Using PARP Inhibitors in the Treatment of Patients With Ovarian Cancer

Clinical availability and characteristics of multigene panel testing for recurrent/advanced gynecologic cancer

BACKGROUND

Japan's health insurance covers multigene panel testing. This study aimed to determine the potential availability and utility of gene panel testing clinically in gynecologic oncology.

METHODS

We analyzed the characteristics of patients with gynecologic cancer who underwent gene panel testing using FoundationOne® CDx or OncoGuide™ NCC Oncopanel between November 2019 and October 2022.

RESULTS

Out of 102 patients analyzed, 32, 18, 43, 8, and 1 had cervical, endometrial, ovarian cancers, sarcoma, and vaginal cancer, respectively. Druggable gene alteration was found in 70 patients (68.6%; 21 with cervical cancer, 15 with endometrial cancer, 28 with ovarian cancer, 5 with sarcoma, and 1 with other). The most common druggable gene alteration was PIK3CA mutation (n = 21), followed by PTEN mutation (n = 12) and high tumor mutation burden (TMB-H) (n = 11). TMB-H was detected in 5 patients with cervical cancer, 5 with endometrial cancer, and 1 with endometrial stromal sarcoma. Eleven patients (10.8%) received molecularly targeted therapy according to their gene aberrations. Gene panel testing was mostly performed when the second-line treatment was ineffective. Of all 102 patients, 60 did not have recommended treatment, and 15 died or had worsened conditions before obtaining the test results.

CONCLUSION

Through multigene panel testing, although many patients had druggable gene alterations, 10.8% of them received the recommended treatment. TMB-H was mainly observed in cervical/endometrial cancer, suggesting its potential as a therapeutic biomarker of immune checkpoint inhibitors. Furthermore, patients' prognosis and performance status should be considered before performing the test.

The combination therapy of isomucronulatol 7-O-beta-glucoside (IMG) and CEP-9722 targeting ferroptosis-related biomarkers in non-small cell lung cancer (NSCLC)

BACKGROUND

NSCLC is a malignant tumor with a high incidence. Ferroptosis presents an essential function in regulating carcinogenesis and tumor progression. However, the ferroptosis-associated prognostic model based on single-cell sequencing of NSCLC remains unexplored. Our study aims to establish a potential predictive model for NSCLC patients and provide available targeted drugs for clinical treatment.

METHODS

The data on NSCLC patients were collected from TCGA and GEO databases to analyze their gene expression profiles. ConsensusCluster was adopted to divide the patients into different groups based on ferroptosis-related genes. Then, the univariable Cox and LASSO analyses were applied to data analysis and model establishment. Single-cell analysis was used to explore the risk score genes in different cell populations and states. The protein levels of these genes were also investigated through the HPA database. Drug sensitivity was evaluated in CellMiner database. CCK8 and colony formation assays were performed to validate potential drugs' effects on lung cancer cell lines.

RESULTS

A ferroptosis-related prognostic model involving 14 genes in NSCLC patients was established. The risk score model was developed in training set GSE31210 and validated in the test set TCGA. The low-risk score group showed a better prognosis than the high-risk score group. The single-cell analysis revealed that the risk score genes were mainly derived from lung tumor cells. Most risk score genes were more highly expressed in tumor tissue than in normal tissue, according to the HPA database. Besides, these genes were associated with 106 drugs in CellMiner database. Finally, the drug effects on NSCLC cell growth were evaluated by cck8 and colony formation.

CONCLUSIONS

We identified an effective ferroptosis-related prognostic model based on single-cell sequencing. The potential prediction model is devoted to exploring clinical therapeutic targets for NSCLC.

A Case of Niraparib PARP-Inhibitor Induced Sweet Syndrome in Gynecologic Cancer

Sweet Syndrome, or acute febrile neutrophilic dermatosis, is a rare inflammatory dermatologic disorder that can be spontaneous, associated with malignancy, or drug-induced. Reports of Sweet Syndrome in gynecologic oncology patients are sparse, and the majority are thought to be malignancy-associated. The case presented here represents the third case of drug-induced Sweet Syndrome in a gynecologic oncology patient. To the best of our knowledge, this is the first report of Sweet Syndrome after initiation of a poly (ADP-ribose) polymerase inhibitor (PARPi) for maintenance therapy in the treatment of high grade serous ovarian carcinoma (HGSOC). This represents one of the most severe dermatologic adverse effects of treatment with PARPi reported to date, requiring treatment discontinuation.

PARP inhibitors in the treatment of ARID1A mutant ovarian clear cell cancer: PI3K/Akt1-dependent mechanism of synthetic lethality

Introduction

Poly(ADP-ribose) polymerase (PARP) is a nuclear enzyme involved in the repair of DNA single-strand breaks (SSB). The recent development of poly(ADP-ribose) polymerase inhibitors (PARPi) results from over 45 years of studies. When the activity of PARP1 or PARP2 is compromised, DNA SSB lesions are unresolved and can be converted to DNA double-strand breaks (DSBs) by the cellular transcription mechanisms. ARID1A (also called BAF250a) is an important component of the mammalian Switch/Sucrose Non-Fermentable (SWI/SNF) chromatin-remodeling complex. ARID1A gene demonstrates >50% of mutation rate in ovarian clear-cell carcinomas (OCCC). Mutated or downregulated ARID1A significantly compromises the Homologous Recombination Repair (HRR) of DNA DSB.

Results

The present study demonstrated that downregulated or mutated ARID1A attenuates DNA HRR through stimulation of the PI3K/Akt1 pathway and makes tumor cells highly sensitive to PARPi and PARPi/ionizing radiation (IR) combination. We showed that PI3K/Akt1 pathway plays an important role in the sensitization of cancer cell lines with compromised function of ARID1A to PARPi treatment.

Discussion

We believe that using of PARPi monotherapy or in combination with radiation therapy is an appealing strategy for treating ARID1A-mutated cancers, as well as many other types of PI3K/Akt1-driven cancers.

Somatic gene mutations in malignant steroid cell tumours and response to multiple treatments

Malignant ovarian steroid cell tumours are a rare subgroup of sex cord-stromal tumours. There are no systematic reviews on the associated treatments, and little is known about their genomic profile. We describe a case of a pelvic malignant ovarian steroid cell tumour in a premenopausal woman in her 40s. She received cytoreductive surgery and six cycles of paclitaxel+carboplatin+bevacizumab. After recurrence, the tumour was surgically removed again, followed by radiation and hormone blockade therapy. Complete remission was achieved after treatment with bleomycin, etoposide and cisplatin. She remained in a platinum-sensitive relapse state and subsequently received maintenance therapy with olaparib. Since the tumour was initially refractory to treatment, tissue specimens were screened for gene mutations using a next-generation sequencing oncology panel and a somatic variant detection system, which revealed somatic gene mutations in ARID1A, PIK3CA, TERT and ATM, some of which are involved in DNA repair.

Secondary erythrocytosis following drugs used in rifampicin/multidrug-resistant tuberculosis: a retrospective cohort study

Background

Multidrug-resistant tuberculosis (MDR-TB) drugs have never been associated with erythrocytosis. In Eritrea, however, several cases of incident erythrocytosis had been observed in the MDR-TB hospital. This study was aimed at exploring the association between MDR-TB drugs and secondary erythrocytosis, characterising the cases, and identifying other possible risk factors.

Methods

A retrospective cohort study was conducted in Merhano National Referral MDR-TB hospital. Data were extracted from physically available clinical cards and laboratory results collected longitudinally between 23 June 2011 and 17 January 2021. Initially, univariate descriptive statistics (frequency, mean (SD), median (IQR) and range) were used as appropriate. Then, χ² or Fisher χ² test, and bivariate and/or multivariate Cox proportional hazard model were used to identify the predictors of incident erythrocytosis. All statistical analyses were conducted using R, and a two-sided alpha 0.05 was used to determine the statistical significance.

Results

A total of 257 patients’ medical cards were screened, and 219 were eligible for further analysis. The median age of the patients was 38 years (range: 13–90 years) and 54.8% were males. During the follow-up time, 31 (14.2%) patients developed secondary erythrocytosis yielding an incidence rate of 7.8 cases per 1000 person-months. On average, the median time to onset of the event was found to be 5-months (range: 1–24 months). Males were more likely to develop the event than females (adjusted HR=7.13, 95% CI=1.66 to 30.53), and as body weight increases by 1 kg, the likelihood of developing secondary erythrocytosis was found to increase by 7% (adjusted HR=1.07, 95% CI=1.03 to 1.10). Moreover, all cases of secondary erythrocytosis were found to be possibly associated with the MDR-TB drugs.

Conclusion

The authors hypothesised that the incident erythrocytosis is possibly be associated with MDR-TB drugs, and further studies are required to substantiate this finding.

Loss of ATRX confers DNA repair defects and PARP inhibitor sensitivity

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Drug screen shows that ATRX KO leads to PARP inhibitor sensitivity in glioma cells.

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PARPi leads to greater levels of replication stress in ATRX KO cells than WT.

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IDH1 R132H and ATRX KO have similar levels of PARP inhibitor sensitivity.

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ATRi and PARPi have greater synergy in ATRX KO cells.

Alpha Thalassemia/Mental Retardation Syndrome X-Linked (ATRX) is mutated frequently in gliomas and represents a potential target for cancer therapies. ATRX is known to function as a histone chaperone that helps incorporate histone variant, H3.3, into the genome. Studies have implicated ATRX in key DNA damage response (DDR) pathways but a distinct role in DNA repair has yet to be fully elucidated. To further investigate the function of ATRX in the DDR, we created isogenic wild-type (WT) and ATRX knockout (KO) model cell lines using CRISPR-based gene targeting. These studies revealed that loss of ATRX confers sensitivity to poly(ADP)-ribose polymerase (PARP) inhibitors, which was linked to an increase in replication stress, as detected by increased activation of the ataxia telangiectasia and Rad3-related (ATR) signaling axis. ATRX mutations frequently co-occur with mutations in isocitrate dehydrogenase-1 and -2 (IDH1/2), and the latter mutations also induce HR defects and PARP inhibitor sensitivity. We found that the magnitude of PARP inhibitor sensitivity was equal in the context of each mutation alone, although no further sensitization was observed in combination, suggesting an epistatic interaction. Finally, we observed enhanced synergistic tumor cell killing in ATRX KO cells with ATR and PARP inhibition, which is commonly seen in HR-defective cells. Taken together, these data reveal that ATRX may be used as a molecular marker for DDR defects and PARP inhibitor sensitivity, independent of IDH1/2 mutations. These data highlight the important role of common glioma-associated mutations in the regulation of DDR, and novel avenues for molecularly guided therapeutic intervention.

Effect of PARP Inhibitors as Maintenance Treatment on Restricted Mean Survival Time in Platinum-Sensitive Recurrent Ovarian Cancer: A Systematic Review and Meta-analysis

BACKGROUND

Earlier trials on the efficacy of poly (ADP-ribose) polymerase (PARP) inhibitors in platinum-sensitive relapsed ovarian cancer used the hazard ratio (HR) as an efficacy parameter.

OBJECTIVE

The present meta-analysis was focused on improving the robustness and clinical interpretability of the efficacy evaluation of PARP inhibitors using the restricted mean survival time (RMST).

METHODS

A search for relevant studies published up to July 31, 2020, was performed in electronic databases to identify eligible trials comparing PARP inhibitors with placebo. The difference in RMST was used as a PARP inhibitor efficacy parameter. Combined differences in RMST with 95% CIs across studies were calculated using a random-effects model.

RESULTS

Four trials (6 articles) were assessed, including 1079 patients treated with PARP inhibitors and 598 with placebo. The combined RMST differences for up to 360 days (PARP inhibitors minus placebo: point estimate and 95% CI) among all patients and the patients of subgroups with BRCA mutations, homologous recombination-deficient (HRD) carcinoma, and BRCA wild-type carcinoma were 87 days (95% CI = 71, 102), 112 days (95% CI = 96, 129), 99 days (95% CI = 80, 119), and 69 days (95% CI = 47, 92), respectively. The combined RMST differences for up to 660 and 720 days were also larger among patients with BRCA mutations than among those with HRD carcinoma.

CONCLUSION AND RELEVANCE

Based on using the RMST difference as an alternative measure to the HR, this meta-analysis suggests that PARP inhibitors are the most effective for patients with BRCA mutations, followed by patients with HRD carcinoma.

Poly (ADP-ribose) polymerase (PARP) as target for the treatment of epithelial ovarian cancer: what to know

INTRODUCTION

Poly (ADP-ribose) polymerase (PARP) inhibitors are being developed in maintenance and recurrence treatment settings of epithelial ovarian cancers (EOCs) with BRCA 1-2 gene mutation. PARP inhibitors are the first example of drugs targeting the loss of a gene suppressor: they block base-excision repair in the cancer cells, which have lost homologous recombination due to BRCA-mutation, resulting in loss of DNA repair and cell death, also known as synthetic lethality.

AREAS COVERED

This article provides an overview of PARP inhibitors in OC treatment and also an extensive section on the combined strategies of PARP inhibitors, including approved as well as currently investigated drugs. It also offers a section on the use of predictive biomarkers for PARP inhibitors treatment. Ongoing trials, including novel combinations, are discussed.

EXPERT OPINION

In recent years, there is increasing evidence that PARP inhibitor therapy can have life-long percussion in the treatment of EOC, even if some questions have to be solved yet, such as its use in combination therapy, the possibility to retreat with a PARP inhibitor, and finally how to overcome a resistance mechanism to this therapy. In this way, PARP inhibitors can obtain an important role in making a personalized therapeutic program in the case of first-line, neoadjuvant, platinum-sensitive, and resistant high-grade serous OC treatment.

Mutations in DNA Repair Genes and Clinical Outcomes of Patients With Metastatic Colorectal Cancer Receiving Oxaliplatin or Irinotecan-containing Regimens

OBJECTIVES

First-line regimens in the treatment of metastatic colorectal cancer (mCRC) combine a fluoropyrimidine with oxaliplatin (FOLFOX/XELOX) or irinotecan (FOLFIRI). There is limited efficacy data to guide the selection of one treatment over the other. This study investigated whether mutations affecting DNA damage response (DDR) could differentially influence the response to oxaliplatin and irinotecan-containing regimens.

METHODS

We retrospectively analyzed 49 patients with mCRC for whom treatment outcomes and results of comprehensive genomic profiling of tumors were available. Specimens with at least 1 pathogenic mutation involving BRCA1, BRCA2, ATM, BARD1, BRIP1, CDK12, CHEK1, CHEK2, FANCL, PALB2, PPP2R2A, RAD51B, RAD51C, RAD51D, or RAD54L were classified as DDR-mutated, while those without mutations were DDR-wild-type (WT). We compared the overall survival (OS), disease control rate, and response rate (RR) between the DDR-mutated and DDR-WT groups.

RESULTS

DDR mutations occurred in 11 patients (22%). First-line treatment with an oxaliplatin-containing regimen was administered to 33 patients (31 FOLFOX, 2 XELOX), while 16 patients received FOLFIRI. Among DDR-mutated cases, first-line treatment with FOLFOX/XELOX correlated with a statistically significant improvement in median OS compared with FOLFIRI (3.4 vs.1.8 y; P=0.042) and numerically higher RR (50% vs. 33%; P=0.58). No significant difference in OS (2.4 vs. 2.5 y; P=0.42), RR, disease control rate was observed between the 2 regimens in patients with DDR-WT tumors.

CONCLUSIONS

Mutations in DDR genes were present in 22% of patients with mCRC. In patients with DDR-mutated tumors, initial treatment with FOLFOX/XELOX correlated with improved OS and a numerically higher RR compared with FOLFIRI.

BRCA1 and BRCA2 mutations in ovarian cancer patients from Belarus: update

Background

Mutations in BRCA1 and BRCA2 are well-established risk factors for breast and ovarian cancer. In Central-Eastern European counties, the founder mutations in the BRCA1 are responsible for a significant proportion of ovarian cancer cases, however, regional differences in the frequencies of various mutations may exist. The spectrum and frequency of BRCA1/2 mutations between ovarian cancer patients have not yet been precisely established in Belarus.

Methods

Two hundred fourteen consecutive unselected cases of ovarian cancer patients from the region of West Belarus were examined. We studied 13 founder mutations in BRCA1 (c.5266dupC, c.4035delA, c.5251C > T, c.181 T > G, c.676delT, c.68_69delAG, c.3700_3704delGTAAA, c.1687C > T, c.3756_3759delGTCT) and in BRCA2 (c.658_659delGT, c.7913_7917delTTCCT, c.3847_3848delGT, c.5946delT) characteristic for Central European population.

Results

A BRCA1 or BRCA2 founder mutations were detected in 54 of the 214 (25.2%) ovarian cancer cases. The BRCA1 c.5266dupC mutation was detected in 28 patients, followed by c.4035delA mutation observed in 18 patients. BRCA1 c.3756_3759delGTCT, c.68_69delAG, and c.1687C > T were found in 3, 2, and 1 women, respectively. BRCA2 c.658_659delGT mutation was detected in 2 ovarian cancer patients. The median age of diagnosis of the 54 hereditary ovarian cancers was 57.5 years.

Conclusions

The frequency of 13 causative BRCA1 and BRCA2 founder mutations in West Belarus was higher than in other Slavic countries. Testing of BRCA1 (c.5266dupC, c.4035delA, c.3756_3759delGTCT, c.68_69delAG, c.1687C > T as well as c.181 T > G) and BRCA2 (c.658_659delGT) mutations should be considered an inexpensive and sensitive test panel for this population.

PARP Inhibitors and Prostate Cancer: To Infinity and Beyond BRCA

The U.S. Food and Drug Administration recently approved two poly-adenosine diphosphate-ribose polymerase (PARP) inhibitors, olaparib and rucaparib, for treatment of biomarker-positive metastatic castrate resistant prostate cancer. The benefits of PARP inhibition have been well characterized in patients who have BRCA1 and BRCA2 mutations in several forms of cancer. BRCA1 and BRCA2 occupy key roles in DNA damage repair, which is comprised of several different pathways with numerous participants. Patients with mutations in other key genes within the DNA damage repair pathway may also respond to treatment with PARP inhibitors, and identification of these alterations could significantly increase the percentage of patients that may benefit from PARP inhibition. This review focuses on the potential for synthetically lethal interactions between PARP inhibitors and non-BRCA DNA damage repair genes. IMPLICATIONS FOR PRACTICE: The treatment potential of PARP inhibition has been well characterized in patients with BRCA1 and BRCA2 mutations, but there is compelling evidence for expanding the use of PARP inhibitors to mutations of other non-BRCA DNA damage repair (DDR) genes. This could increase the percentage of patients that may benefit from treatment with PARP inhibitors alone or in combination with other therapies. Understanding the significance of PARP inhibitor-sensitizing alterations in other common non-BRCA DDR genes will help guide clinical decisions to provide targeted treatment options to a wider population of patients.

BRCA in Gastrointestinal Cancers: Current Treatments and Future Perspectives

A strong association between pancreatic cancer and BRCA1 and BRCA2 mutations is documented. Based on promising results of breast and ovarian cancers, several clinical trials with poly (ADP-ribose) polymerase inhibitors (PARPi) are ongoing for gastrointestinal (GI) malignancies, especially for pancreatic cancer. Indeed, the POLO trial results provide promising and awaited changes for the pancreatic cancer therapeutic landscape. Contrariwise, for other gastrointestinal tumors, the rationale is currently only alleged. The role of BRCA mutation in gastrointestinal cancers is the subject of this review. In particular, we aim to provide the latest updates about novel therapeutic strategies that, exploiting DNA repair defects, promise to shape the future therapeutic scenario of GI cancers.

TACC3 expression as a prognostic factor in aggressive types of adult T-cell leukemia/lymphoma patients

INTRODUCTION

Adult T-cell leukemia/lymphoma (ATLL) is a malignant peripheral T-cell neoplasm associated with human T-cell leukemia virus type-1 (HTLV-1). The acute and lymphoma subtypes are regarded as aggressive ATLLs, and the overall survival (OS) of patients remains poor. Transforming acidic coiled-coil-containing protein 3 (TACC3) regulates microtubules, which are associated with cancer-related proteins overexpressed in various cancers. Such a relationship has not been reported in hematopoietic tumors, including ATLL.

METHODS

We examined tissue microarrays of histological samples from 92 cases of aggressive ATLL and assessed clinical features, including TACC3 protein expression levels.

RESULTS

Compared with TACC3-low, TACC3-high ATLL patients were significantly older (P < .001), with a tendency toward pleomorphic variant over other morphological classifications (P = .019). TACC3-high patients (median survival time [MST] 10.6 months, confidence interval [CI] [6.27-15.6]) had poorer OS compared to TACC3-low patients (MST 20 months, CI [9.43-38.5]) (P = .0168). Moreover, multivariate analysis on TACC3 expression levels suggests that TACC3-high is an independent significant prognostic factor (HR, 1.700; 95% CI, 1.037-2.753; P = .0355).

CONCLUSION

Certain drugs that inhibit TACC3-overexpressing neoplastic cells are used clinically. Further studies might highlight a key role for TACC3 in the oncogenesis and progression of ATLL.

Successful Treatment of Patients with Refractory High-Grade Serous Ovarian Cancer with GOPC-ROS1 Fusion Using Crizotinib: A Case Report

BACKGROUND

Recently, multiple poly (ADP-ribose) polymerase (PARP) inhibitors have demonstrated excellent efficacy among patients with ovarian cancer with or without BRCA mutations. However, alternative therapeutic options are urgently required for patients who cannot benefit from conventional chemotherapy or PARP inhibitors.

CASE PRESENTATION

A patient with high-grade serous ovarian carcinoma presented to our clinic after developing resistance to chemotherapy. Paired tumor-normal next-generation sequencing (NGS) was performed using peripheral blood to identify potential actionable mutations. NGS revealed the patient harboring a GOPC-ROS1 fusion, which was subsequently verified using a reverse transcription polymerase chain reaction assay. No germline or somatic mutation in BRCA1/2 or mismatch repair genes was detected. Therefore, the patient received crizotinib treatment. A rapid, favorable clinical response (partial response at 1 month) was observed, with further pathological response monitored and evaluated in follow-up interrogation.

CONCLUSION

This study suggested that crizotinib was an off-the-shelf, practical, and ostensibly effective treatment option for patients with ovarian cancer with ROS1 rearrangement. NGS-based genetic testing may guide to plan therapeutic paradigms, and render precision medicine promising in ovarian cancer treatment.

IMPLICATIONS FOR PRACTICE

Despite the previous report of ROS1 fusion in patients with ovarian cancer, it remains unknown whether patients can benefit from targeted therapeutic drugs. This study reports a GOPC-ROS1 fusion identified by next-generation sequencing in a patient with chemotherapy-resistant ovarian cancer. The patient was administered crizotinib and showed rapid, remarkable response. This study suggests that comprehensive sequencing should be offered for patients with ovarian cancer without effective therapeutic strategies, and crizotinib can be used to treat ROS1-rearranged ovarian carcinomas.

Decoding the evolutionary response to prostate cancer therapy by plasma genome sequencing

BACKGROUND

Investigating genome evolution in response to therapy is difficult in human tissue samples. To address this challenge, we develop an unbiased whole-genome plasma DNA sequencing approach that concurrently measures genomic copy number and exome mutations from archival cryostored plasma samples. This approach is applied to study longitudinal blood plasma samples from prostate cancer patients, where longitudinal tissue biopsies from the bone and other metastatic sites have been challenging to collect.

RESULTS

A molecular characterization of archival plasma DNA from 233 patients and genomic profiling of 101 patients identifies clinical correlations of aneuploid plasma DNA profiles with poor survival, increased plasma DNA concentrations, and lower plasma DNA size distributions. Deep-exome sequencing and genomic copy number profiling are performed on 23 patients, including 9 patients with matched metastatic tissues and 12 patients with serial plasma samples. These data show a high concordance in genomic alterations between the plasma DNA and metastatic tissue samples, suggesting the plasma DNA is highly representative of the tissue alterations. Longitudinal sequencing of 12 patients with 2-5 serial plasma samples reveals clonal dynamics and genome evolution in response to hormonal and chemotherapy. By performing an integrated evolutionary analysis, minor subclones are identified in 9 patients that expanded in response to therapy and harbored mutations associated with resistance.

CONCLUSIONS

This study provides an unbiased evolutionary approach to non-invasively delineate clonal dynamics and identify clones with mutations associated with resistance in prostate cancer.

Apomorphine facilitates loss of respiratory chain activity in human epithelial ovarian cancer and inhibits angiogenesis in vivo

Apomorphine, a therapeutic agent for neurological diseases, is structurally similar to dopamine, and thereby holds potential in cancer therapy. However, there are no reports regarding its anti-cancer effects on human epithelial ovarian cancers (EOCs); therefore, we aimed to elucidate the mechanism underlying its action after drug repositioning. Apomorphine inhibited the proliferation of ES2 and OV90 EOC cells by inducing caspase activation and mitochondrion-associated apoptosis; it also promoted endoplasmic reticulum stress and mitochondrial dysfunction through mitochondrial membrane potential depolarization and mitochondrial calcium overload. Moreover, following apomorphine treatment, we noted the loss of respiratory chain activity by reduction of oxidative phosphorylation and energy-production shift in EOC cells. Further, we verified the anti-angiogenic capacity of apomorphine using fli:eGFP transgenic zebrafish. As a preclinical assessment, we demonstrated the synergistic anti-cancer effects of apomorphine and paclitaxel combination.

Current and future strategies for treatment of ovarian clear cell carcinoma

Ovarian clear cell carcinoma (OCCC) is one of the five histological types of epithelial ovarian cancer (EOC). OCCC comprises 23% of all EOC cases in Japan, whereas the rate of OCCC in North America and Europe is much lower. OCCC is generally categorized as a rare gynecologic malignancy, and there is limited evidence for specific treatment. The clinical basis for treatment of OCCC is mostly based on retrospective studies, many of which were performed in Japan. Until recently, most randomized clinical trials for EOC have included OCCC; therefore, current treatment for OCCC is basically the same as that for other histologic types of EOC. However, the clinical characteristics of OCCC differ from those of high-grade serous carcinoma, particularly for chemosensitivity, and there is a need to develop new treatment for OCCC. The molecular background of OCCC has unique features: tumors are usually negative for p53 mutations and positive for ARID1A and/or PIK3CA mutations, whereas p53 mutations are common in high-grade serous or endometrioid carcinomas. These features may help in development of new treatment for OCCC. In this review, we described the current evidence for treatment of OCCC, including surgery, radiotherapy, chemotherapy, molecular targeted therapy and immunotherapy, and we discuss ongoing clinical trials and preclinical studies of new treatment approaches for OCCC.

Genomic Signatures of Immune Activation Predict Outcome in Advanced Stages of Ovarian Cancer and Basal-Like Breast Tumors

There is an unmet need for new therapies in metastatic ovarian cancer and basal-like breast cancer since no curative therapies are currently available. Immunotherapy has shown to be active in several solid tumors, but particularly more in those where a pre-activated immune state does exist. In this work, we aim to identify biomarkers that could distinguish immune-activated tumors and predict response to therapies in ovarian and basal-like breast cancer, as well as their association with the level of tumor immune infiltration. We found that the combined expression of IFNG, CD30, CXCL13, and PRF1 correlated with better overall survival (OS) in advanced stage ovarian cancer. This was confirmed using an independent dataset from TCGA. Interestingly, we observed that this gene combination also predicted for better prognosis in ovarian tumors with low mutational load, which typically respond less to immunotherapy. Expression of IFNG, CD30, CXCL13, and PRF1 was associated with increased level of immune infiltrates (CD8⁺ T cells, dendritic cells, and neutrophils) within the tumor. Moreover, we found that these gene signature also correlated with an increased OS and with a higher level of tumor immune infiltrates (B cells, CD8⁺ T cells, CD4⁺ T cells, neutrophils, and dendritic cells) in basal-like breast cancer. In conclusion, our analysis identifies genes signatures with potential to recognize immune activated ovarian and basal-like breast cancers with favorable prognosis and with a remarkable predictive capacity in tumors with low mutational burden. The presented results led to a hypothesis being formulated, but prospective clinical studies are needed to support a potential clinical application.

WIP1 Promotes Homologous Recombination and Modulates Sensitivity to PARP Inhibitors

Genotoxic stress triggers a combined action of DNA repair and cell cycle checkpoint pathways. Protein phosphatase 2C delta (referred to as WIP1) is involved in timely inactivation of DNA damage response by suppressing function of p53 and other targets at chromatin. Here we show that WIP1 promotes DNA repair through homologous recombination. Loss or inhibition of WIP1 delayed disappearance of the ionizing radiation-induced 53BP1 foci in S/G2 cells and promoted cell death. We identify breast cancer associated protein 1 (BRCA1) as interactor and substrate of WIP1 and demonstrate that WIP1 activity is needed for correct dynamics of BRCA1 recruitment to chromatin flanking the DNA lesion. In addition, WIP1 dephosphorylates 53BP1 at Threonine 543 that was previously implicated in mediating interaction with RIF1. Finally, we report that inhibition of WIP1 allowed accumulation of DNA damage in S/G2 cells and increased sensitivity of cancer cells to a poly-(ADP-ribose) polymerase inhibitor olaparib. We propose that inhibition of WIP1 may increase sensitivity of BRCA1-proficient cancer cells to olaparib.

Operationalization of Next-Generation Sequencing and Decision Support for Precision Oncology

Genomic testing has become a part of routine oncology care and plays critical roles in diagnosis, prognostic assessment, and treatment selection. Thus, in parallel, the variety of genomic testing providers and sequencing platforms has grown exponentially. Selection of the best-fit panel for each case can be daunting, with many factors to consider. Among them is whether alteration interpretation and therapy/clinical trial matching are included and/or sufficient. In this article, we review some common commercially available sequencing platforms for the genes and types of alterations tested, samples needed, and reporting content provided. We review publicly available resources for a do-it-yourself approach to alteration interpretation when it is not provided or when supplemental research is needed, along with resources to identify genomically matched treatment options that are approved and/or investigational. However, with both commercially provided interpretation and publicly available resources, there are still caveats and limitations that can stem from insufficient or ambiguous nomenclature as well as from the presentation of information. Use cases in which clinical decision making was affected are discussed. After treatment options are identified, it is important to assess the level of evidence for use within the patient's tumor type and molecular profile. However, numerous level-of-evidence scales have been published in recent years, so we provide a publicly available tool to facilitate interoperability. The level of evidence, along with other factors, such as allelic frequency and copy number, can be used to prioritize treatment options when multiple are identified.

The oncoprotein DEK affects the outcome of PARP1/2 inhibition during mild replication stress

DNA replication stress is a major source of genomic instability and is closely linked to tumor formation and progression. Poly(ADP-ribose)polymerases1/2 (PARP1/2) enzymes are activated in response to replication stress resulting in poly(ADP-ribose) (PAR) synthesis. PARylation plays an important role in the remodelling and repair of impaired replication forks, providing a rationale for targeting highly replicative cancer cells with PARP1/2 inhibitors. The human oncoprotein DEK is a unique, non-histone chromatin architectural protein whose deregulated expression is associated with the development of a wide variety of human cancers. Recently, we showed that DEK is a high-affinity target of PARylation and that it promotes the progression of impaired replication forks. Here, we investigated a potential functional link between PAR and DEK in the context of replication stress. Under conditions of mild replication stress induced either by topoisomerase1 inhibition with camptothecin or nucleotide depletion by hydroxyurea, we found that the effect of acute PARP1/2 inhibition on replication fork progression is dependent on DEK expression. Reducing DEK protein levels also overcomes the restart impairment of stalled forks provoked by blocking PARylation. Non-covalent DEK-PAR interaction via the central PAR-binding domain of DEK is crucial for counteracting PARP1/2 inhibition as shown for the formation of RPA positive foci in hydroxyurea treated cells. Finally, we show by iPOND and super resolved microscopy that DEK is not directly associated with the replisome since it binds to DNA at the stage of chromatin formation. Our report sheds new light on the still enigmatic molecular functions of DEK and suggests that DEK expression levels may influence the sensitivity of cancer cells to PARP1/2 inhibitors.

Perspectives on PARPs in S Phase

Accurate copying of DNA during S phase is essential for genome stability and cell viability. During genome duplication, the progression of the DNA replication machinery is challenged by limitations in nucleotide supply and physical barriers in the DNA template that include naturally occurring DNA lesions and secondary structures that are difficult to replicate. To ensure correct and complete replication of the genome, cells have evolved several mechanisms that protect DNA replication forks and thus maintain genome integrity and stability during S phase. One class of enzymes that have recently emerged as important in this process, and therefore as promising targets in anticancer therapy, are the poly(ADP-ribose) polymerases (PARPs). We review here the roles of these enzymes during DNA replication as well as their impact on genome stability and cellular viability in normal and cancer cells.

Adaptive responses in a PARP inhibitor window of opportunity trial illustrate limited functional interlesional heterogeneity and potential combination therapy options

Poly (ADP-ribose) polymerase inhibitor (PARPi)-based combination therapies are demonstrating efficacy in patients, however, identifying the right combination for the right patient remains a critical challenge. Thus, it is urgent to develop approaches able to identify patients likely to benefit from specific combination therapies. Several groups, including ours, have demonstrated that targeting adaptive responses induced by PARPi increases depth and duration of response. In this study, we instituted a talazoparib (PARPi) monotherapy window of opportunity trial to identify informative adaptive responses in high grade serous ovarian cancer patients (HGSOC). Patients were treated for 7 to 14 days with PARPi monotherapy prior to surgery with tissue samples from multiple sites being collected pre- and post-treatment in each patient. Analysis of these samples demonstrated that individual patients displayed different adaptive responses with limited interlesional heterogeneity. Ability of combination therapies designed to interdict adaptive responses to decrease viability was validated using model systems. Thus, assessment of adaptive responses to PARPi provides an opportunity for patient-specific selection of combination therapies designed to interdict patient-specific adaptive responses to maximize patient benefit.

Alterations in DNA Damage Repair Genes in Primary Liver Cancer

PURPOSE

Alterations in DNA damage repair (DDR) genes produce therapeutic biomarkers. However, the characteristics and significance of DDR alterations remain undefined in primary liver cancer (PLC).

EXPERIMENTAL DESIGN

Patients diagnosed with PLC were enrolled in the trial (PTHBC, NCT02715089). Tumors and matched blood samples from participants were collected for a targeted next-generation sequencing assay containing exons of 450 cancer-related genes, including 31 DDR genes. The OncoKB knowledge database was used to identify and classify actionable alterations, and therapeutic regimens were determined after discussion by a multidisciplinary tumor board.

RESULTS

A total of 357 patients with PLC were enrolled, including 214 with hepatocellular carcinoma, 122 with ICC, and 21 with mixed hepatocellular-cholangiocarcinoma. A total of 92 (25.8%) patients had at least one DDR gene mutation, 15 of whom carried germline mutations. The most commonly altered DDR genes were ATM (5%) and BRCA1/2 (4.8%). The occurrence of DDR mutations was significantly correlated with a higher tumor mutation burden regardless of the PLC pathologic subtype. For DDR-mutated PLC, 26.1% (24/92) of patients possessed at least one actionable alteration, and the actionable frequency in DDR wild-type PLC was 18.9% (50/265). Eight patients with the BRCA mutation were treated by olaparib, and patients with BRCA2 germline truncation mutations showed an objective response.

CONCLUSIONS

The landscape of DDR mutations and their association with genetic and clinicopathologic features demonstrated that patients with PLC with altered DDR genes may be rational candidates for precision oncology treatment.

Homologous recombination defects and how they affect replication fork maintenance

Homologous recombination (HR) repairs DNA double strand breaks (DSBs) and stabilizes replication forks (RFs). RAD51 is the recombinase for the HR pathway. To preserve genomic integrity, RAD51 forms a filament on the 3' end of a DSB and on a single-stranded DNA (ssDNA) gap. But unregulated HR results in undesirable chromosomal rearrangements. This review describes the multiple mechanisms that regulate HR with a focus on those mechanisms that promote and contain RAD51 filaments to limit chromosomal rearrangements. If any of these pathways break down and HR becomes unregulated then disease, primarily cancer, can result.

New and Novel Therapies for Gynecologic Cancers

OBJECTIVE

To review recent therapies approved by the US Food and Drug Administration for the treatment of gynecologic malignancies.

DATA SOURCES

PubMed, FDA.gov, ASCO.org.

CONCLUSION

The landscape for treating gynecologic malignancies is rapidly changing. Maintenance therapy now exists for women with advanced ovarian cancer after completing chemotherapy for both newly diagnosed and platinum-sensitive recurrent ovarian cancer. Anti-angiogenic therapy has many applications in gynecologic malignancies. Immunotherapy can be used in certain situations for women with gynecologic malignancies.

IMPLICATIONS FOR NURSING PRACTICE

Biologic agents and immunotherapy have distinct side-effect profiles that nurses need to be aware of to optimize patient care and outcomes.