The role of microRNA-9 in ovarian and cervical cancers: An updated overview.

Ovarian and cervical cancers are the two most frequent kind of gynaecological cancers (GCs). In spite of advances in prevention, screening and treatment, cervical cancer still leads to an increased morbidity and mortality worldwide. Ovarian cancer is often detected at a late stage, which significantly reduces the effectiveness of available treatments. Therefore, novel methods are desperately needed to improve the clinical care of GC patients. MicroRNAs, also known as short noncoding RNAs (miRNAs/miRs), are a diverse group of RNAs with a length of 22 nucleotides. These typically cause translational repression and mRNA degradation by interacting with target mRNAs' 3' untranslated region (3'-UTR), together with other regions and gene promoters. Under certain conditions, they are also able to activate translation or regulate transcription. It has been demonstrated that miRNAs are crucial to several biological processes leading to tumorigenesis, including GCs. Recent research has shown that miR-9 affects carcinogenesis. In this review, we will provide an overview of current research on the potential utility of miR-9 in the diagnosis, prognosis, and therapy of ovarian and cervical malignancies.

Sarcopenia in gynaecological cancers.

Gynaecological cancers (GCs) comprise a group of cancers that originate in the female reproductive organs. Each GC is unique, with different signs and symptoms, risk factors and therapeutic strategies. Worldwide, the majority of GCs are still associated with high mortality rates, especially ovarian, due to difficulty in early detection. Despite numerous studies on the underlying pathophysiology, research in the field of GCs poses unique scientific and technological challenges. These challenges require a concerted multi- and inter-disciplinary effort by the clinical, scientific and research communities to accelerate the advancement of prognostic, diagnostic, and therapeutic approaches. Sarcopenia is a multifactorial disease which leads to the systemic loss of skeletal muscle mass and function. It can be caused by malignancies, as well as due to malnutrition, physical inactivity, ageing and neuromuscular, inflammatory, and/or endocrine diseases. Anorexia and systemic inflammation can shift the metabolic balance of patients with cancer cachexia towards catabolism of skeletal muscle, and hence sarcopenia. Therefore, sarcopenia is considered as an indicator of poor general health status, as well as the possible indicator of advanced cancer. There is a growing body of evidence showing the prognostic significance of sarcopenia in various cancers, including GCs. This review will outline the clinical importance of sarcopenia in patients with GCs.

Role of Flex-Dose Delivery Program in Patients Affected by HCC: Advantages in Management of Tare in Our Experience.

Background: Introduced in the latest BCLC 2022, endovascular trans-arterial radioembolization (TARE) has an important role in the treatment of unresectable hepatocellular carcinoma (HCC) as a "bridge" or "downstaging" of disease. The evolution of TARE technology allows a more flexible and personalized target treatment, based on the anatomy and vascular characteristics of each HCC. The flex-dose delivery program is part of this perspective, which allows us to adjust the dose and its radio-embolizing power in relation to the size and type of cancer and to split the therapeutic dose of Y90 in different injections (split-bolus). Methods: From January 2020 to January 2022, we enrolled 19 patients affected by unresectable HCC and candidates for TARE treatment. Thirteen patients completed the treatment following the flex-dose delivery program. Response to treatment was assessed using the mRECIST criteria with CT performed 6 and 9 months after treatment. Two patients did not complete the radiological follow-up and were not included in this retrospective study. The final cohort of this study counts eleven patients. Results: According to mRECIST criteria, six months of follow-up were reported: five cases of complete response (CR, 45.4% of cases), four cases of partial response (PR, 36.4%), and two cases of progression disease (PD, 18.2%). Nine months follow-up reported five cases of complete response (CR, 45.4%), two cases of partial response (PR, 18.2%), and four cases of progression disease (PD, 36.4%). No intra and post-operative complications were described. The average absorbed doses to the hepatic lesion and to the healthy liver tissue were 319 Gy (range 133-447 Gy) and 9.5 Gy (range 2-19 Gy), respectively. Conclusions: The flex-dose delivery program represents a therapeutic protocol capable of "saving" portions of healthy liver parenchyma by designing a "custom-made" treatment for the patient.

Endometrial carcinoma in patients under 40 years of age: insights from the Bulgarian Cancer Registry.

OBJECTIVES: We aimed to investigate the overall survival (OS) of young women with endometrial cancer (EC) in Bulgaria and the impact of histological type on survival. MATERIAL AND METHODS: This is a population-wide retrospective study of patients with EC (≤ 40 years at diagnosis) registered at Bulgarian National Cancer Registry (BNCR) between 1993 and 2020. Patients were re-classified according to the 8th edition of the TNM classification. RESULTS: In total, 30 597 patients were registered and histologically confirmed with malignant tumors of the uterine body. From that, 29 065 of them (95%) had ECs, and the rest had sarcomas. Around 1.64% of all malignant tumors of the uterine body are diagnosed in women under the age of 40. Most of them are diagnosed in the early stage. There was no significant difference in median OS for patients diagnosed before or after 2003. In recent years there was a slight improvement in survival and patients from the last cohort of this study had a 5-year survival rate of 92.5%. Patients with favorable pathology (T1, G1/2) had no lymph node involvement at the time of diagnosis and their 10-year survival rate was 94%. CONCLUSIONS: EC in young women is a rare disease. In most cases, patients are diagnosed in early stageT1, G1/2, N0 and their prognosis is excellent. However, the lack of improvement of OS of young patients with EC in the last three decades shows the need for treatment optimization.

The Role of FBXW7 in Gynecologic Malignancies.

The F-Box and WD Repeat Domain Containing 7 (FBXW7) protein has been shown to regulate cellular growth and act as a tumor suppressor. This protein, also known as FBW7, hCDC4, SEL10 or hAGO, is encoded by the gene FBXW7. It is a crucial component of the Skp1-Cullin1-F-box (SCF) complex, which is a ubiquitin ligase. This complex aids in the degradation of many oncoproteins, such as cyclin E, c-JUN, c-MYC, NOTCH, and MCL1, via the ubiquitin-proteasome system (UPS). The FBXW7 gene is commonly mutated or deleted in numerous types of cancer, including gynecologic cancers (GCs). Such FBXW7 mutations are linked to a poor prognosis due to increased treatment resistance. Hence, detection of the FBXW7 mutation may possibly be an appropriate diagnostic and prognostic biomarker that plays a central role in determining suitable individualized management. Recent studies also suggest that, under specific circumstances, FBXW7 may act as an oncogene. There is mounting evidence indicating that the aberrant expression of FBXW7 is involved in the development of GCs. The aim of this review is to give an update on the role of FBXW7 as a potential biomarker and also as a therapeutic target for novel treatments, particularly in the management of GCs.

Cancer of the Cervix in Bulgaria: Epidemiology of a Crisis.

Eastern Europe continues to have the highest rates of cancer of the uterine cervix (CUC) and human papillomavirus (HPV) infection in Europe. AIM: The aim of this study was to investigate CUC trends in Bulgaria in the context of a lack of a population-based screening program and a demographic crisis. METHODOLOGY: This was a retrospective study of 7861 CUC patients who were registered in the Bulgarian National Cancer Registry (BNCR) between 2013 and 2020 and followed up with until March 2022. We used descriptive statistics and modeling to assess temporal trends in new CUC incidence rates and identify factors associated with survival. RESULTS: Bulgaria's population has decreased by 11.5% between 2011 and 2021. The CUC incidence rate decreased from 29.5/100,000 in 2013 to 23.2/100,000 in 2020 but remains very high. The proportion of patients diagnosed in earlier stages of CUC has decreased over time. Up to 19% of patients with CUC in Bulgaria are diagnosed between the age of 35 and 44 years. The median survival was 101.5 months, with some improvement in later years (adjusted HR = 0.83 for 2017-2020). CONCLUSIONS: In countries with well-established population-based screening, CUC is nowadays considered a rare disease. However, it is not considered rare in Bulgaria. Population-based screening starting at an earlier age is the fastest way to improve outcomes.

Extraterrestrial Gynecology: Could Spaceflight Increase the Risk of Developing Cancer in Female Astronauts? An Updated Review.

Outer space is an extremely hostile environment for human life, with ionizing radiation from galactic cosmic rays and microgravity posing the most significant hazards to the health of astronauts. Spaceflight has also been shown to have an impact on established cancer hallmarks, possibly increasing carcinogenic risk. Terrestrially, women have a higher incidence of radiation-induced cancers, largely driven by lung, thyroid, breast, and ovarian cancers, and therefore, historically, they have been permitted to spend significantly less time in space than men. In the present review, we focus on the effects of microgravity and radiation on the female reproductive system, particularly gynecological cancer. The aim is to provide a summary of the research that has been carried out related to the risk of gynecological cancer, highlighting what further studies are needed to pave the way for safer exploration class missions, as well as postflight screening and management of women astronauts following long-duration spaceflight.

Cancer Stem Cells and Their Possible Implications in Cervical Cancer: A Short Review.

Cervical cancer (CC) is the fourth most common type of gynecological malignancy affecting females worldwide. Most CC cases are linked to infection with high-risk human papillomaviruses (HPV). There has been a significant decrease in the incidence and death rate of CC due to effective cervical Pap smear screening and administration of vaccines. However, this is not equally available throughout different societies. The prognosis of patients with advanced or recurrent CC is particularly poor, with a one-year relative survival rate of a maximum of 20%. Increasing evidence suggests that cancer stem cells (CSCs) may play an important role in CC tumorigenesis, metastasis, relapse, and chemo/radio-resistance, thus representing potential targets for a better therapeutic outcome. CSCs are a small subpopulation of tumor cells with self-renewing ability, which can differentiate into heterogeneous tumor cell types, thus creating a progeny of cells constituting the bulk of tumors. Since cervical CSCs (CCSC) are difficult to identify, this has led to the search for different markers (e.g., ABCG2, ITGA6 (CD49f), PROM1 (CD133), KRT17 (CK17), MSI1, POU5F1 (OCT4), and SOX2). Promising therapeutic strategies targeting CSC-signaling pathways and the CSC niche are currently under development. Here, we provide an overview of CC and CCSCs, describing the phenotypes of CCSCs and the potential of targeting CCSCs in the management of CC.

Epithelioid Trophoblastic Tumour: A Case with Genetic Linkage to a Child Born over Seventeen Years Prior, Successfully Treated with Surgery and Pembrolizumab.

Epithelioid trophoblastic tumours are rare neoplasms showing differentiation towards the chorion leave-type intermediate cytotrophoblast, with only a handful of cases being reported in the literature. These tumours are slow-growing and are typically confined to the uterus for extended periods of time. While the pathogenesis is unclear, they are thought to arise from a remnant intermediate trophoblast originating from prior normal pregnancies or, less frequently, gestational trophoblastic tumours. A protracted time period between the gestational event and tumour development is typical. This case describes a 49-year-old previously healthy female who presented with a completely asymptomatic uterine mass, discovered incidentally during a routine gynaecological assessment. The pathological analysis of the hysterectomy specimen confirmed an epithelioid trophoblastic tumour, involving the uterus and cervix. This is a rare gynaecological tumour. A comparative short tandem repeat analysis revealed genetic similarities to a previous healthy gestation seventeen years prior. She was successful treated with adjuvant pembrolizumab, with no evidence of disease recurrence to date.

(In)Distinctive Role of Long Non-Coding RNAs in Common and Rare Ovarian Cancers.

Rare ovarian cancers (ROCs) are OCs with an annual incidence of fewer than 6 cases per 100,000 women. They affect women of all ages, but due to their low incidence and the potential clinical inexperience in management, there can be a delay in diagnosis, leading to a poor prognosis. The underlying causes for these tumors are varied, but generally, the tumors arise due to alterations in gene/protein expression in cellular processes that regulate normal proliferation and its checkpoints. Dysregulation of the cellular processes that lead to cancer includes gene mutations, epimutations, non-coding RNA (ncRNA) regulation, posttranscriptional and posttranslational modifications. Long non-coding RNA (lncRNA) are defined as transcribed RNA molecules, more than 200 nucleotides in length which are not translated into proteins. They regulate gene expression through several mechanisms and therefore add another level of complexity to the regulatory mechanisms affecting tumor development. Since few studies have been performed on ROCs, in this review we summarize the mechanisms of action of lncRNA in OC, with an emphasis on ROCs.

The Role of Omics Approaches to Characterize Molecular Mechanisms of Rare Ovarian Cancers: Recent Advances and Future Perspectives.

Rare ovarian cancers are ovarian cancers with an annual incidence of less than 6 cases per 100,000 women. They generally have a poor prognosis due to being delayed diagnosis and treatment. Exploration of molecular mechanisms in these cancers has been challenging due to their rarity and research efforts being fragmented across the world. Omics approaches can provide detailed molecular snapshots of the underlying mechanisms of these cancers. Omics approaches, including genomics, transcriptomics, proteomics, and metabolomics, can identify potential candidate biomarkers for diagnosis, prognosis, and screening of rare gynecological cancers and can aid in identifying therapeutic targets. The integration of multiple omics techniques using approaches such as proteogenomics can provide a detailed understanding of the molecular mechanisms of carcinogenesis and cancer progression. Further, omics approaches can provide clues towards developing immunotherapies, cancer recurrence, and drug resistance in tumors; and form a platform for personalized medicine. The current review focuses on the application of omics approaches and integrative biology to gain a better understanding of rare ovarian cancers.

LncRNA MORT (ZNF667-AS1) in Cancer-Is There a Possible Role in Gynecological Malignancies?

Gynecological cancers (GCs) are currently among the major threats to female health. Moreover, there are different histologic subtypes of these cancers, which are defined as 'rare' due to an annual incidence of <6 per 100,000 women. The majority of these tend to be associated with a poor prognosis. Long non-coding RNAs (lncRNAs) play a critical role in the normal development of organisms as well as in tumorigenesis. LncRNAs can be classified into tumor suppressor genes or oncogenes, depending on their function within the cellular context and the signaling pathways in which they are involved. These regulatory RNAs are potential therapeutic targets for cancer due to their tissue and tumor specificity. However, there still needs to be a deeper understanding of the mechanisms by which lncRNAs are involved in the regulation of numerous biological functions in humans, both in normal health and disease. The lncRNA Mortal Obligate RNA Transcript (MORT; alias ZNF667-AS1) has been identified as a tumor-related lncRNA. ZNF667-AS1 gene, located in the human chromosome region 19q13.43, has been shown to be silenced by DNA hypermethylation in several cancers. In this review, we report on the biological functions of ZNF667-AS1 from recent studies and describe the regulatory functions of ZNF667-AS1 in human disease, including cancer. Furthermore, we discuss the emerging insights into the potential role of ZNF667-AS1 as a biomarker and novel therapeutic target in cancer, including GCs (ovarian, cervical, and endometrial cancers).

An Overview of the Role of Long Non-Coding RNAs in Human Choriocarcinoma.

Choriocarcinoma (CC), a subtype of trophoblastic disease, is a rare and highly aggressive neoplasm. There are two main CC subtypes: gestational and non-gestational, (so called when it develops as a component of a germ cell tumor or is related to a somatic mutation of a poorly differentiated carcinoma), each with very diverse biological activity. A therapeutic approach is highly effective in patients with early-stage CC. The advanced stage of the disease also has a good prognosis with around 95% of patients cured following chemotherapy. However, advancements in diagnosis and treatment are always needed to improve outcomes for patients with CC. Long non-coding (lnc) RNAs are non-coding transcripts that are longer than 200 nucleotides. LncRNAs can act as oncogenes or tumor suppressor genes. Deregulation of their expression has a key role in tumor development, angiogenesis, differentiation, migration, apoptosis, and proliferation. Furthermore, detection of cancer-associated lncRNAs in body fluids, such as blood, saliva, and urine of cancer patients, is emerging as a novel method for cancer diagnosis. Although there is evidence for the potential role of lncRNAs in a number of cancers of the female genital tract, their role in CC is poorly understood. This review summarizes the current knowledge of lncRNAs in gestational CC and how this may be applied to future therapeutic strategies in the treatment of this rare cancer.

Adenosquamous Carcinoma of the Uterine Cervix - Impact of Histology on Clinical Management.

INTRODUCTION: Historically, the incidence rate of cervical cancer (CC) in Eastern Europe and particularly in Bulgaria has constantly been higher than that in the other European countries. Adenosquamous carcinoma (ASC) is a rare histological subtype of CC with incidence rate of less than 6 per 100,000. We aimed to analyze the epidemiology and prognosis of all Bulgarian patients with ASC, registered at the Bulgarian National Cancer Registry (BNCR), and to compare patients' characteristics and outcomes with those of patients, treated at a large specialized institution - the Department of Gynecologic Oncology, University Hospital in Pleven, Bulgaria. MATERIALS AND METHODS: This is a retrospective study of all cases of ASC, registered at the BNCR for a 10-year period of time. The Kaplan-Meier analysis with Log rank test was used to estimate the significant differences. RESULTS: The incidence rate of ASC was calculated as 3.2% of all CC registered in BNCR and 4.97% of all stage I patients, treated in our department. The 5-year overall survival (OS) rate of all patients with ASC tumors from the registry was 50.5%. A total of 171 (48.4%) of the patients had T1 tumors and a 5-year OS of 67.1%. Lymph node status was a significant prognostic factor for OS (p=0.001). Thirty-one patients with T1 tumors and ASC histology were treated in our department for the same period of time. Lymph node metastases were found in 10 of them (32.2%). The 5-year observed OS in ASC group was 74.19%. CONCLUSION: The histological subtype of cancer of the uterine cervix has an impact on prognosis and should not be simply considered as a descriptive characteristic but a poor prognostic feature and should be an integral part of the decision-making in clinical management of patients.

Could MicroRNAs Be Useful Tools to Improve the Diagnosis and Treatment of Rare Gynecological Cancers? A Brief Overview.

Gynecological cancers pose an important public health issue, with a high incidence among women of all ages. Gynecological cancers such as malignant germ-cell tumors, sex-cord-stromal tumors, uterine sarcomas and carcinosarcomas, gestational trophoblastic neoplasia, vulvar carcinoma and melanoma of the female genital tract, are defined as rare with an annual incidence of <6 per 100,000 women. Rare gynecological cancers (RGCs) are associated with poor prognosis, and given the low incidence of each entity, there is the risk of delayed diagnosis due to clinical inexperience and limited therapeutic options. There has been a growing interest in the field of microRNAs (miRNAs), a class of small non-coding RNAs of ∼22 nucleotides in length, because of their potential to regulate diverse biological processes. miRNAs usually induce mRNA degradation and translational repression by interacting with the 3' untranslated region (3'-UTR) of target mRNAs, as well as other regions and gene promoters, as well as activating translation or regulating transcription under certain conditions. Recent research has revealed the enormous promise of miRNAs for improving the diagnosis, therapy and prognosis of all major gynecological cancers. However, to date, only a few studies have been performed on RGCs. In this review, we summarize the data currently available regarding RGCs.

GYNOCARE Update: Modern Strategies to Improve Diagnosis and Treatment of Rare Gynecologic Tumors­Current Challenges and Future Directions

More than 50% of all gynecologic tumors can be classified as rare (defined as an incidence of ≤6 per 100,000 women) and usually have a poor prognosis owing to delayed diagnosis and treatment. In contrast to almost all other common solid tumors, the treatment of rare gynecologic tumors (RGT) is often based on expert opinion, retrospective studies, or extrapolation from other tumor sites with similar histology, leading to difficulty in developing guidelines for clinical practice. Currently, gynecologic cancer research, due to distinct scientific and technological challenges, is lagging behind. Moreover, the overall efforts for addressing these challenges are fragmented across different European countries and indeed, worldwide. The GYNOCARE, COST Action CA18117 (European Network for Gynecological Rare Cancer Research) programme aims to address these challenges through the creation of a unique network between key stakeholders covering distinct domains from concept to cure: basic research on RGT, biobanking, bridging with industry, and setting up the legal and regulatory requirements for international innovative clinical trials. On this basis, members of this COST Action, (Working Group 1, "Basic and Translational Research on Rare Gynecological Cancer") have decided to focus their future efforts on the development of new approaches to improve the diagnosis and treatment of RGT. Here, we provide a brief overview of the current state-of-the-art and describe the goals of this COST Action and its future challenges with the aim to stimulate discussion and promote synergy across scientists engaged in the fight against this rare cancer worldwide.

Axolotl Ambystoma mexicanum extract induces cell cycle arrest and differentiation in human acute myeloid leukemia HL-60 cells.

Acute myeloid leukemia is the most common form of acute leukemia in adults, constituting about 80% of cases. Although remarkable progress has been made in the therapeutic scenario for patients with acute myeloid leukemia, research and development of new and effective anticancer agents to improve patient outcome and minimize toxicity is needed. In this study, the antitumor activity of axolotl (AXO) Ambystoma mexicanum crude extract was assessed in vitro on the human acute myeloid leukemia HL-60 cell line. The anticancer activity was evaluated in terms of ability to influence proliferative activity, cell viability, cell cycle arrest, and differentiation. Moreover, gene expression analysis was performed to evaluate the genes involved in the regulation of these processes. The AXO crude extract exhibited antiproliferative but not cytotoxic activities on HL-60 cells, with cell cycle arrest in the G0/G1 phase. Furthermore, the AXO-treated HL-60 cells showed an increase in both the percentage of nitroblue tetrazolium positive cells and the expression of CD11b, whereas the proportion of CD14-positive cells did not change, suggesting that extract is able to induce differentiation toward the granulocytic lineage. Finally, the treatment with AXO extract caused upregulation of CEBPA, CEBPB, CEBPE, SPI1, CDKN1A, and CDKN2C, and downregulation of c-MYC. Our data clearly show the potential anticancer activity of Ambystoma mexicanum on HL-60 cells and suggest that it could help develop promising therapeutic agents for the treatment of acute myeloid leukemia.

Anticancer effects of an extract from a local planarian species on human acute myeloid leukemia HL-60 cells in vitro.

Current anti-cancer drugs can cause many undesirable side effects to patients. Thus, there is a constant need to develop alternative therapeutic drugs. Bioactive compounds derived from natural products including animals, plants and microorganisms are being actively studied as sources for anticancer treatments. Freshwater planarians are important models for stem cell research and regeneration. However, to date, no studies on the biological activities of planaria extracts on cancer have been published. The aim of this study was to examine the potential antitumoral activity of the extract from planaria species-Malta (PSM) on human acute myeloid leukemia (AML) HL-60 cells. Antiproliferative activity was studied in terms of proliferation, apoptosis and differentiation. The expression of genes involved in the regulation of these important cellular processes was also analyzed using real-time PCR. PSM extract exhibited a selective cytotoxic effect on HL-60 cells when compared to normal lymphocytes. Furthermore, cell cycle analysis and Annexin V/PI assay showed that the extract induced apoptosis in HL-60 cells. The PSM extract induced myeloid differentiation with HL-60 cells showing a decreased nucleo/cytoplasmic ratio, an increase in nitroblue tetrazolium-positive cells, and CD11b- and CD14-positive cells. Finally, we also found that the PSM extract increased the expression of CEBPA, CEBPB, CEBPE, SPI1, BAX, CDKN1A and CDKN2C; whereas it reduced the expression of c-MYC and BCL2. This is the first study to reveal the antiproliferative, cytotoxic, and differentiation potential of PSM on HL-60 cells and suggests that it may have considerable potential for development as a novel natural product-based anticancer agent against AML.

A loop involving NRF2, miR-29b-1-5p and AKT, regulates cell fate of MDA-MB-231 triple-negative breast cancer cells.

The present study shows that nuclear factor erythroid 2-related factor 2 (NRF2) and miR-29b-1-5p are two opposite forces which could regulate the fate of MDA-MB-231 cells, the most studied triple-negative breast cancer (TNBC) cell line. We show that NRF2 activation stimulates cell growth and markedly reduces reactive oxygen species (ROS) generation, whereas miR-29b-1-5p overexpression increases ROS generation and reduces cell proliferation. Moreover, NRF2 downregulates miR-29b-1-5p expression, whereas miR-29b-1-5p overexpression decreases p-AKT and p-NRF2. Furthermore, miR-29b-1-5p overexpression induces both inhibition of DNA N-methyltransferases (DNMT1, DNMT3A, and DNMT3B) expression and re-expression of HIN1, RASSF1A and CCND2. Conversely, NRF2 activation induces opposite effects. We also show that parthenolide, a naturally occurring small molecule, induces the expression of miR-29b-1-5p which could suppress NRF2 activation via AKT inhibition. Overall, this study uncovers a novel NRF2/miR-29b-1-5p/AKT regulatory loop that can regulate the fate (life/death) of MDA-MB-231 cells and suggests this loop as therapeutic target for TNBC.

Loss of MCL1 function sensitizes the MDA-MB-231 breast cancer cells to rh-TRAIL by increasing DR4 levels.

Triple-negative breast cancer (TNBC) is a form of BC characterized by high aggressiveness and therapy resistance probably determined by cancer stem cells. MCL1 is an antiapoptotic Bcl-2 family member that could limit the efficacy of anticancer agents as recombinant human tumor necrosis factor related apoptosis-inducing ligand (rh-TRAIL). Here, we investigated MCL1 expression in TNBC tissues and cells. We found MCL1 differentially expressed (upregulated or downregulated) in TNBC tissues. Furthermore, in comparison to the human mammary epithelial cells, we found that MDA-MB-231 cells show similar messenger RNA levels but higher MCL1 protein levels, whereas it resulted downregulated in MDA-MB-436 and BT-20 cells. We evaluated the effects of rh-TRAIL and A-1210477, a selective MCL1 inhibitor, on cell viability and growth of MDA-MB-231 cells. We demonstrated that the drug combination reduced the cell growth and activated the apoptotic pathway. Similar effects were observed on three-dimensional cultures and tertiary mammospheres of MDA-MB-231 cells. In MDA-MB-231 cells, after MCL1 silencing, rh-TRAIL confined the cell population in the sub-G0/G1 phase and induced a drop in the mitochondrial transmembrane potential. To understand the molecular mechanism by which the loss of MCL1 function sensitizes the MDA-MB-231 cells to rh-TRAIL, we analyzed by real-time reverse transcription polymerase chain reaction, the expression of genes related to apoptosis, stemness, cell cycle, and those involved in epigenetic regulation. Interestingly, among the upregulated genes through MCL1 silencing or inhibition, there was TNFRSF10A (DR4). Moreover, MCL1 inhibition increased DR4 protein levels and its cell surface expression. Finally, we demonstrated MCL1-DR4 interaction and dissociation of this complex after A-1210477 treatment. Overall, our findings highlight the potential MCL1-roles in MDA-MB-231 cells and suggest that MCL1 targeting could be an effective strategy to overcome TNBC's rh-TRAIL resistance.