Bevacizumab and ovarian cancer

Deep Learning Can Predict Bevacizumab Therapeutic Effect and Microsatellite Instability Directly from Histology in Epithelial Ovarian Cancer

Epithelial ovarian cancer (EOC) remains a significant cause of mortality among gynecologic cancers, with the majority of cases being diagnosed at an advanced stage. Before targeted therapies were available, EOC treatment relied largely on debulking surgery and platinum-based chemotherapy. Vascular endothelial growth factors have been identified as inducing tumor angiogenesis. According to several clinical trials, anti-vascular endothelial growth factor-targeted therapy with bevacizumab was effective in all phases of EOC treatment. However, there are currently no biomarkers accessible for regular therapeutic use despite the importance of patient selection. Microsatellite instability (MSI), caused by a deficiency of the DNA mismatch repair system, is a molecular abnormality observed in EOC associated with Lynch syndrome. Recent evidence suggests that angiogenesis and MSI are interconnected. Developing predictive biomarkers, which enable the selection of patients who might benefit from bevacizumab-targeted therapy or immunotherapy, is critical for realizing personalized precision medicine. In this study, we developed 2 improved deep learning methods that eliminate the need for laborious detailed image-wise annotations by pathologists and compared them with 3 state-of-the-art methods to not only predict the efficacy of bevacizumab in patients with EOC using mismatch repair protein immunostained tissue microarrays but also predict MSI status directly from histopathologic images. In prediction of therapeutic outcomes, the 2 proposed methods achieved excellent performance by obtaining the highest mean sensitivity and specificity score using MSH2 or MSH6 markers and outperformed 3 state-of-the-art deep learning methods. Moreover, both statistical analysis results, using Cox proportional hazards model analysis and Kaplan-Meier progression-free survival analysis, confirm that the 2 proposed methods successfully differentiate patients with positive therapeutic effects and lower cancer recurrence rates from patients experiencing disease progression after treatment (P < .01). In prediction of MSI status directly from histopathology images, our proposed method also achieved a decent performance in terms of mean sensitivity and specificity score even for imbalanced data sets for both internal validation using tissue microarrays from the local hospital and external validation using whole section slides from The Cancer Genome Atlas archive.

Gentian Violet Inhibits Cell Proliferation through Induction of Apoptosis in Ovarian Cancer Cells

Gentian violet (GV) is known to have antibacterial and antifungal effects, but recent studies have demonstrated its inhibitory effects on the growth of several types of cancer cells. Here, we investigated the anticancer efficacy of GV in ovarian cancer cells. GV significantly reduced the proliferation of OVCAR8, SKOV3, and A2780 cells. Results of transferase dUTP nick and labeling (TUNEL) assay and Western blot assay indicated that the inhibitory effect of GV on ovarian cancer cells was due to the induction of apoptosis. Moreover, GV significantly increased reactive oxygen species (ROS) and upregulated the expression of p53, PUMA, BAX, and p21, critical components for apoptosis induction, in ovarian cancer cells. Our results suggest that GV is a novel antiproliferative agent and is worthy of exploration as a potential therapeutic agent for ovarian cancer.

Angiogenesis: A Pivotal Therapeutic Target in the Drug Development of Gynecologic Cancers

Simple Summary

Angiogenesis, defined as the abnormal development of new blood vessels in cancer, is a key component of cancer development. Clinical trials have proven that angiogenesis blockers can be effective in halting cancer growth across numerous types of gynecologic cancers. This review discusses the mechanisms of angiogenesis in gynecologic cancers, current practices and areas for development.

Abstract

Since the discovery of angiogenesis and its relevance to the tumorigenesis of gynecologic malignancies, a number of therapeutic agents have been developed over the last decade, some of which have become standard treatments in combination with other therapies. Limited clinical activity has been demonstrated with anti-angiogenic monotherapies, and ongoing trials are focused on combination strategies with cytotoxic agents, immunotherapies and other targeted treatments. This article reviews the science behind angiogenesis within the context of gynecologic cancers, the evidence supporting the targeting of these pathways and future directions in clinical trials.

Mutated TP53 is a marker of increased VEGF expression: analysis of 7,525 pan-cancer tissues

Anti-angiogenic therapies are an important class of anti-cancer treatment drugs. However, their efficacy is limited to certain tumors and would benefit from identifying a biomarker predictive of therapeutic response. TP53 (tumor protein p53) is a tumor suppressor gene frequently mutated in cancer and implicated in cell-cycle regulation, apoptosis, and angiogenesis. Data from 7,525 unique tumor samples (representing 30 tumor cohorts) were retrieved from the TCGA database to analyze the relationship between TP53-mutation status and VEGFA (vascular endothelial growth factor A) expression. Univariate analyses were done using a Mann-Whitney univariate test or Fisher's exact test. Parameters with a p-value (p)≤0.1 in univariate analysis were selected for follow-up multivariate analyses, including TP53-mutation status, cancer cohorts, cancer subtypes, and VEGFA expression. Our analysis demonstrates statistically significant increases in VEGFA mRNA tissue expression in TP53-mutated adenocarcinomas (but not in squamous cancers) compared to TP53 wild-type tumors. This association holds true in multivariate analyses and remains independent of HIF-1α and MDM2 overexpression. Our findings provide additional evidence that TP53 mutations are linked to the VEGF pathway, potentially offering insight into the mechanism behind increased sensitivity to anti-angiogenic therapies observed in some TP53-mutant tumors.

RGS5 decreases the proliferation of human ovarian carcinoma‑derived primary endothelial cells through the MAPK/ERK signaling pathway in hypoxia

Regulator of G-protein signaling 5 (RGS5), a tissue-specific signal-regulating molecule, plays a key role in the development of the vasculature. It was recently found that RGS5 is abundantly expressed in epithelial ovarian cancer (EOC) compared with the normal ovaries. However, the distribution of RGS5 in EOC and its significance require further investigation. The aim of the present study was to investigate the expression of RGS5 in EOC, as well as its association with cancer differentiation, metastasis and clinicopathological parameters. Immunohistochemistry (IHC), western blotting, RT-PCR, wound-healing, cell proliferation and flow cytometric assays were the methods used in the present study. RGS5 was highly expressed in the cytoplasm of ovarian carcinoma cells and in microvascular structures. The expression of RGS5 in EOC was negatively associated with peritoneal metastasis (P=0.004), but it was not found to be associated with age, tumor size, clinical stage or lymph node metastasis (P>0.05). EOC patients with high RGS5 expression had a prolonged progression-free survival (72.34±8.41 vs. 43.56±5.41 months, P<0.001). High expression of RGS5 was correlated with significantly lower microvascular density (MVD) as indicated by the expression of CD34, whereas the opposite was observed in tissues with low RGS5 expression (P<0.05). Hypoxia increased RGS5 expression in ovarian carcinoma-derived endothelial cells (ODMECs), whereas the proliferative capacity of ODMECs exhibited a significant increase following RNAi-mediated reduction of RGS5 expression. These data indicated that RGS5 plays a key role in angiogenesis in ovarian carcinoma. In addition, RGS5 downregulated the expression of the downstream proteins CDC25A, CDK2 and cyclin E, which are mediated by the mitogen-activated protein kinase/extracellular signal-regulated kinase pathway, causing ODMEC arrest in the G1 phase of the cell cycle under hypoxic conditions. Collectively, our data indicated that RGS5 is crucial for the occurrence and development of ovarian cancer, and that RGS5 and its signaling pathway may serve as anti-angiogenesis targets for the treatment of ovarian cancer.

A new promising way of maintenance therapy in advanced ovarian cancer: a comparative clinical study

Background

There is an urgent need for more novel and efficacious therapeutic agents and strategies for the treatment of ovarian cancer - one of the most formidable female malignancies. These approaches should be based on comprehensive understanding of the pathobiology of this cancer and focused on decreasing its recurrence and metastasis. The aim of this study was to evaluate the efficacy of five-year maintenance therapy with indole-3-carbinol (I3C) as well as I3C and epigallocatechin-3-gallate (EGCG) conducted before, during, and after combined treatment compared with combined treatment alone in advanced ovarian cancer.

Methods

Patients with stage III-IV serous ovarian cancer were assigned to receive combined treatment plus I3C (arm 1), combined treatment plus I3C and EGCG (arm 2), combined treatment plus I3C and EGCG plus long-term platinum-taxane chemotherapy (arm 3), combined treatment alone without neoadjuvant platinum-taxane chemotherapy (control arm 4), and combined treatment alone (control arm 5). Combined treatment included neoadjuvant platinum-taxane chemotherapy, surgery, and adjuvant platinum-taxane chemotherapy. The primary endpoint was overall survival (OS). Secondary endpoints were progression-free survival (PFS) and rate of patients with recurrent ovarian cancer with ascites after combined treatment.

Results

After five years of follow-up, maintenance therapy dramatically prolonged PFS and OS compared to control. Median OS was 60.0 months (95% CI: 58.0–60.0 months) in arm 1, 60.0 months (95% CI: 60.0–60.0 months) in arms 2 and 3 while 46.0 months (95% СI: 28.0–60.0 months) in arm 4, and 44.0 months (95% СI: 33.0–58.0 months) in arm 5. Median PFS was 39.5 months (95% СI: 28.0–49.0 months) in arm 1, 42.5 months (95% СI: 38.0–49.0 months) in arm 2, 48.5 months (95% СI: 39.0–53.0 months) in arm 3, 24.5 months (95% СI: 14.0–34.0 months) in arm 4, 22.0 months (95% СI: 15.0–26.0 months) in arm 5. The rate of patients with recurrent ovarian cancer with ascites after combined treatment was significantly less in maintenance therapy arms compared to control.

Conclusions

Long-term usage of I3C and EGCG may represent a new promising way of maintenance therapy in advanced ovarian cancer patients, which achieved better treatment outcomes.

Trial registration

Retrospectively registered with ANZCTR number: ACTRN12616000394448. Date of registration: 24/03/2016.

Recurrent colon perforation after discontinuation of bevacizumab for ovarian cancer

Bevacizumab (Bev) is an antiangiogenic drug used to treat various malignances, including ovarian cancer (OC). Bev is generally well-tolerated; however, it has a characteristic toxicity profile. In particular, gastrointestinal perforation (GIP) is a rare but serious side effect that can be lethal. A 55-year-old woman with recurrent OC had an episode of GIP during third-line chemotherapy comprising Bev and topotecan (TPT). Bev was discontinued while TPT was continued as monotherapy. Three months after discontinuation of Bev, the patient presented with left lower abdominal pain and was diagnosed with a second GIP. She had emergent surgery. One year later, she is still alive and healthy, and is continuing TPT. This is the first report of recurrent GIP after discontinuation of Bev. Our case suggests that physicians should be aware of GIP even after the discontinuation of Bev.

Folic acid-targeted iron oxide nanoparticles as contrast agents for magnetic resonance imaging of human ovarian cancer

BACKGROUND

Improved methods for the early and specific detection of ovarian cancer are needed.

METHODS

In this experimental study, we used folic acid (FA)-targeted iron oxide (Fe3O4) nanoparticles (NPs) as a T2-negative contrast agent for magnetic resonance (MR) imaging to accurately detect ovarian cancer tissues in an intraperitoneal xenograft tumor model. Human serous ovarian cell line (Skov-3), with overexpressed FA receptors, was chosen as the targeted tumor cell mode. For in vivo experiments, the cells were injected intraperitoneally into nude mice to produce intraabdominal ovarian cancers. FA-targeted and non-targeted Fe3O4 NPs were prepared.

RESULTS

FA-targeted Fe3O4 NPs with a mean size of 9.2 ± 1.7 nm have a negligible cytotoxicity to human serous ovarian cell line (Skov-3). Importantly, the results of cellular uptake suggested that FA-targeted Fe3O4 NPs have a targeting specificity to Skov-3 cells overexpressing FA receptors. FA-targeted Fe3O4 NPs could be specifically localized by magnetic resonance (MR) imaging to the intraperitoneal human ovarian carcinoma tissues, as documented by a statistically significant difference (p = 0.002, n = 3) in T2 signal intensities of xenograft tumor tissues when injected with FA-targeted and non-targeted Fe3O4 NPs at 4 h post-injection.

CONCLUSION

FA-targeted Fe3O4 NPs appear to be promising agents for the detection of human ovarian carcinoma by MR imaging, and possibly also for the hyperthermal treatment of the tumors.

DIRAS3 regulates the autophagosome initiation complex in dormant ovarian cancer cells

DIRAS3 is an imprinted tumor suppressor gene that is downregulated in 60% of human ovarian cancers. Re-expression of DIRAS3 at physiological levels inhibits proliferation, decreases motility, induces autophagy, and regulates tumor dormancy. Functional inhibition of autophagy with choroquine in dormant xenografts that express DIRAS3 significantly delays tumor regrowth after DIRAS3 levels are reduced, suggesting that autophagy sustains dormant ovarian cancer cells. This study documents a newly discovered role for DIRAS3 in forming the autophagosome initiation complex (AIC) that contains BECN1, PIK3C3, PIK3R4, ATG14, and DIRAS3. Participation of BECN1 in the AIC is inhibited by binding of BECN1 homodimers to BCL2. DIRAS3 binds BECN1, disrupting BECN1 homodimers and displacing BCL2. Binding of DIRAS3 to BECN1 increases the association of BECN1 with PIK3C3 and ATG14, facilitating AIC activation. Amino acid starvation of cells induces DIRAS3 expression, reduces BECN1-BCL2 interaction and promotes autophagy, whereas DIRAS3 depletion blocks amino acid starvation-induced autophagy. In primary ovarian cancers, punctate expression of DIRAS3, BECN1, and the autophagic biomarker MAP1LC3 are highly correlated (P<0.0001), underlining the clinical relevance of these mechanistic studies. Punctate expression of DIRAS3 and MAP1LC3 was detected in only 21-23% of primary ovarian cancers but in 81-84% of tumor nodules found on the peritoneal surface at second-look operations following primary chemotherapy. This reflects a 4-fold increase (P<0.0001) in autophagy between primary disease and post-treatment recurrence. We suggest that DIRAS3 not only regulates the AIC, but induces autophagy in dormant, nutrient-deprived ovarian cancer cells that remain after conventional chemotherapy, facilitating their survival.

Comparison of montelukast and cabergoline for prevention of ovarian hyperstimulation syndrome: in an experimental rat model

Ovarian hyperstimulation syndrome (OHSS) is a serious iatrogenic complication that can occur during assisted reproductive techniques. The aim of this study is to investigate the effects of the leukotriene receptor antagonist (montelukast) treatment in prevention of OHSS and compare to cabergoline treatment. Twenty-four immature female Wistar rats were assigned to four groups. Group 1 was the control group. In the remaining three groups, OHSS was induced through ovarian stimulation with gonadotropins. No treatment was given to Group 2. Group 3 was administered a low-dose 100 mg/kg cabergoline treatment and Group 4 was received 20 mg/kg montelukast. Body weight, ovarian weight, vasculary permability (VP), peritoneal fluid vascular endothelial growth factor (VEGF) values and VEGF immune-expression were compared between the groups. Both cabergoline and montelukast prevented progression of OHSS compared to the OHSS group. Body weight, ovarian weight, VP, peritoneal fluid VEGF values and VEGF expression were significantly lower in both cabergoline- and montelukast-treated rats than in those not treated OHSS group. In conclusion, montelukast is an effective option for prevention of OHSS, as well as cabergoline. Montelukast may be a new treatment option to prevent and control the OHSS.

VEGF-A Expression Correlates with TP53 Mutations in Non-Small Cell Lung Cancer: Implications for Antiangiogenesis Therapy

Bevacizumab is one of the most widely used antiangiogenic drugs in oncology, but the overall beneficial effects of this VEGF-A targeting agent are relatively modest, in part due to the lack of a biomarker to select patients most likely to respond favorably. Several molecular aberrations in cancer influence angiogenesis, including mutations in the tumor suppressor gene TP53, which occur frequently in many human malignancies. In this study, we present a multiple regression analysis of transcriptomic data in 123 patients with non-small cell lung cancer (NSCLC) showing that TP53 mutations are associated with higher VEGF-A expression (P = 0.006). This association was interesting given a recent retrospective study showing longer progression-free survival in patients with diverse tumors who receive bevacizumab, if tumors harbor mutant TP53 instead of wild-type TP53. Thus, our current findings linking TP53 mutation with VEGF-A upregulation offered a mechanistic explanation for why patients exhibit improved outcomes after bevacizumab treatment when their tumors harbor mutant TP53 versus wild-type TP53. Overall, this work warrants further evaluation of TP53 as a ready biomarker to predict bevacizumab response in NSCLC and possibly other tumor types.

Thrombocytosis as a prognostic marker in stage III and IV serous ovarian cancer

Objective

Thrombocytosis is an adverse prognostic factor in many types of cancer. We investigated if pre-treatment increased platelet counts provide prognostic information specifically in patients with stage III and IV serous ovarian cancer which is the most common clinical presentation of ovarian cancer.

Methods

Platelet number on diagnosis of stage III and IV serous ovarian adenocarcinoma was evaluated in 91 patients for whom there were complete follow-up data on progression and survival. Survival and progression free survival of patients with normal platelet counts (150-350 ×10⁹/L) was compared with that of patients with thrombocytosis (>350×10⁹/L) by χ² and logrank tests.

Results

The median age of the patients was 66 years-old. From the 91 patients, 52 (57.1%) had normal platelet counts (median, 273×10⁹/L; range, 153-350) at diagnosis of their disease and 39 patients (42.9%) had thrombocytosis (median, 463×10⁹/L; range, 354-631). In the group of patients with normal platelet counts, 24 of the 52 patients had died with a median survival of 43 months (range, 3-100). In the group of patients with thrombocytosis, 24 of the 39 patients had died with a median survival of 23 months (range, 4-79). In the entire group of 91 patients there was a statistically significant difference of the overall survival and progression-free survival between the two groups (logrank test P=0.02 and P=0.007, respectively).

Conclusion

In this retrospective analysis of stage III and IV ovarian cancer patients, thrombocytosis at the time of diagnosis had prognostic value regarding overall survival and progression-free survival.

Neoadjuvant chemotherapy in advanced ovarian cancer: latest results and place in therapy

Approximately 70% of women with epithelial ovarian cancer (EOC) are diagnosed with advanced stage disease, which is associated with high morbidity and mortality. The standard approach to treating patients with advanced EOC remains primary debulking surgery (PDS) followed by chemotherapy. EOC is one of the most sensitive of all solid tumors to cytotoxic drugs, with over 80% of women showing a response to standard chemotherapy combined with taxane and platinum. Furthermore, residual disease is a major prognostic factor for survival. On the basis of the clinical features, neoadjuvant chemotherapy (NACT) followed by interval debulking surgery (IDS) is considered to be an alternative treatment option to standard treatment in patients unable to undergo complete resection during PDS. Noninferiority of NACT-IDS to PDS has been demonstrated in some randomized controlled trials and meta-analyses. NACT would also lead to improved quality of life (QOL) of patients, however there are still problems to be solved in the treatment strategy. The uncertainty of perioperative visual assessment of tumor dissemination after NACT has been reported. In addition, several papers have shown the possibility that NACT induces platinum resistance. Furthermore, a notable risk associated with NACT is that patients with significant side effects and refractory disease will lose the opportunity for debulking surgery. Appropriate selection of the patient cohort for NACT is an important issue. Bevacizumab (Bev) is active in patients with advanced EOC. However, the use of Bev is not recommended in the neoadjuvant setting. Bev has a specific adverse event profile that needs to be considered, especially for surgical management, such as gastrointestinal perforation, hemorrhage, and thromboembolic events. NACT could be an alternative treatment option in patients with stage III or IV EOC. However, further studies are needed to clarify the precise role of NACT in the management of advanced EOC.

Zirconium-89 labeled antibodies: a new tool for molecular imaging in cancer patients

Antibody based positron emission tomography (immuno-PET) imaging is of increasing importance to visualize and characterize tumor lesions. Additionally, it can be used to identify patients who may benefit from a particular therapy and monitor the therapy outcome. In recent years the field is focused on ⁸⁹Zr, a radiometal with near ideal physical and chemical properties for immuno-PET. In this review we will discuss the production of  ⁸⁹Zr, the bioconjugation strategies, and applications in (pre-)clinical studies of  ⁸⁹Zr-based immuno-PET in oncology. To date, ⁸⁹Zr-based PET imaging has been investigated in a wide variety of cancer-related targets. Moreover, clinical studies have shown the feasibility for ⁸⁹Zr-based immuno-PET to predict and monitor treatment, which could be used to tailor treatment for the individual patient. Further research should be directed towards the development of standardized and robust conjugation methods and improved chelators to minimize the amount of released Zr⁴⁺ from the antibodies. Additionally, further validation of the imaging method is required. The ongoing development of new ⁸⁹Zr-labeled antibodies directed against novel tumor targets is expected to expand applications of  ⁸⁹Zr-labeled immuno-PET to a valuable method in the medical imaging.

Comparison of bevacizumab and cabergoline in the treatment of ovarian hyperstimulation syndrome in a rat model

The aim of this study is to investigate the effects of bevacizumab in a rat model of ovarian hyperstimulation syndrome (OHSS) and compare with cabergoline. The study was performed with 24 rats in four main groups (one non-stimulated control and three OHSS treatment groups; bevacizumab, cabergoline and placebo). The rats were randomly assigned to four experimental groups (six rats per group). Efficacy of treatment was assessed on 29th day by measuring weight gain, number of eggs, presence of ascites and ovarian weight. Peritoneal fluid levels of vascular endothelial growth factor (VEGF) were measured using an enzyme-linked immunosorbent assay. Ovarian weights were significantly higher in the OHSS groups than the control group. Ovarian weights in OHSS placebo group were found to be higher than those in OHSS-treatment groups (p = 0.002). VEGF levels were found increased in the OHSS-placebo group compared with the control group (p < 0.05). This increase was not seen in the OHSS groups treated with either bevacizumab or cabergoline. We demonstrate in this study that bevacizumab can lower VEGF production and ovarian weight in rats treated with gonadotropins.

Angiogenesis-related pathways in the pathogenesis of ovarian cancer

Ovarian Cancer represents the most fatal type of gynecological malignancies. A number of processes are involved in the pathogenesis of ovarian cancer, especially within the tumor microenvironment. Angiogenesis represents a hallmark phenomenon in cancer, and it is responsible for tumor spread and metastasis in ovarian cancer, among other tumor types, as it leads to new blood vessel formation. In recent years angiogenesis has been given considerable attention in order to identify targets for developing effective anti-tumor therapies. Growth factors have been identified to play key roles in driving angiogenesis and, thus, the formation of new blood vessels that assist in "feeding" cancer. Such molecules include the vascular endothelial growth factor (VEGF), the platelet derived growth factor (PDGF), the fibroblast growth factor (FGF), and the angiopoietin/Tie2 receptor complex. These proteins are key players in complex molecular pathways within the tumor cell and they have been in the spotlight of the development of anti-angiogenic molecules that may act as stand-alone therapeutics, or in concert with standard treatment regimes such as chemotherapy. The pathways involved in angiogenesis and molecules that have been developed in order to combat angiogenesis are described in this paper.

Vascular-disrupting agents in oncology

INTRODUCTION

Vascular-disrupting agents (VDAs) are a new class of oncology drugs, which specifically target established tumor neovasculature and have a relatively low toxicity profile. VDAs generally have non-overlapping side effects when concomitantly used with conventional cytotoxics. Several members of the VDA class have recently progressed through mid-to-late stages of clinical trials.

AREAS COVERED

We examined recent publications on preclinical findings and Phase I/II/III clinical trial data on mechanisms of actions, toxicities, and optimal use of VDA class drugs. It is becoming apparent that VDAs should be used in combination with other classes of cytotoxic agents for the optimization of their effect in treating various cancers. In this article we describe doses, timing of delivery, and sequence of combined therapy. We also address the combined mechanisms of actions of VDAs and conventional cytotoxic medications.

EXPERT OPINION

Vascular-disrupting agents represent a new class of promising anticancer agents, which exhibit synergistic and/or additive effects in combination with many conventional cytotoxics. Pharmacological evaluation of the optimal combinations of VDAs with agents of other classes and drug interactions need to be continued. Further clinical and preclinical studies are required for distinguishing cancer patients' subpopulations that would most benefit from VDAs, identifying tumor biomarkers predictive of response as well as reliable and reproducible imaging and/or biological assays indicative of pharmacodynamic effects, and establishing clinical algorithms for treatment.