Temporal changes in immune cell composition and cytokines in response to chemoradiation in rectal cancer

Preparation Optimization and Immunological Activity Studies of Portulaca oleracea L. Polysaccharides Liposomes

AIMS

This study combines traditional Chinese medicine polysaccharides with nanomaterials to enhance drug bioavailability and immunological activity.

BACKGROUND

The study of polysaccharide preparation, structure identification, pharmacological activity, and mechanism of action is deepening, but the research combined with the new drug delivery system is relatively weak, so the application of polysaccharides is still facing great limitations. In order to prolong the action time of polysaccharides and improve their bioavailability, liposome has become the most promising delivery carrier.

OBJECTIVES

The purpose of this study was to optimize the preparation process of Portulaca oleracea L. polysaccharides liposomes (POL-PL) and evaluate the immunoactivity in vitro.

METHODS

POL-PL was prepared by reverse evaporation, and the preparation process was optimized using the response surface methodology. The characteristic analysis of POL-PL was detected by the indicators including morphology, particle size, zeta potential, encapsulation efficiency, release, and stability. The effects of POL-PL on the proliferation and immunological activity of mouse spleen lymphocytes and RAW264.7 cells were evaluated in vitro.

RESULTS

POL-PL is highly homogeneous in morphology and particle size, and its sustained release improves the bioavailability of Portulaca oleracea L. polysaccharides (POL-P). Moreover, POL-PL treatment significantly enhanced the proliferation and phagocytic activity of RAW264.7 cells and increased the secretion of IL-6, TNF-α, IL-1β, and NO.

CONCLUSION

This study suggested that POL-PL were prepared successfully by reverse evaporation method, and POL-PL had immunoenhancing activity in vitro. The results provided a theoretical basis for further application of POL-PL.

Immune profile of patients with peritoneal carcinomatosis selected for CRS-HIPEC therapy

Cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) is a treatment option for peritoneal carcinomatosis (PC) from colorectal cancer (CRC), which is otherwise a terminal stage of disease. Nevertheless, survival outcomes are only marginally superior to other treatments. This fact highlights the need for better strategies to control intra-abdominal disease recurrence after CRS-HIPEC, including the complementary use of immunotherapies. The aim of this study was therefore to investigate the immune phenotype of T cells in patients with PC. Fifty three patients with CRC (34 patients with PC and 19 patients without PC) were enrolled in a prospective study (clinicaltrials.gov: NCT04108936). Peripheral blood and omental fat were collected to isolate peripheral blood mononuclear cells (PBMCs) and adipose tissue mononuclear cells (ATMCs). These cells were analysed by flow cytometry using a panel focused upon T cell memory differentiation and exhaustion markers. We found a more naïve profile for CD8+ T cells in peripheral blood and intra-abdominal fat of PC patients compared to comparator group (CG) patients. Furthermore, there was an over-representation of CD4+ T cells expressing inhibitory receptors in adipose tissue of PC patients, but not in blood. Our description of intraperitoneal T cell subsets gives us a better understanding of how peritoneal carcinomatosis shapes local immune responses.

Implications of Rectal Cancer Radiotherapy on the Immune Microenvironment: Allies and Foes to Therapy Resistance and Patients' Outcome

Aside from surgical resection, locally advanced rectal cancer is regularly treated with neoadjuvant chemoradiotherapy. Since the concept of cancer treatment has shifted from only focusing on tumor cells as drivers of disease progression towards a broader understanding including the dynamic tumor microenvironment (TME), the impact of radiotherapy on the TME and specifically the tumor immune microenvironment (TIME) is increasingly recognized. Both promoting as well as suppressing effects on anti-tumor immunity have been reported in response to rectal cancer (chemo-)radiotherapy and various targets for combination therapies are under investigation. A literature review was conducted searching the PubMed database for evidence regarding the pleiotropic effects of (chemo-)radiotherapy on the rectal cancer TIME, including alterations in cytokine levels, immune cell populations and activity as well as changes in immune checkpoint proteins. Radiotherapy can induce immune-stimulating and -suppressive alterations, potentially mediating radioresistance. The response is influenced by treatment modalities, including the dosage administered and the highly individual intrinsic pre-treatment immune status. Directly addressing the main immune cells of the TME, this review aims to highlight therapeutical implications since efficient rectal cancer treatment relies on personalized strategies combining conventional therapies with immune-modulating approaches, such as immune checkpoint inhibitors.

The immune microenvironment landscape shows treatment-specific differences in rectal cancer patients

Neoadjuvant therapy is the cornerstone of modern rectal cancer treatment. Insights into the biology of tumor responses are essential for the successful implementation of organ-preserving strategies, as different treatments may lead to specific tumor responses. In this study, we aim to explore treatment-specific responses of the tumor microenvironment. Patients with locally advanced adenocarcinoma of the rectum who had received neo-adjuvant chemotherapy (CT), neo-adjuvant radiochemotherapy (RCT), neo-adjuvant radiotherapy with a long-interval (LRT) or short-interval (SRT) or no neoadjuvant therapy (NT) as control were included. Multiplex-immunofluorescence was performed to determine the presence of cytotoxic T-cells (T-cyt; CD3+CD8+), regulatory T-cells (T-reg; CD3+FOXP3+), T-helper cells (T-helper; CD3+CD8-FOXP3-), B cells (CD20+), dendritic cells (CD11c+) and tumor cells (panCK+). A total of 80 rectal cancer patients were included. Treatment groups were matched for gender, tumor location, response to therapy, and TNM stage. The pattern of response (shrinkage vs. fragmentation) was, however, different between treatment groups. Our analyses reveal that RCT-treated patients exhibited lower stromal T-helper, T-reg, and T-cyt cells compared to other treatment regimens. In conclusion, we demonstrated treatment-specific differences in the immune microenvironment landscape of rectal cancer patients. Understanding the underlying mechanisms of this landscape after a specific therapy will benefit future treatment decisions.

The implications from the interplay of neoadjuvant chemoradiotherapy and the immune microenvironment in rectal cancer

Neoadjuvant chemoradiotherapy (nCRT) is recommended for the treatment of locally advanced rectal cancer. Even though the combination of nCRT and immune checkpoint inhibitors (ICIs) has received much attention, the specific combination modes and dose fractions in radiotherapy (RT) are still indistinct. This review focuses on the immunological mechanism involved in nCRT, the clinical efficacy, the immunological effect of different combined strategies, concurrent or sequential nCRT plus ICIs, long-course RT and short-course RT. This review discusses the impact of nCRT on tumor immunity and summarizes the availability of different dose fractions in RT and distinct combined strategies, aiming at providing clues for optimal neoadjuvant therapy options that maximize efficacy and minimize side effects.

Low baseline neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios predict increased overall survival in locally recurrent rectal cancer despite R1 margins

BACKGROUND

Prognostic features in locally recurrent rectal cancer (LRRC), beyond R0 surgery, are unknown.

AIMS

Aim of the present study was to evaluate the prognostic role of peripheral immune estimators, such as neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR), on survival outcomes in LRRC patients.

METHODS

184 LRRC patients treated at the National Cancer Institute of Milan (Italy) were included. Optimal cut-off values for NLR and PLR were determined. Kaplan-Meier curves and multivariate Cox analyses were used to assess the 5-yr overall survival (OS) according to NLR and PLR, also considering margins status.

RESULTS

NLR >3.9 (hazard ratio [HR] 3.96, P = 0.049), PLR >275 (HR 5.39, P = 0.002) and size on imaging (HR 1.36, P = 0.044) were associated to worse OS. R+ patients with NLR >3.9 showed a significantly lower 5-yr OS compared to NLR ≤3.9 (13.5% vs. 36.7%, P < 0.0001). Also PLR >275 was related with a lower 5-yr OS compared to PLR ≤275 in R+ patients (6.4% vs. 36.8%, P = 0.0003). Conversely, NLR and PLR were irrelevant in case of R0 surgery.

CONCLUSION

NLR and PLR predict 5-yr OS in LRRC, also identifying a subset of R+ patients with a similar expected survival compared to R0 cases.

Circulating lymphocyte subsets are prognostic factors in patients with nasopharyngeal carcinoma

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a geographically and racially variable disease that has a high incidence in Southeast China. According to previous studies on tumor immunity, we compared multiple clinical parameters and blood indexes with outcomes regarding to Epstein-Barr virus (EBV) status in NPC patients.

METHODS

According to the EBV load at diagnosis, 220 NPC patients who received concurrent chemoradiotherapy (CRT) were divided into two groups: EBV DNA ≥ 1500 copies/mL and EBV DNA < 1500 copies/mL, respectively. We compared clinical parameters with peripheral blood mononuclear cells, lymphocyte subsets and biochemical indexes. We also analyzed distant metastases and the overall survival rate regarding to these characteristics.

RESULTS

In most cases, the two groups showed the same trends. Most blood indexes were decreased during CRT and the decrease of the absolute count was more significant than the percentage. Patients with younger age showed the higher CD3+ and CD3 + CD8+ percentages. Patients whose EBV DNA ≥ 1500 copies/mL showed a higher N classification than those with EBV DNA < 1500 copies/mL at first diagnosis. Within patients with EBV DNA ≥ 1500 copies/mL, a higher CD3 + CD8+ percentage or lower CD3-CD56+ percentage had better OS rates, and the CD3 + CD8+ percentage was an independent prognostic factor by multivariate survival analyses.

CONCLUSIONS

CRT caused an overall decrease of blood cells in NPC patients. Among all the blood indexes, the CD3 + CD8+ percentage showed a correlation with age and was an independent prognostic factor in patients with EBV DNA ≥ 1500 copies/mL at first diagnosis, which is worthy for further large cohort study.

Immune profile by multiplexed immunohistochemistry associated with recurrence after chemoradiation in rectal cancer

BACKGROUND AND AIM

Evidence has emerged that a pretreatment immune profile in rectal cancer is associated with response to chemoradiotherapy (CRT) and recurrence after CRT. However, few studies have evaluated the immune profile differences after CRT regarding recurrence and nonrecurrence.

METHODS

We included patients with advanced rectal cancer treated with CRT and surgery with recurrence within 1 year in a recurrence group. After sex and age matching with the recurrence group, patients with no recurrence for 3 years after CRT were included in a nonrecurrence group. We extracted the immune profile, including CD3 and CD8, from the surgical specimen after CRT using multispectral fluorescence immunohistochemistry and compared the two groups.

RESULTS

The immune profiles of 65 patients with rectal cancer were assessed; 30 were included in the recurrence group and 35 were included in the nonrecurrence group. CD3⁺ and CD8⁺ T lymphocyte densities were significantly higher in the nonrecurrence group than in the recurrence group (CD3⁺ ; P < 0.001, CD8⁺ ; P = 0.003) in the primary tumor. Consistent results were found in epithelial and stromal cells. Compared with the recurrence group, the distinct profiles of co-expressed immune markers in the nonrecurrence group were revealed (CD3⁺ CD8⁺ , P = 0.001; CD3⁺ CD8⁺ PD-L1^- , P = 0.001; CD3⁺ CD8⁺ FOXP3^- PD-L1^- , P = 0.001).

CONCLUSIONS

Vigorous CD3⁺ and CD8⁺ T cell priming post-CRT was prominent in the nonrecurrence group compared with that of the recurrence group. This finding suggests that differences in immune profiles may have clinical significance even after CRT.

A Novel Scoring System for Response of Preoperative Chemoradiotherapy in Locally Advanced Rectal Cancer Using Early-Treatment Blood Features Derived From Machine Learning

Background

Preoperative chemoradiotherapy (CRT) is a standard treatment for locally advanced rectal cancer (LARC). However, individual responses to preoperative CRT vary from patient to patient. The aim of this study is to develop a scoring system for the response of preoperative CRT in LARC using blood features derived from machine learning.

Methods

Patients who underwent total mesorectal excision after preoperative CRT were included in this study. The performance of machine learning models using blood features before CRT (pre-CRT) and from 1 to 2 weeks after CRT (early-CRT) was evaluated. Based on the best model, important features were selected. The scoring system was developed from the selected model and features. The performance of the new scoring system was compared with those of systemic inflammatory indicators: neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, lymphocyte-to-monocyte ratio, and the prognostic nutritional index.

Results

The models using early-CRT blood features had better performances than those using pre-CRT blood features. Based on the ridge regression model, which showed the best performance among the machine learning models (AUROC 0.6322 and AUPRC 0.5965), a novel scoring system for the response of preoperative CRT, named Response Prediction Score (RPS), was developed. The RPS system showed higher predictive power (AUROC 0.6747) than single blood features and systemic inflammatory indicators and stratified the tumor regression grade and overall downstaging clearly.

Conclusion

We discovered that we can more accurately predict CRT response by using early-treatment blood data. With larger data, we can develop a more accurate and reliable indicator that can be used in real daily practices. In the future, we urge the collection of early-treatment blood data and pre-treatment blood data.

Combinations of Radiotherapy with Vaccination and Immune Checkpoint Inhibition Differently Affect Primary and Abscopal Tumor Growth and the Tumor Microenvironment

Radiotherapy (RT) is known to have immune-modulatory properties. We hypothesized that RT and inactivated whole tumor cell vaccines generated with high hydrostatic pressure (HHP) synergize to retard the tumor growth which can be additionally improved with anti-PD-1 treatment. In abscopal tumor models, we injected mice with B16-F10 melanoma or TS/A mammary tumors. To evaluate the efficiency of RT in combination with HHP vaccines, we locally irradiated only one tumor with 2 × 8 Gy or 3 × 8 Gy. HHP vaccines further retarded the growth of locally irradiated (2 × 8 Gy) tumors. However, HHP vaccination combined with RT failed to induce abscopal anti-tumor immune responses, namely those to non-irradiated tumors, and even partly abrogated those which were induced with RT plus anti-PD-1. In the latter group, the abscopal effects were accompanied by an elevated infiltration of CD8+ T cells, monocytes/macrophages, and dendritic cells. 3 × 8 Gy failed to induce abscopal effects in association with increased expression of immunosuppressive checkpoint molecules compared to 2 × 8 Gy. We conclude that HHP vaccines induce anti-tumor effects, but only if the tumor microenvironment was previously modulated by hypofractionated RT with not too many fractions, but failed to improve RT plus anti-PD-induced abscopal responses that are characterized by distinct immune alterations.

Distribution of Peripheral Blood Cells in Esophageal Cancer Patients During Concurrent Chemoradiotherapy Predicts Long-Term Locoregional Progression Hazard After Treatment (GASTO1072)

PURPOSE

Predicting the response to chemoradiotherapy is critical for the optimal management of esophageal cancer; however, it remains an unmet clinical need. This study aimed to evaluate the predictive potential of peri-treatment peripheral blood cells (PBC) in disease progression hazard in esophageal cancer following chemoradiotherapy.

PATIENTS AND METHODS

A total of 87 patients with primary esophageal squamous cell carcinoma were subjected to definitive concurrent chemoradiotherapy in a Phase II trial. PBC parameters (hemoglobin, neutrophils, platelets, lymphocytes, and monocytes) were collected at seven time points throughout the course of radiotherapy. The potential of peri-treatment PBC parameters to predict the 3-year cumulative hazard of tumor progression was evaluated.

RESULTS

Patients with disease progression displayed distinct distribution patterns of peri-treatment PBC compared to that in patients without disease progression. Greater prediction capabilities for risk of locoregional disease progression were found in PBC collected after the start of radiotherapy compared to those in their pretreatment counterparts, and in individual parameters rather than cell-to-cell ratios. The most predictive PBC parameters were integrated by summation and designated as a PBC score (PBCS), which further augmented their predictive power. Patients classified according to their PBCS (high vs medium v. low) had significantly different 3-year cumulative hazards of locoregional progression (58% vs 29% vs 7%, P = 0.0017). Multivariate analysis confirmed that high PBCS (HR, 12.2; 95% CI, 2.0-76.3; P = 0.007) and medium (HR, 5.8; 95% CI 1.2-27.7; P = 0.028) were independent indicators of locoregional progression.

CONCLUSION

Systematic analysis of PBC distribution in esophageal cancer patients undergoing definitive chemoradiotherapy could help predict long-term locoregional progression hazard after treatment.

Neutrophil-to-Lymphocyte Ratio in Rectal Cancer-Novel Biomarker of Tumor Immunogenicity During Radiotherapy or Confounding Variable?

The aim of this study was to investigate the predictive value of blood-derived makers of local and systemic inflammatory responses on early and long-term oncological outcomes. A retrospective analysis of patients with locally advanced rectal cancer treated with preoperative long-course 5-fluorouracil-based radiochemotherapy was performed. Differential blood counts before neoadjuvant treatment were extracted from the patients' electronic charts. Optimal cut-off values for neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR) were determined. Potential clinical and hematological prognostic factors for disease-free survival (DFS) were studied using uni- and multivariate analysis. A total of 220 patients were included in the analysis. Median follow-up was 67 months. Five-year DFS and overall survival (OS) were 70% and 85%, respectively. NLR with a cut-off value of 4.06 was identified as optimal to predict DFS events. In multivariate analysis, only tumor volume (HR 0.33, 95% CI (0.14-0.83), p = 0.017) and NLR (HR 0.3, 95% CI (0.11-0.81), p = 0.017) remained significant predictors of DFS. Patients with a good histological response (Dworak 3 and 4) to radiotherapy also had a lower NLR than patients with less pronounced tumor regression (3.0 vs. 4.2, p = 0.015). A strong correlation between primary tumor volume and NLR was seen (Pearson's r = 0.64, p < 0.001). Moreover, patients with T4 tumors had a significantly higher NLR than patients with T1-T3 tumors (6.6 vs. 3.3, p < 0.001). An elevated pretherapeutic NLR was associated with higher T stage, inferior DFS, and poor pathological response to neoadjuvant radiochemotherapy. A strong correlation between NLR and primary tumor volume was seen. This association is important for the interpretation of study results and for the design of translational studies which are warranted.

Dissecting intratumoral myeloid cell plasticity by single cell RNA-seq

Tumor‐infiltrating myeloid cells are the most abundant leukocyte population within tumors. Molecular cues from the tumor microenvironment promote the differentiation of immature myeloid cells toward an immunosuppressive phenotype. However, the in situ dynamics of the transcriptional reprogramming underlying this process are poorly understood. Therefore, we applied single cell RNA‐seq (scRNA‐seq) to computationally investigate the cellular composition and transcriptional dynamics of tumor and adjacent normal tissues from 4 early‐stage non‐small cell lung cancer (NSCLC) patients. Our scRNA‐seq analyses identified 11 485 cells that varied in identity and gene expression traits between normal and tumor tissues. Among these, myeloid cell populations exhibited the most diverse changes between tumor and normal tissues, consistent with tumor‐mediated reprogramming. Through trajectory analysis, we identified a differentiation path from CD14+ monocytes to M2 macrophages (monocyte‐to‐M2). This differentiation path was reproducible across patients, accompanied by increased expression of genes (eg, MRC1/CD206, MSR1/CD204, PPARG, TREM2) with significantly enriched functions (Oxidative phosphorylation and P53 pathway) and decreased expression of genes (eg, CXCL2, IL1B) with significantly enriched functions (TNF‐α signaling via NF‐κB and inflammatory response). Our analysis further identified a co‐regulatory network implicating upstream transcription factors (JUN, NFKBIA) in monocyte‐to‐M2 differentiation, and activated ligand‐receptor interactions (eg, SFTPA1‐TLR2, ICAM1‐ITGAM) suggesting intratumoral mechanisms whereby epithelial cells stimulate monocyte‐to‐M2 differentiation. Overall, our study identified the prevalent monocyte‐to‐M2 differentiation in NSCLC, accompanied by an intricate transcriptional reprogramming mediated by specific transcriptional activators and intercellular crosstalk involving ligand‐receptor interactions.

Prognostic impact of persistent lower neutrophil-to-lymphocyte ratio during preoperative chemoradiotherapy in locally advanced rectal cancer patients: A propensity score matching analysis

Purpose

This study investigated the significance of change in neutrophil-to-lymphocyte ratio (NLR) during preoperative chemoradiotherapy (preop-CRT) in patients with non-metastatic rectal cancer using a propensity score matching method (PSM).

Methods

Patients who underwent surgery after completion of preop-CRT for non-metastatic rectal cancers from Jan 2004 to Dec 2013 were retrospectively enrolled. NLRs were obtained before commencement of CRT (pre-NLR) and between completion of CRT and surgery (post-NLR). Using Cox regression hazards models, the association of NLRs with survival after PSM was examined.

Results

A total of 131 patients were grouped as follows: group A, pre-NLR < 3 & post-NLR < 3 (n = 47); group B, pre-NLR < 3 & post-NLR ≥ 3 (n = 45); group C, pre-NLR ≥ 3 & post-NLR < 3 (n = 5); group D, pre-NLR ≥ 3 & post-NLR ≥ 3 (n = 34). There was no difference in disease-free survival (DFS) or overall survival (OS) rate according to group. When dichotomized into group A versus groups B-D, DFS was higher in group A (84.7%) than groups B-D (67.5%, p = 0.021). After PSM (n = 94), multivariable analysis identified persistent lower NLR as an independent favorable prognosticator of DFS (HR 0.37, 95% CI 0.15–0.92, p = 0.033).

Conclusions

Persistent non-inflammatory state measured by NLR may be an indicator of decreased risk of recurrence in patients with locally advanced rectal cancer treated with preop-CRT.