Biology subjects

Naqvi, S. M.

Publications and source records attributed to Naqvi, S. M..

4 recordsLinked to original sources

bioRxiv2025

Osteoblasts Exert a Pro-Tumorigenic Effect on Breast Cancer Spheroids Through CXCL5/CXCR2 Signaling In 2D And 3D Bone Mimetic Cultures

Bone provides a favorable niche for breast cancer colonization and metastatic progression. Breast cancer cells are attracted to the bone microenvironment where they induce bone cells to resorb bone, which enhances tumor cell proliferation in a positive feedback loop often referred to as the vicious cycle. While this phenomenon is established, the molecular interactions between cancer cells and bone cells are not well defined. CXCL5/CXCR2 signaling has recently been shown to promote breast cancer colonization to the bone. Here, we investigate the effects of osteoblasts and osteocytes on breast cancer cell proliferation in engineered two- and three-dimensional models. We observed that osteoblasts and osteocytes induce proliferative effects on cancer cells. Specifically, bone cells increase cancer proliferation in 2D culture and osteoblasts increase cancer growth more than osteocytes in 3D models. Moreover, osteocyte interaction with cancer cells in 3D models are stiffness dependent. We show that these effects depend on the CXCL5/CXCR2 signaling axis. Taken together, we demonstrate that osteoblasts drive cancer growth in a bone metastatic niche and that this effect can be rescued with CXCL5/CXCR2 inhibition.

bioengineering↗

bioRxiv2024

Estrogen Deficiency alters Vascularization and Mineralization dynamics: insight from a novel 3D Humanized and Vascularized Bone Organoid Model

Osteoporosis is not merely a disease of bone loss but also involves changes in the mineral composition of the bone that remains. In vitro studies have investigated these changes and revealed that estrogen deficiency alters osteoblast mineral deposition, osteocyte mechanosensitivity and osteocyte regulation of osteoclastogenesis. During healthy bone development, vascular cells stimulate bone mineralization via endochondral ossification, but estrogen deficiency impairs vascularization. Yet, existing in vitro bone models overlook the role of vascular cells in osteoporosis pathology. Thus, here we (1) develop an advanced 3D vascularized, mineralized and humanized bone model following the endochondral ossification process, and (2) apply this model to mimic postmenopausal estrogen withdrawal and provide a mechanistic understanding of changes in vascularization and bone mineralization in estrogen deficiency. We confirmed the successful development of a vascularized and mineralized human bone model via endochondral ossification, which induced self-organization of vasculature, associated with hypertrophy (collagen X), and promoted mineralization. When the model was applied to study estrogen deficiency, we reported the development of distinct vessel-like structures (CD31+) in the postmenopausal 3D constructs. Moreover, during estrogen withdrawal vascularized bone demonstrated a significant increase in mineral deposition and apoptosis, which did not occur in non-vascularized bone. These findings reveal a potential mechanism for bone mineral heterogeneity in osteoporotic bone, whereby vascularized bone becomes highly mineralized whereas in non-vascularised regions this effect is not observed. New and NoteworthyHere we develop an in vitro 3D vascularized and humanized bone model following an endochondral ossification approach. We applied the model to recapitulate estrogen deficiency as representative of osteoporotic phenotype. The results of this study reveal that estrogen deficiency exacerbates formation of 3D vessel like structures in vascularized models and thereby drives mineral deposition.

bioengineering↗

bioRxiv2024

Early Intervention with Low-Dose Sclerostin Antibody Therapy can Reduce Osteocyte-mediated Secondary Mineralization after initial bone loss in Ovariectomised Rats

Neutralizing sclerostin antibodies (Scl-Ab) mitigate bone loss and promote bone formation to address fracture risk in postmenopausal osteoporosis. Clinically, this treatment is administered monthly for women at high risk of fragility fractures, who are often years into menopause. Preclinical studies have demonstrated that dampening of bone formation occurs with continuous dosing at supraphysiological doses. Osteoporotic bone loss occurs rapidly during early menopause, followed by longer-term changes in bone mineralization and osteocyte activity. Whether earlier administration of lower-exposure Scl-Ab can mitigate bone loss and osteocyte-driven secondary mineralisation is unknown. The objective of this study was to evaluate the effects of early intermittent low-dose Scl-Abon: (1) osteoclastogenesis and bone resorption, (2) perilacunar remodelling, (3) secondary mineralization, and (4) osteocyte mechanosensitivity. Female retired breeder Wistar rats underwent bilateral ovariectomy and received monthly low-dose Scl-Ab injections (2 mg/kg/month) from 3 to 14 weeks post-OVX, while a control group remained untreated. Early intermittent low-dose Scl-Ab treatment increased bone formation and reduced osteoclastogenesis and catabolic gene expression ((Sost, Ctsk, Mmp9) compared to untreated rats. Treatment also decreased the percentage of empty lacunae and the number of MMP14+ osteocytes, accompanied by lower perilacunar mineral density and smaller lacunar size, indicating improved osteocyte survival and reduced perilacunar remodelling. Conversely, expression of osteocyte-mediated mineralization genes (DMP1, PHEX, OPN, ALP) and mechanotransduction-related genes (Vcl, integrins 5, V, {beta}1, CX43, Axin2, IFT88, Adcy6, Pkd1, Cav1) were reduced. Together, these findings suggest that early intermittent low-dose Scl-Ab therapy promotes surface bone formation while attenuating osteocyte-mediated secondary mineralization after initial bone loss. Mini AbstractEarly intermittent low-dose sclerostin antibody treatment reduced osteoclastogenesis, bone resorption, and perilacunar remodelling, while promoting bone formation, decreasing osteocyte apoptosis, and downregulating genes associated with secondary mineralization and mechanosensitivity in ovariectomized rats. These findings suggest early intervention with Scl-Ab enhances bone formation and limits osteocyte apoptosis and subsequent secondary mineralization.

molecular biology↗

bioRxiv2022

A novel mechanobiological model of bone metastasis reveals that mechanical stimulation inhibits the pro-osteoclastogenic effects of breast cancer cells

Bone is highly susceptible to cancer metastasis, and both tumour and bone cells enable tumour invasion through a "vicious cycle" of biochemical signalling. Tumor metastasis into bone also alters biophysical cues to both tumour and bone cells, which are highly sensitive to their mechanical environment. However, the mechanobiological feedback between these cells that perpetuates this cycle has not been studied. Here, we develop highly novel in vitro and computational models to provide an advanced understanding of how tumor growth is regulated by the synergistic influence of tumour-bone cell signaling and mechanobiological cues. In particular, we develop the first multicellular healthy and metastatic bone models, which can account for physiological mechanical signals within a custom bioreactor. These models successfully recapitulated mineralization, mechanobiological responses, osteolysis and metastatic activity. Ultimately we demonstrate that mechanical stimulus provided protective effects against tumor-induced osteolysis, confirming the importance of mechanobiological factors in bone metastasis development.

bioengineering↗