Metronomic chemotherapy and anti-angiogenesis: can upgraded pre-clinical assays improve clinical trials aimed at controlling tumor growth?

Docetaxel and 5-FU enhanced the inhibitory effects of apatinib and ramucirumab on growth and migration of gastric cancer

BACKGROUND

Gastric cancer (GC) is one of the most common malignant tumors in the world. The clinical benefit of anti-angiogenic strategy as a single drug is limited. Some studies showed that the combination of anti-angiogenic therapy and chemotherapy exhibited synergistic effect and reduced the side effects of chemotherapy drugs. We investigated the combined effects of these two types of drugs in gastric cancer cells in vitro and in vivo.

METHODS

cell viability, migration, invasion, and apoptosis were evaluated by CCK-8, wound-healing, transwell, and Annexin V-FITC/PI assay, respectively. In vivo anti-cancer efficacy was tested for the cell proliferation and metastasis in cell line derived tumor xenograft (CDX) model and patient derived tumor xenografted (PDX) model based on Tg (fli-1: EGFP) zebrafish embryos; RESULTS: In the cell experiments, the combination of the two types of drugs could inhibit the proliferation and metastasis of gastric cancer cells and promote apoptosis through VEGFR-2/AKT/ERK1/2 signal. In the zebrafish CDX (zCDX) model and zebrafish PDX (zPDX) model, the combination of the two treatment also showed a synergistic effect in inhibiting gastric cancer cell metastasis and cell proliferation.

CONCLUSIONS

Apatinib/ramucirumab targeted therapy combined with docetaxel or 5-fluorouracil (5-FU) may serve as an effective treatment strategy for patients with advanced gastric cancer.

The Spectrum of Histomorphological Changes and Pathological Tumor Response following Preoperative Oral Metronomic Chemotherapy in Oral Squamous Cell Carcinoma

Background Oral metronomic chemotherapy (OMCT) represents an emerging concept in cancer treatment involving frequent administration of chemotherapeutic drugs at doses below maximum tolerated doses and with no prolonged drug-free break. OMCT is being tried preoperatively in developing nations with constrained resources to prevent disease progression during the waiting period from diagnosis to surgery (bridge OMCT). The aim of the present study was to assess the spectrum of histomorphological changes and pathological tumor response following bridge OMCT in oral squamous cell carcinoma (OSCC) and to propose a new pathological response scoring system.

Materials and Methods A retrospective single-center study comprised of tissue sections of tumor proper and metastatic lymph nodes of 50, locally advanced OSCC patients treated with bridge OMCT, and had completed definitive surgery were analyzed. The present study evaluated the histomorphological features and proposed a new scoring system for pathologic tumor response. The pathologic tumor response was categorized as complete response (pCR), no response (pNR), and partial response (pPR).

Results Of the total 50 patients, 2 patients had pCR, 3 had pNR, and 45 patients had pPR as per the new proposed scoring system. Note that 96% of the cases showed no disease progression.

Conclusion Bridge OMCT is a novel treatment method that can be used to tide over the waiting period between the diagnosis and surgery in resource-constrained institutions with heavy patient load. This mode of treatment in locally advanced OSCC seems to provide promising results in this setting. Large multicentric trials are warranted to confirm these results.

Combination of metronomic administration and target delivery strategies to improve the anti-angiogenic and anti-tumor effects of triptolide

The metronomic administration of a low-dose cytotoxic agent with no prolonged drug-free breaks is an anti-angiogenic cancer treatment method. The use of nano-formulations in this manner enhances anti-tumor efficacy and reduces toxicity by inhibiting angiogenic activity, reduces adverse effects, and changes the biodistribution of TP in the body, steering TP away from potentially endangering healthy tissues. The present study uses liposomes and Asn-Gly-Arg (NGR) peptide conjugated aminopeptidase N(APN)-targeted liposomes for triptolide (TP), as a model for the investigation of targeted metronomic administration and subsequent effects on the toxicity profile and efficacy of the chemotherapeutic agent. Metronomic NGR-PEG-TP-LPs have been found to have enhanced anti-tumor activity, a phenomenon that is attributed to an increase in angiogenic inhibition properties. In vitro experiments demonstrate that the viability, migration, and tube formation of human umbilical vein endothelial cells (HUVECs) are obviously suppressed in comparison with that of other treatment groups. In vivo experiments also demonstrate that the anti-tumor efficacy of targeted metronomic administration is superior to that of liposome-administered treatments given at maximum tolerated dose (MTD) schemes, as is evidenced by markedly decreased tumor volume, vessel density, and the volume of circulating endothelial progenitor cells (CEPCs) in serum. Moreover, we observed that the metronomic administration of NGR-PEG-TP-LPs could elevate thrombospondin-1 (TSP-1) expression in tumors, a finding that is consistent with the promotion of TSP-1 secretion specifically from HUVECs. Additionally, metronomic NGR-PEG-TP-LPs have minimal drug-associated toxicity (weight loss, hepatotoxicity and nephrotoxicity in mice). Our research demonstrates the significance of targeted metronomic administration using liposomes for anti-angiogenic cancer therapy.

Liposome-Encapsulated Zoledronate Favors Tumor Vascular Normalization and Enhances Anticancer Efficacy of Cisplatin

The aim of this study was to examine the effectiveness of alanine-proline-arginine-proline-glycine (APRPG) peptide-conjugated PEGylated cationic liposomes-encapsulated zoledronic acid (ZOL) (APRPG-PEG-ZOL-CLPs) in achieving vascular normalization. Cisplatin (diamminedichloroplatinum, DDP) was used to improve anticancer efficacy. The present study showed that APRPG-PEG-ZOL-CLPs increased anticancer efficacy, which was regarded as vascular normalization. Our results demonstrated that the viability, migration, and tube formation of human umbilical vein endothelial cells (HUVECs) were evidently repressed by APRPG-PEG-ZOL-CLPs. Moreover, APRPG-PEG-ZOL-CLPs could decrease vessel density, as well as hypoxia-inducible factor 1α (HIF-1α), and increase thrombospondin 1 (TSP-1) expression of tumors. Therefore, the anticancer efficacy of APRPG-PEG-ZOL-CLPs combined with DDP was superior to that of PEG-ZOL-CLP or ZOL treatment combined with DDP schemes, as demonstrated by the obviously evident reduction in tumor volume. These results indicated that APRPG-PEG-ZOL-CLPs were most effective in normalizing tumor vasculature to elevate the therapeutic effect of antitumor drugs.

Dynamical analysis of tumor-immune-help T cells system

In this paper, we construct a mathematical model to investigate the interaction between the tumor cells, the immune cells and the helper T cells (HTCs). We perform mathematical analysis to reveal the stability of the equilibria of the model. In our model, the HTCs are stimulated by the identification of the presence of tumor antigens. Our investigation implies that the presence of tumor antigens may inhibit the existence of high steady state of tumor cells, which leads to the elimination of the bistable behavior of the tumor-immune system, i.e. the equilibrium corresponding to the high steady state of tumor cells is destabilized. Choosing immune intensity [Formula: see text] as bifurcation parameter, there exists saddle-node bifurcation. Besides, there exists a critical value [Formula: see text], at which a Hopf bifurcation occurs. The stability and direction of Hopf bifurcation are discussed.

The synergistic effects of Apatinib combined with cytotoxic chemotherapeutic agents on gastric cancer cells and in a fluorescence imaging gastric cancer xenograft model

Introduction

Methylsulfonic apatinib (hereinafter referred to as Apatinib) is a small-molecule angiogenesis inhibitor highly and selectively targeted to vascular endothelial growth factor receptor-2. At present, a series of basic and clinical studies have confirmed that Apatinib mono-therapy can inhibit the growth of different carcinomas. Our experiment aimed to determine whether there is a synergistic effect between the combination of the traditional cytotoxic chemotherapy drugs paclitaxel (TAX), oxaliplatin (L-OHP), 5-fluorouracil (5-FU), and Apatinib.

Materials and methods

We evaluated the combined effect using cytological experiments and a fluorescence imaging xenograft model. In vitro, the inhibition of cell proliferation increased notably when Apatinib was combined with TAX, L-OHP, and 5-FU. Then, for the mechanistic research, we selected the optimal dose of drugs that also had a synergistic effect. Apatinib combined with the aforementioned drugs, especially the combination of Apatinib and 5-FU, decreased the invasion and migration ability of the cells and increased the apoptosis ratio; expression of the anti-apoptotic protein Bcl-2 significantly decreased, and expression of the pro-apoptotic protein Bax increased. In vivo, when Apatinib was combined with TAX, L-OHP, and 5-FU, the volume of the xenograft model was significantly inhibited, the strength of the green fluorescence was weakened and the microvessel density decreased.

Results

The combination of Apatinib with TAX and 5-FU was synergistic (coefficient of drug interaction <1); the combination effect of Apatinib and L-OHP was only additive, with a shorter associated survival time.

Conclusion

The combination of Apatinib and classical chemotherapy drugs may be an optimal choice for gastric cancer treatment.

Metronomic and metronomic-like therapies in neuroendocrine tumors - Rationale and clinical perspectives

Metronomic therapy is characterized by the administration of regular low doses of certain drugs with very low toxicity. There have been numerous debates over the empirical approach of this regimen, but fewest side effects are always something to consider in order to improve patients' quality of life. Neuroendocrine tumors (NETs) are rare malignancies relatively slow-growing; therefore their treatment is often chronic, involving several different therapies for tumor growth control. Knowing that these tumors are highly vascularized, the anti-angiogenic aspect is highly regarded as something to be targeted in all patients harboring NETs. Additionally the metronomic schedule has proved to be effective on an immunological level, rendering this approach as a multi-targeted therapy. Rationalizing that advanced NETs are in many cases a chronic disease, with which patients can live for as long as possible, a systemic therapy with regular low doses and a very low toxicity is in many cases a judicious manner of pursuing stabilization. Metronomic schedule is usually correlated with chemotherapy in oncology, but other therapies, such as radiotherapy and biotherapy can be delivered in a metronomic like manner. This review describes clinical trials and case series involving metronomic therapies alone or in combination in patients with advanced NETs. Nowadays level of evidence about metronomic therapy in NETs is quite low, therefore future prospective clinical studies are needed to validate the metronomic approach in specific clinical settings.

An in vitro assessment of liposomal topotecan simulating metronomic chemotherapy in combination with radiation in tumor-endothelial spheroids

Low dose metronomic chemotherapy (LDMC) refers to prolonged administration of low dose chemotherapy designed to minimize toxicity and target the tumor endothelium, causing tumor growth inhibition. Topotecan (TPT) when administered at its maximum tolerated dose (MTD) is often associated with systemic hematological toxicities. Liposomal encapsulation of TPT enhances efficacy by shielding it from systemic clearance, allowing greater uptake and extended tissue exposure in tumors. Extended release of TPT from liposomal formulations also has the potential to mimic metronomic therapies with fewer treatments. Here we investigate potential toxicities of equivalent doses of free and actively loaded liposomal TPT (LTPT) and compare them to a fractionated low dose regimen of free TPT in tumor-endothelial spheroids (TES) with/without radiation exposure for a prolonged period of 10 days. Using confocal microscopy, TPT fluorescence was monitored to determine the accumulation of drug within TES. These studies showed TES, being more reflective of the in vivo tumor microenvironment, were more sensitive to LTPT in comparison to free TPT with radiation. More importantly, the response of TES to low-dose metronomic TPT with radiation was comparable to similar treatment with LTPT. This TES study suggests nanoparticle formulations designed for extended release of drug can simulate LDMC in vivo.

A systematic literature analysis of correlative studies in low-dose metronomic chemotherapy trials

Low-dose metronomic (LDM) chemotherapy is a beneficial and very well-tolerated form of chemotherapy utilization characterized by the frequent and uninterrupted administration of low doses of conventional chemotherapeutic agents over prolonged periods of time. While patients resistant to standard maximum tolerated dose (MTD) chemotherapy may still benefit from LDM chemotherapy, there is a lack of predictive markers of response to LDM chemotherapy. We searched the MEDLINE, EMBASE, CENTRAL and PubMed databases for correlative studies conducted as part of LDM chemotherapy trials in order to identify the most promising biomarker candidates. Given the antiangiogenic properties of LDM chemotherapy, angiogenesis-related biomarkers were most commonly studied. However, significant correlations between angiogenesis-related biomarkers and study end points were rare and variable, even so far as biomarkers correlating positively with an end point in some studies and negatively with the same end point in other studies. Pursuing biomarkers outside the angiogenesis field may be more promising.

Metronomic oral cyclophosphamide (MOC) in the salvage therapy of heavily treated recurrent ovarian cancer patients: a retrospective, multicenter study

BACKGROUND

The aim of this multicenter, retrospective study was to evaluate the efficacy and safety of metronomic oral cyclophosphamide (MOC) in heavily treated, relapsed ovarian cancer (ROC) patients.

METHODS

oral cyclophosphamide (Endoxan®, Baxter, Italy) was administered at the dose of 50 mg daily, continuously. Treatment-related toxicity and response to treatment were assessed by the NCI-CTC criteria, and RECIST criteria, respectively. Progression-free (PFS), and overall survival (OS) were also assessed.

RESULTS

54 patients were analyzed: 20 patients (37.0%) were considered primarily platinum refractory/resistant, while 34 patients (63.0%) were defined as platinum sensitive; 79.6% of patients had received ≥2 previous lines before starting MOC. The objective response rate (ORR) was 20.4%. Eleven patients (20.4%) experienced stable disease and 8 of them had a response duration ≥6 months. A total of 32 patients (59.2.%) progressed during treatment. Median PFS was 4 months, and the 12-month PFS rate was 19.6%; median OS was 13 months, and the 12-month OS rate was 51.5% . Patients responding to MOC showed a more favorable PFS (median = 17 months) compared to patients with stabilization (median = 6 months) or progression of disease (median = 3 months) (p value = 0.0001). Median OS of responding patients was 30 months compared to 11 months in cases achieving stabilization, or progression of disease (median = 8 months) (p value = 0.0001). Only 1 patient experienced grade 3 anemia. Non-hematological grade 3 toxicity was registered in 2 patients.

CONCLUSIONS

MOC could provide a valid alternative in terms of risk/benefit ratio in the palliative treatment of heavily treated ROC patients.