-1hi CD27lo NK cells are the predominant population of lung-resident NK cells. Although the lung is a major organ where primary tumor develops and cancer cells metastasize, there is no clear evidence whether circulating NK cells and/or tissue-resident NK cells control tumor growth in the lung. In the present study, we examined an antitumor function of lung-resident NK cells to control pulmonary tumor growth. In an orthotopic lung tumor model, NK cells controlled pulmonary tumor growth, and mature circulating NK cell subsets were increased in tumor-bearing lungs through a C-X-C motif chemokine receptor 3 (CXCR3)-dependent mechanism. Although such increase in migratory NK cell subsets can be blocked by anti-CXCR3 treatment, there was no difference in pulmonary tumor growth in anti-CXCR3-treated mice compared with control mice. In addition to pulmonary tumor growth, lung-resident NK cells, but not migratory NK cells, play a dominant role in controlling metastatic growth of cancer cells in lung. These results strongly indicate an importance of lung-resident NK cells for controlling pulmonary tumor growth.

Thinking Cancer

Evolutionary theories are necessarily invoked for understanding cancer development at the level of species, at the level of cells and tissues, and for developing effective therapies. It is crucial to view cancer in a Darwinian light, where the differential survival of individual cells is based on heritable variations. In the process of this somatic evolution, multicellularity controls are overridden by cancer cells, which become increasingly autonomous. Ecological epigenetics also helps understand how rogue cells that have basically the same DNA as their normal cell counterpart overcome the tissue homeostasis. As we struggle to wrap our minds around the complexity of these phenomena, we apply often times anthropomorphic terms, such as subversion, hijacking, or hacking, to describe especially the most complex among them-the interaction of tumors with the immune system. In this commentary we highlight examples of the anthropomorphic thinking of cancer and try to put into context the relative meaning of terms and the mechanisms that are oftentimes invoked to justify those terms.

Harnessing the effect of adoptively transferred tumor-reactive T cells on endogenous (host-derived) antitumor immunity

Adoptive T cell transfer therapy, the ex vivo activation, expansion, and subsequent administration of tumor-reactive T cells, is already the most effective therapy against certain types of cancer. However, recent evidence in animal models and clinical trials suggests that host conditioning interventions tailored for some of the most aggressive and frequent epithelial cancers will be needed to maximize the benefit of this approach. Similarly, the subsets, stage of differentiation, and ex vivo expansion procedure of tumor-reactive T cells to be adoptively transferred influence their in vivo effectiveness and may need to be adapted for different types of cancer and host conditioning interventions. The effects of adoptively transferred tumor-reactive T cells on the mechanisms of endogenous (host-derived) antitumor immunity, and how to maximize their combined effects, are further discussed.

The host defense peptide cathelicidin is required for NK cell-mediated suppression of tumor growth

Tumor surveillance requires the interaction of multiple molecules and cells that participate in innate and the adaptive immunity. Cathelicidin was initially identified as an antimicrobial peptide, although it is now clear that it fulfills a variety of immune functions beyond microbial killing. Recent data have suggested contrasting roles for cathelicidin in tumor development. Because its role in tumor surveillance is not well understood, we investigated the requirement of cathelicidin in controlling transplantable tumors in mice. Cathelicidin was observed to be abundant in tumor-infiltrating NK1.1(+) cells in mice. The importance of this finding was demonstrated by the fact that cathelicidin knockout mice (Camp(-/-)) permitted faster tumor growth than wild type controls in two different xenograft tumor mouse models (B16.F10 and RMA-S). Functional in vitro analyses found that NK cells derived from Camp(-/-) versus wild type mice showed impaired cytotoxic activity toward tumor targets. These findings could not be solely attributed to an observed perforin deficiency in freshly isolated Camp(-/-) NK cells, because this deficiency could be partially restored by IL-2 treatment, whereas cytotoxic activity was still defective in IL-2-activated Camp(-/-) NK cells. Thus, we demonstrate a previously unrecognized role of cathelicidin in NK cell antitumor function.

Natural killer cells require selectins for suppression of subcutaneous tumors

Natural killer (NK) cells recognize and destroy cancer cells through a variety of mechanisms. They may also modulate the adaptive immune response to cancer by interacting with dendritic cells and T cells. Although NK cells play an important role in tumor suppression, little is known about the mechanisms of their recruitment to tumors. Previously it has been shown that subcutaneous tumor growth is enhanced in mice lacking selectins, a family of cell adhesion molecules that mediate the first step of immune cell entry into tissue from the blood. Here we show that NK cell recruitment to tumors is defective in selectin-deficient mice. In vivo NK cell depletion, either pharmacologic or genetic, leads to enhanced subcutaneous tumor growth, similar to the phenotype observed in the selectin-deficient animals. We also show that although NK cells from selectin-deficient mice appear developmentally normal and are functional in in vitro assays, their in vivo function is impaired. This study reveals a role for selectins in NK cell recruitment to tumors and in regulation of effective tumor immunity.

Ligand-based targeting of apoptosis in cancer: the potential of recombinant human apoptosis ligand 2/Tumor necrosis factor-related apoptosis-inducing ligand (rhApo2L/TRAIL)

Cancer is a leading cause of premature human death and commands considerable research attention. Apoptosis (type 1 programmed cell death) is critical in maintaining tissue homeostasis in metazoan organisms, and its dysregulation underpins the initiation and progression of cancer. Conventional chemotherapy and radiotherapy can induce apoptosis as a secondary consequence of inflicting cell damage. However, more direct and selective strategies to manipulate the apoptotic process in cancer cells are emerging as potential therapeutic tools. Genetic and biochemical understanding of the cellular signaling mechanisms that control apoptosis has increased substantially during the last decade. These advances provide a strong scientific framework for developing several types of targeted proapoptotic anticancer therapies. One promising class of agents is the proapoptotic receptor agonists. Of these, recombinant human apoptosis ligand 2/tumor necrosis factor-related apoptosis-inducing ligand (rhApo2L/TRAIL)-an optimized soluble form of an endogenous apoptosis-inducing ligand-is unique in that it activates two related proapoptotic receptors, DR4 and DR5. Preclinical data indicate that rhApo2L/TRAIL can induce apoptosis in a broad range of human cancer cell lines while sparing most normal cell types. In vitro, and in various in vivo tumor xenograft models, rhApo2L/TRAIL exhibits single-agent antitumor activity and/or cooperation with certain conventional and targeted therapies. Preclinical safety studies in nonhuman primates show rhApo2L/TRAIL to be well tolerated. Moreover, early clinical trial data suggest that rhApo2L/TRAIL is generally safe and provide preliminary evidence for potential antitumor activity. Clinical studies are ongoing to assess the safety and efficacy of this novel agent in combination with established anticancer therapies.