Clinicopathological Significance and Prognostic Role of High Mobility Group Box 1 (HMGB1), Toll-Like Receptor (TLR) 2 and TLR4 in Breast Cancer

High-mobility group box 1 (HMGB1) functions as damage-associated molecular pattern (DAMPs), released into extracellular space during cellular stress. Extracellular HMGB1 act as signal molecules through Toll-like receptor (TLR) 2 or TLR4, exerting diverse functions in both normal cells and malignant cells including breast cancer. However, their comprehensive examination in breast cancer tissues is lacking. Thus, we immunolocalized them in 112 breast cancer tissues, correlating their immunoreactivity with clinicopathological parameters and clinical outcomes to clarify their significance in breast cancer. We demonstrated that nuclear HMGB1 immunoreactivity was correlated with tumor progression and longer disease-free survival. In contrast, TLR2 immunoreactivity was correlated with increased cell proliferation and shorter disease-free survival, dependent on cytoplasmic HMGB1 immunoreactivity. Additionally, TLR4 immunoreactivity correlated with chemoresistance, regardless of cytoplasmic HMGB1 immunoreactivity. It was therefore considered that TLR2 collaboratively contributed to breast cancer progression with HMGB1-DAMPs to become a worse prognostic factor. Meanwhile, TLR4 served as a worse prognostic factor associated with chemoresistance, irrespective of HMGB1.

Morphometric analysis of nuclear shape irregularity as a novel predictor of programmed death-ligand 1 expression in lung squamous cell carcinoma

Immune checkpoint inhibitor (ICI) therapy has been established as one of the key treatment strategies for lung squamous cell carcinoma (LUSQ). The status of programmed death-ligand 1 (PD-L1) in tumor cells and/or immune cells using immunohistochemistry has been primarily used as a surrogate marker for determining ICI treatment; however, when the tissues to be examined are small, false-negative results could be unavoidable due to the heterogeneity of PD-L1 immunoreactivity. To overcome this practical limitation, we attempted to explore the status of nuclear atypia evaluated using morphometry as a potential predictor of PD-L1 status in LUSQ. We correlated the parameters related to nuclear atypia with PD-L1 status using two different cohorts of LUSQ patients (95 cases from The Cancer Genome Atlas database and 30 cases from the Miyagi Cancer Center). Furthermore, we studied the gene mutation status to elucidate the genetic profile of PD-L1 predictable cases. The results revealed that nuclear atypia, especially morphometric parameters related to nuclear shape irregularity, including aspect ratio, circularity, roundness, and solidity, were all significantly associated with PD-L1 status. Additionally, LUSQ cases with high PD-L1 expression and pronounced nuclear atypia were significantly associated with C10orf71 and COL14A1 mutations compared with those with low PD-L1 expression and mild nuclear atypia. We demonstrated for the first time that nuclear shape irregularity could represent a novel predictor of PD-L1 expression in LUSQ. Including the morphometric parameters related to nuclear atypia in conjunction with PD-L1 status could help determine an effective ICI therapeutic strategy; however, further investigation is required.

Progesterone receptor-Grb2 interaction is associated with better outcomes in breast cancer

In addition to mediating nuclear transcription, PR mediates extranuclear functions mainly through the PR polyproline domain (PPD) interaction with the SH3 domain of cytoplasmic signaling molecules. PR-PPD-SH3 interaction inhibits EGF-mediated signaling and decreases lung cancer cell proliferation. Grb2 is an essential adaptor molecule with an SH2 domain flanked by two SH3 domains. In this study, we examined whether PR, through interaction between PR-PPD and Grb2-SH3, can interact with Grb2 in cells and breast cancer tissues. Our previous study shows that interaction between PR-PPD and Grb2 could interfere with cytoplasmic signaling and lead to inhibition of EGF-mediated signaling. GST-pulldown analysis shows that PR-PPD specifically interacts with the SH3 domains of Grb2. Immunofluorescence staining shows colocalization of PR and Grb2 in both the nucleus and cytoplasm in BT-474 breast cancer cells. Using Bimolecular Fluorescence Complementation (BiFC) analysis, we show that PR and Grb2 interact in breast cancer cells through the Grb2-SH3 domain. Proximity Ligation Assay (PLA) analysis of 43 breast cancer specimens shows that PR-Grb2 interaction is associated with low histological stage and negatively correlates with lymph node invasion and metastasis in breast cancer. These results, together with our previous findings, suggest that PR-PPD interaction with Grb2 plays an essential role in PR-mediated growth factor signaling inhibition and could contribute significantly to better prognosis in PR- and Grb2-positive breast cancer. Our finding provides a basis for additional studies to explore a novel therapeutic strategy for cancer treatment.

Pronecroptotic Therapy Using Ceramide Nanoliposomes Is Effective for Triple-Negative Breast Cancer Cells

Regulated necrosis, termed necroptosis, represents a potential therapeutic target for refractory cancer. Ceramide nanoliposomes (CNLs), considered potential chemotherapeutic agents, induce necroptosis by targeting the activating protein mixed lineage kinase domain-like protein (MLKL). In the present study, we examined the potential of pronecroptotic therapy using CNLs for refractory triple-negative breast cancer (TNBC), for which there is a lack of definite and effective therapeutic targets among the various immunohistological subtypes of breast cancer. MLKL mRNA expression in tumor tissues was significantly higher in TNBC patients than in those with non-TNBC subtypes. Similarly, among the 50 breast cancer cell lines examined, MLKL expression was higher in TNBC-classified cell lines. TNBC cell lines were more susceptible to the therapeutic effects of CNLs than the non-TNBC subtypes of breast cancer cell lines. In TNBC-classified MDA-MB-231 cells, the knockdown of MLKL suppressed cell death induced by CNLs or the active substance short-chain C6-ceramide. Accordingly, TNBC cells were prone to CNL-evoked necroptotic cell death. These results will contribute to the development of CNL-based pronecroptotic therapy for TNBC.

Intratumoral cortisol associated with aromatase in the endometrial cancer microenvironment

Glucocorticoids bind to glucocorticoid receptors (GR). In the peripheral tissues, active cortisol is produced from inactive cortisone by 11β-hydroxysteroid dehydrogenase (HSD)1. 11β-HSD2 is responsible for this reverse catalysis. Although GR and 11β-HSDs have been reported to be involved in the malignant behavior of various cancer types, the concentration of glucocorticoids in cancer tissues has not been investigated. In this study, we measured glucocorticoids in serum and cancer tissues using liquid chromatography-tandem mass spectrometry and clarified, for the first time, the intratumoral "intracrine" production of cortisol by 11β-HSD1/2 in endometrial cancer. Intratumoral cortisol levels were high in the high-malignancy type and the cancer proliferation marker Ki-67-high group, suggesting that cortisol greatly contributes to the malignant behavior of endometrial cancer. A low expression level of the metabolizing enzyme 11β-HSD2 is more important than a high expression level of the synthase 11β-HSD1 for intratumoral cortisol action. Intratumoral cortisol was positively related to the expression/activity of estrogen synthase aromatase, which involved GR expressed in fibroblastic stromal cells but not in cancer cells. Blockade of GR signaling by hormone therapy is expected to benefit patients with endometrial cancer.

SGLT1 as an adverse prognostic factor in invasive ductal carcinoma of the breast

PURPOSE

Sodium/glucose cotransporter (SGLT) 1 and 2 expression in carcinoma cells was recently examined, but their association with the clinicopathological factors of the patients and their biological effects on breast carcinoma cells have remained remain virtually unknown. Therefore, in this study, we explored the expression status of SGLT1 and SGLT2 in breast cancer patients and examined the effects of SGLT1 inhibitors on breast carcinoma cells in vitro.

METHODS

SGLT1 and SGLT2 were immunolocalized and we first correlated the findings with clinicopathological factors of the patients. We then administered mizagliflozin and KGA-2727, SGLT1 specific inhibitors to MCF-7 and MDA-MB-468 breast carcinoma cell lines, and their growth-inhibitory effects were examined. Protein arrays were then used to further explore their effects on the growth factors.

RESULTS

The SGLT1 high group had significantly worse clinical outcome including both overall survival and disease-free survival than low group. SGLT2 status was not significantly correlated with clinical outcome of the patients. Both mizagliflozin and KGA-2727 inhibited the growth of breast cancer cell lines. Of particular interest, mizagliflozin inhibited the proliferation of MCF-7 cells, even under very low glucose conditions. Mizagliflozin downregulated vascular endothelial growth factor receptor 2 phosphorylation.

CONCLUSION

High SGLT1 expression turned out as an adverse clinical prognostic factor in breast cancer patient. This is the first study demonstrating that SGLT1 inhibitors suppressed breast carcinoma cell proliferation. These results indicated that SGLT1 inhibitors could be used as therapeutic agents for breast cancer patients with aggressive biological behaviors.

Interleukin (IL)-17A in triple-negative breast cancer: a potent prognostic factor associated with intratumoral neutrophil infiltration

BACKGROUND

Triple-negative breast cancer (TNBC) is characterized as highly immunogenic and lacks specific targeted therapies. Interleukin 17A (IL-17A) is a controversial cytokine and is known to have anti-tumor and pro-tumor roles depending on the tumor microenvironment. In addition, IL-17A has been recently implicated in the recruitments of neutrophil into tumor tissues. Although IL-17A is considered tumor-promoting in breast cancer, its significance in the possible regulation of neutrophil infiltration in TNBC is not clearly defined.

MATERIALS AND METHODS

We immunolocalized IL-17A, CD66b (neutrophil marker), and chemokine (C-X-C motif) ligand 1 (CXCL1, neutrophil chemoattractant) in 108 TNBC specimens and assessed their correlation among each other. The correlation between these markers and clinicopathological parameters was also assessed. We subsequently performed in vitro study to address the possible regulation of CXCL1 by IL-17A using TNBC cell lines, MDA-MB-231 and HCC-38.

RESULTS

It was revealed that IL-17A correlated significantly with CXCL1 and CD66b, also CD66b with CXCL1. Furthermore, IL-17A was significantly associated with shorter disease-free and overall survival, especially in a high density CD66b group of patients. In vitro results revealed that IL-17A upregulated CXCL1 mRNA expression in a dose and time dependent manner, and this induction was significantly suppressed by an Akt inhibitor.

CONCLUSION

IL-17A was considered to contribute to neutrophil infiltration by inducing CXCL1 in TNBC tissues and educating neutrophils to promote tumor progression. IL-17A might therefore serve as a potent prognostic factor in TNBC.

Immunolocalization of Cytoplasmic ER in ER-negative Breast Carcinoma as a Potent Favorable Prognostic Predictor

It is known that estrogen receptor (ER) has extranuclear signaling functions in addition to classical genomic pathway, and estrogenic actions have been reported in ER-negative breast carcinoma cells. However, significance of cytoplasmic-ER immunoreactivity has not been reported in ER-negative breast carcinoma tissues. We immunolocalized cytoplasmic ER in 155 ER-negative breast carcinoma tissues and evaluated its clinicopathological significance including the prognosis. As a comparative cohort set, we also used 142 ER-positive breast carcinomas. Cytoplasmic-ER immunoreactivity was detected in the carcinoma cells, but not in the non-neoplastic mammary epithelium. Cytoplasmic-ER immunoreactivity was positive in the 35 out of 155 (23%) ER-negative breast carcinoma cases, whereas it was detected only in 2 out of 142 (1.4%) ER-positive cases. Cytoplasmic ER status was positively associated with cytoplasmic-PR status, but inversely associated with Ki67 labeling index or distant free-relapse survival rate. Moreover, cytoplasmic-ER status turned out to be an independent good prognostic factor for both distant relapse-free survival and breast cancer specific survival. These findings suggested that cytoplasmic ER plays important roles in the ER-negative breast carcinoma, and cytoplasmic ER is a potent good prognostic factor. Among the ER-negative breast cancer patients, clinical benefit of chemotherapy may be limited in the cytoplasmic-ER positive cases.

New Perspectives on Sex Steroid Hormones Signaling in Cancer-Associated Fibroblasts of Non-Small Cell Lung Cancer

The importance of sex hormones, especially estrogen, in the pathogenesis of non-small-cell lung cancer (NSCLC) has attracted attention due to its high incidence among young adults and nonsmokers, especially those who are female. Cancer-associated fibroblasts (CAFs) reside in the cancer stroma and influence cancer growth, invasion, metastasis, and acquisition of drug resistance through interactions with cancer cells and other microenvironmental components. Hormone-mediated cell-cell interactions are classic cell-cell interactions and well-known phenomena in breast cancer and prostate cancer CAFs. In cancers of other organs, including NSCLC, the effects of CAFs on hormone-receptor expression and hormone production in cancer tissues have been reported; however, there are few such studies. Many more studies have been performed on breast and prostate cancers. Recent advances in technology, particularly single-cell analysis techniques, have led to significant advances in the classification and function of CAFs. However, the importance of sex hormones in cell-cell interactions of CAFs in NSCLC remains unclear. This review summarizes reports on CAFs in NSCLC and sex hormones in cancer and immune cells surrounding CAFs. Furthermore, we discuss the prospects of sex-hormone research involving CAFs in NSCLC.

PRB inhibited cell proliferation through let-7b-E2F1 in breast cancer

The presence of progesterone receptor (PR) and PR isoform B (PRB) in breast cancer is generally correlated with better clinical outcomes. Additionally, the significance of hormone-independent effects of PR/PRB correlated with better prognosis has been reported in non-small cell lung cancer (NSCLC). However, the detailed mechanism of that still remains unclear. In this study, we examined how microRNAs (miRNAs) could contribute to tumor inhibition via PR/PRB expression, in order to find miRNAs that have tumor-agnostic effects between breast cancer and NSCLC. We obtained miRNA data using human tissues of breast cancer and NSCLC from The Cancer Genome Atlas (TCGA) database and PCR array from NSCLC patients of our cohort. Subsequently, we examined the function of the miRNA through in vitro study using breast cancer cell lines. As a result, only let-7b expression was significantly correlated with PR expression in both cancers. Additionally, the expression of let-7b significantly inhibited cell proliferation by inducing PR and PRB expression in breast cancer cell lines. However, the positive correlation of let-7b and PRB required a mediated factor, E2 promoter binding factor 1 (E2F1), obtained from TCGA database analysis. In vitro experiments showed that let-7b significantly inhibited E2F1, and E2F1 significantly inhibited PRB. This study revealed that PRB inhibits the proliferation of breast cancer cells by the let-7b-E2F1 interaction. In addition, the immunohistochemical analysis in NSCLC was also consistent with these in vitro data. Our results could contribute to developing novel therapeutic strategies for patients with PR/PRB-positive cancer by targeting let-7b or PRB expression in breast cancer and possibly NSCLC.

Hormone-Dependent Cancers: New Aspects on Biochemistry and Molecular Pathology

Hormones, especially steroids, are closely involved in the physiological functions and proliferation of various target tissues and have long been known to play a key role in the tumorigenesis or carcinogenesis of these target tissues [...].

Induction of SGK1 via glucocorticoid-influenced clinical outcome of triple-negative breast cancer patients

PURPOSE

Triple-negative breast cancer (TNBC) is a highly heterogeneous and aggressive breast malignancy. Glucocorticoid (GC)-glucocorticoid receptor (GR) pathway plays a pivotal role in the cellular responses to various stresses including chemotherapy. Serum- and glucocorticoid-induced kinase-1 (SGK1) is known as an important downstream effector molecule in the GR signaling pathway, we attempted to explore its clinicopathological and functional significance in TNBC in which GR is expressed.

METHODS

We first immunolocalized GR and SGK1 and correlated the results with clinicopathological variables and clinical outcome in 131 TNBC patients. We also evaluated the effects of SGK1 on the cell proliferation and migration in TNBC cell lines with administration of dexamethasone (DEX) to further clarify the significance of SGK1.

RESULTS

The status of SGK1 in carcinoma cells was significantly associated with adverse clinical outcome in TNBC patients examined and was significantly associated with lymph node metastasis, pathological stage, and lymphatic invasion of the patients. In particular, SGK1 immunoreactivity was significantly associated with an increased risk of recurrence in GR-positive TNBC patients. Subsequent in vitro studies also demonstrated that DEX promoted TNBC cell migration and the silencing of gene expression did inhibit the cell proliferation and migration of TNBC cells under DEX treatment.

CONCLUSIONS

To the best of our knowledge, this is the first study to explore an association between SGK1 and clinicopathological variables and clinical outcome of TNBC patients. SGK1 status was significantly positively correlated with adverse clinical outcome of TNBC patients and promoted carcinoma cell proliferation and migration of carcinoma cells.

Kallikrein-Related Peptidase 12 (KLK12) in Breast Cancer as a Favorable Prognostic Marker

Kallikrein-related peptides (KLKs) form an evolutionally conserved subgroup of secreted serine proteases that consists of 15 members (KLK1-15). Previous studies have shown that KLKs regulate diverse biological processes, but the clinical significance of KLKs remains largely unclear in human breast cancers. We examined the expression profile of 15 KLK genes in breast carcinomas using microarray data. Next, we immunolocalized KLK12 in 140 breast carcinomas and evaluated its clinical significance. Subsequently, we examined the effects of KLK12 on proliferation and migration in breast cancer cell lines. From microarray analyses, it turned out that KLK12 was the most strongly associated with low-grade malignancy in breast carcinomas among the 15 KLK members. Immunohistochemical KLK12 status was positively associated with ER and PR status, while it was inversely associated with stage, pathological T factor, lymph node metastasis, and distant metastasis. Prognostic analyses demonstrated that KLK12 was a favorable prognostic factor for both disease-free and breast cancer-specific survival of the patients. Furthermore, the knockdown of KLK12 significantly increased cell proliferation activity and cell migration of breast cancer cells. These results suggest that KLK12 has antitumorigenic effects associated with proliferation and migration and immunohistochemical KLK12 status as a potent favorable prognostic factor in breast carcinoma patients.

The Pro-Tumorigenic Role of Chemotherapy-Induced Extracellular HSP70 from Breast Cancer Cells via Intratumoral Macrophages

Tumor-associated macrophages (TAMs) contribute to tumor progression and chemoresistance; it is therefore important to clarify the altered functions of macrophages following chemotherapy. While extracellular heat shock protein (HSP) 70 is associated with therapeutic resistance, the effects of HSP70 on TAMs remain largely unknown. Here, we conducted in vitro experiments and immunohistochemistry in 116 breast carcinoma specimens to determine whether the secretion of HSP70 from breast cancer cells following chemotherapy affects macrophage function. It was revealed that the interaction of epirubicin (EPI)-exposed breast cancer cells with macrophages enhanced tumor progression, and EPI promoted the secretion of extracellular HSP70 from breast cancer cells. The expression of pro-tumorigenic macrophage marker CD163 was decreased in macrophages treated with a conditioned medium (CM) from HSP70-silenced breast cancer cells. Breast cancer cells treated with CM from HSP70-silenced breast cancer cells showed decreased expression of transforming growth factor (TGF)-β, and the pro-tumorigenic effects of macrophages were impaired when TGF-β signaling was inhibited. Immunohistochemistry demonstrated that HSP70 served as a poor prognostic factor in conjunction with macrophage infiltration. It was therefore concluded that extracellular HSP70 levels increased following chemotherapy and enhanced the pro-tumorigenic effects of TAMs, either directly or indirectly, by regulating TGF-β expression in breast cancer cells.

In Situ Proximity Ligation Assay to Visualize Protein-Protein Interactions in Tumor Specimens

Protein-protein interactions (PPI) are the basis of various biological phenomena, such as intracellular signal transduction, gene transcription, and metabolism. PPI are also considered to be involved in the pathogenesis and development of various diseases, including cancer. PPI phenomenon and their functions have been elucidated by gene transfection and molecular detection technologies. On the other hand, in histopathological analysis, although immunohistochemical analyses provide information pertaining to protein expression and their localization in pathophysiological tissues, it has been difficult to visualize the PPI of these proteins. An in situ proximity ligation assay (PLA) was developed as a microscopic visualization technique for PPI in formalin-fixed, paraffin-embedded (FFPE) tissues as well as in cultured cells and frozen tissues. PLA using histopathological specimens enables cohort studies of PPI, which can clarify the significance of PPI in pathology. We have previously shown the dimerization pattern of estrogen receptors and significance of HER2-binding proteins using breast cancer FFPE tissues. In this chapter, we describe a methodology for the visualization of PPI using PLA in pathological specimens.

ODP562 ZnT5 Involvement in EMT in Breast Cancer

The zinc levels in breast cancer tissue are reportedly higher than in normal tissue. In addition, the expression levels of zinc transporters, including ZnT5 and ZnT6, in breast cancer tissue are higher than in normal breast tissue. Moreover, ZnT5 and ZnT6 contribute to the formation of heterodimers and are involved in different biological functions. In vitro studies using chicken DT40 cells showed that ZnT5 and ZnT6 heterodimers are required to activate several proteins that play important roles in tumorigenesis, infiltration, and metastasis. However, the functions of ZnT5 and ZnT6 heterodimers in breast cancer remain unknown. Therefore, in this study, we first immunolocalized ZnT5 and ZnT6 in 113 pathological specimens of breast cancer. We then analyzed the interaction between ZnT5 and ZnT6 in breast cancer tissue using proximity ligation assay (PLA). Further, we evaluated cell migration and the expression of epithelial mesenchymal transition (EMT) markers as well as vimentin and E-cadherin in ZnT5 knockdown MCF-7 cells using siRNA. Next, we utilized human phosphorylation multipathway profiling array to explore the underlying mechanism of ZnT5 knockdown-induced cell migration. Immunohistochemical analysis revealed that the number of ZnT5-positive breast cancer cells was significantly higher in patients with a low pathologic N factor, and the number of ZnT6-positive breast cancer cells was significantly higher in patients with a low histological grade. The number of ZnT5 and ZnT6 double-positive breast cancer cells was significantly higher in patients with low Ki-67 expression than those with ZnT5-positive and ZnT6-negative breast cancer cells. In addition, ZnT5 and ZnT6 heterodimers were detected using PLA in breast cancer tissues with high expression of both ZnT5 and ZnT6. Treatment with 100 µM ZnCl 2 inhibited migration of MCF-7 cells, but ZnT5 knockdown promoted cell migration. ZnT5 knockdown induced higher levels of vimentin and lower levels of E-cadherin and activated SMAD1 in the presence of 100 µM ZnCl 2 . These results indicate that the involvement of ZnT5 in the inhibition of EMT through SMAD1 inactivation. These results also indicate that the role of ZnT5 and ZnT6 heterodimers differs from that of the ZnT5 homodimer in cell proliferation. However, further studies are required to clarify the role of zinc transporters and zinc signaling in breast cancer.

Presentation: No date and time listed

ODP548 Fatty acid metabolism-related factors in breast and endometrial cancers

Obesity is a well-known risk factor for gynecological malignant tumors such as breast and endometrial cancers. In the cancer microenvironment, the interaction between cancer cells and adipocytes reportedly contributes to the malignant behavior of cancer. In breast cancer, the fatty acid transporter CD36, also known as fatty acid translocase, has been shown to mediate fatty acid uptake into cancer cells and activate signaling pathways that promote tumor progression. Fatty acids are speculated to play important roles in breast and endometrial cancer; however, detailed mechanisms remain unclear. In the present study, we first examined the expression of CD36 and acyl-CoA dehydrogenase long chain (ACADL) in breast (30 cases) and endometrial (35 cases) cancer tissues using immunohistochemistry. CD36 is a membrane protein that transports long-chain fatty acids, and ACADL catalyzes the initial β-oxidation reaction. We detected no correlation between the CD36 status and clinicopathological factors, including the estrogen receptor status in breast cancer tissues. CD36 status revealed a significant positive correlation with lymph node metastasis in endometrial cancer. There was no immunoreactivity for CD36 in morphologically normal mammary glands. Otherwise, CD36 immunoreactivity was detected in the endometrial glandular cells. In both cancers, ACADL expression did not correlate with any clinicopathological factor. Both CD36 and ACADL showed higher positivity rates in endometrial cancer than in breast cancer. In addition, the effect of lipid addition on cell proliferation was examined using breast (T-47D) and endometrial (AN3CA) cancer cell lines exhibiting equivalent CD36 levels. Lipid (Refeed JNS) was obtained from Remembrane, Italy. Lipid addition promoted cell proliferation in both T-47D and AN3CA cells. Intracellular fatty acid β-oxidation (FAO) was visualized using FAOBlue (Funakoshi, Tokyo, Japan), a nonanoic acid (C9) derivative of coumarin, a blue fluorescence dye. Following FAOBlue decomposition in the fourth FAO cycle, coumarin is released from propionic acid, and released coumarin shows strong blue fluorescence excited at 405 nm. T-47D cells showed blue fluorescence in the lipid-supplemented medium, indicating β-oxidative activity. Conversely, AN3CA cells exhibited weak fluorescence under the same conditions. It can be postulated that intracellular lipid uptake and subsequent β-oxidation are mediated via a specific pathway in breast and endometrial cancers. Lipid-mediated effects differ between breast and endometrial cancers, and further investigations are needed to elucidate intracellular signals mediating these effects.

Presentation: No date and time listed

ODP559 The prognostic role of IL-17A-neutrophils crosstalk in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer that is characterized by extensive intratumoral heterogeneity. At this juncture, TNBCs are treated with conventional chemotherapy and have few targeted therapies. Due to the presence of increased tumor-infiltrating lymphocytes and immune-checkpoint molecules, TNBCs are considered highly immunogenic. This provides an opportunity to explore various immunotherapeutic options. The immune cells such as Th17 cells or neutrophils (tumor-associated neutrophils; TANs) can secrete a pro-inflammatory cytokine called IL-17A, which is known to be associated with poor outcomes in several cancers. TANs are related to tumor progression and are influenced by certain chemokines. Meanwhile, IL-17A can also regulate chemokine (C-X-C motif) ligand 1 (CXCL1), which is a strong chemoattractant for TANs and can lead to the growth of tumors in breast cancer. However, the significance of IL-17A and its interaction with TANs and CXCL1 has yet not been clearly understood in TNBC. For this purpose, formalin-fixed paraffin-embedded biopsy tissue specimens of 109 Japanese TNBC patients were included in this study. Immunohistochemistry was performed to assess the status of IL-17A, CXCL1, and CD66b (a neutrophil marker) and to understand their correlation among each other, with clinical parameters, and with the outcomes of patients. Also, in vitro studies were performed to evaluate the effect of recombinant IL-17A on TNBC cell lines proliferation, migration, and CXCL1 expression. Clinical results revealed that IL-17A was significantly correlated with CXCL1 and CD66b, which suggested potential crosstalk between them. On the other hand, CXCL1 significantly and CD66b tended to be correlated with tumor size. Also, CD66b was significantly correlated with the Ki-67 labeling index, showing that TANs may have a role in tumor cell proliferation. Kaplan-Meier survival curves showed that high IL-17A was significantly associated with poor disease-free and overall survival, indicating the poor outcome of the TNBC patients. To our great interest, in vitro results revealed that no difference was observed for proliferation or migration of TNBC cell lines (was only observed in the MDA-MB-231 cell line) after treatment with recombinant IL-17A. However, CXCL1 was highly up-regulated in a dose and time-dependent manner after exposure to IL-17A, indicating that IL-17A might be involved in the recruitment of neutrophils through up-regulation of CXCL1. Therefore, we concluded that IL-17A was a poor prognostic factor for TNBC patients, enhancing the chemokine-neutrophil recruitment to the tumor site, leading to tumor progression and aggression. In the future, we intend to explore different pathways for understanding the mechanism of CXCL1 up-regulation by IL-17A.

Presentation: No date and time listed

ODP543 Chemotherapy-induced extracellular HSP70 enhances pro-tumorigenic effects of macrophages in breast cancers

Breast cancer is one of the most common types of malignancies in women worldwide. Cytotoxic chemotherapy has improved the prognosis of aggressive phenotype of breast cancer patients including triple-negative breast cancers. However, resistance to chemotherapy is an important problem. Tumor-associated macrophages (TAMs) are primary components of tumor microenvironment and promote tumor progression by releasing various cytokines. Pro-tumorigenic effects of TAMs are known to induce chemoresistance in breast cancers. On the other hand, we previously showed that pro-tumorigenic effects of TAMs were enhanced in breast cancer tissues following chemotherapy by immunohistochemical study. Here, we demonstrated that breast carcinoma cells exposed by chemotherapy induced pro-tumorigenic effects of TAMs. THP-1 human monocyte cell-derived macrophages were interacted with MDA-MB-231 and MDA-MB-453 human breast cancer cells treated with epirubicin (EPI), and conditioned media from them significantly promoted proliferation and migration of breast cancer cells. We found that the expression of heat shock protein (HSP) 70 in the cytoplasm of MDA-MB-231 cells was upregulated following EPI treatment. HSP70 is an intracellular molecular chaperone and recently described with extracellular actions in stressful conditions. However, extracellular HSP70 action on TAMs in breast cancer has remained largely unknown. MDA-MB-231 cells treated with EPI and EPI-resistant MDA-MB-231 subline promoted secretion of HSP70, especially exosomal HSP70. Then, HSP70 knockdown in MDA-MB-231 cells were performed using siRNA. Macrophages cultured with HSP70 suppressed conditioned media from MDA-MB-231 cells showed decreased expression of CD163, a marker of pro-tumorigenic macrophages. Furthermore, HSP70 suppressed conditioned media downregulated the expression of transforming growth factor (TGF)-beta and colony stimulating factor (CSF)-1 in MDA-MB-231 cells, which are known to increase pro-tumorigenic effects of macrophages. Then, we performed immunohistochemistry for HSP70 in 116 breast carcinoma tissues. HSP70 immunoreactivity in the cytoplasm of breast carcinoma cells was correlated with stage, lymph node metastasis, pathological T factor, histological grade, Ki-67 LI, and negatively correlated with ER and progesterone receptor (PR). Furthermore, immunoreactivity of HSP70 was increased in breast cancer patients who had received neoadjuvant chemotherapy. When we correlated HSP70 with clinical outcome, HSP70 immunoreactivity was correlated with increased risk of recurrences and breast-cancer-specific mortality. Importantly, macrophage infiltration was correlated with increased risk of recurrences only in the HSP70 positive group, but not in the HSP70-negative group, which indicates that HSP70 may be associated with the pro-tumorigenic effects of TAMs in breast cancers. Taken together, breast carcinoma cells promoted secretion of extracellular HSP70 following chemotherapy and it might induce chemoresistance by upregulating pro-tumorigenic effects of macrophages, directly or indirectly via regulation of cytokines expression in breast carcinoma cells. Extracellular HSP70 may be an important target to improve the prognosis of breast cancer patients.

Presentation: No date and time listed

Immunolocalization of CD80 and CD86 in Non-Small Cell Lung Carcinoma: CD80 as a Potent Prognostic Factor

It has been demonstrated that tumor cells express programed cell death protein 1 (PD-L1) to escape T lymphocytes that express programed cell protein 1 (PD-1), and PD-1/PD-L1 immune checkpoint inhibitors have been regarded in lung cancer patients. CD80 and CD86 are members of B7 superfamily which regulates T lymphocyte activation and tolerance. However, immunolocalization of CD80 and CD86 has not been examined in the lung carcinoma tissues and their clinical significance remains unknown. Therefore, to clarify clinical significance of CD80 and CD86, we immunolocalized these in 75 non-small cell lung carcinomas (NSCLC) in this study. Immunoreactivities of CD80 and CD86 were mainly detected in tumor-infiltrating macrophages. Immunohistochemical CD80 status was high in 56% of NSCLC, and it was positively associated with stage, pathological T factor, distant metastasis, histological type and PD-L1 status. Moreover, multivariate analysis turned out that the CD80 status was an independent worse prognostic factor. CD86 status was high in 53% of the cases, but it was not significantly associated with any clinicopathological parameters. These findings suggest that CD80 is a potent worse prognostic factor possibly in association with escape from immune attack in NSCLC.

Vasohibin-1 and -2 in pulmonary lymphangioleiomyomatosis (LAM) cells associated with angiogenic and prognostic factors

Lymphangioleiomyomatosis (LAM) is a rare pulmonary neoplasm, clinically associated with dyspnea and respiratory failure. Current therapeutic modalities do not necessarily reach satisfactory outcome and novel therapeutic approaches are currently warranted. Therefore, in this study, we focused on vasohibin-1 (VASH1) and -2 (VASH2); VASH1 terminated and VASH2 promoted angiogenesis. In addition, both VASH1/2 were reported to influence the progression of various human malignancies. We first performed hierarchical clustering analysis to attempt to classify 36 LAM cases into three different clusters according to immunoreactivity of VASH1/2 and other angiogenic and prognostic factors of LAM; VEGFR1/2/3, p-mTOR, p-S6, p-4EBP, ERα, PgR, MMP2, and MMP9. The cluster harboring higher angiogenic factors had higher VASH1/2 status. VASH1 was significantly positively correlated with VEGFR2, MMP9, and p-mTOR (p-value <0.05), and VASH2 with both angiogenic and prognostic factors including VEGFR1, PgR, MMP9, p-mTOR, p-S6, and p-4EBP (p-value <0.05). Subsequent PCR array of angiogenic genes demonstrated that high VASH1 mRNA was significantly positively associated with the status of SPHK1 and TYPM, lower EGF and EFNB2 (p-value <0.05), and high VASH2 mRNA negatively with MMP2 (p-value <0.05). VASH1 was considered to be up-regulated by activation of angiogenesis, whereas VASH2 could influence the angiogenesis and progression of LAM.

Visualization of the protein-protein interactions of hormone receptors in hormone-dependent cancer research

In hormone-dependent cancers, the activation of hormone receptors promotes the progression of cancer cells. Many proteins exert their functions through protein-protein interactions (PPIs). Moreover, in such cancers, hormone-hormone receptor binding, receptor dimerization, and cofactor mobilization PPIs occur primarily in hormone receptors, including estrogen, progesterone, glucocorticoid, androgen, and mineralocorticoid receptors. The visualization of hormone signaling has been primarily reported by immunohistochemistry using specific antibodies; however, the visualization of PPIs is expected to improve our understanding of hormone signaling and disease pathogenesis. Visualization techniques for PPIs include Förster resonance energy transfer (FRET) and bimolecular fluorescence complementation analysis; however, these techniques require the insertion of probes in the cells for PPI detection. Proximity ligation assay (PLA) is a method that could be used for both formalin-fixed paraffin-embedded (FFPE) tissue as well as immunostaining. It can also visualize hormone receptor localization and post-translational modifications of hormone receptors. This review summarizes the results of recent studies on visualization techniques for PPIs with hormone receptors; these techniques include FRET and PLA. In addition, super-resolution microscopy has been recently reported to be applicable to their visualization in both FFPE tissues and living cells. Super-resolution microscopy in conjunction with PLA and FRET could also contribute to the visualization of PPIs and subsequently provide a better understanding of the pathogenesis of hormone-dependent cancers in the future.

The Visualization of Protein-Protein Interactions in Breast Cancer: Deployment Study in Pathological Examination

The therapeutic strategy is determined by protein expression using immunohistochemistry of estrogen receptor (ER), progesterone receptor, and human epidermal growth factor receptor 2 (HER2) in formalin-fixed paraffin-embedded (FFPE) breast cancer tissues. However, few proteins function independently, and many of them functions due to protein-protein interactions (PPIs) with other proteins. Therefore, it is important to focus on PPIs. This review summarizes the PPIs of ER and HER2 in breast cancer, especially those using a proximity ligation assay that can visualize PPIs in FFPE tissues. In particular, assessing the interaction of CEACAM6 with HER2 may serve as a surrogate marker for the efficacy of trastuzumab in patients with breast cancer. Therefore, in this review, the technique used to detect the interaction of CEACAM6 and HER2 in routinely processed pathological specimens will be applied to the clinical practice of drug selection. We showed the possibility as a novel pathological examination method using PPIs.

B7-1 and programmed cell death-ligand 1 in primary and lymph node metastasis lesions of non-small cell lung carcinoma

Background

Programmed cell death ligand 1 (PD‐L1) status has been reported to be different between metastatic and primary lesions in some cases. Therefore, the interaction between carcinoma and immune cells could influence their expression in the tumor microenvironment. PD‐L1 is known to bind not only to Programmed cell death 1 (PD‐1) but also to B7‐1 (CD80). In this study, we examined the interaction between lung carcinoma cell lines and peripheral blood mononuclear cells (PBMCs) in vitro. We then examined the significance of B7‐1 expression non‐small cell lung cancer (NSCLC) microenvironment.

Methods

The interaction of lung carcinoma cell lines and PBMC through the soluble factors was analyzed using a co‐culture system. The changes in expression of immune checkpoint‐related factors in PBMC were examined by PD‐1/PD‐L1 Checkpoint Pathway qPCR Array Kit. B7‐1 expression in NSCLC tissues was examined by immunohistochemistry.

Results

B7‐1 was upregulated following the co‐culture with the lung carcinoma cell lines. B7‐1 expression in NSCLC tissues was significantly higher in smokers and squamous cell carcinomas and was significantly positively correlated with PD‐L1 status in primary cancer. However, B7‐1 and PD‐1 were not correlated between primary and metastatic diseases in the same patients.

Conclusion

PD‐1 inhibitors inhibited PD‐1/PD‐L1 binding but not PD‐L1/B7‐1 binding. These results demonstrated that the intratumoral ratio of B7‐1 positive T cells in NSCLC tissue could be involved in the therapeutic efficacy of PD‐L1 inhibitors. This study focused on lymph node metastasis but other sites of distant metastases should be explored by further analysis.

Incidental findings on computed tomography for preoperative assessment before transcatheter aortic valve implantation in japanese patients

Background

Extra-cardiovascular incidental findings (IFs) on preoperative computed tomography (CT) are frequently observed in transcatheter aortic valve implantation (TAVI) candidates. However, the backgrounds of TAVI candidates and comorbidities differ based on the race and/or country, and data on IFs in a specific population are not always applicable to another.

Objective

To assess the prevalence, type, and clinical impact of IFs in Japanese TAVI candidates.

Methods

This was a retrospective, single-center, observational study. CT reports of 257 TAVI candidates were reviewed, and IFs were classified as (a) insignificant: findings that did not require further investigation, treatment, or follow-up; (b) intermediate: findings that needed to be followed up or were considered for further investigation but did not affect the planning of TAVI; and (c) significant: findings that required further investigation immediately or affected the planning of TAVI.

Results

At least one IF was found in 254 patients (98.8%). Insignificant, intermediate, and significant IFs were found in 253 (98.4%), 153 (59.5%), and 34 (13.2%) patients, respectively. Newly indicated significant IFs were found in 19 patients (7.4%). In 2 patients (0.8%), TAVI was canceled because of significant IFs. In patients who consequently underwent TAVI, the presence of significant IFs was not associated with the duration from CT performance to TAVI [28 (19–40) days vs. 27 (19–43) days, p=0.74] and all-cause mortality during the median follow-up period of 413 (223–805) days (p=0.44).

Conclusion

Almost all Japanese TAVI candidates had at least one IF, and the prevalence of significant IFs was not negligible. Although the presence of significant IFs was not associated with mid-term mortality, appropriate management of IFs was considered important.

Funding Acknowledgement

Type of funding sources: None.

Regression of electrocardiographic left ventricular hypertrophy after transcatheter aortic valve replacement for aortic stenosis

Background

The changes in electrocardiographic left ventricular hypertrophy (ECG-LVH) after transcatheter aortic valve replacement (TAVR) are not fully elucidated.

Methods

This retrospective single-center study investigated 156 patients who underwent TAVR for severe aortic stenosis. Twelve-leads ECGs obtained before and at 2 days and 1, 6 and 12 months after TAVR were analyzed. Patients with an implanted pacemaker, with a bundle branch block before or after TAVR or whose electrocardiogram at any measuring point was not available were excluded. As an assessment of ECG-LVH, Sokolow-Lyon voltage, Cornell voltage, Cornell product and Peguero–Lo Presti voltage were evaluated.

Results

Finally, 64 patients were included. Sokolow-Lyon voltage, Cornell voltage, Cornell product and Peguero–Lo Presti voltage significantly decreased between 1 and 6 months after TAVR compared to baseline. The prevalence of ECG-LVH criteria for each parameter decreased as well. QRS duration significantly decreased at 6 months after TAVR and the number of patients with strain pattern decreased significantly at 1 month when compared to baseline. When the patients were divided into two groups, those with and without ECG-LVH at baseline, ECG-LVH parameter values decreased significantly, especially in patients with ECG-LVH at baseline.

Conclusion

Regression of ECG-LVH after TAVR was demonstrated as per various criteria of ECG-LVH. The voltages and prevalence of ECG-LVH decreased significantly between 1 and 6 months after TAVR.

Funding Acknowledgement

Type of funding sources: None.

Forkhead Box I1 in Breast Carcinoma as a Potent Prognostic Factor

Forkhead box (FOX) proteins are family of transcriptional factors and regulate cell growth and differentiation as well as embryogenesis and longevity. Previous studies have demonstrated that several FOX members regulate growth or metastasis of breast carcinoma, but clinical significance of total FOX members remains unclear. We first examined associations between expression of 40 FOX genes and TNM status of 19 breast carcinoma using microarray data. Subsequently, we immunolocalized FOXI1 in 140 breast carcinomas and evaluated its clinicopathological significance. In the microarray analysis, we newly identified that gene expression of FOXI1 was most pronouncedly linked to metastasis of the breast carcinoma among the FOX members examined. However, clinicopathological significance of FOXI1 has not been examined in the breast carcinoma. FOXI1 immunoreactivity was positive in 44 out of 140 (31%) of breast carcinomas, and it was significantly associated with stage, lymph node metastasis and distant metastasis. The FOXI1 status was significantly associated with worse prognosis of the breast cancer patients, and it turned out to be an independent prognostic factor for both distant disease-free survival and breast cancer-specific survival. These findings suggest that FOXI1 plays important roles in the metastasis of breast carcinoma and immunohistochemical FOXI1 status is a potent prognostic factor.

D-2-hydroxyglutarate dehydrogenase in breast carcinoma as a potent prognostic marker associated with proliferation

BACKGROUND

D-2-hydroxyglutarate dehydrogenase (D2HGDH) catalyzes D-2-hydroxyglutarate to α-ketoglutarate and is involved in the regulation of cellular energy and biosynthetic intermediates. Previously, D2HGDH was reported to decrease 2-hydroxyglutarate level in breast carcinoma cells, but no other report has examined D2HGDH in breast carcinoma, and its significance remains unknown.

METHODS

We first immunolocalized D2HGDH in 224 invasive breast carcinomas and evaluated its clinicopathological significance. We next examined associations between gene expression of D2HGDH and α-ketoglutarate-dependent dioxygenases in 23 breast carcinoma tissues using the gene expression profile data. Finally, we examined the effects of D2HGDH on the proliferation in three breast carcinoma cells.

RESULTS

D2HGDH immunoreactivity was detected in 49% of invasive breast carcinomas, and the immunohistochemical D2HGDH status was positively associated with histological grade, HER2 and Ki-67, while it was inversely associated with estrogen receptor. Moreover, it was significantly associated with worse prognosis of the breast cancer patients, and it turned out to be an independent prognostic factor for both the disease-free and breast cancer-specific survival in these patients. Gene expression profile data revealed that D2HGDH expression was positively associated with the expression of 6 α-ketoglutarate-dependent dioxygenases (KDM3A, PLOD1, EGLN2, ALKBH1, ASPH and ALKBH7). Consequent in vitro experiments demonstrated that D2HGDH overexpression significantly increased the cell proliferation activity of MCF-7, T47D and MDA-MB-231 cells.

CONCLUSION

These results suggest that D2HGDH plays an important role in the growth of breast carcinoma, possibly through regulating functions of α-ketoglutarate-dependent dioxygenases, and that D2HGDH status is a potent worse prognostic factor in breast cancer patients.

Breast Cancer, Diabetes Mellitus and Glucagon-Like Peptide-1 Receptor Toward Exploring Their Possible Associations

PURPOSE

Diabetes Mellitus (DM) has been one of the well known risk factors of breast cancer (BC) development and also associated with adverse clinical outcomes of BC patients. Glucagon-like peptide-1 (GLP-1) receptor agonists have been used as antidiabetic therapeutic agents and recent epidemiological studies have reported their use to be correlated with increased BC risks. However, biological or pathological details have remained unknown. Therefore, in this study, we examined the status of GLP-1 receptor (GLP-1R) in BC with and without DM and correlated the findings with the clinicopathological factors of the patients to explore the possible involvement of GLP-1 in BC pathology.

METHODS

We immunolocalized GLP-1R in cancer and adjacent non-pathological breast tissues in BC patients with DM (125 cases) and without DM (58 cases). We then compared the status of GLP-1R with that of fibroblast growth factor 7 (FGF7) and fibroblast growth factor receptor 2 (FGFR2), Ki-67 labeling index (Ki-67 LI) and disease free survival (DFS) of the patients and also between cancerous and non-pathological breast tissues.

RESULTS

GLP-1R immunoreactivity was significantly higher (p = 0.044) in the patients with DM than without in carcinoma tissues. However, this was detected only in invasive carcinoma (p < 0.01) and not in non-invasive carcinoma nor non-pathological mammary glands. FGF7 was significantly correlated with the status of GLP-1R in BC (p = 0.045). In addition, in ER positive BC cases, those with GLP-1R positive status tended to have higher Ki-67 LI of more than 14% (p = 0.070).

CONCLUSION

These findings all demonstrated the possible association between GLP-1R status and biological features of BC, especially of invasive BC in DM patients.

Abstract 724: FE65 in breast cancer patients and its clinicopathological significance

FE65 is well known to bind with amyloid precursor protein (APP), translocate FE65-APP complex into nucleus and modulate gene transcription. APP was reported to be closely associated with breast cancer progression but clinical significance of FE65 has remained virtually unknow. We first studied 88 surgical pathology specimens with their clinicopathological factors. Results showed nuclear FE65 immunoreactivity was significant positively correlated with estrogen receptor (ER) status (P=0.054) and inversely with histological grade of the patients(P=0.038). We then analyzed 145 ER positive cases which include 44 ductal carcinomas in situ (DCIS) cases and 101 invasive ductal carcinoma (IDC) cases. The number of FE65 positive carcinoma cells was significantly higher in IDC than DCIS (P=0.0395). We then performed in vitro wound healing assay, which demonstrated that FE65 knock-down cells migrated slower than control groups (P=0.0495). FE65 formed the complex with APP and in order to further elucidate their detailed intracellular binding status, proximity ligation assay (PLA) was employed. Binding of APP and FE65 was detected in the cytoplasm with that of ER and FE65 in the nucleus. These results demonstrated that FE65 first bound to APP in the cytoplasm and was then released into the nucleus after phosphorylation of APP. This released FE65 in the nuclei could interact with ER to promote cell migration. Based on those results above, we then conducted the WST-8 assay to further elucidate the possible involvement of FE65 in cell survival. FE65 influenced response of tamoxifen in breast carcinoma cells, and the survival rate of those knocked down by FE65 siRNA was significantly higher than that of the control siRNA group(P=0.0039), indicating that FE65 could contribute to increase the sensitivity of tamoxifen action.In summary, FE65 was demonstrated to stimulate cell proliferation and migration, possibly as a result of the interaction of FE65 with APP in the cytoplasm and ER in the nuclei. In addition, FE65 could enhance the actions of tamoxifen by increasing ER expression and subsequent availability of its binding to ER.

Citation Format: Junyao Xu, Erina Iwabuchi, Yasuhiro Miki, Ayako Kanai, Takanori Ishida, Hironobu Sasano. FE65 in breast cancer patients and its clinicopathological significance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 724.

Abstract 726: Correlation between T cell infiltration subtypes and intratumoral hormone levels in endometrial cancer

T cells in the tumor microenvironment, or tumor-infiltrating lymphocytes (TILs), have been recognized to play a critical role in tumor immunity. TILs are heterogeneously defined, and different T cell subsets have various effects. The properties of some T cell markers, such as CD3, CD4, CD8, and forkhead box P3 (FOXP3), are poor prognostic factors in several types of cancers. The effects of sex steroid hormones on T cell function in inflammation are known, and estrogen and androgen regulate the secretion of cytokines to enhance and attenuate, respectively, the immune response. While intratumoral estrogen and androgen synthesis plays an important role in the progression of cancer cells in hormone-dependent cancers, the relationship between intratumoral hormone levels and TIL subtypes is unclear. In this study, we examined the correlation between intratumoral hormone concentrations and expression scores of TIL markers in endometrial cancer. We employed frozen and formalin-fixed paraffin-embedded (FFPE) tissues of 19 endometrial cancer tissues (G1, n=6; G2, n=5; G3, n=6; Serous, n=2). Hormone concentrations were measured by LC-MC/MS from the frozen sample, and immunohistochemistry of T cell markers was performed using FFPE tissues. The five T cell markers examined in this study were CD3 (total T cells), CD4 (helper T cells), CD8 (cytotoxic T cells), FOXP3 (regulatory T cells), and thymocyte selection-associated HMG box (TOX) (exhausted T cells). The number of intratumoral CD3 in an arbitrary two-field (magnification, ×200) was counted and used as the CD3 score. Similarly, the number of other markers was counted, and the ratio to CD3 was used as the score for each marker. A correlation was found between TOX and CD8 using correlation between markers. The median scores for CD3 and CD8 were significantly higher in type 1 (G1 and G2) than in type 2 (G3 and serous) (CD3, p=0.031; CD8, P=0.031). The CD4 score had a positive correlation with estrogen (estrone, r2=0.591; estradiol, r2=0.501) and androgen (dihydrotestosterone, r2=0.327) concentrations. There was a poor negative correlation between cortisol concentration and CD8 score (r2=0.203). Estrogen and androgen at the tumor in situ were considered to affect TILs, especially CD4 positive T cells. It is also suggested that cortisol acts on immunosuppression, even locally in the tumor. This study showed the potential of a combination of immunotherapy and hormone therapy in endometrial cancer.

Citation Format: Yasuhiro Miki, Fuka Onuma, Kiyoshi Takagi, Erina Iwabuchi, Takashi Suzuki, Hironobu Sasano, Kiyoshi Ito. Correlation between T cell infiltration subtypes and intratumoral hormone levels in endometrial cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 726.

Estrogen Receptor β Is Involved in Acquired Resistance to EGFR-tyrosine Kinase Inhibitors in Lung Cancer

BACKGROUND/AIM

Acquired resistance to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) has posed serious clinical problems in the treatment of lung adenocarcinoma (LADC) patients harboring relevant EGFR mutations. In this study, we explored the role of estrogen receptor β (ERβ) in the development of acquired resistance to EGFR-TKIs in human LADC.

MATERIALS AND METHODS

First, the role of ERβ in erlotinib resistance of LADC cell lines (PC9/ER) was examined. Then, the immunolocalization of ERβ in 28 LADC patient samples treated with EGFR-TKIs was investigated.

RESULTS

Cytoplasmic ERβ was upregulated in erlotinib resistant cell lines. EGFR-TKIs sensitivity increased with ERβ inhibition in PC9/ER cells. ERK1/2 and AKT activities were both markedly increased by specific ERβ agonists even under erlotinib treatment of PC9/ER cells. Cytoplasmic ERβ immunoreactivity was significantly associated with clinical response to EGFR-TKIs.

CONCLUSION

Cytoplasmic ERβ in LADC cells was involved in the development of resistance to EGFR-TKIs.

Heterogeneous Nuclear Ribonucleoprotein K Is Involved in the Estrogen-Signaling Pathway

Heterogeneous nuclear ribonucleoprotein K (hnRNPK) has been found in the nucleus, cytoplasm, and mitochondria. It is implicated in chromatin remodeling, transcription, splicing, and translation processes. Although hnRNPK has reportedly been associated with poor prognosis in colon cancer patients, it is beneficial in gastric cancer as it inhibits cancer cell proliferation. Expression of hnRNPK in ER (Estrogen receptor) -positive/PR (Progesterone receptor) -positive breast cancer was higher than other subtypes; however, the biological functions of hnRNPK in the ER-mediated signaling pathway have not been identified. In this study, we investigated the functions of hnRNPK in the estrogen-signaling pathway. We initially evaluated hnRNPK expression upon treatment with estradiol (E2) and ICI 182,780 in ERα-positive breast cancer cell line MCF-7. This initial evaluation revealed that expression of hnRNPK was increased by E2 treatment but decreased by ICI 182,780 treatment. We further evaluated the effects of estrogen-signaling pathway in hnRNPK knockdown MCF-7 cells using siRNA, which revealed that hnRNPK knockdown decreased ERα expressions and ERα target gene TFF1 by E2 treatment. In addition, we examined the interaction between hnRNPK and ERα because hnRNPK has been reported to interact with several other proteins. These interactions were detected using immunoprecipitation and proximity ligation assay. We then immunolocalized hnRNPK in breast cancer and endometrial cancer. hnRNPK expression was significantly higher in ERα-positive cancer cells in both breast and endometrial cancers. In contrast, hnRNPK expression was significantly lower in Ki-67-positive breast cancer while being significantly higher in Ki-67-positive endometrial cancer. hnRNPK has been found to function differently, depending on the type of cancer (breast or endometrial) that it is expressed in. However, further studies are required to clarify the clinical significance of hnRNPK in breast and endometrial cancer patients.

Microtubule-Associated Protein 2 as a DHEA Binding Protein in Endometrial Cancer

Dehydroepiandrosterone (DHEA) is an androgen secreted by the adrenal glands, but its binding affinity for the androgen receptor is very low. DHEA is transformed into androstenedione by 3β-hydroxysteroid dehydrogenase (HSD) and then into testosterone by 17β-HSD type 5, or into estrone by aromatase. DHEA is also converted into androstenediol by 17β-HSD type 1. Therefore, DHEA is considered to play an important role as a precursor hormone for sex steroid hormones. We performed a search for a protein having an amino acid sequence homology to the DHEA binding site of 17β-HSD type 1, and found that microtubule-associated protein 2 (MAP2) binds to DHEA (Laurine E et al., J Biol Chem. 2003). MAP2 expression is necessary for neurite extension and cessation of cell division. MAP2 is known to suppress migration and invasion and affect the assembly, stabilization, and bundling of microtubules in melanoma cells, but the function of MAP2 in endometrial cancer has not been clarified. In this study, we investigated the expression of MAP2 and its association with DHEA in order to clarify the direct non-receptor action of DHEA in endometrial cancer. We employed frozen and formalin-fixed paraffin-embedded (FFPE) tissues of 35 endometrial cancer tissues (G1, n=12; G2, n=10; G3, n=9; Serous, n=4). Hormone concentrations were measured by liquid chromatograph-tandem mass spectrometer from the frozen sample, and immunohistochemistry of MAP2 was performed using FFPE tissues. We also examined MAP2 immunoreactivity using 59 normal endometrial tissues (proliferative phase, n=33; secretory phase, n=26) of FFPE tissue microarray slides. MAP2 immunoreactivity was found in the cytoplasm of endometrial cancer cells, and the MAP2-positive rate was significantly higher in type 1 (G1 and G2) than in type 2 (G2 and G3). The cell proliferation marker Ki-67 index was significantly lower in the MAP2-positive group. MAP2 was also detected in the glandular epithelial cells of the normal endometrium. The MAP2-positive rate was lower in the proliferative phase than in the secretory phase. Furthermore, the concentration of DHEA in the cancer tissue was significantly higher in the MAP2-positive group than in the MAP2-negative group. MAP2 is known to act on the stability of microtubules and is thought to be involved in the suppression of proliferation and infiltration in cancer cells. It was suggested that DHEA is involved in the stabilization of MAP2 and suppresses the progression of cancer in a hormone receptor-independent manner.

Isoforms of IDH in breast carcinoma: IDH2 as a potent prognostic factor associated with proliferation in estrogen-receptor positive cases

BACKGROUND

Isocitrate dehydrogenase (IDH) is an important enzyme that oxidatively decarboxylates isocitrate to α-ketoglutarate, and three isoforms (IDH1-3) have been identified. Overexpression and/or downregulation of IDH isoforms was reported in several human malignancies, suggesting importance of IDH in oncogenesis. However, significance of IDH isoforms remains largely unclear in the breast carcinoma.

METHODS

We immunolocalized IDH1, IDH2 and IDH3α in 226 breast carcinomas and evaluated their clinical significance. Subsequently, we examined effects of IDH2 on proliferation in breast carcinoma cells.

RESULTS

Immunoreactivity of IDH1-3α was detected in 53%, 38% and 41% of breast carcinomas, and the non-neoplastic epithelium was IDH1-positive, IDH2-negative and IDH3α-positive. IDH1 immunoreactivity was inversely associated with pathological T factor (pT) and Ki-67 in the breast carcinoma, while IDH3α immunoreactivity was not significantly associated with clinicopathological factors. IDH2 status was positively correlated with stage, pT, histological grade, HER2, Ki-67 and microvessel density. Moreover, IDH2 status was significantly associated with worse prognosis of the patients, and it turned out an independent prognostic factor for estrogen-receptor (ER) positive patients. These findings were more evident in the IDH1-negative / IDH2-positive/IDH3α-negative subgroup which is the opposite immunohistochemical IDH phenotype of normal mammary epithelium. In vitro studies demonstrated that RNA interference of IDH2 significantly decreased proliferation activity of T47D and SKBR-3 cells.

CONCLUSION

These results suggest that IDH2 is associated with an aggressive phenotype of breast carcinoma through increasing cell proliferation, different from IDH1 and IDH3α, and immunohistochemical IDH2 status is a potent prognostic factor especially in ER-positive breast cancer patients.

Heterogeneous Nuclear Ribonucleoprotein K Is Involved in the Estrogen-Signaling Pathway in Breast Cancer

Heterogeneous nuclear ribonucleoprotein K (hnRNPK) transcripts are abundant in estrogen receptor (ER)- or progesterone receptor (PR)-positive breast cancer. However, the biological functions of hnRNPK in the ER-mediated signaling pathway have remained largely unknown. Therefore, this study analyzes the functions of hnRNPK expression in the ER-mediated signaling pathway in breast cancer. We initially evaluated hnRNPK expression upon treatment with estradiol (E2) and ICI 182,780 in the ERα-positive breast carcinoma cell line MCF-7. The results revealed that E2 increased hnRNPK; however, hnRNPK expression was decreased with ICI 182,780 treatment, indicating estrogen dependency. We further evaluated the effects of hnRNPK knockdown in the ER-mediated signaling pathway in MCF-7 cells using small interfering RNAs. The results revealed that hnRNPK knockdown decreased ERα expression and ERα target gene pS2 by E2 treatment. As hnRNPK interacts with several other proteins, we explored the interaction between hnRNPK and ERα, which was demonstrated using immunoprecipitation and proximity ligation assay. Subsequently, we immunolocalized hnRNPK in patients with breast cancer, which revealed that hnRNPK immunoreactivity was significantly higher in ERα-positive carcinoma cells and significantly lower in Ki67-positive or proliferative carcinoma cells. These results indicated that hnRNPK directly interacted with ERα and was involved in the ER-mediated signaling pathway in breast carcinoma. Furthermore, hnRNPK expression could be an additional target of endocrine therapy in patients with ERα-positive breast cancer.

Suppression of tumor immune microenvironment via microRNA-1 after epidermal growth factor receptor-tyrosine kinase inhibitor resistance acquirement in lung adenocarcinoma

Immunotherapy is considered one of the most important therapeutic strategies for patients with lung adenocarcinoma after the development of epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) resistance. However, useful predictors of immunotherapy for these patients has not been examined well, although the status of the tumor immune microenvironment (TIME), including programmed death-ligand 1 expression and lymphocyte infiltration, has been generally known to provide predictive markers for the efficacy of immunotherapy. This study aimed to clarify novel predictors of immunotherapy following EGFR-TKI resistance in lung adenocarcinoma, especially regarding micro RNA (miRNA). We evaluated the correlation between EGFR-TKI resistance and lymphocyte infiltration, before and after acquiring EGFR-TKI resistance, in 21 cases of lung adenocarcinoma, and further explored this by in vitro studies, using miRNA PCR arrays. Subsequently, we transfected miRNA-1 (miR-1), the most variable miRNA in this array, into three kinds of lung cancer cells, and examined the effects of miR-1 on EGFR-TKI sensitivity, cytokine expression and lymphocyte migration. Histopathological examination demonstrated that infiltration levels of CD8-positive T cells were significantly decreased after development of EGFR-TKI resistance. In vitro studies revealed that miR-1 significantly inhibited EGFR-TKI effect and induction of cytokines, such as C-C motif chemokine ligand 5 and C-X-C motif chemokine ligand 10, causing inhibition of monocyte migration. These results indicate that the upregulated miR-1 might suppress the TIME, following development of EGFR-TKI resistance. Therefore, miR-1 could be a clinically useful marker to predict therapeutic efficacy of immunotherapy in lung adenocarcinoma patients with EGFR-TKI resistance.

Impact of COVID-19 restrictions on the research environment and motivation of researchers in Japan

The environment surrounding researchers has changed significantly in the face of COVID-19 restrictions. An online self-reported questionnaire was completed by 10,557 participants between June 15 and 19, 2020. The impact on work/research activities and harassments under COVID-19 conditions was higher among researchers (1963) compared to non-researchers (8572). We further examined the effect of COVID-19 restrictions on 300 researchers. Women were significantly more likely to report being harassed than males. The overall "decrease in research motivation" was higher in women. The restrictions on research activities because of COVID-19 restrictions caused future anxiety and a decrease in research motivation.

Abstract 3826: The zinc transporters, ZnT5 and ZnT6, in breast cancer

The zinc levels in breast cancer tissue were reported to be higher than those in normal tissue. In addition, the expression levels of zinc transporters, including ZnT5 and ZnT6, in breast cancer were reported to be higher than those in normal breast tissue. ZnT5 and ZnT6 have been also reported to contribute to the formation of heterodimers and be involved in several different biological functions. Among those, autotaxin, matrix metalloproteinase 9, and carbonic anhydrase IX, which have crucial roles in tumor formation, invasion, and metastasis, were reported to require ZnT5–ZnT6 heterodimers for their activation and secretion in the chicken DT40 cells. However, the functions of ZnT5 and ZnT6 heterodimers has remained virtually unknown in breast cancer. Therefore, we first immunolocalized ZnT5 and ZnT6 in pathology specimens of breast cancer. We examined 88 breast cancer specimens in this study. We then analyzed the interaction between ZnT5 and ZnT6 using proximity ligation assay (PLA) in breast cancer tissues and further evaluated cell proliferation and migration in ZnT5 knockdown MCF-7 and T-47D cells using siRNA. Immunohistochemical analysis revealed that the number of ZnT5-positive breast cancer cells was significantly higher in HER2-positive patients and the number of ZnT6-positive breast cancer cells was significantly higher in patients with low histological grade and high ER and PgR expressions. The number of ZnT5 and ZnT6 double-positive breast cancer cells tended to be associated with low stage (p = 0.0577). In addition, ZnT5 and ZnT6 interaction was detected using PLA through high expression of both ZnT5 and ZnT6 in breast cancer tissues. ZnT5 knockdown exerted no effect on cell proliferation in the presence of 100 µM ZnCl2 in MCF-7 and T-47D cells. The 100 µM ZnCl2 treatment inhibited cell migration in MCF-7 and T-47D cells but ZnT5 knockdown promoted cell migration. To the best of our knowledge, this is the first study demonstrating the expressions of ZnT5 and ZnT6 in breast cancer. The results of this study also indicated that both ZnT5 and ZnT6 could be involved in less aggressive subtypes of breast cancer possibly through inhibition of cell migration. Further studies are required to clarify the clinical significance of their interactions in patients with breast cancer.

Citation Format: Erina Iwabuchi, Yasuhiro Miki, Takanori Ishida, Hironobu Sasano. The zinc transporters, ZnT5 and ZnT6, in breast cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3826.

SUN-742 Roles of Progesterone Receptor Isoform B in Non-Small Cell Lung Cancer Tumor Progression

Lung cancer is a leading cause of cancer mortality worldwide. Premenopausal women often has worse survival with advanced stages of the disease compared to postmenopausal women, suggesting an involvement of sex steroids and their receptors in the progression of non-small cell lung cancer (NSCLC). Progesterone receptor (PR) was reported to be involved in an inhibition of NSCLC cell proliferation and correlated with better clinical outcome. In addition, PRB suppressed epidermal growth factor (EGF)-induced NSCLC cell proliferation and activation of ERK1/2, in the absence of progestin. However, clinical and biological significance of PRB in NSCLC patients has remained virtually unknown. Therefore, we performed immunohistochemistry using monoclonal antibody specific to the N-terminus of PRB (250H11 mAb) and 1294mAb which could detect both PRA and PRB in 124 NSCLC cases: 94 adenocarcinoma and 30 squamous cell carcinoma (SCC). Overall survival (OS) was analyzed using the Kaplan-Meier plotter (KM plotter) database, examining the correlation between the status of PRs and survival rate of the patients.

19 cases were immunohistochemically positive for PRB and 23 PRA/B positive NSCLC cases, and all of four cases harboring abundant PRs were also positive for PRB. Therefore, PRB positivity was considered to be significantly correlated with the whole PR (<0.01). Of particular interest, the abundance of PR or PRB was significantly correlated with lower tumor size in total NSCLC (p=0.0395) and SCC (p=0.023), and tended to be correlated with pleural invasion in adenocarcinoma cases (p=0.051). In addition, PRB positive cases tend to have lower tumor size than those positive with PRA/B. The analysis using KM plotter also revealed that PR was a good prognostic factor in total NSCLC patients.

Our data demonstrated that not only PR but also PRB could be a good prognostic factor and have an important role on tumor progressing in NSCLC patients. In order to further elucidate the molecular mechanisms of PRB signaling in NSCLC, we are now performing further in vitro studies. Results of our present study could contribute to the development of novel therapeutic strategies targeting PR and/or PRB in NSCLC patients.

Systemic distribution of progesterone receptor subtypes in human tissues

Progesterone receptor (PR) is expressed in a wide variety of human tissues, including both reproductive and non-reproductive tissues. Upon binding to the PR, progesterone can display several non-reproductive functions, including neurosteroid activity in the central nervous system, inhibition of smooth muscle contractile activity in the gastrointestinal tract, and regulating the development and maturation of the lung. PR exists as two major isoforms, PRA and PRB. Differential expression of these PR isoforms reportedly contributes to different biological activities of the hormone. However, the distribution of the PR isoforms in human tissues has remained virtually unexplored. In this study, we immunolocalized PR expression in various human tissues using PR (1294) specific antibody, which is capable of detecting both PRA and PRB, and PRB (250H11) specific antibody. Tissues from the uterus, ovary, breast, placenta, prostate, testis, cerebrum, cerebellum, pituitary, spinal cord, esophagus, stomach, small intestine, colon, pancreas, liver, kidney, urinary bladder, lung, heart, aorta, thymus, adrenal gland, thyroid, spleen, skin, and bone were examined in four different age groups (fetal, pediatric, young, and old) in male and female subjects. PR and PRB were detected in the nuclei of cells in the female reproductive system, in both the nuclei and cytoplasm of pituitary gland and pancreatic acinar cells, and only in the cytoplasm of cells in the testis, stomach, small intestine, colon, liver, kidney, urinary bladder, lung, adrenal gland, and skin. Of particular interest, total PRB expression overlapped with that of total PR expression in most tissues but was negative in the female fetal reproductive system. The findings indicate that progesterone could affect diverse human organs differently than from reproductive organs. These findings provide new insights into the novel biological roles of progesterone in non-reproductive organs.

11β hydroxysteroid dehydrogenase 1: a new marker for predicting response to immune-checkpoint blockade therapy in non-small-cell lung carcinoma

Background

Understanding the status of intratumoural immune microenvironment is necessary to ensure the efficacy of immune-checkpoint (IC) blockade therapy. Cortisol plays pivotal roles in glucocorticoid interactions in the immune system. We examined the correlation between intratumourally synthesised cortisol through 11β hydroxysteroid dehydrogenase (HSD) 1 and the immune microenvironment in non-small-cell lung carcinoma (NSCLC).

Methods

We correlated 11βHSD1 immunoreactivity in 125 cases of NSCLC with the amount of intratumoural immune cells present, and 11βHSD1 immunoreactivity with the efficacy of IC blockade therapy in 18 specimens of NSCLC patients. In vitro studies were performed to validate the immunohistochemical examination.

Results

11βHSD1 immunoreactivity showed a significant inverse correlation with the number of tumour-infiltrating lymphocytes and CD3- or CD8-positive T cells. 11βHSD1 immunoreactivity tended to be inversely correlated with the clinical efficacy of the IC blockade therapy. In vitro studies revealed that 11βHSD1 promoted the intratumoural synthesis of cortisol. This resulted in a decrease in cytokines and in the inhibition of monocyte migration.

Conclusions

Our study is the first report clarifying the inhibitory effects of intratumourally synthesised cortisol through 11βHSD1 on immune cell migration. We propose that the response to IC blockade therapy in NSCLC may be predicted by 11βHSD1.

Cervical cancer screening rates before and after the Great East Japan Earthquake in the Miyagi Prefecture, Japan

After disasters, issues pertaining to women’s health such as irregular periods and bleeding are well surveyed. However, the management of women’s health, especially changes in the rate of health checkups, has not been investigated. In the present study, we focused on the change in the cervical cancer screening rates (CCS-Rs) before and after the Great East Japan Earthquake in Miyagi Prefecture, Japan. The earthquake had a magnitude of 9.0, a profound disaster. We examined the CCS-R from 2009 to 2016 in 45 areas of the Miyagi Prefecture. Screening was completed using mobile vans. In the 4 areas impacted by the tsunami after the earthquake, a marked decrease in the CCS-R was observed in 2011 when the earthquake took place (more than a 3% decrease compared with that in the previous year). The CCS-Rs in these 4 regions remained lower in 2016 than in the previous year. In 2009–2016 except for 2014, CCS-Rs in coastal areas (9 areas) were significantly lower than those in the non-coastal areas (36 areas). A delay in seeking healthcare, also known as “patient’s delay,” is considered as one of the problems of cancer treatment in affected areas. It is possible that a decrease in the CCS-R may lead to low detection of advanced stages of cancer. Therefore, the establishment of a comprehensive medical system including medical screening after a disaster is important for the management of women’s health.

Significance of glucocorticoid signaling in triple-negative breast cancer patients: a newly revealed interaction with androgen signaling

PURPOSE

Chemotherapy is the only current effective systemic treatment for triple-negative breast cancer (TNBC) patients. Therefore, the identification of active biological pathways that could become therapeutic targets is crucial. In this study, considering the well-reported biological roles of glucocorticoid and androgen receptors (GR, AR) in TNBC, we attempted to explore the effects of glucocorticoids (GCs) on cell kinetics as well as the potential interaction between GR and AR in TNBC.

METHODS

We first explored the association between the status of GR, AR, and/or GCs-metabolizing enzymes such as 11β-hydroxysteroid dehydrogenase (11βHSD) 1 and 2 and the clinicopathological variables of the TNBC patients. Thereafter, we also studied the effects of dexamethasone (DEX) with/without dihydrotestosterone (DHT) on TNBC cell lines by assessing the cell proliferation, migration and GC response genes at the transcriptional level.

RESULTS

GR positivity in carcinoma cells was significantly associated with adverse clinical outcome of the patients and AR positivity was significantly associated with lower histological grade and Ki-67 labeling index of the cases examined. In particular, AR positivity was significantly associated with decreased risks of developing recurrence in GR-positive TNBC patients. The subsequent in vitro studies revealed that DEX-promoted cell migration was inhibited by the co-treatment with DHT in GR/AR double-positive HCC38 cells. In addition, DHT inhibited the DEX-increased serum and glucocorticoid-regulated kinase-1 (SGK1) mRNA expression.

CONCLUSION

This is the first study to reveal that the interaction of GR and AR did influence the clinical outcome of TNBC patients and GCs induced cell migration in TNBC cells.