Interferon-Induced IDO1 Mediates Radiation Resistance and Is a Therapeutic Target in Colorectal Cancer

Nanodelivery Optimization of IDO1 Inhibitors in Tumor Immunotherapy: Challenges and Strategies

Tryptophan (Trp) metabolism plays a vital role in cancer immunity. Indoleamine 2.3-dioxygenase 1 (IDO1), is a crucial enzyme in the metabolic pathway by which Trp is degraded to kynurenine (Kyn). IDO1-mediated Trp metabolites can inhibit tumor immunity and facilitate immune evasion by cancer cells; thus, targeting IDO1 is a potential tumor immunotherapy strategy. Recently, numerous IDO1 inhibitors have been introduced into clinical trials as immunotherapeutic agents for cancer treatment. However, drawbacks such as low oral bioavailability, slow onset of action, and high toxicity are associated with these drugs. With the continuous development of nanotechnology, medicine is gradually entering an era of precision healthcare. Nanodrugs carried by inorganic, lipid, and polymer nanoparticles (NPs) have shown great potential for tumor therapy, providing new ways to overcome tumor diversity and improve therapeutic efficacy. Compared to traditional drugs, nanomedicines offer numerous significant advantages, including a prolonged half-life, low toxicity, targeted delivery, and responsive release. Moreover, based on the physicochemical properties of these nanomaterials (eg, photothermal, ultrasonic response, and chemocatalytic properties), various combination therapeutic strategies have been developed to synergize the effects of IDO1 inhibitors and enhance their anticancer efficacy. This review is an overview of the mechanism by which the Trp-IDO1-Kyn pathway acts in tumor immune escape. The classification of IDO1 inhibitors, their clinical applications, and barriers for translational development are discussed, the use of IDO1 inhibitor-based nanodrug delivery systems as combination therapy strategies is summarized, and the issues faced in their clinical application are elucidated. We expect that this review will provide guidance for the development of IDO1 inhibitor-based nanoparticle nanomedicines that can overcome the limitations of current treatments, improve the efficacy of cancer immunotherapy, and lead to new breakthroughs in the field of cancer immunotherapy.

A computational pipeline for identifying gene targets and signalling pathways in cancer cells to improve lymphocyte infiltration and immune checkpoint therapy efficacy

BACKGROUND

Tumour-infiltrating lymphocytes (TILs) are crucial for effective immune checkpoint blockade (ICB) therapy in solid tumours. However, ∼70% of these tumours exhibit poor lymphocyte infiltration, rendering ICB therapies less effective.

METHODS

We developed a bioinformatics pipeline integrating multiple previously unconsidered factors or datasets, including tumour cell immune-related pathways, copy number variation (CNV), and single tumour cell sequencing data, as well as tumour mRNA-seq data and patient survival data, to identify targets that can potentially improve T cell infiltration and enhance ICB efficacy. Furthermore, we conducted wet-lab experiments and successfully validated one of the top-identified genes.

FINDINGS

We applied this pipeline in solid tumours of the Cancer Genome Atlas (TCGA) and identified a set of genes in 18 cancer types that might potentially improve lymphocyte infiltration and ICB efficacy, providing a valuable drug target resource to be further explored. Importantly, we experimentally validated SUN1, which had not been linked to T cell infiltration and ICB therapy previously, but was one of the top-identified gene targets among 3 cancer types based on the pipeline, in a mouse colon cancer syngeneic model. We showed that Sun1 KO could significantly enhance antigen presentation, increase T-cell infiltration, and improve anti-PD1 treatment efficacy. Moreover, with a single-cell multiome analysis, we identified subgene regulatory networks (sub-GRNs) showing Stat proteins play important roles in enhancing the immune-related pathways in Sun1-KO cancer cells.

INTERPRETATION

This study not only established a computational pipeline for discovering new gene targets and signalling pathways in cancer cells that block T-cell infiltration, but also provided a gene target pool for further exploration in improving lymphocyte infiltration and ICB efficacy in solid tumours.

FUNDING

A full list of funding bodies that contributed to this study can be found in the Acknowledgements section.

TOPK Inhibition Enhances the Sensitivity of Colorectal Cancer Cells to Radiotherapy by Reducing the DNA Damage Response

OBJECTIVE

Abnormal expression of T-lymphokine-activated killer cell-originated protein kinase (TOPK) was reported to be closely related to the resistance of prostate cancer to radiotherapy and to targeted drug resistance in lung cancer. However, the role of TOPK inhibition in enhancing radiosensitivity of colorectal cancer (CRC) cells is unclear. This study aimed to evaluate the radiosensitization of TOPK knockdown in CRC cells.

METHODS

The expression of TOPK was detected in CRC tissues by immunohistochemistry, and the effect of TOPK knockdown was detected in CRC cells by Western blotting. CCK-8 and clonogenic assays were used to detect the growth and clonogenic ability of CRC cells after TOPK knockdown combined with radiotherapy in CRC cells. Furthermore, proteomic analysis showed that the phosphorylation of TOPK downstream proteins changed after radiotherapy. DNA damage was detected by the comet assay. Changes in the DNA damage response signaling pathway were analyzed by Western blotting, and apoptosis was detected by flow cytometry.

RESULTS

The expression of TOPK was significantly greater in CRC tissues at grades 2-4 than in those at grade 1. After irradiation, CRC cells with genetically silenced TOPK had shorter comet tails and reduced expression levels of DNA damage response-associated proteins, including phospho-cyclin-dependent kinase 1 (p-CDK1), phospho-ataxia telangiectasia-mutated (p-ATM), poly ADP-ribose polymerase (PARP), and meiotic recombination 11 homolog 1 (MRE11).

CONCLUSIONS

TOPK was overexpressed in patients with moderately to poorly differentiated CRC. Moreover, TOPK knockdown significantly enhanced the radiosensitivity of CRC cells by reducing the DNA damage response.

The effects of metabolism on the immune microenvironment in colorectal cancer

Colorectal cancer (CRC) is a malignancy that is widely prevalent worldwide. Due to its unsatisfactory treatment outcome and extremely poor prognosis, many studies on the molecular mechanisms and pathological mechanisms of CRC have been published in recent years. The tumor microenvironment (TME) is an extremely important feature of tumorigenesis and one of the hallmarks of tumor development. Metabolic reprogramming is currently a hot topic in tumor research, and studies on this topic have provided important insights into CRC development. In particular, metabolic reprogramming in cancer causes changes in the composition of energy and nutrients in the TME. Furthermore, it can alter the complex crosstalk between immune cells and associated immune factors, such as associated macrophages and T cells, which play important immune roles in the TME, in turn affecting the immune escape of tumors by altering immune surveillance. In this review, we summarize several metabolism-related processes affecting the immune microenvironment of CRC tumors. Our results showed that the immune microenvironment is regulated by metabolic reprogramming and influences the development of CRC.

Radiation dose, schedule, and novel systemic targets for radio-immunotherapy combinations

Immunotherapy combinations are being investigated to expand the benefit of immune checkpoint blockade across many cancer types. Radiation combinations, in particular using stereotactic body radiotherapy, are of keen interest because of underlying mechanistic rationale, safety, and availability as a standard of care in certain cancers. In addition to direct tumor cytotoxicity, radiation therapy has immunomodulatory effects such as induction of immunogenic cell death, enhancement of antigen presentation, and expansion of the T-cell receptor repertoire as well as recruitment and increased activity of tumor-specific effector CD8+ cells. Combinations of radiation with cytokines and/or chemokines and anti-programmed death 1 and anticytotoxic T-lymphocyte antigen 4 therapies have demonstrated safety and feasibility, as well as the potential to improve long-term outcomes and possibly induce out of irradiated field or abscopal responses. Novel immunoradiotherapy combinations represent a promising therapeutic approach to overcome radioresistance and further enhance systemic immunotherapy. Potential benefits include reversing CD8+ T-cell exhaustion, inhibiting myeloid-derived suppressor cells, and reversing M2 macrophage polarization as well as decreasing levels of colony-stimulating factor-1 and transforming growth factor-β. Here, we discuss current data and mechanistic rationale for combining novel immunotherapy agents with radiation therapy.

Development and validation of prognostic nomograms for early-onset colon cancer in different tumor locations: a population-based study

OBJECTIVE

The prevalence of early-onset colon cancer (EOCC) among individuals below the age of 50 has shown a marked upward trend in recent years. The embryology, clinical symptoms, incidence, molecular pathways, and oncologic outcomes differ between right-sided and left-sided colon cancers. However, the differences have not been fully researched in EOCC. Our study aims to develop and validate prognostic nomograms predicting overall survival (OS) and cancer-specific survival (CSS) for EOCC in different tumor locations based on the Surveillance, Epidemiology, and End Results (SEER) database.

METHODS

Using the SEER database, a total of 5,588 patients with EOCC were extracted and divided into development and validation cohorts in a random allocation ratio of 7:3 across three groups. Univariate and multivariate Cox regression analyses were performed to identify independent prognostic factors influencing OS and CSS outcomes. These factors were then utilized to construct nomogram models. The prognostic capabilities of the three models were assessed through various evaluation metrics, including the concordance index (C-index), receiver operating characteristic (ROC) curves, calibration curves, decision curve analysis (DCA), and validation cohorts respectively. Additionally, survival curves of the low- and high-risk groups were calculated using the Kaplan-Meier method together with the log-rank test.

RESULTS

Significant differences in clinical features were observed between right-sided and left-sided EOCCs, particularly in terms of OS (52 months vs 54 months) as demonstrated by Kaplan-Meier curves. Transverse-sided EOCCs exhibited clinical characteristics similar to right-sided EOCCs, suggesting a potential shared tumor microenvironment and therapeutic considerations. Advanced stage, liver metastasis, poor grade, elevated pretreatment carcinoembryonic antigen (CEA) level, chemotherapy, and perineural invasion were identified as independent prognostic factors across all three tumor locations and were incorporated into the nomogram model. Nomograms were constructed to predict the probability of 3- and 5-year OS and CSS. The C-index and calibration plots showed that the established nomograms had good consistency between actual clinical observations and predicted outcomes. ROC curves with calculated area under the curve (AUC) values exceeded 0.8 for all three groups in both the development and validation cohorts, indicating robust predictive performance for OS and CSS. Furthermore, decision curve analysis (DCA) plots revealed a threshold probability range of 0.1 to 0.9, within which the nomogram model exhibited maximum benefit. Kaplan-Meier curves exhibited significant differences between the low- and high-risk groups in EOCC for all three tumor locations in OS and CSS, further validating the prognostic value of the nomogram models.

CONCLUSIONS

We successfully developed three precise nomogram models for EOCCs in different tumor locations, providing valuable support for clinicians in guiding clinical treatments and facilitating further prospective follow-up studies.

Radionuclide-Labeled Microspheres for Radio-Immunotherapy of Hepatocellular Carcinoma

Brachytherapy, including radioactive seed implantation (RSI) and transarterial radiation therapy embolization (TARE), is an important treatment modality for advanced hepatocellular carcinoma (HCC), but the inability of RSI and TARE to treat tumor metastasis and recurrence limits their benefits for patients in the clinic. Herein, indoleamine 2,3-dioxygenase 1 (IDO1) inhibitors-loaded alginate microspheres (IMs) are developed as radionuclide carriers with immunomodulatory functions to achieve effective radio-immunotherapy. The size and swelling properties of IMs can be facilely tailored by adjusting the calcium source during emulsification. Small/large IMs(SIMs/LIMs) are biocompatible and available for RSI and TARE, respectively, after 177 Lu labeling. Among them, 177 Lu-SIMs completely eliminated subcutaneous HCC in mice after intratumoral RSI. Moreover, in combination with anti-PD-L1, 177 Lu-SIMs not only eradicate primary tumors by RSI but also effectively inhibit the growth of distant tumors, wherein the potent abscopal effect can be ascribed to the immune stimulation of RSI and the modulation of the tumor immune microenvironment (TIME) by IDO1 inhibitors. In parallel, LIMs demonstrate excellent embolization efficiency, resulting in visible necrotic lesions in the central auricular artery of rabbits, which are promising for TARE in future studies. Collectively, a versatile therapeutic agent is provided to synchronously modulate the TIME during brachytherapy for efficient radio-immunotherapy of advanced HCC.

Triplet regimen as a novel modality for advanced unresectable hepatocellular carcinoma: A case report and review of literature

BACKGROUND

Portal vein tumor thrombus (PVTT) is a common complication, accounting for 44%-62.2% of Hepatocellular carcinoma (HCC), and often indicates the poor prognosis. There is no global consensus for the treatment of unresectable HCC with PVTT. In the present case, we reported a novel strategy of radiotherapy-antiangiogenesis-immune checkpoint blockade combination, which showed better response and prolonged survival.

CASE SUMMARY

A 51-year-old male diagnosed with HCC (Child-Pugh class A), chronic hepatitis B virus infection and Cheng's type III PVTT, was given radiotherapy to part of the lesion plus targeted therapy as the first-line therapy, and achieved partial remission. After radiotherapy, lenvatinib plus pembrolizumab was used as maintenance therapy, and complete remission was achieved. The patient remains alive 46 months after the diagnosis of the HCC with PVTT.

CONCLUSION

This case of unresectable HCC patient with PVTT treated by radiation-lenvatinib-pembrolizumab combination therapy shows apparent clinical efficacy, which demonstrates that local radiotherapy plus antiangiogenesis and immune checkpoint blockad could also benefit patients with advanced HCC.

Immunologic constant of rejection as a predictive biomarker of immune checkpoint inhibitors efficacy in non-small cell lung cancer

BACKGROUND

Anti-PD1/PDL1 immune checkpoint inhibitors (ICI) transformed the prognosis of patients with advanced non-small cell lung cancer (NSCLC). However, the response rate remains disappointing and toxicity may be life-threatening, making urgent identification of biomarkers predictive for efficacy. Immunologic Constant of Rejection signature (ICR) is a 20-gene expression signature of cytotoxic immune response with prognostic value in some solid cancers. Our objective was to assess its predictive value for benefit from anti-PD1/PDL1 in patients with advanced NSCLC.

METHODS

We retrospectively profiled 44 primary tumors derived from NSCLC patients treated with ICI as single-agent in at least the second-line metastatic setting. Transcriptomic analysis was performed using the nCounter® analysis system and the PanCancer Immune Profiling Panel. We then pooled our data with clinico-biological data from four public gene expression data sets, leading to a total of 162 NSCLC patients treated with single-agent anti-PD1/PDL1. ICR was applied to all samples and correlation was searched between ICR classes and the Durable Clinical Benefit (DCB), defined as stable disease or objective response according to RECIST 1.1 for a minimum of 6 months after the start of ICI.

RESULTS

The DCB rate was 29%; 22% of samples were classified as ICR1, 30% ICR2, 22% ICR3, and 26% ICR4. These classes were not associated with the clinico-pathological variables, but showed enrichment from ICR1 to ICR4 in quantitative/qualitative markers of immune response. ICR2-4 class was associated with a 5.65-fold DCB rate when compared with ICR1 class. In multivariate analysis, ICR classification remained associated with DCB, independently from PDL1 expression and other predictive immune signatures. By contrast, it was not associated with disease-free survival in 556 NSCLC TCGA patients untreated with ICI.

CONCLUSION

The 20-gene ICR signature was independently associated with benefit from anti-PD1/PDL1 ICI in patients with advanced NSCLC. Validation in larger retrospective and prospective series is warranted.

Verification of fasting-mimicking diet to assist monotherapy of human cancer-bearing models

The efficacy of a single clinical nanodrug for cancer treatment is still unsatisfactory, especially for drug-resistant cancer. Herein, we applied a fasting-mimicking diet (FMD) approach via dietary intervention to assist single clinical nanodrug for breast or ovarian cancer treatments instead of using multi-drug therapies which might cause adverse side effects. Specifically, we adopted Doxil or Abraxane to treat human breast tumor-bearing nude mice and Doxil to treat the human ovarian tumor and drug-resistant ovarian tumor-bearing nude mice under FMD conditions, respectively. According to the results, the FMD condition can promote the cellular uptake and cytotoxicity of a single nanodrug, reduce the ATP level in drug-resistant tumor cells to hinder drug efflux, normalize tumor blood vessels, relieve tumor hypoxia, and increase the accumulation of nanodrugs at tumor sites, thereby enhancing the therapeutic effects on these types of human cancers. Collectively, these results demonstrate that the FMD strategy of significance can become a practical, alternative, and promising assistant for single nanodrug for enhancing cancer therapy and clinical translation.

Abnormal kynurenine-pathway metabolites in gout: Biomarkers exploration based on orthogonal partial least squares-discriminant analysis

BACKGROUND

This study aims to investigate serological characteristics of kynurenine pathway (KP) metabolites in healthy controls (HC) and gout patients and explore possible differential metabolites.

METHODS

A total of 191 individual fresh residual sera was collected from 129 HC and 62 gout patients. A liquid chromatography-tandem mass spectrometry method was fully validated to measure 6 metabolites, including tryptophan (TRP), kynurenine (KYN), 5-hydroxytryptamine (5HT), kynurenic acid (KA), xanthurenic acid (XA), and neopterin (NEO). Supervised orthogonal partial least squares-discriminant analysis (OPLS-DA) and differential metabolite screening with fold change (FC) were performed to identify intrinsic variations and differential levels of KP metabolites between the HC and gout groups. Logistic regression was used to assess the contributions of KP metabolites to gout.

RESULTS

There were significant decreases of TRP, 5HT, XA, and NEO and increases of KYN, KA, KA/KYN, and KYN/TRP in gout patients compared to the HC group (all p < 0.05). KP metabolites of the gout group showed good discrimination from those of the HC group (Q2: 0.892). Two distinct different metabolites were identified in gout, i.e., XA (FC: 0.56, p < 0.01) and NEO (FC: 0.34, p < 0.01). Of the KP metabolites, KYN was strongly associated with gout (OR: 7.91, p < 0.01).

CONCLUSIONS

Abnormal levels of serum KP metabolites were observed in gout. XA and NEO are promising biomarkers that were relevant to the status of gout. The level of KYN could be an attractive checkpoint for the management of gout. Continuous monitoring of KP metabolism in gout provides new opportunities to predict therapeutic efficacy and prognosis.

Exploring novel genetic and hematological predictors of response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer

Introduction: The standard treatment for locally advanced rectal cancer (LARC) is neoadjuvant chemoradiotherapy (nCRT). To select patients who would benefit the most from nCRT, there is a need for predictive biomarkers. The aim of this study was to evaluate the role of clinical, pathological, radiological, inflammation-related genetic, and hematological parameters in the prediction of post-nCRT response. Materials and methods: In silico analysis of published transcriptomics datasets was conducted to identify candidate genes, whose expression will be measured using quantitative Real Time PCR (qRT-PCR) in pretreatment formaline-fixed paraffin-embedded (FFPE) samples. In this study, 75 patients with LARC were prospectively included between June 2020-January 2022. Patients were assessed for tumor response in week 8 post-nCRT with pelvic MRI scan and rigid proctoscopy. For patients with a clinical complete response (cCR) and initially distant located tumor no immediate surgery was suggested ("watch and wait" approach). The response after surgery was assessed using histopathological tumor regression grading (TRG) categories from postoperative specimens by Mandard. Responders (R) were defined as patients with cCR without operative treatment, and those with TRG 1 and TRG 2 postoperative categories. Non-responders (NR) were patients classified as TRG 3-5. Results: Responders group comprised 35 patients (46.6%) and NR group 53.4% of patients. Analysis of published transcriptomics data identified genes that could predict response to treatment and their significance was assessed in our cohort by qRT-PCR. When comparison was made in the subgroup of patients who were operated (TRG1 vs. TRG4), the expression of IDO1 was significantly deregulated (p < 0.05). Among hematological parameters between R and NR a significant difference in the response was detected for neutrophil-to-monocyte ratio (NMR), initial basophil, eosinophil and monocyte counts (p < 0.01). According to MRI findings, non-responders more often presented with extramural vascular invasion (p < 0.05). Conclusion: Based on logistic regression model, factors associated with favorable response to nCRT were tumor morphology and hematological parameters which can be easily and routinely derived from initial laboratory results (NMR, eosinophil, basophil and monocyte counts) in a minimally invasive manner. Using various metrics, an aggregated score of the initial eosinophil, basophil, and monocyte counts demonstrated the best predictive performance.

YWHAZ and TBP are potential reference gene candidates for qPCR analysis of response to radiation therapy in colorectal cancer

The expression profiles of conventional reference genes (RGs), including ACTB and GAPDH, used in quantitative real-time PCR (qPCR), vary depending on tissue types and environmental conditions. We searched for suitable RGs for qPCR to determine the response to radiotherapy in colorectal cancer (CRC) cell lines, organoids, and patient-derived tissues. Ten CRC cell lines (Caco-2, COLO 205, DLD-1, HCT116, HCT-15, HT-29, RKO, SW1116, SW480, and SW620) and organoids were selected and irradiated with 2, 10 or 21 grays (Gy) based on the previous related studies conducted over the last decade. The expression stability of 14 housekeeping genes (HKGs; ACTB, B2M, G6PD, GAPDH, GUSB, HMBS, HPRT1, IPO8, PGK1, PPIA, TBP, TFRC, UBC, and YWHAZ) after irradiation was evaluated using RefFinder using raw quantification cycle (Cq) values obtained from samples before and after irradiation. The expression stability of HKGs were also evaluated for paired fresh frozen tissues or formalin-fixed, paraffin-embedded samples obtained from CRC patients before and after chemoradiotherapy. The expression of YWHAZ and TBP encoding 14-3-3-zeta protein and TATA-binding protein were more stable than the other 12 HKGs in CRC cell lines, organoids, and patient-derived tissues after irradiation. The findings suggest that YWHAZ and TBP are potential RG candidates for normalizing qPCR results in CRC radiotherapy experiments.

Exploring the immune microenvironment in small bowel adenocarcinoma using digital image analysis

BACKGROUND

Small bowel adenocarcinoma (SBA) is a rare malignancy of the small intestine associated with late stage diagnosis and poor survival outcome. High expression of immune cells and immune checkpoint biomarkers especially programmed cell death ligand-1 (PD-L1) have been shown to significantly impact disease progression. We have analysed the expression of a subset of immune cell and immune checkpoint biomarkers in a cohort of SBA patients and assessed their impact on progression-free survival (PFS) and overall survival (OS).

METHODS

25 patient samples in the form of formalin fixed, paraffin embedded (FFPE) tissue were obtained in tissue microarray (TMAs) format. Automated immunohistochemistry (IHC) staining was performed using validated antibodies for CD3, CD4, CD8, CD68, PD-L1, ICOS, IDO1 and LAG3. Slides were scanned digitally and assessed in QuPath, an open source image analysis software, for biomarker density and percentage positivity. Survival analyses were carried out using the Kaplan Meier method.

RESULTS

Varying expressions of biomarkers were recorded. High expressions of CD3, CD4 and IDO1 were significant for PFS (p = 0.043, 0.020 and 0.018 respectively). High expression of ICOS was significant for both PFS (p = 0.040) and OS (p = 0.041), while high PD-L1 expression in tumour cells was significant for OS (p = 0.033). High correlation was observed between PD-L1 and IDO1 expressions (Pearson correlation co-efficient = 1) and subsequently high IDO1 expression in tumour cells was found to be significant for PFS (p = 0.006) and OS (p = 0.034).

CONCLUSIONS

High levels of immune cells and immune checkpoint proteins have a significant impact on patient survival in SBA. These data could provide an insight into the immunotherapeutic management of patients with SBA.

Macrophage's role in solid tumors: two edges of a sword

The tumor microenvironment is overwhelmingly dictated by macrophages, intimately affiliated with tumors, exercising pivotal roles in multiple processes, including angiogenesis, extracellular matrix reconfiguration, cellular proliferation, metastasis, and immunosuppression. They further exhibit resilience to chemotherapy and immunotherapy via meticulous checkpoint blockades. When appropriately stimulated, macrophages can morph into a potent bidirectional component of the immune system, engulfing malignant cells and annihilating them with cytotoxic substances, thus rendering them intriguing candidates for therapeutic targets. As myelomonocytic cells relentlessly amass within tumor tissues, macrophages rise as prime contenders for cell therapy upon the development of chimeric antigen receptor effector cells. Given the significant incidence of macrophage infiltration correlated with an unfavorable prognosis and heightened resistance to chemotherapy in solid tumors, we delve into the intricate role of macrophages in cancer propagation and their promising potential in confronting four formidable cancer variants-namely, melanoma, colon, glioma, and breast cancers.

Progress of regulatory RNA in small extracellular vesicles in colorectal cancer

Colorectal cancer (CRC) is the second most common malignant tumor of the gastrointestinal tract with the second highest mortality rate and the third highest incidence rate. Early diagnosis and treatment are important measures to reduce CRC mortality. Small extracellular vesicles (sEVs) have emerged as key mediators that facilitate communication between tumor cells and various other cells, playing a significant role in the growth, invasion, and metastasis of cancer cells. Regulatory RNAs have been identified as potential biomarkers for early diagnosis and prognosis of CRC, serving as crucial factors in promoting CRC cell proliferation, invasion and metastasis, angiogenesis, drug resistance, and immune cell differentiation. This review provides a comprehensive summary of the vital role of sEVs as biomarkers in CRC diagnosis and their potential application in CRC treatment, highlighting their importance as a promising avenue for further research and clinical translation.

Research progress of STAT3-based dual inhibitors for cancer therapy

Signal transducer and activator of transcription 3 (STAT3), a transcription factor, regulates gene levels that are associated with cell survival, cell cycle, and immune reaction. It is correlated with the grade of malignancy and the development of various cancers and targeting STAT3 protein is a potentially promising therapeutic strategy for tumors. Over the past 20 years, various compounds have been found to directly inhibit STAT3 activity via different strategies. However, numerous difficulties exist in the development of STAT3 inhibitors, such as serious toxic effects, poor therapeutic effects, and intrinsic and acquired drug resistance. STAT3 inhibitors synergistically suppress cancer development with additional anti-tumor drugs, such as indoleamine 2,3-dioxygenase 1 inhibitors (IDO1i), histone deacetylase inhibitors (HDACi), DNA inhibitors, pro-tumorigenic cytokine inhibitors (PTCi), NF-κB inhibitors, and tubulin inhibitors. Therefore, individual molecule- based dual-target inhibitors can be the candidate alternative or complementary treatment to overcome the disadvantages of just STAT3 or other targets as a monotherapy. In this review, we discuss the theoretical basis for formulating STAT3-based dual-target inhibitors and also summarize their structure-activity relationships (SARs).

Indoleamine 2,3-Dioxygenase as a Therapeutic Target for Alzheimer's Disease and Geriatric Depression

Neuroimmune-triggered neuroinflammation of the central nervous system is emerging as an important aetiopathogenic factor for multiple neurological disorders, including depression, dementia, Alzheimer's disease, multiple sclerosis and others. Tryptophan metabolism via the kynurenic pathway, which is initiated by the indoleamine-2,3-dioxygenase (IDO-1) enzyme, is a key regulator of the neuroimmune system and its associated neuroinflammatory effects. As discussed in this review, targeting the production of immunopathic and potentially neurotoxic kynurenine metabolites by inhibitory downregulation of IDO-1 may prove a viable target against inflammation-induced neurological conditions, particularly depression and dementia.

IDO1/COX2 Expression Is Associated with Poor Prognosis in Colorectal Cancer Liver Oligometastases

Background: IDO1 and COX2 have emerged as promising immunotherapy targets. It is unclear whether IDO1 and COX2 expression levels in colorectal cancer (CRC) patients with liver oligometastases could be independent predictors of overall survival (OS) and progression-free survival (PFS). The purpose of this study was to investigate the correlation of IDO1 and COX2 expression levels with OS and PFS in CRC patients with liver oligometastases. Methods: The expression levels of IDO1 and COX2 were assessed by immunohistochemistry in 107 specimens from patients with liver oligometastases. The correlation between the expression of IDO1 and COX2 and the clinicopathological parameters and OS/PFS in patients was examined. Results: The expression level of IDO1/COX2 was significantly correlated with age and was not associated with gender, BMI, T stage, N stage, primary tumor size, liver metastasis size, CEA, CA19-9, CD3 TILs or CD8 TILs. In univariate analysis, we found that IDO1/COX2 expression, CEA and N stage all yielded significantly poor OS and PFS outcomes. In our multivariate Cox model, IDO1/COX2 coexpression, CEA and N stage were found to be significantly correlated with OS; IDO1/COX2 coexpression and CEA were significantly correlated with PFS. Conclusions: IDO1/COX2 coexpression plays a pivotal role and may act as a potential prognostic biomarker for survival in CRC patients with liver oligometastases.

Sertaconazole nitrate targets IDO1 and regulates the MAPK signaling pathway to induce autophagy and apoptosis in CRC cells

Colorectal cancer (CRC) has become the third most frequently occurring malignant tumor worldwide. It is vital to identify novel, effective targeted treatments while considering side effects and drug resistance in the clinic. Recently, the tryptophan-metabolizing enzyme indole-2, 3-dioxygenase 1 (IDO1) has been widely reported to be overexpressed in CRC, indicating that blocking IDO1 with small-molecule inhibitors may be a promising approach to CRC treatment. In this study, the antifungal drug sertaconazole nitrate (STZ) was repurposed and showed antitumor activity, and therefore, its anticancer effect was further investigated in CRC cells. The SwissTargetPrediction analysis indicated that STZ binding to IDO1 was significantly and highly probable, and STZ was found to downregulate IDO1 in CRC cells in a dose-dependent manner. STZ exhibited considerable antiproliferative activity and induced apoptosis and autophagy in HCT116 and RKO cells. Moreover, based on an RNA-seq analysis, STZ was shown to regulate signal transducer and activator of transcription 3 (STAT3) and the mitogen-activated protein kinase (MAPK) signaling pathways. We discovered that STZ suppressed tumor growth in an HCT116 nude mouse xenograft tumor model without causing evident cytotoxicity. In conclusion, our results reveal that STZ induces antitumor effects in CRC by inhibiting IDO1-modulated autophagy and apoptosis, providing a clue for repurposing STZ as a novel and potentially effective candidate medication for the future treatment of CRC.

IDO1 Activity Predicts Lung Toxicity in Patients with Unresectable Stage III NSCLC and Chemoradiotherapy

Objectives

Indoleamine 2,3-dioxygenase 1 (IDO1) acts as the key rate-limiting enzyme that converts tryptophan (Trp) to kynurenine (Kyn). Its activity was primarily induced by interferon-γ (IFN-γ), which was reported to play a role in the development of acute radiation-induced pneumonitis. In this study, we aimed to investigate the correlation between IDO1 activity and radiation-induced lung toxicity (RILT) in stage III nonsmall cell lung cancer (NSCLC) patients who were treated with chemoradiotherapy (CRT).

Materials and Methods

Systemic IDO1 activity was reflected by Kyn : Trp ratio. Plasma levels of Kyn and Trp in 113 stage III NSCLC patients were measured by high-performance liquid chromatography (HPLC) before the initiation of radiotherapy. Dynamic change of IDO1 activity was followed in 23 patients before, during, and after radiotherapy. We also used RNA sequencing (RNA-seq) data from the Cancer Genome Atlas Program (TCGA) database and performed gene set enrichment analysis (GSEA) to explore how IDO1 was involved in the development of RILT.

Results

9.7% (11/113) of the whole group developed G3+ (greater than or equal to Grade 3) RILT. Preradiation IDO1 activity was significantly higher in patients who developed G3 + RILT than in nonG3 + RILT patients. (P = 0.029, AUC = 0.70). Univariate and multivariate analyses showed that high IDO1 activity was independently associated with the risk of G3 + RILT (P = 0.034). A predictive model combining both IDO1 activity and FEV1 was established for severe RILT and displayed a moderate predictive value (AUC = 0.83, P < 0.001). The incidence of G3 + RILT was 2.6% (1/38) in patients with an IDO activity ≤0.069 and FEV1 > 59.4%, and 50.0% (6/12) in those with an IDO activity >0.069 and FEV1 ≤ 59.4%. Of 23 patients with dynamic tracking, the IDO1 activity of postradiation was significantly lower than midradiation (P = 0.021), though no significant differences among the three time points were observed (P = 0.070). Bioinformatic analysis using RNA-seq data from 1014 NSCLC patients revealed that IDO mainly functioned in the inflammatory response instead of the late fibrosis process in NSCLC patients.

Conclusion

High baseline IDO1 activity combined with unfavorable baseline FEV1 was predictive of severe RILT in unresectable stage III NSCLC patients. IDO1 might play a role in the acute inflammatory response. Finding effective interventions to alleviate RILT using IDO inhibitors is warranted in the future.

The mutual relationship between the host immune system and radiotherapy: stimulating the action of immune cells by irradiation

The effects of irradiation on tumor tissue and the host immune system are interrelated. The antitumor effect of irradiation is attenuated in the immunocompromised hosts. In addition, radiation alone positively and negatively influences the host immune system. The positive effects of radiation are summarized by the ability to help induce and enhance tumor-antigen-specific immune responses. The cancer-immunity cycle is a multistep framework that illustrates how the tumor-antigen-specific immune responses are induced and how the induced antigen-specific immune cells exert their functions in tumor tissues. Irradiation affects each step of this cancer-immunity cycle, primarily in a positive manner. In contrast, radiation also has negative effects on the immune system. The first is that irradiation has the possibility to kill irradiated effector immune cells. The second is that irradiation upregulates immunosuppressive molecules in the tumor microenvironment, whereas the third is that irradiation to the tumor condenses immunosuppressor cells in the tumor microenvironment. When used in conjunction with radiotherapy, immune checkpoint inhibitors can further leverage the positive effects of radiation on the immune system and compensate for the negative effects of irradiation, which supports the rationale for the combination of radiotherapy and immune checkpoint inhibitors. In this review, we summarize the preclinical evidence for the reciprocal effects of radiation exposure and the immune system, and up-front topics of the combination therapy of immune checkpoint inhibitors and radiotherapy.

Myeloid cell-targeted therapies for solid tumours

Myeloid cells are the most abundant immune components of the tumour microenvironment, where they have a variety of functions, ranging from immunosuppressive to immunostimulatory roles. The myeloid cell compartment comprises many different cell types, including monocytes, macrophages, dendritic cells and granulocytes, that are highly plastic and can differentiate into diverse phenotypes depending on cues received from their microenvironment. In the past few decades, we have gained a better appreciation of the complexity of myeloid cell subsets and how they are involved in tumour progression and resistance to cancer therapies, including immunotherapy. In this Review, we highlight key features of monocyte and macrophage biology that are being explored as potential targets for cancer therapies and what aspects of myeloid cells need a deeper understanding to identify rational combinatorial strategies to improve clinical outcomes of patients with cancer. We discuss therapies that aim to modulate the functional activities of myeloid cell populations, impacting their recruitment, survival and activity in the tumour microenvironment, acting at the level of cell surface receptors, signalling pathways, epigenetic machinery and metabolic regulators. We also describe advances in the development of genetically engineered myeloid cells for cancer therapy.

Unraveling the Complex Interconnection between Specific Inflammatory Signaling Pathways and Mechanisms Involved in HIV-Associated Colorectal Oncogenesis

The advancement of HIV treatment has led to increased life expectancy. However, people living with HIV (PLWH) are at a higher risk of developing colorectal cancers. Chronic inflammation has a key role in oncogenesis, affecting the initiation, promotion, transformation, and advancement of the disease. PLWH are prone to opportunistic infections that trigger inflammation. It has been documented that 15-20% of cancers are triggered by infections, and this percentage is expected to be increased in HIV co-infections. The incidence of parasitic infections such as helminths, with Ascariasis being the most common, is higher in HIV-infected individuals. Cancer cells and opportunistic infections drive a cascade of inflammatory responses which assist in evading immune surveillance, making them survive longer in the affected individuals. Their survival leads to a chronic inflammatory state which further increases the probability of oncogenesis. This review discusses the key inflammatory signaling pathways involved in disease pathogenesis in HIV-positive patients with colorectal cancers. The possibility of the involvement of co-infections in the advancement of the disease, along with highlights on signaling mechanisms that can potentially be utilized as therapeutic strategies to prevent oncogenesis or halt cancer progression, are addressed.

Enhancement of radiation therapy by indoleamine 2,3 dioxygenase 1 inhibition through multimodal mechanisms

BACKGROUND

Indoleamine 2,3-dioxygenase 1 (IDO1) is an enzyme that converts tryptophan to kynurenine. IDO1 expression is found not only in tumor cells but also in immune cells and is associated with tumor proliferation and immune responses. IDO1 inhibitors and radiation may cooperatively suppress tumor proliferation through the alterations in the Wnt/β-catenin pathway, cell cycle, and immune response. We investigated the antitumor effects of combination therapy of an IDO1 inhibitor, 1-methyl tryptophan (1-MT), and radiation on colorectal cancer.

METHODS

In vitro experiments were conducted using human and murine colon cancer cell lines (HCT116, HT-29, and Colon26). Cell growth inhibition was assessed using a MTS assay and Clonogenic assay. Cells were cultured for 48 h with or without 500 µM 1-MT after exposure to radiation (4 Gy). Cell cycle effects and modulation of Wnt/β-catenin pathway were evaluated using western blot analysis, flow cytometry, RT-PCR. Subcutaneous Colon26 tumors in BALB/c mice were treated by oral 1-MT (6 mg/mL) for 2 weeks and/or local radiation (10 Gy/10 fr). Bromodeoxyuridine (BrdU) incorporation in tumor cells and expression of differentiation markers of immune cells were evaluated using immunohistochemistry.

RESULTS

1-MT and a small interfering RNA against IDO1 suppressed proliferation of all cell lines, which was rescued by kynurenine. Clonogenic assay showed that administration of 1-MT improved radiosensitivity by suppressing the Wnt/β-catenin pathway activated by radiation and enhancing cell cycle arrest induced by radiation. Combination therapy showed a further reduction in tumor burden compared with monotherapies or untreated control, inducing the highest numbers of intratumoral CD3 + and CD8 + T cells and the lowest numbers of Foxp3 + and BrdU-positive tumor cells.

CONCLUSIONS

The combination of 1-MT and radiation suppressed colon cancer cells in vitro and in vivo via multiple mechanisms.

Novel insight into metabolic reprogrammming in cancer radioresistance: A promising therapeutic target in radiotherapy

Currently, cancer treatment mainly consists of surgery, radiotherapy, chemotherapy, immunotherapy, and molecular targeted therapy, of which radiotherapy is one of the major pillars. However, the occurrence of radioresistance largely limits its therapeutic effect. Metabolic reprogramming is an important hallmark in cancer progression and treatment resistance. In radiotherapy, DNA breakage is the major mechanism of cell damage, and in turn, cancer cells are prone to increase the metabolic flux of glucose, glutamine, serine, arginine, fatty acids etc., thus providing sufficient substrates and energy for DNA damage repair. Therefore, studying the linkage between metabolic reprogramming and cancer radioresistance may provide new ideas for improving the efficacy of tumor therapy. This review mainly focuses on the role of metabolic alterations, including glucose, amino acid, lipid, nucleotide and other ion metabolism, in radioresistance, and proposes possible therapeutic targets to improve the efficacy of cancer radiotherapy.

Triple blockade of Ido-1, PD-L1 and MEK as a potential therapeutic strategy in NSCLC

BACKGROUND

Despite the recent progress in the treatment and outcome of Non Small Cell Lung Cancer (NSCLC), immunotherapy has still significant limitations reporting a significant proportion of patients not benefiting from therapy, even in patients with high PD-L1 expression. We have previously demonstrated that the combined inhibition of MEK and PD-L1 in NSCLC patients derived three dimensional cultures exerted significant synergistic effect in terms of immune-dependent cancer cell death. However, subsequent experiments analyzing the expression of Indoleamine 2,3-dioxygenase-1 (Ido-1) gene expression demonstrated that Ido-1 resulted unaffected by the MEK inhibition and even increased after the combined inhibition of MEK and PD-L1 thus representing a potential escape mechanism to this combination.

METHODS

We analyzed transcriptomic profile of NSCLC lung adenocarcinoma cohort of TCGA (The Cancer Genome Atlas), stratifying tumors based on EMT (Epithelial mesenchymal Transition) score; in parallel, we investigated the activation of Ido-1 pathway and modulation of immune cytokines productions both in NSCLC cells lines, in peripheral blood mononuclear cells (PBMCs) and in ex-vivo NSCLC spheroids induced by triple inhibition with an anti-PD-L1 monoclonal antibody, the MEK inhibitor and the Ido-1 inhibitor.

RESULTS

In NSCLC lung adenocarcinoma patient cohort (from TCGA) Ido-1 gene expression was significantly higher in samples classified as mesenchymal according EMT score. Similarly, on a selected panel of NSCLC cell lines higher expression of MEK and Ido-1 related genes was detected in cells with mesenchymal phenotype according EMT score, thus suggesting a potential correlation of co-activation of these two pathways in the context of EMT, with cancer cells sustaining an immune-suppressive microenvironment. While exerting an antitumor activity, the dual blockade of MEK and PD-L1 enhances the secretion of pro-inflammatory cytokines (IFNγ, TNFα, IL-12 and IL-6) and, consequently, the expression of new immune checkpoints such as Ido-1. The triple inhibition with an anti-PD-L1 monoclonal antibody, the MEK inhibitor and the Ido-1 inhibitor demonstrated significant antiproliferative and proapoptotic activity on ex-vivo NSCLC samples; at the same time the triple combination kept increased the levels of pro-inflammatory cytokines produced by both PBMCs and tumor spheroids in order to sustain the immune response and simultaneously decreased the expression of other checkpoint (such as CTLA-4, Ido-1 and TIM-3) thus promoting an immune-reactive and inflamed micro-environment.

CONCLUSIONS

We show that Ido-1 activation is a possible escape mechanism to immune-mediated cell death induced by combination of PD-L1 and MEK inhibitors: also, we show that triple combination of anti-PD-L1, anti-MEK and anti-Ido-1 drugs may overcome this negative feedback and restore anti-tumor immune response in NSCLC patients' derived three dimensional cultures.

Cancer immunotherapy strategies that target the cGAS-STING pathway

Activation of the cGAS-STING pathway by cytoplasmic DNA induces the production of Type-1 interferons. Recent advances in research suggest that the cGAS-STING pathway is involved in different parts of the cancer-immunity cycle (CIC) to promote or suppress antitumor immune responses. Combination therapy of STING agonists has made certain progress in preclinical as well as clinical trials, but the selection of combination therapy regimens remains a challenge. In this review, we summarize the role of the cGAS-STING in all aspects of CIC, and focus on the combination immunotherapy strategies of STING agonists and current unsolved challenges.

Identification of Key Genes and FUNCTIONAL Pathway in Radioresistance of Non-Small Cell Lung Cancer

Purpose

For better understanding of radiotherapy resistance and its potential mechanism.

Methods

We established radioresistance cell lines of non-small cell lung cancer (NSCLC) followed by microarray analysis. 529 differentially expressed genes (DEGs) were then screened between radiation resistant cell lines compared with the sensitive cell lines. The biological functions and enrichment pathways of the above DEGs were identified using Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene ontology (GO) enrichment analyses. Gene Set Enrichment Analysis (GSEA) revealed that the radiation resistance group had the most gene sets enriched in altered immune response, such as TNF signaling pathway, when compared to the radiation sensitive group. Protein-protein interaction (PPI) network was carried out through the STRING database, and then five hub genes (CXCL10, IFIH1, DDX58, CXCL11, RSAD2) were screened by Cytoscape software. RT-PCR confirmed the expression of the above hub genes. ChIP-X Enrichment Analysis showed that STAT1 might be the transcription factor of the above hub genes. Considering that PD-L1 could be activated by STAT1 in a variety of tumors and ultimately lead to immune exhaustion, RT-PCR and Western blot verified the expression level of PD-L1.

Results

Five hub genes (CXCL10, IFIH1, DDX58, CXCL11, RSAD2) were screened and verified to be highly expressed in radioresistance group, STAT1 might be the transcription factor of the above hub genes. Our study found that the expression level of PD-L1 was increased after radiotherapy resistance.

Conclusion

Although immune system activation occurs followed by radiation resistance, we hypothesized that the upregulation of PD-L1 expression caused by STAT1 activation might be one of the mechanisms of radiotherapy resistance.

Evaluating the role of IDO1 macrophages in immunotherapy using scRNA-seq and bulk-seq in colorectal cancer

Background

Macrophage infiltration is crucial for colorectal cancer (CRC) immunotherapy. Detailed classification of macrophage subsets will facilitate the selection of patients suitable for immunotherapy. However, the classification of macrophages in CRC is not currently detailed.

Methods

In this study, we combined single-cell RNA sequencing (scRNA-seq) and bulk-seq to analyze patients with colorectal cancer. scRNA-seq data were used to study cell-cell communication and to differentiate immune-infiltrating cells and macrophage subsets. Bulk-seq data were used to further analyze immune infiltration, clinical features, tumor mutational burden, and expression of immune checkpoint molecules in patients with CRC having different macrophage subsets.

Results

Seven macrophage subpopulations were identified, among which indoleamine 2,3 dioxygenase 1 (IDO1) macrophages had the most significant difference in the degree of infiltration among normal, microsatellite-unstable, and microsatellite-stable populations. We then performed gene set variation analysis using 12 marker genes of IDO1 macrophages and divided the patients into two clusters: high-IDO1 macrophages (H-IDO1M) and low-IDO1 macrophages (L-IDO1M). H-IDO1M showed higher infiltration of immune cells, higher expression of immune checkpoints, and less advanced pathological stages than L-IDO1M (p < 0.05).

Conclusions

This study elucidated that IDO1-macrophage-based molecular subtypes can predict the response to immunotherapy in patients with CRC. The results provide new insights into tumor immunity and help in clinical decisions regarding designing effective immunotherapy for these patients.

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.

The expression and significance of efferocytosis and immune checkpoint related molecules in pancancer samples and the correlation of their expression with anticancer drug sensitivity

Background: The efferocytosis-related molecules have been considered to be correlated with the resistance to cancer chemotherapy. The aim of this study was to investigate the expression and significance of efferocytosis-related molecules in cancers and the correlation of their expression with anticancer drug sensitivity, and provide new potential targets and treatment options for cancers.

Methods: We investigated the differential expression of 15 efferocytosis-related molecules (Axl, Tyro3, MerTK, CX3CL1, Tim-4, BAI1, Stab2, Gas6, IDO1, Rac1, MFGE8, ICAM-1, CD47, CD31, and PD-L1) and other 12 common immune checkpoint-related molecules in tumor and normal tissues, the correlation between their expression and various clinicopathological features in 16 types of cancers using publicly available pancancer datasets in The Cancer Genome Atlas. We also analyzed the correlation of the expression of efferocytosis and immune checkpoint related molecules with 126 types of anticancer drugs sensitivity using drug-RNA-seq data.

Results: There is a panel of circulating molecules among the 27 molecules. Based on the results of differential expression and correlation with various clinicopathological features of efferocytosis-related molecules in cancers, we identified new potential therapeutic targets for anticancer therapy, such as Axl for kidney renal clear cell carcinoma, Tyro3 for liver hepatocellular carcinoma, and IDO1 for renal papillary cell carcinoma. Except for BAI1, CD31, and MerTK, the enhanced expressions of Axl, Tyro3, Gas6, MFGE8, Stab2, Tim-4, CX3CL1, IDO1, Rac1, and PD-L1 were associated with decreased sensitivity of the cancer cells to many anti-cancer drugs; however, for other common immune checkpoint-related molecules, only enhanced expressions of PD-1, CD28, CTLA4, and HVEM were associated with decreased sensitivity of the cancer cells to a few drugs.

Conclusion: The efferocytosis-related molecules were significantly associated with clinical outcomes in many types of cancers and played important roles in resistance to chemotherapy. Combination therapy targeting efferocytosis-related molecules and other immune checkpoint-related molecules is necessary to reduce resistance to chemotherapy.

Lymph node regression grading of locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy

Neoadjuvant chemoradiotherapy (nCRT) and total rectal mesenteric excision are the main standards of treatment for locally advanced rectal cancer (LARC). Lymph node regression grade (LRG) is an indicator of prognosis and response to preoperative nCRT based on postsurgical metastatic lymph node pathology. Common histopathological findings in metastatic lymph nodes after nCRT include necrosis, hemorrhage, nodular fibrosis, foamy histiocytes, cystic cell reactions, areas of hyalinosis, residual cancer cells, and pools of mucin. A number of LRG systems designed to classify the amount of lymph node regression after nCRT is mainly concerned with the relationship between residual cancer cells and regressive fibrosis and with estimating the number of lymph nodes existing with residual cancer cells. LRG offers significant prognostic information, and in most cases, LRG after nCRT correlates with patient outcomes. In this review, we describe the systematic classification of LRG after nCRT, patient prognosis, the correlation with tumor regression grade, and the typical histopathological findings of lymph nodes. This work may serve as a reference to help predict the clinical complete response and determine lymph node regression in patients based on preservation strategies, allowing for the formulation of more accurate treatment strategies for LARC patients, which has important clinical significance and scientific value.

Novel LncRNA ZFHX4-AS1 as a Potential Prognostic Biomarker That Affects the Immune Microenvironment in Ovarian Cancer

Background

Ovarian cancer (OvCa) is a malignant disease of the female reproductive system with a high mortality rate. LncRNA has been confirmed to play a crucial role in the development and progression of various cancer types. Novel lncRNA ZFHX4-AS1 has been reported in several cancers, albeit its functional mechanisms in OvCa remain unclear.

Methods

With reference to the public databases and based on integrating bioinformatics analyses, we explored the expression of ZFHX4-AS1 and its roles in the prognosis of OvCa. We employed the Kaplan-Meier curves to investigate the outcome of patients with different ZFHX4-AS1 expressions. Furthermore, its biological function and the related hallmark pathways were assessed through Gene Ontology (GO) annotation, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses, and Gene-set enrichment analysis (GSEA). We explored the correlation between lncRNA ZFHX4-AS1 and tumor-infiltrating immune cells through CIBERSORT. The immune checkpoints associated with lncRNA ZFHX4-AS1 and its related genes were investigated. The effect of lncRNA ZFHX4-AS1 on proliferation, invasion and migration of OvCa cells was verified through Cell Counting Kit (CCK)-8, colony formation, wound healing and transwell assays.

Results

The expression of lncRNA ZFHX4-AS1 was upregulated in OvCa relative to that in normal tissues. Increased lncRNA ZFHX4-AS1 expression was associated with poor overall survival and progression-free survival in OvCa. The GO and KEGG pathway analyses revealed the role of lncRNA ZFHX4-AS1 in cell metabolism, protein synthesis, cell proliferation, and cell cycle. GSEA indicated the hallmark gene sets that were significantly enriched in the high and low expression groups. The CIBERSORT database revealed M2 macrophages, memory B-cells, naïve B cells, and activated NK cells were affected by lncRNA ZFHX4-AS1 expression (all P < 0.05). The expression of lncRNA ZFHX4-AS1 and its related differential genes MRPS11, NSA2, and MRPL13 were significantly correlated with the immune checkpoints. Knockdown of lncRNA ZFHX4-AS1 could inhibit the proliferation, invasion and migration of OvCa cells.

Conclusions

The results suggested that lncRNA ZFHX4-AS1 is a novel prognostic biomarker associated with cell proliferation, metabolism, infiltration, and distribution of tumor-infiltrating immune cells in OvCa, indicating that lncRNA ZFHX4-AS1 can be used as a potential therapeutic target for OvCa in the future.

Anti-inflammatory and anti-apoptotic effects of Shaoyao decoction on X-ray radiation-induced enteritis of C57BL/6 mice

ETHNOPHARMACOLOGICAL RELEVANCE

As a typical heat-clearing prescription, Shaoyao decoction (SYD) has a robust function of clearing viscera heat for the treatment of several intestinal discomfort symptoms. Clinical evidence indicated that it had the potential to cure radiation enteritis. However, its underlying mechanisms remain unclear.

AIM OF THE STUDY

The present study was designed to probe the protective effects and the involved mechanisms of SYD on X-ray radiation-induced enteritis of C57BL/6 mice.

MATERIALS AND METHODS

X-ray irradiation were used to establish the radiation enteritis model. Forty-eight male C57BL/6 mice (20 ± 2 g) were randomly divided into six groups: the control group, model group, dexamethasone group (DEX, 0.12 mg/kg) and SYD groups (0.12, 0.24 and 0.36 g/mL), respectively. All mice (except the control group) were intragastrically administrated for a continuous 7 days. H&E and Masson staining were employed to evaluate the morphological and collagen fibers changes of the colon. ELISA was performed to assess the levels of MDA, SOD, COX, LPS, IL-6, IL-1β and TNF-α in serum. Moreover, TUNEL fluorescence, western blot and qRT-PCR were used to detect the levels of apoptosis-related proteins and genes of Dclk-1, ATM, MRE-11, Bcl-2, Bax, Caspase-3, and Cyto-c. Furthermore, immunofluorescent staining was applied to detect the protein levels of p53 and Claudin-1 in colon.

RESULTS

Treatment with SYD decreased the exfoliated and necrotic epithelial cells and prevent the proliferate from damaged fibrous tissue in the crypt layer of mucos. The levels of serum peroxidation and pro-inflammatory cytokines (MDA, COX, LPS, IL-6, IL-1β and TNF-α) were obviously inhibited, while SOD sharply increased in serum after administration. Moreover, SYD can significantly ameliorate the apoptosis of colon cells, evidenced by the reduced positive expression of TUNEL staining. Meanwhile, the results of qRT-PCR and western blot demonstrated that SYD can dramatically stimulate the expression of genes and proteins Dclk-1, ATM and MRE-11, thus promoting the expression of mitochondrial pro-apoptotic proteins Bax, Caspase-3 and Cyto-c, while increasing the level of anti-apoptotic protein Bcl-2. Furthermore, immunofluorescence revealed that SYD can notably decreased the protein level of p53 while reverse the reduction of Claudin-1.

CONCLUSIONS

These results indicated that radiation enteritis in C57BL/6 mice can be ameliorated by treatment with SYD. The potential protection mechanisms may be involved in ameliorating tissue fibrosis by decreasing inflammatory and apoptotic events.

The Role of Indoleamine 2, 3-Dioxygenase 1 in Regulating Tumor Microenvironment

Indoleamine 2, 3-dioxygenase 1 (IDO1) is a rate-limiting enzyme that metabolizes an essential amino acid tryptophan (Trp) into kynurenine (Kyn), and it promotes the occurrence of immunosuppressive effects by regulating the consumption of Trp and the accumulation of Kyn in the tumor microenvironment (TME). Recent studies have shown that the main cellular components of TME interact with each other through this pathway to promote the formation of tumor immunosuppressive microenvironment. Here, we review the role of the immunosuppression mechanisms mediated by the IDO1 pathway in tumor growth. We discuss obstacles encountered in using IDO1 as a new tumor immunotherapy target, as well as the current clinical research progress.

Non-Coding RNAs Implicated in the Tumor Microenvironment of Colorectal Cancer: Roles, Mechanisms and Clinical Study

Colorectal cancer (CRC) is one of the most common malignant tumors. The morbidity and mortality rates have been increasing all over the world. It is critical to elucidate the mechanism of CRC occurrence and development. However, tumor microenvironment (TME) includes immune cells, fibroblasts, endothelial cells, cytokines, chemokines and other components that affect the progression of CRC and patients' prognosis. Non-coding RNAs (ncRNAs) including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), circular RNAs (circRNAs) without protein-coding ability have been shown to engage in tumor microenvironment-mediated angiogenesis and metastasis. Therefore, clarifying the mechanism of ncRNAs regulating the microenvironment is very important to develop the therapeutic target of CRC and improve the survival time of patients. This review focuses on the role and mechanism of ncRNAs in the CRC microenvironment and puts forward possible clinical treatment strategies.

Impacts and mechanisms of metabolic reprogramming of tumor microenvironment for immunotherapy in gastric cancer

Metabolic disorders and abnormal immune function changes occur in tumor tissues and cells to varying degrees. There is increasing evidence that reprogrammed energy metabolism contributes to the development of tumor suppressive immune microenvironment and influences the course of gastric cancer (GC). Current studies have found that tumor microenvironment (TME) also has important clinicopathological significance in predicting prognosis and therapeutic efficacy. Novel approaches targeting TME therapy, such as immune checkpoint blockade (ICB), metabolic inhibitors and key enzymes of immune metabolism, have been involved in the treatment of GC. However, the interaction between GC cells metabolism and immune metabolism and how to make better use of these immunotherapy methods in the complex TME in GC are still being explored. Here, we discuss how metabolic reprogramming of GC cells and immune cells involved in GC immune responses modulate anti-tumor immune responses, as well as the effects of gastrointestinal flora in TME and GC. It is also proposed how to enhance anti-tumor immune response by understanding the targeted metabolism of these metabolic reprogramming to provide direction for the treatment and prognosis of GC.

Molecular Mechanisms of Tumor Immunomodulation in the Microenvironment of Colorectal Cancer

Colorectal cancer remains one of the most important health challenges in our society. The development of cancer immunotherapies has fostered the need to better understand the anti-tumor immune mechanisms at play in the tumor microenvironment and the strategies by which the tumor escapes them. In this review, we provide an overview of the molecular interactions that regulate tumor inflammation. We particularly discuss immunomodulatory cell-cell interactions, cell-soluble factor interactions, cell-extracellular matrix interactions and cell-microbiome interactions. While doing so, we highlight relevant examples of tumor immunomodulation in colorectal cancer.

Antiviral Responses in Cancer: Boosting Antitumor Immunity Through Activation of Interferon Pathway in the Tumor Microenvironment

In recent years, it became apparent that cancers either associated with viral infections or aberrantly expressing endogenous retroviral elements (EREs) are more immunogenic, exhibiting an intense intra-tumor immune cell infiltration characterized by a robust cytolytic apparatus. On the other hand, epigenetic regulation of EREs is crucial to maintain steady-state conditions and cell homeostasis. In line with this, epigenetic disruptions within steady-state cells can lead to cancer development and trigger the release of EREs into the cytoplasmic compartment. As such, detection of viral molecules by intracellular innate immune sensors leads to the production of type I and type III interferons that act to induce an antiviral state, thus restraining viral replication. This knowledge has recently gained momentum due to the possibility of triggering intratumoral activation of interferon responses, which could be used as an adjuvant to elicit strong anti-tumor immune responses that ultimately lead to a cascade of cytokine production. Accordingly, several therapeutic approaches are currently being tested using this rationale to improve responses to cancer immunotherapies. In this review, we discuss the immune mechanisms operating in viral infections, show evidence that exogenous viruses and endogenous retroviruses in cancer may enhance tumor immunogenicity, dissect the epigenetic control of EREs, and point to interferon pathway activation in the tumor milieu as a promising molecular predictive marker and immunotherapy target. Finally, we briefly discuss current strategies to modulate these responses within tumor tissues, including the clinical use of innate immune receptor agonists and DNA demethylating agents.

Indoleamine 2,3-dioxygenase 1 (IDO1) inhibitors and PROTAC-based degraders for cancer therapy

Indoleamine 2,3-dioxygenase 1 (IDO1), a known immunosuppressive enzyme that catalyzes the rate-limiting step in the oxidation of tryptophan (Trp) to kynurenine (Kyn), has received increasing attention as an attractive immunotherapeutic target for cancer therapy. Up to now, eleven small-molecule IDO1 inhibitors have entered clinical trials for the treatment of cancers. In addition, proteolysis targeting chimera (PROTAC) based degraders also provide prospects for cancer therapy. Herein we present a comprehensive overview of the medicinal chemistry strategies and potential therapeutic applications of IDO1 inhibitors in nonclinical trials and IDO1-PROTAC degraders.

Multiomics Differences in Lung Squamous Cell Carcinoma Patients with High Radiosensitivity Index Compared with Those with Low Radiosensitivity Index

Objectives

Radiosensitivity Index (RSI) can predict intrinsic radiotherapy sensitivity. We analyzed multiomics characteristics in lung squamous cell carcinoma between high and low RSI groups, which may help understand the underlying molecular mechanism of radiosensitivity and guide optional treatment for patients in the future.

Methods

The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) data were used to download clinical data, mRNA, microRNA, and lncRNA expression. Differential analyses, including mRNA, miRNA, lncRNA, and G.O. and KEGG, and GSVA analyses, were performed with R. Gene set enrichment analysis was done by GSEA. miRNA-differentially expressed gene network and ceRNA network were analyzed and graphed by the Cytoscape software.

Results

In TCGA data, 542 patients were obtained, including 171 in the low RSI group (LRSI) and 371 in the high RSI group (HRSI). In RNAseq, 558 significantly differentially expressed genes (DEGs) were obtained. KRT6A was the most significantly upregulated gene and IDO1 was the most significantly downregulated gene. In miRNAseq, miR-1269a was the most significantly upregulated. In lncRNAseq, LINC01871 was the most upregulated. A 66-pair interaction between differentially expressed genes and miRNAs and an 11-pair interaction between differential lncRNAs and miRNAs consisted of a ceRNA network, of which miR-184 and miR-490-3p were located in the center. In the GEO data, there were 40 DEGs. A total of 17 genes were founded in both databases, such as ADAM23, AHNAK2, BST2, COL11A1, CXCL13, FBN2, IFI27, IFI44L, MAGEA6, and PTGR1. GSVA analysis revealed 31 significant pathways. GSEA found 87 gene sets enriched in HRSI and 91 gene sets in LRSI. G.O. and KEGG of RNA expression levels revealed that these genes were most enriched in T cell activation and cytokine-cytokine receptor interaction.

Conclusions

Patients with lung squamous cell carcinoma have different multiomics characteristics between two groups. These differences may have an essential significance with radiotherapy effect.

Genotype of Immunologically Hot or Cold Tumors Determines the Antitumor Immune Response and Efficacy by Fully Virulent Retargeted oHSV

We report on the efficacy of the non-attenuated HER2-retargeted oHSV named R-337 against the immunologically hot CT26-HER2 tumor, and an insight into the basis of the immune protection. Preliminarily, we conducted an RNA immune profiling and immune cell content characterization of CT26-HER2 tumor in comparison to the immunologically cold LLC1-HER2 tumor. CT26-HER2 tumor was implanted into HER2-transgenic BALB/c mice. Hallmarks of R-337 effects were the protection from primary tumor, long-term adaptive vaccination directed to both HER2 and CT26-wt cell neoantigens. The latter effect differentiated R-337 from OncoVEXGM-CSF. As to the basis of the immune protection, R-337 orchestrated several changes to the tumor immune profile, which cumulatively reversed the immunosuppression typical of this tumor (graphical abstract). Thus, Ido1 (inhibitor of T cell anticancer immunity) levels and T regulatory cell infiltration were decreased; Cd40 and Cd27 co-immunostimulatory markers were increased; the IFNγ cascade was activated. Of note was the dampening of IFN-I response, which we attribute to the fact that R-337 is fully equipped with genes that contrast the host innate response. The IFN-I shut-down likely favored viral replication and the expression of the mIL-12 payload, which, in turn, boosted the antitumor response. The results call for a characterization of tumor immune markers to employ oncolytic herpesviruses more precisely.

Moving Beyond the Standard of Care: Accelerate Testing of Radiation-Drug Combinations

Radiation therapy is a major treatment modality used in > 60% of cancer patients as definitive local treatment for inoperable locoregionally confined tumors and as palliative therapy. Although cytotoxic chemotherapy enhances the effectiveness of treatment, the benefit over radiation therapy alone is modest. There is a need to enhance the effectiveness of local tumor control over what sequentially or concurrently administered cytotoxic chemotherapy provides. Although many biological pathways are known to enhance the effectiveness of radiation therapy, there is currently a paucity of drugs approved for use in combination. Several clinical trials have tested the effectiveness of combining targeted agents or immunotherapies with radiation therapy, but the results of these trials have been negative, likely stemming from the relative lack of preclinical evidence using appropriate experimental standardization or model systems. Accelerating the identification of agents tested in an appropriate clinical context and experimental systems or models would greatly enhance the potential to bring forward early testing of drugs that would not only be safe but also more effective. This article provides an overview of the opportunities and challenges of developing therapeutics to combine with radiation therapy, and some guidance toward preclinical and early clinical testing to improve the chance that advanced phase testing of drug-radiation combinations would be successful in the long term.

Targeted Immunotherapies in Gastrointestinal Cancer: From Molecular Mechanisms to Implications

Gastrointestinal cancer is a leading cause of cancer-related mortality and remains a major challenge for cancer treatment. Despite the combined administration of modern surgical techniques and chemoradiotherapy (CRT), the overall 5-year survival rate of gastrointestinal cancer patients in advanced stage disease is less than 15%, due to rapid disease progression, metastasis, and CRT resistance. A better understanding of the mechanisms underlying cancer progression and optimized treatment strategies for gastrointestinal cancer are urgently needed. With increasing evidence highlighting the protective role of immune responses in cancer initiation and progression, immunotherapy has become a hot research topic in the integrative management of gastrointestinal cancer. Here, an overview of the molecular understanding of colorectal cancer, esophageal cancer and gastric cancer is provided. Subsequently, recently developed immunotherapy strategies, including immune checkpoint inhibitors, chimeric antigen receptor T cell therapies, tumor vaccines and therapies targeting other immune cells, have been described. Finally, the underlying mechanisms, fundamental research and clinical trials of each agent are discussed. Overall, this review summarizes recent advances and future directions for immunotherapy for patients with gastrointestinal malignancies.

Regulation of lnc-TLCD2-1 on Radiation Sensitivity of Colorectal Cancer and Comprehensive Analysis of Its Mechanism

As is well known that colorectal cancer is the third most common cancer in the world, and radiation treatment plays a vital role in colorectal cancer therapy, but radiation resistance is a significant problem in the treatment of colorectal cancer. As an important member of the non-coding RNA family, long non-coding RNAs (lncRNAs) have been found that it plays a role in the occurrence and progression of colorectal cancer in recent years. However, little is known about the effect of lncRNA on colorectal cancer sensitivity to radiotherapy. We found that lnc-TLCD2-1 was significantly differentially expressed in radiation-tolerant CCL244 cell lines and radiation-sensitive HCT116 cell lines, suggesting that lnc-TLCD2-1 may regulate the radiosensitivity of colorectal cancer, and the relevant underlying mechanism was investigated. Cell clone formation assay, flow cytometry, and cell counting kit 8 (CCK8) were used to detect radiation sensitivity, apoptosis, and proliferation of colorectal cancer cells, respectively; Quantitative real-time PCR and western blot were used to detect the expression of genes; the direct interaction between lnc-TLCD2-1 and hsa-miR-193a-5p was verified by dual luciferase reporter assays; GEPIA, Starbase, TIMER and DAVID were used to complete expression of lnc-TLCD2-1, miR-193a-5p,YY1 and NF-кB-P65 in colorectal cancer, correlation, immune cell infiltration, GO and KEGG enrichment analysis. Clinical prognostic analysis data were obtained from GSE17536 dataset. After radiotherapy for HCT116, the expression of lnc-TLCD2-1 was increased, and the expression of hsa-miR-193a-5p was significantly decreased, while that of CCL244 was the opposite, and the change range of lnc-TLCD2-1 was relatively small. HCT116 with overexpression of lnc-TLCD2-1 after radiation treatment, the number of cell colonies significantly increased, and cell apoptosis decreased compared with the negative control group. The cell colonies and apoptosis of CCL244 with disturbed expression of lnc-TLCD2-1 were opposite to those of HCT116. Lnc-TLCD2-1 can regulate the expression of YY1/NF-кB-P65 by targeting miR-193a-5p. Lnc-TLCD2-1 can promote the proliferation of colorectal cancer. High expression of lnc-TLCD2-1 independently predicted a shorter survival. Lnc-TLCD2-1 is associated with radiation resistance and short survival in colorectal cancer patients. In addition, Lnc-TLCD2-1 can promote the proliferation of colorectal cancer. Our study provides a scientific basis for targeting lnc-TLCD2-1 in colorectal cancer radiation resistance interventions and selection of prognostic biomarker.

Local Destruction of Tumors and Systemic Immune Effects

Current immune-based therapies signify a major advancement in cancer therapy; yet, they are not effective in the majority of patients. Physically based local destruction techniques have been shown to induce immunologic effects and are increasingly used in order to improve the outcome of immunotherapies. The various local destruction methods have different modes of action and there is considerable variation between the different techniques with respect to the ability and frequency to create a systemic anti-tumor immunologic effect. Since the abscopal effect is considered to be the best indicator of a relevant immunologic effect, the present review focused on the tissue changes associated with this effect in order to find determinants for a strong immunologic response, both when local destruction is used alone and combined with immunotherapy. In addition to the T cell-inflammation that was induced by all methods, the analysis indicated that it was important for an optimal outcome that the released antigens were not destroyed, tumor cell death was necrotic and tumor tissue perfusion was at least partially preserved allowing for antigen presentation, immune cell trafficking and reduction of hypoxia. Local treatment with controlled low level hyperthermia met these requisites and was especially prone to result in abscopal immune activity on its own.

Direct and indirect immune effects of CMP-001, a virus-like particle containing a TLR9 agonist

Background

CMP-001, also known as vidutolimod, is a virus-like particle containing a TLR9 agonist that is showing promise in early clinical trials. Our group previously demonstrated that the immunostimulatory effects of CMP-001 are dependent on an anti-Qβ antibody response which results in opsonization of CMP-001 and uptake by plasmacytoid dendritic cells (pDCs) that then produce interferon (IFN)-α. IFN-α then leads to an antitumor T-cell response that is responsible for the in vivo efficacy of CMP-001. Here, we explore mechanisms by which the initial effects of CMP-001 on pDCs activate other cells that can contribute to development of an antitumor T-cell response.

Methods

Uptake of CMP-001 by various peripheral blood mononuclear cell (PBMC) populations and response to anti-Qβ-coated CMP-001 were evaluated by flow cytometry and single-cell RNA sequencing. Purified monocytes were treated with anti-Qβ-coated CMP-001 or recombinant IFN-α to evaluate direct and secondary effects of anti-Qβ-coated CMP-001 on monocytes.

Results

Monocytes had the highest per cell uptake of anti-Qβ-coated CMP-001 with lower levels of uptake by pDCs and other cell types. Treatment of PBMCs with anti-Qβ-coated CMP-001 induced upregulation of IFN-responsive genes including CXCL10, PDL1, and indoleamine-2,3-dioxygenase (IDO) expression by monocytes. Most of the impact of anti-Qβ-coated CMP-001 on monocytes was indirect and mediated by IFN-α, but uptake of anti-Qβ-coated CMP-001 altered the monocytic response to IFN-α and resulted in enhanced expression of PDL1, IDO, and CD80 and suppressed expression of CXCL10. These changes included an enhanced ability to induce autologous CD4 T-cell proliferation.

Conclusions

Anti-Qβ-coated CMP-001 induces IFN-α production by pDCs which has secondary effects on a variety of cells including monocytes. Uptake of anti-Qβ-coated CMP-001 by monocytes alters their response to IFN-α, resulting in enhanced expression of PDL1, IDO and CD80 and suppressed expression of CXCL10. Despite aspects of an immunosuppressive phenotype, these monocytes demonstrated increased ability to augment autologous CD4 T-cell proliferation. These findings shed light on the complexity of the mechanism of action of anti-Qβ-coated CMP-001 and provide insight into pathways that may be targeted to further enhance the efficacy of this novel approach to immunotherapy.

Immunity, immunotherapy, and rectal cancer: A clinical and translational science review

Rectal cancer remains a challenging disease to treat. Therapy for locally advanced rectal cancer (LARC), the most frequent presentation, has evolved to include a multimodal approach of radiation, chemotherapy, and surgery. While this approach improves local disease control, the distant recurrence rate is nearly 30% and treatment-related morbidity is substantial, thus underscoring the need for new therapeutic approaches with better efficacy and lower side effects. Immunotherapy could potentially fill this need, but its promise is not yet realized in rectal cancer. In this translational science review, we address what is known about how cytotoxic therapies shape rectal cancer immunity and potentially prime the tumor microenvironment for response to immune checkpoint inhibitors and other immunotherapies. We also address the role of current immunotherapies in colorectal cancer and highlight where novel immunotherapy approaches are currently being evaluated in LARC. Finally, we address important future directions in LARC immunotherapy including the need to define optimal therapeutic sequencing, predictive biomarkers, strategies to limit treatment-related side effects and the potential of gut microbiome manipulation to improve outcomes. In summary, this review provides a framework to guide future research and inform immunotherapy trial design so as to advance rectal cancer care.