PTHLH

PTHLH Full Name

parathyroid hormone-like hormone

PTHLH Introduction

PTHLH, also known as the gene encoding parathyroid hormone-related protein (PTHrP), is a multifunctional regulatory molecule involved in tissue development, cellular differentiation, and disease-associated signaling. Located on chromosome 12, the PTHLH gene contains multiple promoters and alternative splicing mechanisms that generate several mRNA and protein isoforms with distinct biological activities. After translation, PTHrP can be processed into different functional peptide fragments, including N-terminal, mid-region, and C-terminal domains, each contributing to specific cellular responses. Most classical signaling occurs through binding to the PTH1R receptor, activating downstream cAMP/PKA and PLC/PKC pathways that regulate proliferation, survival, differentiation, and tissue remodeling. Unlike hormones restricted to endocrine tissues, PTHLH is broadly expressed in bone, cartilage, adipose tissue, skin, teeth, and other normal tissues, highlighting its importance in maintaining developmental and physiological homeostasis.

Growing evidence shows that abnormal PTHLH signaling is closely associated with non-tumoral diseases involving chronic inflammation, fibrosis, and impaired tissue regeneration. Studies have demonstrated that PTHrP plays an important role in osteogenic differentiation and mesenchymal stem cell regulation through interaction with the cAMP/PKA/CREB signaling axis. In craniofacial fibrous dysplasia-derived bone marrow mesenchymal stem cells, activation of cAMP signaling increased PTHrP expression, while inhibition of the CREB transcription factor significantly reduced its expression, confirming a reciprocal regulatory mechanism. These findings are particularly relevant for regenerative medicine and skeletal disease research, where controlling stem cell differentiation remains a major challenge. Beyond bone biology, dysregulated PTHLH expression has also been linked to liver fibrosis, pancreatitis, diabetes-associated tissue injury, and pathological remodeling processes, suggesting that PTHLH functions as an active mediator of disease progression rather than a passive biomarker.

In cancer biology, PTHLH has attracted increasing attention because of its ability to reshape the tumor microenvironment and suppress anti-tumor immunity. Recent studies using pancreatic cancer models showed that tumor-derived PTHrP promotes the recruitment of myeloid-derived suppressor cells (MDSCs) while reducing CD8+ T-cell infiltration, creating an immunosuppressive environment that supports tumor progression. Mechanistically, elevated PTHLH expression was associated with increased Cxcl1 signaling and reduced expression of immune-recruiting chemokines such as Cxcl10. Additional research in tongue squamous cell carcinoma demonstrated that genetic deletion of tumor-secreted PTHLH enhanced anti-tumor immune responses and altered neuroimmune signaling pathways involved in tumor innervation and immune regulation. High PTHLH expression has also been associated with poorer immunotherapy outcomes in several tumor models. These findings suggest that PTHLH is not only involved in tumor growth, but also acts as a key regulator of immune evasion, inflammatory signaling, and neuroimmune communication, making it a promising therapeutic target in cancer immunotherapy and tumor microenvironment-focused drug development.

Alternate Names for PTHLH

PTHLH; parathyroid hormone-like hormone; parathyroid hormone-related protein; HHM; osteostatin; PLP; PTHR; PTHRP; PTH-rP; PTH-related protein; parathyroid hormone-like related protein; BDE2; MGC14611;

• 1.Librizzi M, et al.; Parathyroid Hormone Related Protein (PTHrP)-Associated Molecular Signatures in Tissue Differentiation and Non-Tumoral Diseases. Biology (Basel). 2023, 12(7):950.
  2.Shen L, et al.; PTHrP Modulates the Proliferation and Osteogenic Differentiation of Craniofacial Fibrous Dysplasia-Derived BMSCs. Int J Mol Sci. 2023, 24(8):7616.