Synergistic antitumor effects of combination PI3K/mTOR and MEK inhibition (SAR245409 and pimasertib) in mucinous ovarian carcinoma cells by fluorescence resonance energy transfer imaging

Mucinous Ovarian Carcinoma: Integrating Molecular Stratification into Surgical and Therapeutic Management

Background/Objectives: Mucinous ovarian carcinoma (MOC) is a rare and biologically distinct subtype of epithelial ovarian cancer, typically presenting at an early stage in younger women. Unlike high-grade serous carcinoma, MOC is characterized by unique molecular features-including frequent KRAS mutations and HER2 amplifications-and exhibits limited sensitivity to platinum-based chemotherapy. These differences highlight the need for individualized treatment strategies guided by molecular and histological profiling. This review aims to integrate current evidence on the clinical management of MOC with emerging insights into its molecular biology, with a focus on how these factors influence surgical decision-making, fertility preservation, and adjuvant therapy selection. Methods: We performed a comprehensive narrative review of the literature, synthesizing findings from retrospective cohorts, molecular studies, and clinical guidelines relevant to the surgical, reproductive, and therapeutic management of MOC. Results: Histologic subtype-expansile versus infiltrative-plays a critical role in guiding lymphadenectomy as lymph node metastases are rare (<1%) in expansile tumors but occur in up to 23% of infiltrative cases. Complete surgical staging remains essential for accurate prognostication, yet tailored approaches may reduce overtreatment in low-risk patients. Fertility-sparing surgery (FSS) appears safe in FIGO stage IA expansile MOC, with favorable reproductive outcomes, while higher-stage or infiltrative cases warrant caution. Given MOC's chemoresistance, the role of adjuvant therapy in early-stage disease remains debated. Targeted strategies, including MEK inhibitors and HER2-directed therapies, are under investigation and may benefit selected molecular subgroups. Conclusions: MOC requires a nuanced, biomarker-informed approach. This review advocates for personalized, evidence-based management supported by multidisciplinary evaluation while underscoring the urgent need for prospective studies and biomarker-driven clinical trials.

Controversies in the management of mucinous ovarian tumors

Mucinous ovarian carcinoma (MOC) is a rare subtype of epithelial ovarian cancer, comprising less than 5% of all cases, and distinguished by its unique molecular, histologic, and clinical features. Its rarity and marked differences from other ovarian cancer subtypes have led to significant controversies regarding its diagnosis, surgical strategies, and systemic therapies. Accurate differentiation between primary and metastatic MOCs remains a critical challenge because of their overlapping features with gastrointestinal cancers, often leading to misclassification. This can result in suboptimal management and impaired patient outcomes, thus highlighting the importance of high-quality pathologic reviews. The surgical approach to MOC is highly controversial. In early-stage disease, fertility-sparing surgery should be systematically considered in young patients, although its feasibility requires careful consideration. In addition, systematic staging lymphadenectomy, which has been de-escalated for patients with expansile MOC, is recommended for those with early-stage infiltrative MOC. In advanced-stage disease, where tumors are often bulky and chemoresistant, the benefits of extensive cytoreduction must be balanced against surgical morbidities. MOC poses significant challenges for systemic treatment owing to its poor response rate to standard ovarian cancer chemotherapy regimens. Alternative therapeutic strategies offer promise but lack robust clinical validation, including gastrointestinal-based regimens, HER2-targeted antibody-drug conjugates (eg, trastuzumab deruxtecan), and immune checkpoint inhibitors for microsatellite unstable MOC. Furthermore, pre-clinical and early phase trials have suggested the potential of combination strategies, including RAS pathway and WEE1 inhibitors. Addressing these controversies requires a multidisciplinary approach that underscores the importance of histologic subtyping and molecular profiling to guide personalized treatment. International collaboration is essential for overcoming the rarity of MOC by enabling larger studies and global registries. These efforts are pivotal for improving diagnostic accuracy, expanding therapeutic options, and, ultimately, enhancing outcomes in patients with this challenging malignancy.

Update on Prognostic and Predictive Markers in Mucinous Ovarian Cancer

This review includes state-of-the-art prognostic and predictive factors of mucinous ovarian cancer (MOC), a rare tumor. Clinical, pathological, and molecular features and treatment options according to prognosis are comprehensively discussed. Different clinical implications of MOC are described according to the The International Federation of Gynecology and Obstetrics (FIGO) stage: early MOC (stage I-II) and advanced MOC (stage III-IV). Early MOC is characterized by a good prognosis. Surgery is the mainstay of treatment. Fertility-sparing surgery could be performed in patients who wish to become pregnant and that present low recurrence risk of disease. Adjuvant chemotherapy is not recommended, except in patients with high-risk clinical and pathological features. Regarding the histological features, an infiltrative growth pattern is the major prognostic factor of MOC. Furthermore, novel molecular biomarkers are emerging for tailored management of early-stage MOC. In contrast, advanced MOC is characterized by poor survival. Radical surgery is the cornerstone of treatment and adjuvant chemotherapy is recommended, although the efficacy is limited by the intrinsic chemoresistance of these tumors. Several molecular hallmarks of advanced MOC have been described in recent years (e.g., HER2 amplification, distinct methylation profiles, peculiar immunological microenvironment), but target therapy for these rare tumors is not available yet.

Role of RAS signaling in ovarian cancer

The RAS family of proteins is among the most frequently mutated genes in human malignancies. In ovarian cancer (OC), the most lethal gynecological malignancy, RAS, especially KRAS mutational status at codons 12, 13, and 61, ranges from 6-65% spanning different histo-types. Normally RAS regulates several signaling pathways involved in a myriad of cellular signaling cascades mediating numerous cellular processes like cell proliferation, differentiation, invasion, and death. Aberrant activation of RAS leads to uncontrolled induction of several downstream signaling pathways such as RAF-1/MAPK (mitogen-activated protein kinase), PI3K phosphoinositide-3 kinase (PI3K)/AKT, RalGEFs, Rac/Rho, BRAF (v-Raf murine sarcoma viral oncogene homolog B), MEK1 (mitogen-activated protein kinase kinase 1), ERK (extracellular signal-regulated kinase), PKB (protein kinase B) and PKC (protein kinase C) involved in cell proliferation as well as maintenance pathways thereby driving tumorigenesis and cancer cell propagation. KRAS mutation is also known to be a biomarker for poor outcome and chemoresistance in OC. As a malignancy with several histotypes showing varying histopathological characteristics, we focus on reviewing recent literature showcasing the involvement of oncogenic RAS in mediating carcinogenesis and chemoresistance in OC and its subtypes.

Novel Therapeutic Strategies for Refractory Ovarian Cancers: Clear Cell and Mucinous Carcinomas

Ovarian cancer has the worst prognosis among gynecological cancers. In particular, clear cell and mucinous carcinomas are less sensitive to chemotherapy. The establishment of new therapies is necessary to improve the treatment outcomes for these carcinomas. In previous clinical studies, chemotherapy with cytotoxic anticancer drugs has failed to demonstrate better treatment outcomes than paclitaxel + carboplatin therapy. In recent years, attention has been focused on treatment with molecular target drugs and immune checkpoint inhibitors that target newly identified biomarkers. The issues that need to be addressed include the most appropriate combination of therapies, identifying patients who may benefit from each therapy, and how results should be incorporated into the standard of care for ovarian clear cell and mucinous carcinomas. In this article, we have reviewed the most promising therapies for ovarian clear cell and mucinous carcinomas, which are regarded as intractable, with an emphasis on therapies currently being investigated in clinical studies.

Targeting the PI3K/AKT/mTOR Signaling Pathway in Lung Cancer: An Update Regarding Potential Drugs and Natural Products

Lung cancer is one of the most common cancers and has a high mortality rate. Due to its high incidence, the clinical management of the disease remains a major challenge. Several reports have documented a relationship between the phosphatidylinositol-3-kinase (PI3K)/ protein kinase B (AKT)/ mammalian target of rapamycin (mTOR) pathway and lung cancer. The recognition of this pathway as a notable therapeutic target in lung cancer is mainly due to its central involvement in the initiation and progression of the disease. Interest in using natural and synthetic medications to target these signaling pathways has increased in recent years, with promising results in vitro, in vivo, and in clinical trials. In this review, we focus on the current understanding of PI3K/AKT/mTOR signaling in tumor development. In addition to the signaling pathway, we highlighted the therapeutic potential of recently developed PI3K/AKT/mTOR inhibitors based on preclinical and clinical trials.

Cellular Mechanism of Gene Mutations and Potential Therapeutic Targets in Ovarian Cancer

Ovarian cancer is a common and complex malignancy with poor prognostic outcome. Most women with ovarian cancer are diagnosed with advanced stage disease due to a lack of effective detection strategies in the early stage. Traditional treatment with cytoreductive surgery and platinum-based combination chemotherapy has not significantly improved prognosis and 5-year survival rates are still extremely poor. Therefore, novel treatment strategies are needed to improve the treatment of ovarian cancer patients. Recent advances of next generation sequencing technologies have both confirmed previous known mutated genes and discovered novel candidate genes in ovarian cancer. In this review, we illustrate recent advances in identifying ovarian cancer gene mutations, including those of TP53, BRCA1/2, PIK3CA, and KRAS genes. In addition, we discuss advances in targeting therapies for ovarian cancer based on these mutated genes in ovarian cancer. Further, we associate between detection of mutation genes by liquid biopsy and the potential early diagnostic value in ovarian cancer.

An open-label, single-arm, phase II trial of buparlisib in patients with melanoma brain metastases not eligible for surgery or radiosurgery-the BUMPER study

Background

Patients with melanoma brain metastasis (MBM) still carry a dismal prognosis. Preclinical data originated in xenograft models showed that buparlisib therapy was highly effective in therapy-naïve MBM.

Patients and Methods

In this open-label, phase II trial, we investigate the safety and efficacy of monotherapy with buparlisib, a PI3K inhibitor, in patients with asymptomatic MBM who were not candidates for local therapy. These patients had also progressed under immunotherapy if BRAF wild-type or under targeted therapy with BRAF/MEK inhibitors if carrying a BRAFV600E/K mutation. The primary endpoint was the intracranial disease control rate assessed by the investigators. The secondary endpoints were overall response rate, duration of response (DOR) of intracranial disease, overall response, progression-free survival (PFS), overall survival (OS), safety, and tolerability of buparlisib.

Results

A total of 20 patients were screened and 17 patients were treated with buparlisib. Twelve patients had progressed under more than 2 systemic therapy lines and 17 had received at least 1 previous local therapy. There were no intracranial responses. Three patients achieved intracranial stable disease; the median DOR was 117 days. The median PFS was 42 days (95% confidence interval [CI]: 23–61 days) and the median OS was 5.0 months (95% CI: 2.24–7.76 months). No new safety signs were observed.

Conclusions

Buparlisib was well tolerated but no intracranial responses were observed. These results might be explained in part by the inclusion of only heavily pretreated patients. However, preclinical data strongly support the rationale to explore PI3K inhibitor-based combinations in patients with MBM displaying hyperactivation of the PI3K–AKT pathway.

P53 and PIK3CA Mutations in KRAS/HER2 Negative Ovarian Intestinal-Type Mucinous Carcinoma Associated with Mature Teratoma

Primary ovarian intestinal-type mucinous carcinomas associated with mature teratoma are rare and represent less than 3% of all primary ovarian neoplasms. The molecular profile of these tumors is still controversial. We report here the first case of mucinous ovarian tumor in which mutation of the PIK3CA and P53 genes could be demonstrated by the next generation sequencing technique without KRAS mutation or HER2 amplification. Our data suggest that these mucinous carcinoma variants probably present an extremely complex molecular biology profile that should be known in the future to stratify therapeutic outcomes and potential targeted therapies, particularly in recurrent disease.

Advanced stage primary mucinous ovarian carcinoma. Where do we stand ?

OBJECTIVE

To evaluate factors associated with survival of patients with advanced stage mucinous ovarian carcinoma (MOC) using a large multi-institutional database.

METHODS

Patients diagnosed between 2004 and 2014 with advanced stage (III-IV) MOC were identified within the National Cancer Database. Those without a personal history of another primary tumor who received cancer-directed surgery with a curative intent were selected for further analysis. Overall survival (OS) was evaluated with Kaplan-Meier curves, and compared with the log-rank test. Multivariate Cox analysis was performed to identify independent predictors of survival.

RESULTS

A total of 1509 patients with a median age of 59 years (IQR 20) met the inclusion criteria: stage III (n = 1045, 69.3%) and stage IV disease (n = 464, 30.7%). Patients who received chemotherapy (n = 1065, 70.6%) had better OS compared to those who did not (n = 385, 25.5%), (median OS 15.44 vs 5.06 months, p < 0.001). The type of reporting facility (p = 0.65) and the year of diagnosis (p = 0.27) were not associated with OS. Presence of residual disease was strongly associated with OS (p < 0.001). After controlling for confounders, the administration of chemotherapy (HR 0.63, 95% CI 0.55, 0.72) was associated with better survival.

CONCLUSION

Advanced stage MOC has an extremely poor prognosis. Patients who received chemotherapy had a small improvement in survival. Every effort to achieve complete gross resection should be performed. Given no improvement in survival outcomes over time, there is an eminent need for novel treatment options.

Low-dose triple drug combination targeting the PI3K/AKT/mTOR pathway and the MAPK pathway is an effective approach in ovarian clear cell carcinoma

Advanced stage ovarian clear cell carcinoma (OCCC) is poorly responsive to platinum-based chemotherapy and has an unfavorable prognosis. Previous studies revealed heterogeneous mutations in PI3K/AKT/mTOR and MAPK pathway nodules converging in mTORC1/2 activation. Here, we aimed to identify an effective low-dose combination of PI3K/AKT/mTOR pathway and MAPK pathway inhibitors simultaneously targeting key kinases in OCCC to preclude single-inhibitor initiated pathway rewiring and limit toxicity. Small molecule inhibitors of mTORC1/2, PI3K and MEK1/2 were combined at monotherapy IC₂₀ doses in a panel of genetically diverse OCCC cell lines (n = 7) to determine an optimal low-dose combination. The IC₂₀ dose triple combination reduced kinase activity in PI3K/AKT/mTOR and MAPK pathways, prevented single-inhibitor induced feedback mechanisms and inhibited short and long-term proliferation in all seven cell lines. Finally, this low-dose triple drug combination treatment significantly reduced tumor growth in two genetically characterized OCCC patient-derived xenograft (PDX) models without resulting in weight loss in these mice. The effectiveness and tolerability of this combined therapy in PDX models warrants clinical exploration of this treatment strategy for OCCC and might be applicable to other cancer types with a similar genetic background.

An international, phase III randomized trial in patients with mucinous epithelial ovarian cancer (mEOC/GOG 0241) with long-term follow-up: and experience of conducting a clinical trial in a rare gynecological tumor

OBJECTIVES

We evaluated four different treatment regimens for advanced-stage mucinous epithelial ovarian cancer.

METHODS

We conducted a multicenter randomized factorial trial (UK and US). Patients were diagnosed with primary mEOC: FIGO stage II-IV or recurrence after stage I disease. Treatment arms were paclitaxel-carboplatin, oxaliplatin-capecitabine, paclitaxel-carboplatin-bevacizumab, or oxaliplatin-capecitabine-bevacizumab. Chemotherapy was given 3-weekly for 6 cycles, and bevacizumab (3-weekly) was continued as maintenance (for 12 cycles). Endpoints included overall-survival (OS), progression-free survival (PFS), toxicity and quality of life (QoL).

RESULTS

The trial stopped after 50 patients were recruited due to slow accrual. Median follow-up was 59 months. OS hazard ratios (HR) for the two main comparisons were: 0.78 (p = 0.48) for Oxal-Cape vs. Pac-Carbo (each with/without bevacizumab), and 1.04 (p = 0.92) for bevacizumab vs. no bevacizumab. Corresponding PFS HRs were: 0.84 and 0.80. Retrospective central pathology review revealed only 45% (18/40) cases with available material had confirmed primary mEOC. Among these, OS HR for Oxal-Cape vs. Pac-Carbo was 0.36 (p = 0.14); PFS HR = 0.62 (p = 0.40). Grade 3-4 toxicity was seen in 61% Pac-Carbo, 61% Oxal-Cape, 54% Pac-Carbo-Bev, and 85% Oxal-Cape-Bev. QoL was similar between the four arms.

CONCLUSION

mEOC/GOG0241 represents an example of a randomized rare tumor trial. Logistical challenges led to early termination, including difficulties in local histopathological diagnosis and accessing drugs outside their labelled indication. There was misalignment between central funders who support clinical trials in rare cancers and the deprioritisation of such work by those managing and funding research at a local level. Rare cancer trials should include centralised pathology review before treatment. Clinical trial registry number: ISRCTN83438782.

Kaempferol, a natural dietary flavonoid, suppresses 17β-estradiol-induced survivin expression and causes apoptotic cell death in endometrial cancer

Endometrioid endometrial carcinoma, commonly known as type 1 endometrial cancer, accounts for >80% of endometrial carcinomas and is dependent on estrogen. We recently reported on the prognostic significance of the BIRC5 survivin gene in endometrial cancer. Estradiol induces survivin expression in estrogen receptor-positive, but not in estrogen receptor-negative, cancer cells. Kaempferol, a bioflavonoid, reportedly inhibits estrogen receptor-α (ERα) in hormone receptor-positive breast cancer cells. However, whether kaempferol-mediated inhibition of ERα suppresses survivin and induces cell death in endometrial cancer remains unclarified. The present study evaluated the antitumor effects of kaempferol on endometrial cancer cells. Cell viability assays, flow cytometry analysis, western blotting and annexin V analyses were used to analyze the antitumor effects of kaempferol. The results demonstrated that kaempferol successfully suppressed the viability of two ER-positive endometrial cancer cell lines, with IC₅₀ values of 83 and 65 µM. In addition, kaempferol induced sub-G1 cell accumulation and apoptotic cell death (P<0.01) in a dose-dependent manner. Treatment of cells with estradiol significantly induced co-expression of nuclear ERα and survivin proteins (P<0.001). Further evaluation revealed that kaempferol causes apoptotic cell death largely by suppressing ERα, survivin and Bcl-2 protein. Therefore, the results of the present study suggested that targeting ERα and survivin with kaempferol may be a novel therapeutic option against endometrial carcinoma.

Recent Insights into Mucinous Ovarian Carcinoma

Ovarian mucinous tumors represent a group of rare neoplasms with a still undefined cell of origin but with an apparent progression from benign to borderline to carcinoma. Even though these tumors are different from the other histological subtypes of epithelial ovarian neoplasms, they are still treated with a similar chemotherapeutic approach. Here, we review its pathogenesis, molecular alterations, (differential) diagnosis, clinical presentation and current treatment, and how recent molecular and biological information on this tumor might lead to better and more specific clinical management of patients with mucinous ovarian carcinoma.

Pharmacology of Pimasertib, A Selective MEK1/2 Inhibitor

Pimasertib belongs to the growing family of mitogen activated protein kinase (MEK1/2) inhibitors undergoing clinical development for various cancer indications. Since the MEK inhibition in several cell signalling transduction cascades within tumours was considered therapeutically beneficial, number of clinical investigations of pimasertib have been reported. Despite being orally bioavailable in cancer patients, pimasertib undergoes faster clearance with a short elimination half-life. In addition, due to occurrence of toxicity, the development of pimasertib appears to be stalled. Case studies are provided on the possible utilization of pimasertib in combination therapies with other approved drugs. Based on the review, it appeared that there was the need to identify the optimal dose and the dosing regimen of pimasertib to provide a balance between safety and efficacy when combined with approved therapies.

Early stage mucinous ovarian cancer: A review

Mucinous ovarian carcinomas (MOCs) are an uncommon subset of epithelial neoplasms, both clinically and molecularly distinct from other ovarian cancers. Pathologic diagnosis proves challenging, and metastatic disease from other sites-especially the digestive tract-must be excluded. Fortunately, most patients are diagnosed at an early stage of disease and often present with large, unilateral adnexal masses. Survival for patients with stage IA disease approaches over 90%, and surgery alone is sufficient. Patients with stage IB-II disease should receive adjuvant treatment but the specific regimen is controversial. In the following review, we provide an overview of mucinous ovarian carcinomas, with a particular focus on the treatment of patients with early stage disease.

Differential compensation mechanisms define resistance to PI3K inhibitors in PIK3CA amplified HNSCC

OBJECTIVE

Recent sequencing studies of head and neck squamous cell carcinomas (HNSCCs) have identified the phosphatidylinositol 3-kinase (PI3K) pathway as the most frequently mutated, oncogenic pathway in this cancer type. Despite the frequency of activating genomic alterations in PIK3CA (the gene encoding the catalytic subunit of PI3K, targeted inhibitors of PI3K have not shown clinical efficacy as monotherapies. We hypothesized that co-dependent pathways, including the Ras-MEK-ERK pathway, may still be functional in the presence of PI3K inhibitors and might serve as mediators of this resistance.

METHODS

We assessed the hypothesis using resazurin cell viability and trypan blue exclusion assays. We also used Western blot to characterize Ras-MEK-ERK pathway activity.

STUDY DESIGN

We evaluated this hypothesis in six PIK3CA-amplified, PI3K inhibitor-resistant HNSCC cell lines following treatment with pan and alpha-isoform selective PI3K inhibitors (BKM120 and HS-173 respectively). We also tested the effect of combination treatment with PI3K inhibitor HS-173 and MEK inhibitor trametinib or EGFR inhibitor gefitinib.

RESULTS

Our results displayed maintenance of Ras-MEK-ERK pathway activity in 4 of 6 HNSCC cell lines after PI3K inhibitor treatment. We also found that UM-SCC-69 and UM-SCC-108 cells display synergistic responses to dual therapy.

CONCLUSION

This study suggests that inhibition of the PI3K and Ras-MEK-ERK pathways might be effective in some HNSCC patients; however, it also prompts the study of additional resistance mechanisms to identify synergistic combination therapies for tumors resistant to these di-therapies.