Tumor cell PD-L1 expression is a strong predictor of unfavorable prognosis in immune checkpoint therapy-naive clear cell renal cell cancer

PD-L1 expression in tumor and inflammatory cells is associated with favorable tumor features and favorable prognosis in muscle-invasive urothelial carcinoma of the bladder not treated by immune checkpoint inhibitors

BACKGROUND

A high level of PD-L1 expression is the most relevant predictive parameter for response to immune checkpoint inhibitor (CPI) therapy in urinary bladder cancer. Existing data on the relationship between PD-L1 expression and the natural course of disease are controversial and sparse.

METHODS

To expand our understanding of the relationship between PD-L1 expression and parameters of cancer aggressiveness, PD-L1 was analyzed on tissue microarrays containing 2710 urothelial bladder carcinomas including 512 patients with follow-up data who underwent radical cystectomy and follow-up therapies in the pre-immune checkpoint inhibitor therapy era.

RESULTS

Tumor cell positivity in ≥10% of cells were seen in 513 (20%) and an immune cell positivity occurred in 872 (34%) of 2566 interpretable cancers. PD-L1 positivity in tumor cells increased from pTaG2 low grade (0.9% positive) to pTaG3 high grade (4.1%; p = 0.0255) and was even higher in muscle-invasive (pT2-4) carcinomas (29.3%; p < 0.0001). However, within pT2-4 carcinomas, PD-L1 positivity was linked to low pT stage (p = 0.0028), pN0 (p < 0.0001), L0 status (p = 0.0005), and a better prognosis within 512 patients with cystectomy who never received CPIs (p = 0.0073 for tumor cells and p = 0.0086 for inflammatory cells). PD-L1 staining in inflammatory cells was significantly linked to PD-L1 staining in tumor cells (p < 0.0001) and both were linked to a positive p53 immunostaining (p < 0.0001).

CONCLUSION

It cannot be fully excluded that the strong statistical link between PD-L1 status and favorable histological tumor features as well as better prognosis could influence the outcome of studies evaluating CPIs in muscle-invasive urothelial carcinoma.

Modification of the tumor microenvironment enhances immunity with plasmid gene therapy

Local intratumor delivery with electroporation of low levels of plasmids encoding molecules, induces an antitumor effect without causing systemic toxicity. However, previous studies have predominately focused on the function of the delivered molecule encoded within the plasmid, and ignored the plasmid vector. In this study, we found vectors pUMVC3 and pVax1 induced upregulation of MHC class I (MHC-I) and PD-L1 on tumor cell surface. These molecules participate in a considerable number of immunoregulatory functions through their interactions with and activating inhibitory immune cell receptors. MHC molecules are well-known for their role in antigen (cross-) presentation, thereby functioning as key players in the communication between immune cells and tumor cells. Increased PD-L1 expression on tumor cells is an important monitor of tumor growth and the effectiveness of immune inhibitor therapy. Results from flow cytometry confirmed increased expression of MHC-I and PDL-1 on B16F10, 4T1, and KPC tumor cell lines. Preliminary animal data from tumor-bearing models, B16F10 melanoma, 4T1 breast cancer and KPC pancreatic cancer mouse models showed that tumor growth was attenuated after pUMVC3 intratumoral electroporation. Our data also documented that pSTAT1 signaling pathway might not be associated with plasmid vectors' function of upregulating MHC-I, PD-L1 on tumor cells.

Association between PD-L1 Expression and the Prognosis and Clinicopathologic Features of Non-Clear Cell Renal Cell Carcinoma

PD-L1 is one of the two programmed cell death 1 (PD-1) ligands and a part of an immune checkpoint system (PD-1/PD-L1) with widespread clinical application. The aim of this study was to investigate PD-L1 expression and its association with clinicopathological and prognostic significance in non-clear cell renal cell carcinoma (non-ccRCC) patients. A total of 41 papillary (pRCC) and 20 chromophobe (chRCC) RCC tumors were examined for PD-L1 expression by immunohistochemistry in the cancer cells and tumor-infiltrating mononuclear cells (TIMCs). PD-L1 positivity was detected in 36.6% pRCC and 85.0% chRCC cancer cells, while PD-L1 positivity was observed in 73.2% pRCC and 50.0% chRCC TIMCs. PD-L1 positivity in both pRCC and chRCC tumor cells was not correlated with any of the examined clinicopathological features, while PD-L1 positivity in TIMCs was associated with the age of patients with pRCC. During follow-up, the death was documented among 6 patients with pRCC. Papillary RCC patients with PD-L1-positive tumor cells were significantly associated with an increased risk of death compared with patients with PD-L1-negative cancer cells. A similar trend was observed when comparing PD-L1 expression in TIMCs. However, no differences in overall survival for PD-L1-positive pRCC patients with compared to PD-L1-negative patients were observed in tumor cells or TIMCs.

Management of Renal Cell Carcinoma: Promising Biomarkers and the Challenges to Reach the Clinic

The incidence of renal cell carcinoma (RCC) is increasing worldwide, yet research within this field is lagging behind other cancers. Despite increased detection of early disease as a consequence of the widespread use of diagnostic CT scans, 25% of patients have disseminated disease at diagnosis. Similarly, around 25% progress to metastatic disease following curatively intended surgery. Surgery is the cornerstone in the treatment of RCC; however, when the disease is disseminated, immunotherapy or immunotherapy in combination with a tyrosine kinase inhibitor is the patient's best option. Immunotherapy is a potent treatment, with durable treatment responses and potential to cure the patient, but only half of the patients benefit from the administered treatment, and there are currently no methods that can identify which patients will respond to immunotherapy. Moreover, there is a need to identify the patients in greatest risk of relapsing after surgery for localized disease and direct adjuvant treatment there. Even though several molecular biomarkers have been published to date, we are still lacking routinely used biomarkers to guide optimal clinical management. The purpose of this review is to highlight some of the most promising biomarkers, discuss the efforts made within this field to date, and describe the barriers needed to be overcome to have reliable and robust predictive and prognostic biomarkers in the clinic for renal cancer.

Bacterial Lipopolysaccharide Induces PD-L1 Expression and an Invasive Phenotype of Oral Squamous Cell Carcinoma Cells

BACKGROUND

Expression of programmed death ligand-1 (PD-L1) is related to the prognosis of many solid malignancies, including oral squamous cell carcinoma (OSCC), but the mechanism of PD-L1 induction remains obscure. In this study, we examined the expression of PD-L1 and partial epithelial-mesenchymal transition (pEMT) induced by bacterial lipopolysaccharide (LPS) in OSCC.

METHODS

The expression of Toll-like receptor 4 (TLR4) recognizing LPS in OSCC cell lines was analyzed. Moreover, the induction of PD-L1 expression by Porphyromonas gingivalis (P.g) or Escherichia coli (E. coli) LPS and EMT was analyzed by western blotting and RT-PCR. Morphology, proliferation, migration, and invasion capacities were examined upon addition of LPS. PD-L1 within EXOs was examined.

RESULTS

PD-L1 expression and pEMT induced by LPS of P.g or E. coli in TLR4-expressing OSCC cell lines were observed. Addition of LPS did not change migration, proliferation, or cell morphology, but increased invasive ability. Moreover, higher expression of PD-L1 was observed in OSCC EXOs with LPS.

CONCLUSION

Oral bacterial LPS is involved in enhanced invasive potential in OSCC cells, causing PD-L1 expression and induction of pEMT. The enhancement of PD-L1 expression after addition of LPS may be mediated by EXOs.

A signature based on chromatin regulation and tumor microenvironment infiltration in clear cell renal cell carcinoma

Aims: This research aimed to construct a signature based on chromatin regulation in localized clear cell renal cell carcinoma (ccRCC). Materials & methods: Non-negative matrix factorization clustering was performed on 438 localized ccRCC cases. The immune infiltration was generated by the single-sample gene set enrichment analysis algorithm. Survival analyses were performed using the Kaplan-Meier method, and the significance of the differences was determined using the log-rank test. The risk score was constructed based on the expression of chromatin regulators to quantify chromatin modification. Results: A score system based on chromatin modification was established. The high-risk subtype was characterized by increased tumor mutation burden, whereas a low-risk score was characterized by an increase in chromatin regulator expression and better overall survival. Conclusion: This research has constructed a signature based on chromatin regulation in localized ccRCC.

Immune checkpoint receptor VISTA on immune cells is associated with expression of T-cell exhaustion marker TOX and worse prognosis in renal cell carcinoma with venous tumor thrombus

PURPOSE

The study aimed to determine the expression of VISTA and TOX within venous tumor thrombus and primary clear cell renal cell carcinoma (ccRCC) and to assess their prognostic value.

METHODS

The study enrolled 82 patients with ccRCC and coexisting venous tumor thrombus treated radically from 2012 to 2019 in two tertiary centers. Tissue microarrays were prepared and stained with respective antibodies. The expression of markers was assessed separately on tumor cells (TCs) and/or tumor-associated immune cells (TAICs).

RESULTS

TOX expression was positively correlated with the percentage of VISTA-positive TAICs in venous thrombus (p = 0.011), but not in the primary tumor (p = 0.674). High TOX expression was associated with a higher percentage of PD-L1-positive TAICs in both compartments (p = 0.001, p = 0.011, respectively). Positive expression of VISTA on TAICs was associated with PD-L1 expression on TCs (p = 0.005) and TAICs (p = 0.004) in the primary tumor, and only with PD-L1 on TAICs in thrombus (p = 0.006). The presence of VISTA-positive TAICs in venous thrombus was significantly more common in females (p = 0.034), and positively correlated with metastases (p = 0.028), and tumor necrosis (p = 0.013). The cases with VISTA-positive TAICs in venous tumor thrombi had significantly shorter OS than VISTA-negative cases (p = 0.041).

CONCLUSION

For the first time, we demonstrated the expression of VISTA- and TOX-positive TAICs in the venous tumor thrombus. We found the association between immune checkpoint receptors and T cell exhaustion markers in both tumor mass and venous thrombus. Finally, we demonstrated that abundance of VISTA-positive TAICs in venous tumor thrombus correlates with worse outcomes in ccRCC.

Unveiling the Molecular Mechanisms Driving the Capsaicin-Induced Immunomodulatory Effects on PD-L1 Expression in Bladder and Renal Cancer Cell Lines

Simple Summary

Over time, capsaicin (CPS) has been considered both a potential anti-cancer and pro-cancer molecule. Hence, the diversity of CPS functioning has already been established. Now, exploration of its application with immunotherapies might open up a new avenue in cancer therapy. Herein, the application of CPS as an immunoadjuvant to overcome the tumor’s immune-escaping mechanisms or to increase immune checkpoint therapy has been approached. In bladder cancer, the interaction of CPS with its receptor TRPV1 increases PD-L1 expression, promoting a tumorigenic effect and also providing a target for anti-PD-1/PD-L1 immunotherapy. On the contrary, in renal cell carcinoma, CPS downregulates PD-L1 expression in a TRPV1-independent manner, suggesting a potential application of CPS as an immune-adjuvant in this type of cancer.

Abstract

The blockade of the PD-L1/PD-1 immune checkpoint has promising efficacy in cancer treatment. However, few patients with bladder cancer (BC) or renal cell carcinoma (RCC) respond to this approach. Thus, it is important to implement a strategy to stimulate the immune anti-tumor response. In this scenario, our study evaluated the effects of a low capsaicin (CPS) dose in BC and RCC cell lines. Western blot, qRT-PCR and confocal microscopy were used to assess PD-L1 mRNA and protein expression. Alterations to the cellular oxidative status and changes to the antioxidant NME4 levels, mRNA modulation of cytokines, growth factors, transcriptional factors and oncogene, and the activation of Stat1/Stat3 pathways were examined using Western blot, cytofluorimetry and qRT-PCR profiling assays. In BC, CPS triggers an altered stress oxidative-mediated DNA double-strand break response and increases the PD-L1 expression. On the contrary, in RCC, CPS, by stimulating an efficient DNA damage repair response, thus triggering protein carbonylation, reduces the PD-L1 expression. Overall, our results show that CPS mediates a multi-faceted approach. In modulating PD-L1 expression, there is a rationale for CPS exploitation as a stimulus that increases BC cells’ response to immunotherapy or as an immune adjuvant to improve the efficacy of the conventional therapy in RCC patients.