Overexpression of Lrp5 enhanced the anti-breast cancer effects of osteocytes in bone

Osteocytes are the most abundant cells in bone,which is a frequent site of breast cancer metastasis.Here,we focused on Wnt signaling and evaluated tumor-osteocyte interactions.In animal experiments,mammary tumor cells were inoculated into the mammary fat pad and tibia.The role of Lrp5-mediated Wnt signaling was examined by overexpressing and silencing Lrp5 in osteocytes and establishing a conditional knockout mouse model.The results revealed that administration of osteocytes or their conditioned medium(CM)inhibited tumor progression and osteolysis.Osteocytes overexpressing Lrp5 or β-catenin displayed strikingly elevated tumor-suppressive activity,accompanied by downregulation of tumor-promoting chemokines and upregulation of apoptosis-inducing and tumor-suppressing proteins such as p53.The antitumor effect was also observed with osteocyte-derived CM that was pretreated with a Wnt-activating compound.Notably,silencing Lrp5 in tumors inhibited tumor progression,while silencing Lrp5 in osteocytes in conditional knockout mice promoted tumor progression.Osteocytes exhibited elevated Lrp5 expression in response to tumor cells,implying that osteocytes protect bone through canonical Wnt signaling.Thus,our results suggest that the Lrp5/β-catenin axis activates tumor-promoting signaling in tumor cells but tumor-suppressive signaling in osteocytes.We envision that osteocytes with Wnt activation potentially offer a novel cell-based therapy for breast cancer and osteolytic bone metastasis.

Mechanical tibial loading remotely suppresses brain tumors by dopamine-mediated downregulation of CCN4

Mechanical loading to the bone is known to be beneficial for bone homeostasis and for suppressing tumor-induced osteolysis in the loaded bone.However,whether loading to a weight-bearing hind limb can inhibit distant tumor growth in the brain is unknown.We examined the possibility of bone-to-brain mechanotransduction using a mouse model of a brain tumor by focusing on the response to Lrp5-mediated Wnt signaling and dopamine in tumor cells.The results revealed that loading the tibia with elevated levels of tyrosine hydroxylase,a rate-limiting enzyme in dopamine synthesis,markedly reduced the progression of the brain tumors.The simultaneous application of fluphenazine(FP),an antipsychotic dopamine modulator,enhanced tumor suppression.Dopamine and FP exerted antitumor effects through the dopamine receptors DRD1 and DRD2,respectively.Notably,dopamine downregulated Lrp5 via DRD1 in tumor cells.A cytokine array analysis revealed that the reduction in CCN4 was critical for loading-driven,dopamine-mediated tumor suppression.The silencing of Lrp5 reduced CCN4,and the administration of CCN4 elevated oncogenic genes such as MMP9,Runx2,and Snail.In summary,this study demonstrates that mechanical loading regulates dopaminergic signaling and remotely suppresses brain tumors by inhibiting the Lrp5-CCN4 axis via DRD1,indicating the possibility of developing an adjuvant bone-mediated loading therapy.

Spontaneous pneumothorax in a 17-year-old male patient with multiple exostoses:A case report and review of the literature

BACKGROUND Multiple exostoses generally develop in the first decade of life.They most frequently arise from the distal femur,proximal tibia,fibula,and proximal humerus.Costal exostoses are rare,contributing to 1%-2% of all exostoses in hereditary multiple exostoses(HME).They are usually asymptomatic,but a few cases have resulted in severe thoracic injuries.Pneumothorax caused by costal exostoses is rare,with only 13 previously reported cases.We report a new case of pneumothorax caused by costal exostoses.CASE SUMMARY A 17-year-old male with HME underwent surgery for removal of exostoses around his right knee.Four months following the operation,he felt chest pain when he was playing the trumpet;however,he did not stop playing for a week.He was referred to our hospital with a chief complaint of chest pain.The computed tomography(CT)scan revealed right pneumothorax and multiple exostoses in his right ribs.The CT scan also revealed visceral pleura thickness and damaged lung tissues facing the exostosis of the seventh rib.We diagnosed that exostosis of the seventh rib induced pneumothorax.Costal exostosis resection was performed by video-assisted thoracoscopic surgery(VATS)2 wk after the onset.The patient’s postoperative course was uneventful,and there was no recurrence of pneumothorax for 2 years.CONCLUSION Costal exostoses causing thoracic injuries should be resected regardless of age.VATS must be considered in cases with apparently benign and relatively small exostoses or HME.

A Minimally Invasive Surgery for Bone Metastases Using the Combination of Photodynamic Therapy and Hyperthermia Treatment

Cancer patients with bone metastases in their extremities may require surgical intervention to prevent deterioration in their quality of life due to a pathological fracture or severe bone pain. However, curative surgical interventions sometimes have severe complications due to the status of the original cancers. To avoid the decreased quality of life caused by bone metastasis, minimally invasive surgery that avoids additional surgical morbidity is required. We have established two therapeutic treatments for bone metastasis, a photodynamic acridine orange treatment (AOT) and an electronic magnetic hyperthermia treatment (EMHT). The present study investigated the clinical outcomes of combination therapy with EMHT and AOT for patients with bone metastases in their extremities. Methods: The study included 6 patients with 7 bone cancer metastasis locations. For bone metastases, all patients received intraregional tumor excision supported by AOT, in which photodynamic and radiodynamic therapy kills tumor cells during surgery with minimal damage to normal tissues. After the curettage, bone reconstruction was performed by using magnetic materials with calcium phosphate cement. EMHT was repeatedly performed after surgery. In EMHT, tumor cells are killed with an electric magnetic field generator, and bony union is promoted by electronic stimulation. Results: The mean duration of follow-up was 14 months. During the follow-up period, only one patient experienced a local recurrence, and this recurrence occurred 14 months after surgery. Bony union occurred in 4 of 5 cases (80%), and the pain score was significantly reduced after surgery. Conclusions: In the present study, AOT reduced the invasiveness of surgery. EMHT reduced the tumor growth without major complications and promoted bone formation after surgery. Our clinical results confirmed that EMHT and AOT combination therapy for bone metastasis can preserve limb function without local recurrence or bone absorption.