Biology subjects

Kremer, R.

Publications and source records attributed to Kremer, R..

7 recordsLinked to original sources

bioRxiv2026

Vitamin D counters bone invasion by mammary cancer through inhibition of inflammation and epithelial-to-mesenchymal transition

Vitamin D deficiency is associated with poor outcome in several cancers in humans, and administration of vitamin D or analogs has been shown to decrease tumor progression and metastasis in animal mammary cancer models. We previously demonstrated significant acceleration of carcinogenesis in vitamin D-deficient mouse mammary tumor virus-polyoma middle T (MMTV-PyMT) mammary cancer model as well as of its spontaneous metastasis to lungs. While vitamin D also plays a role in skeletal metastasis, detailed mechanisms of its promotion of bone invasion and metastatic events are not completely elucidated. In the present study we used tibially-injected MMTV-PyMT mammary tumor cells to analyse how dietary-induced vitamin D deficiency in non-immunodeficient FVB mice accelerates bone invasion. Mechanistically, we observed vitamin D deficiency to increase pro-inflammation cytokines and nestin expression in internal bone surface and marrow, and to increase epithelial-to-mesenchymal transition (EMT) through Zeb1 transcription factor. In vitro, treatment of MMTV-PyMT tumor cells with CXCL12 was observed to stimulate Zeb1 expression, and this effect was efficiently countered by 1,25(OH)2D treatment. Analysis of cytokines in MMTV-PyMT mammary tumor cells in vitro showed significant reduction in several pro-inflammatory cytokines with 1,25(OH)2D treatment (GM-CSF, ICAM-1, IL-1ra, IP-10, JE, MCP-5, MIP-1, MIP-1{beta}, MIP-2, RANTES and CXCL12), a crucial observation in view of the current evidence that inflammation is one of the hallmarks of cancer. Furthermore, vitamin D repleteness is associated with very high expression of Socs1 (suppressor of cytokine signalling 1), an inhibitor of JAK/STAT pathway which prevents excessive inflammatory responses and has a tumor-suppressive role. These findings provide a strong link between vitamin D deficiency and acceleration of inflammation-driven bone invasion, and nestin and EMT. The evidence suggests that vitamin D-repleteness in breast cancer patients could enhance the efficacy of co-administered therapies in preventing invasion of skeletal sites.

cancer biology↗

bioRxiv2026

LINC00536 regulates transcriptional repressor TRPS1 in breast cancer

Metastatic breast cancer with complex molecular mechanisms of progression accounts for most cancer related deaths in women. To improve diagnosis and drug development, it is important to identify novel biomarkers and critical molecular pathways involved in tumor initiation and progression. Here, we profiled and analyzed the expression of long non-coding RNAs (lncRNAs) from three distinct stages of tumor initiation and progression (hyperplasia, adenoma, and carcinoma). We performed RNAseq on tumor and mammary epithelial cells derived from ROSAmT/mG tumor and non-tumor mice. We identified 1913 differentially expressed protein coding genes and 324 lncRNAs in breast cancer cells of all stages compared with normal mammary epithelial cells. Pearson correlation analysis correlated 93 differentially expressed lncRNAs with protein coding genes, providing a comprehensive lncRNA-protein coding genes co-expression network. Among them, we focused on Gm19303 which was paired with the differentially expressed protein coding gene, transcriptional repressor GATA binding 1 (Trps1), and identified its human counterpart as LINC00536. Both LINC00536 and TRPS1 are only overexpressed in breast cancer and correlate with poor prognosis of patient from the TCGA and GTEx databases. Single cell RNAseq data from the Atlas of Human breast cancers further confirmed that TRPS1 is upregulated in human breast cancer compared to normal human mammary tissue with highest expression in ER+ subgroup. In summary, our study explored the potential role of lncRNAs in breast cancer initiation and progression. *Implications statement: Our findings imply that human LINC00536/TRPS1 serves as a novel and early biomarker of cancer progression and a potential therapeutic target for breast cancer.

cancer biology↗

bioRxiv2026

Mass spectrometry imaging shows specific lipids signals linked to Cyp27b1 ablation in the MMTV PyMT breast cancer model

Bioactive vitamin D (1,25-dihydoxyvitamin D or 1,25(OH)2D) is synthesized from its inert circulating form 25-hydroxyvitamin D (25(OH)D) by the enzyme 1--hydroxylase in the kidneys and in other tissues including breast. Because breast cancer is associated with changes in intra-tumoral lipid composition and vitamin D is known to affect lipid metabolism, we investigated the potential role of tumor-produced 1,25(OH)2D on lipid profile expression during breast tumor progression. For that purpose, we used the MMTV-PyMT mouse model which mimics the four phases of tumor progression seen in human breast cancer (hyperplasia, adenoma/mammary intraepithelial neoplasia (MIN), early carcinoma and late carcinoma). In previous studies we showed that conditional ablation of the gene encoding 1--hydroxylase (Cyp27b1), specifically in the mammary epithelium of this MMTV-PyMT mouse model, resulted in enhanced spontaneous tumor initiation and progression. In the present study, we used mass spectrometry imaging to compare lipid composition in the mammary glands of Cyp27b1 ablated and non-ablated MMTV-PyMT mice. In non-ablated control animals, we observed changes to specific lipid signals linked to stages of tumor progression. In particular, several discriminatory lipid signals were significantly up regulated throughout tumor progression. In ablated mice, absence of Cyp27b1 in the mammary epithelium was accompanied by different lipid signals in hyperplastic lesions. Several lipid signals were exclusively detected in non-ablated tumors but absent in hyperplasia. Our findings suggest that the tumor-produced 1,25(OH)2D known to play a key role in mammary tumor progression is mechanistically related to early changes in lipid composition seen prior to the development of hyperplasia.

cancer biology↗

bioRxiv2025

Pancreatic cancer cachexia is mediated by PTHrP-driven disruption of adipose de novo lipogenesis

Pancreatic cancer patients have the highest rates and most severe forms of cancer cachexia, yet cachexia etiologies remain largely elusive, leading to a lack of effective intervening therapies. Parathyroid hormone-related protein (PTHrP) has been clinically implicated as a putative regulator of cachexia, with serum PTHrP levels correlating with increased weight loss in PDAC patients. Here we show that cachectic PDAC patients have high expression of tumor PTHrP and use a genetically engineered mouse model to functionally demonstrate that loss of PTHrP blocks cachectic wasting, dramatically extending overall survival. The re-expression of PTHrP in lowly cachectic models is sufficient to induce wasting and reduce survival in mice, which is reversed by the conditional deletion of the PTHrP receptor, Pth1r, in adipocytes. Mechanistically, tumor-derived PTHrP suppresses de novo lipogenesis in adipocytes, leading to a molecular rewiring of adipose depots to promote wasting in the cachectic state. Finally, the pharmacological disruption of the PTHrP-PTH1R signaling axis abrogates wasting, highlighting that a targeted disruption of tumor-adipose crosstalk is an effective means to limit cachexia. STATEMENT OF SIGNIFICANCEPancreatic ductal adenocarcinoma (PDAC) is the prototypical cancer type associated with cancer cachexia, a debilitating wasting syndrome marked by adipose tissue loss and muscle atrophy. Herein, we establish that PTHrP is a tumor-derived factor that facilitates cachexia by downregulating de novo lipogenesis in adipocytes and that blocking PTHrP is an effective means to limit wasting in preclinical mouse models.

cancer biology↗

bioRxiv2024

The identification of a SARs-CoV2 S1 protein derived peptide with super-antigen-like stimulatory properties on T-cells

Severe COVID-19 can trigger a cytokine storm, leading to acute respiratory distress syndrome (ARDS) with similarities to superantigen-induced toxic shock syndrome. An outstanding question is whether SARS-CoV-2 protein sequences can directly induce inflammatory responses. In this study, we identify a region in the SARS-CoV-2 S2 spike protein with sequence homology to bacterial super-antigens (termed P3). Computational modeling predicts P3 binding to sites on MHC class I/II and the TCR that partially overlap with sites for the binding of staphylococcal enterotoxins B and H. Like SEB and SEH peptides, P3 stimulated 25-40% of human CD4+ and CD8+ T cells, increasing IFN-{gamma} and granzyme B production. viSNE and SPADE profiling identified overlapping and distinct IFN-{gamma} and GZMB subsets. The super-antigenic properties of P3 were further evident by its selective expansion of T cells expressing specific TCR V and V{beta} chain repertoires. In vivo experiments in mice revealed that the administration of P3 led to a significant upregulation of proinflammatory cytokines IL-1{beta}, IL-6, and TNF-. While the clinical significance of P3 in COVID-19 remains unclear, its homology to other mammalian proteins suggests a potential role for this peptide family in human inflammation and autoimmunity.

immunology↗

bioRxiv2024

Anti-PTHrP blockade limits CD8+ T-cell exhaustion in anti-cancer immunotherapy

Cancer is a major global health concern, with immune suppression hindering treatment. Immunotherapy, specifically immune checkpoint blockage on T cells, has revolutionized cancer treatment. T-cell exhaustion is an abnormal activation state that develops when continuous exposure to antigens, like cancer. In this context, recent evidence suggests that parathyroid hormone-related protein (PTHrP) plays a previously underappreciated role in fostering an immunosuppressive tumor microenvironment. Further, blocking PTHrP activity reduces primary tumor growth, prevents metastasis, and prolongs survival in mice with various cancers. Here, we confirm that administration of anti-PTHrP monoclonal antibodies can reduce the growth of B16-PDL1 melanoma tumors and that although the therapy did not alter the presence of CD4+ and CD8+ TILs, we noted that all stages of T-cell exhaustion were reduced. Further, the expression of cytolytic proteins PERFORIN and GZMB also increased. By contrast, anti-PTHrP therapy increased the relative presence of pre-pro B cells with a decline in mature B cells in the bone marrow. Overall, our data indicates that anti-PTHrP therapy acts by reducing T-cell exhaustion and by affecting B-cell development. These provide further mechanistic evidence to support the application of anti-PTHrP blockade as an alternate therapeutic approach to boost anti-tumor immunity.

immunology↗

bioRxiv2023

Improving the sensitivity of fluorescence-based immunoassays by time-resolved and spatial-resolved measurements

Detection of target molecules, such as proteins, antibodies, or specific DNA sequences, is critical in medical laboratory science. Commonly used assays rely on tagging the target molecules with fluorescent probes. These are then fed to high-sensitivity detection systems. Such systems typically consist of a photodetector or camera and use time-resolved measurements that require sophisticated and expensive optics. Magnetic modulation biosensing (MMB) is a novel, fast, and sensitive detection technology that has been used successfully to detect viruses such as Zika and SARS-CoV-2. While this powerful tool is known for its high analytical and clinical sensitivity, the current signal-processing method for detecting the target molecule and estimating its dose is based on time-resolved measurements only. To improve the MMB-system performance, we propose here a novel signal processing algorithm that uses both temporally and spatially resolved measurements. We show that this combination significantly improves the sensitivity of the MMB-based assay. To evaluate the new method statistically, we performed multiple dose responses of Human Interleukin 9 (IL -8) on different days. Compared to standard time-resolved methods, the new algorithm provides a 2-3 fold improvement in detection limit and a 25% improvement in quantitative resolution.

bioengineering↗