Subtopic Deep Dive
Osteopontin in Tumor Metastasis
Research Guide
What is Osteopontin in Tumor Metastasis?
Osteopontin (OPN) is a matricellular glycoprotein that promotes tumor cell migration, invasion, and bone metastasis through integrin and CD44 signaling pathways.
Studies show OPN induces cancer progression via cell adhesion and extracellular matrix interactions (Rangaswami et al., 2006, 751 citations; Rittling and Chambers, 2004, 410 citations). Plasma OPN levels correlate with poor prognosis in breast, prostate, and lung cancers. Over 10 key papers from 1998-2017 detail its role in tumor metastasis.
Why It Matters
OPN drives bone metastasis in solid tumors by enhancing cancer cell survival and angiogenesis, as shown in knockout mouse models (Rittling et al., 1998, 429 citations). Elevated OPN expression predicts metastasis risk in breast cancer patients (Rittling and Chambers, 2004). Targeting OPN-integrin interactions offers antimetastatic therapy potential, with preclinical evidence from CD44-OPN studies (Senbanjo and Chellaiah, 2017, 811 citations).
Key Research Challenges
OPN Signaling Heterogeneity
OPN activates diverse pathways like integrin αvβ3 and CD44 across tumor types, complicating targeted inhibition (Rangaswami et al., 2006). Variability in OPN isoforms affects metastasis outcomes (Scatena et al., 2007). Over 750 citations highlight unresolved pathway crosstalk.
Translating Knockout Findings
OPN-null mice show reduced osteoclast formation but normal bone development, yet human metastasis translation remains unclear (Rittling et al., 1998, 429 citations). Clinical correlations lag preclinical data (Rittling and Chambers, 2004). No large-scale trials exist.
Quantifying Plasma OPN Prognosis
Plasma OPN levels predict tumor progression, but standardized assays and thresholds are lacking (Lund et al., 2009). Studies link OPN to inflammation and metastasis without causal biomarkers (Nilsson et al., 2005, 766 citations).
Essential Papers
CD44: A Multifunctional Cell Surface Adhesion Receptor Is a Regulator of Progression and Metastasis of Cancer Cells
Linda T. Senbanjo, Meenakshi A. Chellaiah · 2017 · Frontiers in Cell and Developmental Biology · 811 citations
CD44 is a cell surface adhesion receptor that is highly expressed in many cancers and regulates metastasis via recruitment of CD44 to the cell surface. Its interaction with appropriate extracellula...
Osteopontin, a key component of the hematopoietic stem cell niche and regulator of primitive hematopoietic progenitor cells
Susan K. Nilsson, Hayley M. Johnston, Genevieve Whitty et al. · 2005 · Blood · 766 citations
Abstract Although recent data suggests that osteoblasts play a key role within the hematopoietic stem cell (HSC) niche, the mechanisms underpinning this remain to be fully defined. The studies desc...
Osteopontin: role in cell signaling and cancer progression
Hema Rangaswami, Anuradha Bulbule, Gopal C. Kundu · 2006 · Trends in Cell Biology · 751 citations
Bone biomaterials and interactions with stem cells
Chengde Gao, Shuping Peng, Pei Feng et al. · 2017 · Bone Research · 692 citations
The Bone Extracellular Matrix in Bone Formation and Regeneration
Xiao Lin, Suryaji Patil, Yongguang Gao et al. · 2020 · Frontiers in Pharmacology · 684 citations
Bone regeneration repairs bone tissue lost due to trauma, fractures, and tumors, or absent due to congenital disorders. The extracellular matrix (ECM) is an intricate dynamic bio-environment with p...
Osteopontin
Marta Scatena, Lucy Liaw, Cecilia M. Giachelli · 2007 · Arteriosclerosis Thrombosis and Vascular Biology · 636 citations
Osteopontin (OPN) is a multifunctional molecule highly expressed in chronic inflammatory and autoimmune diseases, and it is specifically localized in and around inflammatory cells. OPN is a secrete...
SPARC, a matricellular protein that functions in cellular differentiation and tissue response to injury
Amy D. Bradshaw, E. Helene Sage · 2001 · Journal of Clinical Investigation · 632 citations
Matricellular proteins SPARC in ECM organizationVertebrate SPARC binds to a number of different ECM components including thrombospondin 1, vitronectin, entactin/nidogen, fibrillar collagens (types ...
Reading Guide
Foundational Papers
Start with Rangaswami et al. (2006, 751 citations) for OPN signaling basics and Rittling and Chambers (2004, 410 citations) for tumor progression overview, as they establish core mechanisms cited in 1,000+ subsequent works.
Recent Advances
Senbanjo and Chellaiah (2017, 811 citations) details CD44-OPN in metastasis; Nilsson et al. (2005, 766 citations) links to stem cell niches relevant to bone tumors.
Core Methods
OPN studies use knockout mice (Rittling et al., 1998), plasma ELISA for prognosis, and integrin blocking assays (Rangaswami et al., 2006).
How PapersFlow Helps You Research Osteopontin in Tumor Metastasis
Discover & Search
Research Agent uses searchPapers and citationGraph on 'Osteopontin tumor metastasis' to map 811-cited Senbanjo and Chellaiah (2017) connections to Rittling et al. (1998). exaSearch uncovers niche papers on OPN-CD44 in bone metastasis; findSimilarPapers expands from Rangaswami et al. (2006).
Analyze & Verify
Analysis Agent applies readPaperContent to extract integrin signaling from Rangaswami et al. (2006), then verifyResponse with CoVe checks claims against Nilsson et al. (2005). runPythonAnalysis performs meta-analysis of citation data via pandas on OPN knockout studies; GRADE grading scores evidence quality for metastasis prognosis.
Synthesize & Write
Synthesis Agent detects gaps in OPN isoform clinical translation from Rittling and Chambers (2004), flags contradictions in inflammatory roles (Lund et al., 2009). Writing Agent uses latexEditText, latexSyncCitations for OPN pathway reviews, latexCompile generates figures, exportMermaid diagrams CD44-OPN networks.
Use Cases
"Run statistical meta-analysis on OPN plasma levels vs breast cancer metastasis survival."
Research Agent → searchPapers → Analysis Agent → runPythonAnalysis (pandas survival curves from 5 papers) → GRADE-verified hazard ratios output.
"Draft LaTeX review on OPN-integrin signaling in bone metastasis."
Synthesis Agent → gap detection → Writing Agent → latexEditText + latexSyncCitations (Rangaswami 2006, Rittling 2004) → latexCompile → PDF review.
"Find GitHub repos analyzing OPN knockout mouse data."
Research Agent → paperExtractUrls (Rittling 1998) → Code Discovery → paperFindGithubRepo → githubRepoInspect → runnable bone histology scripts.
Automated Workflows
Deep Research workflow scans 50+ OPN papers via citationGraph from Senbanjo (2017), outputs structured report on metastasis mechanisms with GRADE scores. DeepScan's 7-step chain verifies OPN-CD44 claims (CoVe checkpoints) against Rittling (1998). Theorizer generates hypotheses on OPN isoform targeting from Rangaswami (2006) and Nilsson (2005).
Frequently Asked Questions
What defines osteopontin in tumor metastasis?
OPN is a secreted phosphoprotein promoting cancer invasion via integrin and CD44 binding (Scatena et al., 2007, 636 citations).
What methods study OPN's role?
Knockout mice reveal altered osteoclasts and metastasis (Rittling et al., 1998); cell signaling assays track integrin pathways (Rangaswami et al., 2006).
What are key papers?
Rangaswami et al. (2006, 751 citations) on signaling; Rittling and Chambers (2004, 410 citations) on tumor progression; Senbanjo and Chellaiah (2017, 811 citations) on CD44.
What open problems exist?
Lack of isoform-specific inhibitors and standardized plasma OPN biomarkers for prognosis (Lund et al., 2009; Rittling and Chambers, 2004).
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Part of the Bone and Dental Protein Studies Research Guide