Biology subjects

Takamatsu, S.

Publications and source records attributed to Takamatsu, S..

11 recordsLinked to original sources

bioRxiv2026

Hypoxia reduces induced LRIG1 protein despite sustained mRNA induction in colorectal cancer organoids

LRIG1 is a negative regulator of receptor tyrosine kinase (RTK) signaling that promotes tumor suppression by driving degradation of EGFR and other RTKs. Inducing LRIG1 expression has therefore been proposed as a strategy to limit cancer cell survival under hypoxia. However, whether hypoxia itself affects LRIG1 expression remains unclear. Here, we investigated how hypoxia affects LRIG1 expression and protein abundance in human cancer datasets and colorectal cancer organoids. Analysis of The Cancer Genome Atlas data across gastrointestinal and other cancers revealed an inverse association between LRIG1 mRNA expression and a hypoxia gene signature that persisted after adjustment for global gene expression. We previously showed that BMPR inhibition induces LRIG1 and suppresses colorectal cancer organoid growth through LRIG1. Under hypoxia, this growth inhibition in colorectal cancer organoids was attenuated, and LRIG1 protein accumulation was reduced despite sustained mRNA induction. Pre-induced LRIG1 protein declined within 3 h of hypoxic exposure in organoids, and ectopically expressed LRIG1 similarly decreased in HEK293 cells. Pharmacological HIF1 inhibition did not prevent LRIG1 protein loss under hypoxia, whereas HIF1 stabilization did not reproduce it under normoxia, suggesting limited HIF1 involvement. Bafilomycin A1 restored LRIG1 protein levels, whereas chloroquine and the proteasome inhibitor MG132 did not, implicating a bafilomycin A1-sensitive lysosomal process. Notably, the hypoxia-induced decrease in LRIG1 was not accompanied by a decrease in total EGFR. These findings suggest that hypoxia limits LRIG1 protein induction, potentially constraining strategies that rely on LRIG1 induction in cancer treatment.

biochemistry↗

bioRxiv2026

Prohaptoglobin Promotes Pancreatic Cancer Progression by sustaining YAP Activity

Background & AimsProhaptoglobin (proHp), a precursor of haptoglobin (Hp), has recently emerged as a cancer-associated biomarker, but its functional role in pancreatic cancer remains unclear. We investigated whether proHp promotes malignant phenotypes of pancreatic cancer and explored signaling pathways involved. MethodsSerum proHp was examined in patients with pancreatic cancer and healthy controls. HP expression in pancreatic tumors and cell lines was analyzed using transcriptomic datasets. ProHp function was evaluated using PSN1 HP knockout (HPKO) cells, exogenous proHp supplementation, xenograft models, and RNA sequencing of PSN1 wild-type and HPKO cells. YAP activity was assessed by target gene expression, subcellular localization, YAP overexpression, and inhibition of YAP-TEAD interaction. ResultsSerum proHp was significantly elevated in patients with pancreatic cancer, and a subset of tumors and pancreatic cancer cell lines showed HP expression comparable to liver, indicating a tumor-derived source of proHp. In PSN1 cells, HPKO reduced motility, whereas exogenous proHp partially rescued this defect and enhanced motility in additional pancreatic cancer cell lines. Wild-type PSN1 cells continued to proliferate beyond confluence and formed rapidly growing xenograft tumors, which were abolished in HPKO cells. At high density, wild-type cells maintained YAP-related gene expression and nuclear YAP despite Hippo activation, whereas HPKO exhibited reduced nuclear YAP, indicating noncanonical YAP regulation by proHp. YAP restoration in HPKO cells rescued high-density proliferation and cell motility, while a YAP-TEAD inhibitor selectively reduced high-density proliferation of wild-type but not HPKO cells. ConclusionProHp promotes pancreatic cancer progression in a context-dependent manner by sustaining YAP activity and enabling cells to partially overcome contact-dependent growth inhibition. SynopsisProhaptoglobin, a precursor of haptoglobin, is elevated in pancreatic cancer and produced by tumor cells. It promotes cell motility, supports tumor growth under high-density conditions, and maintains YAP-dependent transcription that overrides contact-dependent growth inhibition. What You Need to Know BackgroundProhaptoglobin, a precursor of haptoglobin, is elevated in pancreatic cancer, but its tumor-derived origin and functional role are unknown. We examined whether prohaptoglobin drives progression by sustaining YAP signaling. ImpactWe show that tumor-derived prohaptoglobin sustains nuclear YAP activity, allowing pancreatic cancer cells to bypass contact inhibition and proliferate, revealing prohaptoglobin as a context-dependent driver rather than a passive biomarker. Future DirectionsDefining how prohaptoglobin engages upstream Hippo-YAP regulators and whether prohaptoglobin-YAP signaling is targetable in vivo may uncover new biomarkers and therapeutic vulnerabilities for pancreatic cancer.

cancer biology↗

bioRxiv2026

Enterococcus faecalis is involved in the progression of the early stages of latent chronic pancreatitis surrounding pancreatic cancer tissue

(Objective) In our previous research, we identified latent chronic pancreatitis in the normal tissue surrounding pancreatic cancer. We also discovered the presence of Enterococcus faecalis (E. faecalis), a type of intestinal bacterium, in the pancreatic fluid and tissue of pancreatic cancer patients, suggesting it may be one of the factors contributing to the development of latent chronic pancreatitis. In this study, we performed pathological analyses to investigate its characteristics and investigate a possibility of E. faecalis infection. (Methods) Pathological analyses were performed, using 16 cases of pancreatic cancer and intraductal papillary mucinous neoplasia (IPMN) involving lesions in the pancreas tail. The involvement of E. faecalis was investigated with immunohistochemical analysis and serological methods. (Results) All cases exhibited inflammatory changes in pancreatic tissue without a clinical diagnosis of chronic pancreatitis, along with macrophage infiltration. These changes did not significantly differ according to preoperative treatment. DNA encoding E. faecalis 16s ribosomal RNA was detected in many cases, however, a positive immunostaining to E. faecalis was observed in only a few cases. Serum capsular polysaccharide (CPS) antibody levels exceeding the mean values were observed in patients with established chronic pancreatitis, while the level was not correlated with E. faecalis immunostaining. (Conclusion) These results suggest the E. faecalis infection is involved in the early stage of the progression of chronic latent pancreatitis and the diagnostic technology incorporating novel multi-biomarkers may be useful for identifying high-risk individuals for future pancreatic cancer development.

cancer biology↗

bioRxiv2026

FUT8 mediated core fucosylation modulates growth related functions of LRP1 in liver cancer cells

Fucosylation is a cancer-associated glycosylation change, and core fucosylation of N-glycans catalyzed by the 1,6-fucosyltransferase FUT8, has been closely linked to tumor progression, metastasis, drug resistance, and poor prognosis. However, the core-fucosylated proteins that directly support hepatocarcinogenesis are not fully defined. In a KRAS-G12D-driven mouse liver cancer model, we observed increased fucosylation and FUT8 upregulation, and glycoproteomic analysis of fucose-enriched fractions identified low-density lipoprotein receptor-related protein 1 (LRP1) as a prominent core-fucosylated protein in tumor tissue. In immortalized mouse hepatocytes, genetic or pharmacological inhibition of FUT8 markedly increased Lrp1 mRNA and protein, indicating that loss of core fucosylation is accompanied by robust upregulation of LRP1. In human HepG2 cells, LRP1 knockout suppressed cell proliferation and markedly altered colony morphology, leading to compact rounded clusters instead of the typical polygonal pattern. It also reduced EGFR protein and further inhibited proliferation of HepG2 cell. These findings identify LRP1 as a FUT8-dependent core-fucosylated receptor in experimental hepatocarcinogenesis and suggest that the FUT8-LRP1 axis contributes to the maintenance of proliferative signaling in hepatoma cells.

cancer biology↗

bioRxiv2025

Targeted suppression of SPP1 inhibits tumor invasion and metastasis in NRF2 hyperactivated cisplatin resistant HNSCC

PurposeCisplatin is the gold standard systemic agent for definitive treatment of HNSCC. The purpose of this study was to investigate the role of SPP1 in the progression and metastasis of cisplatin-resistant HNSCC, particularly in the context of NRF2 hyperactivation. Experimental DesignCDDP resistant HNSCC cell lines stably expressing various shRNA SPP1 constructs were generated. Clonogenic survival assays and a mouse model of oral cancer were used to examine the impact of silenced SPP1 in vitro and in vivo on CDDP sensitivity and tumor progression. Western blotting, cell invasion, functional proteomics RPPA and spatial transcriptomic analyses were performed to identify molecular interactions and metastatic signaling pathways. ResultsTargeted suppression of SPP1 improved cisplatin sensitivity, inhibited tumor invasion and metastasis in vitro and in vivo as well as several metastatic signaling proteins in NRF2- hyperactivated HNSCC. Spatial transcriptomic analysis revealed a potential mechanistic interaction between SPP1, integrins and CD44 receptors in primary and metastatic HNSCC. Spatial annotation and enrichment analyses using HALLMARK revealed gene set signatures of interferon and EMT present in cell clusters with SPP1 expression in both the primary tumor and lung metastases. Finally, increased expression of SPP1 was found to be poor prognostic factor and significantly correlated with NFE2L2/KEAP1 mutational status and higher tumor grade in HNSCC patients. ConclusionsTargeting dysregulated SPP1 improved cisplatin sensitivity, inhibited tumor invasion and metastasis in NRF2-hyperactivated HNSCC. These findings highlight the therapeutic potential of targeting SPP1 and the need for developing specific SPP1 inhibitors to improve outcomes for patients with HNSCC. Translational RelevanceCisplatin-based chemotherapy remains the standard of care for patients with locally advanced head and neck squamous cell carcinoma. Cisplatin resistance often leads to treatment failure and metastasis which accounts for the majority of mortality associated with this disease. Unfortunately, there are no effective therapeutic agents to overcome cisplatin resistance in HNSCC. Here, we present compelling evidence that targeting SPP1 (also known as osteopontin) inhibits cisplatin resistance, tumor progression and metastasis in NRF2-hyperactivated HNSCC, positioning it as a potential therapeutic target to improve treatment outcomes in HNSCC.

cancer biology↗

bioRxiv2025

Functional Impact of Glycosylation and Splicing Variants of LRIG1 on EGFR Proteostasis in Cancer

LRIG1, a membrane glycoprotein, has emerged as a significant stem cell marker and negative regulator of receptor tyrosine kinases (RTKs), including EGFR. Glycosylation is a major post-translational modification, which plays a crucial role in protein function and stability. In cancer biology, abnormal glycosylation can serve as a biomarker and contribute to pathogenesis. We aimed to investigate the effects of glycosylation on LRIG1 functions. Through database analysis and experimental approaches, we focused on evolutionarily conserved glycosylation sites of LRIG1, particularly N74 in humans. We found that a mutation of the N74 glycosylation site (N74Q) enhances LRIG1s binding to EGFR and promotes EGFR degradation. Furthermore, we identified a naturally occurring splice variant of LRIG1 lacking exon 2, which includes the N74 site, that shows similar enhanced EGFR binding and degradation. Analysis of TCGA data revealed that exon 2 skipping in LRIG1 occurs in various cancers, with higher levels correlating with poorer survival in breast and ovarian cancers. Our findings suggest that the absence of glycosylation at N74 enhances LRIG1-EGFR binding, providing an example of glycosylation negatively regulating protein-protein interaction. This mechanism, achieved through alternative splicing, provides insights into the importance of glycosylation deficiency in cancer biology.

biochemistry↗

bioRxiv2023

Homologous recombination deficiency in cell line libraries does not correlate with in vitro sensitivity to platinum agents or PARP inhibitors

Although preclinical studies for drug discovery and biomarker development are extensively conducted using large publicly available cancer cell line databases, there have been no reports to date that clarify the association between homologous recombination repair deficiency (HRD) and drug sensitivity using these data. We comprehensively analyzed the molecular profiles and drug response screening data from the Cancer Cell Line Encyclopedia. Unexpectedly, gene alterations in BRCA1/2 or homologous recombination repair-related genes, HRD score, or mutational signature 3 were not significantly correlated with sensitivity to platinum agents or PARP inhibitors. Rather, higher HRD scores and mutational signature 3 were significantly associated with resistance to platinum and PARP inhibitors in multiple assays. These findings were consistent when analyses were restricted to breast and ovarian cancer cell lines and when data from the COSMIC Cell Line Project dataset were used. SignificanceIn existing cancer cell line databases, the association between HRD status and sensitivity to platinum or PARP inhibitors differs from that expected from clinical tumor data. This discrepancy may also apply to other tumor characteristics, and researchers should be aware of the potential limitations of cell line data. Structural abstractO_ST_ABSBackgroundC_ST_ABSComprehensive molecular profiling and drug sensitivity screening data from over 1000 cancer cell lines are currently available for preclinical studies including targeted drug discovery and biomarker development. However, there are no reports using these cell line databases to clarify the association between homologous recombination repair deficiency (HRD) and drug sensitivity. MethodsWe investigated the association between HRD status, including gene alterations in the homologous recombination repair (HR) pathway, HRD score, and mutational signature 3, and sensitivity to platinum agents and PARP inhibitors in the Cancer Cell Line Encyclopedia (CCLE) and the COSMIC Cell Line Project (CLP) datasets. ResultsIn the CCLE dataset (n=1182), samples with BRCA alterations, including BRCA1 methylation and BRCA1/2 mutations with locus-specific loss-of-heterozygosity, exhibited higher HRD scores and mutational signature 3. These two scores were positively correlated (r=0.475, p=1.25 x10-52). Unexpectedly, neither BRCA1/2 nor HR-related gene alterations correlated with sensitivity to platinum agents or PARP inhibitors. Instead, significantly positive correlations were observed between drug-response AUC values and HRD scores in 60% (6/10) of platinum agent assays, and in 43% (6/14) PARP inhibitor assays, while no significant negative correlation was observed. Similar results were obtained in the analysis with mutational signature 3. These findings were consistent in analyses limited to ovarian and breast cancer cell lines and in the CLP dataset, indicating samples with HRD showed resistance rather than sensitivity to these drugs. ConclusionIn existing cancer cell line databases, the association between HRD status and sensitivity to platinum and PARP inhibitors differs from that expected from clinical tumor data. This discrepancy may also apply to other tumor characteristics, and investigators should be aware of the potential limitations of cell line data.

cancer biology↗

bioRxiv2021

Tertiary lymphoid structures induced by CXCL13-producing CD4+ T cells increase tumor infiltrating CD8+ T cells and B cells in ovarian cancer

BackgroundTertiary lymphoid structures (TLSs) are transient ectopic lymphoid aggregates whose formation might be caused by chronic inflammation states, such as cancer. The presence of TLS is associated with a favorable prognosis in most solid malignancies. The recognition of the relevance of TLS to cancer has led to a growing interest in TLS as an immunomodulatory target to enhance tumor immunity, although how TLSs are induced in the tumor microenvironment (TME) and how they affect patient survival are not well understood. MethodsTLS distribution in relation to tumor infiltrating lymphocytes (TILs) and related gene expression were investigated in high grade serous ovarian cancer (HGSC) specimens. CXCL13 expression, which is strongly associated with TLS, and its localization in immune cells, were examined. We explored the tumor microenvironment for CXCL13 secretion by adding various inflammatory cytokines in vitro. The induction of TLS by CXCL13 was examined in a mouse model of ovarian cancer. ResultsCXCL13 gene expression correlated with TLS formation and the infiltration of T cells and B cells, and was a favorable prognostic factor for HGSC patients. The coexistence of CD8+ T cells and B-cell lineages in the TME was associated with a better prognosis of HGSC and was closely related to the presence of TLSs. CXCL13 expression was predominantly coincident with CD4+ T cells in TLSs and CD8+ T cells in TILs, and shifted from CD4+ T cells to CD21+ follicular dendritic cells as the TLS matured. Although TGF-{beta} was reported to stimulate CXCL13 production, our in vitro results revealed that CXCL13 secretion was promoted in CD4+ T cells under TGF-{beta} + IL-2-restricted conditions and in CD8+ T cells under TGF-{beta} + IL-12-rich conditions. In a mouse model of ovarian cancer, recombinant CXCL13 induced TLSs and enhanced survival by the infiltration of CD8+ T cells. ConclusionsTLS formation was promoted by CXCL13-producing CD4+ T cells and TLSs facilitated the coordinated antitumor responses of cellular and humoral immunity in ovarian cancer.

immunology↗

bioRxiv2021

Enterococcus spp. have higher fitness for survival, in a pH-dependent manner, in pancreatic juice among duodenal bacterial flora

ObjectivesBacterial infection is involved in the progression of many gastrointestinal diseases, including cancer; however, how and which bacteria colonize in pancreatic juice and tissue have yet to be elucidated. Recently, we reported that Enterococcus faecalis exists in the pancreatic juice and tissues of patients with chronic pancreatic disease. Here, we investigated the survival of E. faecalis in duodenal juice with different pH conditions. MethodsPancreatic juice samples from 62 patients with cancers of the duodeno-pancreato-biliary region were evaluated for the presence of E. faecalis. 16S ribosomal RNA PCR and 16S-based metagenome analyses were performed to determine the bacterial composition. The survival of E. faecalis in various pancreatic juice conditions was evaluated. ResultsOf 62 samples, 27% (17/62) were positive for Enterococcus spp., among which 71% (12/17) contained E. faecalis. Enterococcus spp. showed the highest fitness for survival in alkaline pancreatic juice among various bacterial species. The microbiome of pancreatic juice from patients with pancreatic and bile duct cancer showed diversity, but Enterococcus spp. were enriched among duodenal tumors and intraductal papillary mucinous neoplasms. ConclusionsAlkalinity is important for the selective survival of E. faecalis among microbiota. E. faecalis may induce pancreatic inflammation with changes in pancreatic juice conditions.

microbiology↗

bioRxiv2020

Ion mechanism and parameter analysis of anodal-first waveforms for selective stimulation of C-fiber nerves

Few investigations have been conducted on selective stimulation of small-radius unmyelinated C nerves (C), which is critical to both recoveries of damaged nerves and pain suppressions. The purpose of this study is to understand how an anodal pulse in an anodal-first stimulation could improve C-selectivity over myelinated nociceptive A{delta} nerves (A{delta}), and further clarify the landscape of the solution space. The Hodgkin-Huxley (HH) model and the Mclntyre-Richardson-Grill (MRG) model were used for modelling C and A{delta}, respectively to analyze the underlying ion dynamics and the influence of relevant stimulation waveforms, including monopolar, polarity-symmetric, and asymmetric pulses. Results showed that polarity-asymmetric waveforms with preceding anodal stimulations benefit C-selectivity most, underlain by the decrease of the potassium ion current of C. The optimal parameters for C-selectivity have been identified in the low frequency band, which will benefit remarkably the designs of nociceptive nerve selective stimulation.

neuroscience↗

bioRxiv2018

Gene erosion and genome expansion in a group of highly host-specialized fungal phytopathogens

Due to their comparatively small genome size and short generation time, fungi are exquisite model systems to study eukaryotic genome evolution. Powdery mildew (PM) fungi present an exceptional case where their strict host dependency (a lifestyle termed obligate biotrophy) is associated with some of the largest fungal genomes sequenced so far (>100 Mbp). This size expansion is largely due to the pervasiveness of transposable elements (TEs), which can cover more than 70% of these genomes, and is associated with the loss of multiple conserved ascomycete genes (CAGs) required for a free-living lifestyle. To date, little is known about the mechanisms that drove this expansion, and information on ancestral PM genomes is lacking. We report the genome analysis of the early-diverged PM species Parauncinula polyspora that in contrast to most other PMs reproduces exclusively sexually. The P. polyspora genome is surprisingly small (<30 Mb) and sparsely equipped with TEs (<10%), despite the conserved absence of a common defense mechanism (RIP) involved in constraining repetitive elements. The genome still harbors the majority of the CAGs that are absent in the genomes of the recently evolved PMs. We speculate that TE spread might have been limited by its unique reproduction strategy and host features and further hypothesize that the loss of CAGs may promote the evolutionary isolation and host niche specialization of PM fungi. Limitations associated with this evolutionary trajectory might have been in part counteracted by the evolution of plastic, TE-rich genomes and/or the expansion of gene families encoding secreted virulence proteins.

genomics↗