A phase 2 trial exploring the clinical and correlative effects of combining doxycycline with bone-targeted therapy in patients with metastatic breast cancer

Inside a Metastatic Fracture: Molecular Bases and New Potential Therapeutic Targets

INTRODUCTION

Bone metastases and pathological fractures significantly impact the prognosis and quality of life in cancer patients. However, clinical and radiological features alone have been shown to fail to predict skeletal related events of a bone metastasis (SREs).

AIM

This study focuses on key molecular players including Matrix Metalloproteinases (MMPs), Integrins, Bone Morphogenetic Proteins (BMPs), Parathormone-related Protein (PTHrP).

RESULTS

The RANK/RANKL/Osteoprotegerin (OPG) pathway, and N-terminal peptide (NTx), involved in the metastatic process and bone integrity disruption. Elevated levels of these molecules have been pointed out as potential biomarkers for predicting SREs, but they have been poorly investigated. Moreover, batimastat, marimastat, tanomastat, andecaliximab, and HIV protease targeting MMPs; Volociximab/M200, cilengitide, abituzumab, and FAK inhibitors targeting integrins; LDN193189, DMH1, and ISLR modulators targeting BMPs; and PTH (7-33)-CBD targeting PTHrP have shown promising results antagonizing these molecules, but no effect on preventing and managing metastatic fractures has been assessed yet.

CONCLUSIONS

This paper underscores the importance of advanced molecular biology and transcriptomics in identifying novel therapeutic targets. The integration of these biomarkers with clinical and radiological assessments using artificial intelligence tools could revolutionize the diagnostics and treatment strategies for patients with bone metastases.

Repurposing approved non-oncology drugs for cancer therapy: a comprehensive review of mechanisms, efficacy, and clinical prospects

Cancer poses a significant global health challenge, with predictions of increasing prevalence in the coming years due to limited prevention, late diagnosis, and inadequate success with current therapies. In addition, the high cost of new anti-cancer drugs creates barriers in meeting the medical needs of cancer patients, especially in developing countries. The lengthy and costly process of developing novel drugs further hinders drug discovery and clinical implementation. Therefore, there has been a growing interest in repurposing approved drugs for other diseases to address the urgent need for effective cancer treatments. The aim of this comprehensive review is to provide an overview of the potential of approved non-oncology drugs as therapeutic options for cancer treatment. These drugs come from various chemotherapeutic classes, including antimalarials, antibiotics, antivirals, anti-inflammatory drugs, and antifungals, and have demonstrated significant antiproliferative, pro-apoptotic, immunomodulatory, and antimetastatic properties. A systematic review of the literature was conducted to identify relevant studies on the repurposing of approved non-oncology drugs for cancer therapy. Various electronic databases, such as PubMed, Scopus, and Google Scholar, were searched using appropriate keywords. Studies focusing on the therapeutic potential, mechanisms of action, efficacy, and clinical prospects of repurposed drugs in cancer treatment were included in the analysis. The review highlights the promising outcomes of repurposing approved non-oncology drugs for cancer therapy. Drugs belonging to different therapeutic classes have demonstrated notable antitumor effects, including inhibiting cell proliferation, promoting apoptosis, modulating the immune response, and suppressing metastasis. These findings suggest the potential of these repurposed drugs as effective therapeutic approaches in cancer treatment. Repurposing approved non-oncology drugs provides a promising strategy for addressing the urgent need for effective and accessible cancer treatments. The diverse classes of repurposed drugs, with their demonstrated antiproliferative, pro-apoptotic, immunomodulatory, and antimetastatic properties, offer new avenues for cancer therapy. Further research and clinical trials are warranted to explore the full potential of these repurposed drugs and optimize their use in treating various cancer types. Repurposing approved drugs can significantly expedite the process of identifying effective treatments and improve patient outcomes in a cost-effective manner.

Doxycycline-Induced Changes in Circulating MMP or TIMP2 Levels Are Not Associated with Skeletal-Related Event-Free or Overall Survival in Patients with Bone Metastases from Breast Cancer

Doxycycline is often used as a promoter of inducible gene expression in preclinical models; however, it can also have direct effects on tumor growth and survival. This is due in part to its ability to inhibit cell invasion and regulate matrix metalloproteinase (MMP) expression. Given that doxycycline is also osteotropic, a clinical study to assess its effects on modulation of tumor progression or prevention of skeletal-related events (SRE) in patients with bone metastases from breast cancer (the Achilles trial) was undertaken. Patients received 100 mg of oral doxycycline twice daily for 12 weeks, with serum obtained at baseline and 4, 8 and 12 weeks post-initiation of doxycycline treatment. Exploratory analysis of the effects of doxycycline on circulating levels of MMP or tissue inhibitor of matrix metalloproteinase 2 (TIMP2) was performed in enrolled patients. Statistically significant associations were observed between MMP2, MMP9 and TIMP2 at baseline with significant associations maintained between absolute levels and changes in levels of MMP2 and TIMP2 at weeks 4-12 post initiation of doxycycline. Treatment with doxycycline generally resulted in decreases in MMP2 and MMP9 levels with concurrent upregulation of TIMP2 at 12 weeks post-initiation of doxycycline treatment. Despite this, we observed no association with the levels of any of these factors with either SRE-free or overall survival in this patient cohort. In summary, despite observing hypothesized effects of doxycycline administration on surrogate markers of its anti-tumor activity, measures of circulating levels of these biomarkers were not prognostic in this patient population.

The multifaceted roles of mitochondria at the crossroads of cell life and death in cancer

Mitochondria are the cytoplasmic organelles mostly known as the "electric engine" of the cells; however, they also play pivotal roles in different biological processes, such as cell growth/apoptosis, Ca²⁺ and redox homeostasis, and cell stemness. In cancer cells, mitochondria undergo peculiar functional and structural dynamics involved in the survival/death fate of the cell. Cancer cells use glycolysis to support macromolecular biosynthesis and energy production ("Warburg effect"); however, mitochondrial OXPHOS has been shown to be still active during carcinogenesis and even exacerbated in drug-resistant and stem cancer cells. This metabolic rewiring is associated with mutations in genes encoding mitochondrial metabolic enzymes ("oncometabolites"), alterations of ROS production and redox biology, and a fine-tuned balance between anti-/proapoptotic proteins. In cancer cells, mitochondria also experience dynamic alterations from the structural point of view undergoing coordinated cycles of biogenesis, fusion/fission and mitophagy, and physically communicating with the endoplasmic reticulum (ER), through the Ca²⁺ flux, at the MAM (mitochondria-associated membranes) levels. This review addresses the peculiar mitochondrial metabolic and structural dynamics occurring in cancer cells and their role in coordinating the balance between cell survival and death. The role of mitochondrial dynamics as effective biomarkers of tumor progression and promising targets for anticancer strategies is also discussed.

Proteases Regulate Cancer Stem Cell Properties and Remodel Their Microenvironment

Proteolytic activity is perturbed in tumors and their microenvironment, and proteases also affect cancer stem cells (CSCs). CSCs are the therapy-resistant subpopulation of cancer cells with tumor-initiating capacity that reside in specialized tumor microenvironment niches. In this review, we briefly summarize the significance of proteases in regulating CSC activities with a focus on brain tumor glioblastoma. A plethora of proteases and their inhibitors participate in CSC invasiveness and affect intercellular interactions, enhancing CSC immune, irradiation, and chemotherapy resilience. Apart from their role in degrading the extracellular matrix enabling CSC migration in and out of their niches, we review the ability of proteases to modulate CSC properties, which prevents their elimination. When designing protease-oriented therapies, the multifaceted roles of proteases should be thoroughly investigated.

Clinical Therapy of Metastatic Spinal Tumors

Metastatic spinal tumors (MST) have high rates of morbidity and mortality. MST can destroy the vertebral body or compress the nerve roots, resulting in an increased risk of pathological fractures and intractable pain. Here, we elaborately reviewed the currently available therapeutic options for MST according to the following four aspects: surgical management, minimally invasive therapy (MIT), radiation therapy, and systemic therapy. In particular, these aspects were classified and introduced to show their developmental process, clinical effects, advantages, and current limitations. Furthermore, with the improvement of treatment concepts and techniques, we discovered the prevalent trend toward the use of radiation therapy and MIT in clinic therapies. Finally, the future directions of these treatment options were discussed. We hoped that along with future advances and study will lead to the improvement of living standard and present status of treatment in patients with MST.

Adjuvant bisphosphonate use in patients with early stage breast cancer: Patient perspectives on treatment acceptability and potential de-escalation

Background

Despite the increasing use of adjuvant bisphosphonates for early stage breast cancer (EBC), little is known about the patient experience with such treatments. A patient survey was performed to identify current prescribing practices, perceptions around the role of treatment, the impact of treatment on patients' quality of life, and future trial designs.

Methods

EBC patients who had either completed or were currently receiving adjuvant bisphosphonates were sent an anonymized survey. The survey collected information on patient and disease characteristics, bisphosphonate scheduling, compliance, and tolerance. Questions also assessed patient interest in trials of de-escalated bisphosphonate therapy.

Results

A total of 255 patients were contacted, with 164 eligible respondents (eligible response rate 164/255, 64.3%). Median patient age was 52 years (range 28 to 82 years). The majority (111/163, 68.1%) were postmenopausal at the time of diagnosis, 23.3% (38/163) were premenopausal, and 7.4% (12/163) were perimenopausal. Most patients (78%) had received chemotherapy. Zoledronate was the most commonly used bisphosphonate (92%), with the majority receiving treatment every 6 months for 3 years (73%). While 66% (107/161) of respondents had experienced side effects with treatment, most had, or expected to, complete treatment (154/163, 94%). Provided there was no detriment in breast cancer outcomes, there was strong interest in future studies of de-escalating adjuvant bisphosphonate therapy.

Conclusion

While most patients tolerate their treatment, there is interest in performing trials of de-escalation of these agents.

The Impact of Matrix Metalloproteinase-9 on the Sequential Steps of the Metastatic Process

In industrialized countries, cancer is the second leading cause of death after cardiovascular disease. Most cancer patients die because of metastases, which consist of the self-transplantation of malignant cells in anatomical sites other than the one from where the tumor arose. Disseminated cancer cells retain the phenotypic features of the primary tumor, and display very poor differentiation indices and functional regulation. Upon arrival at the target organ, they replace preexisting, normal cells, thereby permanently compromising the patient's health; the metastasis can, in turn, metastasize. The spread of cancer cells implies the degradation of the extracellular matrix by a variety of enzymes, among which the matrix metalloproteinase (MMP)-9 is particularly effective. This article reviews the available published literature concerning the important role that MMP-9 has in the metastatic process. Additionally, information is provided on therapeutic approaches aimed at counteracting, or even preventing, the development of metastasis via the use of MMP-9 antagonists.

Long Non-Coding RNA (LncRNA) HOXA11-AS Promotes Breast Cancer Invasion and Metastasis by Regulating Epithelial-Mesenchymal Transition

BACKGROUND To detect the expression of lncRNA HOXA11-AS and its biological effect in breast cancer. MATERIAL AND METHODS In this study, fluorescent quantitative real-time PCR (qRT-PCR), MTT assay and clone formation assay, flow cytometry, Transwell assay and wound healing assay, immunofluorescence, and Western blot analysis were conducted to detect the expression of lncRNA HOXA11-AS, cell proliferation activity, cell apoptosis rate and cell cycle distribution, the changes of cell invasion and metastasis capacity, and the expressions of molecular markers of epithelial-mesenchymal transition (EMT), respectively. Additionally, a nude mouse metastatic tumor model was established to study the influence of lncRNA HOXA11-AS on invasion and metastasis capacity of breast cancer cells. RESULTS The qRT-PCR experiment results showed that HOXA11-AS expression in breast cancer tissue of 50 patients was relatively higher than that in tissue adjacent to cancer. MTT assay suggested that tumor cell proliferation capacity was suppressed followed by the knockdown of lncRNA HOXA11-AS expression in MDA-MB-231 and MCF-7 cells; flow cytometry results demonstrated that interfering in lncRNA HOXA11-AS could induce tumor cell apoptosis and promote cell cycle progression to be arrested in G1/G0 stage; experiments in vivo/vitro manifested that interfering in lncRNA HOXA11-AS could inhibit tumor cell invasion and migration capacity by affecting the expressions of EMT-related molecular markers (E-cadherin, N-cadherin, Vimentin). CONCLUSIONS High expression of lncRNA HOXA11-AS promotes breast cancer invasion and metastasis by affecting EMT, and interfering in lncRAN HOXA11-AS expression provides a theoretical basis and important molecular target for inhibiting the distant metastasis of breast cancer in clinical practice.

Drug repurposing in cancer

Cancer is a major health issue worldwide, and the global burden of cancer is expected to increase in the coming years. Whereas the limited success with current therapies has driven huge investments into drug development, the average number of FDA approvals per year has declined since the 1990s. This unmet need for more effective anti-cancer drugs has sparked a growing interest for drug repurposing, i.e. using drugs already approved for other indications to treat cancer. As such, data both from pre-clinical experiments, clinical trials and observational studies have demonstrated anti-tumor efficacy for compounds within a wide range of drug classes other than cancer. Whereas some of them induce cancer cell death or suppress various aspects of cancer cell behavior in established tumors, others may prevent cancer development. Here, we provide an overview of promising candidates for drug repurposing in cancer, as well as studies describing the biological mechanisms underlying their anti-neoplastic effects.

Strategies for obtaining bone biopsy specimens from breast cancer patients - Past experience and future directions

Background

Cancer and its treatment can have multiple effects on the bone. Despite the widespread use of in vivo and in vitro models, it is still necessary to understand these effects in humans. Obtaining human bone biopsies is technically challenging and in this article we review the experiences from the Ottawa Bone Oncology Program.

Methods

A series of bone biopsy studies in breast cancer patients with and without bone metastasis have been performed. We reviewed the results of these studies and present them in a descriptive manner. We discuss lessons learned from each project and how they have affected future directions for research.

Results

Since 2009, 5 studies have been performed accruing 97 breast cancer patients. Study endpoints have ranged from comparing the yield of malignant cells from CT-guided versus standard iliac crest biopsies, to studies assessing the feasibility of micro-CT analysis on Jedhadi trephines to evaluate bisphosphonate effects on bone micro-architecture. More recently, we have assessed the feasibility of performing repeat bone biopsies in the same patient as well as evaluating the practicality of obtaining bone tissue at the time of orthopaedic surgery.

Conclusion

Human bone tissue is an important biological resource. Our experience suggests that obtaining bone biopsies is feasible and can yield adequate amount of tumour cells for many studies. However, these remain technically challenging specimens to obtain and given the rapid advances in cancer therapeutics and the use of potent adjuvant bone-targeted agents, more centres need to be involved in these types of studies.

A phase 2 trial exploring the clinical and correlative effects of combining doxycycline with bone-targeted therapy in patients with metastatic breast cancer

Background

Bone-targeting agents (BTAs), such as bisphosphonates and denosumab, have demonstrated no discernable effects on tumour response or disease free/overall survival in patients with bone metastases from breast cancer. Doxycycline is both osteotropic and has anti-cancer effects. When combined with zoledronate in animal models, doxycycline showed significantly increased inhibition of tumour burden and increased bone formation. We evaluated the effects of adding doxycycline to ongoing anti-cancer therapy in patients with metastatic breast cancer.

Methods

Breast cancer patients with bone metastases and ≥3 months of BTA use, entered this single-arm study. Patients received doxycycline 100 mg orally, twice a day for 12 weeks. The co-primary endpoints were; effect on validated pain scores (FACT-Bone pain and Brief Pain Inventory) and bone resorption markers (serum C-telopeptide, [sCTx]). All endpoints (pain scores, sCTx, bone-specific alkaline phosphatase, skeletal-related events, toxicity) were evaluated at baseline, 4, 8 and 12 weeks. Bone marrow was sampled at baseline and week 12 for exploratory biomarker analysis.

Results

Out of 37 enroled patients, 27 (73%) completed 12 weeks of therapy. No significant changes were seen in pain scores or bone turnover markers. Failure to complete treatment: drug toxicity (70%) and disease progression (30%). Sixteen (43%) patients had GI adverse events.

Conclusions

Doxycycline 100 mg twice daily for 12 weeks had no significant effects on either bone pain or bone turnover markers. Its toxicity profile in this patient population would make further evaluation challenging.

A national portfolio of bone oncology trials-The Canadian experience in 2012

BACKGROUND

The impact of both cancer and its treatment on bone is an essential component of oncological practice. Bone oncology not only affects patients with both early stage and metastatic disease but also covers the entire spectrum of tumour types. We therefore decided to review and summarise bone oncology-related trials that are currently being conducted in Canada.

METHOD

We assessed ongoing and recently completed trials in Canada. We used available North American and Canadian cancer trial websites and also contacted known investigators in this field for their input.

RESULTS

Twenty seven clinical trials were identified. Seven pertained to local treatment of bone metastasis from any solid tumour type. Seven were systemic treatment trials, five focused on bone biology and predictive factors, three evaluated safety of bone-targeted agents, three were adjuvant trials and two trials investigated impact of cancer therapy on bone health. The majority of trials were related to systemic treatment and bone biology in breast cancer. Most were small, single centre, grant-funded studies. Not surprisingly the larger safety and adjuvant studies were pharmaceutical company driven.

DISCUSSION

Despite the widespread interest in bone-targeted therapies our survey would suggest that most studies are single centre and breast cancer focused. If major advances in bone oncology are to be made then collaborative strategies are needed to not only increase current sample sizes but to also expand these studies into non-breast cancer populations.