Bone effects of cancer therapies: pros and cons

Osteocytes: New Kids on the Block for Cancer in Bone Therapy

The tumor microenvironment plays a central role in the onset and progression of cancer in the bone. Cancer cells, either from tumors originating in the bone or from metastatic cancer cells from other body systems, are located in specialized niches where they interact with different cells of the bone marrow. These interactions transform the bone into an ideal niche for cancer cell migration, proliferation, and survival and cause an imbalance in bone homeostasis that severely affects the integrity of the skeleton. During the last decade, preclinical studies have identified new cellular mechanisms responsible for the dependency between cancer cells and bone cells. In this review, we focus on osteocytes, long-lived cells residing in the mineral matrix that have recently been identified as key players in the spread of cancer in bone. We highlight the most recent discoveries on how osteocytes support tumor growth and promote bone disease. Additionally, we discuss how the reciprocal crosstalk between osteocytes and cancer cells provides the opportunity to develop new therapeutic strategies to treat cancer in the bone.

Association between Quality of Life and Physical Functioning in a Gardening Intervention for Cancer Survivors

Purpose: To examine potential factors associated with maintaining or improving self-reported physical function (PF) among older cancer survivors participating in a gardening intervention impacted by the Coronavirus 2019 (COVID-19) pandemic. Methods: Thirty cancer survivors completed a home-based gardening intervention to encourage a healthier diet and a more active lifestyle. Device-based measures of physical activity (PA) and surveys to evaluate quality of life (QOL; PROMIS-57 questionnaire) were administered at baseline, mid-intervention (6 months), and post-intervention (9 months). Results: Depression, fatigue, and sleeplessness at baseline were significantly associated with worse average PF scores across follow-up (2.3 to 4.9 points lower for every decrease of 5 points in the QOL score; p-values < 0.02). Worsening of these QOL domains during the intervention was also associated with an additional decrease of 2.1 to 2.9 points in PF over follow-up (p values < 0.01). Better social participation and PA at baseline were significantly associated with better average PF scores during the intervention (2.8 to 5.2 points higher for every 5-point increase in social participation or 30 min more of PA; p values < 0.05). Every 5-point increase in pain at baseline, or increases in pain during the intervention, was associated with decreases of 4.9 and 3.0 points, respectively, in PF. Conclusions: Worse QOL scores before and during the intervention were significantly associated with worse PF over follow-up. Encouraging social participation and PA through interventions such as home-based gardening may improve long-term health among older cancer survivors.

Role of Osteocytes in Cancer Progression in the Bone and the Associated Skeletal Disease

PURPOSE OF REVIEW

The goal of this manuscript is to review the current knowledge on the role of osteocytes in cancer in the bone, discuss the potential of osteocytes as a therapeutic target, and propose future research needed to understand the crosstalk between cancer cells and osteocytes in the tumor niche.

RECENT FINDINGS

Numerous studies have established that cancer cells manipulate osteocytes to facilitate invasion and tumor progression in bone. Moreover, cancer cells dysregulate osteocyte function to disrupt physiological bone remodeling, leading to the development of bone disease. Targeting osteocytes and their derived factors has proven to effectively interfere with the progression of cancer in the bone and the associated bone disease. Osteocytes communicate with cancer cells and are also part of the vicious cycle of cancer in the bone. Additional studies investigating the role of osteocytes on metastases to the bone and the development of drug resistance are needed.

COX2 confers bone marrow stromal cells to promoting TNFα/TNFR1β-mediated myeloma cell growth and adhesion

PURPOSE

Bone marrow stromal cells (BMSCs) have been implicated in multiple myeloma (MM) progression. However, the underlying mechanisms remain largely elusive. Therefore, we aimed to explore key factors in BMSCs that contribute to MM development.

METHODS

RNA-sequencing was used to perform gene expression profiling in BMSCs. Enzyme-linked immunosorbent assays (ELISAs) were performed to determine the concentrations of PGE2 and TNFα in sera and conditioned media (CM). Western blotting, qRT-PCR and IHC were used to examine the expression of cyclooxygenase 2 (COX2) in BMSCs and to analyze the regulation of TNFα by COX2. Cell growth and adhesion assays were employed to explore the function of COX2 in vitro. A 5T33MMvt-KaLwRij mouse model was used to study the effects of COX2 inhibition in vivo.

RESULTS

COX2 was found to be upregulated in MM patient-derived BMSCs and to play a critical role in BMSC-induced MM cell proliferation and adhesion. Administration of PGE2 to CM derived from BMSCs promoted MM cell proliferation and adhesion. Conversely, inhibition of COX2 in BMSCs greatly compromised BMSC-induced MM cell proliferation and adhesion. PCR array-based analysis of inflammatory cytokines indicated that COX2 upregulates the expression of TNFα. Subsequent rescue assays showed that an anti-TNFα monoclonal antibody could antagonize COX2-mediated MM cell proliferation and adhesion. Administration of NS398, a specific COX2 inhibitor, inhibited in vivo tumor growth and improved the survival of 5TMM mice.

CONCLUSIONS

Our results indicate that COX2 contributes to BMSC-induced MM proliferation and adhesion by increasing the secretion of PGE2 and TNFα. Targeting COX2 in BMSCs may serve as a potential therapeutic approach of treating MM.

Standardized Uptake Value from Semiquantitative Bone Single-Photon Emission Computed Tomography/Computed Tomography in Normal Thoracic and Lumbar Vertebrae of Breast Cancer Patients

STUDY DESIGN

Retrospective study.

PURPOSE

This study aims to semiquantitatively evaluate the standardized uptake value (SUV) of 99mTc-methylene diphosphonate (MDP) radionuclide tracer in the normal vertebrae of breast cancer patients using an integrated single-photon emission computed tomography (SPECT)/computed tomography (CT) scanner.

OVERVIEW OF LITERATURE

Molecular imaging techniques using gamma cameras and stand-alone SPECT have traditionally been utilized to evaluate metastatic bone diseases. However, these methods lack quantitative analysis capabilities, impeding accurate uptake characterization.

METHODS

A total of 30 randomly selected female breast cancer patients were enrolled in this study. The SUV mean (SUVmean) and SUV maximum (SUVmax) values for 286 normal vertebrae at the thoracic and lumbar levels were calculated based on the patients' body weight (BW), body surface area (BSA), and lean body mass (LBM). Additionally, 106 degenerative joint disease (DJD) lesions of the spine were also characterized, and both their BW SUVmean and SUVmax values were obtained. A receiver operating characteristic (ROC) curve analysis was then performed to determine the cutoff value of SUV for differentiating DJD from normal vertebrae.

RESULTS

The mean±standard deviations for the SUVmean and SUVmax in the normal vertebrae displayed a relatively wide variability: 3.92±0.27 and 6.51±0.72 for BW, 1.05±0.07 and 1.75±0.17 for BSA, and 2.70±0.19 and 4.50±0.44 for LBM, respectively. Generally, the SUVmean had a lower coefficient of variation than the SUVmax. For DJD, the mean±standard deviation for the BW SUVmean and SUVmax was 5.26±3.24 and 7.50±4.34, respectively. Based on the ROC curve, no optimal cutoff value was found to differentiate DJD from normal vertebrae.

CONCLUSIONS

In this study, the SUV of 99mTc-MDP was successfully determined using SPECT/CT. This research provides an approach that could potentially aid in the clinical quantification of radionuclide uptake in normal vertebrae for the management of breast cancer patients.

Falls in older adults with cancer: an updated systematic review of prevalence, injurious falls, and impact on cancer treatment

PURPOSE

This update of our 2016 systematic review answers the following questions: (1) How often do older adults with cancer fall? (2) What are the predictors for falls? (3) What are the rates and predictors of injurious falls? (4) What are the circumstances and outcomes of falls? (5) How do falls in older patients affect subsequent cancer treatment? and a new research question, (6) Which fall reduction interventions are efficacious in this population?

METHODS

MEDLINE, PubMed, CINAHL, and Embase were searched (September 2015-January 25, 2019). Eligible studies included clinical trials and cohort, case-control, and cross-sectional studies published in English in which the sample (or subgroup) included adults aged ≥ 60, with cancer, in whom falls were examined as an outcome.

RESULTS

A total of 2521 titles were reviewed, 67 full-text articles were screened for eligibility, and 30 new studies were identified. The majority involved the outpatient setting (n = 19) utilizing cross-sectional method (n = 18). Sample size ranged from 21 to 17,958. Fall rates ranged from 1.52 to 3.41% per 1000 patient days (inpatient setting) and from 39%/24 months to 64%/12 months (outpatient setting). One out of the 6 research questions contributed to a new finding: one study reported that 1 in 20 older patients experienced impact on cancer treatment due to falls. No consistent predictors for falls/fall injuries and no studies on fall reduction interventions in the geriatric oncology setting were identified.

CONCLUSION

This updated review highlights a new gap in knowledge pertaining to interventions to prevent falls. Additionally, new knowledge also emerged in terms of impact of falls on cancer treatment; however, further research may increase generalizability. Falls and fall-related injuries are common in older adults with cancer and may affect subsequent cancer treatment. Further studies on predictors of falls, subsequent impacts, and fall reduction in the oncology setting are warranted.

Dose Issues in Cancer Chemotherapy

In this review, human methotrexate dosing regimens, as well as their relationship to data from in vitro cell culture and in vivo animal and human studies, are discussed. Low-dose, intermediate-dose, and high-dose therapies are covered. Since in vitro and in vivo screenings of potential cancer drugs are commonplace in the development of cancer chemotherapy, comparisons of the three criteria for effectiveness are important.

Does a Competing Risk Analysis Show Differences in the Cumulative Incidence of Revision Surgery Between Patients with Oncologic and Non-oncologic Conditions After Distal Femur Replacement?

BACKGROUND

Distal femur replacement is frequently used for limb salvage after bone tumor resections. It is also used in patients with severe bone loss because of traumatic conditions or revision TKA. Some studies on distal femur replacement reported on revision-free survival without distinguishing between patients with oncologic diagnoses and those without, although these patients might be incomparable because of their differences in important patient- and disease-specific characteristics. This may lead to an inaccurate and undifferentiated interpretation of the results of survival analyses.

QUESTIONS/PURPOSES

(1) What is the overall cumulative incidence of revision surgery after cemented and cementless distal femoral replacement, as determined with a competing risk analysis? (2) Does the cumulative incidence of revision surgery change over time? (3) Are there differences in the cumulative incidence of revision surgery between patients with oncologic conditions and those without who are treated with cemented or cementless distal femoral replacement?

METHODS

A total of 403 patients were possible candidates for distal femoral replacement. Of these, 56 patients elected to undergo different procedures, 83 were excluded because an expendable growing prosthesis was implanted, and 28 were lost to follow-up. Therefore, 229 patients who underwent distal femoral replacement for oncologic or non-oncologic reasons between 1983 and 2016 were retrospectively included in this study. The type of fixation method (cemented or cementless) was obtained from the patients' medical records, operation reports, and radiographic analyses from plain radiographs. All radiographs were standardized and obtained at standard time intervals in our institution. No algorithm regarding the fixation approach was followed. According to our data, patients receiving cementless fixation were younger and therefore likely to be more active than those receiving cemented fixation. The median follow-up duration of the overall cohort was 85 months (range 0.1-391 months). Patients who died or had revision surgery before the 2-year minimum follow-up interval were adequately considered using competing risk calculation. The reasons for revision surgery were classified using the classification system proposed by the International Society for Limb Salvage. A competing risk analysis was performed to estimate the cumulative incidence function of revision, accounting for death as a competing event. To evaluate the influence of potential prognostic factors, including diagnosis (oncologic versus non-oncologic), fixation (cemented versus cementless), year of distal femoral replacement, age, and sex on the occurrence of revision surgery, univariate and multivariable Fine and Gray models were applied.

RESULTS

The competing risks analysis revealed cumulative incidences of revision surgery for any cause (Types 1 to 5) of 26% (95% CI, 20.3%-31.9%) at 12 months, 37.9% (95% CI, 31.3%-44.4%) at 24 months, 52.6% (95% CI, 45.1%-59.5%) at 5 years, and 58.2% (95% CI, 50.1%-65.4%) at 10 years for all patients. Rotating hinge-type prostheses showed a lower cumulative incidence of revision surgery (41.6%; 95% CI, 31.8%-51%) than fixed-hinge prostheses did (64%; 95% CI, 50.5%-74.5% ) at 5 years (Gray's test: p = 0.01). According to the multivariate Fine and Gray model, the year of surgery did not have any effect on the risk of revision surgery (1994 to 2003: hazard ratio 0.70; 95% CI, 0.46-1.07); 2004 to 2016: HR 0.83; 95% CI, 0.52-1.34; p = 0.26). The multivariate analysis, adjusted for disease, sex, age, cementation, and year of surgery, revealed a difference in the risk of revision surgery between patients with oncologic disease and those with non-oncologic disease (HR 0.44 for oncologic versus non-oncologic; 95% CI, 0.22-0.87; p = 0.02) and a reduction in the risk of overall revision with cemented fixation in patients with oncologic disease (HR 0.53; 95% CI, 0.29-0.98; p = 0.03).

CONCLUSION

This study indicates that even with newer implants, there was a high incidence of revision surgery after distal femoral replacement. According to our analysis, patients with oncologic diagnoses have a lower likelihood of revision when the stem is cemented whereas the type of fixation did not impact patients with non-oncologic diagnoses. Because of differences in patient demographics (age, etiology of disease, and use of chemotherapy) and outcomes of fixation, oncologic and non-oncologic patients should be analyzed separately in survival studies about distal femoral replacement.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Ex Vivo Organ Cultures as Models to Study Bone Biology

The integrity of the skeleton is maintained by the coordinated and balanced activities of the bone cells. Osteoclasts resorb bone, osteoblasts form bone, and osteocytes orchestrate the activities of osteoclasts and osteoblasts. A variety of in vitro approaches has been used in an attempt to reproduce the complex in vivo interactions among bone cells under physiological as well as pathological conditions and to test new therapies. Most cell culture systems lack the proper extracellular matrix, cellular diversity, and native spatial distribution of the components of the bone microenvironment. In contrast, ex vivo cultures of fragments of intact bone preserve key cell-cell and cell-matrix interactions and allow the study of bone cells in their natural 3D environment. Further, bone organ cultures predict the in vivo responses to genetic and pharmacologic interventions saving precious time and resources. Moreover, organ cultures using human bone reproduce human conditions and are a useful tool to test patient responses to therapeutic agents. Thus, these ex vivo approaches provide a platform to perform research in bone physiology and pathophysiology. In this review, we describe protocols optimized in our laboratories to establish ex vivo bone organ cultures and provide technical hints and suggestions. In addition, we present examples on how this technical approach can be employed to study osteocyte biology, drug responses in bone, cancer-induced bone disease, and cross-talk between bone and other organs © 2020 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

A Practical Guide to Geriatric Syndromes in Older Adults With Cancer: A Focus on Falls, Cognition, Polypharmacy, and Depression

Geriatric syndromes are multifactorial conditions that are prevalent in older adults. Geriatric syndromes are believed to develop when an individual experiences accumulated impairments in multiple systems that compromise their compensatory ability. In older adults with cancer, the presence of a geriatric syndrome is common and may increase the complexity of cancer treatment. In addition, the physiologic stress of cancer and cancer treatment may precipitate or exacerbate geriatric syndromes. Common geriatric syndromes include falls, cognitive syndromes and delirium, depression, and polypharmacy. In the oncology setting, the presence of geriatric syndromes is relevant; falls and cognitive problems have been shown to be predictive of chemotherapy toxicity and overall survival. Polypharmacy and depression are more common in older adults with cancer compared with the general geriatric population. Multiple screening tools exist to identify falls, cognitive problems, polypharmacy, and depression in older adults and can be applied to the oncology setting to identify patients at risk. When recognized, several interventions exist that could be considered for this vulnerable population. We review the available evidence of four geriatric syndromes in the oncology setting, including clinical implications, validated screening tools, potential supportive care, and therapeutic interventions.

Aplidin (plitidepsin) is a novel anti-myeloma agent with potent anti-resorptive activity mediated by direct effects on osteoclasts

Despite recent progress in its treatment, Multiple Myeloma (MM) remains incurable and its associated bone disease persists even after complete remission. Thus, identification of new therapeutic agents that simultaneously suppress MM growth and protect bone is an unmet need. Herein, we examined the effects of Aplidin, a novel anti-cancer marine-derived compound, on MM and bone cells. In vitro, Aplidin potently inhibited MM cell growth and induced apoptosis, effects that were enhanced by dexamethasone (Dex) and bortezomib (Btz). Aplidin modestly reduced osteocyte/osteoblast viability and decreased osteoblast mineralization, effects that were enhanced by Dex and partially prevented by Btz. Further, Aplidin markedly decreased osteoclast precursor numbers and differentiation, and reduced mature osteoclast number and resorption activity. Moreover, Aplidin reduced Dex-induced osteoclast differentiation and further decreased osteoclast number when combined with Btz. Lastly, Aplidin alone, or suboptimal doses of Aplidin combined with Dex or Btz, decreased tumor growth and bone resorption in ex vivo bone organ cultures that reproduce the 3D-organization and the cellular diversity of the MM/bone marrow niche. These results demonstrate that Aplidin has potent anti-myeloma and anti-resorptive properties, and enhances proteasome inhibitors blockade of MM growth and bone destruction.

Cancer Metastases to Bone: Concepts, Mechanisms, and Interactions with Bone Osteoblasts

The skeleton is a unique structure capable of providing support for the body. Bone resorption and deposition are controlled in a tightly regulated balance between osteoblasts and osteoclasts with no net bone gain or loss. However, under conditions of disease, the balance between bone resorption and deposition is upset. Osteoblasts play an important role in bone homeostasis by depositing new bone osteoid into resorption pits. It is becoming increasingly evident that osteoblasts additionally play key roles in cancer cell dissemination to bone and subsequent metastasis. Our laboratory has evidence that when osteoblasts come into contact with disseminated breast cancer cells, the osteoblasts produce factors that initially reduce breast cancer cell proliferation, yet promote cancer cell survival in bone. Other laboratories have demonstrated that osteoblasts both directly and indirectly contribute to dormant cancer cell reactivation in bone. Moreover, we have demonstrated that osteoblasts undergo an inflammatory stress response in late stages of breast cancer, and produce inflammatory cytokines that are maintenance and survival factors for breast cancer cells and osteoclasts. Advances in understanding interactions between osteoblasts, osteoclasts, and bone metastatic cancer cells will aid in controlling and ultimately preventing cancer cell metastasis to bone.

Risk of low bone mineral density in testicular germ cell cancer survivors: association with hypogonadism and treatment modality

The cure rate of testicular cancer exceeds 95%, but testicular cancer survivors (TCS) are at increased risk of hypogonadism (HG). It has been suggested that TCS have reduced bone mineral density (BMD), but it is unclear whether this is related to HG or a direct effect of cancer therapy. The aim of this study was to evaluate whether TCS have decreased BMD, and if BMD is related to HG and/or the cancer treatment given. We investigated 91 TCS (mean age at diagnosis: 31 years; mean 9.3 years follow-up) and equal number of age matched controls (mean age at inclusion 40.3 years and 41.2 years, respectively). Total testosterone and LH were measured. BMD was determined using dual-energy X-ray absorptiometry (DXA). Low BMD (LBD) was defined as Z-score <-1. Compared to eugonadal TCS, both TCS with untreated HG (mean difference: -0.063 g/cm² ; 95% CI: -0.122; -0.004 p = 0.037) and TCS receiving androgen replacement (mean difference -0.085 g/cm² ; 95% CI: -0.168; -0.003; p = 0.043) presented with statistically significantly 6-8% lower hip BMD. At the spine, L1-L4, an 8% difference reached the level of statistical significance only for those with untreated HG (mean difference: -0.097 g/cm² ; 95% CI: -0.179; -0.014; p = 0.022). TCS with untreated HG had significantly increased OR for spine L1-L4 LBD (OR = 4.1; 95% CI: 1.3; 13; p = 0.020). The associations between the treatment given and BMD were statistically non-significant, both with and without adjustment for HG. In conclusion, TCS with HG are at increased risk of impaired bone health. Prevention of osteoporosis should be considered as an important part in future follow up of these men.

Genetic deletion of Sost or pharmacological inhibition of sclerostin prevent multiple myeloma-induced bone disease without affecting tumor growth

Multiple myeloma (MM) causes lytic bone lesions due to increased bone resorption and concomitant marked suppression of bone formation. Sclerostin (Scl) levels, an osteocyte-derived inhibitor of Wnt/β-catenin signaling, are elevated in MM patient sera and are increased in osteocytes in MM-bearing mice. We show here that genetic deletion of Sost, the gene encoding Scl, prevented MM-induced bone disease in an immune-deficient mouse model of early MM, and that administration of anti-Scl antibody (Scl-Ab) increased bone mass and decreases osteolysis in immune-competent mice with established MM. Sost/Scl inhibition increased osteoblast numbers, stimulated new bone formation and decreased osteoclast number in MM-colonized bone. Further, Sost/Scl inhibition did not affect tumor growth in vivo or anti-myeloma drug efficacy in vitro. These results identify the osteocyte as a major contributor to the deleterious effects of MM in bone and osteocyte-derived Scl as a promising target for the treatment of established MM-induced bone disease. Further, Scl did not interfere with efficacy of chemotherapy for MM suggesting that combined treatment with anti-myeloma drugs and Scl-Ab should effectively control MM growth and bone disease, providing new avenues to effectively control MM and bone disease in patients with active MM.

Bone metastasis: the importance of the neighbourhood

During the past decade preclinical studies have defined many of the mechanisms used by tumours to hijack the skeleton and promote bone metastasis. This has led to the development and widespread clinical use of bone-targeted drugs to prevent skeletal-related events. This understanding has also identified a critical dependency between colonizing tumour cells and the cells of bone. This is particularly important when tumour cells first arrive in bone, adapt to their new microenvironment and enter a long-lived dormant state. In this Review, we discuss the role of different bone cell types in supporting disseminated tumour cell dormancy and reactivation, and highlight the new opportunities this provides for targeting the bone microenvironment to control dormancy and bone metastasis.

Mortality in cancer patients after a fall-related injury: The impact of cancer spread and type

BACKGROUND

Cancer patients are at an increased risk of dying following an injury, of which among the elderly is predominately caused by falling. In addition, patients with certain types of cancer are more prone to bone injury. However, studies are needed that examine the role of cancer site and metastasis on the relationship between cancer and death following traumatic injury.

METHODS

A total of 4201 cancer patients from 2000 to 2009 in the Illinois Hospital Discharge and Illinois Trauma Registry, and 4201 patients without cancer met eligibility criteria (e.g., fell and were injured; 50-96 years old). A multivariable logistic regression analysis was conducted to assess the relationship between cancer and death following traumatic injury, including models stratified by cancer site and metastasis.

RESULTS

The demographic characteristics, prevalence of comorbid conditions, and injury severity and type did not differ substantially between patients with and without diagnoses for cancer. In the main adjusted model, patients with cancer were more likely to die during the course of hospitalization after a fall than those without cancer (OR=2.58; CI 95%: 1.91-3.49). Patients with metastatic malignancies had a higher risk of in-hospital death than patients without metastasis (adjusted OR=3.59 and OR=2.18, respectively). Patients with diagnoses for all specific cancer sites, except prostate and breast, were also significantly more likely to die.

DISCUSSION

Cancer patients with and without spread over the age of 50 years are more likely to die in-hospital after a fall than elderly patients without cancer. However, this relationship may exist only for patients with specific cancer types.

A Kunitz-type FXa inhibitor affects tumor progression, hypercoagulable state and triggers apoptosis

Cancer is linked to hypercoagulability, and many studies have shown that anticoagulant drugs affect tumor progression. In this study was demonstrated that the Amblyomin-X (which is a recombinant protein that exerts similarity to the Kunitz-type inhibitors and shows pro-apoptotic effects in different tumor cell lines) and heparin (a classic anticoagulant) have similar effects on cancer progression and on normalization of the hypercoagulable state. However, Amblyomin-X showed a distinct mechanism in triggering its effects in vitro, because it exerted a cytotoxic effect in cancer cells by inducing apoptosis and promoting cell cycle arrest.