Activity of mevalonate pathway inhibitors against breast and ovarian cancers in the ATP-based tumour chemosensitivity assay

BTNL9 is frequently downregulated and inhibits proliferation and metastasis via the P53/CDC25C and P53/GADD45 pathways in breast cancer

Breast cancer (BC) threatens the life and health of women worldwide because of its high morbidity and mortality. The present study aimed to explore the biological functions and potential mechanism of BTNL9 in BC. RNA sequence and clinical data extracted from the Kaplan-Meier plotter database and The Cancer Genome Atlas (TCGA) were utilized to analyze the relationship between the expression level of BTNL9 in BC tissues and clinicopathological features and the effects of BTNL9 expression on the prognosis of BC. The diagnostic efficacy of BTNL9 expression was estimated by receiver operating characteristic (ROC) curve analysis. The mRNA and protein expression levels of BTNL9 in BC cell lines and in BC tissue were determined by quantitative real-time PCR (qPCR) and western blotting, respectively. The functions of BTNL9 were measured by colony formation, CCK-8, Transwell, flow cytometry and EdU assays. Western blotting analysis was also performed to explore the latent mechanism of BTNL9. The results showed that the expression of BTNL9 declined in BC tissues and cell lines. Low expression of BTNL9 was significantly associated with early progression of T stage, relapse-free survival (RFS), and poor overall survival (OS). Ectopic expression of BTNL9 inhibited cell proliferation, colony formation and metastasis and induced apoptosis in BC, while knockdown of BTNL9 had the opposite result. Furthermore, BTNL9 blocked BC cells in the G2/M phase via the P53/CDC25C and P53/GADD45 pathways. Our results suggest that BTNL9 may play a tumor-suppressive role in BC and has the potency to become a new biomarker for early BC diagnosis.

Statins as adjuvants in the treatment of ovarian cancer: Controversy and misunderstanding

Ovarian cancer is frequently detected in advanced stages when the chances of survival are very low. Although chemotherapy is the treatment of choice, it is often rapidly compromised by the development of chemoresistance in patients. There are few pharmacological alternatives for managing chemoresistant ovarian cancer and statins have been suggested as an alternative, but their use is considered controversial. We present an overview of the most relevant epidemiological, in vitro and in vivo studies on the effects of statins in mono- or polytherapy for ovarian cancer. We conclude that the negative or inconclusive results of some epidemiological studies on statin-based cancer treatment are probably due, in large part, to the low doses given to patients, equivalent to those prescribed for hypercholesterolemia. Higher concentrations are well tolerated in animal models and by most patients in clinical trials. Future research is necessary to explore this possibility.

Recycling the Purpose of Old Drugs to Treat Ovarian Cancer

The main challenge in ovarian cancer treatment is the management of recurrences. Facing this scenario, therapy selection is based on multiple factors to define the best treatment sequence. Target therapies, such as bevacizumab and polymerase (PARP) inhibitors, improved patient survival. However, despite their achievements, ovarian cancer survival remains poor; these therapeutic options are highly costly and can be associated with potential side effects. Recently, it has been shown that the combination of repurposed, conventional, chemotherapeutic drugs could be an alternative, presenting good patient outcomes with few side effects and low costs for healthcare institutions. The main aim of this review is to strengthen the importance of repurposed drugs as therapeutic alternatives, and to propose an in vitro model to assess the therapeutic value. Herein, we compiled the current knowledge on the most promising non-oncological drugs for ovarian cancer treatment, focusing on statins, metformin, bisphosphonates, ivermectin, itraconazole, and ritonavir. We discuss the primary drug use, anticancer mechanisms, and applicability in ovarian cancer. Finally, we propose the use of these therapies to perform drug efficacy tests in ovarian cancer ex vivo cultures. This personalized testing approach could be crucial to validate the existing evidences supporting the use of repurposed drugs for ovarian cancer treatment.

Butyrophilin-Like 9 (BTNL9) Suppresses Invasion and Correlates with Favorable Prognosis of Uveal Melanoma

Background

Uveal melanoma (UM) is the most common intraocular malignancy, and the prognosis of patients with advanced stage of UM is very dismal. The T cell receptor ectopic expression of butyrophilin-like 9 (BTNL9) has been observed in several types of cancers, but the expression and clinical significance of BTNL9 in UM is unclear.

Material/Methods

In our study, we detected the expression of BTNL9 in 6 pairs of UM tissues and adjacent tissues using quantitative real-time polymerase chain reaction (qRT-PCR), and further investigated BTNL9 expression with immunohistochemistry (IHC) in a retrospective cohort consisted of 62 UM patients. The correlations between BNTL9 expression and clinicopathological factors were analyzed with Fisher’s test, and the prognostic significance of BTNL9 was evaluated with univariate analysis and multivariate analysis. Using experiments in vitro, we investigated the function of BTNL9 in UM proliferation and invasion.

Results

BTNL9 mRNAs in adjacent tissues were remarkably higher than in UM tissues. The percentages of BTNL9 low expression and high expression were 56.45% and 43.55%, respectively. High expression of BTNL9 was significantly associated with favorable prognosis of UM. BTNL9 expression was identified as a prognostic biomarker predicting better outcome of UM patients. Moreover, BTNL9 could suppress invasion instead of proliferation in melanoma cell line.

Conclusions

BTNL9 was a favorable prognostic factor of UM and it could suppress invasion of UM, suggesting that BTNL9 detection could help stratify high-risk patients with UM after operation and guide more precise surveillance and treatment.

Bisphosphonates and Cancer: A Relationship Beyond the Antiresorptive Effects

Bisphosphonates (BPs) are stable analogues of the Inorganic Pyrophosphate (PPi), an endogenous regulator of bone mineralization, which can resist the hydrolysis in the gastrointestinal tract. Their conformation allows targeting the bone as a result of their three-dimensional structure, which makes them primary agents against osteoclast-mediated bone loss. They are used in many bone pathological conditions, like bone metastasis, because of its ability to modulate bone metabolism into a less favorable place to cancer cell growth, through the inhibition of osteoclastogenesis and bone resorption. This review is focused on the mechanisms of action through which BPs affect the cellular activity and survival, mainly on their antitumoral effects. In conclusion, BPs are considered the primary therapy for skeletal disorders due to its high affinity for bone, but now they are also considered as potential antitumor agents due to its ability to induce tumor cell apoptosis, inhibition of cell adhesion, invasion and proliferation, modulation of the immune system to target and eliminate cancer cells as well as affect the angiogenic mechanisms. Like any other drug, they also have some adverse effects, but the most common, the acute phase reaction, can be minimized with the intake of calcium and vitamin D.

Butyrophilin3A proteins and Vγ9Vδ2 T cell activation

Despite playing critical roles in the immune response and having significant potential in immunotherapy, γδ T cells have garnered little of the limelight. One major reason for this paradox is that their antigen recognition mechanisms are largely unknown, limiting our understanding of their biology and our potential to modulate their activity. One of the best-studied γδ subsets is the human Vγ9Vδ2T cell population, which predominates in peripheral blood and can combat both microbial infections and cancers. Although it has been known for decades that Vγ9Vδ2T cells respond to the presence of small pyrophosphate-based metabolites, collectively named phosphoantigens (pAgs), derived from microbial sources or malignant cells, the molecular basis for this response has been unclear. A major breakthrough in this area came with the identification of the Butyrophilin 3A (BTN3A) proteins, members of the Butyrophilin/Butyrophilin-like protein family, as mediators between pAgs and Vγ9Vδ2T cells. In this article, we review the most recent studies regarding pAg activation of human Vγ9Vδ2T cells, mainly focusing on the role of BTN3A as the pAg sensing molecule, as well as its potential impact on downstream events of the activation process.

Synergistic Antiproliferative Effects of Zoledronic Acid and Fluvastatin on Human Pancreatic Cancer Cell Lines: An in Vitro Study

Bisphosphonates and statins are known to have antitumor activities against different types of cancer cell lines. In the present study, we investigated the antiproliferative effects of the combination of zoledronic acid (ZOL), a bisphophosphonate, and fluvastatin (FLU), a statin, in vitro on two types of human pancreatic cancer cell lines, Mia PaCa-2 and Suit-2. The pancreatic cancer cell lines were treated with ZOL and FLU both individually and in combination to evaluate their antiproliferative effects using WST-8 cell proliferation assay. In this study, we demonstrated a potent synergistic antiproliferative effect of both drugs when used in combination in both cell lines. Moreover, we studied the molecular mechanism behind this synergistic effect, which was inhibited by the addition of the mevalonate pathway products, farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP). Furthermore, we aimed to determine the effect of ZOL and FLU combination on RhoA and Ras guanosine 5'-triphosphate (GTP)-proteins. The combination induced a marked accumulation in RhoA and unprenylated Ras. GGPP and FPP reversed the increase in the amount of both proteins. These results indicated that the combination treatment impaired RhoA and Ras signaling pathway by the inhibition of geranylgeranylation and/or farnesylation. This study provides a potentially effective approach for the treatment of pancreatic cancer using a combination treatment of ZOL and FLU.

A Designed Inhibitor of p53 Aggregation Rescues p53 Tumor Suppression in Ovarian Carcinomas

Half of all human cancers lose p53 function by missense mutations, with an unknown fraction of these containing p53 in a self-aggregated amyloid-like state. Here we show that a cell-penetrating peptide, ReACp53, designed to inhibit p53 amyloid formation, rescues p53 function in cancer cell lines and in organoids derived from high-grade serous ovarian carcinomas (HGSOC), an aggressive cancer characterized by ubiquitous p53 mutations. Rescued p53 behaves similarly to its wild-type counterpart in regulating target genes, reducing cell proliferation and increasing cell death. Intraperitoneal administration decreases tumor proliferation and shrinks xenografts in vivo. Our data show the effectiveness of targeting a specific aggregation defect of p53 and its potential applicability to HGSOCs.

Rac1/Pak1/p38/MMP-2 Axis Regulates Angiogenesis in Ovarian Cancer

PURPOSE

Zoledronic acid is being increasingly recognized for its antitumor properties, but the underlying functions are not well understood. In this study, we hypothesized that zoledronic acid inhibits ovarian cancer angiogenesis preventing Rac1 activation.

EXPERIMENTAL DESIGN

The biologic effects of zoledronic acid were examined using a series of in vitro [cell invasion, cytokine production, Rac1 activation, reverse-phase protein array, and in vivo (orthotopic mouse models)] experiments.

RESULTS

There was significant inhibition of ovarian cancer (HeyA8-MDR and OVCAR-5) cell invasion as well as reduced production of proangiogenic cytokines in response to zoledronic acid treatment. Furthermore, zoledronic acid inactivated Rac1 and decreased the levels of Pak1/p38/matrix metalloproteinase-2 in ovarian cancer cells. In vivo, zoledronic acid reduced tumor growth, angiogenesis, and cell proliferation and inactivated Rac1 in both HeyA8-MDR and OVCAR-5 models. These in vivo antitumor effects were enhanced in both models when zoledronic acid was combined with nab-paclitaxel.

CONCLUSIONS

Zoledronic acid has robust antitumor and antiangiogenic activity and merits further clinical development as ovarian cancer treatment.

Purinergic signalling and cancer

Receptors for extracellular nucleotides are widely expressed by mammalian cells. They mediate a large array of responses ranging from growth stimulation to apoptosis, from chemotaxis to cell differentiation and from nociception to cytokine release, as well as neurotransmission. Pharma industry is involved in the development and clinical testing of drugs selectively targeting the different P1 nucleoside and P2 nucleotide receptor subtypes. As described in detail in the present review, P2 receptors are expressed by all tumours, in some cases to a very high level. Activation or inhibition of selected P2 receptor subtypes brings about cancer cell death or growth inhibition. The field has been largely neglected by current research in oncology, yet the evidence presented in this review, most of which is based on in vitro studies, although with a limited amount from in vivo experiments and human studies, warrants further efforts to explore the therapeutic potential of purinoceptor targeting in cancer.

The effect of bisphosphonates on the risk of endometrial and ovarian malignancies

OBJECTIVE

The use of bisphosphonates has been associated with reduced risk and improved survival of breast and colorectal malignancies. This study was aimed at studying the effects of bisphosphonates on gynecological cancers.

METHODS

The Cancer in the Ovary and Uterus Study (CITOUS) is a case-control study of newly diagnosed cases of gynecological malignancies and age/clinic/ethnic-group matched population controls. The use of bisphosphonates prior to, and following, diagnosis was assessed in 424 cases of ovarian and endometrial cancers and 341 controls, all postmenopausal at recruitment, enrolled in Clalit Health Services (CHS), using pharmacy records.

RESULTS

The use of bisphosphonates for more than 1 year prior to diagnosis was associated with a significantly reduced risk of ovarian cancer (OR=0.49, 95% CI: 0.26-0.93) and endometrial cancer (OR=0.39, 95% CI: 0.24-0.63). The association with endometrial cancer (OR=0.48, 0.27-0.84) remained statistically significant after adjustment for a variety of putative effect modifiers (RR=0.48, 0.26-0.89). The association with ovarian cancer remained significant when adjusted to statin use (0.46, 0.23-0.90) but not for other modifiers (0.58, 0.29-1.18). A strong negative association was found in an adjusted model for the use of either bisphosphonates or statins for more than 1 year (0.40, 0.23-0.68).

CONCLUSION

The use of bisphosphonates, with or without statins, for more than 1 year before diagnosis was associated with reduced risk of endometrial and ovarian cancers.

Designing personalised cancer treatments

The concept of personalised medicine for cancer is not new. It arguably began with the attempts by Salmon and Hamburger to produce a viable cellular chemosensitivity assay in the 1970s, and continues to this day. While clonogenic assays soon fell out of favour due to their high failure rate, other cellular assays fared better and although they have not entered widespread clinical practice, they have proved to be very useful research tools. For instance, the ATP-based chemosensitivity assay was developed in the early 1990s and is highly standardised. It has proved useful for evaluating new drugs and combinations, and in recent years has been used to understand the molecular basis of drug resistance and sensitivity to anti-cancer drugs. Recent developments allow unparalleled genotyping and phenotyping of tumours, providing a plethora of targets for the development of new cancer treatments. However, validation of such targets and new agents to permit translation to the clinic remains difficult. There has been one major disappointment in that cell lines, though useful, do not often reflect the behaviour of their parent cancers with sufficient fidelity to be useful. Low passage cell lines - either in culture or xenografts are being used to overcome some of these issues, but have several problems of their own. Primary cell culture remains useful, but large tumours are likely to receive neo-adjuvant treatment before removal and that limits the tumour types that can be studied. The development of new treatments remains difficult and prediction of the clinical efficacy of new treatments from pre-clinical data is as hard as ever. One lesson has certainly been that one cannot buck the biology - and that understanding the genome alone is not sufficient to guarantee success. Nowhere has this been more evident than in the development of EGFR inhibitors. Despite overexpression of EGFR by many tumour types, only those with activating EGFR mutations and an inability to circumvent EGFR blockade have proved susceptible to treatment. The challenge is how to use advanced molecular understanding with limited cellular assay information to improve both drug development and the design of companion diagnostics to guide their use. This has the capacity to remove much of the guesswork from the process and should improve success rates.

The role of master regulators in the metabolic/transcriptional coupling in breast carcinomas

Metabolic transformations have been reported as involved in neoplasms survival. This suggests a role of metabolic pathways as potential cancer pharmacological targets. Modulating tumor's energy production pathways may become a substantial research area for cancer treatment. The significant role of metabolic deregulation as inducing transcriptional instabilities and consequently whole-system failure, is thus of foremost importance. By using a data integration approach that combines experimental evidence for high-throughput genome wide gene expression, a non-equilibrium thermodynamics analysis, nonlinear correlation networks as well as database mining, we were able to outline the role that transcription factors MEF2C and MNDA may have as main master regulators in primary breast cancer phenomenology, as well as the possible interrelationship between malignancy and metabolic dysfunction. The present findings are supported by the analysis of 1191 whole genome gene expression experiments, as well as probabilistic inference of gene regulatory networks, and non-equilibrium thermodynamics of such data. Other evidence sources include pathway enrichment and gene set enrichment analyses, as well as motif comparison with a comprehensive gene regulatory network (of homologue genes) in Arabidopsis thaliana. Our key finding is that the non-equilibrium free energies provide a realistic description of transcription factor activation that when supplemented with gene regulatory networks made us able to find deregulated pathways. These analyses also suggest a novel potential role of transcription factor energetics at the onset of primary tumor development. Results are important in the molecular systems biology of cancer field, since deregulation and coupling mechanisms between metabolic activity and transcriptional regulation can be better understood by taking into account the way that master regulators respond to physicochemical constraints imposed by different phenotypic conditions.

Skeletal remodeling following clinically relevant radiation-induced bone damage treated with zoledronic acid

Our aim was to determine if zoledronic acid (ZA) changes (45)Ca pharmacokinetics and bone microstructure in irradiated, ovary-intact (I) and irradiated, ovariectomized mice (OVX), two groups with different patterns of skeletal damage. The hind limbs of I and OVX BALB/c mice received a single 16-Gy radiation dose, simulating pre- and postmenopausal female cancer patients undergoing radiation treatment. All I and OVX mice were radiolabeled with 15 μCi (45)Ca. Mice were treated with or without a 0.5 mg/kg injection of ZA. The time course of bone mineral remodeling was evaluated using a fecal (45)Ca assay, measured by liquid scintillation. A group of nonirradiated, intact mice were used for the longitudinal evaluation of (45)Ca biodistribution. Distal femur bone histomorphometric parameters were measured using microCT at 50 days post-ZA intervention. Most (45)Ca was incorporated into the skeleton and eliminated from the soft tissues within 3-5 days postirradiation, attaining a steady state of excretion at 25-30 days. ZA intervention in both groups resulted in a rapid decrease in fecal (45)Ca excretion. There was a significant difference in (45)Ca excretion in the OVX ± ZA (P = 0.005) group but not in the I ± ZA (P = 0.655) group. The rate of excretion of fecal (45)Ca was slower in the OVX + ZA compared to the I + ZA group (P = 0.064). (45)Ca assay is useful to monitor the time course of bone mineral remodeling after an antiresorptive intervention in irradiated mice, providing a basis to investigate bone effects of cancer therapy protocols. For equivalent doses of ZA, recovery may depend on the nature and degree of skeletal damage.

The potential application of zoledronic acid as anticancer therapy in patients with non-small-cell lung cancer

Non-small-cell lung cancer (NSCLC) is frequently characterized by metastases to bone. Bisphosphonates have demonstrated efficacy in reducing the risk of skeletal-related events in cancer patients with bone metastases, including those with NSCLC. Zoledronic acid (ZA) is one of the most potent bisphosphonates and is approved for the first-line treatment of patients with multiple myeloma and bone metastases from solid tumors. Recent preclinical and clinical data suggest that ZA may also have direct and indirect anticancer effects. Several preclinical studies have provided insight into the potential mechanisms responsible for the anticancer activity of ZA, including inhibiting farnesyl pyrophosphate or geranylgeranyl pyrophosphate and activation of immune-mediated anticancer response by γδ T cells. In patients with NSCLC, ZA has been shown to reduce vascular endothelial growth factor levels with a direct correlation to clinical response. Clinical studies in this setting have shown that ZA may also provide a survival benefit and prolong time to progression. Ongoing studies are evaluating the efficacy of ZA for anticancer activity and prevention of bone metastases. Bisphosphonates, particularly ZA, are generally well tolerated and may likely offer an adjunct therapeutic option for patients with NSCLC.

Cell sensitivity assays: the ATP-based tumor chemosensitivity assay

The ATP-based tumor chemosensitivity assay (ATP-TCA) is a standardised system which can be adapted to a variety of uses with both cell lines and primary cell cultures. It has a strong track record in drug development, mechanistic studies of chemoresistance and as an aid to clinical decision-making. The method starts with the extraction of cells in suspension from continuous cell culture (for cell lines), malignant effusions or biopsy material. Enzymatic digestion is used to obtain cells from tumor tissue. The assay uses a serum-free medium and polypropylene plates to prevent the growth of non-neoplastic cells over a 6-day incubation period followed by detergent-based extraction of cellular ATP for measurement by luciferin-luciferase assay in a luminometer. The assay results are usually shown as percentage inhibition at each concentration tested, and can be used with suitable software to examine synergy between different anticancer agents.

ATP chemosensitivity testing of new antitumor duplex drugs linking 3`-C-ethynylycytidine (ECyd) and 2´-deoxy-5-fluorouridine (5-FdU) in comparison to standard cytostatica and combinations thereof

BACKGROUND

2´-Deoxy-5-fluorouridylyl-(5´-5´)-3´-C-ethynylcytidine [5-FdU(5´-5´)ECyd] and 3´-C-ethynylcytidinylyl-(5´->1-O)-2-O-octadecyl-sn-glycerylyl-(3-Ο->5´)-2´-deoxy-5-fluorouridine [ECyd-lipid-5-FdU] are antitumor active duplex drugs and these heterodinucleoside phosphate analogues could be cleaved in vivo by wide-spread phosphodiesterases into different antitumor active antimetabolites.

METHODS

We cultured breast MCF-7, MDA-MB-231 and ovarian OVCAR-29 and OAW-42 cancer cell lines and used the luminometric measuring of the ATP tumor chemosensitivity assay to assess the in vitro activity of 5-FdU(5´-5´)ECyd and ECyd-lipid-5-FdU in comparison to standard single cytostatic agents and combinations thereof currently used in anticancer therapies. To allow comparison between samples and different regimens IndexSUM was determined based on the percentage tumor cell growth inhibition at each test drug concentration. Additionally, the cytostatic efficacy of 5-FdU(5´-5´)ECyd and ECyd-lipid-5-FdU was evaluated at a minimum of five concentrations at 10 fold dilutions using 60 human tumor cell lines including ovarian and breast cancer cell lines from the National Cancer Institute (USA).

RESULTS

5-FdU(5´-5´)ECyd and ECyd-lipid-5-FdU have a high cytostatic efficacy reaching 50% tumor cell growth inhibition at concentrations ranging between nano- and micomolar. IndexSum values for broad range efficacy in MCF-7 breast cancer cells were comparable to values obtained for standard drug combinations. Higher cytostatic efficacy was observed in MDA-MB-231 cells.

CONCLUSION

The duplex drugs 5-FdU(5´-5´)ECyd and ECyd-lipid-5-FdU represent potential new chemotherapeutic drugs for breast and ovarian cancer cells which are comparable to currently used drug combinations and more potent in comparison to some monocytostatica used in cancer therapy.

A single pretreatment by zoledronic acid converts metastases from osteolytic to osteoblastic in the rat

Bone metastases are severe complications of cancers associated with increased morbidity, pain, risk fracture, and reduced life span for patients. Bisphosphonates emerged as a relief treatment in bone metastases. A single dose of zoledronic acid (78 microg/kg) was injected into six Copenhagen rats 4 days before receiving an intraosseous inoculation of metastatic anaplastic tumor of lymph node and lung cell (MLL) prostate cancer cells. Rat femurs were analyzed for changes by microCT and histomorphometry; trabecular volume, trabecular characteristics, osteoid parameters, osteoblastic surfaces, and osteoclast number were measured. Values were compared to a group of SHAM animals, a group of SHAM animals having received zoledronic acid and animals inoculated with MLL cells. All rats were euthanized after 1 month. MLL cells induced osteolysis in the metaphysis with extension of the tumor to soft tissues through cortical perforations. Zoledronic acid induced a marked osteosclerosis in the primary spongiosa in both SHAM and rats inoculated with MLL. Osteosclerosis was obtained in the secondary spongiosa of MLL rats. The bisphosphonate preserved cortical integrity in all animals, and no extension to soft tissues was observed in most animals. The number of osteoclasts was elevated, indicating that there was no apoptosis of osteoclasts but they became inactive. Osteosclerosis was associated with increased osteoblastic surfaces. A single zoledronic acid injection turned osteolytic metastases into osteosclerotic and preserved cortical integrity.