Cisplatin plus paclitaxel and maintenance of bevacizumab on tumour progression, dissemination, and survival of ovarian carcinoma xenograft models

Targeting VEGF with bevacizumab inhibits malignant effusion formation of primary human herpesvirus 8‐unrelated effusion large B‐cell lymphoma in vivo

Primary human herpesvirus 8 (HHV8)‐unrelated effusion large B‐cell lymphoma (ELBCL) is recognized as a new clinical entity, but its pathogenesis and therapeutic strategies remain largely unknown. We have generated two mouse models with profuse lymphomatous effusions that resemble HHV8‐unrelated ELBCL occurring in humans, by grafting the cell lines designated as Pell‐1 and Pell‐2. Using these in vivo models, we evaluated the potential role of vascular endothelial growth factor (VEGF) in the pathogenesis of HHV8‐unrelated ELBCL. Both Pell‐1 and Pell‐2 cells consistently produced very high levels of VEGF in mice, in contrast to in vitro findings of relatively low VEGF production in culture medium by HHV8‐unrelated ELBCL cells, especially Pell‐1 cells. Conversely, returning Pell‐1 cells grown in mice to culture medium markedly suppressed VEGF production to the original in vitro level. These findings suggest that the tumour microenvironment plays a role in the steady production of VEGF. We also found that the interaction between HHV8‐unrelated ELBCL cells and peritoneal mesothelial cells increased the production of VEGF in vitro. Finally, we found that bevacizumab significantly suppressed effusion formation and lymphoma cell growth in both mouse models. These results suggest that bevacizumab is a rational approach to the treatment of HHV8‐unrelated ELBCL.

Cancer combination therapies by angiogenesis inhibitors; a comprehensive review

Abnormal vasculature is one of the most conspicuous traits of tumor tissue, largely contributing to tumor immune evasion. The deregulation mainly arises from the potentiated pro-angiogenic factors secretion and can also target immune cells' biological events, such as migration and activation. Owing to this fact, angiogenesis blockade therapy was established to fight cancer by eliminating the nutrient and oxygen supply to the malignant cells by impairing the vascular network. Given the dominant role of vascular-endothelium growth factor (VEGF) in the angiogenesis process, the well-known anti-angiogenic agents mainly depend on the targeting of its actions. However, cancer cells mainly show resistance to anti-angiogenic agents by several mechanisms, and also potentiated local invasiveness and also distant metastasis have been observed following their administration. Herein, we will focus on clinical developments of angiogenesis blockade therapy, more particular, in combination with other conventional treatments, such as immunotherapy, chemoradiotherapy, targeted therapy, and also cancer vaccines. Video abstract.

PGC1α/β Expression Predicts Therapeutic Response to Oxidative Phosphorylation Inhibition in Ovarian Cancer

Ovarian cancer is the deadliest gynecologic cancer, and novel therapeutic options are crucial to improve overall survival. Here we provide evidence that impairment of oxidative phosphorylation (OXPHOS) can help control ovarian cancer progression, and this benefit correlates with expression of the two mitochondrial master regulators PGC1α and PGC1β. In orthotopic patient-derived ovarian cancer xenografts (OC-PDX), concomitant high expression of PGC1α and PGC1β (PGC1α/β) fostered a unique transcriptional signature, leading to increased mitochondrial abundance, enhanced tricarboxylic acid cycling, and elevated cellular respiration that ultimately conferred vulnerability to OXPHOS inhibition. Treatment with the respiratory chain complex I inhibitor IACS-010759 caused mitochondrial swelling and ATP depletion that consequently delayed malignant progression and prolonged the lifespan of high PGC1α/β-expressing OC-PDX-bearing mice. Conversely, low PGC1α/β OC-PDXs were not affected by IACS-010759, thus pinpointing a selective antitumor effect of OXPHOS inhibition. The clinical relevance of these findings was substantiated by analysis of ovarian cancer patient datasets, which showed that 25% of all cases displayed high PGC1α/β expression along with an activated mitochondrial gene program. This study endorses the use of OXPHOS inhibitors to manage ovarian cancer and identifies the high expression of both PGC1α and β as biomarkers to refine the selection of patients likely to benefit most from this therapy.

SIGNIFICANCE

OXPHOS inhibition in ovarian cancer can exploit the metabolic vulnerabilities conferred by high PGC1α/β expression and offers an effective approach to manage patients on the basis of PGC1α/β expression.

The DNA-PK inhibitor AZD7648 sensitizes patient derived ovarian cancer xenografts to pegylated liposomal doxorubicin and olaparib preventing abdominal metastases

Ovarian cancer is the deadliest gynaecological cancer, with a 5 year survival rate of 30%, when the disease has spread throughout the peritoneal cavity. We investigated the efficacy to delay disease progression by the DNA-dependent protein kinase (DNA-PKcs)inhibitor AZD7648, administered in combination with two of the therapeutic options for patient management: either pegylated liposomal doxorubicin (PLD) or the poly(adenosine diphosphate-ribose)polymerase (PARP) inhibitor olaparib. Patient-derived ovarian cancer xenografts (OC-PDXs) were transplanted subcutaneously to evaluate the effect of treatment on tumour growth, or orthotopically in the peritoneal cavity to evaluate the effect on metastatic spread. AZD7648 was administered orally (po)in combination with PLD (dosed intravenously) or with olaparib (po). To prove the inhibition of DNA-PK in the tumours, we measured pDNA-PKcs, pRPA32 and γH2AX, biomarkers of DNA-PK activity. AZD7648 enhanced the therapeutic efficacy of PLD in all the OC-PDXs tested, regardless of their BRCA status, sensitivity to cisplatin or PLD. The treatment caused disease stabilization, that persisted despite therapy discontinuation for tumours growing subcutaneously, and significantly impaired the abdominal metastatic dissemination, prolonging the lifespan of mice implanted orthotopically. AZD7648 potentiated the efficacy of olaparib in BRCA-deficient OC-PDXs, but did not sensitize BRCA-proficient OC-PDXs to olaparib, despite an equivalent inhibition of DNA-PK, suggesting the need of a pre-existing olaparib activity to benefit from the addition of AZD7648. This work suggests that AZD7648, an inhibitor of DNA-PK, dosed in combination with PLD or olaparib is an exciting therapeutic option that could benefit ovarian cancer patients and should be explored in clinical trials.

Targeted therapy of angiogenesis using anti-VEGFR2 and anti-NRP-1 nanobodies

PURPOSE

Targeted therapy in cancer researches is a promising approach that can resolve drawbacks of systematic therapeutics. Nanobodies are potent therapeutics due to their high specificity and affinity to the target.

METHODS

In this study, we evaluated the effect of the combination of anti-vascular endothelial growth factor receptor 2 (anti-VEGFR2) and anti-neuropilin-1 (anti-NRP1) nanobodies both in vitro (MTT, and tube formation assay) and in vivo (chick chorioallantoic membrane (CAM), and Nude mice treatment assay).

RESULTS

Our results showed that the combination of two nanobodies (anti-VEGFR2/NRP-1 nanobodies) significantly inhibited proliferation as well as tube formation of human endothelial cells effective than a single nanobody. In addition, the mixture of both nanobodies inhibited vascularization of chick chorioallantoic membrane ex ovo CAM assay as compared to a single nanobody. Moreover, the mixture of both nanobodies significantly inhibited tumor growth of the mice (tumor volume and weight) higher than individual nanobodies (P < 0.05).

CONCLUSION

Our results offer a promising role of combination therapies in cancer therapy as well as angiogenesis.

Increased FOXM1 Expression by Cisplatin Inhibits Paclitaxel-Related Apoptosis in Cisplatin-Resistant Human Oral Squamous Cell Carcinoma (OSCC) Cell Lines

Cisplatin and paclitaxel are commonly used to treat oral cancer, but their use is often limited because of acquired drug resistance. Here, we tested the effects of combined cisplatin and paclitaxel on three parental (YD-8, YD-9, and YD-38) and three cisplatin-resistant (YD-8/CIS, YD-9/CIS, and YD-38/CIS) oral squamous cell carcinoma (OSCC) cell lines using cell proliferation assays and combination index analysis. We detected forkhead box protein M1 (FOXM1) mRNA and protein expression via real-time qPCR and Western blot assays. Cell death of the cisplatin-resistant cell lines in response to these drugs with or without a FOXM1 inhibitor (forkhead domain inhibitory compound 6) was then measured by propidium iodide staining and TdT dUTP nick end labeling (TUNEL) assays. In all six OSCC cell lines, cell growth was more inhibited by paclitaxel alone than combination therapy. Cisplatin-induced overexpression of FOXM1 showed the same trend only in cisplatin-resistant cell lines, indicating that it was associated with inhibition of paclitaxel-related apoptosis. In summary, these results suggest that, in three cisplatin-resistant cell lines, the combination of cisplatin and paclitaxel had an antagonistic effect, likely because cisplatin blocks paclitaxel-induced apoptosis. Cisplatin-induced FOXM1 overexpression may explain the failure of this combination.

Efficacy and safety of bevacizumab-based combination therapy for treatment of patients with metastatic colorectal cancer

Aim

The use of bevacizumab in combination therapy is an emerging trend in metastatic colorectal cancer treatment. However, the clinical value of different combination types remains under debate. Thus, a meta-analysis of randomized controlled trials (RCTs) comparing bevacizumab-based combination therapy with monotherapy (therapy that uses one type of treatment, such as chemotherapy or surgery alone, to treat metastatic colorectal cancer) was performed, aiming to evaluate the safety and efficacy of bevacizumab-based combination therapy and to find a more beneficial combination.

Methods

We searched for clinical studies that evaluated bevacizumab-based combination therapy in metastatic colorectal cancer. We extracted data from these studies to evaluate the relative risk (RR) of overall response rate (ORR) and grade 3/4 treatment-related adverse events (AEs), HRs of overall survival (OS), and progression-free survival (PFS).

Results

Eight RCTs were identified (n=3,424). Treatments included combinations of bevacizumab and oxaliplatin, fluorouracil, and leucovorin (FOLFOX4), combinations of bevacizumab and capecitabine and oxaliplatin, combinations of bevacizumab and fluorouracil/leucovorin, combinations of bevacizumab and irinotecan, fluorouracil, and leucovorin (IFL), and combinations of bevacizumab and capecitabine. Bevacizumab-based combination therapy showed higher ORR (RR: 1.40; 95% CI: 1.10-1.78; P=0.005), PFS (HR: 0.64; 95% CI: 0.55-0.73; P=0.000), and OS (HR: 0.82; 95% CI: 0.73-0.92; P=0.001) values than monotherapy. However, higher grade 3/4 treatment-related AEs (RR: 1.27; 95% CI: 1.15-1.41; P=0.000) were observed in combination therapy than in monotherapy.

Conclusion

This meta-analysis showed that the addition of IFL to bevacizumab better benefits PFS and safety. Adding FOLFOX4 was associated with better ORR and OS. The efficacy and safety of an IFL-bevacizumab-FOLFOX4 combination should be given greater weight in future clinical trials, guidelines, and clinical practice.

Tracking Tumor Colonization in Xenograft Mouse Models Using Accelerator Mass Spectrometry

Here we introduce an Accelerator Mass Spectrometry (AMS)-based high precision method for quantifying the number of cancer cells that initiate metastatic tumors, in xenograft mice. Quantification of ¹⁴C per cell prior to injection into animals, and quantification of ¹⁴C in whole organs allows us to extrapolate the number of cancer cells available to initiate metastatic tumors. The ¹⁴C labeling was optimized such that 1 cancer cell was detected among 1 million normal cells. We show that ~1–5% of human cancer cells injected into immunodeficient mice form subcutaneous tumors, and even fewer cells initiate metastatic tumors. Comparisons of metastatic site colonization between a highly metastatic (PC3) and a non-metastatic (LnCap) cell line showed that PC3 cells colonize target tissues in greater quantities at 2 weeks post-delivery, and by 12 weeks post-delivery no ¹⁴C was detected in LnCap xenografts, suggesting that all metastatic cells were cleared. The ¹⁴C-signal correlated with the presence and the severity of metastatic tumors. AMS measurements of ¹⁴C-labeled cells provides a highly-sensitive, quantitative assay to experimentally evaluate metastasis and colonization of target tissues in xenograft mouse models. This approach can potentially be used to evaluate tumor aggressiveness and assist in making informed decisions regarding treatment.

Tumor progression and metastatic dissemination in ovarian cancer after dose-dense or conventional paclitaxel and cisplatin plus bevacizumab

The efficacy of therapeutic regimens incorporating weekly or every-3-weeks paclitaxel (PTX) for ovarian cancer is debated. We investigated the addition of bevacizumab in regimens of chemotherapy with different PTX doses and schedules in preclinical models. Treatments were cisplatin (DDP) with weekly PTX (conventional), or dose-dense-equi (every other day to the conventional cumulative dose), or dose-dense-high (total dose 1.5 times higher), with or without bevacizumab. Treatment efficacy was evaluated analyzing tumor growth in different time-windows in two patient-derived ovarian cancer xenografts with different sensitivity to cisplatin. Tumor progression, metastasis and survival were studied in ovarian cancer models growing orthotopically and disseminating in the mouse peritoneal cavity. Short-term effects on cell cycle, tumor cell proliferation/apoptosis and vasculature were evaluated by flow cytometry and immunohistochemistry. PTX dose-dense (with/without DDP) was superior to the conventional scheme in a dose-dependent manner; the high efficacy was confirmed by the lower ratio of tumor to normal cells. All schemes benefited from bevacizumab, which reduced tumor vessels. However, DDP/PTX dose-dense-high (only chemotherapy) was at least as active as DDP/PTX conventional plus bevacizumab. DDP/PTX dose-dense-high plus bevacizumab was the most effective in delaying tumor progression, though it did not prolong mouse survival and the continuous treatment with bevacizumab was associated with a malignant disease. These findings indicate that the effect of bevacizumab in combination with chemotherapy may depend on the schedule-dose of the treatment and help to explain the unclear benefits after bevacizumab.

Lurbinectedin reduces tumour-associated macrophages and the inflammatory tumour microenvironment in preclinical models

Background:

Lurbinectedin is a novel anticancer agent currently undergoing late-stage (Phase II /III) clinical evaluation in platinum-resistant ovarian, BRCA1/2-mutated breast and small-cell lung cancer. Lurbinectedin is structurally related to trabectedin and it inhibits active transcription and the DNA repair machinery in tumour cells.

Methods:

In this study we investigated whether lurbinectedin has the ability to modulate the inflammatory microenvironment and the viability of myeloid cells in tumour-bearing mice.

Results:

Administration of lurbinectedin significantly and selectively decreased the number of circulating monocytes and, in tumour tissues, that of macrophages and vessels. Similar findings were observed when a lurbinectedin-resistant tumour variant was used, indicating a direct effect of lurbinectedin on the tumour microenviroment. In vitro, lurbinectedin induced caspase-8-dependent apoptosis of human purified monocytes, whereas at low doses it significantly inhibited the production of inflammatory/growth factors (CCL2, CXCL8 and VEGF) and dramatically impaired monocyte adhesion and migration ability. These findings were supported by the strong inhibition of genes of the Rho-GTPase family in lurbinectedin-treated monocytes.

Conclusions:

The results illustrate that lurbinectedin affects at multiple levels the inflammatory microenvironment by acting on the viability and functional activity of mononuclear phagocytes. These peculiar effects, combined with its intrinsic activity against cancer cells, make lurbinectedin a compound of particular interest in oncology.

Novel murine tumour models depend on strain and route of inoculation

This study describes variations in tumour growth patterns which occur when changes in the routes of inoculation and mouse strain are used to introduce tumours into established murine model systems that are known to vary in location and aggression. Intraperitoneal, subcutaneous, intravenous and hydrodynamic inoculations of B16F10 cells were compared among CD-1, C57BL/6 and Balb/c mice. Most surprisingly, allogeneic tumour growth in Balb/c mice after intravenous and hydrodynamic inoculation of B16F10 cells was faster than tumour growth in the syngeneic C57BL/6 mice. These and other variations in the tumour growth patterns described here can help provide the researcher with more experimental control when planning to use the optimal tumour model for any particular study.

Combination therapy in cancer: effects of angiogenesis inhibitors on drug pharmacokinetics and pharmacodynamics

Validated preclinical studies have provided evidence that anti-vascular endothelial growth factor (VEGF) compounds enhance the activity of subsequent antitumor therapy, but the mechanism of this potentiation is far from clear. The most widespread explanation is enhanced delivery of therapeutics due to vascular remodeling, lower interstitial pressure, and increased blood flow. While the antiangiogenic effects on vascular morphology have been fairly consistent in both preclinical and clinical settings, the improvement of tumor vessel function is debated. This review focuses on the effect of anti-VEGF therapy on tumor microenvironment morphology and functions, and its therapeutic benefits when combined with other therapies. The uptake and spatial distribution of chemotherapeutic agents into the tumor after anti-VEGF are examined.

Orthotopic Model of Ovarian Cancer

Epithelial ovarian cancer (EOC) is the fifth commonest cancer-related cause of female death in the developed world. In spite of current surgical and chemotherapeutic options the vast majority of patients have widely metastatic disease and the survival rate has not much changed over the last years. The anti-angiogenic drugs are driving the field of agents targeting the tumor microenvironment in ovarian cancer. Preclinical models that accurately reproduce the molecular and biological features of ovarian cancer patients are a valuable means of producing reliable data on personalized medicine and predicting the therapeutic response in clinical trials.In this methodological chapter we describe the orthotopic model of ovarian cancer implanted under the ovarian bursa of mice. In spite of anatomical differences between the rodent and human bursa-fallopian tube, the appropriate primary tumor microenvironment at the site of the implant allows investigation of tumor-stroma interactions (e.g., angiogenesis), and is well suited for studying the tumor dissemination and metastasis typical of this disease.This model-although fairly labor intensive-may be useful for assessing novel, more selective therapeutic interventions and for biomarker discovery, reflecting the behavior of this disease.

Pharmacokinetic strategies to improve drug penetration and entrapment within solid tumors

Despite the discovery of a large number of anticancer agents, cancer still remains among the leading causes of death since the middle of the twentieth century. Solid tumors possess a high degree of genetic instability and emergence of treatment resistance. Tumor resistance has emerged for almost all approved anticancer drugs and will most probably emerge for newly discovered anticancer agents as well. The use of pharmacokinetic approaches to increase anticancer drug concentrations within the solid tumor compartment and prolong its entrapment might diminish the possibility of resistance emergence at the molecular pharmacodynamic level and might even reverse tumor resistance. Several novel treatment modalities such as metronomic therapy, angiogenesis inhibitors, vascular disrupting agents and tumor priming have been introduced to improve solid tumor treatment outcomes. In the current review we will discuss the pharmacokinetic aspect of these treatment modalities in addition to other older treatment modalities, such as extracellular matrix dissolving agents, extracellular matrix synthesis inhibitors, chemoembolization and cellular efflux pump inhibition. Many of these strategies showed variable degrees of success/failure; however, reallocating these modalities based on their influence on the intratumoral pharmacokinetics might improve their understanding and treatment outcomes.

Bevacizumab: a review of its use in advanced cancer

The humanized monoclonal antibody bevacizumab (Avastin(®)) has been available in the EU since 2005. Results of phase III trials demonstrate that adding intravenous bevacizumab to antineoplastic agents improves progression-free survival and/or overall survival in patients with advanced cancer, including when used as first- or second-line therapy in metastatic colorectal cancer, as first-line therapy in advanced nonsquamous non-small cell lung cancer, as first-line therapy in metastatic renal cell carcinoma, as first-line therapy in metastatic breast cancer, and as first-line therapy in epithelial ovarian, fallopian tube or primary peritoneal cancer or in recurrent, platinum-sensitive or platinum-resistant disease. Results of these studies are supported by the findings of routine oncology practice studies conducted in real-world settings. The tolerability profile of bevacizumab is well defined and adverse events associated with its use (e.g. hypertension, proteinuria, haemorrhage, wound healing complications, arterial thromboembolism, gastrointestinal perforation) are generally manageable. In conclusion, bevacizumab remains an important option for use in patients with advanced cancer.

Cediranib combined with chemotherapy reduces tumor dissemination and prolongs the survival of mice bearing patient-derived ovarian cancer xenografts with different responsiveness to cisplatin

Cediranib is a pan-vascular endothelial growth factor receptor tyrosine kinase inhibitor that affects tumor angiogenesis and is under investigation in clinical studies on ovarian cancer. Using a panel of eleven patient-derived ovarian cancer xenografts (EOC-PDX) growing orthotopically in the peritoneal cavity of nude mice we investigated the effect of cediranib as monotherapy or in combination with chemotherapy on overall survival (primary endpoint, at euthanasia), and tumor dissemination and metastasis in the peritoneal cavity (secondary endpoint, interim analysis). The response of EOC-PDX to cediranib varied (increment of lifespan, ILS between 12 and 85 %) in the different EOC-PDX, independently from tumor responsiveness to cisplatin (DDP). Cediranib combined with DDP and in maintenance regimen prolonged the survival of mice bearing EOC-PDX with different responsiveness to DDP (ILS between 34 and 224 % with only DDP and between 135 and 337 % with DDP plus Cediranib); survival was extended with the addition of paclitaxel to chemotherapy (50-77 % complete remissions). Cediranib reduced ascites of advanced EOC-PDX, but had limited effect on tumor dissemination; only combined with chemotherapy, ascites and metastases were both reduced. The reduction of tumor dissemination was associated to the increase of overall survival. In conclusion, the response to cediranib differs in the various EOC-PDX, reproducing the heterogeneous response of cancer patients to angiogenesis inhibitors. Cediranib potentiated chemotherapy, significantly inhibiting tumor progression and dissemination to metastatic organs, even in tumors poorly responsive to DDP. EOC-PDX preclinical models with different responsiveness to Cediranib may help in identifying determinants of response to cediranib and mechanisms of adaptation to antiangiogenic treatments.

Preclinical optimization of a broad-spectrum anti-bladder cancer tri-drug regimen via the Feedback System Control (FSC) platform

Therapeutic outcomes of combination chemotherapy have not significantly advanced during the past decades. This has been attributed to the formidable challenges of optimizing drug combinations. Testing a matrix of all possible combinations of doses and agents in a single cell line is unfeasible due to the virtually infinite number of possibilities. We utilized the Feedback System Control (FSC) platform, a phenotype oriented approach to test 100 options among 15,625 possible combinations in four rounds of assaying to identify an optimal tri-drug combination in eight distinct chemoresistant bladder cancer cell lines. This combination killed between 82.86% and 99.52% of BCa cells, but only 47.47% of the immortalized benign bladder epithelial cells. Preclinical in vivo verification revealed its markedly enhanced anti-tumor efficacy as compared to its bi- or mono-drug components in cell line-derived tumor xenografts. The collective response of these pathways to component drugs was both cell type- and drug type specific. However, the entire spectrum of pathways triggered by the tri-drug regimen was similar in all four cancer cell lines, explaining its broad spectrum killing of BCa lines, which did not occur with its component drugs. Our findings here suggest that the FSC platform holdspromise for optimization of anti-cancer combination chemotherapy.

PG545 enhances anti-cancer activity of chemotherapy in ovarian models and increases surrogate biomarkers such as VEGF in preclinical and clinical plasma samples

BACKGROUND

Despite the utility of antiangiogenic drugs in ovarian cancer, efficacy remains limited due to resistance linked to alternate angiogenic pathways and metastasis. Therefore, we investigated PG545, an anti-angiogenic and anti-metastatic agent which is currently in Phase I clinical trials, using preclinical models of ovarian cancer.

METHODS

PG545's anti-cancer activity was investigated in vitro and in vivo as a single agent, and in combination with paclitaxel, cisplatin or carboplatin using various ovarian cancer cell lines and tumour models.

RESULTS

PG545, alone, or in combination with chemotherapeutics, inhibited proliferation of ovarian cancer cells, demonstrating synergy with paclitaxel in A2780 cells. PG545 inhibited growth factor-mediated cell migration and reduced HB-EGF-induced phosphorylation of ERK, AKT and EGFR in vitro and significantly reduced tumour burden which was enhanced when combined with paclitaxel in an A2780 model or carboplatin in a SKOV-3 model. Moreover, in the immunocompetent ID8 model, PG545 also significantly reduced ascites in vivo. In the A2780 maintenance model, PG545 initiated with, and following paclitaxel and cisplatin treatment, significantly improved overall survival. PG545 increased plasma VEGF levels (and other targets) in preclinical models and in a small cohort of advanced cancer patients which might represent a potential biomarker of response.

CONCLUSION

Our results support clinical testing of PG545, particularly in combination with paclitaxel, as a novel therapeutic strategy for ovarian cancer.

Patient-derived ovarian tumor xenografts recapitulate human clinicopathology and genetic alterations

Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy. On the basis of its histopathology and molecular-genomic changes, ovarian cancer has been divided into subtypes, each with distinct biology and outcome. The aim of this study was to develop a panel of patient-derived EOC xenografts that recapitulate the molecular and biologic heterogeneity of human ovarian cancer. Thirty-four EOC xenografts were successfully established, either subcutaneously or intraperitoneally, in nude mice. The xenografts were histologically similar to the corresponding patient tumor and comprised all the major ovarian cancer subtypes. After orthotopic transplantation in the bursa of the mouse ovary, they disseminate into the organs of the peritoneal cavity and produce ascites, typical of ovarian cancer. Gene expression analysis and mutation status indicated a high degree of similarity with the original patient and discriminate different subsets of xenografts. They were very responsive, responsive, and resistant to cisplatin, resembling the clinical situation in ovarian cancer. This panel of patient-derived EOC xenografts that recapitulate the recently type I and type II classification serves to study the biology of ovarian cancer, identify tumor-specific molecular markers, and develop novel treatment modalities.

First in-mouse development and application of a surgically relevant xenograft model of ovarian carcinoma

Purpose

Preclinical models of epithelial ovarian cancer have not been exploited to evaluate the clinical standard combination therapy of surgical debulking with follow-up chemotherapy. As surgery is critical to patient survival, here we establish a combined surgical/chemotherapy xenograft model of epithelial ovarian cancer and demonstrate its translational relevance.

Experimental Design

SKOV-3^luc+ ovary cancer cells were injected topically into the ovaries of immunodeficient mice. Disease development and effect of clinical standard treatment including hysterectomy, bilateral salpingoophorectomy and removal of metastasis with follow up chemotherapy (carboplatin 12 mg/kg + paclitaxel 15 mg/kg) was evaluated by clinical parameters. Tumor burden was quantified by bioluminescence imaging (BLI).

Results

The xenograft ovarian tumors developed were poorly differentiated and multicystic and the disease disseminated into the peritoneal cavity. When compared to the controls with a mean survival time of 4.9 weeks, mice treated with surgery and chemotherapy, surgery or chemotherapy demonstrated significantly improved mean survival of 16.1 weeks (p = 0.0008), 12.7 weeks (p = 0.0008), or 10.4 weeks (p = 0.008), respectively.

Conclusion

Combined surgical intervention and adjuvant chemotherapy was demonstrated for the first time in an orthotopic xenograft model of ovarian cancer. Similar to observation in human studies the combined approach resulted in the longest medial survival time, advocating application of this strategy in future preclinical therapeutic development for this disease.

Vascular endothelial growth factor c promotes ovarian carcinoma progression through paracrine and autocrine mechanisms

Vascular endothelial growth factor C (VEGFC) has been reported to promote tumor progression in several tumor types, mainly through the stimulation of lymphangiogenesis and lymphatic metastasis. However, the expression and biological significance of the VEGFC/VEGF receptor (VEGFR)-3 pathway in ovarian cancer growth and dissemination are unclear, and have been investigated in this study. Soluble VEGFC was detected in the plasma and ascites of patients with ovarian carcinoma, and VEGFR3 expression was found in their tumor tissues. In human ovarian carcinoma xenograft models, high levels of soluble VEGFC in ascites and serum were detected, in association with disease progression, tumor burden, and volume of ascites. Peak VEGFC expression preceded para-aortic lymph node infiltration by HOC8 neoplastic cells. Histological detection of tumor cells in blood and lymphatic vessels indicated both hematogenous and lymphatic dissemination. Overexpression of VEGFC in the VEGFR3-positive and luciferase-expressing IGROV1 cells promoted carcinoma dissemination after orthotopic transplantation in the ovary of immunodeficient mice. In vitro, VEGFC released by the tumor cells stimulated tumor cell migration in an autocrine manner. Cediranib, an inhibitor of VEGFR1-3 and c-kit, inhibited in vivo metastasis of VEGFC-overexpressing IGROV1 and in vitro autocrine effects. These findings suggest that the VEGFC/VEGFR3 pathway acts as an enhancer of ovarian cancer progression through autocrine and paracrine mechanisms, hence offering a potential target for therapy.

Tumor delivery of chemotherapy combined with inhibitors of angiogenesis and vascular targeting agents

Numerous angiogenesis-vascular targeting agents have been admitted to the ranks of cancer therapeutics; most are used in polytherapy regimens. This review looks at recent progress and our own preclinical experience in combining angiogenesis inhibitors, mainly acting on VEGF/VEGFR pathways, and vascular targeting agents with conventional chemotherapy, discussing the factors that determine the outcome of these treatments. Molecular and morphological modifications of the tumor microenvironment associated with drug distribution and activity are reviewed. Modalities to improve drug delivery and strategies for optimizing combination therapy are examined.