Olaparib: A Review as First-Line Maintenance Therapy in Advanced Ovarian Cancer

Evaluation of Different Commercial Sealing Hemostatic Patches for Their Selection as Reservoirs for Localized Intraperitoneal Chemotherapy

Peritoneal carcinomatosis (PC) is typically treated by cytoreductive surgery (CRS) and subsequent chemotherapy. Sealing hemostatic patches (HP) are often used during these surgeries to prevent complications such as uncontrolled bleeding. These HP are made of biomaterials like oxidized cellulose or collagen with a binding agent, and beyond their usual function, they could also be used as drug delivery systems (DDS) for localized intraperitoneal chemotherapy in the tissue attached. Our first aim was to characterize and compare three different commercial HP (TachoSil®, Hemopatch®, and VerisetTM). Hemopatch® emerged as the most suitable candidate due to its combination of properties, including slow degradation, high hydrophilicity, excellent biological fluid absorption capacity, and moderate adhesive capacity alongside hemostasis. Utilizing Hemopatch® as a scaffold, we developed a new device incorporating a hyaluronic acid hydrogel loaded with cisplatin or olaparib. This approach facilitated sustained drug release for over 6 days, maintaining the anticancer efficacy of these agents on OVCAR-3 cells. In conclusion, integrating a DDS into HP shows potential for precisely delivering chemotherapeutic agents to any residual microscopic disease in PC following CRS.

Signaling pathways and targeted therapies in Ewing sarcoma

Ewing sarcoma, the second most prevalent malignant bone tumor with potential occurrence in soft tissues, exhibits a high level of aggressiveness, primarily afflicting children and adolescents. It is characterized by fusion proteins arising from chromosomal translocations. The fusion proteins induce aberrations in multiple signaling pathways and molecules, constituting a key event in oncogenic transformation. While diagnostic and therapeutic modalities have advanced in recent decades and multimodal treatments, including surgery, radiotherapy, and chemotherapy, have significantly improved survival of patients with localized tumors, patients with metastatic tumors continue to face poor prognoses. There persists a pressing need for novel alternative treatments, yet the translation of our understanding of Ewing sarcoma pathogenesis into improved clinical outcomes remains a critical challenge. Here, we provide a comprehensive review of Ewing sarcoma, including fusion proteins, various signaling pathways, pivotal pathogenetic molecules implicated in its development, and associated targeted therapies and immunotherapies. We summarize past endeavors, current advancements, and deliberate on limitations and future research directions. It is envisaged that this review will furnish novel insights into prospective treatment avenues for Ewing sarcoma.

Functional Analysis of BARD1 Missense Variants on Homology-Directed Repair in Ovarian and Breast Cancers

Women with germline BRCA1 mutations face an increased risk of developing breast and ovarian cancers. BARD1 (BRCA1 associated RING domain 1) is an essential heterodimeric partner of BRCA1, and mutations in BARD1 are also associated with these cancers. While BARD1 mutations are recognized for their cancer susceptibility, the exact roles of numerous BARD1 missense mutations remain unclear. In this study, we conducted functional assays to assess the homology-directed DNA repair (HDR) activity of all BARD1 missense substitutions identified in 55 breast and ovarian cancer samples, using the real-world data from the COSMIC and cBioPortal databases. Seven BARD1 variants (V85M, P187A, G491R, R565C, P669L, T719R, and Q730L) were confirmed to impair DNA damage repair. Furthermore, cells harboring these BARD1 variants exhibited increased sensitivity to the chemotherapeutic drugs, cisplatin, and olaparib, compared to cells expressing wild-type BARD1. These findings collectively suggest that these seven missense BARD1 variants are likely pathogenic and may respond well to cisplatin-olaparib combination therapy. This study not only enhances our understanding of BARD1's role in DNA damage repair but also offers valuable insights into predicting therapy responses in patients with specific BARD1 missense mutations.

An overview of pyridazin-3(2H)-one: a core for developing bioactive agents targeting cardiovascular diseases and cancer

Cardiovascular diseases (CVDs) and cancer are the top two leading causes of death globally. Vasodilators are commonly used to treat various CVDs. In cancer treatment, targeted anticancer agents have been developed to minimize side effects compared with traditional chemotherapy. Many hypertension patients are more prone to cancer, a case known as reverse cardio-oncology. This leads to the search for drugs with dual activity or repurposing strategy to discover new therapeutic uses for known drugs. Recently, medicinal chemists have shown great interest in synthesizing pyridazinone derivatives due to their significant biological activities in tackling these critical health challenges. This review will concentrate on pyridazin-3(2H)-one-containing compounds as vasodilators and anticancer agents, along with a brief overview of various methods for their synthesis.

Report of Cholangiocarcinoma With Transheterozygous BRCA1 and BRCA2 Co-mutation

Cholangiocarcinoma is an aggressive malignancy involving the epithelial cells of the intrahepatic, perihilar, or extrahepatic biliary tree. It is a disease that is often diagnosed late in its course and progresses quickly. Identifying genomic mutations may provide an important utility in predicting disease course and individualizing therapy for these patients. Mutations in BRCA1 or BCRCA2 genes have been increasingly documented in hepatobiliary malignancies, but they remain a relatively uncommon occurrence. Co-mutations in both BRCA1 and BRCA2 genes are even rarer, with no previously documented reports to our knowledge of BRCA co-positivity in a patient with a hepatobiliary malignancy. We present a case of a patient with cholangiocarcinoma found to have mutations in both BRCA1 and BRCA2 genes.

Combination therapy involving HSP90 inhibitors for combating cancer: an overview of clinical and preclinical progress

The molecular chaperone heat shock protein 90 (HSP90) regulates multiple crucial signalling pathways in cancer by driving the maturation of key signalling components, thereby playing a crucial role in tumorigenesis and drug resistance in cancer. Inhibition of HSP90 results in metastable conformational collapse of its client proteins and their proteasomal degradation. Considerable efforts have been devoted to the development of small-molecule inhibitors targeting HSP90, and more than 20 inhibitors have been evaluated in clinical trials for cancer therapy. However, owing to disadvantages such as organ toxicity and drug resistance, only one HSP90 inhibitor has been approved for use in clinical settings. In recent years, HSP90 inhibitors used in combination with other anti-cancer therapies have shown remarkable potential in the treatment of cancer. HSP90 inhibitors work synergistically with various anti-cancer therapies, including chemotherapy, targeted therapy, radiation therapy and immunotherapy. HSP90 inhibitors can improve the pharmacological effects of the above-mentioned therapies and reduce treatment resistance. This review provides an overview of the use of combination therapy with HSP90 inhibitors and other anti-cancer therapies in clinical and preclinical studies reported in the past decade and summarises design strategies and prospects for these combination therapies. Altogether, this review provides a theoretical basis for further research and application of these combination therapies in the treatment of cancer.

Emerging role of MYB transcription factors in cancer drug resistance

Decades ago, the viral myeloblastosis oncogene v-myb was identified as a gene responsible for the development of avian leukemia. However, the relevance of MYB proteins for human cancer diseases, in particular for solid tumors, remained basically unrecognized for a very long time. The human family of MYB transcription factors comprises MYB (c-MYB), MYBL2 (b-MYB), and MYBL1 (a-MYB), which are overexpressed in several cancers and are associated with cancer progression and resistance to anticancer drugs. In addition to overexpression, the presence of activated MYB-fusion proteins as tumor drivers was described in certain cancers. The identification of anticancer drug resistance mediated by MYB proteins and their underlying mechanisms are of great importance in understanding failures of current therapies and establishing new and more efficient therapy regimens. In addition, new drug candidates targeting MYB transcription factor activity and signaling have emerged as a promising class of potential anticancer therapeutics that could tackle MYB-dependent drug-resistant cancers in a more selective way. This review describes the correlation of MYB transcription factors with the formation and persistence of cancer resistance to various approved and investigational anticancer drugs.

Homologous Recombination Deficiency (HRD) Scoring, by Means of Two Different Shallow Whole-Genome Sequencing Pipelines (sWGS), in Ovarian Cancer Patients: A Comparison with Myriad MyChoice Assay

High-grade serous ovarian cancer (HGSOC) patients carrying the BRCA1/2 mutation or deficient in the homologous recombination repair system (HRD) generally benefit from treatment with PARP inhibitors. Some international recommendations suggest that BRCA1/2 genetic testing should be offered for all newly diagnosed epithelial ovarian cancer, along with HRD assessment. Academic tests (ATs) are continuously under development, in order to break down the barriers patients encounter in accessing HRD testing. Two different methods for shallow whole-genome sequencing (sWGS) were compared to the reference assay, Myriad. All these three assays were performed on 20 retrospective HGSOC samples. Moreover, HRD results were correlated with the progression-free survival rate (PFS). Both sWGS chemistries showed good correlation with each other and a complete agreement, even when compared to the Myriad score. Our academic HRD assay categorized patients as HRD-Deficient, HRM-Mild and HRN-Negative. These three groups were matched with PFS, providing interesting findings in terms of HRD scoring and months of survival. Both our sWGS assays and the Myriad test correlated with the patient's response to treatments. Finally, our AT confirms its capability of determining HRD status, with the advantage of being faster, cheaper, and easier to carry out. Our results showed a prognostic value for the HRD score.

Efficacy and Safety of Niraparib as First-Line Maintenance Treatment for Patients with Advanced Ovarian Cancer: Real-World Data from a Multicenter Study in China

BACKGROUND

Poly (ADP-ribose) polymerase (PARP) inhibitors are a new maintenance therapy option for patients with ovarian cancer (OC).

OBJECTIVE

To evaluate the efficacy and influencing factors of the novel PARP inhibitor niraparib for maintenance treatment of Chinese patients with advanced OC.

PATIENTS AND METHODS

In this retrospective multicenter real-world study patients with advanced OC from 15 hospitals throughout China were enrolled. The primary endpoint was progression-free survival (PFS) and the secondary endpoints included the time to treatment discontinuation and safety. Least Absolute Shrinkage and Selection Operator (LASSO) regression was used to identify possible risk factors for PFS, after which a prediction model was established to evaluate the likelihood of achieving an 18-month PFS. The relationship between the dose of niraparib and PFS was also evaluated.

RESULTS

The PFS rates of 199 patients at 6, 12, 18, 24, and 30 months were 87.4%, 75.9%, 63.6%, 56.1%, and 51.8%, respectively. LASSO regression model revealed that only age < 65 years (P = 0.011), BRCA mutations (P < 0.001), and R0 status after cytoreductive surgery (P = 0.01) were significant factors associated with prolonged PFS times. Based on the LASSO logistic regression analysis, a clinical prediction formula was developed: - 2.412 + 1.396Age≥65yr + 2.374BRCAwt + 1.387R1 + 0.793Interval≥12w + 0.178BMI>24kg/m2 which yielded a cut-off value of 0.091, an area under the curve (AUC) of 0.839 (0.763-0.916), a sensitivity of 94.3%, and an accuracy of 78.5%. A nomogram was then built to visualize the results. The major treatment-emergent adverse events of ≥ grade 3 included a platelet count decrease (19.1%), white blood cell count decrease (15.1%), neutrophil count decrease (13.1%), and anemia (18.6%). The 18-month PFS rates in patients treated with 200 mg niraparib were somewhat higher than in patients treated with 100 mg after 3-months of therapy.

CONCLUSIONS

For Chinese OC patients, niraparib, particularly at a 200 mg individual starting dose, was an effective therapy with easily manageable safety.

Cisplatin Dependent Secretion of Immunomodulatory High Mobility Group Box 1 (HMGB1) Protein from Lung Cancer Cells

High mobility group box 1 (HMGB1) is secreted from activated immune cells, necrotic cells, and certain cancers. Previous studies have reported that different patterns of post-translational modification, particularly acetylation and oxidation, mediate HMGB1 release and confer distinct extracellular HMGB1 signaling activity. Here we report that cisplatin but not carboplatin induces secretion of HMGB1 from human A549 non-small cell lung cancer (NSCLC) cells. Cisplatin-mediated HMGB1 secretion was dose-dependent and was regulated by nuclear exportin 1 (XPO1) also known as chromosomal maintenance 1 (CRM1) rather than adenosine diphosphate (ADP)-ribosylation, acetylation, or oxidation. HMGB1, as well as lysine acetylation and cysteine disulfide oxidation of secreted HMGB1, were monitored by sensitive and specific assays using immunoprecipitation, stable isotope dilution, differential alkylation, and nano liquid chromatography parallel reaction monitoring/high-resolution mass spectrometry (nano-LC-PRM/HRMS). A major fraction of the HMGB1 secreted by low-dose cisplatin treatment of A549 NSCLC cells was found to be in the fully reduced form. In contrast, mainly oxidized forms of HMGB1 were secreted by dimethyl sulfoxide (DMSO)-mediated apoptosis. These findings suggest that inhibition of XPO1 could potentiate the anti-tumor activity of cisplatin by increasing the nuclear accumulation of HMGB1 protein, an inhibitor of cisplatin DNA-adduct repair. Furthermore, low-dose cisplatin therapy could modulate the immune response in NSCLC through the established chemokine activity of extracellular reduced HMGB1. This could potentially enhance the efficacy of subsequent immunotherapy treatment.

Homologous Recombination Deficiency Score Determined by Genomic Instability in a Romanian Cohort

The Homologous Recombination Deficiency (HRD) Score, determined by evaluating genomic instability through the assessment of loss of heterozygosity (LOH), telomeric allelic imbalance (TAI), and large-scale state transitions (LST), serves as a crucial biomarker for identifying patients who might benefit from targeted therapies, such as PARP inhibitors (PARPi). This study aimed to investigate the efficacy of HRD testing in high-grade serous ovarian carcinoma, tubal, and peritoneal cancer patients who are negative for somatic BRCA1 and BRCA2 mutations and to evaluate the impact of HRD status on Bevacizumab and PARPi therapy response. A cohort of 100 Romanian female patients, aged 42-77, was initially selected. Among them, 30 patients had unsuitable samples for HRD testing due to insufficient tumor content or DNA integrity. Using the OncoScan C.N.V. platform, HRD testing was successfully performed on the remaining 70 patients, with 20 testing negative and 50 testing positive for HRD. Among the HRD-positive patients, 35 were eligible for and benefited from PARPi maintenance therapy, resulting in a median progression-free survival (PFS) increase from 4 months to 8.2 months. Our findings support the importance of HRD testing in ovarian cancer patients, demonstrating the potential therapeutic advantage of PARPi therapy in HRD-positive patients without somatic BRCA1/2 mutations.

Natural phytochemicals prevent side effects in BRCA-mutated ovarian cancer and PARP inhibitor treatment

Ovarian cancer is among the most common malignant tumors in gynecology and is characterized by insidious onset, poor differentiation, high malignancy, and a high recurrence rate. Numerous studies have shown that poly ADP-ribose polymerase (PARP) inhibitors can improve progression-free survival (PFS) in patients with BRCA-mutated ovarian cancer. With the widespread use of BRCA mutation and PARP inhibitor (PARPi) combination therapy, the side effects associated with BRCA mutation and PARPi have garnered attention worldwide. Mutations in the BRCA gene increase KEAP1-NRF2 ubiquitination and reduce Nrf2 content and cellular antioxidant capacity, which subsequently produces side effects such as cardiovascular endothelial damage and atherosclerosis. PARPi has hematologic toxicity, producing thrombocytopenia, fatigue, nausea, and vomiting. These side effects not only reduce patients' quality of life, but also affect their survival. Studies have shown that natural phytochemicals, a class of compounds with antitumor potential, can effectively prevent and treat the side effects of chemotherapy. Herein, we reviewed the role of natural phytochemicals in disease prevention and treatment in recent years, including sulforaphane, lycopene, catechin, and curcumin, and found that these phytochemicals have significant alleviating effects on atherosclerosis, nausea, and vomiting. Moreover, these mechanisms of action significantly correlated with the side-effect-producing mechanisms of BRCA mutations and PARPi. In conclusion, natural phytochemicals may be effective in alleviating the side effects of BRCA mutant ovarian cancer cells and PARP inhibitors.

The Influence of PARP, ATR, CHK1 Inhibitors on Premature Mitotic Entry and Genomic Instability in High-Grade Serous BRCAMUT and BRCAWT Ovarian Cancer Cells

Olaparib is a poly (ADP-ribose) polymerase inhibitor (PARPi) that inhibits PARP1/2, leading to replication-induced DNA damage that requires homologous recombination repair. Olaparib is often insufficient to treat BRCA-mutated (BRCA^MUT) and BRCA wild-type (BRCA^WT) high-grade serous ovarian carcinomas (HGSOCs). We examined the short-term (up to 48 h) efficacy of PARPi treatment on a DNA damage response pathway mediated by ATR and CHK1 kinases in BRCA^MUT (PEO-1) and BRCA^WT (SKOV-3 and OV-90) cells. The combination of ATRi/CHK1i with PARPi was not more cytotoxic than ATR and CHK1 monotherapy. The combination of olaparib with inhibitors of the ATR/CHK1 pathway generated chromosomal abnormalities, independent on BRCA^MUT status of cells and formed of micronuclei (MN). However, the beneficial effect of the PARPi:ATRi combination on MN was seen only in the PEO1 BRCA^MUT line. Monotherapy with ATR/CHK1 inhibitors reduced BrdU incorporation due to a slower rate of DNA synthesis, which resulted from elevated levels of replication stress, while simultaneous blockade of PARP and ATR caused beneficial effects only in OV-90 cells. Inhibition of ATR/CHK1 increased the formation of double-strand breaks as measured by increased γH2AX expression at collapsed replication forks, resulting in increased levels of apoptosis. Our findings indicate that ATR and CHK1 inhibitors provoke premature mitotic entry, leading to genomic instability and ultimately cell death.

Neuroprotective Effects of PARP Inhibitors in Drosophila Models of Alzheimer’s Disease

Alzheimer’s disease (AD) is an irreversible age-related neurodegenerative disorder clinically characterized by severe memory impairment, language deficits and cognitive decline. The major neuropathological hallmarks of AD include extracellular deposits of the β-amyloid (Aβ) peptides and cytoplasmic neurofibrillary tangles (NFTs) of hyperphosphorylated tau protein. The accumulation of plaques and tangles in the brain triggers a cascade of molecular events that culminate in neuronal damage and cell death. Despite extensive research, our understanding of the molecular basis of AD pathogenesis remains incomplete and a cure for this devastating disease is still not available. A growing body of evidence in different experimental models suggests that poly(ADP-ribose) polymerase-1 (PARP-1) overactivation might be a crucial component of the molecular network of interactions responsible for AD pathogenesis. In this work, we combined genetic, molecular and biochemical approaches to investigate the effects of two different PARP-1 inhibitors (olaparib and MC2050) in Drosophila models of Alzheimer’s disease by exploring their neuroprotective and therapeutic potential in vivo. We found that both pharmacological inhibition and genetic inactivation of PARP-1 significantly extend lifespan and improve the climbing ability of transgenic AD flies. Consistently, PARP-1 inhibitors lead to a significant decrease of Aβ42 aggregates and partially rescue the epigenetic alterations associated with AD in the brain. Interestingly, olaparib and MC2050 also suppress the AD-associated aberrant activation of transposable elements in neuronal tissues of AD flies.

Assay technologies facilitating drug discovery for ADP-ribosyl writers, readers and erasers

ADP-ribosylation is a post-translational modification catalyzed by writer enzymes - ADP-ribosyltransferases. The modification is part of many signaling events, can modulate the function and stability of target proteins, and often results in the recruitment of reader proteins that bind to the ADP-ribosyl groups. Erasers are integral actors in these signaling events and reverse the modification. ADP-ribosylation can be targeted with therapeutics and many inhibitors against writers exist, with some being in clinical use. Inhibitors against readers and erasers are sparser and development of these has gained momentum only in recent years. Drug discovery has been hampered by the lack of specific tools, however many significant advances in the methods have recently been reported. We discuss assays used in the field with a focus on methods allowing efficient identification of small molecule inhibitors and profiling against enzyme families. While human proteins are focused, the methods can be also applied to bacterial toxins and virus encoded erasers that can be targeted to treat infectious diseases in the future.