Tagged: Cancer Stem Cell

Targeting Stem Cell-like Traits: How miR-10b Inhibition Treats Metastatic Breast Cancer

October 11, 2024

“Our results demonstrate that inhibition of miR-10b using MN-anti-miR10b decreases the stemness of breast cancer cells, supporting dedifferentiation as a mechanism through which the nanodrug may function as a therapy.”

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While there have been significant improvements in breast cancer detection and treatment, the outlook for metastatic breast cancer remains bleak, with only a 30% five-year survival rate. This is largely due to existing therapies’ inability to effectively target the unique characteristics of metastatic cells. One key factor in metastasis is miR-10b, a small noncoding RNA known to influence cancer cell invasion, migration, viability, and proliferation.

In their paper, researchers Alan Halim, Nasreen Al-Qadi, Elizabeth Kenyon, Kayla N. Conner, Sujan Kumar Mondal, Zdravka Medarova, and Anna Moore from Michigan State University’s Precision Health Program, College of Human Medicine, and College of Veterinary Medicine, and Transcode Therapeutics Inc. in Newton, Massachusetts, shared findings showing that inhibiting miR-10b impairs breast cancer cell stemness. Their research paper, entitled, “Inhibition of miR-10b treats metastatic breast cancer by targeting stem cell-like properties” was published in Volume 15 of Oncotarget on August 26, 2024.

THE STUDY

In this study, researchers investigated the effects of repeated MN-anti-miR10b treatments on local and distant metastases. They observed over 93% inhibition of miR-10b in cryosectioned samples and noted reduced miR-10b expression in lymph node and lung metastases after weekly dosing. RNA sequencing revealed upregulation of genes, including ATP6V0D2, EPHB2, KLF4, KLF7, NCOR2, TMEM268, and VDR, associated with developmental processes. Functional enrichment analysis highlighted biological processes such as cell differentiation and tissue development in these upregulated genes.

The researchers also explored the link between miR-10b expression and stem-like properties in cancer cells. Elevated miR-10b levels were found in stem-like breast cancer cells. MN-anti-miR10b reduced stemness-related traits in MDA-MB-231 and MCF-7 cells, as shown by reduced aldehyde dehydrogenase activity and smaller spheroids in tumorsphere assays. These results suggest that inhibiting miR-10b effectively targets stem-like properties in metastatic breast cancer, offering potential therapeutic benefits.

DISCUSSION

Inhibition of miR-10b has been shown to be an effective treatment strategy for metastatic breast cancer. The nanodrug MN-anti-miR10b was found to significantly downregulate miR-10b expression in cancer cells, leading to decreased cell migration, invasion, proliferation, and viability. The researchers investigated the time course of miR-10b inhibition and confirmed that the nanodrug effectively reduced miR-10b expression in both regional and distant metastases. RNA sequencing analysis revealed that the inhibition of miR-10b by MN-anti-miR10b upregulated genes associated with developmental processes, indicating an effect on the stem cell-like properties of cancer cells.

The study also demonstrated a correlation between miR-10b expression and stemness in cancer cells. Cells with increased stemness, identified by the CD44+/CD24- surface marker phenotype, showed higher miR-10b expression. Treatment with MN-anti-miR10b resulted in decreased stemness-associated properties, as observed through the Aldefluor assay and tumorsphere formation assays. These findings suggest that MN-anti-miR10b has a differentiation effect on cancer cells and targets dedifferentiated, stem cell-like cancer cells. The upregulation of genes associated with developmental processes by MN-anti-miR10b further supports the notion that cancer cells overexpressing miR-10b are in a less-developed, more stem cell-like state.

Overall, the study provides valuable insights into the therapeutic effects of miR-10b inhibition using MN-anti-miR10b in metastatic breast cancer. The findings suggest that targeting miR-10b and stem cell-like properties in cancer cells could be a promising approach for the treatment of various types of metastatic carcinoma.

IN CONCLUSION

Despite the progress made in breast cancer detection and treatment, the prognosis for metastatic breast cancer remains poor. A significant factor contributing to metastasis is miR-10b, a small RNA molecule involved in cancer cell invasion and migration. The researchers have developed a nanodrug called MN-anti-miR10b that delivers antisense oligomers to inhibit miR-10b in cancer cells.

In mouse models of metastatic triple-negative breast cancer, MN-anti-miR10b has shown promising results. It prevents the development of metastases and can eliminate existing metastases when combined with chemotherapy, even after treatment cessation. Recent studies have also linked miR-10b to the acquisition of stem cell-like properties in cancer cells, including chemotherapy resistance.

In this study, the researchers provide transcriptional evidence that inhibiting miR-10b with MN-anti-miR10b activates developmental processes in cancer cells. They also demonstrate that stem-like cancer cells have higher expression of miR-10b. Importantly, treatment of breast cancer cells with MN-anti-miR10b reduces their stemness, indicating that the nanodrug can effectively target and impair the stem-like properties of breast cancer cells.

These findings highlight the potential of MN-anti-miR10b as a treatment option for breast cancer subtypes characterized by stem-like properties. By inhibiting miR-10b, the nanodrug could disrupt the stemness of cancer cells and may offer a new approach to improve the outcomes for metastatic breast cancer patients.

Click here to read the full research paper in Oncotarget.

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Trending With Impact: Targeted Treatment for Recurrent Ovarian Cancer

July 15, 2021

In this 2018 paper, researchers studied a new targeted strategy to treat ovarian cancer.

Anatomy and physiology of Ovary under the microscopic in laboratory.

The Trending with Impact series highlights Oncotarget publications attracting higher visibility among readers around the world online, in the news, and on social media—beyond normal readership levels. Look for future science news about the latest trending publications here, and at Oncotarget.com.

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Sialyl-Thomsen-nouveau (STn)—a tumor stem cell-associated carbohydrate antigen—is a moiety. “Moiety” is a term used to name molecular particles identified among multiple types of molecules. STns have been found on protein markers of cancer stem cells (CSCs) in pancreatic, colon, and gastric malignancies. Researchers hypothesize that CSCs can survive adjuvant chemotherapy and are responsible for tumor resurgence in many cancers, including recurrent ovarian cancer (OvCa).

“Unfortunately, despite aggressive surgery and adjuvant chemotherapy, most women with OvCa develop recurrent disease that is ineffectively treated with current therapies. Novel treatment strategies are urgently needed to target chemoresistant disease.”

Researchers from Massachusetts General Hospital, Siamab Therapeutics, Inc., and Harvard Medical School conducted a novel research study in 2018 and authored a paper published by Oncotarget, entitled, “Treatment of ovarian cancer by targeting the tumor stem cell-associated carbohydrate antigen, Sialyl-Thomsen-nouveau.”

“Accumulating research has revealed not only the importance of CSCs in tumor initiation, metastasis, recurrence, and chemoresistance, but also the potential of CSC-directed therapies to impact patient survival.”

The Study

Researchers often use CD133 (a cell surface antigen) as a marker to detect and sequester CSCs in various solid tumors. In this study, the team analyzed the expression of STn and CD133 in ovarian cancer cell lines, their colony and sphere formation capacity, response to cytotoxic chemotherapy, and STn’s response to two targeted antibody drug conjugate (anti-STn-ADC) treatments in vivo and in vitro.

“Analyses of colony and sphere forming capacity and of response to standard-of-care cytotoxic therapy suggest a subset of OvCa STn+ cells display some CSC features.”

In a subset of human OvCa cell lines, the researchers found that STn and CD133 were co-expressed. They also found that STn+ and CD133+ cells have increased colony formation capacity and elevated levels of STn increases sphere formation. Both of the anti-STn-ADC treatments had anti-cancer effects in the OvCa cell lines in vivo and in vitro. These findings show that STn demonstrates some stem-like properties and may be a viable therapeutic target in ovarian cancer.

“In summary, STn+ cells demonstrate some stem-like properties and specific therapeutic targeting of STn in ovarian tumors may be an effective clinical strategy to eliminate both STn+ CSC and STn+ non-CSC populations.”

Conclusion

“Our finding that targeting STn+ cells in vivo with a highly specific antibody conjugated to auristatin resulted in marked decreases in tumor burden without any obvious toxicity suggests that an anti-STn ADC approach may serve as a viable option in eliminating non-CSC as well as some CSC populations.”

Click here to read the full scientific study, published by Oncotarget.

Oncotarget

Trending with Impact: Crosstalk In the Tumor Microenvironment

February 25, 2021

Authors of this review paper discuss the complex crosstalk between cancer stem cells and macrophages, and potential anti-cancer strategies for future studies.

Figure 1: Main roles of tumor associated macrophages in cancer development and maintenance. — **Figure 1:** Main roles of tumor associated macrophages in cancer development and maintenance.

The Trending with Impact series highlights Oncotarget publications attracting higher visibility among readers around the world online, in the news, and on social media—beyond normal readership levels. Look for future science news and articles about the latest trending publications here, and at Oncotarget.com.

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A review paper published by researchers from the University of Modena and Reggio Emilia in Italy and the Sulaiman AlRajhi Medical School in Saudi Arabia is trending and titled, “Cancer stem cells and macrophages: molecular connections and future perspectives against cancer.”

“The aim of this review is to define the complex crosstalk between these two cell types and to highlight potential future anti-cancer strategies,” Dr. Beatrice Aramini said, a thoracic surgeon and scientist from the University Hospital of Modena Reggio Emilia.

There have been numerous studies published over recent decades in an effort to understand the molecular mediators of cancer stem cells (CSCs) and tumor associated macrophages (TAMs). Several studies have contributed to bringing light to some of the complex crosstalk that occurs between these two cell types and within the tumor microenvironment. The authors of this review paper reference hundreds of studies and offer a thorough audit and analysis of the current state of this research.

About the Writers of the Review Article

“I mainly focus on lung cancer,” Dr. Aramini said. “I started this project about cancer stem cells in lung cancer since 2017, at University Hospital of Modena Reggio Emilia, joining the laboratory of cell therapies directed by Professor Massimo Dominici with the chief of medical oncology at University Hospital in Modena.”

Dr. Valentina Masciale, co-author, is a research fellow at the University Hospital of Modena Reggio Emilia. Dr. Masciale’s professional experience began by studying missing stroma cells. She then studied stem cells in regenerative medicine and currently she is working with Dr. Aramini on a project focused on lung cancer stem cells. The paper they wrote was revised and approved by seven other contributing authors.

“In this review, we describe the importance of cancer stem cells as the key drivers of cancer initiation and progression due to their unlimited cell renewal capacity and their ability to induce tumor formation,” Dr. Aramini said.

Introduction to Cancer Stem Cells

“Cancer stem cells (CSCs) constitute a cancer cell subpopulation similar to the other stem cell types in terms of self-renewal and multilineage differentiation potential but drive tumor development besides heterogeneity and dissemination of cancer cells [1–9].”

In 1997, Bonnet and Dick were the first researchers to report the existence of cancer stem cells in the tumor, in acute myeloid leukaemia. Since then, however, a standard marker to identify CSCs still has yet to be found.

“One of the main obstacles to proving the CSC model is the difficulty in identification and isolation of these cells [7, 33, 91].”

The authors explain that one of the problems with finding a marker such as this is that many markers found are not only able to detect CSCs, but they also detect non-tumor cells. This represents a major obstacle when developing new therapies to target CSCs only. The authors note that recently there have been several gene markers described by researchers for CSCs in different tumors, including brain, breast, blood, and lung.

“Indeed, there are currently no markers able to distinguish between stem cells and CSCs. Thus far, the best markers identified are those of onco-fetal stem cells, which are absent in adult organs and present in cancer cells [45–48].”

Theories About the Role of Cancer Stem Cells

This review refers to a few theories about the role of CSCs in cancer progression. One theory is based on the premise that tumor tissue is hierarchically organized into different types of cells, with the CSC subpopulation as the top of this hierarchy. In this theory, the other levels consist of additional differentiated tumor cells or cells with a limited proliferative potential. The “clonal evolution theory” hypothesizes that a rampant mutating cell is the catalyst for tumor progression.

“Peter Nowell was the first to describe the ‘clonal evolution theory,’ defining cancer as a complex process resulting from the development of a single out-of-control cell with multiple cell mutations that result in the progression of the tumor, which is kept viable through the selection of the most aggressive clones [89].”

Since the discovery of CSC plasticity and the possibility of switching from stem to non-stem cells, researchers have gained a more complex picture of the origin of tumor heterogeneity and more theories about the role of cancer stem cells in tumor progression.

“An opposing theory is based on the concept that CSCs are a group of cells endowed with a high self-renewal capacity that can set different phenotypes of tumorigenic cells [18, 88].”

Cancer Stem Cells and Macrophages

The researchers explain that macrophages are large specialized phagocytic cells that exist in tissues or at infection sites which act as part of the immune system. Arising from the bone marrow, macrophages perform multiple functions and roles in normal and tumor microenvironments, including pro-inflammatory activities and anti-inflammatory processes. Tumor-associated macrophages (TAM) comprise up to 50% of the tumor mass and have a close relationship with CSCs.

“The rising interest on these type of cells comes from recent study demonstrating that high number of tumor-associated macrophages correlate with the poor clinical prognosis in many solid tumors, including lung cancer, which is the field of our research group at the University Hospital of Modena,” Dr. Masciale said. “Another important aspect is the protective role of the tumor-associated macrophages play on tumors undergoing chemotherapy, which may impact the chemotherapy resistance and consequent tumor relapse.”

In recent studies, high numbers of TAMs in lung tumors, gastric cancer, and other cancer types, have been shown to correlate with a poor clinical prognosis. Macrophages are recruited to the tumor and, through crosstalk, provide protection to the tumor, contribute to immunosuppression in the tumor microenvironment and, eventually, drug resistance.

“The primary cause of failure in cancer treatment is the emergence of drug resistance that promotes the tumor spreading,” Dr. Masciale said.

“Cross-talk between CSCs and TAMs involves the recruitment of TAMs through vascularization and the release of chemokines by TAMs to preserve the quiescence of CSCs and modification of their antigens to escape from recruitment by immune cells.”

Future Perspectives

“Although most TAM-targeting strategies are in the pre-clinical stages, several factors used for TAMs depletion have already been tested in clinical trials [271, 272].”

Current efforts are underway to reprogram or inhibit the tumor-protective properties of tumor associated macrophages. Researchers are also investigating potential strategies to increase the efficacy of chemotherapy through nano-drug delivery to TAMs.

“Due to the significance of the tasks in which TAMs are involved, TAMs are increasingly becoming principal targets of novel therapeutic approaches, especially in the field of nanomedicine.”

The authors believe that targeting TAMs could trigger various reactions in the tumor, which are difficult to predict even given the individual variability from patient to patient. They also explain that targeting TAMs with CSCs offers another potential for treating different tumors to better control cancer progression and avoid tumor dissemination.

“In summary, generating new information about the interaction between TAMs and CSCs will be one of the most important challenges for the development of more effective targeted cancer therapies.”

Click here to read the full scientific review, published in Oncotarget.

Click here to read or watch an interview with the authors Behind the Study.

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