Targeted Agents in Preclinical and Early Clinical Development for the Treatment of Cancer Bone Metastases

The role of cytoreductive radical prostatectomy and lymph node dissection in bone-metastatic prostate cancer: A population-based study

BACKGROUNDS

The role of cytoreductive radical prostatectomy (cRP) for bone-metastatic prostate cancer (bmPCa) remains controversial. We aimed to figure out whether cRP and lymph node dissection (LND) can benefit bmPCa.

METHODS

11,271 PCa patients with bone metastatic burden from 2010 to 2019 were identified using SEER-Medicare. Overall survival (OS) and cancer-specific survival (CSS) rates were visualized using Kaplan-Meier plots. Multivariable Cox regression analyses were constructed to examine the effects of cRP and LND on survival, after stratifying to age, prostate specific antigen (PSA), clinical stages, Gleason score, metastatic burden, radiotherapy, and chemotherapy status.

RESULTS

317 PCa patients underwent cRP and cRP was increasingly performed for bmPCa from 2010 (2.2%) to 2019 (3.0%) (p < 0.05). In multi analyses, cRP was predisposed to a better OS or CSS in patients with age < 75, PSA < 98 ng/mL, bone-only metastatic sites or patients not receiving chemotherapy (all p < 0.05). For the patients undergoing cRP, LND especially extended LND was associated with a better OS or CSS (all p < 0.05).

CONCLUSIONS

cRP might benefit OS or CSS in young patients with low PSA and bone-only metastatic sites not receiving chemotherapy. And a clear OS or CSS benefit of LND especially extended LND was observed in patients undergoing cRP.

Pantoprazole (PPZ) Inhibits RANKL-Induced Osteoclast Formation and Function In Vitro and Prevents Lipopolysaccharide- (LPS-) Induced Inflammatory Calvarial Bone Loss In Vivo

Bone remodeling is a process delicately balanced between osteoclastic bone resorption and osteoblastic bone formation. Osteoclasts (OCs) are multinucleated giant cells formed through the fusion of monocytic precursors of the hematopoietic stem cells lineage. OCs are the exclusive cells responsible for the resorption and degradation of the mineralized bone matrix. Pantoprazole (PPZ), a proton pump inhibitor (PPI), is commonly prescribed to reduce excess gastric acid production for conditions such as gastroesophageal reflux disease and peptic ulcer disease. Studies have found contradictory effects of PPI therapy on bone metabolism due to the lack of understanding of the exact underlying mechanism. In this study, we found that PPZ inhibits receptor activator of nuclear factor-κB (NF-κB) ligand- (RANKL-) induced osteoclastogenesis from bone marrow monocytic/macrophage (BMMs) precursors and the bone-resorbing activity of mature OCs. Correspondingly, the expression of OC marker genes was also attenuated. At the molecular level, PPZ treatment was associated with reduced activation of the ERK MAPK signaling pathways crucial to OC differentiation. Additionally, the in vivo administration of PPZ protected mice against lipopolysaccharide- (LPS-) induced inflammatory calvarial bone erosion, as a result of the reduced number and activity of OCs on the calvarial bone surface. Although PPI use is associated with increased risk of osteoporosis and bone fractures, our study provides evidence for the direct inhibitory effect of PPZ on OC formation and bone resorption in vitro and in vivo, suggesting a potential therapeutic use of PPZ in the treatment of osteolytic disease with localized bone destruction.

Oral biosciences: The annual review 2019

BACKGROUND

Journal of Oral Biosciences is devoted to the advancement and dissemination of fundamental knowledge concerning every aspect of oral biosciences.

HIGHLIGHT

This review features review articles in the fields of "Bone Cell Biology," "Microbiology," "Oral Heath," "Biocompatible Materials," "Mouth Neoplasm," and "Biological Evolution" in addition to the review articles by winners of the Lion Dental Research Award ("Role of nicotinic acetylcholine receptors for modulation of microcircuits in the agranular insular cortex" and "Phospholipase C-related catalytically inactive protein: A novel signaling molecule for modulating fat metabolism and energy expenditure") and the Rising Members Award ("Pain mechanism of oral ulcerative mucositis and the therapeutic traditional herbal medicine hangeshashinto," "Mechanisms underlying the induction of regulatory T cells by sublingual immunotherapy," and "Regulation of osteoclast function via Rho-Pkn3-c-Src pathways"), presented by the Japanese Association for Oral Biology.

CONCLUSION

These reviews in the Journal of Oral Biosciences have inspired the readers of the journal to broaden their knowledge regarding various aspects of oral biosciences. The current editorial review introduces these exciting review articles.

Inhibition of miR-423-5p suppressed prostate cancer through targeting GRIM-19

OBJECTIVE

To determine the effect of miR-423-5p on the progression of prostate cancer (PC).

METHODS

miR-423-5p and GRIM-19 expressions were detected by qRT-PCR and western blot. PC cell proliferation was measured by MTT assay. PC cell apoptosis was detected by flow cytometry. Dual luciferase reporter assay was used to confirm the interaction between miR-423-5p and GRIM-19.

RESULTS

Compared with normal prostate tissues and prostate epithelial cell HPrEC, miR-423-5p was up-regulated in human PC tissues and PC3 cells, whereas GRIM-19 expression was decreased. Inhibition of miR-423-5p suppressed PC3 cell proliferation, promoted PC3 cell apoptosis, and decreased anti-apoptosis protein BCL-2 expression. GRIM-19 was a target of miR-423-5p, and GRIM-19 was negatively regulated by miR-423-5p in PC3 cells. In addition, miR-423-5p knockdown inhibited the proliferation and promoted the apoptosis of PC3 cells through GRIM-19. In vivo experiments showed that miR-423-5p inhibitor administration reduced tumor volume, down-regulated miR-423-5p and GRIM-19 expressions in PC tissues of nude mice.

CONCLUSION

Inhibition of miR-423-5p suppressed PC through targeting GRIM-19.

Bone metastasis: Interaction between cancer cells and bone microenvironment

BACKGROUND

Bone is one of the most common target organs for cancer metastasis, especially in patients with advanced breast and prostate cancers. Despite recent advances in therapeutic approaches, bone metastases remain incurable and produce multiple complications called skeletal-related events, including hypercalcemia, pathological fractures, spinal compression, and bone pain, which are associated with poor prognosis.

HIGHLIGHT

Although the precise mechanisms are yet to be fully elucidated, accumulating evidence suggests that bone provides a favorable microenvironment that enables circulating cancer cells to home, proliferate, and colonize, resulting in the formation of metastasis. Cancer cells that metastasize to bone also possess unique features, enabling them to utilize the bone microenvironment. Thus, communication between cancer cells and bone is believed to be critical for the development and progression of bone metastases.

CONCLUSION

Continued studies are warranted to understand the molecular mechanisms underlying bone metastases and to develop mechanism-based and effective therapeutic interventions.

Small molecule nAS-E targeting cAMP response element binding protein (CREB) and CREB-binding protein interaction inhibits breast cancer bone metastasis

Bone is the most common metastatic site for breast cancer. The excessive osteoclast activity in the metastatic bone lesions often produces osteolysis. The cyclic-AMP (cAMP)-response element binding protein (CREB) serves a variety of biological functions including the transformation and immortalization of breast cancer cells. In addition, evidence has shown that CREB plays a key role in osteoclastgenesis and bone resorption. Small organic molecules with good pharmacokinetic properties and specificity, targeting CREB-CBP (CREB-binding protein) interaction to inhibit CREB-mediated gene transcription have attracted more considerations as cancer therapeutics. We recently identified naphthol AS-E (nAS-E) as a cell-permeable inhibitor of CREB-mediated gene transcription through inhibiting CREB-CBP interaction. In this study, we tested the effect of nAS-E on breast cancer cell proliferation, survival, migration as well as osteoclast formation and bone resorption in vitro for the first time. Our results demonstrated that nAS-E inhibited breast cancer cell proliferation, migration, survival and suppressed osteoclast differentiation as well as bone resorption through inhibiting CREB-CBP interaction. In addition, the in vivo effect of nAS-E in protecting against breast cancer-induced osteolysis was evaluated. Our results indicated that nAS-E could reverse bone loss induced by MDA-MB-231 tumour. These results suggest that small molecules targeting CREB-CBP interaction to inhibit CREB-mediated gene transcription might be a potential approach for the treatment of breast cancer bone metastasis.

An update on the currently available and future chemotherapy for treating bone metastases in breast cancer patients

INTRODUCTION

Bone metastases in breast cancer patients are a common clinical problem. Many factors influence the treatment decision, including tumor characteristics, previous treatment and tumor burden in the treatment of metastatic breast cancer.

AREAS COVERED

This present review summarizes the new treatment strategies and the chemotherapeutic agents currently available in the management of metastatic breast cancer with bone metastases.

EXPERT OPINION

Patients with bone metastases more often have hormone receptor-positive tumours. Although new treatment agents for metastatic breast cancer have been investigated, endocrine therapy is still considered as the treatment of choice for patients with bone metastases although chemotherapy still has an important place. In recent years, new chemotherapeutic agents such as etirinotecan and nab-paclitaxel have been established though there are few studies that have looked at particular types of metastases. In the last decade, therapies for bone metastasis resistant to endocrine therapy have predominantly focused on radiotherapy, surgical resection, chemotherapy, bone-targeting radiopharmaceuticals and targeted therapeutics. New targeted agents include: Src inhibitors, cathepsin K inhibitors, CXCR4 inhibitors, TGF-B blockade and integrin antagonists while drug delivery systems for chemotherapy have also been developed. These new treatment options could be future treatment options for bone metastatic disease if early promising results are confirmed by clinical trials.

Osteon Myospalacem Baileyi attenuates osteoclast differentiation through RANKL induced NFAT pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Osteon Myospalacem Baileyi, known as Sai long gu (Tibetan language, means "blind rat bone"), is the whole skeleton of Tibet plateau rodentia animal Myospalacem Baileyi. Osteon Myospalacem Baileyi had been widely used in the Tibet region as an anti-osteoporosis drug and since 1991 Osteon Myospalacem Baileyi has been listed in the Pharmacopoeia of People's Republic of China as the first-class animal new medical material. However, the mechanism of its anti-osteoporosis activities is still unclear. It is very desirable to solve this problem for further study.

MATERIALS AND METHODS

in this study, preparative chromatography was employed to produce the active fraction ET4 from Osteon Myospalacem Baileyi crude. Flow cytometry and MTT assay were used to evaluate the toxicities of ET4. BMM cells were separated from mouse bone marrow to test the inhibition effects of ET4 on osteoclastogenesis. Western blot was used to find out the pathways, through which ET4 could act on osteoclastogenesis. Q-PCR was used to test the osteoclastogenesis marker genes. At last, immunofluorescence confocal microscopy was used to test the osteoclastogenesis master protein NFATc1 nuclei translocation.

RESULTS

In this study we report that ET4, at the dose of 60μg/mL, significantly inhibited the formation of osteoclasts. Notably, ET4 did not affect the BMM viability at that dose. In addition, Osteon Myospalacem Baileyi could inhibit the expression of osteoclast marker genes, including cathepsin K (CTSK), nuclear factor of activated T cells cytoplasmic 1 (NFATc1), tartrate resistant acid phosphatase (TRAP, Acp5) dendrite cell-specific transmembrane protein (DC-STAMP), calcitonin receptor (CTR), osteoclast associated and immunoglobulin-like receptor (OSCAR). Mechanistically, ET4 dose- and time-dependently blocked the RANKL-induced activation of ERK and c-Fos as well as the induction of NFATc1 which is essential for OC formation.

CONCLUSIONS

These data suggest that ET4 might be a useful alternative therapy in preventing or treating osteolytic diseases.

Sophoridine from Sophora Flower Attenuates Ovariectomy Induced Osteoporosis through the RANKL-ERK-NFAT Pathway

An imbalance in osteogenesis and osteoclastogenesis is a crucial pathological factor in the development of osteoporosis. Osteoclasts (OCs) play a pivotal role in osteoporosis, whose new therapy exploration has been focused on the suppression of OC formation. Sophoridine is found from the Chinese traditional food sophora flower to exhibit anti-osteoporosis capacity by screening. This study is focused on its anti-osteoporosis mechanism evaluation. The anti-osteoporosis effect of sophoridine, (15 mg kg^-1 body), was evaluated in ovariectomized (OVX) mice by monitoring changes in bone histomorphometry index, formation of osteoclasts from blood-derived mononuclear cells, and changes in the synthesis of pro-osteoclastogenic cytokines. Signal pathways were investigated by QPCR, Western blot, and immunofluorescence. Sophoridine has a significant anti-osteoporosis effect in vivo, which can inhibit RANKL-induced OC formation, the appearance of OC-specific marker genes, and OC marker protein in vitro. Mechanistically, sophoridine dose- and time-dependently blocks the RANKL-induced OC formation and the activation of ERK and c-Fos as well as the induction and nucleus translocation of NFATc1. Sophora flower might be a useful alternative functional food in preventing or treating osteoporosis.

Aggressive denosumab-related jaw necrosis - a case series

Medication related osteonecrosis of the jaw is becoming a repeatedly seen complication in cancer patients. Stage 0 of the disease is more likely to be seen by the patients' general dental practitioners. We are presenting four cases of MRONJ related to denosumab treatment showing increasingly aggressive pictures of the disease. Nevertheless, we also present a good response to a drug holiday arranged by the patients' treating oncologists.

Molecular Mechanisms of Bone Metastasis: Which Targets Came from the Bench to the Bedside?

Bone metastases ultimately result from a complex interaction between cancer cells and bone microenvironment. However, prior to the colonization of the bone, cancer cells must succeed through a series of steps that will allow them to detach from the primary tumor, enter into circulation, recognize and adhere to specific endothelium, and overcome dormancy. We now know that as important as the metastatic cascade, tumor cells prime the secondary organ microenvironment prior to their arrival, reflecting the existence of specific metastasis-initiating cells in the primary tumor and circulating osteotropic factors. The deep comprehension of the molecular mechanisms of bone metastases may allow the future development of specific anti-tumoral therapies, but so far the approved and effective therapies for bone metastatic disease are mostly based in bone-targeted agents, like bisphosphonates, denosumab and, for prostate cancer, radium-223. Bisphosphonates and denosumab have proven to be effective in blocking bone resorption and decreasing morbidity; furthermore, in the adjuvant setting, these agents can decrease bone relapse after breast cancer surgery in postmenopausal women. In this review, we will present and discuss some examples of applied knowledge from the bench to the bed side in the field of bone metastasis.