P2RX7 inhibition reduces breast cancer induced osteolytic lesions - implications for bone metastasis

Breast cancer metastasis to bone is a major contributor to morbidity and mortality in patients and remains an unmet clinical need. Purinergic signalling via the P2X7 receptor (P2RX7) in the primary tumour microenvironment is associated with progression of several cancers. It has also now become evident that intra-tumoural hypoxia facilitates cancer metastasis and reduces patient survival. In this study, we present data suggesting that hypoxia regulates the expression of P2RX7 in the primary tumour microenvironment; and importantly, inhibition with a selective antagonist (10mg/kg A740003) increased cancer cell death via apoptosis in a E0771/C57BL-6J syngeneic murine model. Furthermore, micro-computed tomography demonstrated reduced number of osteolytic lesions and lesion area following P2RX7 inhibition in absence of overt metastases by decreasing osteoclast numbers. We also demonstrate that activation of P2RX7 plays a role in the secretion of extracellular vesicles (EVs) from breast cancer cells. Mass-spectrometric analyses showed a distinct protein signature for EVs derived from hypoxic compared with normoxic cancer cells which elicit specific responses in bone cells that are associated with pre-metastatic niche formation. Thus, inhibiting P2RX7 provides a novel opportunity to preferentially target the hypoxic breast cancer cells preventing tumour progression and subsequent metastasis to bone

Feasibility of artificial intelligence–supported assessment of bone marrow infiltration using dual-energy computed tomography in patients with evidence of monoclonal protein — a retrospective observational study

Objectives To demonstrate the feasibility of an automated, non-invasive approach to estimate bone marrow (BM) infiltration of multiple myeloma (MM) by dual-energy computed tomography (DECT) after virtual non-calcium (VNCa) post-processing. Methods Individuals with MM and monoclonal gammopathy of unknown significance (MGUS) with concurrent DECT and BM biopsy between May 2018 and July 2020 were included in this retrospective observational study. Two pathologists and three radiologists reported BM infiltration and presence of osteolytic bone lesions, respectively. Bone mineral density (BMD) was quantified CT-based by a CE-certified software. Automated spine segmentation was implemented by a pre-trained convolutional neural network. The non-fatty portion of BM was defined as voxels > 0 HU in VNCa. For statistical assessment, multivariate regression and receiver operating characteristic (ROC) were conducted. Results Thirty-five patients (mean age 65 ± 12 years; 18 female) were evaluated. The non-fatty portion of BM significantly predicted BM infiltration after adjusting for the covariable BMD (p = 0.007, r = 0.46). A non-fatty portion of BM > 0.93% could anticipate osteolytic lesions and the clinical diagnosis of MM with an area under the ROC curve of 0.70 [0.49–0.90] and 0.71 [0.54–0.89], respectively. Our approach identified MM-patients without osteolytic lesions on conventional CT with a sensitivity and specificity of 0.63 and 0.71, respectively. Conclusions Automated, AI-supported attenuation assessment of the spine in DECT VNCa is feasible to predict BM infiltration in MM. Further, the proposed method might allow for pre-selecting patients with higher pre-test probability of osteolytic bone lesions and support the clinical diagnosis of MM without pathognomonic lesions on conventional CT. Key Points • The retrospective study provides an automated approach for quantification of the non-fatty portion of bone marrow, based on AI-supported spine segmentation and virtual non-calcium dual-energy CT data. • An increasing non-fatty portion of bone marrow is associated with a higher infiltration determined by invasive biopsy after adjusting for bone mineral density as a control variable (p = 0.007, r = 0.46). • The non-fatty portion of bone marrow might support the clinical diagnosis of multiple myeloma when conventional CT images are negative (sensitivity 0.63, specificity 0.71).

Brown Tumors of the Mandible Revealing Hyperparathyroidism: About Two Cases

The diagnosis of osteolytic lesions of the jaws can be challenging. Case Reports: Two cases of brown tumor of hyperparathyroidism were reported. A 76- year-old female patient presented with indolent swelling of her right lower jaw measuring approximately 5 cm /6 cm. The panoramic radiograph showed a well-defined osteolytic radiolucency involving the entire mandibular symphysis. Blood investigations revealed High level of parathyroid Hormone (PTH): 102pg/ml. The diagnosis of a brown tumor of hyperparathyroidism was suspected. A parathyroid technetium scintiscan revealed abnormally high uptake at the lower pole of the thyroid lobe interpreted as hyperplasia of right inferior parathyroid gland with possible brown tumor of the mandible. Second case: A 36- year-old female patient presented for the replacement of her missing teeth. Her medical history revealed chronic renal failure and a recent surgical excision of an Osteitis fibrosa cystica of her fifth left proximal phalange. Panoramic radiograph showed multiple well defined osteolytic lesions of the mandible. The diagnosis of a brown tumor of the mandible secondary to hyperparathyroidism was suspected. Laboratory investigations showed increased PTH level, serum hypocalcemia and hyperphosphatemia and vitamin D deficiency. The patient was referred to the department of endocrinology for further investigation and the correction of PTH level. At Six months follow up all the lesions disappeared on radiological control. Discussion: Brown tumor of hyperparathyroidism is a metabolic disorder causing bone resorption that can affect the jaw bones. Clinical symptoms depend on the size and the location of the lesion. Radiographically, it appears as radiolucent unique or multiple well-defined intra-osseous radiolucency. Biological examination is the key to the diagnosis and it is marked by high level of parathyroid hormone (PTH). Key words: Jaw, Tumors, Osteitis Fibrosa Cystica, Hyperparathyroidism, Diagnosis.

IL4/IL4R signaling promotes the osteolysis in metastatic bone of CRC through regulating the proliferation of osteoclast precursors

Background Bone metastasis of colorectal cancer (CRC) often indicates a poor prognosis. Osteolysis can be observed in metastatic sites, implying an aberrant activation of osteoclasts. However, how osteoclastogenesis is regulated in metastatic microenvironment caused by colorectal cancer is still unclear. Methods In this study, mice bone metastatic model of CRC was established through injection of MC-38 or CT-26 cells. BrdU assays showed primary CD115 ( +) osteoclast precursors (OCPs) proliferated at the first 2 weeks. Transcriptomic profiling was performed to identify differentially expressing genes and pathways in OCPs indirectly co-cultured with CRC cells Results The expression of IL4Rα was found to be significantly upregulated in OCPs stimulated by tumor conditioned medium (CM). Further investigation indicated that IL-4 signaling regulated proliferation of OPCs through interacting with type I IL4 receptor, and neutrophils were the main source of IL-4 in bone marrow. The proliferation of OCPs can be inhibited in IL4 deficiency mice. In addition, ERK pathway was activated by IL4/IL4R signaling. Ravoxertinib, an ERK antagonists, could significantly prevent bone destruction through inhibiting the proliferation of OCPs. Conclusion Our study indicates the essential role of IL4/IL4R signaling for the proliferation of OCPs in early metastasis of CRC predominantly through activating ERK pathway, which remarkedly impacts the number of osteoclasts in later stage and leads to osteolytic lesions. Moreover, Ravoxertinib could be a new therapeutical target for bone metastasis of CRC.

A rare case of an expansile spinopelvic aneurysmal bone cyst managed with embolization, excision, and fusion

Background: Aneurysmal bone cysts (ABC) are benign osteolytic lesions of the metaphyseal regions of long bones that typically contribute to rapid bony expansion. Here, we present an ABC involving the spinopelvic region in a 15-year-old male that required embolization, surgical excision, and fusion. Case Description: A 15-year-old male, presented with gradually progressive painful lower back swelling of 4 months’ duration. Once the diagnosis of an ABC was established based on a combination of X-ray, MR, and CT studies, he underwent selective arterial embolization, extended surgical excision (i.e. curettage), with a posterior fusion. Two years postoperatively, the patient remained neurologically intact without radiographic evidence of lesion recurrence. Conclusion: Large expansile ABC involving the vertebral bodies should be managed with preoperative selective arterial embolization, surgical decompression/curettage, and spinopelvic fixation.

Identification of biomarkers and signaling pathways during the treatment of multiple myeloma

Multiple myeloma (MM) is an incurable hematologic malignancy, which is characterized by increased bone marrow plasma cells, osteolytic lesions, and anemia. Here, our aim is to characterize significant biomarkers and signaling pathways during the treatment of MM by using bioinformatic methods. The GSE180018 dataset was generated by DNBSEQ-G400 (Homo sapiens). The KEGG and GO analyses showed the biological processes such as " Protein export”, “Protein processing in endoplasmic reticulum”, “Vibrio cholerae infection”, “Fc gamma R-mediated phagocytosis" are mainly affected in FOXM1 KO MM cells. Moreover, we identified the significant genes including CD44, NOTCH1, SELL, RAC2, HSPA8, VAV1, DDIT3, PLK1, HYOU1, ITGAL in FOXM1 KO MM cells. Therefore, our study may provide further guidance for the drug development of MM.

Prediction of Malignant Cell Infiltration Patterns with Texture Features of Biopsy-Correlated Positron Emission Tomography of Osteolytic Lesions in Multiple Myeloma

Introduction: Osteolytic bone disease represents a severe clinical presentation of multiple myeloma (MM), as MM cells infiltrate the bone marrow throughout the skeleton, forming tumors, activating bone-resorbing osteoclasts, and impeding bone-depositing osteoblast activity. The extent of osteolytic lesions encompassing the skeleton influences the severity of disease for patients, with severe lesions leading to skeletal-related events (SREs). MM cell infiltration into the bone marrow gradually increases with disease progression; however, the distribution of myeloma cells within the bone and marrow is heterogenous. Standard of care imaging modalities used to monitor the number, size, and extent of bone destruction of lesions include whole-body magnetic resonance imaging (MRI), whole-body low-dose computed tomography (CT), and positron emission tomography with CT (PET/CT). With the use of computational methodologies, imaging textural features can be calculated from PET. In this prospective study, we aim to find PET textural features that will correlate with histological evaluation of myeloma cell infiltration patterns of osteolytic lesions and un-guided bone marrow biopsies in MM patients. Patients and Methods: 40 patients were enrolled in this prospective study with either newly diagnosed multiple myeloma (n=16, 40%) or relapse/refractory multiple myeloma (n= 24, 60%). Whole-body PET/CT imaging was performed on all patients as part of MM standard of care, after which CT-guided biopsies were taken from patient osteolytic lesions identified by imaging and in bone marrow biopsies. 68 biopsies were evaluated by an expert hematopathologist, of which 59 had analyzable imaging studies in the respective areas. Myeloma cell infiltration patterns in all biopsies were classified as interstitial (n=23, 41.8%), nodular (n=19, 34.6%), or packed (n=13, 23.6%), as described by Andrulis et al. (2014). PET lesion and bone marrow segmentation was performed on the Medical Imaging Interaction Toolkit (MITK) and 72 textural features were calculated using the PyRadiomics extension (van Griethuysen et al. 2017) for 3D Slicer 4.11 (Fedorov et al. 2012). PET quantitative features were calculated using the PET IndiC extension from 3D Slicer (QIICR (2015b)). Statistical analysis was performed via GraphPad Prism 9 (GraphPad Software, San Diego, California USA) and the Radiomics Analysis with R (RadAR, Benelli et al. 2020) package in the RStudio environment (RStudio Team (2020). RStudio: Integrated Development for R. RStudio, PBC, Boston, MA). Results: Lesion biopsy samples predominantly favored packed infiltration pattern (53.6%) over interstitial (21.4%) or nodular (25%), while staging/follow-up bone marrow biopsies predominantly favored interstitial or nodular patterns (47.5% and 35.0%, respectively) compared to packed (22.5%). Two-way analysis of variance (ANOVA) tests was performed to compare imaging features between biopsy infiltration patterns and also between disease status of patients. The first order uniformity (p<0.05) was able to discern between interstitial, nodular, or packed infiltration for all biopsies and textural features from the Gray Level Co-Occurrence Matrix (GLCM) Correlation and Joint Entropy were accurately able to discern between interstitial and either nodular or packed infiltration patterns for all biopsies (p<0.01). Within lesion biopsies specifically (n=25), first order uniformity, kurtosis, skewness, and textural features Joint Entropy and Dependence Non-Uniformity could discern between MM cell infiltration patterns (p<0.05). PET quantitative SUV statistics did not show any significant separation between infiltration patterns. First order, textural, and PET SUV quantitative features could not distinguish disease status of the patient. Conclusions: In this preliminary study, we demonstrate a correlation between textural imaging features and pathological findings within the bone marrow and osteolytic lesions of MM patients. This correlation illustrates a potential link between computational imaging features to predict pathological findings in patients with MM. Further expansion of this study with genomic, flow cytometry, and multimodality imaging data could lead to the generation of computational modeling of the pathophysiology of osteolytic lesions in MM and a reduction in the need for invasive bone marrow and lesion biopsies. Figure 1 Figure 1. Disclosures Merz: Takeda: Honoraria; onkowissen.de: Honoraria; Amgen: Honoraria; BMS: Honoraria; Celgene: Honoraria; Sanofi: Honoraria; Janssen: Honoraria; GSK: Honoraria; Hexal: Honoraria. McCarthy: Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bluebird: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Juno: Honoraria, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Magenta Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees. Hillengass: Beijing Life Oasis Public Service Center: Speakers Bureau; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Axxess Network: Membership on an entity's Board of Directors or advisory committees; Beijing Medical Award Foundation: Speakers Bureau; Adaptive: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Skyline: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Oncotracker: Membership on an entity's Board of Directors or advisory committees; Curio Science: Speakers Bureau.