Search Results (32)

Objective: This study aimed to evaluate serum and salivary podoplanin (PDPN) levels in patients with oral cancer (OC) and oral leukoplakia (OL) and to investigate their potential role as diagnostic biomarkers in distinguishing between these conditions. Materials and Method: Ninety participants were enrolled: 30 healthy controls, 30 patients with OL, and 30 patients with histopathologically confirmed OC. All cases were recruited from the Department of Otorhinolaryngology, Cerrahpaşa Medical Faculty and Istanbul Atlas University Hospital. Demographic characteristics, comorbidities, and biochemical parameters were recorded. Serum and salivary PDPN levels were measured using the ELISA method. Results: Serum PDPN levels were significantly higher in the OC group (3.25 ± 0.80 ng/mL) compared with both OL (1.85 ± 0.56 ng/mL) and controls (0.98 ± 0.42 ng/mL) (p < 0.001). Salivary PDPN levels showed a similar pattern, being highest in OC (2.65 ± 0.75 ng/mL), followed by leukoplakia (1.40 ± 0.45 ng/mL), and controls (0.72 ± 0.30 ng/mL) (p < 0.001). Importantly, both serum and salivary PDPN concentrations increased progressively with increasing epithelial dysplasia severity among patients with OL (one-way ANOVA, p < 0.001). ROC analysis demonstrated excellent diagnostic accuracy for OC: AUC = 0.976 for serum PDPN (cut-off: 2.0 ng/mL; sensitivity 93.3%, specificity 100%) and AUC = 0.987 for salivary PDPN (cut-off 1.24 ng/mL; sensitivity 93.3%, specificity 95%). Conclusions: Serum and salivary PDPN levels were significantly elevated in patients with OC and demonstrated excellent diagnostic performance in distinguishing malignant lesions from OL and healthy controls. The observed stepwise increase in PDPN levels with dysplasia severity further supports its role in malignant transformation. Notably, salivary PDPN represents a non-invasive, practical, and reproducible biomarker that may aid in early detection and risk stratification of high-risk oral premalignant lesions. PDPN assessment could therefore complement clinical and histopathological evaluation, although larger prospective studies are warranted to validate its diagnostic and prognostic utility. Full article

Coronary artery disease remains a significant global health challenge, driven by a multifactorial pathophysiology, including immunological activation. The identification and management of potential risk factors are crucial for improving prevention opportunities. In this study, the role of novel, innate immune system response markers, such as podoplanin 38, in atherosclerosis was investigated. A total of 150 consecutive patients (87 (58%) male; median age of 68 (61–76) years) with chronic coronary symptoms (anginal equivalent, e.g., exertional dyspnea) who underwent clinical evaluation and de novo coronary angiography for a prospective single-center analysis were included. Demographic and clinical data, combined with echocardiographic and coronary angiography results, were analyzed in conjunction with laboratory results from admission, including serum podoplanin (PDPN) concentrations. Serum PDPN concentrations were significantly lower in the coronary artery disease group (238 (174–360) pg/mL) compared to the control group (428 (207–1381) pg/mL, p = 0.002). A negative correlation was observed between PDPN and the number of involved coronary arteries in the atherosclerotic process (R = −0.27, p < 0.01). In diabetic populations, glycemic hemoglobin (Hb1Ac) is correlated with the podoplanin concentration (r = −0.51, p = 0.001). A correlation between PDPN and the left ventricular ejection fraction was noted in both the control (r = 0.33, p < 0.01) and CAD groups (r = 0.37, p < 0.001). Podoplanin (PDPN) can be considered a novel marker for coronary atherosclerosis. Low serum podoplanin concentrations characterized patients with coronary artery disease. Full article

Objective: To evaluate the degree of current evidence through a systematic review and meta-analysis on the association between podoplanin overexpression and the malignant transformation of oral potentially malignant disorders (OPMDs). Methods: A systematic search was performed in the MEDLINE (through PubMed), Embase, Scopus, and Web of Science databases for primary-level research published before December 2024, strictly designed as longitudinal cohorts with follow up data, and no restrictions by language or publication date. The Quality in Prognosis Studies QUIPS tool (developed by the Cochrane Prognosis Methods Group) was applied in order to assess the methodological quality and risk of bias. Meta-analyses, subgroup meta-analyses, sensitivity, and small-study effects analyses were performed. Results: Twelve primary-level studies met the eligibility criteria and were included, which followed up 857 OPMDs patients over time. Podoplanin overexpression was significantly associated with an increased risk of the malignant transformation of OPMDs (RR = 3.64, 95% CI = 2.18–6.10, p < 0.001). Podoplanin also proved to be a valuable biomarker in the malignant transformation of all investigated OPMDs (oral leukoplakia: p < 0.001; erythroplakia: p = 0.05; oral lichen planus: p = 0.02; discoid lupus erythematosus: p = 0.009). In addition, podoplanin overexpression was significantly associated with an increased risk of cancer development in several study subgroups with methodological implications (anti-podoplanin D2-40 antibody: p < 0.001; membrane and cytoplasm staining: p < 0.001; antibody dilution at 1:100: p < 0.001; overnight incubation: p < 0.001; 4 °C incubation: p < 0.001; cut-off point > 1%: p < 0.001; low risk of bias: p < 0.001). Conclusions: This systematic review and meta-analysis, on the basis of the evidence, indicates that podoplanin overexpression is a predictor of an increased risk of malignant transformation in OPMDs, singularly in oral leukoplakias. Its evaluation using immunohistochemical methods would be advisable in pathology laboratories. Full article

Background: Over the last years, the phenomenon of entosis, a form of cell-in-cell structure, has been highlighted in various tumors, including poorly treatable breast or pancreatic cancers. Nevertheless, not only the biological properties, but also the molecular drivers of entosis remain unclear. Here, we evaluated SRC tyrosine kinase, a key proto-oncogene, and podoplanin (PDPN), a membrane glycoprotein, as potential regulators of entotic cell formation. Methods: In the study, two entosis-competent cell lines, BxPC-3 and MFC-7, originating from pancreatic and breast cancers, respectively, were used. SRC or PDPN genes were silenced using dedicated siRNA and the frequency of entotic structure formation was assessed using fluorescent staining and confocal imaging. Results: It was found that BxPC-3 cells deficient in PDPN are more prone to form entotic structures and that over 90% of all entotic figures formed by mixed PDPN⁺ and PDPN^- BxPC-3 cells involved PDPN-silenced cells. The SRC data supports this observation, as the suppressed entotic formation ability presented by SRC-deficient cells was linked with increased expression of PDPN. Even though the observed effects were mainly limited to BxPC-3 cells, as PDPN expression in MCF-7 cells is restricted, overall, the obtained data suggest a strong anti-entotic function of PDPN. Additionally, the performed Western blotting indicated the activation of ezrin-radixin-moesin (ERM) proteins in PDPN-deficient cells. Conclusions: Taken together, these data suggest that the negatively controlled PDPN-ERM axis may act as a molecular factor controlling the development of entotic structures and cells with naturally low PDPN expression may be more liable to form entoses. Full article

Background: Multiple mechanisms might lead to cancer-related hypercoagulability. In brain tumors, podoplanin, via its ability to activate platelets, seems to play a crucial role in developing venous thromboembolism (VTE). Different stimuli (including activated platelets) can trigger the release of prothrombotic neutrophil extracellular traps (NETs) by neutrophils. It remains to be elucidated whether podoplanin-induced platelet aggregates might also impact NET formation and subsequent hypercoagulability and thrombosis. Methods: Patients with glioma were enrolled in this prospective observational cohort study. The primary endpoint was VTE. Immunohistochemical staining of NETs (via citrullinated histone H3 [H3Cit]) and neutrophils (via myeloperoxidase [MPO]) was conducted in glioma specimens and correlated with intravascular platelet clusters (via CD61) and podoplanin. Results: In total, 154 patients were included. H3Cit+ tumor vessels were found in 45/154 cases. H3Cit were significantly associated with increased intravascular platelet clusters (CD61− vs. CD61+ vs. CD61++ vs. CD61+++: 3.7% (1/27) vs. 18.6% (11/59) vs. 39.4% (13/33) vs. 57.1% (20/35), p < 0.001) and podoplanin expression (PDPN− vs. PDPN+: 14.3% (7/49) vs. 36.2% (38/105), p = 0.007) in the tumor tissue. Furthermore, H3Cit+ tumor vessels were significantly associated with tumor-infiltrating MPO+ neutrophils (H3Cit− vs. H3Cit+, median [Q1-Q3]: 6.0 [3.3–12.3] vs. 12.5 [5.9–22.0] cells/mm², p < 0.001) and with D-dimer levels (H3Cit− vs. H3Cit+: 0.53 [0.32–1.10] vs. 0.84 [0.46–2.75] µg/mL, p = 0.034). The VTE risk was not linked to H3Cit+ tumor vessels (p = 0.613, log-rank). Conclusions: H3Cit in tumor vessels was not associated with VTE. However, H3Cit was linked to a local procoagulant phenotype in glioma, thereby potentially contributing to a systemic hypercoagulable state and thrombus formation. Full article

Background/Objectives: Differentiating thoracic malignant tumors, such as epithelioid malignant pleural mesothelioma (EMPM) and non-small-cell lung carcinoma (NSCLC), primarily comprising lung adenocarcinoma (LAC) and lung squamous cell carcinoma (LSCC), remains a challenge in routine pathological diagnosis. This study aimed to evaluate whether podoplanin (PDPN) immunohistochemistry combined with scanning electron microscopy (SEM) using the NanoSuit-correlative light and electron microscopy (CLEM) methods could serve as a reliable tool for distinguishing these thoracic malignancies. Methods/Results: Initially, PDPN expression was assessed by immunohistochemical analysis in 11 EMPM, 100 LAC, and 23 LSCC cases. PDPN positivity was predominantly observed in the cell membrane and was significantly more frequent in EMPM (100%) than in LAC (2%; p < 0.0001) or LSCC (43.5%; p = 0.0018). Subsequently, field emission–SEM (FE-SEM) observations of PDPN-positive sites on immunohistochemical slides, conducted using the NanoSuit-CLEM method, revealed distinctive ultrastructural features. EMPM exhibited densely packed, elongated microvilli, whereas such structures were absent in LAC and LSCC. Furthermore, analysis of thick-cut sections (20 μm) demonstrated extensive microvilli coverage characteristic of EMPM. Conclusions: These findings suggest that the combined approach of PDPN immunohistochemistry and FE-SEM observation of PDPN-positive sites, using the NanoSuit-CLEM method, constitutes an effective diagnostic strategy for enhancing the accuracy of distinguishing EMPM from NSCLCs. Full article

Background: Pancreatic ductal adenocarcinoma (PDAC), which has a poor prognosis, involves an overabundance of fibroblasts and extracellular matrix. Cancer-associated fibroblasts (CAFs) are critical for providing structural support by secreting soluble factors and extracellular matrix proteins into the stroma. We assessed the potential of near-infrared photoimmunotherapy (NIR-PIT) targeting CAFs in PDAC. Methods: PDAC cells (Capan-1 and SUIT-2) and CAFs (hPSC-5) were used. Anti-human fibroblast activation protein (FAP)/podoplanin (PDPN) antibodies were used to bind to CAFs and conjugates with the specific photosensitizer IRDye^®700DX (IR700) to investigate the effects of NIR-PIT. Thereafter, BALB/c Slc-nu/nu mice were transplanted with Capan-1 and/or CAFs and treated with gemcitabine (GEM) with or without NIR-PIT. Results: The binding rate of anti-FAP antibody-AlexaFluor^®488 conjugate to hPSC-5 cells was high, whereas that of the anti-PDPN antibody-conjugate was not. The incubation of anti-FAP antibody-IR700 conjugate (αFAP-IR700) with hPSC-5 cells for 3 h led to maximal fluorescence on the surface of hPSC-5 cells. When NIR-PIT with αFAP-IR700 was performed in the co-culture group of Capan-1 and hPSC-5 cells, the proliferative capacity of Capan-1 cells decreased to the same level as that when Capan-1 cells were cultured alone (p < 0.05). In vivo, compared with the GEM group, the NIR-PIT with the GEM group showed a significant reduction in the tumor volume (day 28: 79 vs. 382 mm³, p < 0.05). Tumor volumes in the NIR-PIT group were not reduced compared with those in the control group. Conclusions: Combining NIR-PIT with conventional chemotherapy to target CAFs may enhance the anticancer effects on PDAC. Full article

Inflammatory bowel disease (IBD), encompassing Crohn’s disease (CD), ulcerative colitis (UC), and IBD unclassified (IBD-U), is a complex intestinal disorder influenced by genetic, environmental, and microbial factors. Recent evidence highlights the gut microbiota as a pivotal biomarker and modulator in IBD pathogenesis. Dysbiosis, characterized by reduced microbial diversity and altered composition, is a hallmark of IBD. A consistent decrease in anti-inflammatory bacteria, such as Faecalibacterium prausnitzii, and an increase in pro-inflammatory species, including Escherichia coli, have been observed. Metabolomic studies reveal decreased short-chain fatty acids (SCFAs) and secondary bile acids, critical for gut homeostasis, alongside elevated pro-inflammatory metabolites. The gut microbiota interacts with host immune pathways, influencing morphogens, glycosylation, and podoplanin (PDPN) expression. The disruption of glycosylation impairs mucosal barriers, while aberrant PDPN activity exacerbates inflammation. Additionally, microbial alterations contribute to oxidative stress, further destabilizing intestinal barriers. These molecular and cellular disruptions underscore the role of the microbiome in IBD pathophysiology. Emerging therapeutic strategies, including probiotics, prebiotics, and dietary interventions, aim to restore microbial balance and mitigate inflammation. Advanced studies on microbiota-targeted therapies reveal their potential to reduce disease severity and improve patient outcomes. Nevertheless, further research is needed to elucidate the bidirectional interactions between the gut microbiome and host immune responses and to translate these insights into clinical applications. This review consolidates current findings on the gut microbiota’s role in IBD, emphasizing its diagnostic and therapeutic implications, and advocates for the continued exploration of microbiome-based interventions to combat this debilitating disease. Full article

Objective: We investigated morphological differences in osteocyte processes between aged mice and our original podoplanin-conditional knockout (cKO) mice in which the floxed exon 3 of podoplanin was deleted by Dmp-1-driven Cre (Dmp1-Cre;PdpnΔ/Δ). Methods: SEM observation on osteocyte cell process, histochemistry for bone remodeling with mechanostress, and RT-PCR for RANKL and M-CSF in podoplanin cKO mouse bone with mechanostress was investigated. Results: SEM observations showed fewer and thinner osteocyte processes in femurs from 23-week-old Dmp1-Cre;PdpnΔ/Δ mice than from 23-week-old wild-type mice, while the numbers of osteocyte processes in femurs and calvarias were similar in 23-week-old Dmp1-Cre;PdpnΔ/Δ mice and 48-week-old wild-type mice. Furthermore, cell process numbers in femurs and calvarias were significantly smaller in 23-week-old Dmp1-Cre;PdpnΔ/Δ mice than in 48-week-old wild-type mice. In the test for differences in alveolar bone resorption under mechanical stress between Dmp1-Cre;PdpnΔ/Δ and wild-type mice, the area of TRAP-positive resorption pits was larger in wild-type mice than in Dmp1-Cre;PdpnΔ/Δ mice. In a quantitative tissue PCR analysis, the mRNA expression levels of RANKL and M-CSF in alveolar bone under mechanical stress were significantly lower in Dmp1-Cre;PdpnΔ/Δ mice than in wild-type mice. These results suggest that a reduction in cell process formation in osteocytes with podoplanin cKO affected the absorption of alveolar bone under mechanical stress in Dmp1-Cre;PdpnΔ/Δ mice. Conclusions: In podoplanin-deficient bone, the deformation of osteocyte processes by mechanical stimuli is not recognized as a stress due to the lower number of cell processes with podoplanin deficiency; therefore, the production of osteoclast migration/differentiation factors by activated osteocytes is not fully induced and macrophage migration to alveolar bone with mechanical stress appeared to be suppressed. These results indicate that podoplanin-dependent osteocyte process formation indirectly plays a key role in sensing mechanical stress in bone. Full article

Membrane proteins, especially extracellular domains, are key therapeutic targets due to their role in cell communication and associations. Yet, their functions and interactions often remain unclear. This study presents a general method to discover interactions of membrane proteins with immune cells and subsequently to deorphanize their respective receptors. We developed a comprehensive recombinant protein library of extracellular domains of human transmembrane proteins and proteins found in the ER-Golgi-lysosomal systems. Using this library, we conducted a flow-cytometric screen that identified several cell surface binding events, including an interaction between carbonic anhydrase 9 (CAH9/CA9/CAIX) and CD14^high cells. Further analysis revealed this interaction was indirect and mediated via platelets bound to the monocytes. CA9, best known for its diverse roles in cancer, is a promising therapeutic target. We utilized our library to develop an AlphaLISA high-throughput screening assay, identifying CLEC2 as one robust CA9 binding partner. A five-amino-acid sequence (EDLPT) in CA9, identical to a CLEC2 binding domain in Podoplanin (PDPN), was found to be essential for this interaction. Like PDPN, CA9-induced CLEC2 signaling is mediated via Syk. A Hodgkin’s lymphoma cell line (HDLM-2) endogenously expressing CA9 can activate Syk-dependent CLEC2 signaling, providing enticing evidence for a novel function of CA9 in hematological cancers. In conclusion, we identified numerous interactions with monocytes and platelets and validated one, CA9, as an endogenous CLEC2 ligand. We provide a new list of other putative CA9 interaction partners and uncovered CA9-induced CLEC2 activation, providing new insights for CA9-based therapeutic strategies. Full article

Glioblastoma multiforme (GBM) is a malignant primary brain tumor categorized as a Grade 4 astrocytic glioma by the World Health Organization (WHO). Some of the established risk factors of GBM include inherited genetic syndromes, body mass index, alcohol consumption, use of non-steroidal anti-inflammatory drugs (NSAIDs), and therapeutic ionizing radiation. Vascular anomalies, including local and peripheral thrombosis, are common features of GBM. Podoplanin (PDPN), a ligand of the C-type lectin receptor (CLEC-2), promotes platelet activation, aggregation, venous thromboembolism (VTE), lymphatic vessel formation, and tumor metastasis in GBM patients. It is regulated by Prox1 and is expressed in developing and adult mammalian brains. It was initially identified on lymphatic endothelial cells (LECs) as the E11 antigen and on fibroblastic reticular cells (FRCs) of lymphoid organs and thymic epithelial cells as gp38. In recent research studies, its expression has been linked with prognosis in GBM. PDPN-expressing cancer cells are highly pernicious, with a mutant aptitude to form stem cells. Such cells, on colocalization to the surrounding tissues, transition from epithelial to mesenchymal cells, contributing to the malignant carcinogenesis of GBM. PDPN can be used as an independent prognostic factor in GBM, and this review provides strong preclinical and clinical evidence supporting these claims. Full article

Podoplanin (PDPN) overexpression is associated with poor clinical outcomes in various tumors. PDPN is involved in malignant tumor progression by promoting invasiveness and metastasis. Therefore, PDPN is considered a promising target of monoclonal antibody (mAb)-based therapy. Because PDPN also plays an essential role in normal cells such as kidney podocytes, cancer specificity is required to reduce adverse effects on normal cells. We developed a cancer-specific mAb (CasMab) against PDPN, PMab-117 (rat IgM, kappa), by immunizing rats with PDPN-overexpressed glioblastoma cells. The recombinant mouse IgG_2a-type PMab-117 (PMab-117-mG_2a) reacted with the PDPN-positive tumor PC-10 and LN319 cells but not with PDPN-knockout LN319 cells in flow cytometry. PMab-117-mG_2a did not react with normal kidney podocytes and normal epithelial cells from the lung bronchus, mammary gland, and corneal. In contrast, one of the non-CasMabs against PDPN, NZ-1, showed high reactivity to PDPN in both tumor and normal cells. Moreover, PMab-117-mG_2a exerted antibody-dependent cellular cytotoxicity in the presence of effector splenocytes. In the human tumor xenograft models, PMab-117-mG_2a exhibited potent antitumor effects. These results indicated that PMab-117-mG_2a could be applied to antibody-based therapy against PDPN-expressing human tumors while reducing the adverse effects. Full article

(Background) Cancer-associated fibroblasts (CAFs) are major cancer stromal components. CAFs have diverse functions and cell origins. Podoplanin (PDPN), a lymphatic vessel marker, is also a CAF marker in certain cancers. On daily diagnosis of early colorectal carcinoma (CRC), PDPN upregulation in the stroma is often encountered, suggesting PDPN-positive CAFs have emerged. However, PDPN-positive CAFs in early CRC have not been studied well. (Methods) On immunohistochemistry, PDPN expression in the lamina propria or stroma of adenomas, early CRCs, and neuroendocrine tumors, their normal neighbors, and non-neoplastic colorectal lesions were compared. Single-cell RNA sequencing (scRNA-seq) of CRC was used to explore PDPN^high CAFs’ cell origins. (Results) Reticular cells or pericryptal fibroblasts in the lamina propria of adenomas and early CRCs showed higher PDPN expression than did normal mucosae and non-neoplastic lesions (p < 0.01). Pericryptal PDPN expression was a diagnostic feature of adenomas and early CRCs. scRNA-seq of CRCs highlighted that PDPN^high CAFs had distinctly higher COL4A1, COL4A2, and WNT5A expression, unlike well-known CAFs characterized by high FAP, POSTN, or ACTA2 expression. (Conclusions) We demonstrated that pericryptal fibroblasts and reticular cells in the lamina propria are origins of early-stage CRC CAFs and thus have potential as a diagnostic marker for distinguishing colorectal non-neoplastic from neoplastic lesions. Full article

Tumor cell-induced platelet aggregation (TCIPA) is a mechanism for the protection of tumor cells in the bloodstream and the promotion of tumor progression and metastases. The platelet C-type lectin-like receptor 2 (CLEC-2) can bind podoplanin (PDPN) on a cancer cell surface to facilitate TCIPA. Selective blockage of PDPN-mediated platelet–tumor cell interaction is a plausible strategy for inhibiting metastases. In this study, we aimed to screen for aptamers, which are the single-stranded DNA oligonucleotides that form a specific three-dimensional structure, bind to specific molecular targets with high affinity and specificity, bind to PDPN, and interfere with PDPN/CLEC-2 interactions. The systematic evolution of ligands by exponential enrichment (SELEX) was employed to enrich aptamers that recognize PDPN. The initial characterization of ssDNA pools enriched by SELEX revealed a PDPN aptamer designated as A1 displaying parallel-type G-quadruplexes and long stem-and-loop structures and binding PDPN with a material with a dissociation constant (K_d) of 1.3 ± 1.2 nM. The A1 aptamer recognized both the native and denatured form of PDPN. Notably, the A1 aptamer was able to quantitatively detect PDPN proteins in Western blot analysis. The A1 aptamer could interfere with the interaction between PDPN and CLEC-2 and inhibit PDPN-induced platelet aggregation in a concentration-dependent manner. These findings indicated that the A1 aptamer is a candidate for the development of biosensors in detecting the levels of PDPN expression. The action by A1 aptamer could result in the prevention of tumor cell metastases, and if so, could become an effective pharmacological agent in treating cancer patients. Full article

In colorectal cancer (CRC), attempts to identify cancer cell-specific markers to guide antibody-mediated therapeutics have failed to uncover markers that are both exclusive to cancer tissues and abundant across CRCs. Alternatively, cancer-associated fibroblasts (CAFs), which are abundant in the tumor microenvironment and upregulate unique surface markers, are not found in healthy tissues. Here, we evaluated the expression patterns of CAF-associated proteins α-smooth muscle actin (αSMA), fibroblast activation protein (FAP), podoplanin (PDPN), matrix metalloproteinase-2 (MMP2), transgelin (TAGLN), and THY1. While αSMA and THY1 were abundant in cancer tissues, high abundance in normal tissues limited their targeting potential. FAP was present in 94.5% of primary and metastatic CRC tissues and absent in 93.7% of adjacent normal colon and liver tissues assessed. These results indicate that FAP is a promising target for antibody conjugates with potential for broad application in CRC. Co-expression analyses showed that CRCs simultaneously expressing high levels of PDPN, MMP2, and THY1 were enriched for immune-related signatures, indicating potential for antibody-mediated immune engagers. Overall, this work highlights the potential of CAF proteins to act as therapeutic targets for novel anticancer agents and become important therapeutic biomarkers. Full article