Switch of the ovarian cancer cell to a calcifying phenotype in the calcification of ovarian cancer

Aggressiveness evaluation of borderline serous ovarian tumors by analysis of Psammoma bodies present in cancer tissues using micro-FTIR spectroscopy

Borderline ovarian tumor is a type of tumor with generally low malignant potential. However, these tumors pose diagnostic challenges with benign and malignant epithelial ovarian tumors because the clinical symptoms are similar and investigation procedures for specific diagnosis are still debated. In addition, a small number of borderlines transform into high-grade serous ovarian carcinoma with a poor prognosis. Therefore, tools improving a better characterization of high-risk subtypes of borderline tumors to enable understanding of possible unfavorable evolution are essential for patients' management. Psammoma bodies (PBs) are microcalcifications found both in serous epithelial ovarian cancer and serous borderline tumors with possible correlation with disease progression. In this work, the chemical composition of PBs found in the tissues of borderline, high-grade and low-grade ovarian tumors was evaluated using micro-FTIR spectroscopy. Applying principal component analysis to spectral data, it was observed that among the borderline tumors analyzed (1-bl,2-bland3-bl), the PBs of3-blshowed a different chemical content from that of the PBs of the high-grade and low-grade tumors, while the PBs of1-bland2-blappeared to have similar chemical content to the PBs of high- and low-grade tumors. The discriminating wavenumbers were found to be those related to carbonate CO32- (1454, 1413 cm-1and 872 cm-1) and phosphate PO43-(1018 cm-1and 960 cm-1) present in microcalcifications. A higher ratio between peak intensities at 1413 cm-1and 1018 cm-1(I1413/I1018) was observed in the PBs of3-blcompared with those of high- and low-grade ovarian carcinoma patients, which correlates with higher CO32- content. On the other hand, the PBs of1-bland2-blshowed a CO32-level close to that of the PBs of high- and low-grade patients. Several studies on microcalcifications in breast carcinoma have reported that increased carbonate content is related to decreased tumor aggressiveness. Therefore, case bl-3 appeared to be the less aggressive. The results obtained from FTIR analysis were in agreement with histopathological tumor classification and molecular analysis for BRAFV600E. The FTIR technique could become a reliable tool for identifying borderline low- and high-risk tumors.

Tumor therapy by targeting extracellular hydroxyapatite using novel drugs: A paradigm shift

BACKGROUND

It has been shown that tumor microenvironment (TME) hydroxyapatite (HAP) is typically associated with many malignancies and plays a role in tumor progression and growth. Additionally, acidosis in the TME has been reported to play a key role in selecting for a more aggressive tumor phenotype, drug resistance and desensitization to immunotherapy for many types of cancers. TME-HAP is an attractive target for tumor detection and treatment development since HAP is generally absent from normal soft tissue. We provide strong evidence that dissolution of hydroxyapatite (HAP) within the tumor microenvironment (TME-HAP) using a novel therapeutic can be used to kill cancer cells both in vitro and in vivo with minimal adverse effects.

METHODS

We developed an injectable cation exchange nano particulate sulfonated polystyrene solution (NSPS) that we engineered to dissolve TME-HAP, inducing localized acute alkalosis and inhibition of tumor growth and glucose metabolism. This was evaluated in cell culture using 4T1, MDA-MB-231 triple negative breast cancer cells, MCF10 normal breast cells, and H292 lung cancer cells, and in vivo using orthotopic mouse models of cancer that contained detectable microenvironment HAP including breast (MMTV-Neu, 4T1, and MDA-MB-231), prostate (PC3) and colon (HCA7) cancer using 18 F-NaF for HAP and 18 F-FDG for glucose metabolism with PET imaging. On the other hand, H292 lung tumor cells that lacked detectable microenvironment HAP and MCF10a normal breast cells that do not produce HAP served as negative controls. Tumor microenvironment pH levels following injection of NSPS were evaluated via Chemical Exchange Saturation (CEST) MRI and via ex vivo methods.

RESULTS

Within 24 h of adding the small concentration of 1X of NSPS (~7 μM), we observed significant tumor cell death (~ 10%, p < 0.05) in 4T1 and MDA-MB-231 cell cultures that contain HAP but ⟨2% in H292 and MCF10a cells that lack detectable HAP and in controls. Using CEST MRI, we found extracellular pH (pHe) in the 4T1 breast tumors, located in the mammary fat pad, to increase by nearly 10% from baseline before gradually receding back to baseline during the first hour post NSPS administration. in the tumors that contained TME-HAP in mouse models, MMTV-Neu, 4T1, and MDA-MB-231, PC3, and HCA7, there was a significant reduction (p<0.05) in 18 F-Na Fuptake post NSPS treatment as expected; 18 F-  uptake in the tumor = 3.8 ± 0.5 %ID/g (percent of the injected dose per gram) at baseline compared to 1.8 ±0.5 %ID/g following one-time treatment with 100 mg/kg NSPS. Of similar importance, is that 18 F-FDG uptake in the tumors was reduced by more than 75% compared to baseline within 24 h of treatment with one-time NSPS which persisted for at least one week. Additionally, tumor growth was significantly slower (p < 0.05) in the mice treated with one-time NSPS. Toxicity showed no evidence of any adverse effects, a finding attributed to the absence of HAP in normal soft tissue and to our therapeutic NSPS having limited penetration to access HAP within skeletal bone.

CONCLUSION

Dissolution of TME-HAP using our novel NSPS has the potential to provide a new treatment paradigm to enhance the management of cancer patients with poor prognosis.

Considerations on chemical composition of psammoma bodies: Automated detection strategy by infrared microspectroscopy in ovarian and thyroid cancer tissues

Ectopic calcifications are observed in many soft tissues and are associated with several diseases, including cancer. The mechanism of their formation and the correlation with disease progression are often unclear. Detailed knowledge of the chemical composition of these inorganic formations can be very helpful in better understanding their relationship with unhealthy tissue. In addition, information on microcalcifications can be very useful for early diagnosis and provide insight into prognosis. In this work the chemical composition of psammoma bodies (PBs) found in tissues of human ovarian serous tumors was examined. The analysis using Micro Fourier Transform Infrared Spectroscopy (micro-FTIR) revealed that these microcalcifications contain amorphous calcium carbonate phosphate. Moreover, some PB grains showed the presence of phospholipids. This interesting result corroborates the proposed formation mechanism reported in many studies according to which ovarian cancer cells switch to a calcifying phenotype by inducing the deposition of calcifications. In addition, other techniques as X-ray Fluorescence Spectroscopy (XRF), Inductively Coupled Plasma Optical Emission Spectroscopy(ICP-OES) and Scanning electron microscopy (SEM) with Energy Dispersive X-ray Spectroscopy (EDX) were performed on the PBs from ovary tissues to determine the elements present. The PBs found in ovarian serous cancer showed a composition comparable to PBs isolated from papillary thyroid. Based on the chemical similarity of IR spectra, using micro-FTIR spectroscopy combined with multivariate analysis, an automatic recognition method was constructed. With this prediction model it was possible to identify PBs microcalcifications in tissues of both ovarian cancers, regardless of tumor grade, and thyroid cancer with high sensitivity. Such approach could become a valuable tool for routine macrocalcification detection because it eliminates sample staining, and the subjectivity of conventional histopathological analysis.

Potential Role of Hydroxyapatite Nanocrystalline for Early Diagnostics of Ovarian Cancer

Calcification is one of the clinical and morphological manifestations of ovarian tumors and it begins at the initial stages of carcinogenesis. Thus, this process can be used for the early diagnostics of some malignant ovarian tumors. We compared the results of ultrasound and histology and found that calcifications of a size less than 200 μm are not detected by ultrasound. These calcified structures are round fragile particles of different sizes. In the EDX (Energy-dispersive X-ray spectroscopy) spectra, the main lines were from Ca and P, and the ratio of these elements corresponds to hydroxyapatite. Thus, we established that hydroxyapatite is the main mineral component of ovarian psammoma bodies and could be used for early diagnostics of ovarian malignant neoplasia.

Molecular Aspects and Prognostic Significance of Microcalcifications in Human Pathology: A Narrative Review

The presence of calcium deposits in human lesions is largely used as imaging biomarkers of human diseases such as breast cancer. Indeed, the presence of micro- or macrocalcifications is frequently associated with the development of both benign and malignant lesions. Nevertheless, the molecular mechanisms involved in the formation of these calcium deposits, as well as the prognostic significance of their presence in human tissues, have not been completely elucidated. Therefore, a better characterization of the biological process related to the formation of calcifications in different tissues and organs, as well as the understanding of the prognostic significance of the presence of these calcium deposits into human tissues could significantly improve the management of patients characterized by microcalcifications associated lesions. Starting from these considerations, this narrative review highlights the most recent histopathological and molecular data concerning the formation of calcifications in breast, thyroid, lung, and ovarian diseases. Evidence reported here could deeply change the current point of view concerning the role of ectopic calcifications in the progression of human diseases and also in the patients’ management. In fact, the presence of calcifications can suggest an unfavorable prognosis due to dysregulation of normal tissues homeostasis.