Cancer reversion with oocyte extracts is mediated by cell cycle arrest and induction of tumour dormancy

miRNAs from Zebrafish Embryo Extracts Inhibit Breast Cancer Invasiveness and Migration by Modulating miR-218-5p/PI3K Pathway

Herein, we demonstrate that soluble factors extracted from the distinct phases of the development of zebrafish embryos (ZFEs) exhibit a specific miRNA profile. We removed proteins and concentrated miRNAs in different phase-related samples, which we investigated further. We observed that ZFEs modulate miRNA expression in both normal and cancerous breast cells, significantly inhibiting the invasiveness and motility of triple-negative breast cancer cells. Namely, ZFEs reactivate the synthesis of miR-218-5p in cancerous cells, leading to the downregulation of PI3K, which consequently alters the distribution of phosphoinositides (such as PIP2/PIP3). Moreover, the silencing of miR-218-5p abolished the ZFE effects. Restoring a proper PIP2/PIP3 ratio is crucial for promoting the regression of the malignant phenotype. Phenotypic reversion follows the extensive cytoskeleton rearrangement and the re-emergence of E-cadherin/β-catenin complexes. In addition, ZFEs antagonize the Epithelial Mesenchymal Transition (EMT) by modulating several pathways, including the TCTP-p53 axis. Overall, these results show that embryo extracts enriched with fish miRNAs reactivate endogenous miR-218-5p in cancerous cells, which in turn downregulates critical pathways involved in tumor progression and metastasis.

Apolipoproteins have a major role in cellular tumor dormancy in triple negative breast cancer: In-silico study

Triple-negative breast cancer (TNBC) lacks estrogen, progesterone, and human epidermal growth factor receptors and has a poor prognosis as it is resistant to chemotherapy. A new treatment option for this type of cancer may be by putting these malignant cells into dormancy. The oocyte's embryonic milieu presents a unique tumor reversion microenvironment by inducing growth arrest and changing cells' phenotypes. We conducted an in-silico study to determine the most likely oocyte extract (OE) proteins involved in inducing dormancy using HDock, CluPro, and molecular dynamic (MD) simulation. Results showed low energy scores for complexes between OE proteins and four surface markers: K1C14, CLD3, CLD4, and ITA6. Apolipoprotein A1 (APOA1) and Apolipoprotein C3 (APOC3) showed the highest stability and affinity with these four surface markers: K1C14, CLD3, CLD4, and ITA6. These proteins are involved in key tumor-related pathways such as angiogenesis, proliferation, apoptosis, and migration. This will pave the way for exploring novel therapeutic options to induce dormancy in TNBC cells.

The phenotypic reversion of cancer: Experimental evidences on cancer reversibility through epigenetic mechanisms (Review)

Different experimental models reveal that malignant cancer cells can be induced to change their phenotype into a benign one. This phenotypic transformation, confirmed both in vitro and in vivo, currently is known as 'tumor reversion'. This evidence raises a radical question among current cancer models: Is cancer reversible? How do genetic and epigenetic alterations hierarchically relate? Understanding the mechanisms of 'tumor reversion' represents a key point in order to evolve the actual cancer models and develop new heuristic models that can possibly lead to drugs that target epigenetic mechanisms, for example epigenetic drugs. Even though evidence of tumor reversion dates back to the 1950s, this remains a completely new field of research recently re‑discovered thanks to the interest in cell reprogramming research, developmental biology and the increasing understanding of epigenetic mechanisms. In the current review, a comprehensive review of all the main experimental models on tumor reversion was presented.

Dormant cancer cells and polyploid giant cancer cells: The roots of cancer recurrence and metastasis

Tumour cell dormancy is critical for metastasis and resistance to chemoradiotherapy. Polyploid giant cancer cells (PGCCs) with giant or multiple nuclei and high DNA content have the properties of cancer stem cell and single PGCCs can individually generate tumours in immunodeficient mice. PGCCs represent a dormant form of cancer cells that survive harsh tumour conditions and contribute to tumour recurrence. Hypoxic mimics, chemotherapeutics, radiation and cytotoxic traditional Chinese medicines can induce PGCCs formation through endoreduplication and/or cell fusion. After incubation, dormant PGCCs can recover from the treatment and produce daughter cells with strong proliferative, migratory and invasive abilities via asymmetric cell division. Additionally, PGCCs can resist hypoxia or chemical stress and have a distinct protein signature that involves chromatin remodelling and cell cycle regulation. Dormant PGCCs form the cellular basis for therapeutic resistance, metastatic cascade and disease recurrence. This review summarises regulatory mechanisms governing dormant cancer cells entry and exit of dormancy, which may be used by PGCCs, and potential therapeutic strategies for targeting PGCCs.

Cell-Free Therapies: The Use of Cell Extracts to Mitigate Irradiation-Injured Salivary Glands

Radiotherapy is a standard treatment for head and neck cancer patients worldwide. However, millions of patients who received radiotherapy consequently suffer from xerostomia because of irreversible damage to salivary glands (SGs) caused by irradiation (IR). Current treatments for IR-induced SG hypofunction only provide temporary symptom alleviation but do not repair the damaged SG, thus resulting in limited treatment efficacy. Therefore, there has recently been a growing interest in regenerative treatments, such as cell-free therapies. This review aims to summarize cell-free therapies for IR-induced SG, with a particular emphasis on utilizing diverse cell extract (CE) administrations. Cell extract is a group of heterogeneous mixtures containing multifunctional inter-cellular molecules. This review discusses the current knowledge of CE's components and efficacy. We propose optimal approaches to improve cell extract treatment from multiple perspectives (e.g., delivery routes, preparation methods, and other details regarding CE administration). In addition, the advantages and limitations of CE treatment are systematically discussed by comparing it to other cell-free (such as conditioned media and exosomes) and cell-based therapies. Although a comprehensive identification of the bioactive factors within CEs and their mechanisms of action have yet to be fully understood, we propose cell extract therapy as an effective, practical, user-friendly, and safe option to conventional therapies in IR-induced SG.

Axolotl: A resourceful vertebrate model for regeneration and beyond

The regenerative capacity varies significantly among the animal kingdom. Successful regeneration program in some animals results in the functional restoration of tissues and lost structures. Among the highly regenerative animals, axolotl provides multiple experimental advantages with its many extraordinary characteristics. It has been positioned as a regeneration model organism due to its exceptional renewal capacity, including the internal organs, central nervous system, and appendages, in a scar-free manner. In addition to this unique regeneration ability, the observed low cancer incidence, its resistance to carcinogens, and the reversing effect of its cell extract on neoplasms strongly suggest its usability in cancer research. Axolotl's longevity and efficient utilization of several anti-aging mechanisms underline its potential to be employed in aging studies.

Prognostic Biomarker NUMB Is Inhibited by Breast Cancer Cell Exosomes to Promote Breast Cancer Progression

Objective

To clarify the regulation of breast cancer cell-derived exosomes on breast cancer and the expression of the NUMB endocytic adaptor protein (NUMB) protein.

Methods

The exosomes of breast cancer cell line MDA-MB-231 were isolated. The exosomes were subsequently labeled with PKH67 and added to breast cancer MDA-MB-231 cells cultured in vitro. Transwell and clone formation assays were performed to detect cell migration, invasion, and clone formation. Meanwhile, Western blot and qPCR were conducted to determine the regulation of NUMB expression by exosomes in breast cancer cells. Furthermore, NUMB overexpressed lentivirus was supplemented to validate the recovery.

Results

The number of migrating and invasive breast cancer cells in the exosome-treated group was significantly increased compared with the control group. Moreover, the number of breast cancer cell clones in the exosome-treated group was increased than in the control group. However, the NUMB expression in breast cancer cells treated with exosomes revealed a substantial decrease, indicating that the exosomes of breast cancer cells could inhibit NUMB expression. NUMB overexpressed lentivirus supplementation markedly suppressed cell migration, invasion, and proliferation of breast cancer cells compared with exosome group.

Conclusion

Taken together, the exosomes of breast cancer cells could inhibit the expression of NUMB and promote the migration, invasion, and cell clone formation of breast cancer cells.

Dormancy: There and Back Again

Many cells are capable of maintaining viability in a non-dividing state with minimal metabolism under unfavorable conditions. These are germ cells, adult stem cells, and microorganisms. Unfortunately, a resting state, or dormancy, is possible for tuberculosis bacilli in a latent form of the disease and cancer cells, which may later form secondary tumors (metastases) in different parts of the body. These cells are resistant to therapy that can destroy intensely dividing cells and to the host immune system. A cascade of reactions that allows cells to enter and exit dormancy is triggered by regulatory factors from the microenvironment in niches that harbor the cells. A ratio of forbidding and permitting signals dictates whether the cells become dormant or start proliferation. The only difference between the cell dormancy regulation in normal and pathological conditions is that pathogens, mycobacteria, and cancer cells can influence their own fate by changing their microenvironment. Certain mechanisms of these processes are considered in the review.

Changes in Lipid Profile and SOX-2 Expression in RM-1 Cells after Co-Culture with Preimplantation Embryos or with Deproteinated Blastocyst Extracts

The embryonic environment can modify cancer cell metabolism, and it is reported to induce the loss of tumorigenic properties and even affect the differentiation of cancer cells into normal tissues....

Tumor reversion: a dream or a reality

Reversion of tumor to a normal differentiated cell once considered a dream is now at the brink of becoming a reality. Different layers of molecules/events such as microRNAs, transcription factors, alternative RNA splicing, post-transcriptional, post-translational modifications, availability of proteomics, genomics editing tools, and chemical biology approaches gave hope to manipulation of cancer cells reversion to a normal cell phenotype as evidences are subtle but definitive. Regardless of the advancement, there is a long way to go, as customized techniques are required to be fine-tuned with precision to attain more insights into tumor reversion. Tumor regression models using available genome-editing methods, followed by in vitro and in vivo proteomics profiling techniques show early evidence. This review summarizes tumor reversion developments, present issues, and unaddressed challenges that remained in the uncharted territory to modulate cellular machinery for tumor reversion towards therapeutic purposes successfully. Ongoing research reaffirms the potential promises of understanding the mechanism of tumor reversion and required refinement that is warranted in vitro and in vivo models of tumor reversion, and the potential translation of these into cancer therapy. Furthermore, therapeutic compounds were reported to induce phenotypic changes in cancer cells into normal cells, which will contribute in understanding the mechanism of tumor reversion. Altogether, the efforts collectively suggest that tumor reversion will likely reveal a new wave of therapeutic discoveries that will significantly impact clinical practice in cancer therapy.

The current paradigm and challenges ahead for the dormancy of disseminated tumor cells

Disseminated tumor cells (DTCs) are known to enter a state of dormancy that is achieved via growth arrest of DTCs and/or a form of population equilibrium state, strongly influenced by the organ microenvironment. During this time, expansion of residual disseminated cancer is paused and DTCs survive to fuel relapse, sometimes decades later. This notion has opened a new window of opportunity for intervening and preventing relapse. Here we review recent data that have further augmented the understanding of cancer dormancy and discuss how this is leading to new strategies for monitoring and targeting dormant cancer.