Major clinical research advances in gynecologic cancer in 2022: highlight on late-line PARP inhibitor withdrawal in ovarian cancer, the impact of ARIEL-4, and SOLO-3

In the 2022 series, we summarized the major clinical research advances in gynecologic oncology based on communications at the conference of Asian Society of Gynecologic Oncology Review Course. The review consisted of 1) Ovarian cancer: long-term follow-up data, new poly (ADP-ribose) polymerase (PARP) inhibitors, overall survival (OS) issues with PARP inhibitor monotherapy, hyperthermic intraperitoneal chemotherapy, immunotherapy, and antibody-drug conjugate; 2) Cervical cancer: surgery in early stage disease, therapy for locally advanced stage and advanced, metastatic, or recurrent setting; and 3) Corpus cancer: follow-up regimen, immune checkpoint inhibitor, WEE1 inhibitor, selective inhibitor of nuclear export. A special note was made on the withdrawal of PARP inhibitor from the market for heavily pretreated ovarian cancer patients based on the final OS results of ARIEL-4 and SOLO-3 due to concerns of increased risk of death.

Pan-Asian adapted ESMO Clinical Practice Guidelines for the diagnosis, treatment and follow-up of patients with endometrial cancer

The most recent version of the European Society for Medical Oncology (ESMO) Clinical Practice Guidelines for the diagnosis, treatment and follow-up of patients with endometrial cancer was published in 2022. It was therefore decided, by both the ESMO and the Indian Society of Medical and Paediatric Oncology (ISMPO), to convene a virtual meeting in July 2022 to adapt the ESMO 2022 guidelines to take into account the variations in the management of endometrial cancer in Asia. These guidelines represent the consensus opinion of a panel of Asian experts representing the oncological societies of China (CSCO), India (ISMPO), Indonesia (ISHMO), Japan (JSMO), Korea (KSMO), Malaysia (MOS), the Philippines (PSMO), Singapore (SSO), Taiwan (TOS) and Thailand (TSCO). Voting was based on scientific evidence and was conducted independently of the current treatment practices and treatment access constraints in the different Asian countries, which were discussed when appropriate. The aim of this guideline manuscript is to provide guidance for the optimisation and harmonisation of the management of patients with endometrial cancer across the different regions of Asia, drawing on the evidence provided by Western and Asian trials whilst respecting the variations in clinical presentation, diagnostic practices including molecular profiling and disparities in access to therapeutic options, including drug approvals and reimbursement strategies.

Current Evidence-Based Systemic Therapy for Advanced and Recurrent Endometrial Cancer

Endometrial cancer (EC) is the most common gynecologic malignancy, with worldwide increasing incidence and disease-associated mortality. Although most patients with EC are diagnosed with early-stage disease, systemic treatment options for patients with advanced or recurrent EC have historically been limited. EC-focused clinical trials and the ensuing therapeutic landscape have expanded since The Cancer Genome Atlas (TCGA) identified 4 distinct EC subgroups associated with differential survival. This endeavor revolutionized our understanding of the genomic characterization of EC as well as molecular drivers of this heterogeneous malignancy, leading to precision oncology approaches to therapeutics and advancement in treatment options. This review describes the current status of and recent advancements in therapeutic options for patients with advanced and recurrent EC. The NCCN Guidelines for Uterine Neoplasms provide detailed recommendations regarding the diagnosis, workup, and management of EC.

Upregulation of NDUFAF2 in Lung Adenocarcinoma Is a Novel Independent Prognostic Biomarker

Background

NADH dehydrogenase (ubiquinone) 1 alpha subcomplex assembly factor 2 (NDUFAF2) acts as a molecular chaperone for the assembly of complex I on the mitochondrial membrane, which is involved in the transfer of electrons in the respiratory chain. However, whether NDUFAF2 plays a role in lung adenocarcinoma (LUAD) is largely unexplored.

Methods

Expression profiles were obtained from the TCGA and GEO databases and integrated via R3.6.3 and several bioinformatics platforms. Western blotting analysis and immunohistochemistry staining were used to examine the expressions of NDUFAF2 in clinical samples. Moreover, the diagnostic and prognostic value of NDUFAF2 expression level was also assessed. GO, KEGG, and gene set enrichment analysis (GSEA) were adopted to investigate NDUFAF2-related molecular functions, signaling pathways, and life activity processes.

Results

NDUFAF2 was predominantly expressed in LUAD, and it is identified as a promising biomarker in the diagnosis of LUAD and its prognostic prediction. Overexpression of NDUFAF2 was correlated with N stage, T stage, and pathologic stage in LUAD, leading to worse overall survival (OS). Besides, the level of NDUFAF2 was independently associated with OS through a multivariate Cox analysis (HR = 1.538, 95% (1.086-2.177), P = 0.015). GO analysis revealed enrichment in innate immune response in mucosa and mucosal immune response, and GSEA indicated enrichment in G2_M_checkpoints, DNA replication, diseases of mitotic cell cycle, retinoblastoma gene in cancer, cell cycle pathway, and cell cycle. Furthermore, the expression level of NDUFAF2 was negatively correlated with infiltration levels of Tem, Tcm, NK CD56^bright cells, and B cells. In contrast, the expression level of NDUFAF2 was positively correlated with the infiltration level of DCs and Th2 cells in LUAD patients.

Conclusions

Collectively, NDUFAF2 is a promising independent prognostic biomarker and target in LUAD. In addition, NDUFAF2 might affect the prognosis of LUAD via DNA replication, diseases of mitotic cell cycle, cell cycle pathway, and cell cycle.

ODF2L acts as a synthetic lethal partner with WEE1 inhibition in epithelial ovarian cancer models

WEE1 has emerged as an attractive target in epithelial ovarian cancer (EOC), but how EOC cells may alter their sensitivity to WEE1 inhibition remains unclear. Here, through a cell cycle machinery-related gene RNAi screen, we found that targeting outer dense fiber of sperm tails 2-like (ODF2L) was a synthetic lethal partner with WEE1 kinase inhibition in EOC cells. Knockdown of ODF2L robustly sensitized cells to treatment with the WEE1 inhibitor AZD1775 in EOC cell lines in vitro as well as in xenografts in vivo. Mechanistically, the increased sensitivity to WEE1 inhibition upon ODF2L loss was accompanied by accumulated DNA damage. ODF2L licensed the recruitment of PKMYT1, a functionally redundant kinase of WEE1, to the CDK1-cyclin B complex and thus restricted the activity of CDK1 when WEE1 was inhibited. Clinically, upregulation of ODF2L correlated with CDK1 activity, DNA damage levels, and sensitivity to WEE1 inhibition in patient-derived EOC cells. Moreover, ODF2L levels predicted the response to WEE1 inhibition in an EOC patient-derived xenograft model. Combination treatment with tumor-targeted lipid nanoparticles that packaged ODF2L siRNA and AZD1775 led to the synergistic attenuation of tumor growth in the ID8 ovarian cancer syngeneic mouse model. These data suggest that WEE1 inhibition is a promising precision therapeutic strategy for EOC cells expressing low levels of ODF2L.

Design, synthesis and evaluation of N3-substituted quinazolinone derivatives as potential Bloom's Syndrome protein (BLM) helicase inhibitor for sensitization treatment of colorectal cancer

The homologous recombination repair (HRR) pathway is critical for repairing double-strand breaks (DSB). Inhibition of the HRR pathway is usually considered a promising strategy for anticancer therapy. The Bloom's Syndrome Protein (BLM), a DNA helicase, is essential for promoting the HRR pathway. Previously, we discovered quinazolinone derivative 9h as a potential BLM inhibitor, which suppressed the proliferation of colorectal cancer (CRC) cell HCT116. Herein, a new series of quinazolinone derivatives with N3-substitution was designed and synthesized to improve the anticancer activity and explore the structure-activity relationship (SAR). After evaluating their BLM inhibitory activity, the SAR was discussed, leading to identifying compound 21 as a promising BLM inhibitor. 21 exhibited the potent BLM-dependent cytotoxicity against the CRC cells but weak against normal cells. Further evaluation revealed that 21 could disrupt the HRR level while inhibiting BLM located on the DSB site and trigger DNA damage in the CRC cells. This compound effectively suppressed the proliferation and invasion of CRC cells, along with cell cycle arrest and apoptosis. Consequently, 21 might be a promising candidate for treating CRC, and the BLM might be a new potential therapeutic target for CRC.

Drugs Targeting p53 Mutations with FDA Approval and in Clinical Trials

Mutations in the tumor suppressor p53 (p53) promote cancer progression. This is mainly due to loss of function (LOS) as a tumor suppressor, dominant-negative (DN) activities of missense mutant p53 (mutp53) over wild-type p53 (wtp53), and wtp53-independent oncogenic activities of missense mutp53 by interacting with other tumor suppressors or oncogenes (gain of function: GOF). Since p53 mutations occur in ~50% of human cancers and rarely occur in normal tissues, p53 mutations are cancer-specific and ideal therapeutic targets. Approaches to target p53 mutations include (1) restoration or stabilization of wtp53 conformation from missense mutp53, (2) rescue of p53 nonsense mutations, (3) depletion or degradation of mutp53 proteins, and (4) induction of p53 synthetic lethality or targeting of vulnerabilities imposed by p53 mutations (enhanced YAP/TAZ activities) or deletions (hyperactivated retrotransposons). This review article focuses on clinically available FDA-approved drugs and drugs in clinical trials that target p53 mutations and summarizes their mechanisms of action and activities to suppress cancer progression.

Targeting replication stress in cancer therapy

Replication stress is a major cause of genomic instability and a crucial vulnerability of cancer cells. This vulnerability can be therapeutically targeted by inhibiting kinases that coordinate the DNA damage response with cell cycle control, including ATR, CHK1, WEE1 and MYT1 checkpoint kinases. In addition, inhibiting the DNA damage response releases DNA fragments into the cytoplasm, eliciting an innate immune response. Therefore, several ATR, CHK1, WEE1 and MYT1 inhibitors are undergoing clinical evaluation as monotherapies or in combination with chemotherapy, poly[ADP-ribose]polymerase (PARP) inhibitors, or immune checkpoint inhibitors to capitalize on high replication stress, overcome therapeutic resistance and promote effective antitumour immunity. Here, we review current and emerging approaches for targeting replication stress in cancer, from preclinical and biomarker development to clinical trial evaluation.

Recent progress in the use of pharmacotherapy for endometrial cancer

INTRODUCTION

Endometrial cancer (EC) is the most common gynecological cancer in developed countries. The ESGO/ESTRO/ESP updated evidence-based guidelines in 2020, introducing molecular classification to guide EC treatment. The genomic-based approach has identified four prognostic subgroups of EC. Each of these may benefit from a tailored treatment depending on the molecular profile, the histotype, and stage of disease for the adjuvant and the metastatic/recurrent setting. Several clinical trials are now ongoing to identify the best treatment according to the molecular profile of EC.

AREAS COVERED

This review analyzes tailored treatment for EC according to the molecular profile, both in the adjuvant and in the metastatic/recurrent setting. The authors review the results of clinical studies and highlight ongoing trials.

EXPERT OPINION

Several new agents are under evaluation in order to personalize EC treatment according to specific molecular profiles in the adjuvant, advanced, and recurrent settings. Clinical trials investigating the impact of molecular classification have yielded encouraging results. EC can no longer be considered a single tumor entity susceptible to a single treatment modality but rather be split into four distinct types, requiring tailored treatments.

Targeted Therapies in the Treatment of Uterine Serous Carcinoma

OPINION STATEMENT

Despite the dismal prognosis of uterine serous carcinoma (USC), recent advances in molecular classification and targeted treatments have demonstrated improvements in survival outcomes for patients both in the upfront and recurrent treatment settings. After appropriate surgical staging and surgical cytoreduction as indicated, correct pathologic and molecular classification of USC is important to provide the most appropriate systemic adjuvant treatment. HER2-targeted agents are one of the most important advances in the treatment of USC in decades. Thus, for HER2-positive tumors, the addition of trastuzumab to conventional chemotherapy is indicated in those with advanced stage and/or recurrent disease. Treatment with pembrolizumab and lenvatinib suggests a 50% response rate in women with recurrent disease which serves as a promising targeted treatment strategy. Overall, emerging targeted therapeutic options with antibody-drug conjugates (i.e. targeting HER2, folic acid receptor alpha, or Trop-2), combinations of immunotherapies and tyrosine kinase inhibitors, PARP inhibitors, WEE1 inhibitors, and AKT inhibitors shed further promise in advancements of effective disease-modifying treatments for this unmet medical need for patients with USC. Several trials evaluating these targeted agents are ongoing, and those results are eagerly awaited. As such, enrollment of patients in clinical trials is highly recommended as it will provide patients with a higher level of personalized cancer care.

Looking beyond carboplatin and paclitaxel for the treatment of advanced/recurrent endometrial cancer

Endometrial cancer incidence and mortality are rising among all ethnic groups. Carboplatin plus paclitaxel is the established frontline treatment for advanced/recurrent disease; however, subsequent treatment with traditional cytotoxic chemotherapy is challenging. The molecular characterization of endometrial cancer has provided important insights into the biological drivers of carcinogenesis, which has allowed for the development of newer precision immunotherapies and targeted therapies, including pembrolizumab, dostarlimab, and lenvatinib. Until recently, platinum rechallenge was often considered at the time of recurrence, given the lack of other available therapeutic options; however, "platinum sensitivity" in endometrial cancer is subjective and largely based on expert opinion and/or practitioner experience. Small retrospective studies have tried to provide guidance on the utility of platinum rechallenge, but they are limited by variable patient characteristics and small sample sizes. The applicability of these retrospective studies to contemporary clinical practice is difficult in the setting of changing patient demographics, a better understanding of endometrial cancer drivers, and the recent approvals of immune checkpoint inhibitors and the combination of lenvatinib plus pembrolizumab in the second-line setting. The primary focus of this review is to distill the available data regarding platinum-doublet chemotherapy rechallenge and highlight recent pivotal developments in endometrial cancer treatment, as well as future directions.

PD0166285 sensitizes esophageal squamous cell carcinoma to radiotherapy by dual inhibition of WEE1 and PKMYT1

Background

Esophageal squamous cell carcinoma (ESCC) is an aggressive tumor with a 5-year survival rate of only 20%. More than 80% of ESCC patients possess TP53 mutation, which abolishes the G1/S checkpoint and accelerates the cell cycle. Thus, WEE1 and PKMYT1, regulators of G2/M phase in cell cycle, play essential roles in TP53-mutated cancer cells. PD0166285(PD) is a pyridopyrimidine compound that can inhibit WEE1 and PKMYT1 simultaneously, however, the effects of PD on ESCC, either as monotherapy or in combination therapy with radiotherapy, remain unclear.

Methods

To measure the anti-tumor efficacy of PD in ESCC cells, cell viability, cell cycle and cell apoptosis assays were examined in KYSE150 and TE1 cells with PD treatment. The combination therapy of PD and irradiation was also performed in ESCC cells to find whether PD can sensitize ESCC cells to irradiation. Vivo assays were also performed to investigate the efficacy of PD.

Results

We found that the IC50 values of PD among ESCC cells ranged from 234 to 694 nM, PD can regulate cell cycle and induce cell apoptosis in ESCC cells in a dose-dependent manner. When combined with irradiation, PD sensitized ESCC cells to irradiation by abolishing G2/M phase arrest, inducing a high ratio of mitosis catastrophe, eventually leading to cell death. We also demonstrated that PD can attenuate DNA damage repair by inhibiting Rad51, further research also found the interaction of WEE1 and Rad51. In vivo assays, PD inhibited the tumor growth in mice, combination therapy showed better therapeutic efficacy.

Conclusion

PD0166285 can exert antitumor effect by inhibiting the function of WEE1 and PKMYT1 in ESCC cells, and also sensitize ESCC cells to irradiation not only by abolishing G2/M arrest but also attenuating DNA repair directly. We believe PD0166285 can be a potent treatment option for ESCC in the future.

Exploring the genetic space of the DNA damage response for cancer therapy through CRISPR-based screens

The concepts of synthetic lethality and viability have emerged as powerful approaches to identify vulnerabilities and resistances within the DNA damage response for the treatment of cancer. Historically, interactions between two genes have had a longstanding presence in genetics and have been identified through forward genetic screens that rely on the molecular basis of the characterized phenotypes, typically caused by mutations in single genes. While such complex genetic interactions between genes have been studied extensively in model organisms, they have only recently been prioritized as therapeutic strategies due to technological advancements in genetic screens. Here, we discuss synthetic lethal and viable interactions within the DNA damage response and present how CRISPR-based genetic screens and chemical compounds have allowed for the systematic identification and targeting of such interactions for the treatment of cancer.

Advances in Chemotherapy and Targeted Therapies in Endometrial Cancer

Endometrial cancer is now recognized to be several diseases with differing biology and responses to treatment. Improved molecular characterization has furthered the development and testing of targeted therapies in the different cohorts of endometrial cancer. Lessons are being learned from other cancers that share similar molecular typing, and hence, potentially similar tumor behavior. This commentary serves as a broad overview of the types of advances to which our patients now have access.

Identification of a Molecularly-Defined Subset of Breast and Ovarian Cancer Models that Respond to WEE1 or ATR Inhibition, Overcoming PARP Inhibitor Resistance

PURPOSE

PARP inhibitors (PARPi) induce synthetic lethality in homologous recombination repair (HRR)-deficient tumors and are used to treat breast, ovarian, pancreatic, and prostate cancers. Multiple PARPi resistance mechanisms exist, most resulting in restoration of HRR and protection of stalled replication forks. ATR inhibition was highlighted as a unique approach to reverse both aspects of resistance. Recently, however, a PARPi/WEE1 inhibitor (WEE1i) combination demonstrated enhanced antitumor activity associated with the induction of replication stress, suggesting another approach to tackling PARPi resistance.

EXPERIMENTAL DESIGN

We analyzed breast and ovarian patient-derived xenoimplant models resistant to PARPi to quantify WEE1i and ATR inhibitor (ATRi) responses as single agents and in combination with PARPi. Biomarker analysis was conducted at the genetic and protein level. Metabolite analysis by mass spectrometry and nucleoside rescue experiments ex vivo were also conducted in patient-derived models.

RESULTS

Although WEE1i response was linked to markers of replication stress, including STK11/RB1 and phospho-RPA, ATRi response associated with ATM mutation. When combined with olaparib, WEE1i could be differentiated from the ATRi/olaparib combination, providing distinct therapeutic strategies to overcome PARPi resistance by targeting the replication stress response. Mechanistically, WEE1i sensitivity was associated with shortage of the dNTP pool and a concomitant increase in replication stress.

CONCLUSIONS

Targeting the replication stress response is a valid therapeutic option to overcome PARPi resistance including tumors without an underlying HRR deficiency. These preclinical insights are now being tested in several clinical trials where the PARPi is administered with either the WEE1i or the ATRi.

Looking Under the Lamppost: The Search for New Cancer Targets in the Human Kinome

The number of cancer drugs is increasing as new chemical entities are developed to target molecules, often protein kinases, driving cancer progression. In 2009, Fedorov et al. identified that of the protein kinases in the human kinome, most of the focus has been on a small subset. They highlighted that many poorly investigated protein kinases were cancer drivers, but there was no relationship between publications and involvement in cancer development or progression. Since 2009, there has been a doubling in the number of publications, patents, and drugs targeting the kinome. To determine whether this was an expansion in knowledge of well-studied targets-searching in the light under the lamppost-or an explosion of investigations into previously poorly investigated targets, we searched the literature for publications on each kinase, updating Federov et al.'s assessment of the druggable kinome. The proportion of papers focusing on the 50 most-studied kinases had not changed, and the makeup of those 50 had barely changed. The majority of new drugs (80%) were against the same group of 50 kinases identified as targets 10 years ago, and the proportion of studies investigating previously poorly investigated kinases (<1%) was unchanged. With three exceptions [p38 mitogenactivated protein kinase (p38a), AMP-activated protein kinase catalytic α-subunit 1,2, and B-Raf proto-oncogene (BRAF) serine/threonine kinase], >95% of publications addressing kinases still focused on a relatively small proportion (<50%) of the human kinome independently of their involvement as cancer drivers. There is, therefore, still extensive scope for discovery of therapeutics targeting different protein kinases in cancer and still a bias toward well-characterized targets over the innovative searchlight into the unknown. SIGNIFICANCE STATEMENT: This study presents evidence that drug discovery efforts in cancer are still to some extent focused on a narrow group of well-studied kinases 10 years after the identification of multiple novel cancer targets in the human kinome. This suggests that there is still room for researchers in academia, industry, and the not-for-profit sector to develop new and diverse therapies targeting kinases for cancer.

Targeting the DNA damage response beyond poly(ADP-ribose) polymerase inhibitors: novel agents and rational combinations

PURPOSE OF REVIEW

Poly(ADP-ribose) polymerase (PARP) inhibitors have transformed treatment paradigms in multiple cancer types defined by homologous recombination deficiency (HRD) and have become the archetypal example of synthetic lethal targeting within the DNA damage response (DDR). Despite this success, primary and acquired resistance to PARP inhibition inevitability threaten the efficacy and durability of response to these drugs. Beyond PARP inhibitors, recent advances in large-scale functional genomic screens have led to the identification of a steadily growing list of genetic dependencies across the DDR landscape. This has led to a wide array of novel synthetic lethal targets and corresponding inhibitors, which hold promise to widen the application of DDR inhibitors beyond HRD and potentially address PARP inhibitor resistance.

RECENT FINDINGS

In this review, we describe key synthetic lethal interactions that have been identified across the DDR landscape, summarize the early phase clinical development of the most promising DDR inhibitors, and highlight relevant combinations of DDR inhibitors with chemotherapy and other novel cancer therapies, which are anticipated to make an impact in rationally selected patient populations.

SUMMARY

The DDR landscape holds multiple opportunities for synthetic lethal targeting with multiple novel DDR inhibitors being evaluated on early phase clinical trials. Key challenges remain in optimizing the therapeutic window of ATR and WEE1 inhibitors as monotherapy and in combination approaches.

Novel approaches for treatment of endometrial carcinoma

Endometrial cancer (EC) is common malignancy in women and its incidence is slowly on the rise. Accurate surgical staging, with aggressive cytoreduction when indicated, remains the most critical step in the treatment. Careful pathological evaluation and/or molecular risk stratification guides for proper systemic adjuvant radiotherapy ± chemotherapy. Recurrent and metastatic EC has dismal prognosis and palliative therapies (chemotherapy, hormonal therapy or radiation) forms the backbone of treatment. There is an unmet need of newer therapies to improve survival in such cases. A number of tyrosine kinase inhibitors are currently under evaluation. Recent data on therapeutic targeting of HER2 positive serous EC is exciting. Data on check point inhibitors particularly based on biomarker select population has raised hope for potentially effective treatment for women with high risk endometrial cancer .

p53 as a biomarker and potential target in gastrointestinal stromal tumors

KIT and PDGFRA play a major role in the oncogenic process in gastrointestinal stroma tumors (GIST) and small molecules have been employed with great success to target the KIT and PDGFRA pathways in this cancer. However, approximately 10% of patients with GIST are resistant to current targeted drug therapy. There is a need to explore other potential targets. Although p53 alterations frequently occur in most cancers, studies regarding p53 in GIST have been limited. The CDKN2A/MDM2/p53 axis regulates cell cycle progression and DNA damage responses, which in turn control tumor growth. This axis is the major event required for transformation from low- to high-risk GIST. Generally, p53 mutation is infrequent in GIST, but p53 overexpression has been reported to be associated with high-risk GIST and unfavorable prognosis, implying that p53 should play a critical role in GIST. Also, Wee1 regulates the cell cycle and the antitumor activity of Wee1 inhibition was reported to be p53 mutant dependent. In addition, Wee1 was reported to have potential activity in GIST through the regulation of KIT protein and this mechanism may be dependent on p53 status. In this article, we review previous reports regarding the role of p53 in GIST and propose targeting the p53 pathway as a novel additional treatment strategy for GIST.

DNA Damage Response Inhibitors in Cholangiocarcinoma: Current Progress and Perspectives

Cholangiocarcinoma (CCA) is a poorly treatable type of cancer and its incidence is dramatically increasing. The lack of understanding of the biology of this tumor has slowed down the identification of novel targets and the development of effective treatments. Based on next generation sequencing profiling, alterations in DNA damage response (DDR)-related genes are paving the way for DDR-targeting strategies in CCA. Based on the notion of synthetic lethality, several DDR-inhibitors (DDRi) have been developed with the aim of accumulating enough DNA damage to induce cell death in tumor cells. Observing that DDRi alone could be insufficient for clinical use in CCA patients, the combination of DNA-damaging regimens with targeted approaches has started to be considered, as evidenced by many emerging clinical trials. Hence, novel therapeutic strategies combining DDRi with patient-specific targeted drugs could be the next level for treating cholangiocarcinoma.

Uterine carcinosarcoma associated with a germline nibrin (NBN) mutation

•

We report a patient with uterine carcinosarcoma associated with a germline NBN mutation.

•

Tumor also exhibited a high tumor mutational burden (>10 mutations/Mb)

•

Patient responded to platinum rechallenge, PARP inhibitor maintenance and immunotherapy.

•

Patient remains in alive and with disease control for > 4 years after diagnosis.

We report a 62-year-old patient with uterine carcinosarcoma associated with a germline mutation in the NBN gene which is involved in the homologous recombination repair (HRR) pathway. This patient responded well to several different treatment strategies including platinum-based chemotherapy twice, PARP inhibitor therapy and immunotherapy, and is currently alive and with disease control, more than four years after diagnosis. This case is the first report of uterine carcinosarcoma associated with a germline mutation in NBN and highlights how specific genomic alterations may guide treatment decisions that may alter the natural history of an otherwise devastating disease.

Ricolinostat enhances adavosertib‑induced mitotic catastrophe in TP53‑mutated head and neck squamous cell carcinoma cells

TP53 mutation is one of the most frequent gene mutations in head and neck squamous cell carcinoma (HNSCC) and could be a potential therapeutic target. Recently, the WEE1 G2 checkpoint kinase (WEE1) inhibitor adavosertib (Adv) has attracted attention because of its selective cytotoxicity against TP53-mutated cells and has shown promising activity in early phase clinical trials. In the present study, it was demonstrated that combined treatment with Adv and a selective histone deacetylase 6 (HDAC6) inhibitor, ricolinostat (RCS), synergistically enhanced cell death induction in four out of five HNSCC cell lines with TP53 mutation (CAL27, SAS, HSC-3, and OSC-19), one HNSCC cell line with impaired TP53 function by HPV-infection (UPCI-SCC154), and TP53-knockout human lung cancer cell line (A549 TP53-KO), but not in TP53 wild-type A549 cells. Time-lapse imaging showed that RCS enhanced the Adv-induced mitotic catastrophe. Consistent with this, RCS treatment suppressed checkpoint kinase 1 (Chk1) (Ser345) phosphorylation and co-administration of RCS with Adv suppressed cyclin-dependent kinase 1 (Tyr15) phosphorylation along with increased expression of γ-H2A.X, a marker of DNA double-strand breaks in CAL27 cells. These data showed that RCS enhanced Adv-induced premature mitotic entry and cell death induction in the mitotic phase. However, although HDAC6 knockdown enhanced Adv-induced cell death with γ-H2A.X elevation, HDAC6 knockdown did not repress Chk1 phosphorylation in CAL27 cells. Our data demonstrated that the co-administration of RCS with Adv in HNSCC cells resulted in the suppression of Chk1 activity, leading to synergistically enhanced apoptosis via mitotic catastrophe in a p53-dependent manner. This enhanced cell death appeared to be partially mediated by the inhibition of HDAC6 activity by RCS.

WEE1 kinase is a therapeutic vulnerability in CIC-DUX4 undifferentiated sarcoma

CIC-DUX4 rearrangements define an aggressive and chemotherapy-insensitive subset of undifferentiated sarcomas. The CIC-DUX4 fusion drives oncogenesis through direct transcriptional upregulation of cell cycle and DNA replication genes. Notably, CIC-DUX4–mediated CCNE1 upregulation compromises the G₁/S transition to confer a dependence on the G₂/M cell cycle checkpoint. Through an integrative transcriptional and kinase activity screen using patient-derived specimens, we now show that CIC-DUX4 sarcomas depend on the G₂/M checkpoint regulator WEE1 as part of an adaptive survival mechanism. Specifically, CIC-DUX4 sarcomas depended on WEE1 activity to limit DNA damage and unscheduled mitotic entry. Consequently, genetic or pharmacologic WEE1 inhibition in vitro and in vivo led to rapid DNA damage–associated apoptotic induction of patient-derived CIC-DUX4 sarcomas. Thus, we identified WEE1 as a vulnerability targetable by therapeutic intervention in CIC-DUX4 sarcomas.

Everything Comes with a Price: The Toxicity Profile of DNA-Damage Response Targeting Agents

Simple Summary

DNA damage induces genome instability, which may elicit cancer development. Defects in the DNA repair machinery further enhance cancer predisposition, but can also be exploited as a therapeutic target. Indeed, targeted agents against specific components of DNA repair, such as PARP inhibitors, are employed in various tumor types, while others, such as ATR, CHK1 or WEE1 inhibitors, are in clinical development. Even though these molecules have proven to be effective in different settings, they display several on- and off-target toxicities, shared by the whole pharmacological class or are drug specific. Among these effects, hematological and gastrointestinal toxicities are the most common, while others are less frequent but potentially life-threatening (e.g., myelodysplastic syndromes). Particular caution is needed in the case of combinatorial therapeutic approaches, which are currently being developed in clinical trials. In any case, it is necessary to recognize and properly manage adverse events of these drugs. This review provides a comprehensive overview on the safety profile of DDR-targeting agents, including indications for their management in clinical practice.

Abstract

Targeting the inherent vulnerability of cancer cells with an impaired DNA Damage Repair (DDR) machinery, Poly-ADP-Ribose-Polymerase (PARP) inhibitors have yielded significant results in several tumor types, eventually entering clinical practice for the treatment of ovarian, breast, pancreatic and prostate cancer. More recently, inhibitors of other key components of DNA repair, such as ATR, CHK1 and WEE1, have been developed and are currently under investigation in clinical trials. The inhibition of DDR inevitably induces on-target and off-target adverse events. Hematological and gastrointestinal toxicities as well as fatigue are common with all DDR-targeting agents, while other adverse events are drug specific, such as hypertension with niraparib and transaminase elevation with rucaparib. Cases of pneumonitis and secondary hematological malignancies have been reported with PARP inhibitors and, despite being overly rare, they deserve particular attention due to their severity. Safety also represents a crucial issue for the development of combination regimens incorporating DDR-targeting agents with other treatments, such as chemotherapy, anti-angiogenics or immunotherapy. As such, overlapping and cumulative toxicities should be considered, especially when more than two classes of drugs are combined. Here, we review the safety profile of DDR-targeting agents when used as single agents or in combination and we provide principles of toxicity management.

Therapeutic Targeting of DNA Damage Response in Cancer

DNA damage response (DDR) is critical to ensure genome stability, and defects in this signaling pathway are highly associated with carcinogenesis and tumor progression. Nevertheless, this also provides therapeutic opportunities, as cells with defective DDR signaling are directed to rely on compensatory survival pathways, and these vulnerabilities have been exploited for anticancer treatments. Following the impressive success of PARP inhibitors in the treatment of BRCA-mutated breast and ovarian cancers, extensive research has been conducted toward the development of pharmacologic inhibitors of the key components of the DDR signaling pathway. In this review, we discuss the key elements of the DDR pathway and how these molecular components may serve as anticancer treatment targets. We also summarize the recent promising developments in the field of DDR pathway inhibitors, focusing on novel agents beyond PARP inhibitors. Furthermore, we discuss biomarker studies to identify target patients expected to derive maximal clinical benefits as well as combination strategies with other classes of anticancer agents to synergize and optimize the clinical benefits.

WEE1 kinase protects the stability of stalled DNA replication forks by limiting CDK2 activity

Cellular feedback systems ensure genome maintenance during DNA replication. When replication forks stall, newly replicated DNA is protected by pathways that limit excessive DNA nuclease attacks. Here we show that WEE1 activity guards against nascent DNA degradation at stalled forks. Furthermore, we identify WEE1-dependent suppression of cyclin-dependent kinase 2 (CDK2) as a major activity counteracting fork degradation. We establish DNA2 as the nuclease responsible for excessive fork degradation in WEE1-inhibited cells. In addition, WEE1 appears to be unique among CDK activity suppressors in S phase because neither CHK1 nor p21 promote fork protection as WEE1 does. Our results identify a key role of WEE1 in protecting stalled forks, which is separate from its established role in safeguarding DNA replication initiation. Our findings highlight how WEE1 inhibition evokes massive genome challenges during DNA replication, and this knowledge may improve therapeutic strategies to specifically eradicate cancer cells that frequently harbor elevated DNA replication stress.

Cell cycle on the crossroad of tumorigenesis and cancer therapy

Aberrancy in cell cycle progression is one of the fundamental mechanisms underlying tumorigenesis, making regulators of the cell cycle machinery rational anticancer therapeutic targets. A growing body of evidence indicates that the cell cycle regulatory pathway integrates into other hallmarks of cancer, including metabolism remodeling and immune escape. Thus, therapies against cell cycle machinery components can not only repress the division of cancer cells, but also reverse cancer metabolism and restore cancer immune surveillance. Besides the ongoing effects on the development of small molecule inhibitors (SMIs) of the cell cycle machinery, proteolysis targeting chimeras (PROTACs) have recently been used to target these oncogenic proteins related to cell cycle progression. Here, we discuss the rationale of cell cycle targeting therapies, particularly PROTACs, to more efficiently retard tumorigenesis.

Endometrial cancer: molecular classification and future treatments

The treatment for endometrial cancer is rapidly evolving with the development of molecular analysis and novel strategies. Surgical resection, cytotoxic chemotherapy, endocrine or hormonal treatment, and radiation have been the staples of treatment for decades. However, precision based approaches for tumours are rapidly becoming a part of these strategies. Biomarker driven treatments are now a part of primary and recurrent treatment algorithms. This review aims to describe the current state of molecular analysis and treatment for endometrial cancer as well as to elucidate potential approaches for the near future.

Activation of oxidative phosphorylation in TP53-inactive endometrial carcinomas with a poor prognosis

OBJECTIVE

We aimed to identify pathways for potential therapeutic targets by conducting molecular profiling of endometrial carcinomas in patients with poor prognosis.

METHODS

The classification of endometrial carcinomas has undergone a paradigm shift with the advent of next generation sequencing based molecular profiling. Although this emerging classification reflects poor prognosis in patients with endometrial carcinoma, knowledge of affected biological pathways is still lacking. In this study, 85 patients with endometrial carcinomas at the Shizuoka Cancer Center were evaluated from January 2014 to March 2019 and classified based on The Cancer Genome Atlas subgroups. The accumulation of germline and somatic mutations was determined using next generation sequencing. Gene expression profiling was used to determine the effect of TP53 inactivation on the recurrence of endometrial carcinoma. Additionally, the biological pathways associated with TP53 inactivation were estimated by pathway analysis based on gene expression.

RESULTS

Based on The Cancer Genome Atlas classification, the ratio of polymerase-epsilon to copy number-high subgroups and the frequency of PTEN and TP53 mutations differed in patients, and mutations of ARHGAP35 observed in normal endometrium were accumulated in the polymerase-epsilon and microsatellite instability subgroups. We revealed that copy number-high reflects TP53 inactivation in endometrial carcinomas, and that TP53-inactive tumors with or without TP53 mutations have poor prognosis. Furthermore, overexpression of aurora kinase A and activation of oxidative phosphorylation were found in TP53-inactivated endometrial carcinomas, suggesting that the PI3K/mTOR and autophagy pathways are potential drug targets.

CONCLUSION

Our analysis revealed a relationship between pathways involved in oxidative phosphorylation and poor prognosis and provides insight into potential drug targets.

ADAGIO: a phase IIb international study of the Wee1 inhibitor adavosertib in women with recurrent or persistent uterine serous carcinoma

BACKGROUND

Uterine serous carcinoma is a distinct histologic subtype of endometrial cancer with an aggressive phenotype, poor prognosis, and limited therapeutic options. A previous proof-of-concept phase II trial of the Wee1 inhibitor adavosertib in uterine serous carcinoma demonstrated evidence of durable clinical activity.

PRIMARY OBJECTIVE

To evaluate the efficacy of adavosertib in women with recurrent or persistent uterine serous carcinoma.

STUDY HYPOTHESIS

We hypothesize that adavosertib will demonstrate significant clinical activity, as measured by objective response rate, in women with recurrent or persistent uterine serous carcinoma.

TRIAL DESIGN

Eligible participants will receive adavosertib monotherapy until disease progression or unacceptable toxicity, starting at the recommended phase II dosing of adavosertib 300 mg daily days 1 through 5 and 8 through 12 of a 21-day cycle. Participants will have restaging studies every 6 weeks for the first 48 weeks and then every 9 weeks thereafter.

MAJOR INCLUSION/EXCLUSION CRITERIA

Patients with histologically confirmed recurrent or persistent uterine serous carcinoma, including endometrial carcinoma of mixed histology where the serous component comprises at least 10% of the tumor, and who have received at least one prior platinum-based chemotherapy regimen for the management of uterine serous carcinoma, are eligible for inclusion in the trial. Participants must have measurable disease by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria. Participants with carcinosarcoma are not eligible.

PRIMARY ENDPOINT

The primary endpoint is the objective response rate by RECIST 1.1 criteria, as determined by blinded independent central review.

SAMPLE SIZE

Approximately 120 patients will be enrolled in this trial.

ESTIMATED DATES FOR COMPLETING AND PRESENTING RESULTS

Study completion and presentation of results are projected to be at the end of 2022.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT04590248.

Development of New Cancer Treatment by Identifying and Focusing the Genetic Mutations or Altered Expression in Gynecologic Cancers

With the advent of next-generation sequencing (NGS), The Cancer Genome Atlas (TCGA) research network has given gynecologic cancers molecular classifications, which impacts clinical practice more and more. New cancer treatments that identify and target pathogenic abnormalities of genes have been in rapid development. The most prominent progress in gynecologic cancers is the clinical efficacy of poly(ADP-ribose) polymerase (PARP) inhibitors, which have shown breakthrough benefits in reducing hazard ratios (HRs) (HRs between 0.2 and 0.4) of progression or death from BRCA1/2 mutated ovarian cancer. Immune checkpoint inhibition is also promising in cancers that harbor mismatch repair deficiency (dMMR)/microsatellite instability (MSI). In this review, we focus on the druggable genetic alterations in gynecologic cancers by summarizing literature findings and completed and ongoing clinical trials.

RNA m6A demethylase FTO-mediated epigenetic up-regulation of LINC00022 promotes tumorigenesis in esophageal squamous cell carcinoma

Background

Long non-coding RNA (LncRNA) controls cell proliferation and plays a significant role in the initiation and progression of esophageal squamous cell carcinoma (ESCC). N6-methyladenosine (m6A) modification now is recognized as a master driver of RNA function to maintain homeostasis in cancer cells. However, how m6A regulates LncRNA function and its role in tumorigenesis of ESCC remain unclear.

Methods

Multiple ESCC datasets were used to analyze gene expression in tumor tissues and normal tissues. Kaplan-Meier method and the ROC curve were conducted to evaluate the prognostic value and diagnostic value of LINC00022 in ESCC, respectively. Both gain-of-function and loss-of-function experiments were employed to investigate the effects of LINC00022 on ESCC growth in vitro and in vivo. Bioinformatics analysis, colorimetric m6A assay, RIP, MeRIP and co-IP was performed to explore the epigenetic mechanism of LINC00022 up-regulation in ESCC.

Results

Here we report that m6A demethylation of LncRNA LINC00022 by fat mass and obesity-associated protein (FTO) promotes tumor growth of ESCC in vivo. Clinically, we revealed that LINC00022 was up-regulated in primary ESCC samples and was predictive of poor clinical outcome for ESCC patients. Mechanistically, LINC00022 directly binds to p21 protein and promotes its ubiquitination-mediated degradation, thereby facilitating cell-cycle progression and proliferation. Further, the elevated FTO in ESCC decreased m6A methylation of LINC00022 transcript, leading to the inhibition of LINC00022 decay via the m6A reader YTHDF2. Over-expression of FTO was shown to drive LINC00022-dependent cell proliferation and tumor growth of ESCC.

Conclusions

Thus, this study demonstrated m6A-mediated epigenetic modification of LncRNA contributes to the tumorigenesis in ESCC and LINC00022, specific target of m6A, serves as a potential biomarker for this malignancy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02096-1.

Divulging the Critical Role of HuR in Pancreatic Cancer as a Therapeutic Target and a Means to Overcome Chemoresistance

Simple Summary

With pancreatic cancer incidence constantly rising, constituting one of the most lethal type of cancers worldwide, the need for discovering novel therapeutic targets and approaches becomes of the utmost importance. Meanwhile, modern eating habits, hyperadiposity, mutational burden affecting core signaling pathways and the unique tumor microenvironment of pancreatic cancer tissues intermingle and form a disease that is lethal and hard to treat. The importance of HuR in pancreatic cancer has repeatedly been observed and represents a key molecule in pancreatic carcinogenesis and chemoresistance. Therefore, creating and obtaining new therapeutic skills against HuR protein could prove to be the answer to pancreatic cancer therapy.

Abstract

Pancreatic cancer is set to become the most lethal and common type of cancer worldwide. This is partly attributed to the mutational burden that affects core signaling pathways and the crosstalk of tumor cells with their surrounding microenvironment, but it is also due to modern eating habits. Hyperadiposity along with the constant rise in metabolic syndrome’s incidence contribute to a state of metaflammation that impacts immune cells and causes them to shift towards an immunosuppressive phenotype that, ultimately, allows tumor cells to evade immune control. Unfortunately, among the conventional therapeutic modalities and the novel therapeutic agents introduced, pancreatic cancer still holds one of the lowest response rates to therapy. Human antigen R (HuR), an RNA binding protein (RBP), has been repeatedly found to be implicated in pancreatic carcinogenesis and chemotherapy resistance through the posttranscriptional binding and regulation of mRNA target genes. Additionally, its overexpression has been linked to adverse clinical outcomes, in terms of tumor grade, stage, lymph node status and metastasis. These properties suggest the prospective role that HuR’s therapeutic targeting can play in facilitating pancreatic neoplasia and could provide the means to overcome chemoresistance.

The emerging role of molecular pathology in directing the systemic treatment of endometrial cancer

Following the discovery of the four molecular subtypes of endometrial cancer (EC) by The Cancer Genome Atlas (TCGA) in 2013, subsequent studies used surrogate markers to develop and validate a clinically relevant EC classification tool to recapitulate TCGA subtypes. Molecular classification combines focused sequencing (POLE) and immunohistochemistry (mismatch repair and p53 proteins) to assign patients with EC to one of four molecular subtypes: POLEmut, MMRd, p53abn and NSMP (no specific molecular profile). Unlike histopathological evaluation, the molecular subtyping of EC offers an objective and reproducible classification system that has been shown to have prognostic value and therapeutic implications. It is an exciting time in EC care where we have moved beyond treatment based on histomorphology alone, and molecular classification will now finally allow assessment of treatment efficacy within biologically similar tumours. It is now recommended that molecular classification should be considered for all ECs, and should be performed routinely in all high grade tumours. It is also recommended to incorporate molecular classification into standard pathology reporting and treatment decision-making algorithms. In this review, we will discuss how the molecular classification of EC can be used to guide both conventional and targeted therapy in this new molecular era.

Targeting the replication stress response through synthetic lethal strategies in cancer medicine

The replication stress response (RSR) involves a downstream kinase cascade comprising ataxia telangiectasia-mutated (ATM), ATM and rad3-related (ATR), checkpoint kinases 1 and 2 (CHK1/2), and WEE1-like protein kinase (WEE1), which cooperate to arrest the cell cycle, protect stalled forks, and allow time for replication fork repair. In the presence of elevated replicative stress, cancers are increasingly dependent on RSR to maintain genomic integrity. An increasing number of drug candidates targeting key RSR nodes, as monotherapy through synthetic lethality, or through rational combinations with immune checkpoint inhibitors and targeted therapies, are demonstrating promising efficacy in early phase trials. RSR targeting is also showing potential in reversing PARP inhibitor resistance, an important area of unmet clinical need. In this review, we introduce the concept of targeting the RSR, detail the current landscape of monotherapy and combination strategies, and discuss emerging therapeutic approaches, such as targeting Polθ.

Enhanced Efficacy of Aurora Kinase Inhibitors in G2/M Checkpoint Deficient TP53 Mutant Uterine Carcinomas Is Linked to the Summation of LKB1-AKT-p53 Interactions

Simple Summary

Cancers arising from the lining of the uterus, endometrial cancers, are the most common gynecologic malignancy in the United States. Once endometrial cancer escapes the uterus and grows in distant locations, there are limited therapeutic options. The most aggressive and lethal endometrial cancers carry alterations in the protein p53, which is a critical guardian of many cellular functions. The role of these p53 alterations in endometrial cancer is not well understood. The goal of this work was to use p53 altered models of endometrial cancer to understand which, if any, therapeutically targetable vulnerabilities these p53 alterations may confer in endometrial cancer. Here we show that many of these p53 altered cells have problems with cell division which can be targeted with novel single and combination therapies. These discoveries may lead to relevant new therapies for difficult to treat advanced stage endometrial cancers.

Abstract

Uterine carcinoma (UC) is the most common gynecologic malignancy in the United States. TP53 mutant UCs cause a disproportionate number of deaths due to limited therapies for these tumors and the lack of mechanistic understanding of their fundamental vulnerabilities. Here we sought to understand the functional and therapeutic relevance of TP53 mutations in UC. We functionally profiled targetable TP53 dependent DNA damage repair and cell cycle control pathways in a panel of TP53 mutant UC cell lines and patient-derived organoids. There were no consistent defects in DNA damage repair pathways. Rather, most models demonstrated dependence on defective G2/M cell cycle checkpoints and subsequent upregulation of Aurora kinase-LKB1-p53-AKT signaling in the setting of baseline mitotic defects. This combination makes them sensitive to Aurora kinase inhibition. Resistant lines demonstrated an intact G2/M checkpoint, and combining Aurora kinase and WEE1 inhibitors, which then push these cells through mitosis with Aurora kinase inhibitor-induced spindle defects, led to apoptosis in these cases. Overall, this work presents Aurora kinase inhibitors alone or in combination with WEE1 inhibitors as relevant mechanism driven therapies for TP53 mutant UCs. Context specific functional assessment of the G2/M checkpoint may serve as a biomarker in identifying Aurora kinase inhibitor sensitive tumors.