Potential effect of chloroquine and propranolol combination to treat colorectal and triple-negative breast cancers

Drug repositioning explores the reuse of non-cancer drugs to treat tumors. In this work, we evaluated the effect of the combination of chloroquine and propranolol on colorectal and triple-negative breast cancers. Using as in vitro models the colorectal cancer cell lines HCT116, HT29, and CT26, and as triple-negative breast cancer models the 4T1, M-406, and MDA-MB-231 cell lines, we evaluated the effect of the drugs combination on the viability, apoptosis, clonogenicity, and cellular migratory capacity. To explore the in vivo effects of the combination on tumor growth and metastasis development we employed graft models in BALB/c, nude, and CBi mice. In vitro studies showed that combined treatment decreased cell viability in a dose-dependent manner and increased apoptosis. Also, we demonstrated that these drugs act synergically and that it affects clonogenicity and migration. In vivo studies indicated that this drug combination was effective on colorectal models but only partially on breast cancer. These results contributed to the search for new and safe treatments for colorectal and triple-negative carcinomas.

Abstract P3-07-61: Predictors of response and follow up biomarkers for metronomic chemotherapy with cyclophosphamide and celecoxib in advanced breast cancer patients

Low-dose metronomic chemotherapy (MC) with Cyclophosphamide (Cy) and Celecoxib (Cel) has demonstrated to be effective and well-tolerated in advanced breast cancer patients (ABCP) but predictive markers of response or follow-up are lacking. Given the antiangiogenic properties of MC we analyzed several angiogenesis-related biomarkers and evaluated their potential role as predictors of response or treatment follow-up of ABCP treated with MC. Treatment plan: Patients received Cy 50 mg p.o./day + Cel 200 mg p.o./ bid. Cellular parameters: Circulating endothelial cells (CEC) and Circulating progenitor endothelial Cells (CEP) were determined by Flow Cytometry. Serologic parameters: Serum levels of vascular endothelial growth factor (VEGF), VEGF-C, soluble VEGF Receptors 2 and 3 (sVEGFR-2, sVEGFR-3) and Thrombospondin-1 (TSP-1) were determined by ELISA. Blood samples were collected before and during treatment. Twenty patients were enrolled. Response Rate was 5% and Clinical Benefit (CB) 55%. Most of the patients showed prolonged stable disease (SD≥24 weeks). Biomarkers were determined in all patients. Levels of CEC and CEP showed no clear trend variations during treatment. However, levels of CEC significantly increased at the time of disease progression in those patients who showed CB (P=0.014). Also baseline values of CEC and CEP showed marginally significant associations withTime To Progression. Serum VEGF concentration decreased during treatment (P=0.050) while sVEGFR-2 increased (P=0.005). VEGF-C, sVEGFR-3 and TSP-1 showed non-significant variations. VEGF/sVEGFR-2 ratio decreased during treatment (P=0.041), whereas VEGF/TSP-1, and VEGF-C/sVEGFR-2 ratios showed non-significant variations. Baseline values of VEGF, and VEGF/sVEGFR-2 showed negative and significant associations with TTP (P=0.0354 and P=0.0300, respectively) while sVEGFR-2 did not. When considering the two variables together, the goodness of prediction was not improved. To confirm the value of baseline VEGF and VEGF/sVEGFR-2 as predictors of response, we used the 50th percentile as a cutoff value to analyze the % of progression free survival. Patients with values lower than the 50th percentile for both biomarkers showed longer TTP (P=0.0001 and P=0.0008, respectively). The treatment had anti-angiogenic effect (VEGF decrease and sVEGFR-2 increase). The absence of variation in VEGF-C and sVEGFR-3 would indicate the lack of effect on lymphangiogenesis. Increased levels of CEC could be useful for detecting progression. If confirmed with a higher number of patients, baseline VEGF and VEGF/sVEGFR-2 values could be useful as early predictors of response.

Citation Format: Perroud HA, Alasino CM, Rico MJ, Menacho-Marquez MA, Mainetti LE, Queralt F, Pezzotto SM, Rozados VR, Scharovsky G. Predictors of response and follow up biomarkers for metronomic chemotherapy with cyclophosphamide and celecoxib in advanced breast cancer patients. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-61.

Association between baseline VEGF/sVEGFR-2 and VEGF/TSP-1 ratios and response to metronomic chemotherapy using cyclophosphamide and celecoxib in patients with advanced breast cancer

BACKGROUND

Metronomic chemotherapy (MCT) with cyclophosphamide (Cy) and celecoxib (Cel) has therapeutic efficacy and low toxicity profile in advanced breast cancer patients (ABCP), but no reliable biomarkers of response have been found yet that allow patient selection for treatment.

AIM

To investigate the potential role as biomarkers of pro- and antiangiogenic parameters and evaluate their response in ABCP receiving metronomic Cy 50 mg p.o./day + Cel 400 mg p.o./day.

MATERIALS AND METHODS

Serum levels of vascular endothelial growth factor-C (VEGF-C), soluble VEGF receptors 2 and 3 (sVEGFR-2, sVEGFR-3), were measured at different time points in 13/15 patients included in a phase II trial of MCT with Cy+Cel.

RESULTS

Serum levels of sVEGFR-2 and sVEGFR-3 increased significantly during treatment (P = 0.0392; P = 0.0066, respectively). VEGF-C showed no significant modifications. Previous determinations of VEGF and TSP-1 in the same patients were utilized. VEGF/sVEGFR-2, VEGF/TSP-1, and VEGF-C/sVEGFR-3 ratios decreased significantly along the treatment (P = 0.0092; P = 0.0072; P = 0.0141, respectively). Nonsignificant variations were observed for VEGF-C/sVEGFR-2 ratio. Baseline values of VEGF/sVEGFR-2 and VEGF/TSP-1 ratios were associated with time to progression (TTP) (P = 0.0407; P = 0.0394, respectively) meanwhile baseline VEGF was marginally significant (P = 0.0716). Patients with values lower than the 50th percentile for both ratios showed longer TTP.

CONCLUSIONS

We have identified the baseline VEGF/sVEGFR-2 and VEGF/TSP-1 ratios as potential biomarkers of response in ABCP treated metronomically with Cy+Cel. This finding warrants its confirmation in a higher number of patients.

Comparative effectiveness of two metronomic chemotherapy schedules-our experience in the preclinical field

Metronomic chemotherapy refers to the chronic, equally spaced, delivery of low doses of chemotherapeutic drugs, without extended interruptions. Previously, we developed two combined metronomic schemes for the treatment of murine mammary tumors. The aim of this study was to compare their effects on tumor and metastasis growth, survival, and toxicity. Metronomic chemotherapy with Cyclophosphamide + Celecoxib (Cy + Cel) showed higher antimetastatic power than Cyclophosphamide + Doxorubicin (Cy + Dox), while being similar in other aspects. That difference, plus the advantage that represents its oral administration, suggests that the Cy + Cel combination is more suitable than Cy + Dox for metronomic chemotherapy of mammary tumors and could be proposed to the translation to the clinic.

Therapeutic efficacy of metronomic chemotherapy with cyclophosphamide and doxorubicin on murine mammary adenocarcinomas

BACKGROUND

Metronomic chemotherapy (MCT) refers to the chronic and equally spaced administration of low doses of different chemotherapy drugs, without extended rest periods. Herein, we investigated the therapeutic efficacy of metronomic cyclophosphamide (Cy) combined with doxorubicin (Dox) in two mouse mammary adenocarcinoma models.

MATERIALS AND METHODS

Mice were s.c. challenged with M-234p or M-406 mammary tumors, and when the tumors reached ∼150 mm(3), they were treated with: (I) no treatment (controls); (II) Cy in the drinking water (30 mg/kg body weight/day); (III) Dox (0.5 mg/kg body weight i.p. three times/week); (IV) treated as (II) + (III). Mice challenged i.v. with M-234p or M-406 tumor cells received, on day 3, the same treatments.

RESULTS

We found that MCT with Cy plus Dox inhibited tumor growth, decreased lung metastases, and increased the median survival time, while having low toxic effect. Combined MCT was more effective than each monotherapy causing decrease in VEGF serum concentration and tumor proliferation rate plus increase in tumor apoptosis.

CONCLUSION(S)

The therapeutic benefits of combined MCT with Cy and Dox on mammary adenocarcinomas together with its low toxic effect profile suggest the possibility of future translation into the clinic.

Regulatory T cells but not NKT I cells are modulated by a single low-dose cyclophosphamide in a B cell lymphoma tumor-model

AIM

Experimental and clinical studies showed that the administration of cyclophosphamide (Cy) in low doses leads to an enhancement of the antitumor immune response. Our objective was to study the modulation, if any, by low dose Cy, of T regulatory (Treg) and natural killer T (NKT) I cells, two cell populations of the innate immune response with opposing effects on the tumors, in a rat B cell lymphoma model.

METHODS

Inbred e rats were challenged s.c. with L-TACB lymphoma and on day 14 animals were distributed in two groups. Treated: injected i.p. with cyclophosphamide (10mg/kg of body weight) and

CONTROL

injected i.p. with saline. Blood samples were taken from days 0 to 21 and the percentage of T regulatory and natural killer T I cells were determined by flow cytometry.

RESULTS

We found that the increase of natural and inducible T regulatory cells of peripheral blood achieved during tumor growth was significantly downregulated by cyclophosphamide. On the contrary, natural killer T I cells were not modulated by the treatment.

CONCLUSION

The antimetastatic effect of a single low dose of Cy would be due, at least in part, to downregulation of natural and inducible T regulatory cells.

Metronomic chemotherapy: changing the paradigm that more is better

The introduction of the "maximum tolerated dose" in usual treatment protocols (and its concomitant overt toxicity) made necessary the imposition of rest periods between cycles of therapy-a practice that not only involves re-growth of tumour cells, but also growth of selected clones resistant to the therapy. To avoid the problems caused by traditional chemotherapeutic regimens, a new modality of drug administration called "metronomic chemotherapy" has been proposed. This name makes reference to the chronic, equally spaced administration of (generally) low doses of various chemotherapeutic drugs without extended rest periods. The novelty of this treatment modality lies not only in its antitumour efficacy with very low toxicity, but also in a cell target switch, now aiming at tumour endothelial cells. The knowledge acquired in the experimental field of metronomic chemotherapy, plus the increasing experience that is being obtained in the clinical setting, will help to lead a change in the design of therapeutic protocols against cancer.

Abstract P2-16-11: Metronomic Chemotherapy with Cyclophosphamide (CY) and Doxorubicin (DOX) Inhibits Tumor Growth and Metastases Development of Mouse Mammary Adenocarcinoma M-406

Metronomic chemotherapy refers to the chronic, equally spaced, deliver of low doses of different chemotherapeutic drugs, without extended interruptions. We have already demonstrated that the administration, as an intervention strategy, of metronomic CY plus Celecoxib in M-406 and M-234p mammary adenocarcinomas-bearing mice, inhibited tumor growth and metastases development, increasing the survival rate. Our present aim was to study the effect of metronomic chemotherapy with CY + DOX in the M-406 tumor-model. CBi inbred mice were s.c. and i.v. challenged with M-406 cells. On day 9 (s.c.) and day 3 (i.v.), mice were distributed in four experimental groups (n=5-6/group) that received: I) Control: 0.2ml of saline i.p. 3 times/week; II) CY (20mg/kg of body weight, daily) in the drinking water; III) Dox, i.p., 0,5mg/kg, of body weight, 3 times/week; IV) Treatment II + III. Tumors were measured and body weight was determined twice a week. Blood samples were taken at the beginning and at the end of the experiments, to determine total leukocytes count. In the M-406 s.c. model, by day 19, a significant inhibition of tumor growth was evident in group II and IV with respect to control mice (P<0.01). Moreover, on day 41 the tumor volume of animals in group IV was significantly lower than that in group II. Also in group IV, 1 mouse over 6 showed a complete remission. The survival of mice in group IV was significantly higher than in the three other groups. In fact, on day 54, when all the animals belonging to groups I, II and III had already died, 5/6 mice in group IV were alive. In the M-406 i.v. model, animals were sacrificed on day 24 when the first mouse showed metastatic illness signs. The number of lung metastasis was significantly lower in group IV when compared to the control group (P<0.05). The animals in groups II and III (with single-drug treatments) showed intervening values. The total metastatic volume (Σeach metastasis volume) in groups II, III and IV was lower than that of group I (P<0.01), the group IV showing the lowest one. In both experiments (s.c. and i.v.) the treatment was devoid of toxicity, as evaluated by body weight evolution and, importantly, by total leukocytes count. These results clearly show that metronomic chemotherapy with a combination of cyclophosphamide and doxorubicin as an intervention strategy is able to inhibit significantly tumor growth and metastasis development in the M-406 mammary adenocarcinoma tumor-model, while being devoid of toxicity. To our knowledge, this is the first time that a metronomic schedule combining cyclophosphamide and doxorubicin is employed for the treatment of a mammary adenocarcinoma. The characteristics and the effect of the therapeutic schedule herein utilized suggest its implementation at the clinical setting in the near future.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-16-11.

Lovastatin enhances in vitro radiation-induced apoptosis of rat B-cell lymphoma cells

Our previous demonstration of an antimetastatic effect of lovastatin, both in rat sarcoma and lymphoma tumor-models, as well as the fact that lovastatin and radiation are able to stop the cell cycle in different phases, suggested the feasibility of a combined treatment. We studied the effect of the in vitro combined treatment of a B-cell rat lymphoma (L-TACB) with lovastatin and irradiation. The results herein obtained provide new information about the role of statins as radiosensitizers. The antitumor effect of the combined treatment was higher than that elicited by either treatment alone. This effect could be a consequence, at least in part, of an enhanced apoptosis.

Metronomic therapy with cyclophosphamide induces rat lymphoma and sarcoma regression, and is devoid of toxicity

BACKGROUND

Our aim was to investigate the clinical efficacy and toxicity of metronomic administration of low-dose cyclophosphamide (Cy) in lymphoma and sarcoma rat tumour models.

METHODS

Adult inbred rats were challenged with lymphoma TACB and sarcoma E100 s.c. on day 0. Animals were divided into two groups: group I, control, injected with saline three times a week; and group II, treated with Cy 10 mg/kg three times a week, from day 10 until the tumour was non-palpable, or 5 mg/kg three times a week from day 7. Tumours were measured and animals were weighed twice weekly. Periodic blood samples were taken for determination of urea, creatinine, serum glutamic-oxaloacetic transaminase, lactate dehydrogenase and haematological parameters.

RESULTS

The administration of low-dose Cy eradicated established rat lymphomas and sarcomas; there was neither metastatic growth nor recurrence at primary sites for 100% of the lymphomas and 83% of the sarcomas. In addition, the treatment did not cause weight loss, and was devoid of haematological, cardiac, hepatic and renal toxicity.

CONCLUSIONS

Metronomic administration of Cy at low doses on a thrice weekly schedule to already grown rat lymphomas and sarcomas demonstrated itself to be a successful antitumour therapy that did not cause weight loss and was devoid of haematological, cardiac, hepatic and renal toxicity.

Down regulation of T-cell-derived IL-10 production by low-dose cyclophosphamide treatment in tumor-bearing rats restores in vitro normal lymphoproliferative response

In previous reports, we demonstrated an inhibitory effect of a single low-dose of cyclophosphamide (Cy) on spontaneous and experimental metastasis of a rat lymphoma (L-TACB). This antimetastatic effect could be adoptively transferred by immune spleen cells from Cy-treated tumor-bearing rats and it was abrogated by the use of immunosuppressed hosts, suggesting an immunomodulatory effect. Subsequently, we found that increased levels of TGF-beta, IL-10 and NO were involved in tumor-induced immunosuppression by inhibiting lymphocyte proliferation. The treatment of tumor-bearing rats with low-dose Cy reduced the splenic production of these suppressive cytokines, restoring the lymphoproliferative capacity otherwise diminished during tumor growth. Here, we investigated the changes of the cytokines modulated by the Cy therapy that are responsible for the restoration of the lymphoproliferative response and determined the spleen cell type producing TGF-beta, IL-10 and NO in our experimental model. Our current results show that IL-10 and NO are produced exclusively by T lymphocytes and macrophages, respectively, whereas TGF-beta is produced by both cell types. The high level of IL-10 produced by T-cells from tumor-bearing rats is responsible for the inhibition of lymphocyte proliferation. Moreover, our results suggest that the shift from immunosuppression to immunopotentiation induced by treatment of tumor-bearing rats with a single low-dose of Cy is mediated by a reduction in T-cell derived IL-10 production, which would account, to some extent, for the antimetastatic effect of Cy treatment.

Modulation of the antimetastatic effect of a single low dose of cyclophosphamide on rat lymphoma

The aim of this paper was to identify the mechanism/s responsible of the antimetastatic effect of a single low dose of cyclophosphamide (Cy), previously demonstrated by us in the rat lymphoma LTACB. No direct cytotoxic antimetastatic activity of Cy could be proved. In vitro treatment of L-TACB cells with mafosfamide did not alter their invasiveness or their motility. The adoptive transfer of splenocytes from Cy-treated tumor-bearing rats, together with L-TACB cells inhibited their metastatic growth. The single low dose Cy treatment of T-immunodeficient nude mice did not show the antimetastatic effect on L-TACB observed in immunocompetent mice. An inhibition of the metastatic ability due to immunomodulation by Cy is proposed.

Inhibition of ras oncogene: a novel approach to antineoplastic therapy

The most frequently detected oncogene alterations, both in animal and human cancers, are the mutations in the ras oncogene family. These oncogenes are mutated or overexpressed in many human tumors, with a high incidence in tumors of the pancreas, thyroid, colon, lung and certain types of leukemia. Ras is a small guanine nucleotide binding protein that transduces biological information from the cell surface to cytoplasmic components within cells. The signal is transduced to the cell nucleus through second messengers, and it ultimately induces cell division. Oncogenic forms of p21(ras) lead to unregulated, sustained signaling through downstream effectors. The ras family of oncogenes is involved in the development of both primary tumors and metastases making it a good therapeutic target. Several therapeutic approaches to cancer have been developed pointing to reducing the altered gene product or to eliminating its biological function: (1) gene therapy with ribozymes, which are able to break down specific RNA sequences, or with antisense oligonucleotides, (2) immunotherapy through passive or active immunization protocols, and (3) inhibition of p21(ras) farnesylation either by inhibition of farnesyl transferase or synthesis inhibition of farnesyl moieties.

Inhibition of ras oncogene: a novel approach to antineoplastic therapy

The most frequently detected oncogene alterations, both in animal and human cancers, are the mutations in the ras oncogene family. These oncogenes are mutated or overexpressed in many human tumors, with a high incidence in tumors of the pancreas, thyroid, colon, lung and certain types of leukemia. Ras is a small guanine nucleotide binding protein that transduces biological information from the cell surface to cytoplasmic components within cells. The signal is transduced to the cell nucleus through second messengers, and it ultimately induces cell division. Oncogenic forms of p21(ras) lead to unregulated, sustained signaling through downstream effectors. The ras family of oncogenes is involved in the development of both primary tumors and metastases making it a good therapeutic target. Several therapeutic approaches to cancer have been developed pointing to reducing the altered gene product or to eliminating its biological function: (1) gene therapy with ribozymes, which are able to break down specific RNA sequences, or with antisense oligonucleotides, (2) immunotherapy through passive or active immunization protocols, and (3) inhibition of p21(ras) farnesylation either by inhibition of farnesyl transferase or synthesis inhibition of farnesyl moieties.

Mechanism of antimetastatic immunopotentiation by low-dose cyclophosphamide

We have previously reported the antimetastatic effect of a single low-dose of cyclophosphamide (Cy) on L-TACB rat lymphoma. The phenomenon could be adoptively transferred in immunocompetent rats and is abolished in nude mice, facts for which an immunomodulatory explanation was proposed. The aim of this paper was to identify the mechanism(s) by which spleen cells from Cy-treated tumour-bearing rats could exert this antimetastatic activity. Conditioned media obtained by incubation of spleen cells from Cy-treated and non-treated tumour-bearing rats, under specific or non-specific stimulation, were assayed to evaluate their effect on lymphocyte proliferation. The production of transforming growth factor beta (TGF-beta), interleukin-10 (IL-10) and nitric oxide (NO) by conditioned media was also studied. The restoration of spleen lymphoproliferative responses to normal levels when exposed to media conditioned by splenocytes from Cy-treated tumour-bearing rats, together with a decreased production of suppressive cytokines TGF-beta, IL-10 and NO, suggest an enhancement of host antimetastatic immunity triggered by single low-dose Cy treatment.

Inhibitory effect of Lovastatin on spontaneous metastases derived from a rat lymphoma

The HMGCoA reductase inhibitor Lovastatin (LOV) has previously shown to abrogate p21ras farnesylation, which is associated with invasive and metastatic abilities in many tumor models. Considering the scarcity of therapeutic resources against metastasis, our objective was to study LOV as an antimetastatic agent on L-TACB rat lymphoma, which as a syngeneic tumor model resembles more closely the situation in human cancer. We also aimed to analyze the effect of LOV on chemoinvasion, motility, metalloproteases secretion, angiogenic capacity, and adhesion to the reconstituted basement membrane Matrigel. Our results showed that LOV caused no effect on cell motility, metalloprotease secretion and neovascularization. Conversely, LOV produced a significant inhibition of invasiveness, which could be a consequence of an impaired cell adhesion to the basement membrane observed. These effects could explain, at least in part, the inhibitory action of LOV on L-TACB rat lymphoma metastases.

Lovastatin inhibits tumor growth and metastasis development of a rat fibrosarcoma

HMG-CoA (3-hydroxy-3-methylglutaryl coenzyme A) reductase, the rate limiting enzyme in cholesterol synthesis, catalyses mevalonate production and, hence, influence the synthesis of isoprenoid metabolites. It has already been demonstrated that products of the mevalonate pathway play an important role in the progress of the cell cycle and cell survival. Lovastatin (LOV) competitively inhibits HMG-CoA reductase, blocking the synthesis of mevalonic acid and the generation of non-sterol isoprenoids, such as farnesyl residues. The posttranslational farnesylation of p21ras protein is essential for its binding to the membrane and, therefore, for its transforming activity. Considering that p21ras protein was reported to have a significant rol in metastatic behavior of tumor cells, we decided to study LOV as an antimetastatic agent on a rat fibrosarcoma. We demonstrated that a short treatment with LOV diminished primary tumor growth and the number and size of lung experimental metastasis.