Multilayered proteomics reveals that JAM-A promotes breast cancer progression via regulation of amino acid transporter LAT1.

Recent studies have shown that transmembrane-type tight junction proteins are upregulated in various cancers compared with their levels in normal tissues and are involved in cancer progression, suggesting that they are potential therapeutic targets. Here, we demonstrated the expression profile and a novel role of junctional adhesion molecule-A (JAM-A) in breast cancer. Immunohistochemistry of surgical specimens showed that JAM-A was highly expressed from carcinoma in situ lesions, as in other adenocarcinomas, with higher expression in invasive carcinomas. High expression of JAM-A contributed to malignant aspects such as lymph node metastasis and lymphatic involvement positivity. In breast cancer cells, JAM-A expression status affects malignant potentials including proliferation and migration. Multilayered proteomics revealed that JAM-A interacts with the amino acid transporter LAT1 in breast cancer cells. JAM-A regulates the expression of LAT1 and interacts with it on the whole cell membrane, leading to enhanced amino acid uptake to promote tumor growth. Double high expression of JAM-A and LAT1 predicts poor prognosis in patients with breast cancer. Of note, an antibody against an extracellular domain of JAM-A suppressed the proliferation of breast cancer cells. Our findings indicate the possibility of JAM-A-targeted therapy ideally combined with LAT1-targeted therapy as a new therapeutic strategy against breast cancer.

Vitamin D-metabolizing enzyme CYP24A1 affects oncogenic behaviors of oral squamous cell carcinoma and its prognostic implication.

Vitamin D is an essential molecule for cellular homeostasis, playing a critical role in cell fate decisions including cell proliferation, differentiation, and viability. Accumulating evidence has revealed that expression of the vitamin D-metabolizing enzyme CYP24A1 is dysregulated in different types of human malignancy. CYP24A1 has been shown to be involved in the oncogenic property of a variety of carcinoma cells. However, the pathological relevance of CYP24A1 expression level in human oral malignancy remains to be clarified. In the present study, suppression of CYP24A1 expression in oral squamous cell carcinoma (OSCC) cells increased cell proliferation, invasive activity, colony formation efficacy, and tumor growth in vivo. In addition, knockout of CYP24A1 expression inhibited cell death induced by two different types of anticancer drugs, i.e., fluorouracil and cisplatin. Gene clustering by RNA-sequence analysis revealed that several signaling molecules associated with MYC are involved in CYP24A1-mediated oncogenic behaviors. Furthermore, decreased expression level of CYP24A1 was observed in 124/204 cases (61%) of OSCC and was shown to be associated with short relapse-free and overall survival periods. The results showed that a low expression level of CYP24A1 promotes the oncogenic activity of OSCC and is significantly associated with poor prognosis in patients with this malignancy.

A novel approach to diagnosing crystal-storing histiocytosis: utility of scanning electron microscopy for formalin-fixed paraffin-embedded tissue specimens.

Crystal-storing histiocytosis (CSH) is a rare disorder that shows infiltration of histiocytes with an aberrant cytoplasmic accumulation of crystalline structures and is often accompanied by lymphoproliferative-plasma cell disorders (LP-PCD) as background diseases. The diagnosis of CSH requires identification of crystalline structures that accumulate in the infiltrating histiocytes, which may be challenging by optical microscopy alone. In this case report, we describe an atypical course of systemic CSH with multifocal fibrosclerosis of an unknown background disease that was diagnosed by ultrastructural observation, including transmission electron microscopy (TEM) and scanning electron microscopy (SEM), in pathological autopsy. In addition, crystalline structures were successfully identified by scanning electron microscopic observations using formalin-fixed and paraffin-embedded (FFPE) tissue from biopsy specimens taken before death. Since CSH was identified by SEM in a tiny biopsy specimen, observation of histiocytic infiltrative lesions by SEM using FFPE tissue may lead to early detection of and initiation of treatment for CSH.

Elevated expression of endocan in the development of cervical squamous neoplasia of the uterus.

Accumulated evidence has shown that endocan, which was originally called endothelial cell-specific molecule-1, is an attractive prognostic factor in a variety of cancers. However, the relevance of endocan expression in human malignancies remains to be clarified. In the present study, the expression of endocan in cervical squamous neoplasia of the uterus, including low- and high-grade squamous intraepithelial lesions (LSIL and HSIL, respectively), as well as in invasive squamous cell carcinoma was examined by immunohistochemistry. Endocan was not sufficiently expressed in the normal cervical epithelium. Endocan expression was present in LSIL cases but was limited to basal and parabasal areas of the cells. HSIL cases exhibited strong expression of endocan with widely distributed expression toward the epithelial surface. In contrast, further strong expression of endocan was not observed in patients with invasive carcinoma. This study is the first study showing increased expression of endocan in precancerous dysplastic lesions and malignancy of the cervix. The data suggest that a high expression level of endocan potentially contributes to the development of cervical squamous neoplasia of the uterus.

Suppression of the vitamin D metabolizing enzyme CYP24A1 provides increased sensitivity to chemotherapeutic drugs in breast cancer.

Vitamin D is an essential nutrient for the human body not only for the metabolism of calcium but also for homeostasis. Vitamin D contributes to cell fate decisions, including cell proliferation, differentiation and viability. Accumulated epidemiological data suggest a relationship between vitamin D deficiency and carcinogenesis in numerous organs. Furthermore, it is known that the expression of the vitamin D metabolizing enzyme, cytochrome P450 family 24 subtype A1 (CYP24A1), is increased in different types of human malignancy including breast carcinoma. However, the pathological relevance of elevated CYP24A1 expression level requires further clarification. In the present study, it was demonstrated that CYP24A1 promoted the oncogenic property of breast carcinoma cells. Consistent with previous reports, it was demonstrated that the expression of CYP24A1 was elevated in invasive breast carcinoma and significantly decreased the overall survival of patients with invasive breast carcinoma. Importantly, suppression of CYP24A1 expression significantly enhanced cell death sensitivity to two anticancer drugs with pharmacologically different modes of action, cisplatin and gefitinib. The results of the present study suggest the possibility of CYP24A1­inhibiting therapy as a novel therapy in breast cancer with overexpression of CYP24A1.

Vitamin D metabolism in cancer: potential feasibility of vitamin D metabolism blocking therapy.

In this review, we discuss the possibility of the vitamin D metabolizing enzyme CYP24A1 being a therapeutic target for various tumors including breast, colorectal and prostate tumors. Given the pleiotropic cellular activity of vitamin D, its deficiency impairs its physiological function in target cells and results in various pathologies including cancer. In addition, accumulated data have shown that elevated expression of CYP24A1 promotes carcinogenesis in various cancer subtypes by decreasing the bioavailability of vitamin D metabolites. Thus, we propose the potential feasibility of vitamin D metabolism-blocking therapy in various types of human malignancies that express constitutive CYP24A1.

Retinoic acid metabolism in cancer: potential feasibility of retinoic acid metabolism blocking therapy.

Retinoic acid (RA) is an active metabolite of vitamin A, which is an essential signaling molecule involved in cell fate decisions, such as differentiation, proliferation, and apoptosis, in a wide variety of cell types. Accumulated data have demonstrated that expression of RA-metabolizing enzymes, CYP26A1, B1, and C1 (cytochrome P450, family 26A1, B1, and C1, respectively), protects cells and tissues from exposure to RA through restriction of RA access to transcriptional machinery by converting RA to rapidly excreted derivatives. CYP26 enzymes play similar but separate roles in limiting the consequences of fluctuations in nutritional vitamin A. Recently, we found that RA depletion caused by expression of CYP26A1 promotes malignant behaviors of tumor cells derived from various tissues, implicating CYP26A1 as a candidate oncogene. We also showed that the expression levels of CYP26 enzymes are elevated in various types of cancer. We have provided evidence for oncogenic and cell survival properties of CYP26 enzymes, indicating that these molecules are possible therapeutic targets for CYP26-expressing malignancies.

Simultaneous Pseudoprogression and an Immune-related Adverse Event of Pulmonary Pleomorphic Carcinoma after Combined Therapy with Cytotoxic Anticancer Agents and Immune Checkpoint Inhibitor.

Pulmonary pleomorphic carcinoma is rare among lung tumors. Pulmonary pleomorphic carcinoma is resistant to chemotherapy. However, treatment with taxane anticancer agents and immune checkpoint inhibitors has been reported to be effective. When using immune checkpoint inhibitors, pseudoprogression and true progression are difficult to distinguish, and immune-related adverse events (irAEs) are common. We herein report a patient with simultaneous pseudoprogression and irAEs after combined therapy with cytotoxic agents and an immune checkpoint inhibitor for pulmonary pleomorphic carcinoma. Immune checkpoint inhibitors are effective against pulmonary pleomorphic carcinoma, but patients should be monitored for pseudoprogression and irAEs.

Claudin-18.2 as a therapeutic target in cancers: cumulative findings from basic research and clinical trials.

Claudins are major components of tight junctions that maintain cell polarity and intercellular adhesion. The dynamics of claudins in cancer cells have attracted attention as a therapeutic target. During carcinogenesis, claudin expression is generally downregulated; however, overexpression of claudin-18.2 has been observed in several types of cancers. Upregulated and mislocalized claudin-18.2 expression in cancer cells has been suggested as a therapeutic target. Research on claudin-18.2 has revealed its involvement in carcinogenesis. Clinical trials using zolbetuximab, a monoclonal antibody targeting claudin-18.2, for patients with advanced cancer yielded positive results with few high-grade adverse events; thus, it is expected to be a novel and effective therapeutic. Here, we review current insights into the role that claudin-18.2 plays in basic cancer research and clinical applications. A better understanding of these roles will facilitate the development of new treatment strategies for cancer patients with poor prognoses.

Regulatory roles of claudin-1 in cell adhesion and microvilli formation.

Aberrant expression of tight junction proteins has recently been focused on in the cancer research field. We previously showed that claudin-1 is aberrantly expressed from an early stage of uterine cervical adenocarcinoma and contributes to malignant potentials. To elucidate the molecular mechanisms underlying tumor-promoting roles of claudin-1, we established and analyzed claudin-1 knockout cells. Knockout of claudin-1 suppressed conventional tight junctional functions, barrier and fence functions, and expression of cell adhesion-associated proteins including E-cadherin. Comparative proteome analysis revealed that expression of claudin-1 affected expression of a wide range of proteins, especially proteins that are associated with cell adhesion and actin cytoskeleton remodeling. Interactome analysis of the identified proteins revealed that E-cadherin and focal adhesion kinase play central roles in the claudin-1-dependently affected protein network. Moreover, knockout of claudin-1 significantly suppressed microvilli formation and activity of Ezrin/Radixin/Moesin. Taken together, the results indicate that expression of claudin-1 affects not only conventional tight junction function but also expression and activity of a wide range of proteins, especially proteins that are associated with cell adhesion and actin cytoskeleton remodeling, to contribute to malignant potentials and microvilli formation in cervical adenocarcinoma cells.

A systemic apolipoprotein A-IV-associated amyloidosis confirmed by proteome analysis.

Amyloidosis is induced by extracellular deposition of certain proteins. Thirty-six proteins have so far been identified as amyloidogenic proteins in humans. Although it is very important to determine the specific amyloid protein type for the choice of therapy for amyloidosis patient, it might be difficult to identify specific proteins from amyloid-deposited tissue. Apolipoprotein A-IV is known as an amyloid-associated protein, but there have been few reports of apolipoprotein A-IV amyloidosis. Here we report a case of systemic apolipoprotein A-IV-associated amyloidosis that was confirmed by proteome analysis using formalin-fixed paraffin-embedded tissue and an immunohistochemical technique.

Aberrant expression of junctional adhesion molecule-A contributes to the malignancy of cervical adenocarcinoma by interaction with poliovirus receptor/CD155.

Recent studies have shown that aberrant expression of tight junction proteins (TJP) contributes to malignant potential of various cancers. In the present study, we investigated the expression of junctional adhesion molecule-A (JAM-A), one of the transmembrane TJP, in uterine cervical adenocarcinoma and the significance of its expression for malignancy. Immunohistochemistry on human surgical specimens showed that JAM-A was aberrantly expressed in neoplastic regions including adenocarcinoma in situ (AIS). Knockout of JAM-A significantly suppressed cell proliferation and colony-forming and migration abilities. We also showed that an antibody specific to an extracellular region of JAM-A reduced cell proliferation ability and that loss of JAM-A increased drug sensitivity of cervical adenocarcinoma cells. Based on a comprehensive proteome analysis, we found that poliovirus receptor (PVR/CD155) was regulated by JAM-A and formed a physical interaction with JAM-A. In human surgical specimens, PVR/CD155 expression was significantly correlated with some clinicopathological features and prognosis of cervical adenocarcinoma. Interestingly, most of the PVR/CD155-positive cases expressed a high level of JAM-A, and patients with the expression pattern of PVR/CD155 positive/JAM-A high had significantly shorter periods of relapse-free survival (P = .00964) and overall survival (P = .0204) than those for the other patients. Our observations suggest that aberrant expression of JAM-A promotes malignancy of uterine cervical adenocarcinoma by regulation of PVR/CD155, and JAM-A is therefore a potential therapeutic target for this malignancy.

Aldolase A promotes epithelial-mesenchymal transition to increase malignant potentials of cervical adenocarcinoma.

Recent studies have revealed that metabolic reprogramming is closely associated with epithelial-mesenchymal transition (EMT) during cancer progression. Aldolase A (ALDOA) is a key glycolytic enzyme that is highly expressed in several types of cancer. In this study, we found that ALDOA is highly expressed in uterine cervical adenocarcinoma and that high ALDOA expression promotes EMT to increase malignant potentials, such as metastasis and invasiveness, in cervical adenocarcinoma cells. In human surgical specimens, ALDOA was highly expressed in cervical adenocarcinoma and high ALDOA expression was correlated with lymph node metastasis, lymphovascular infiltration, and short overall survival. Suppression of ALDOA expression significantly reduced cell growth, migration, and invasiveness of cervical cancer cells. Aldolase A expression was partially regulated by hypoxia-inducible factor-1α (HIF-1α). Shotgun proteome analysis revealed that cell-cell adhesion-related proteins were significantly increased in ALDOA-overexpressing cells. Interestingly, overexpression of ALDOA caused severe morphological changes, including a cuboidal-to-spindle shape shift and reduced microvilli formation, coincident with modulation of the expression of typical EMT-related proteins. Overexpression of ALDOA increased migration and invasion in vitro. Furthermore, overexpression of ALDOA induced HIF-1α, suggesting a positive feedback loop between ALDOA and HIF-1α. In conclusion, ALDOA is overexpressed in cervical adenocarcinoma and contributes to malignant potentials of tumor cells through modulation of HIF-1α signaling. The feedback loop between ALDOA and HIF-1α could become a therapeutic target to improve the prognosis of this malignancy.

Elevated expression of G protein-coupled receptor 30 (GPR30) is associated with poor prognosis in patients with uterine cervical adenocarcinoma.

Uterine cervical adenocarcinoma has a worse prognosis than that of squamous cell carcinoma and useful diagnostic and prognostic markers are needed. Estrogen is one of the key regulators of several cancers, however, the estrogen signaling has not been focused on in cervical adenocarcinoma. Here, we shows expression profile of classical estrogen receptor (ER) and a novel membrane type estrogen receptor, G protein-coupled receptor 30 (GPR30), in surgical specimens (n=53). GPR30 was strongly expressed on the cell membrane and in the cytoplasm in adenocarcinoma in situ (AIS) and adenocarcinoma, and its expression was especially strong at the invasion front in most of the cases of GPR30-positive adenocarcinoma. Nuclear staining of ER was strong in non-neoplastic glands, whereas it was almost absent in most of the AIS and adenocarcinoma cases. There was a weak but statistically significant negative correlation between immunoreactivity of GPR30 and that of ER in cervical AIS and adenocarcinoma lesions (Spearman's correlation, r=-0.324, p=0.017). ROC curve analysis revealed that immunoreactivity of GPR30 successfully distinguished neoplasms from non-neoplastic glands with high specificity (100%) and sensitivity (75.5%). GPR30 positivity was significantly correlated with histological type (p=0.009), tumor diameter (p=0.003), tumor size (p<0.001), lymphovascular infiltration (p=0.005) and UICC stage (p<0.001). ER expression was correlated only with tumor factor (p=0.047). GPR30-high patients had poor prognosis with a significantly shorter overall survival (OS) period (p=0.0309). GPR30 expression is a potential diagnostic and prognostic marker.

Elevated expression of JAM-A promotes neoplastic properties of lung adenocarcinoma.

A cell-cell adhesion protein, junctional adhesion molecule-A (JAM-A), has been shown to be involved in neoplasia of various organs. However, the fundamental role of JAM-A in tumorigenesis is still under debate because dysregulated expression of this protein has distinct effects, playing opposite roles in carcinogenesis depending on the target tissues. In the present study, we found elevated levels of JAM-A expression in lung adenocarcinoma and its preinvasive lesions, including atypical adenomatous hyperplasia and adenocarcinoma in situ by immunohistochemistry. We also showed that suppression of constitutive JAM-A expression conferred target cells with increased susceptibility to apoptosis in lung adenocarcinoma cells. Consequently, inhibition of JAM-A activity decreased colony-forming capability in vitro and tumorigenicity in vivo. The transformed phenotype following suppression of JAM-A expression was sufficient to reduce motile and invasive capacities. Importantly, knockout of JAM-A had striking effects on cells. Our observations suggest that increased expression of JAM-A promotes neoplasia of lung adenocarcinoma. In addition, an anti-JAM-A antibody efficiently reduced cell proliferation and provoked apoptosis, indicating the potential feasibility of JAM-A-inhibitory cancer therapy.