Differences in Tumor Microenvironment Dictate T Helper Lineage Polarization and Response to Immune Checkpoint Therapy

Immune microenvironment of cancer bone metastasis

Bone is a common and frequent site of metastasis in cancer patients, leading to a significant reduction in quality of life and increased mortality. Bone marrow, the primary site of hematopoiesis, also serves as both a primary and secondary lymphoid organ. It harbors and supports a diverse array of immune cells, thereby creating a distinct immune microenvironment. These immune cells engage in a range of activities, including anti-tumor, pro-tumor, or a combination of both, which influence the development and progression of bone metastases. Rapid advances in cancer immunotherapy have underscored its potential to eradicate bone metastases. However, clinical outcomes have not yet met expectations. To improve the efficacy of immunotherapy, it is crucial to gain a comprehensive and in-depth understanding of the immune microenvironment within bone metastases. This review provides an overview of the current understanding of the role of different immune cells, their anti-tumor and pro-tumor activities, and their overall contribution to bone metastasis.

DYRK1A-TGF-β signaling axis determines sensitivity to OXPHOS inhibition in hepatocellular carcinoma

Intervening in mitochondrial oxidative phosphorylation (OXPHOS) has emerged as a potential therapeutic strategy for certain types of cancers. Employing kinome-based CRISPR screen, we find that knockout of dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) synergizes with OXPHOS inhibitor IACS-010759 in liver cancer cells. Targeting DYRK1A combined with OXPHOS inhibitors activates TGF-β signaling, which is crucial for OXPHOS-inhibition-triggered cell death. Mechanistically, upregulation of glutamine transporter solute carrier family 1 member 5 (SLC1A5) transcription compensates for the increased glutamine requirement upon OXPHOS inhibition. DYRK1A directly phosphorylates SMAD3 Thr132, thereby suppressing the negative impact of TGF-β signaling on transcription of SLC1A5, leading to intrinsic resistance of liver cancer cells to OXPHOS inhibition. Moreover, we demonstrate the therapeutic efficacy of IACS-010759 in combination with DYRK1A inhibition in multiple liver cancer models, including xenografts, patient-derived xenografts, and spontaneous tumor model. Our study elucidates how the DYRK1A-TGF-β signaling axis controls the response of tumor cells to OXPHOS inhibition and provides valuable insights into targeting OXPHOS for liver cancer therapy.

Ultrasound-triggered drug-loaded nanobubbles for enhanced T cell recruitment in cancer chemoimmunotherapy

Chemotherapy combined with immunotherapy is a highly promising approach for treating tumors. However, chemotherapeutic drugs often fail to accumulate effectively at the tumor site after systemic administration and they lack sufficient immunogenicity to activate adaptive immunity, making an effective T-cell immune response within the tumor microenvironment difficult to achieve. Here, this work developed drug-loaded nanobubbles (DTX-R837@NBs) that encapsulate the chemotherapy drug docetaxel and the immune adjuvant R837 via a thin-film hydration method. Ultrasound-targeted nanobubble destruction promoted drug accumulation within tumor tissues and damaged tumor cells through the cavitation effect, inducing immunogenic cell death and releasing damage-associated molecular patterns to augment dendritic cell maturation. Notably, DTX-R837@NBs exhibited excellent contrast-enhanced ultrasound imaging capabilities, enabling the seamless integration of diagnosis and treatment. In combination with immune checkpoint blockade targeting programmed cell death protein 1 (PD-1), the generated immunological responses attacked residual tumor cells and ameliorated the immunosuppressive tumor microenvironment, inhibiting distant tumor growth and metastasis. Moreover, this strategy exhibited robust immune memory effects, effectively protecting the host and preventing tumor recurrence upon rechallenge. Overall, ultrasound-mediated DTX-R837@NBs combined with anti-PD-1 immune checkpoint blockade therapy exhibits robust antitumor efficiency, represent a promising strategy for overcoming immunotherapy resistance in cold tumors, and warrant further investigation for clinical translation.

Tumor-intrinsic regulators of the immune-cold microenvironment of prostate cancer

Prostate cancer (PC) is a notoriously immune-cold tumor in that it often lacks substantial infiltration by antitumor immune cells, and in advanced diseases such as neuroendocrine PC, it could be devoid of immune cells. A majority of PC patients thus have, unfortunately, been unable to benefit from recent advances in immunotherapies. What causes this immunosuppressive microenvironment around PC? In this review, we discuss various genetic and epigenetic regulators intrinsic to prostate tumor cells that could have profound effects on the tumor microenvironment, thus contributing to this immune-cold status. It will be essential to target the cancer cells themselves in order to change the tumor microenvironment to harness existing and developing immunotherapies that had great success in other tumors.

Elevated HSPB1 Expression Is Associated with a Poor Prognosis in Glioblastoma Multiforme Patients

BACKGROUND

 Glioblastoma multiforme (GBM) is a highly aggressive form of brain cancer. This study investigated the clinical predictive value of heat shock protein β1 (HSPB1) in patients with GBM.

METHODS

 A correlation was established between HSPB1 expression and GBM progression using data from The Cancer Genome Atlas (TCGA) dataset, Chinese Glioma Genome Atlas dataset, Gene Expression Omnibus dataset, and Human Protein Atlas database. A survival analysis was conducted and an HSPB1-based nomogram was constructed to evaluate the prognostic value of HSPB1 in patients with GBM.

RESULTS

 Based on TCGA data mining, we discovered that HSPB1 was significantly elevated in patients with GBM and may reflect their response to immunotherapy. In survival analysis, it appeared to have a predictive role in the prognosis of patients with GBM. Five signaling pathways were significantly enriched in the high HSPB1 expression phenotype according to the gene set enrichment analysis. In addition, a significant association was found between HSPB1 expression and immune checkpoints, tumor immune infiltration, tumor immune microenvironment, and immune cell markers in glioma. Overall, our results suggest that HSPB1 may regulate the function of immune cells, serve as a new immunotherapy target, and predict the response to immunotherapy in patients with GBM.

CONCLUSION

 HSPB1 appears to serve as a potential predictor of the clinical prognosis and response to immunotherapy in patients with GBM. It may be possible to identify patients who are likely to benefit from immunotherapy by assessing the expression level of HSPB1.

Understanding and overcoming resistance to immunotherapy in genitourinary cancers

The introduction of novel immunotherapies has significantly transformed the treatment landscape of genitourinary (GU) cancers, even becoming the standard of care in some settings. One such type of immunotherapy, immune checkpoint inhibitors (ICIs) like nivolumab, ipilimumab, pembrolizumab, and atezolizumab play a pivotal role by disturbing signaling pathways that limit the immune system's ability to fight tumor cells. Despite the profound impact of these treatments, not all tumors are responsive. Recent research efforts have been focused on understanding how cancer cells manage to evade the immune response and identifying the possible mechanisms behind resistance to immunotherapy. In response, ICIs are being combined with other treatments to reduce resistance and attack cancer cells through multiple cellular pathways. Additionally, novel, targeted strategies are currently being investigated to develop innovative methods of overcoming resistance and treatment failure. This article presents a comprehensive overview of the mechanisms of immunotherapy resistance in GU cancers as currently described in the literature. It explores studies that have identified genetic markers, cytokines, and proteins that may predict resistance or response to immunotherapy. Additionally, we review current efforts to overcome this resistance, which include combination ICIs and sequential therapies, novel insights into the host immune profile, and new targeted therapies. Various approaches that combine immunotherapy with chemotherapy, targeted therapy, vaccines, and radiation have been studied in an effort to more effectively overcome resistance to immunotherapy. While each of these combination therapies has shown some efficacy in clinical trials, a deeper understanding of the immune system's role underscores the potential of novel targeted therapies as a particularly promising area of current research. Currently, several targeted agents are in development, along with the identification of key immune mediators involved in immunotherapy resistance. Further research is necessary to identify predictors of response.

The CCL5/CCR5/SHP2 axis sustains Stat1 phosphorylation and activates NF-κB signaling promoting M1 macrophage polarization and exacerbating chronic prostatic inflammation

BACKGROUND AND OBJECTIVE

Chronic prostatitis (CP) is a condition markered by persistent prostate inflammation, yet the specific cytokines driving its progression remain largely undefined. This study aims to identify key cytokines involved in CP and investigate their role in driving inflammatory responses through mechanistic and therapeutic exploration.

METHODS

A 48-cytokine panel test was conducted to compare the plasma cytokine profiles between participants with CP-like symptoms (CP-LS) and healthy controls. Experimental autoimmune prostatitis (EAP) models were used for functional validation, with further mechanistic studies performed through in vivo and in vitro assays. Pharmacological inhibition was applied using maraviroc, and pathway inhibitors to assess therapeutic potential.

RESULTS

Our analysis identified CCL5 as one of the most prominently elevated cytokines in CP-LS patients. Further validation in the EAP model mice confirmed elevated CCL5 levels, highlighting its role in driving prostatic inflammation. Mechanistic studies revealed that CCL5 interacts with the CCR5 receptor, promoting M1 macrophage polarization and activating key inflammatory signaling pathways, including Stat1 and NF-κB, as indicated by increased phosphorylation of Stat1 and p65. In vitro, CCL5 combined with LPS stimulation amplified these effects, further promoting M1 polarization. CCL5 also sustained Stat1 activation by inhibiting its dephosphorylation through reduced interaction with SHP2, leading to prolonged inflammatory signaling. Single-cell transcriptomics confirmed high CCR5 expression in macrophages, correlating with inflammatory pathways. Pharmacological inhibition of CCR5, or its downstream signaling, significantly reduced macrophage-driven inflammation both in vivo and in vitro.

CONCLUSION

These findings establish the CCL5/CCR5 axis as a critical driver of persistant prostatic inflammation and present it as a potential therapeutic target for CP.

Evolution of myeloid-mediated immunotherapy resistance in prostate cancer

Patients with advanced metastatic castration-resistant prostate cancer (mCRPC) are refractory to immune checkpoint inhibitors (ICIs)1,2, partly because there are immunosuppressive myeloid cells in tumours3,4. However, the heterogeneity of myeloid cells has made them difficult to target, making blockade of the colony stimulating factor-1 receptor (CSF1R) clinically ineffective. Here we use single-cell profiling on patient biopsies across the disease continuum and find that a distinct population of tumour-associated macrophages with elevated levels of SPP1 transcripts (SPP1hi-TAMs) becomes enriched with the progression of prostate cancer to mCRPC. In syngeneic mouse modelling, an analogous macrophage population suppresses CD8+ T cell activity in vitro and promotes ICI resistance in vivo. Furthermore, Spp1hi-TAMs are not responsive to anti-CSF1R antibody treatment. Pathway analysis identifies adenosine signalling as a potential mechanism for SPP1hi-TAM-mediated immunotherapeutic resistance. Indeed, pharmacological inhibition of adenosine A2A receptors (A2ARs) significantly reverses Spp1hi-TAM-mediated immunosuppression in CD8+ T cells in vitro and enhances CRPC responsiveness to programmed cell death protein 1 (PD-1) blockade in vivo. Consistent with preclinical results, inhibition of A2ARs using ciforadenant in combination with programmed death 1 ligand 1 (PD-L1) blockade using atezolizumab induces clinical responses in patients with mCRPC. Moreover, inhibiting A2ARs results in a significant decrease in SPP1hi-TAM abundance in CRPC, indicating that this pathway is involved in both induction and downstream immunosuppression. Collectively, these findings establish SPP1hi-TAMs as key mediators of ICI resistance in mCRPC through adenosine signalling, emphasizing their importance as both a therapeutic target and a potential biomarker for predicting treatment efficacy.

How the bone microenvironment shapes the pre-metastatic niche and metastasis

The bone is a frequent metastatic site, with changes in the mineralized bone and the bone marrow milieu that can also prime other sites for metastasis by educating progenitor cells to support metastatic spread. Stromal and immune populations cooperatively maintain the organizationally complex bone niches and are dysregulated in the presence of a distant primary tumor and metastatic disease. Interrogating the bone niches that facilitate metastatic spread using innovative technologies holds the potential to aid in preventing metastasis in and mediated by the bone. Here, we review recent advances in bone niche biology and its adaptations in the context of cancer.

Delineating the nexus between gut-intratumoral microbiome and osteo-immune system in bone metastases

Emerging insights in osteoimmunology have enabled researchers to explore in depth the role of immune modulation in regulating bone health. Bone is one of the common sites of metastasis notably in case of breast cancer, prostate cancer and several other cancer types. High calcium ion concentration and presence of several factors within the mineralized bone matrix including TGF-β, BMP etc., aid in tumor growth and proliferation. Accumulating evidence has substantiated the role of the gut-microbiota (GM) in tumorigenesis, further providing a strong impetus for the growing "immune-cancer-gut microbiota" relationship. Recent advancements in research further highlight the importance of the intra-tumor microbiota in conjunction with GM in cancer metastasis. Intratumoral microbiota owing to their ability to cause genetic instability, mutations, and epigenetic modifications within the tumor microenvironment, has been recognized to affect cancer cell physiology. The host microbiota and immune system crosstalk shapes the innate and adaptive arms of the immune system, which is the key player in cancer progression. In this review, we aim to decipher the role of microorganisms mediating bone metastasis by shedding light on the immuno-onco-microbiome (IOM) axis. We discussed the feasible cancer therapeutic interventions based on the modulation of the microbiome-immune cell axis which includes prebiotics, probiotics, and postbiotics. Here, we leverage the conceptual framework based on the published articles on microbiota-based therapies to target bone metastases. Understanding this complicated nexus will provide insights into fundamental factors governing bone metastases which will subsequently help in managing this malignancy with better efficacy.

Osteoimmunology in bone malignancies: a symphony with evil

Bone marrow is pivotal for normal hematopoiesis and immune responses, yet it is often compromised by malignancies. The bone microenvironment (BME), composed of bone and immune cells, maintains skeletal integrity and blood production. The emergence of primary or metastatic tumors in the skeletal system results in severe complications and contributes significantly to cancer-related mortality. These tumors set off a series of interactions among cancer, bone, and immune cells, and disrupt the BME locally or distantly. However, the drivers, participants, and underlying molecules of these interactions are not fully understood. This review explores the crosstalk between bone metabolism and immune responses, synthesizing current knowledge on the intersection of cancer and osteoimmune biology. It outlines how bone marrow immune cells can either facilitate or hinder tumor progression by interacting with bone cells and pinpoints the molecules responsible for immunosuppression within bone tumors. Moreover, it discusses how primary tumors remotely alter the BME, leading to systemic immune suppression in cancer patients. This knowledge provides critical rationales for emerging immunotherapies in the treatment of bone-related tumors. Taken together, by summarizing the intricate relationship between tumor cells and the BME, this review aims to deepen the understanding of the diversity, complexity, and dynamics at play during bone tumor progression. Ultimately, it highlights the potential of targeting bone-tumor interactions to correct aberrant immune functions, thereby inhibiting tumor growth and metastasis.

Integrated analysis of single-cell RNA-seq and bulk RNA-seq revealed key genes for bone metastasis and chemoresistance in prostate cancer

BACKGROUND

Prostate cancer (PCa) is a serious malignancy. The main causes of PCa aggravation and death are unexplained resistance to chemotherapy and bone metastases.

OBJECTIVE

This study aimed to investigate the molecular mechanisms associated with the dynamic processes of progression, bone metastasis, and chemoresistance in PCa.

METHODS

Through comprehensive analysis of single-cell RNA sequencing (scRNA-seq) data, Gene Expression Omnibus (GEO) tumor progression and metastasis-related genes were identified. These genes were subjected to lasso regression modeling using the Cancer Genome Atlas (TCGA) database. Tartrate-resistant acid phosphatase (TRAP) staining and real-time quantitative PCR (RT-qPCR) were used to evaluate osteoclast differentiation. CellMiner was used to confirm the effect of LDHA on chemoresistance. Finally, the relationship between LDHA and chemoresistance was verified using doxorubicin-resistant PCa cell lines.

RESULTS

7928 genes were identified as genes related to tumor progression and metastasis. Of these, 7 genes were found to be associated with PCa prognosis. The scRNA-seq and TCGA data showed that the expression of LDHA was higher in tumors and associated with poor prognosis of PCa. In addition, upregulation of LDHA in PCa cells induces osteoclast differentiation. Additionally, high LDHA expression was associated with resistance to Epirubicin, Elliptinium acetate, and doxorubicin. Cellular experiments demonstrated that LDHA knockdown inhibited doxorubicin resistance in PCa cells.

CONCLUSIONS

LDHA may play a potential contributory role in PCa initiation and development, bone metastasis, and chemoresistance. LDHA is a key target for the treatment of PCa.

Macrophage diversity in cancer dissemination and metastasis

Invasion and metastasis are hallmarks of cancer. In addition to the well-recognized hematogenous and lymphatic pathways of metastasis, cancer cell dissemination can occur via the transcoelomic and perineural routes, which are typical of ovarian and pancreatic cancer, respectively. Macrophages are a universal major component of the tumor microenvironment and, in established tumors, promote growth and dissemination to secondary sites. Here, we review the role of tumor-associated macrophages (TAMs) in cancer cell dissemination and metastasis, emphasizing the diversity of myeloid cells in different tissue contexts (lungs, liver, brain, bone, peritoneal cavity, nerves). The generally used models of lung metastasis fail to capture the diversity of pathways and tissue microenvironments. A better understanding of TAM diversity in different tissue contexts may pave the way for tailored diagnostic and therapeutic approaches.

The effect of radiotherapy, chemotherapy, and immunotherapy on fusion rate in spinal surgery using osteobiologics for patients with metastatic spinal disease: a systematic review

OBJECTIVE

To evaluate the impact that adjuvant therapies like radiotherapy, chemotherapy, and immunotherapy have on osteobiologic properties and bony regeneration in patients with metastatic spine disease (MSD) undergoing spinal fusion surgery.

METHODS

PubMed and ClinicalTrials.gov searches were performed. MSD patients undergoing fusion surgery with an osteobiologic and radiotherapy, chemotherapy and/or immunotherapy were included. Demographics, primary tumor, surgery, adjuvant treatments, osteobiologic type, fusion rates with scoring criteria, hardware failure, reoperation rates, follow-up, and survival were extracted. 1487 studies were screened, 20 included.

RESULTS

585 patients (464 with MSD) had fusion rates ranging from 17.9 to 100%. In the setting of radiotherapy, fusion rates of 10 studies using autologous bone graft (autograft), 5 studies using allogenic bone graft (allograft), 5 studies using combination autograft/allograft, 4 studies using biomaterial scaffolds (BMS), 3 studies using demineralized bone matrices (DBM), and 1 study using growth factors (GF), were 50-100%, 17.9-100%, 57.8-100%, 52.9-100%, 20-100%, and 100%, respectively. A higher incidence of fusion in patients with autograft or allograft receiving stereotactic body radiotherapy (SBRT) at lower biologically effective doses (BED) and at least 1-month postoperatively was noted. Chemotherapy had no impact on fusion. No studies evaluated the impact of immunotherapy on fusion.

CONCLUSIONS

SBRT at lower doses given greater than 1-month postoperatively may enhance bony fusion in patients receiving autograft, allograft, or autograft/allograft. Chemotherapy may delay bony fusion without affecting overall fusion rates. Preclinical studies suggest immunotherapy may prevent osteolysis and promote osteogenesis, but no studies have yet evaluated the clinical impact of these findings on spinal fusion. Further research is needed on osteobiologics in bony regeneration in the MSD population.

ITGA5 is associated with prognosis marker and immunosuppression in head and neck squamous cell carcinoma

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is a major tumor that seriously threatens the health of the head and neck or mucosal system. It is manifested as a malignant phenotype of high metastasis and invasion caused by squamous cell transformation in the tissue area. Therefore, it is necessary to search for a biomarker that can systematically correlate and reflect the prognosis of HNSCC based on the characteristics of head and neck tumors.

METHODS

Based on TCGA-HNSCC data, R software was used to analyze gene expression, correlation, Venn diagram, immune invasive and immunosuppressive phenotypes respectively. The intrinsic effect of ITGA5 on the malignant phenotype of HNSCC cells was verified by cell experiments. Immunohistochemical images from The Human Protein Atlas (THPA) database display the differences in the expression of related proteins in HNSCC tissues. Based on functional enrichment and correlation analysis, the prognostic value of ITGA5 for HNSCC was explored, and the expression level of ITGA5 may affect the chemotherapy of targeting the PI3K-AKT.

RESULTS

In this study, the target gene ITGA5 may be identified as a valuable prognostic marker for HNSCC. The results of enrichment analysis showed that ITGA5 was mainly involved in the dynamic process of extracellular matrix, which may affect the migration or metastasis of tumor cells. Meanwhile, ITGA5 may be closely related to the infiltration of M2 macrophages, and its secretory phenotypes TGFB1, PDGFA and PDGFB may affect the immunosuppressive phenotypes of tumor cells, which reflects the systemic influence of ITGA5 in HNSCC. In addition, the expression levels of ITGA5 were negatively correlated with the efficacy of targeting PI3K-AKT chemotherapy.

CONCLUSION

ITGA5 can be used as a potential marker to systematically associate with prognosis of HNSCC, which may be associated with HNSCC malignant phenotype, immunosuppression and chemotherapy resistance.

Advances in and prospects of immunotherapy for prostate cancer

Immunotherapy has shown promising therapeutic effects in hematological malignancies and certain solid tumors and has emerged as a critical and highly potential treatment modality for cancer. However, prostate cancer falls under the category of immune-resistant cold tumors, for which immunotherapy exhibits limited efficacy in patients with solid tumors. Thus, it is important to gain a deeper understanding of the tumor microenvironment in prostate cancer to facilitate immune system activation and overcome immune suppression to advance immunotherapy for prostate cancer. In this review, we discuss the immunosuppressive microenvironment of prostate cancer, which is characterized by the presence of few tumor-infiltrating lymphocytes, abundant immunosuppressive cells, low immunogenicity, and a noninflammatory phenotype, which significantly influences the efficacy of immunotherapy for prostate cancer. Immunotherapy is mainly achieved by activating the host immune system and overcoming immunosuppression. In this regard, we summarize the therapeutic advances in immune checkpoint blockade, immunogenic cell death, reversal of the immunosuppressive tumor microenvironment, tumor vaccines, immune adjuvants, chimeric antigen receptor T-cell therapy, and overcoming penetration barriers in prostate cancer, with the aim of providing novel research insights and approaches to enhance the effectiveness of immunotherapy for prostate cancer.

Structural analysis of Salvia miltiorrhiza polysaccharide and its regulatory functions on T cells subsets in tumor-bearing mice combined with thymopentin

Salvia miltiorrhiza ethanol-extracted polysaccharide (SMEP) and thymopentin (TP5) have been proved with strong immunomodulatory activity, and T cells subsets play pivotal roles in the inhibition of solid tumors growth. In the present study, the structure of SMEP was further identified via methylation and nuclear magnetic resonance spectra, and the immunomodulatory activity in combination with TP5 was investigated via evaluating T cell subsets spatial distributions in tumor-bearing mice, finally the cellular status of solid tumor cells was analyzed. The results revealed that SMEP was a neutral heteropolysaccharide using (1 → 4)-α-D-Glcp and (2 → 1)-β-D-Fruf as the main chain, along with branched chains of (1 → 6)-α-D-Galp. The SMEP+TP5 treatments could effectively promote the differentiation and improve the specific recognition capacity of CD4+ T cells in tumor-bearing mice, thereby activate tumor-infiltrating CD8+ T cells to exert cytotoxic effects, finally promoting the tumor cells apoptosis via blocking cell cycle at G0/G1 phase, which might be relevant with suppression of Wnt/β-catenin signaling pathway. These findings highlighted the potential of SMEP as an immunoadjuvant for patients bearing immune-deficiency related diseases, and provided data support for the functional researches of T cell subsets in tumor immunity.

Unraveling Th subsets: insights into their role in immune checkpoint inhibitor therapy

T helper (Th) cell subsets play pivotal roles in regulating immune responses within the tumor microenvironment, influencing both tumor progression and anti-tumor immunity. Among these subsets, Th1 cells promote cytotoxic responses through the production of IFN-γ, while Th2 cells and regulatory T cells (Tregs) exert immunosuppressive effects that support tumor growth. Th9 and Th17 cells have context-dependent roles, contributing to both pro-inflammatory and regulatory processes in tumor immunity. Tumor antigen-specific T cells within the tumor microenvironment often exhibit a dysfunctional phenotype due to increased expression of inhibitory receptors such as CTLA-4 and PD-1, leading to reduced antitumor activity. Monoclonal antibodies that block these inhibitory signals-collectively known as immune checkpoint inhibitors (ICIs)-can reactivate these T cells, enhancing their ability to target and destroy cancer cells. Recent advancements have highlighted the critical role of T helper subsets in modulating responses to ICIs, with their interactions remaining a focus of ongoing research. Both positive and negative effects of ICIs have been reported in relation to Th cell subsets, with some effects depending on the type of tumor microenvironment. This review summarizes the crucial roles of different T helper cell subsets in tumor immunity and their complex relationship with immune checkpoint inhibitor therapy.

Survival outcomes in patients with de novo metastatic Merkel cell carcinoma according to site of metastases

Introduction

Merkel cell carcinoma (MCC) is a rare and aggressive neuroendocrine malignancy of the skin with a predilection for metastases. This study investigates the clinical outcomes in patients presenting with de novo Stage IV MCC according to the metastatic site(s) at presentation.

Materials and methods

Patients who presented with one or more sites of distant metastatic MCC at initial diagnosis between 2009 and 2023 were identified. The presence or absence of one or more metastases in each organ was categorized for each patient at the time of diagnosis. Overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan-Meier method. Competing risk analysis was used to estimate the cumulative occurrence risk of MCC-specific death. Fisher's exact test was used for response rate analysis. Results were considered statically significant if p < 0.05.

Results

Thirty-four patients presented with de novo distant metastatic MCC. There was no association between the number of metastatic sites at diagnosis and OS (p= 0.58), PFS (p=0.79), or response rates (p=0.53). However, the presence of bone metastases was associated with significantly shorter OS (8.2 versus 25.2 months, HR: 2.4, 95% CI 1.01-5.7, p= 0.04). MCC-specific death in patients with lymph node metastases was significantly lower than in patients without (HR: 0.28, 95% CI: 0.09-0.87, p= 0.013). The presence of bone metastases tended to associate with an increased risk of MCC-specific death, although not statistically significant. The location of metastases was not associated with the response rate to first-line treatment. There was no significant association between site of metastases and PFS.

Conclusion

In this cohort of patients with de novo metastatic MCC, the presence of bone metastases, but not the number of organs involved, was associated with significantly worse OS. The presence of lymph node metastases was associated with lower MCC-specific death. Further research is warranted in larger cohorts to investigate the impact of the location of metastases on clinical outcomes.

Prostate cancer-induced endothelial-cell-to-osteoblast transition drives immunosuppression in the bone-tumor microenvironment through Wnt pathway-induced M2 macrophage polarization

Immune checkpoint therapy has limited efficacy for patients with bone-metastatic castration-resistant prostate cancer (bmCRPC). To improve immunotherapy for bmCRPC, we aimed to identify the mechanism of bmCRPC-induced changes in the immune microenvironment. Among bmCRPC patients, higher levels of a 32-gene M2-like macrophage signature in bone metastasis samples correlated with shorter overall survival. Immunohistochemistry showed that CD206-positive (CD206+) macrophages were enriched in bmCRPC bone biopsy specimens compared with primary tumors or lymph node metastases. In preclinical osteogenic prostate cancer (Pca) xenograft models, CD206+ macrophages were recruited to areas with tumor-induced bone. RNA sequencing (RNAseq) analysis showed higher expression of an M2-like gene signature, with activated canonical and noncanonical Wnt pathways, in tumor-associated macrophages isolated from osteogenic tumors (bone-TAMs) than in TAMs isolated from nonosteogenic tumors (ctrl-TAMs). Mechanistic studies showed that endothelial cells (ECs) that had undergone EC-to-osteoblast (EC-to-OSB) transition, the precursors of tumor-induced OSBs, produced paracrine factors, including Wnts, CXCL14, and lysyl oxidase, which induced M2 polarization and recruited M2-like TAMs to the bone-tumor microenvironment (bone-TME). Bone-TAMs suppressed CD8+ T cells' proliferation and cytolytic activity, and these effects were partially reversed by treating bone-TAMs with Wnt inhibitors. Genetic or pharmacological inhibition of Pca-induced EC-to-OSB transition reduced the levels of M2-like macrophages in osteogenic tumors. Our study demonstrates that Pca-induced EC-to-OSB transition drives immunosuppression in the bone-TME, suggesting that therapies that reduce Pca-induced bone formation may improve immunotherapeutic outcomes for bmCRPC.

Development and Validation of a Machine Learning Model for Bone Metastasis in Prostate Cancer: Based on Inflammatory and Nutritional Indicators

OBJECTIVE

To establish a predictive model for prostate cancer bone metastasis utilizing multiple machine learning algorithms.

METHODS

Retrospective analysis of the clinical data of prostate cancer initially diagnosed in the Department of Urology of Gansu Provincial People's Hospital from June 2017 to June 2022. Logistic regression (LR) and least absolute shrinkage and selection operator (LASSO) are used to jointly screen the model features. The filtered features are incorporated into algorithms including LR, random forest (RF), extreme gradient boosting (XGBoost), naive Bayes (NB), k-nearest neighbor (KNN), and decision tree (DT), to develop prostate cancer bone metastasis models.

RESULTS

A total of 404 patients were finally screened. Gleason score, T stage, N stage, PSA, and ALP were used as features for modeling. The average AUC of the 5-fold cross-validation for each machine learning model in the training set is as follows: LR (AUC=0.9054), RF (AUC=0.9032), NB (AUC=0.8961), KNN (AUC=0.8704), DT (AUC=0.8526), XGBoost (AUC=0.8066). The AUC of each machine learning model in the test set is KNN (AUC=0.9390, 95%CI: 0.8760-1), RF (AUC=0.9290, 95%CI: 0.8718-0.9861), NB (AUC=0.9268, 95%CI: 0.8615-0.9920), LR (AUC=0.9212, 95%CI: 0.8506-0.9917), XGBoost (AUC=0.8292, 95%CI: 0.7442-0.9141), DT (AUC=0.8057, 95%CI: 0.7100-0.9014). A comprehensive evaluation showed that LR performed well in interpretability and clinical applications.

CONCLUSION

A bone metastasis model of prostate cancer was established, and it was observed that indicators such as inflammation and nutrition had a weak correlation with bone metastasis.

Elucidating the Intricate Roles of Gut and Breast Microbiomes in Breast Cancer Metastasis to the Bone

BACKGROUND

Breast cancer is the most predominant and heterogeneous cancer in women. Moreover, breast cancer has a high prevalence to metastasize to distant organs, such as the brain, lungs, and bones. Patients with breast cancer metastasis to the bones have poor overall and relapse-free survival. Moreover, treatment using chemotherapy and immunotherapy is ineffective in preventing or reducing cancer metastasis.

RECENT FINDINGS

Microorganisms residing in the gut and breast, termed as the resident microbiome, have a significant influence on the formation and progression of breast cancer. Recent studies have identified some microorganisms that induce breast cancer metastasis to the bone. These organisms utilize multiple mechanisms, including induction of epithelial-mesenchymal transition, steroid hormone metabolism, immune modification, bone remodeling, and secretion of microbial products that alter tumor microenvironment, and enhance propensity of breast cancer cells to metastasize. However, their involvement makes these microorganisms suitable as novel therapeutic targets. Thus, studies are underway to prevent and reduce breast cancer metastasis to distant organs, including the bone, using chemotherapeutic or immunotherapeutic drugs, along with probiotics, antibiotics or fecal microbiota transplantation.

CONCLUSIONS

The present review describes association of gut and breast microbiomes with bone metastases. We have elaborated on the mechanisms utilized by breast and gut microbiomes that induce breast cancer metastasis, especially to the bone. The review also highlights the current treatment options that may target both the microbiomes for preventing or reducing breast cancer metastases. Finally, we have specified the necessity of maintaining a diverse gut microbiome to prevent dysbiosis, which otherwise may induce breast carcinogenesis and metastasis especially to the bone. The review may facilitate more detailed investigations of the causal associations between these microbiomes and bone metastases. Moreover, the potential treatment options described in the review may promote discussions and research on the modes to improve survival of patients with breast cancer by targeting the gut and breast microbiomes.

Synthetic lethal CRISPR screen identifies a cancer cell-intrinsic role of PD-L1 in regulation of vulnerability to ferroptosis

Despite the success of programmed cell death 1 (PD-1)/programmed death ligand 1 (PD-L1) inhibition in tumor therapy, many patients do not benefit. This failure may be attributed to the intrinsic functions of PD-L1. We perform a genome-wide CRISPR synthetic lethality screen to systematically explore the intrinsic functions of PD-L1 in head and neck squamous cell carcinoma (HNSCC) cells, identifying ferroptosis-related genes as essential for the viability of PD-L1-deficient cells. Genetic and pharmacological induction of ferroptosis accelerates cell death in PD-L1 knockout cells, which are also more susceptible to immunogenic ferroptosis. Mechanistically, nuclear PD-L1 transcriptionally activates SOD2 to maintain redox homeostasis. Lower reactive oxygen species (ROS) and ferroptosis are observed in patients with HNSCC who have higher PD-L1 expression. Our study illustrates that PD-L1 confers ferroptosis resistance in HNSCC cells by activating the SOD2-mediated antioxidant pathway, suggesting that targeting the intrinsic functions of PD-L1 could enhance therapeutic efficacy.

Pan-cancer mapping of single CD8+ T cell profiles reveals a TCF1:CXCR6 axis regulating CD28 co-stimulation and anti-tumor immunity

CD8+ T cells must persist and function in diverse tumor microenvironments to exert their effects. Thus, understanding common underlying expression programs could better inform the next generation of immunotherapies. We apply a generalizable matrix factorization algorithm that recovers both shared and context-specific expression programs from diverse datasets to a single-cell RNA sequencing (scRNA-seq) compendium of 33,161 CD8+ T cells from 132 patients with seven human cancers. Our meta-single-cell analyses uncover a pan-cancer T cell dysfunction program that predicts clinical non-response to checkpoint blockade in melanoma and highlights CXCR6 as a pan-cancer marker of chronically activated T cells. Cxcr6 is trans-activated by AP-1 and repressed by TCF1. Using mouse models, we show that Cxcr6 deletion in CD8+ T cells increases apoptosis of PD1+TIM3+ cells, dampens CD28 signaling, and compromises tumor growth control. Our study uncovers a TCF1:CXCR6 axis that counterbalances PD1-mediated suppression of CD8+ cell responses and is essential for effective anti-tumor immunity.

Loss of tumor suppressors promotes inflammatory tumor microenvironment and enhances LAG3+T cell mediated immune suppression

Low response rate, treatment relapse, and resistance remain key challenges for cancer treatment with immune checkpoint blockade (ICB). Here we report that loss of specific tumor suppressors (TS) induces an inflammatory response and promotes an immune suppressive tumor microenvironment. Importantly, low expression of these TSs is associated with a higher expression of immune checkpoint inhibitory mediators. Here we identify, by using in vivo CRISPR/Cas9 based loss-of-function screening, that NF1, TSC1, and TGF-β RII as TSs regulating immune composition. Loss of each of these three TSs leads to alterations in chromatin accessibility and enhances IL6-JAK3-STAT3/6 inflammatory pathways. This results in an immune suppressive landscape, characterized by increased numbers of LAG3+ CD8 and CD4 T cells. ICB targeting LAG3 and PD-L1 simultaneously inhibits metastatic progression in preclinical triple negative breast cancer (TNBC) mouse models of NF1-, TSC1- or TGF-β RII- deficient tumors. Our study thus reveals a role of TSs in regulating metastasis via non-cell-autonomous modulation of the immune compartment and provides proof-of-principle for ICB targeting LAG3 for patients with NF1-, TSC1- or TGF-β RII-inactivated cancers.

A Modular Trial of Androgen Signaling Inhibitor Combinations Testing a Risk-Adapted Strategy in Patients with Metastatic Castration-Resistant Prostate Cancer

PURPOSE

To determine the efficacy and safety of risk-adapted combinations of androgen signaling inhibitors and inform disease classifiers for metastatic castration-resistant prostate cancers.

PATIENTS AND METHODS

In a modular, randomized phase II trial, 192 men were treated with 8 weeks of abiraterone acetate, prednisone, and apalutamide (AAPA; module 1) and then allocated to modules 2 or 3 based on satisfactory (≥50% PSA decline from baseline and <5 circulating tumor cell/7.5 mL) versus unsatisfactory status. Men in the former were randomly assigned to continue AAPA alone (module 2A) or with ipilimumab (module 2B). Men in the latter group had carboplatin + cabazitaxel added to AAPA (module 3). Optional baseline biopsies were subjected to correlative studies.

RESULTS

Median overall survival (from allocation) was 46.4 [95% confidence interval (CI), 39.2-68.2], 41.4 (95% CI, 33.3-49.9), and 18.7 (95% CI, 14.3-26.3) months in modules 2A (n = 64), 2B (n = 64), and 3 (n = 59), respectively. Toxicities were within expectations. Of 192 eligible patients, 154 (80.2%) underwent pretreatment metastatic biopsies. The aggressive-variant prostate cancer molecular profile (defects in ≥2 of p53, RB1, and PTEN) was associated with unsatisfactory status. Exploratory analyses suggested that secreted phosphoprotein 1-positive and insulin-like growth factor-binding protein 2-positive macrophages, druggable myeloid cell markers, and germline pathogenic mutations were enriched in the unsatisfactory group.

CONCLUSIONS

Adding ipilimumab to AAPA did not improve outcomes in men with androgen-responsive metastatic castration-resistant prostate cancer. Despite the addition of carboplatin + cabazitaxel, men in the unsatisfactory group had shortened survivals. Adaptive designs can enrich for biologically and clinically relevant disease subgroups to contribute to the development of marker-informed, risk-adapted therapy strategies in men with prostate cancer.

Effectiveness of immune checkpoint inhibitor therapy on bone metastases in non-small-cell lung cancer

Background

Bone metastases (BoMs) are prevalent in patients with metastatic non-small-cell lung cancer (NSCLC) however, there are limited data detailing how BoMs respond to immune checkpoint inhibitors (ICIs). The purpose of this study was to compare the imaging response to ICIs of BoMs against visceral metastases and to evaluate the effect of BoMs on survival.

Materials and methods

A retrospective, multicentre cohort study was conducted in patients with NSCLC treated with nivolumab or pembrolizumab in Alberta, Canada from 2015 to 2020. The primary endpoint was the real-world organ specific progression free survival (osPFS) of bone versus visceral metastases. Visceral metastases were categorized as adrenal, brain, liver, lung, lymph node, or other intra-abdominal lesions. The secondary outcome was overall survival (OS) amongst patients with and without BoMs.

Results

A total of 573 patients were included of which all patients had visceral metastases and 243 patients (42.4%) had BoMs. High PD-L1 expression was identified in 268 patients (46.8%). No significant difference in osPFS was observed between bone, liver, and intra-abdominal metastases (p=0.20 and p=0.76, respectively), with all showing shorter osPFS than other disease sites. There was no difference in the osPFS of extra-thoracic sites of disease in patients with high PD-L1 expression. There was significant discordance between visceral disease response and bone disease response to ICI (p=0.047). The presence of BoMs was an independent poor prognostic factor for OS (HR 1.26, 95%CI: 1.05-1.53, p=0.01).

Conclusion

Metastatic bone, liver, and intra-abdominal lesions demonstrated inferior clinical responses to ICI relative to other sites of disease. Additionally, the presence of bone and liver metastases were independent poor prognostic factors for overall survival. This real-world data suggests that BoMs respond poorly to ICI and may require treatment adjuncts for disease control.

A pan-cancer analysis of EphA family gene expression and its association with prognosis, tumor microenvironment, and therapeutic targets

Background

Erythropoietin-producing human hepatocellular (Eph) receptors stand out as the most expansive group of receptor tyrosine kinases (RTKs). Accumulating evidence suggests that within this expansive family, the EphA subset is implicated in driving cancer cell progression, proliferation, invasion, and metastasis, making it a promising target for anticancer treatment. Nonetheless, the extent of EphA family involvement across diverse cancers, along with its intricate interplay with immunity and the tumor microenvironment (TME), remains to be fully illuminated.

Methods

The relationships between EphA gene expression and patient survival, immunological subtypes, and TME characteristics were investigated based on The Cancer Genome Atlas (TCGA) database. The analyses employed various R packages.

Results

A significant difference in expression was identified for most EphA genes when comparing cancer tissues and non-cancer tissues. These genes independently functioned as prognostic factors spanning multiple cancer types. Moreover, a significant correlation surfaced between EphA gene expression and immune subtypes, except for EphA5, EphA6, and EphA8. EphA3 independently influenced the prognosis of papillary renal cell carcinoma (KIRP). This particular gene exhibited links with immune infiltration subtypes and clinicopathologic parameters, holding promise as a valuable biomarker for predicting prognosis and responsiveness to immunotherapy in patients with KIRP.

Conclusion

By meticulously scrutinizing the panorama of EphA genes in a spectrum of cancers, this study supplemented a complete map of the effect of EphA family in Pan-cancer and suggested that EphA family may be a potential target for cancer therapy.

The Macrophage migration inhibitory factor is a vital player in Pan-Cancer by functioning as a M0 Macrophage biomarker

BACKGROUND

The role of the macrophage migration inhibitory factor (MIF) has recently attracted considerable attention in cancer research; nonetheless, the insights provided by current investigations remain constrained. Our main objective was to investigate its role and the latent mechanisms within the pan-cancer realm.

METHODS

We used comprehensive pan-cancer bulk sequencing data and online network tools to investigate the association between MIF expression and patient prognosis, genomic instability, cancer cell stemness, DNA damage repair, and immune infiltration. Furthermore, we validated the relationship between MIF expression and M0 macrophages using single-cell datasets, the SpatialDB database, and fluorescence staining. Additionally, we assessed the therapeutic response using the ROC plotter tool.

RESULTS

We observed the upregulation of MIF expression across numerous cancer types. Notably, elevated MIF levels were associated with a decline in genomic stability. We found a significant correlation between increased MIF expression and increased expression of mismatch repair genes, stemness features, and homologous recombination genes across diverse malignancies. Subsequently, through an analysis using ESTIMATE and cytokine results, we revealed the involvement of MIF in immune suppression. Then, we validated MIF as a hallmark of the M0 macrophages involved in tumor immunity. Our study suggests an association with other immune-inhibitory cellular populations and restraint of CD8 + T cells. In addition, we conducted a comparative analysis of MIF expression before and after treatment in three distinct sets of therapy responders and non-responders. Intriguingly, we identified notable disparities in MIF expression patterns in bladder urothelial carcinoma and ovarian cancer following particular therapeutic interventions.

CONCLUSION

Comprehensive pan-cancer analysis revealed notable enrichment of MIF within M0 macrophages, exerting a profound influence on tumor-associated immunosuppression and the intricate machinery of DNA repair.

Bi-specific T-cell engagers (BiTEs) in prostate cancer and strategies to enhance development: hope for a BiTE-r future

Metastatic castrate resistant prostate cancer (mCRPC) continues to have poor survival rates due to limited treatment options. Bi-specific T cell engagers (BiTEs) are a promising class of novel immunotherapies with demonstrated success in haematological malignancies and melanoma. BiTEs developed for tumour associated antigens in prostate cancer have entered clinical testing. These trials have been hampered by high rates of treatment related adverse events, minimal or transient anti-tumour efficacy and generation of high titres of anti-drug antibodies. This paper aims to analyse the challenges faced by the different BiTE therapy constructs and the mCRPC tumour microenvironment that result in therapeutic resistance and identify possible strategies to overcome these issues.

Ketogenic Diet Alters the Epigenetic and Immune Landscape of Prostate Cancer to Overcome Resistance to Immune Checkpoint Blockade Therapy

Resistance to immune checkpoint blockade (ICB) therapy represents a formidable clinical challenge limiting the efficacy of immunotherapy. In particular, prostate cancer poses a challenge for ICB therapy due to its immunosuppressive features. A ketogenic diet (KD) has been reported to enhance response to ICB therapy in some other cancer models. However, adverse effects associated with continuous KD were also observed, demanding better mechanistic understanding and optimized regimens for using KD as an immunotherapy sensitizer. In this study, we established a series of ICB-resistant prostate cancer cell lines and developed a highly effective strategy of combining anti-PD1 and anti-CTLA4 antibodies with histone deacetylase inhibitor (HDACi) vorinostat, a cyclic KD (CKD), or dietary supplementation of the ketone body β-hydroxybutyrate (BHB), which is an endogenous HDACi. CKD and BHB supplementation each delayed prostate cancer tumor growth as monotherapy, and both BHB and adaptive immunity were required for the antitumor activity of CKD. Single-cell transcriptomic and proteomic profiling revealed that HDACi and ketogenesis enhanced ICB efficacy through both cancer cell-intrinsic mechanisms, including upregulation of MHC class I molecules, and -extrinsic mechanisms, such as CD8+ T-cell chemoattraction, M1/M2 macrophage rebalancing, monocyte differentiation toward antigen-presenting cells, and diminished neutrophil infiltration. Overall, these findings illuminate a potential clinical path of using HDACi and optimized KD regimens to enhance ICB therapy for prostate cancer.

SIGNIFICANCE

Optimized cyclic ketogenic diet and 1,3-butanediol supplementation regimens enhance the efficacy of immune checkpoint blockade in prostate cancer through epigenetic and immune modulations, providing dietary interventions to sensitize tumors to immunotherapy.

Molecular landscape of prostate cancer bone metastasis

Prostate cancer (PC) has a high propensity to develop bone metastases, causing severe pain and pathological fractures that profoundly impact a patients' normal functions. Current clinical intervention is mainly palliative focused on pain management, and tumor progression is refractory to standard therapeutic regimens. This limited treatment efficacy is at least partially due to a lack of comprehensive understanding of the molecular landscape of the disease pathology, along with the intensive overlapping of physiological and pathological molecular signaling. The niche is overwhelmed with diverse cell types with inter- and intra-heterogeneity, along with growth factor-enriched cells that are supportive of invading cell proliferation, providing an additional layer of complexity. This review seeks to provide molecular insights into mechanisms underlying PC bone metastasis development and progression.

Chemotactic signaling pathways in prostate cancer: Implications in the tumor microenvironment and as potential therapeutic targets

Prostate cancer (PCa) stands as a significant global health concern, ranking among the leading causes of cancer deaths in men. While there are several treatment modalities for localized PCa, metastatic castration-resistant PCa (mCRPC) remains incurable. Despite therapeutic advancements showing promise in mCRPC, their impact on overall survival has been limited. This chapter explores the process by which tumors form, reviews our current understanding of PCa progression to mCRPC, and addresses the challenges of boosting anti-tumor immune responses in these tumors. It specifically discusses how chemotactic signaling affects the tumor microenvironment and its role in immune evasion and cancer progression. The chapter further examines the rationale of directly or indirectly targeting these pathways as adjuvant therapies for mCRPC, highlighting recent pre-clinical and clinical studies currently underway. The discussion emphasizes the potential of targeting specific chemokines and chemokine receptors as combination therapies with mainstream treatments for PCa and mCRPC to maximize long-term survival for this deadly disease.

High-Dimensional Analyses Reveal IL15 Enhances Activation of Sipuleucel-T Lymphocyte Subsets and Reverses Immunoresistance

Sipuleucel-T (sip-T) is the only FDA-approved autologous cellular immunotherapy for metastatic castration-resistant prostate cancer (mCRPC). To elucidate parameters of the response profile to this therapy, we report high-dimensional analyses of sip-T using cytometry by time of flight (CyTOF) and show a lymphoid predominance, with CD3+ T cells constituting the highest proportion (median ∼60%) of sip-T, followed by B cells, and natural killer (NK) and NKT cells. We hypothesized that treatment of sip-T with homeostatic cytokines known to activate/expand effector lymphocytes could augment efficacy against prostate tumors. Of the cytokines tested, IL15 was the most effective at enhancing activation and proliferation of effector lymphocytes, as well as augmenting tumor cytotoxicity in vitro. Co-culture of sip-T with IL15 and control or prostate-relevant antigens showed substantial activation and expansion of CD8+ T cells and NKT cells in an antigen-specific manner. Adoptive transfer of IL15-treated sip-T into NSG mice resulted in more potent prostate tumor growth inhibition compared with control sip-T. Evaluation of tumor-infiltrating lymphocytes revealed a 2- to 14-fold higher influx of sip-T and a significant increase in IFNγ producing CD8+ T cells and NKT cells within the tumor microenvironment in the IL15 group. In conclusion, we put forward evidence that IL15 treatment can enhance the functional antitumor immunity of sip-T, providing rationale for combining IL15 or IL15 agonists with sip-T to treat patients with mCRPC.

Evolving Tumor Characteristics and Smart Nanodrugs for Tumor Immunotherapy

Typical physiological characteristics of tumors, such as weak acidity, low oxygen content, and upregulation of certain enzymes in the tumor microenvironment (TME), provide survival advantages when exposed to targeted attacks by drugs and responsive nanomedicines. Consequently, cancer treatment has significantly progressed in recent years. However, the evolution and adaptation of tumor characteristics still pose many challenges for current treatment methods. Therefore, efficient and precise cancer treatments require an understanding of the heterogeneity degree of various factors in cancer cells during tumor evolution to exploit the typical TME characteristics and manage the mutation process. The highly heterogeneous tumor and infiltrating stromal cells, immune cells, and extracellular components collectively form a unique TME, which plays a crucial role in tumor malignancy, including proliferation, invasion, metastasis, and immune escape. Therefore, the development of new treatment methods that can adapt to the evolutionary characteristics of tumors has become an intense focus in current cancer treatment research. This paper explores the latest understanding of cancer evolution, focusing on how tumors use new antigens to shape their "new faces"; how immune system cells, such as cytotoxic T cells, regulatory T cells, macrophages, and natural killer cells, help tumors become "invisible", that is, immune escape; whether the diverse cancer-associated fibroblasts provide support and coordination for tumors; and whether it is possible to attack tumors in reverse. This paper discusses the limitations of targeted therapy driven by tumor evolution factors and explores future strategies and the potential of intelligent nanomedicines, including the systematic coordination of tumor evolution factors and adaptive methods, to meet this therapeutic challenge.

Mass Spectrometry-Based Proteomics Identifies Serpin B9 as a Key Protein in Promoting Bone Metastases in Lung Cancer

Bone metastasis (BM) is one of the most common complications of advanced cancer. Immunotherapy for bone metastasis of lung cancer (LCBM) is not so promising and the immune mechanisms are still unknown. Here, we utilized a model of BM by injecting cancer cells through caudal artery (CA) to screen out a highly bone metastatic derivative (LLC1-BM3) from a murine lung cancer cell line LLC1. Mass spectrometry-based proteomics was performed in LLC1-parental and LLC1-BM3 cells. Combining with prognostic survival information from patients with lung cancer, we identified serpin B9 (SB9) as a key factor in BM. Molecular characterization showed that SB9 overexpression was associated with poor prognosis and high bone metastatic burden in lung cancer. Moreover, SB9 could increase the ability of lung cancer cells to metastasize to the bone. The mechanistic studies revealed that tumor-derived SB9 promoted BM through an immune cell-dependent way by inactivating granzyme B, manifesting with the decreased infiltration of cytotoxic T cells and increased expression level of exhausted markers. A specific SB9-targeting inhibitor [1,3-benzoxazole-6-carboxylic acid (BTCA)] significantly suppressed LCBM in the CA mouse model. This study reveals that SB9 may serve as a therapeutic target and potential prognostic marker for patients with LCBM.

IMPLICATIONS

SB9 as a therapeutic target for LCBM.

PARP inhibitor plus radiotherapy reshape the immune suppressive microenvironment and potentiate the efficacy of immune checkpoint inhibitors in tumors with IDH1 mutation

Isocitrate dehydrogenase 1 mutant (IDH1mut) tumors respond poorly to immunotherapy, but are more sensitive to chemoradiotherapy and poly (ADP-ribose) polymerase inhibition (PARPi). Accordingly, some efforts have aimed to capitalize on the IDH1 mutation rather than reverse it. Moreover, radiotherapy (RT) and PARPi can stimulate antitumor immunity, raising the possibility of reversing the immunosuppression caused by IDH1 mutation while killing the tumor. To assess this possibility, we treated IDH1mut tumors and cells with RT + PARPi. RT + PARPi showed enhanced efficacy over either modality alone both in vitro and in vivo. RT + PARPi induced more DNA damage and activated the cGAS-STING pathway more. IFNβ, CXCL10, and CCL5 were also more highly expressed at both the mRNA and protein levels. In two different tumor models, RT + PARPi increased infiltration and cytolytic function of CD8+ T cells, with one model also showing increased CD8+T cell proliferation. RT+PARPi also increased PD-L1 expression and enhanced checkpoint inhibition. Knocking out cGAS reversed the increased CD8+ T cell infiltration and the antitumor effect of RT+PARPi. We conclude that RT + PARPi reshapes the IDH1mut tumor immunosuppressive microenvironment, thereby augmenting checkpoint inhibition.

Regulation and impact of tumor-specific CD4+ T cells in cancer and immunotherapy

CD4+ T cells are crucial in generating and sustaining immune responses. They orchestrate and fine-tune mammalian innate and adaptive immunity through cell-based interactions and the release of cytokines. The role of these cells in contributing to the efficacy of antitumor immunity and immunotherapy has just started to be uncovered. Yet, many aspects of the CD4+ T cell response are still unclear, including the differentiation pathways controlling such cells during cancer progression, the external signals that program them, and how the combination of these factors direct ensuing immune responses or immune-restorative therapies. In this review, we focus on recent advances in understanding CD4+ T cell regulation during cancer progression and the importance of CD4+ T cells in immunotherapies.

The safety and efficacy of systemic delivery of a new liver-de-targeted TGFβ signaling inhibiting adenovirus in an immunocompetent triple negative mouse mammary tumor model

Aberrant TGFβ signaling is linked to metastasis and tumor immune escape of many cancers including metastatic triple negative breast cancer (mTNBC). Previously, we have found that oncolytic adenoviruses expressing a TGFβ signaling inhibitory protein (sTGFβRIIFc) induced immune activation in a mouse TNBC (4T1) immunocompetent subcutaneous model with intratumoral injection. Systemic administration of adenoviruses can be a superior route to treat mTNBC but faces the challenges of increased toxicity and viral clearance. Thus, we created a liver-de-targeted sTGFβRIIFc- and LyP-1 peptide-expressing adenovirus (mHAdLyp.sT) with enhanced breast cancer cell tropism. Its safety and immune response features were profiled in the 4T1 model. Our data showed that the systemic administration of mHAdLyp.sT resulted in reduced hepatic and systemic toxicity. mHAdLyp.sT was also effective in increasing Th1 cytokines and anti-tumor cell populations by cytokine analysis, spleen/tumor qRT-PCR, and flow cytometry. We further tested the therapeutic effects of mHAdLyp.sT alone and in combination with immune checkpoint inhibitors (ICIs). mHAdLyp.sT alone and with all ICI combinations elicited significant inhibition of lung metastasis by histological analysis. When mHAdLyp.sT was combined with both anti-PD-1 and anti-CTLA-4 antibodies, primary 4T1 tumor growth was also significantly inhibited. We are confident in advancing this new treatment option for mTNBC.

Clinical and translational attributes of immune-related adverse events

With immune checkpoint inhibitors (ICIs) becoming the mainstay of treatment for many cancers, managing their immune-related adverse events (irAEs) has become an important part of oncological care. This Review covers the clinical presentation of irAEs and crucial aspects of reversibility, fatality and long-term sequelae, with special attention to irAEs in specific patient populations, such as those with autoimmune diseases. In addition, the genetic basis of irAEs, along with cellular and humoral responses to ICI therapy, are discussed. Detrimental effects of empirically used high-dose steroids and second-line immunosuppression, including impaired ICI effectiveness, call for more tailored irAE-treatment strategies. We discuss open therapeutic challenges and propose potential avenues to accelerate personalized management strategies and optimize outcomes.

B Cells and IL-21-Producing Follicular Helper T Cells Cooperate to Determine the Dynamic Alterations of Premetastatic Tumor Draining Lymph Nodes of Breast Cancer

Metastasis is the major cause of cancer-related death, and lymph node is the most common site of metastasis in breast cancer. However, the alterations that happen in tumor-draining lymph nodes (TDLNs) to form a premetastatic microenvironment are largely unknown. Here, we first report the dynamic changes in size and immune status of TDLNs before metastasis in breast cancer. With the progression of tumor, the TDLN is first enlarged and immune-activated at early stage that contains specific antitumor immunity against metastasis. The TDLN is then contracted and immunosuppressed at late stage before finally getting metastasized. Mechanistically, B and follicular helper T (Tfh) cells parallelly expand and contract to determine the size of TDLN. The activation status and specific antitumor immunity of CD8+ T cells in the TDLN are determined by interleukin-21 (IL-21) produced by Tfh cells, thus showing parallel changes. The turn from activated enlargement to suppressed contraction is due to the spontaneous contraction of germinal centers mediated by follicular regulatory T cells. On the basis of the B-Tfh-IL-21-CD8+ T cell axis, we prove that targeting the axis could activate TDLNs to resist metastasis. Together, our findings identify the dynamic alterations and regulatory mechanisms of premetastatic TDLNs of breast cancer and provide new strategies to inhibit lymph node metastasis.

Case report: Exceptional and durable response to Radium-223 and suspension of androgen deprivation therapy in a metastatic castration-resistant prostate cancer patient

Despite the development of new therapies in the last few years, metastatic prostate cancer (PCa) is still a lethal disease. Radium-223 (Ra-223) is approved for patients with advanced castration-resistant prostate cancer (CRPC) with bone metastases and no visceral disease. However, patients' outcomes are heterogenous, and there is lack of validated predictive biomarkers of response, while biomarkers for early identification of patients who benefit from treatment are limited. This case report describes a remarkable and durable response to Ra-223 in a CRPC patient with bone metastases who had rapidly progressed to many previous therapies; this response is now lasting for 5 years even after having stopped backbone androgen deprivation therapy (ADT). Here, we present the clinical course of this exceptional response, as well as comprehensive genomic and histopathology analyses on sequential biopsies acquired before and after therapy. Additionally, we review current knowledge on predictive and response biomarkers to Ra-223 in metastatic prostate cancer.

Pan-cancer and multi-omics analyses revealed the diagnostic and prognostic value of BAZ2A in liver cancer

BAZ2A, an epigenetic regulatory factor that affects ribosomal RNA transcription, has been shown to be highly expressed in several cancers and promotes tumor cell migration. This study explored the expression and mechanism of BAZ2A in tumorigenesis at the pan-cancer level. The Cancer Genome Atlas, Gene Expression Omnibus databases and TIMER2.0, cBioPortal and other tools were used to analyze the level of expression of BAZ2A in various tumor tissues and to examine the relationship between BAZ2A and survival, prognosis, mutation and immune invasion. In vitro experiments were performed to assess the function of BAZ2A in cancer cells. Using combined transcriptome and proteome analysis, we examined the possible mechanism of BAZ2A in tumors. BAZ2A exhibited high expression levels in multiple tumor tissues and displayed a significant association with cancer patient prognosis. The main type of BAZ2A genetic variation in cancer is gene mutation. Downregulation of BAZ2A inhibited proliferation, migration, and invasion and promoted apoptosis in LM6 liver cancer cell. The mechanism of BAZ2A in cancer development may involve lipid metabolism. These results help expand our understanding of BAZ2A in tumorigenesis and development and suggest BAZ2A may serve as a prognostic and diagnostic factor in several cancers.

Dynamic Responses of Circulating T Cells After Stereotactic Body Radiation Therapy for Bone Metastasis in Patients With Breast Cancer

PURPOSE

Preclinical studies have shown that radiation therapy modulates antitumor immune responses. However, circulating T-cell responses after radiation therapy in patients with cancer have been poorly characterized. This study aims to explore the changes in circulating T cells after stereotactic body radiation therapy (SBRT).

METHODS AND MATERIALS

Peripheral blood samples of 30 patients with breast cancer who underwent SBRT for bone metastasis were analyzed using multicolor flow cytometry. Phenotypes of PD-1+ CD8+ T cells and regulatory T (TREG) cells were examined. Additionally, plasma protein levels were analyzed using a bead-based immunoassay.

RESULTS

Circulating PD-1+ CD8+ T cells, which are enriched for tumor-specific clonotypes, were activated at 1 week after SBRT. However, circulating TREG cells were also activated after SBRT; this pattern was also evident among effector Foxp3hiCD45RA- TREG cells. We observed no difference in T-cell responses according to the fraction size and number. Notably, activation of TREG cells was more prominent in patients who experienced greater activation of PD-1+ CD8+ T cells. Plasma level changes in TGF-β1, soluble CTLA-4, and soluble 4-1BB at 1 week after SBRT were associated with PD-1+ CD8+ T-cell responses. Activation of TREG cells at 1 week after SBRT was associated with worse progression-free survival. Clinical factors including molecular subtype were not associated with the T-cell responses.

CONCLUSIONS

SBRT induced activation of both potentially tumor-specific CD8+ T cells and TREG cells, which were tightly associated with each other. These results may support the use of TREG cell-modulating strategies with SBRT to improve the antitumor immune response.

Multiple influence of immune cells in the bone metastatic cancer microenvironment on tumors

Bone is a common organ for solid tumor metastasis. Malignant bone tumor becomes insensitive to systemic therapy after colonization, followed by poor prognosis and high relapse rate. Immune and bone cells in situ constitute a unique immune microenvironment, which plays a crucial role in the context of bone metastasis. This review firstly focuses on lymphatic cells in bone metastatic cancer, including their function in tumor dissemination, invasion, growth and possible cytotoxicity-induced eradication. Subsequently, we examine myeloid cells, namely macrophages, myeloid-derived suppressor cells, dendritic cells, and megakaryocytes, evaluating their interaction with cytotoxic T lymphocytes and contribution to bone metastasis. As important components of skeletal tissue, osteoclasts and osteoblasts derived from bone marrow stromal cells, engaging in 'vicious cycle' accelerate osteolytic bone metastasis. We also explain the concept tumor dormancy and investigate underlying role of immune microenvironment on it. Additionally, a thorough review of emerging treatments for bone metastatic malignancy in clinical research, especially immunotherapy, is presented, indicating current challenges and opportunities in research and development of bone metastasis therapies.

Shaping immune landscape of colorectal cancer by cholesterol metabolites

Cancer immunotherapies have achieved unprecedented success in clinic, but they remain largely ineffective in some major types of cancer, such as colorectal cancer with microsatellite stability (MSS CRC). It is therefore important to study tumor microenvironment of resistant cancers for developing new intervention strategies. In this study, we identify a metabolic cue that determines the unique immune landscape of MSS CRC. Through secretion of distal cholesterol precursors, which directly activate RORγt, MSS CRC cells can polarize T cells toward Th17 cells that have well-characterized pro-tumor functions in colorectal cancer. Analysis of large human cancer cohorts revealed an asynchronous pattern of the cholesterol biosynthesis in MSS CRC, which is responsible for the abnormal accumulation of distal cholesterol precursors. Inhibiting the cholesterol biosynthesis enzyme Cyp51, by pharmacological or genetic interventions, reduced the levels of intratumoral distal cholesterol precursors and suppressed tumor progression through a Th17-modulation mechanism in preclinical MSS CRC models. Our study therefore reveals a novel mechanism of cancer-immune interaction and an intervention strategy for the difficult-to-treat MSS CRC.

AMG 509 (Xaluritamig), an Anti-STEAP1 XmAb 2+1 T-cell Redirecting Immune Therapy with Avidity-Dependent Activity against Prostate Cancer

The tumor-associated antigen STEAP1 is a potential therapeutic target that is expressed in most prostate tumors and at increased levels in metastatic castration-resistant prostate cancer (mCRPC). We developed a STEAP1-targeted XmAb 2+1 T-cell engager (TCE) molecule, AMG 509 (also designated xaluritamig), that is designed to redirect T cells to kill prostate cancer cells that express STEAP1. AMG 509 mediates potent T cell-dependent cytotoxicity of prostate cancer cell lines in vitro and promotes tumor regression in xenograft and syngeneic mouse models of prostate cancer in vivo. The avidity-driven activity of AMG 509 enables selectivity for tumor cells with high STEAP1 expression compared with normal cells. AMG 509 is the first STEAP1 TCE to advance to clinical testing, and we report a case study of a patient with mCRPC who achieved an objective response on AMG 509 treatment.

SIGNIFICANCE

Immunotherapy in prostate cancer has met with limited success due to the immunosuppressive microenvironment and lack of tumor-specific targets. AMG 509 provides a targeted immunotherapy approach to engage a patient's T cells to kill STEAP1-expressing tumor cells and represents a new treatment option for mCRPC and potentially more broadly for prostate cancer. See related commentary by Hage Chehade et al., p. 20. See related article by Kelly et al., p. 76. This article is featured in Selected Articles from This Issue, p. 5.

Preclinical Modeling of Pathway-Targeted Therapy of Human Lung Cancer in the Mouse

Animal models, particularly genetically engineered mouse models (GEMMs), continue to have a transformative impact on our understanding of the initiation and progression of hematological malignancies and solid tumors. Furthermore, GEMMs have been employed in the design and optimization of potent anticancer therapies. Increasingly, drug responses are assessed in mouse models either prior, or in parallel, to the implementation of precision medical oncology, in which groups of patients with genetically stratified cancers are treated with drugs that target the relevant oncoprotein such that mechanisms of drug sensitivity or resistance may be identified. Subsequently, this has led to the design and preclinical testing of combination therapies designed to forestall the onset of drug resistance. Indeed, mouse models of human lung cancer represent a paradigm for how a wide variety of GEMMs, driven by a variety of oncogenic drivers, have been generated to study initiation, progression, and maintenance of this disease as well as response to drugs. These studies have now expanded beyond targeted therapy to include immunotherapy. We highlight key aspects of the relationship between mouse models and the evolution of therapeutic approaches, including oncogene-targeted therapies, immunotherapies, acquired drug resistance, and ways in which successful antitumor strategies improve on efficiently translating preclinical approaches into successful antitumor strategies in patients.

Novel hormone therapy and coordination of care in high-risk biochemically recurrent prostate cancer

Biochemical recurrence (BCR) occurs in 20-50% of patients with prostate cancer (PCa) undergoing primary definitive treatment. Patients with high-risk BCR have an increased risk of metastatic progression and subsequent PCa-specific mortality, and thus could benefit from treatment intensification. Given the increasing complexity of diagnostic and therapeutic modalities, multidisciplinary care (MDC) can play a crucial role in the individualized management of this patient population. This review explores the role for MDC when evaluating the clinical evidence for the evolving definition of high-risk BCR and the emerging therapeutic strategies, especially with novel hormone therapies (NHTs), for patients with either high-risk BCR or oligometastatic PCa. Clinical studies have used different characteristics to define high-risk BCR and there is no consensus regarding the definition of high-risk BCR nor for management strategies. Next-generation imaging and multigene panels offer potential enhanced patient identification and precision-based decision-making, respectively. Treatment intensification with NHTs, either alone or combined with radiotherapy or metastasis-directed therapy, has been promising in clinical trials in patients with high-risk BCR or oligometastases. As novel risk-stratification and treatment options as well as evidence-based literature evolve, it is important to involve a multidisciplinary team to identify patients with high-risk features at an earlier stage, and make informed decisions on the treatments that could optimize their care and long-term outcomes. Nevertheless, MDC data are scarce in the BCR or oligometastatic setting. Efforts to integrate MDC into the standard management of this patient population are needed, and will likely improve outcomes across this heterogeneous PCa patient population.