Demystifying the CXCR4 conundrum in cancer biology: Beyond the surface signaling paradigm

Immunoexpression of CXCL12 and CXCR4 in oral tongue squamous cell carcinoma of young and older patients

PURPOSE

This study analyzed the immunoexpression of C-X-C chemokine ligand 12 (CXCL12) and C-X-C chemokine receptor 4 (CXCR4) in oral tongue squamous cell carcinoma (OTSCC) of young (≤ 45 years) and older (≥ 60 years) patients and correlated the findings with clinicopathological parameters (sex, tumor size, regional metastasis, clinical stage, and histopathological grade of malignancy).

METHODS

Forty OTSCC cases (20 diagnosed in young patients and 20 diagnosed in older patients) were selected. Cytoplasmic (CXCL12 and CXCR4) and nuclear (CXCR4) staining percentages in epithelial and stromal cells were assessed at the invasive tumor front.

RESULTS

Low median percentages of CXCL12 positivity were observed in epithelial and stromal cells of OTSCC in both age groups. In stromal cells, expression of this chemokine was higher in older individuals compared to young individuals (p = 0.026). Expression of CXCR4 in neoplastic cells was more frequent in older individuals, with higher median percentages of cytoplasmic (p = 0.023) and nuclear (p = 0.001) positivity compared to young individuals. In stromal cells, older individuals exhibited a significantly higher cytoplasmic expression of CXCR4 (p < 0.001). No significant differences in CXCL12 or CXCR4 immunoexpression according to clinicopathological parameters was observed in either age group (p > 0.05). Positive correlations between cytoplasmic and nuclear expressions of CXCR4 were found in young (r = 0.580; p = 0.007) and older individuals (r = 0.476;p = 0.034).

CONCLUSION

The results suggest the participation of CXCR4 in the development of OTSCC, especially in older individuals. The findings also support possible age-related differences in the pathogenesis of this malignant neoplasm. Nevertheless, this protein may not be involved in the progression of OTSCC.

Inhibition of Abdominal Aortic Aneurysm Progression Through the CXCL12/CXCR4 Axis via MiR206-3p Sponge

Notably, the C-X-C Motif Chemokine Ligand 12/C-X-C Chemokine Receptor Type 4 (CXCL12/CXCR4) signalling pathway's activation is markedly increased in a mouse model of abdominal aortic aneurysms (AAA). Nonetheless, the precise contribution of this pathway to AAA development remains to be elucidated. The AAA mouse model was induced by local incubation with elastase and oral administration of β-aminopropionitrile. The activity level of the CXCL12/CXCR4 axis was evaluated in both human AAA patients and the mouse model. Smooth muscle cell lineage tracing determined the expression and localisation of CXCR4 in normal aorta and AAA tissue. By transfecting the MiR206-3p sponge to reduce the level of MiR206-3p in AAA, the effects of the CXCL12/CXCR4 pathway on AAA progression as well as the apoptosis and phenotypic transformation of vascular smooth muscle cells (VSMCs) were studied in vivo and in vitro. Single-cell RNA sequencing analysis, serum ELISA, and in vivo experiments indicate a pronounced activation of the CXCL12/CXCR4 axis in both AAA patients and the mouse model. Specific blocking of the CXCL12/CXCR4 axis significantly inhibited further expansion and rupture of the abdominal aorta and reduced the infiltration of inflammatory cells in the aorta and inhibited the phenotypic transformation of contractile VSMCs into a macrophage-like state. Our findings propose that MiR206-3p sponge represents an innovative therapeutic strategy to attenuate AAA progression and rupture risk, primarily through the suppression of the CXCL12/CXCR4 signalling pathway.

Mechanisms of traditional Chinese medicine in the treatment and prevention of gastric cancer

BACKGROUND

Gastric cancer (GC) ranks as the fifth most prevalent malignancy worldwide. Conventional treatments, including radiotherapy and chemotherapy, often induce severe side effects and significant adverse reactions, and they may also result in drug resistance. Consequently, there is a critical need for the development of new therapeutic agents. Traditional Chinese Medicine (TCM) and natural products are being extensively researched due to their low toxicity, multi-targeted approaches, and diverse pathways. Scholars are increasingly focusing on identifying active anticancer components within TCM.

PURPOSE

This review aims to summarise research conducted over the past 14 years on the treatment of GC using TCM. The focus is on therapeutic targets, mechanisms, and efficacy of Chinese medicine and natural products, including monomer compounds, extracts or analogues, and active ingredients.

METHODS

Relevant articles on TCM and GC were retrieved from PubMed using appropriate keywords. The collected articles were screened and classified according to the types of TCM, with an emphasis on the molecular mechanisms underlying the treatment of GC.

RESULTS

The research on TCM indicates that TCM and natural products can effectively inhibit the metastasis, proliferation, and invasion of tumour cells. They can also induce apoptosis, autophagy and improve the chemosensitivity of drug-resistant cells. Additionally, injections derived from Chinese herbal medicine, when used as an adjunct to conventional chemotherapy, can significantly improve the prognosis of GC patients by reducing chemotherapy toxicity.

CONCLUSION

This review summarises the progress of TCM treatment of GC over the past 14 years, and discusses its therapeutic application of GC, which proves that TCM is a promising treatment strategy for GC in the future.

CXCR4 influences PUFA desaturation and oxidative stress injury in experimental prostatitis mice by activating Fads2 via PPARγ

Chronic prostatitis-induced excessive inflammation and oxidative stress (OS) damage substantially affect men's quality of life. However, its treatment remains a major clinical challenge. Therefore, the identification of drugs that can decrease chronic prostatitis and oxidative stress targets is urgent and essential. CXCR4 is a classic chemokine receptor that is crucially associated with the occurrence and development of inflammation. This investigation aimed to elucidate how CXCR4 affects prostatitis regression and progression. The effect of CXCR4 on chronic prostatitis was evaluated by HE staining, immunohistochemistry, immunofluorescence, PCR, and TUNEL analyses. Furthermore, CXCR4 influence on metabolism was also evaluated by monitoring body weight, body temperature, food intake, and LC/MS. Additionally, chromatin immunoprecipitation, Western blot, and double luciferase reporter gene assays were carried out to elucidate the mechanism by which CXCR4 modulates Fads2 transcription by PPARγ. Lastly, ROS, DHE, mito-tracker, and ATP were utilized to validate the α-linolenic acid's protective effect against OS in prostate epithelial cells. It was revealed that the inhibition of CXCR4 can effectively alleviate prostatitis in mice. Furthermore, downregulating CXCR4 expression can markedly reduce the inflammatory cell infiltration in mouse prostates, decrease the elevated levels of DNA damage markers,MDA and 4-HNE, and mitigate apoptosis of prostatic epithelial cells. Moreover, treatment of CXCR4 knockdown mice with a PPARγ inhibitor revealed different degrees of changes in the above phenotypes. Mechanistically, the PPARγ protein translocates to the nucleus and serves as a transcription factor to regulate Fads2 expression, thereby altering PUFA metabolism. Additionally, in vitro experiments indicated that α-linolenic acid can effectively alleviate OS damage and RWPE-1 cell apoptosis by protecting mitochondrial function and enhancing the antioxidant capacity of prostatic epithelial cells. In conclusion, reducing the levels of CXCR4 can alleviate inflammation and OS damage in chronic prostatitis.

Intestinal flora and inflammatory bowel disease: Causal relationships and predictive models

BACKGROUND

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is significantly influenced by intestinal flora. Understanding the genetic and microbiotic interplay is crucial for IBD prediction and treatment.

METHODS

We used Mendelian randomization (MR), transcriptomic analysis, and machine learning techniques, integrating data from the MiBioGen Consortium and various GWAS datasets. SNPs associated with intestinal flora were mapped to genes, with LASSO regression refining gene selection. Differentially expressed genes (DEGs) and immune infiltration patterns were identified through transcriptomic analysis. Six machine learning models were used for predictive modeling.

FINDINGS

MR analysis identified 25 gut microbiota classifications causally related to IBD. SNP mapping and gene expression analysis highlighted 24 significant genes. Drug target MR and colocalization validated these genes' causal relationships with IBD. Key pathways identified included the PI3K-Akt signaling pathway and epithelial-mesenchymal transition. Immune infiltration analysis revealed distinct patterns between high and low LASSO score groups. Machine learning models demonstrated high predictive value, with soft voting enhancing reliability.

INTERPRETATION

By integrating MR, transcriptomic analysis, and sophisticated machine learning approaches, this study elucidates the causal relationships between intestinal flora and IBD. The application of machine learning not only enhanced predictive modeling but also offered new insights into IBD pathogenesis, highlighted potential therapeutic targets, and established a robust framework for predicting IBD onset.

An in vivo tumour organoid model based on the chick embryonic chorioallantoic membrane mimics key characteristics of the patient tissue: a proof-of-concept study

BACKGROUND

Patient-derived tumour organoids (PDOs) are highly advanced in vitro models for disease modelling, yet they lack vascularisation. To overcome this shortcoming, organoids can be inoculated onto the chorioallantoic membrane (CAM); the highly vascularised, not innervated extraembryonic membrane of fertilised chicken eggs. Therefore, we aimed to (1) establish a CAM patient-derived xenograft (PDX) model based on PDOs generated from the liver metastasis of a colorectal cancer (CRC) patient and (2) to evaluate the translational pipeline (patient - in vitro PDOs - in vivo CAM-PDX) regarding morphology, histopathology, expression of C-X-C chemokine receptor type 4 (CXCR4), and radiotracer uptake patterns.

RESULTS

The main liver metastasis of the CRC patient exhibited high 2-[18F]FDG uptake and moderate and focal [68Ga]Ga-Pentixafor accumulation in the peripheral part of the metastasis. Inoculation of PDOs derived from this region onto the CAM resulted in large, highly viable, and extensively vascularised xenografts, as demonstrated immunohistochemically and confirmed by high 2-[18F]FDG uptake. The xenografts showed striking histomorphological similarity to the patient's liver metastasis. The moderate expression of CXCR4 was maintained in ovo and was concordant with the expression levels of the patient's sample and in vitro PDOs. Following in vitro re-culturing of CAM-PDXs, growth, and [68Ga]Ga-Pentixafor uptake were unaltered compared to PDOs before transplantation onto the CAM. Although [68Ga]Ga-Pentixafor was taken up into CAM-PDXs, the uptake in the baseline and blocking group were comparable and there was only a trend towards blocking.

CONCLUSIONS

We successfully established an in vivo CAM-PDX model based on CRC PDOs. The histomorphological features and target protein expression of the original patient's tissue were mirrored in the in vitro PDOs, and particularly in the in vivo CAM-PDXs. The [68Ga]Ga-Pentixafor uptake patterns were comparable between in vitro, in ovo and clinical data and 2-[18F]FDG was avidly taken up in the patient's liver metastasis and CAM-PDXs. We thus propose the CAM-PDX model as an alternative in vivo model with promising translational value for CRC patients.

Deciphering the roles of the HMGB family in cancer: Insights from subcellular localization dynamics

The high-mobility group box (HMGB) family consists of four DNA-binding proteins that regulate chromatin structure and function. In addition to their intracellular functions, recent studies have revealed their involvement as extracellular damage-associated molecular patterns (DAMPs), contributing to immune responses and tumor development. The HMGB family promotes tumorigenesis by modulating multiple processes including proliferation, metabolic reprogramming, metastasis, immune evasion, and drug resistance. Due to the predominant focus on HMGB1 in the literature, little is known about the remaining members of this family. This review summarizes the structural, distributional, as well as functional similarities and distinctions among members of the HMGB family, followed by a comprehensive exploration of their roles in tumor development. We emphasize the distributional and functional hierarchy of the HMGB family at both the organizational and subcellular levels, with a focus on their relationship with the tumor immune microenvironment (TIME), aiming to prospect potential strategies for anticancer therapy.

CXCR7 activation evokes the anti-PD-L1 antibody against glioblastoma by remodeling CXCL12-mediated immunity

The interaction between glioblastoma cells and glioblastoma-associated macrophages (GAMs) influences the immunosuppressive tumor microenvironment, leading to ineffective immunotherapies. We hypothesized that disrupting the communication between tumors and macrophages would enhance the efficacy of immunotherapies. Transcriptomic analysis of recurrent glioblastoma specimens indicated an enhanced neuroinflammatory pathway, with CXCL12 emerging as the top-ranked gene in secretory molecules. Single-cell transcriptome profiling of naïve glioblastoma specimens revealed CXCL12 expression in tumor and myeloid clusters. An analysis of public glioblastoma datasets has confirmed the association of CXCL12 with disease and PD-L1 expression. In vitro studies have demonstrated that exogenous CXCL12 induces pro-tumorigenic characteristics in macrophage-like cells and upregulated PD-L1 expression through NF-κB signaling. We identified CXCR7, an atypical receptor for CXCL12 predominantly present in tumor cells, as a negative regulator of CXCL12 expression by interfering with extracellular signal-regulated kinase activation. CXCR7 knockdown in a glioblastoma mouse model resulted in worse survival outcomes, increased PD-L1 expression in GAMs, and reduced CD8+ T-cell infiltration compared with the control group. Ex vivo T-cell experiments demonstrated enhanced cytotoxicity against tumor cells with a selective CXCR7 agonist, VUF11207, reversing GAM-induced immunosuppression in a glioblastoma cell-macrophage-T-cell co-culture system. Notably, VUF11207 prolonged survival and potentiated the anti-tumor effect of the anti-PD-L1 antibody in glioblastoma-bearing mice. This effect was mitigated by an anti-CD8β antibody, indicating the synergistic effect of VUF11207. In conclusion, CXCL12 conferred immunosuppression mediated by pro-tumorigenic and PD-L1-expressing GAMs in glioblastoma. Targeted activation of glioblastoma-derived CXCR7 inhibits CXCL12, thereby eliciting anti-tumor immunity and enhancing the efficacy of anti-PD-L1 antibodies.

CXCR4 Expression as a Prognostic Biomarker in Soft Tissue Sarcomas

Poor long-term survival in localized high-risk soft tissue sarcomas (STSs) of the extremities and trunk highlights the need to identify new prognostic factors. CXCR4 is a chemokine receptor involved in tumor progression, angiogenesis, and metastasis. The aim of this study was to evaluate the association between CXCR4 expression in tumor tissue and survival in STSs patients treated with neoadjuvant therapy. CXCR4 expression was retrospectively determined by immunohistochemical analysis in serial specimens including initial biopsies, tumors post-neoadjuvant treatment, and tumors after relapse. We found that a positive cytoplasmatic expression of CXCR4 in tumors after neoadjuvant treatment was a predictor of poor recurrence-free survival (RFS) (p = 0.003) and overall survival (p = 0.019) in synovial sarcomas. We also found that positive nuclear CXCR4 expression in the initial biopsies was associated with poor RFS (p = 0.022) in undifferentiated pleomorphic sarcomas. In conclusion, our study adds to the evidence that CXCR4 expression in tumor tissue is a promising prognostic factor for STSs.

Targeting CXCR4 impaired T regulatory function through PTEN in renal cancer patients

BACKGROUND

Tregs trafficking is controlled by CXCR4. In Renal Cell Carcinoma (RCC), the effect of the new CXCR4 antagonist, R54, was explored in peripheral blood (PB)-Tregs isolated from primary RCC patients.

METHODS

PB-Tregs were isolated from 77 RCC patients and 38 healthy donors (HDs). CFSE-T effector-Tregs suppression assay, IL-35, IFN-γ, IL-10, TGF-β1 secretion, and Nrp-1+Tregs frequency were evaluated. Tregs were characterised for CTLA-4, PD-1, CD40L, PTEN, CD25, TGF-β1, FOXP3, DNMT1 transcriptional profile. PTEN-pAKT signalling was evaluated in the presence of R54 and/or triciribine (TCB), an AKT inhibitor. Methylation of TSDR (Treg-Specific-Demethylated-Region) was conducted.

RESULTS

R54 impaired PB-RCC-Tregs function, reduced Nrp-1+Tregs frequency, the release of IL-35, IL-10, and TGF-β1, while increased IFN-γ Teff-secretion. The CXCR4 ligand, CXCL12, recruited CD25+PTEN+Tregs in RCC while R54 significantly reduced it. IL-2/PMA activates Tregs reducing pAKT+Tregs while R54 increases it. The AKT inhibitor, TCB, prevented the increase in pAKT+Tregs R54-mediated. Moreover, R54 significantly reduced FOXP3-TSDR demethylation with DNMT1 and FOXP3 downregulation.

CONCLUSION

R54 impairs Tregs function in primary RCC patients targeting PTEN/PI3K/AKT pathway, reducing TSDR demethylation and FOXP3 and DNMT1 expression. Thus, CXCR4 targeting is a strategy to inhibit Tregs activity in the RCC tumour microenvironment.

The β2-adrenergic receptor associates with CXCR4 multimers in human cancer cells

While the existence and functional role of class C G-protein-coupled receptors (GPCR) dimers is well established, there is still a lack of consensus regarding class A and B GPCR multimerization. This lack of consensus is largely due to the inherent challenges of demonstrating the presence of multimeric receptor complexes in a physiologically relevant cellular context. The C-X-C motif chemokine receptor 4 (CXCR4) is a class A GPCR that is a promising target of anticancer therapy. Here, we investigated the potential of CXCR4 to form multimeric complexes with other GPCRs and characterized the relative size of the complexes in a live-cell environment. Using a bimolecular fluorescence complementation (BiFC) assay, we identified the β2 adrenergic receptor (β2AR) as an interaction partner. To investigate the molecular scale details of CXCR4-β2AR interactions, we used a time-resolved fluorescence spectroscopy method called pulsed-interleaved excitation fluorescence cross-correlation spectroscopy (PIE-FCCS). PIE-FCCS can resolve membrane protein density, diffusion, and multimerization state in live cells at physiological expression levels. We probed CXCR4 and β2AR homo- and heteromultimerization in model cell lines and found that CXCR4 assembles into multimeric complexes larger than dimers in MDA-MB-231 human breast cancer cells and in HCC4006 human lung cancer cells. We also found that β2AR associates with CXCR4 multimers in MDA-MB-231 and HCC4006 cells to a higher degree than in COS-7 and CHO cells and in a ligand-dependent manner. These results suggest that CXCR4-β2AR heteromers are present in human cancer cells and that GPCR multimerization is significantly affected by the plasma membrane environment.

68 Ga-Pentixafor PET/CT for in-vivo mapping of CXCR4 receptors as potential radiotheranostic targets in soft tissue and bone sarcoma: preliminary results

OBJECTIVE

To evaluate the diagnostic utility of 68 Ga-Pentixafor PET/CT for in vivo imaging of CXCR4 receptors in soft tissue/bone sarcoma.

METHODS

Ten (7M: 3F; mean age = 24.7 ± 14.2 years) consecutive patients with clinical and radiological evidence of bone/soft tissue sarcoma were recruited prospectively whole body 68 Ga-Pentixafor PET/CT imaging was performed at 60-min after tracer administration. After performing standard CT, PET acquisition from head to toe was done (3 min/bed position) in a caudocranial direction. PET/CT data was reconstructed and SUV max , SUV mean values, target-to-background ratio (TBR) and active tumor volume (cc) were computed for the tracer avid lesions. Histopathological and IHC analysis was performed on the surgically excised primary tumors. CXCR4 receptors' intensity was evaluated by visual scoring.

RESULTS

The mean SUV max and SUV mean values in the primary tumors were 4.80 ± 1.0 (3.9-7.7) and 2.40 ± 0.60 (0.9-4.0). The mean TBR and tumor volume (cc) were 1.84 ± 1.3 and 312.2 ± 285. Diagnosis of osteosarcoma in 7, chondrosarcoma, leiomyosarcoma and synovial sarcoma in 1 patient each was confirmed on HP analysis. Distant metastatic lesions were seen in 3/10 patients. Nuclear CXCR4 receptors' positivity was seen in 5, cytoplasmic in 4 and both pattern seen in 1 patient. The mean CXCR4 receptors' intensity was found to be 7.6 ± 2. The highest SUV max value of 7.7 was observed in the patient having both cytoplasmic and nuclear CXCR4 expression. SUV max was found to be poorly correlated ( r  = 0.441) with CXCR4 expression.

CONCLUSION

68 Ga-Pentixafor PET/CT detects CXCR4 receptors over-expressed in sarcoma, its radio-theranostics potential needs detailed evaluation.

Travelling under pressure - hypoxia and shear stress in the metastatic journey

Cancer cell invasion, intravasation and survival in the bloodstream are early steps of the metastatic process, pivotal to enabling the spread of cancer to distant tissues. Circulating tumor cells (CTCs) represent a highly selected subpopulation of cancer cells that tamed these critical steps, and a better understanding of their biology and driving molecular principles may facilitate the development of novel tools to prevent metastasis. Here, we describe key research advances in this field, aiming at describing early metastasis-related processes such as collective invasion, shedding, and survival of CTCs in the bloodstream, paying particular attention to microenvironmental factors like hypoxia and mechanical stress, considered as important influencers of the metastatic journey.

Co-Expression of Immunohistochemical Markers MRP2, CXCR4, and PD-L1 in Gallbladder Tumors Is Associated with Prolonged Patient Survival

Gallbladder cancer (GBC) is a rare pathology in Western countries. However, it constitutes a relevant health problem in Asia and Latin America, with a high mortality in middle-aged Chilean women. The limited therapeutic options for GBC require the identification of targetable proteins with prognostic value for improving clinical management support. We evaluated the expression of targetable proteins, including three epithelial tumor markers, four proteins associated with multidrug and apoptosis resistance, and eleven immunological markers in 241 primary gallbladder adenocarcinomas. We investigated correlations between tumor marker expression, the primary tumor staging, and GBC patients' survival using automated immunohistochemistry, a semi-automatic method for image analysis, univariate and multivariate statistical analyses, and machine learning algorithms. Our data show a significant association between the expression of MRP2 (p = 0.0028), CXCR4 (p = 0.0423), and PD-L1 (p = 0.0264), and a better prognosis for patients with late-stage primary tumors. The expression of the MRP2/CXCR4/PD-L1 cluster of markers discriminates among short-, medium-, and long-term patient survival, with an ROC of significant prognostic value (AUC = 0.85, p = 0.0012). Moreover, a high MRP2/CXCR4/PD-L1 co-expression is associated with increased survival time (30 vs. 6 months, p = 0.0025) in GBC patients, regardless of tumor stage. Hence, our results suggest that the MRP2/CXCR4/PD-L1 cluster could potentially be a prognostic marker for GBC.

Potential function of loliolide as a novel blocker of epithelial-mesenchymal transition in colorectal and breast cancer cells

Loliolide (LL), a naturally occurring monoterpenoid lactone isolated from Vicia tenuifolia Roth, can exhibit numerous pharmacological effects such as those related to anti-Parkinson, anti-oxidant, anti-cholinesterase, and anti-depressant. Epithelial-mesenchymal transition (EMT) plays a pivotal role in regulating tumor metastasis. CXCR4 and CXCR7 are G-protein-coupled receptors (GPRs), which can be stimulated by CXCL12. CXCL12/CXCR4/CXCXR7 axis can cause activation of multiple pathways including MAPKs, JAK/STAT pathway, and manganese superoxide dismutase (MnSOD) signaling. These events can initiate EMT process and induce cell invasion and migration. Here, we investigated whether LL can modulate the CXCR4 and CXCR7 and EMT process in colon cancer and breast cancer cells. We found that LL suppressed levels of CXCR4 and CXCR7, and exerted an inhibitory effect on these chemokines even after stimulation by CXCL12. LL suppressed expression of MnSOD and mesenchymal markers, whereas induced epithelial markers. In addition, LL significantly attenuated cellular invasion, migration, and metastasis. We noted that LL inhibited CXCR4/7 and EMT process even after stimulation of CXCL12 and MnSOD overexpression. Therefore, in this study, we provide evidences that targeting CXCR4/7 and MnSOD could inhibit the invasion, migration, and metastasis of cancer cells as well as negatively regulate the EMT process. Overall, our study suggested that LL might act as a potent suppressor of EMT process against colon and breast cancer cells.

CXC Chemokine Receptor Type 4 Antagonistic Gold Nanorods Induce Specific Immune Responses and Long-Term Immune Memory to Combat Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is highly challenging in its treatment because of the lack of the targeted markers. TNBC patients are not able to acquire benefits from endocrine therapy and targeted therapy except for chemotherapy. CXCR4 is highly expressed on TNBC cells that mediated the tumor cell metastasis as well as proliferation by the response of its ligand CXCL12, therefore holding promising potential of a candidate target for the treatment. In this work, a novel conjugate of CXCR4 antagonist peptide E5 and gold nanorods was fabricated (AuNRs-E5), which was applied to murine breast cancer tumor cells and an animal model, aiming to induce endoplasmic reticulum stress by endoplasmic reticulum-targeted photothermal immunological effects. Results showed that AuNRs-E5 could induce much more generation of damage-related molecular patterns in 4T1 cells under laser irradiation than AuNRs, which significantly promoted the maturation of dendritic cells and stimulated systematic anti-tumor immune responses by enhancing the infiltration of CD8⁺T cells into the tumor and tumor-draining lymph node, downregulating the regulatory T lymphocytes, and upregulating M1 macrophages in tumors, reversing the microenvironment from "cold" tumors to "hot" tumors. The administration of AuNRs-E5 with laser irradiation not only inhibited the tumor growth significantly but also exerted specific long immune responses to the triple-negative breast cancer tumor cells, which led to the prolonged survival of the mice and the specific immunological memory.

Differential Expression and Clinical Relevance of C-X-C Motif Chemokine Receptor 4 (CXCR4) in Renal Cell Carcinomas, Benign Renal Tumors, and Metastases

C-X-C Motif Chemokine Receptor 4 (CXCR4) is part of the human chemokine system and involved in progression and metastasis in renal cell carcinoma (RCC). However, the role of CXCR4 protein expression in RCC remains controversial. In particular, data regarding the subcellular distribution of CXCR4 in RCC and RCC metastasis as well as CXCR4 expression in renal tumors of variant histology are limited. The aim of the present study was the evaluation of the differential CXCR4 expression in RCC primary tumor and metastatic tissue as well as in variant renal histologies. In addition, the prognostic capacity of CXCR4 expression in organ-confined clear cell RCC (ccRCC) was evaluated. Three independent renal tumor cohorts (primary ccRCC cohort n1 = 64; cohort of various histological entities n2 = 146; metastatic RCC tissue cohort n3 = 92) were evaluated using tissue microarrays (TMA). After immunohistochemical staining for CXCR4, nuclear and cytoplasmic expression patterns were evaluated. CXCR4 expression was correlated with validated pathologic prognosticators, clinical data, and overall and cancer-specific survival. Positive cytoplasmic staining was observed in 98% of the benign and 38.9% of the malignant samples. Nuclear staining was positive for 94.1% of the benign samples and 83% of the malignant samples. The median cytoplasmic expression score was found to be higher in benign tissue than in ccRCC (130.00 vs. 0.00); median nuclear expression score analysis indicated the opposite (56.0 vs. 71.0). Within malignant subtypes, the highest expression score was seen in papillary renal cell carcinomas (cytoplasmic: 117.50, nuclear: 41.50). Within benign renal tumors, high cytoplasmic and nuclear CXCR4 expression scores were seen for oncocytomas (cytoplasmic: 100.00, nuclear: 31.00). Expression scores in RCC metastasis ranked between benign renal tissue and ccRCC in cytoplasmic and nuclear expression. Cytoplasmic CXCR4 expression was identified as a prognostic factor for OS and CSS (p = 0.042; p = 0.019). Multivariate analysis including clinicopathological parameters did not reveal an independent prognostic character of CXCR4 expression. CXCR4 expression differs significantly within benign lesions and renal neoplasms. Cytoplasmic and nuclear expression of CXCR4 could be detected across all RCC subtypes. The prognostic value of CXCR4 in ccRCC was confirmed in univariate analysis.