From Worms to Tumors: Conserved Strategies of Cellular Arrest and Survival Governing Dormancy.

Dormancy is an elusive and deadly component of cancers. Rare, therapy resistant cells lay dormant for decades and when reactivated cause disease progression and relapse. Eradicating dormant cancer cells is key to curing cancers yet is an unrealized goal. The skeleton remains a common location for dissemination and dormancy, yet our understanding of the cellular and molecular pathways that control dormant cancer cells in the the skeleton is limited. We hypothesized that dormant cancer cells occupy a common niche in the skeleton and this supports long-term dormancy. To test this we developed technology to identify and analyse dormant cancers cells from different cancer types and the compartment in the skeleton in which they reside. Membrane label retention was able to distinguish dormant cancer cells from reactivated cancer cells. Intravital imaging showed that dormant cancer cells were found associated with endosteal bone surface suggesting that different cancers may occupy a common niche. Single cell RNA sequencing of dormant cancer cells showed they expressed a distinct gene signature that was enriched for myeloid genes. Single cell RNA sequencing of >130,000 cells isolated from the endosteal bone compartment and the bone marrow identified 32 distinct cell clusters. Detailed transcriptional analysis facilitated construction of a map of all of the cell types/states present in the endosteal bone compartment. In silico ligand/receptor interaction mapping enabled identification of the cell types and the molecular pathways that may mediate dormant cell niche formation in vivo. Non-haemopoietic cells, particularly cells of the osteoblast lineage and endothelia cells were the most enriched for dormant cell binding partners. This was common across three different dormant tumor types. Detailed analysis of cells of the osteoblast lineage showed greatest enrichment for binding partners in LeprHigh/Cxcl12High mesenchymal cells. Further analysis of the molecular pathways that can interact with binding partners identified a number of potential molecular regulators of dormancy. For example, Gas6, which is expressed by LeprHigh/Cxcl12High mesenchymal cells, has the binding partners Axl expressed by dormant myeloma cells, Mertk in dormant breast cancer cells and Mertk and Tyro3 in dormant prostate cancer. Treatment of mice bearing myeloma cells with small molecule inhibitors of Axl reduced dormant cells and increased tumor burden suggesting the Axl/Gas6 interaction is functional important in controlling dormancy. Together these data show that single cell sequencing can be used to define the cells and molecular pathways that facilitate dormant cancer cell niche formation in the skeleton. This approach suggests that that cancer cell specific molecules interact with common molecules in the endosteal niche, including LeprHigh/Cxcl12High mesenchymal cells, to switch on common molecular pathways to control dormancy. Citation Format: Peter Croucher, Weng Hua Khoo, Ryan Chai, Alex Corr, James Smith, Qihao Ren, Paul Baldock, Michelle McDonald, Sheila Stewart, Tri G. Phan. Niche-dependent control of tumor cell dormancy [abstract]. In: Proceedings of the AACR Virtual Special Conference on the Evolving Tumor Microenvironment in Cancer Progression: Mechanisms and Emerging Therapeutic Opportunities; in association with the Tumor Microenvironment (TME) Working Group; 2021 Jan 11-12. Philadelphia (PA): AACR; Cancer Res 2021;81(5 Suppl):Abstract nr IA015.

Simple SummaryOverall survival of patients with cancer is dependent on the success of therapy. Therapy failure is correlated with enhanced metastasis and recurrence of the primary tumor. However, metastases may develop before the detection of a primary tumor and become dormant at their secondary site, presenting a major clinical challenge as these dormant cells can reactivate after the completion of seemingly successful therapy. Research has demonstrated that the innate immune system plays an integral role in molecular crosstalk with cancer cells to facilitate metastatic dissemination and control over a dormant cell state. Here, we discuss which types of innate immune cells are engaged in this crosstalk at each stage of the metastatic cascade. We also highlight how different subtypes of innate immune cells induce dormancy in cancer cells and facilitate the emergence from a dormant state. Lastly, we examine current therapeutic strategies aimed at inhibiting immune-mediated metastasis and dormancy.Metastatic spread and recurrence are intimately linked to therapy failure, which remains an overarching clinical challenge for patients with cancer. Cancer cells often disseminate early in the disease process and can remain dormant for years or decades before re-emerging as metastatic disease, often after successful treatment. The interactions of dormant cancer cells and their metastatic niche, comprised of various stromal and immune cells, can determine the length of time that cancer cells remain dormant, as well as when they reactivate. New studies are defining how innate immune cells in the primary tumor may be corrupted to help facilitate many aspects of dissemination and re-emergence from a dormant state. Although the scientific literature has partially shed light on the drivers of immune escape in cancer, the specific mechanisms regulating metastasis and dormancy in the context of anti-tumor immunity are still mostly unknown. This review follows the journey of metastatic cells from dissemination to dormancy and the onset of metastatic outgrowth and recurrent tumor development, with emphasis on the role of the innate immune system. To this end, further research identifying how immune cells interact with cancer cells at each step of cancer progression will pave the way for new therapies that target the reactivation of dormant cancer cells into recurrent, metastatic cancers.

Cancer recurrence resulting from the metastatic outbreak of dormant disseminated tumor cells following the apparent successful treatment of the primary tumor is a major cause of breast cancer mortality. However, little is known regarding the molecular mechanisms governing tumour cell dormancy and the dormant-to-proliferative switch, impeding the development of effective therapeutic strategies. We therefore investigated whether stress-induced autophagy may promote survival of dormant cancer cells and, consequently, inhibition of autophagy could prevent breast cancer recurrence. To address the functional role of autophagy in breast cancer progression and the potential therapeutic impact of its inhibition, we utilized mouse and human 3D in vitro and in vivo preclinical models of dormancy. The analysis of autophagy markers and use of an autophagic flux biosensor allowed direct visualization of autophagic vesicles and their evolution in breast cancer dormant cells over time. In agreement with our hypothesis, pharmacologic or genetic inhibition of autophagy in dormant breast cancer cells resulted in significantly decreased cell survival and metastatic burden in vitro and in vivo. Furthermore, the inhibition of autophagy prevented the spontaneous dormant-to-proliferative switch of highly metastatic cells. In contrast, proliferating disseminated cells were insensitive to autophagy blockade. Indeed, in vivo analysis of the autophagic flux over time confirmed that autophagy is a critical survival process activated and maintained in dormant breast cancer cells, which is shut down after the cells undergo the dormant-to-proliferative switch. Transcriptomic analysis and in vivo metastatic burden assays identified the autophagy-related 7 (ATG7) gene, but not Beclin1 (BECN1), to be essential for autophagy activation, indicating that a non-canonical autophagy pathway is activated in dormant breast cancer cells. Co-localization studies identified mitochondria as the predominant autophagosomal cargo in breast cancer dormant cells. Mechanistically, inhibition of the autophagic flux in dormant breast cancer cells led to the accumulation of depolarized mitochondria and reactive oxygen species (ROS), resulting in cell apoptosis. This study has important implications regarding the role of autophagy in breast cancer progression and suggests that inhibition of autophagy may be of therapeutic value in preventing breast cancer recurrence. Furthermore, it provides novel insights into the molecular mechanisms for survival of breast cancer dormant cells. Citation Format: Laura Vera Ramirez, Suman K. Vodnala, Ryan Nini, Kent W. Hunter, Jeffrey E. Green. Survival of dormant breast cancer cells and metastatic tumor recurrence is dependent upon the activation of autophagy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 57.

Highlights from Recent Cancer Literature

Lung cancer is the leading cause of cancer-related deaths worldwide. Chemotherapy kills most cancer cells; however, residual cells enter a dormant state. The dormant cancer cells can be reactivated under specific circumstances. The "premetastatic niche" that is suitable for colonization of cancer cells is formed before the arrival of cancer cells. Tumor-derived exosomes are the main mediators of tumorigenesis. We are aiming to elucidate the roles of exosomes from cisplatin-induced dormant lung cancer cells in the formation of premetastatic niches in bone marrow. We performed differential proteomics in dormant A549 cell- and A549 cell-derived exosomes. Non-targeted metabolomics and RNA sequencing were performed to explore the molecular and metabolic reprogramming of bone marrow stromal cells (BMSCs). The growth and metastasis of A549 cells in vivo were monitored by bioluminescence imaging. We found that Insulin-like growth factor 2 (IGF-2) and Insulin-like growth factor binding protein 2 (IGFBP2) were upregulated in dormant A549 cell-derived exosomes. BMSCs that took up exosomes from dormant A549 cells showed enhanced glycolysis and promoted the growth and metastasis of A549 cells possibly through Insulin-like growth factor 1 receptor (IGF-1R)-induced metabolic reprogramming. Inhibition of the production of lactate and IGF-1R signaling can suppress the growth and metastasis of A549 cells from bone marrow. Overall, we demonstrated that BMSCs formed a premetastatic niche upon taking up exosomes from cisplatin-induced dormant lung cancer cells. BMSCs promoted lung cancer cell growth and metastasis through the reverse Warburg effect.

Although autologous fat grafting is considered a successful method for the management of contour deformities, the fat graft could potentially induce cancer reappearance by fueling dormant breast cancer cells. Our aim was to characterize the role of adipose-derived stem cells on active and dormant breast cancer cell growth. Cobalt chloride was used to induce dormancy in MCF-7 cancer cells. Proliferation of active and dormant cancer cells was determined in the presence of adipose-derived stem cells. A proteome array was used to detect cancer-related protein expression in the cell-conditioned medium. The migration of cancer cells was measured in response to conditioned medium from the adipose-derived stem cells. The adipose-derived stem cells showed variable effects on active MCF-7 cells growth and inhibited MCF-7 proliferation after the withdrawal of cobalt chloride. Of the 84 different proteins measured in the conditioned medium, only tenascin-C was differentially expressed in the co-cultures. MCF-7 cells alone did not express tenascin-C, whereas co-cultures between MCF-7 and adipose-derived stem cells expressed more tenascin-C versus adipose-derived stem cells alone. The conditioned medium from co-cultures significantly increased the migration of the cancer cells. Adipose-derived stem cells themselves neither increased the growth or migration of cancer cells, suggesting that autologous fat grafting may be oncologically safe if reconstruction is postponed until there is no evidence of active disease. However, interactions between adipose-derived stem cells and MCF-7 cancer cells could potentially lead to the production of factors, which further promote cancer cell migration.

The discovery of anticancer therapeutics effective in eliminating dormant cells is a significant challenge in cancer biology. Here, we describe new synthetic polymer-based anticancer agents that mimic the mode of action of anticancer peptides. These anticancer polymers developed here are designed to capture the cationic, amphiphilic traits of anticancer peptides. The anticancer polymers are designed to target anionic lipids exposed on the cancer cell surfaces and act by disrupting the cancer cell membranes. Because the polymer mechanism is not dependent on cell proliferation, we hypothesized that the polymers were active against dormant cancer cells. The polymers exhibited cytotoxicity to proliferating prostate cancer. Importantly, the polymer killed dormant prostate cancer cells that were resistant to docetaxel. This study demonstrates a new approach to discover novel anticancer therapeutics.

Breast cancer cells can respond to microenvironmental stressors by becoming dormant, that is inhibiting cell proliferation until the environment becomes growth-permissive. One of the survival pathways implicated in dormant cancer cells is the p38MAPK pathway. Modulation of signaling to combat metabolic stressors could provide survival benefits to dormant breast cancer cells. AMPK (AMP-activated protein kinase) is the central metabolic regulator of the cell, and its expression is altered in breast cancer. Moreover, there are two isoforms of the catalytic subunit (α1 and α2), and differential functionality of these isoforms has been reported. Using estrogen-receptor positive human breast cancer cell lines, we investigated the effect of differential AMPKα isoform expression on breast cancer survival. We found that over-expression of AMPKα2 in MCF-7 cells resulted in stronger p38MAPK activation in response to chemical AMPK activation or metabolic stress. Moreover, the same signaling was observed in HCC1500 cells, which endogenously express AMPKα2. Additionally, we cultured our cell lines as spheroids in order to mimic a tumor microenvironment. MCF-7 AMPKα2 cells formed larger, more viable spheres than control cells. In addition, the expression of AMPKα2 facilitated spheroid survival under hypoxic conditions. Finally, activation of p38MAPK was seen most abundantly in the MCF-7 AMPKα2 spheres. Our in vitro studies indicate an AMPKα2-dependent regulation of p38MAPK in response to metabolic stress in order to promote cancer cell survival. To evaluate cancer dormancy in vivo, MCF-7 cells expressing either GFP or AMPKα2 were injected into athymic nude mice previously implanted with slow-release estradiol pellets. After one week, the estradiol pellets were removed to induce cellular dormancy for thirty days. Analysis of tumors at this time indicated that more of the AMPKα2 expressing cells survived estradiol deprivation than did the control cells. Analysis of proliferation by Ki67 staining indicated that the GFP cells maintained proliferation during deprivation, while AMPKα2 cells were largely negative for proliferation. ApoTag staining revealed a similar trend for apoptotic cells. This suggests an inability to control cell cycle resulted in a decreased survival of the GFP cells under estradiol deprivation. Consistent with our observed in vitro cell signaling, AMPKα2 expressing tumors expressed higher levels of phospho-p38MAPK than GFP expressing tumors. Following the deprivation period, estradiol pellets were re-implanted and residual dormant tumors resumed growth. AMPKα2 tumors grew to roughly double the size of GFP tumors. Interestingly, AMPKα2 tumors had a higher number of mitotic events than did GFP tumors as visualized by Ki67 staining. This could be due to more viable cells being present following estradiol deprivation. We conclude that the expression of AMPKα2 promotes long-term breast cancer survival in estrogen-sensitive cells. Citation Format: Katie L. Sullivan, Stavros Kopsiaftis, Kathryn N. Phoenix, Melissa M. Fox, Kevin P. Claffey. AMPK promotes survival of breast cancer cells by modulating metabolic stress. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1138. doi:10.1158/1538-7445.AM2015-1138

Cancer cell dormancy is a common feature of human tumors and represents a major clinical barrier to the long-term efficacy of anticancer therapies. Dormant cancer cells, either in primary tumors or disseminated in secondary organs, may reawaken and relapse into a more aggressive disease. The mechanisms underpinning dormancy entry and exit strongly resemble those governing cancer cell stemness and include intrinsic and contextual cues. Cellular and molecular components of the tumor microenvironment persistently interact with cancer cells. This dialog is highly dynamic, as it evolves over time and space, strongly cooperates with intrinsic cell nets, and governs cancer cell features (like quiescence and stemness) and fate (survival and outgrowth). Therefore, there is a need for deeper insight into the biology of dormant cancer (stem) cells and the mechanisms regulating the equilibrium quiescence-versus-proliferation are vital in our pursuit of new therapeutic opportunities to prevent cancer from recurring. Here, we review and discuss microenvironmental regulations of cancer dormancy and its parallels with cancer stemness, and offer insights into the therapeutic strategies adopted to prevent a lethal recurrence, by either eradicating resident dormant cancer (stem) cells or maintaining them in a dormant state.

Breast cancer is the most common form of cancer and the second cancer-causing death in females. Although remission rates are high if detected early, survival rates drop substantially when breast cancer becomes metastatic. Metastatic relapse can occur months to years after the initial diagnosis and treatment of the primary tumor. This relapse is mediated by awakening of dormant disseminated cancer cells (dDCCs). Studies have demonstrated that the relationship between the microenvironment and dDCCs is critical for maintaining both dormancy and for facilitating awakening to promote metastasis development. Prior studies have shown increased inflammation in the microenvironment can facilitate DCC awakening and outgrowth. Viral respiratory infections are also associated with massive inflammation and immune cell influx, typically in acute form. Respiratory infections affect millions of people worldwide, as is particularly evident in the ongoing SARS-CoV2 pandemic and variably severe annual influenza seasons. How the inflammatory response to viral respiratory infections impacts breast cancer metastasis remains unclear. Using FVB MMTV-erbB2/neu/HER2 mice as a model of breast dormancy in the lungs and influenza virus, we show that following influenza infection there is a significant increase in the number of disseminated cancer cells in the lungs of influenza infected mice with more than a 1000-fold expansion of carcinoma cells over a couple of weeks. Interestingly most of this expansion of DCCs takes place within 10 days following influenza infection. Strikingly, by 15 days post-infection, the lesions that expanded from solitary HER2+ DCCs almost homogeneously return to a quiescent state. Furthermore, we show interleukin-6 is required for the early phase of dormant cancer cells reawakening and proliferation and that CD4+ T cells are required for the maintenance of the expanded cancer cells post-infection at the late phase. Depletion of CD4 T cells (but not CD8 cells) during infection with influenza virus leads to the elimination of the expanded DCC population in the lung. Finally, single-cell RNA-seq analyses of DCC and microenvironmental cells in the lungs before and after infection reveals insight into underlying mechanisms for virus-induced awakening and reentry into dormancy. scRNA-seq analyses reveal that expanding DCC post-influenza infection reprogram CD4 and CD8 T-cells to a more immune suppressed state. These results support a model whereby pulmonary viral infections can increase the risk of metastatic relapse in the lungs for patients with a prior history of breast cancer. Thus, the immune response evolved to combat respiratory infections can be coopted and reprogrammed by dormant cancer cells to enable their expansion, thus increasing the odds of further metastatic cancer evolution. Ongoing work is currently being done to investigate this process in mouse models of SARS-CoV2 infection, as well as to examine clinical databases for epidemiological associations between respiratory viral infections and metastatic disease in the lung. Citation Format: Bryan J. Johnson, Shi Biao Chia, Vadym Zaberezhnyy, Varsha Sreekanth, Meher Boorgula, Michael Papanicolaou, James Costello, Andrew Goodspeed, Julio A. Aguirre-Ghiso, Mercedes Rincon, James V. DeGregori. Influenza-induced inflammatory response reactivates and promotes dormant breast cancer cell outgrowth in lungs [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Translating Cancer Evolution and Data Science: The Next Frontier; 2023 Dec 3-6; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(3 Suppl_2):Abstract nr B021.

<div>Abstract<p>Dormant cancer cells that survive anticancer therapy can lead to cancer recurrence and disseminated metastases that prove fatal in most cases. Recently, specific dormant polyploid giant cancer cells (PGCC) have drawn our attention because of their association with the clinical risk of nasopharyngeal carcinoma (NPC) recurrence, as demonstrated by previous clinical data. In this study, we report the biological properties of PGCC, including mitochondrial alterations, and reveal that autophagy is a critical mechanism of PGCC induction. Moreover, pharmacologic or genetic inhibition of autophagy greatly impaired PGCC formation, significantly suppressing metastasis and improving survival in a mouse model. Mechanistically, chemotherapeutic drugs partly damaged mitochondria, which then produced low ATP levels and activated autophagy via the AMPK-mTOR pathway to promote PGCC formation. Analysis of the transcriptional and epigenetic landscape of PGCC revealed overexpression of RIPK1, and the scaffolding function of RIPK1 was required for AMPK-mTOR pathway-induced PGCC survival. High numbers of PGCCs correlated with shorter recurrence time and worse survival outcomes in patients with NPC. Collectively, these findings suggest a therapeutic approach of targeting dormant PGCCs in cancer.</p>Significance:<p>Pretreatment with an autophagy inhibitor before chemotherapy could prevent formation of therapy-induced dormant polyploid giant cancer cells, thereby reducing recurrence and metastasis of nasopharyngeal carcinoma.</p></div>

<div>Abstract<p>Dormant cancer cells that survive anticancer therapy can lead to cancer recurrence and disseminated metastases that prove fatal in most cases. Recently, specific dormant polyploid giant cancer cells (PGCC) have drawn our attention because of their association with the clinical risk of nasopharyngeal carcinoma (NPC) recurrence, as demonstrated by previous clinical data. In this study, we report the biological properties of PGCC, including mitochondrial alterations, and reveal that autophagy is a critical mechanism of PGCC induction. Moreover, pharmacologic or genetic inhibition of autophagy greatly impaired PGCC formation, significantly suppressing metastasis and improving survival in a mouse model. Mechanistically, chemotherapeutic drugs partly damaged mitochondria, which then produced low ATP levels and activated autophagy via the AMPK-mTOR pathway to promote PGCC formation. Analysis of the transcriptional and epigenetic landscape of PGCC revealed overexpression of RIPK1, and the scaffolding function of RIPK1 was required for AMPK-mTOR pathway-induced PGCC survival. High numbers of PGCCs correlated with shorter recurrence time and worse survival outcomes in patients with NPC. Collectively, these findings suggest a therapeutic approach of targeting dormant PGCCs in cancer.</p>Significance:<p>Pretreatment with an autophagy inhibitor before chemotherapy could prevent formation of therapy-induced dormant polyploid giant cancer cells, thereby reducing recurrence and metastasis of nasopharyngeal carcinoma.</p></div>

The awakening of dormant disseminated cancer cells is likely responsible for the clinical relapses of patients whose primary tumors have been cured months and even years earlier. In the present study, we demonstrate that dormant breast cancer cells lodged in the lungs reside in a highly mesenchymal, non-proliferative phenotypic state. The awakening of these cells does not occur by a cancer cell-autonomous process. Instead, inflammation and wound healing of the surrounding tissue microenvironment causes them to shift from a highly mesenchymal to a quasi-mesenchymal phenotypic state in which they acquire stemness and proliferative ability. Once awakened, these cells can stably reside in this quasi-mesenchymal state and maintain their stemness, doing so without ongoing heterotypic signaling from the lung microenvironment. EGFR ligands released by the cells of the injured tissue microenvironment, including notably M2 type macrophages, promote dormant cancer cells to move toward this quasi-mesenchymal state, a transition that is essential for the awakening process. An understanding of the mechanisms of metastatic awakening may lead in the future to treatment strategies designed to prevent such awakening and resulting metastatic relapse. Citation Format: Jingwei Zhang, Robert Weinberg. Awakened dormant cancer cells undergo highly mesenchymal to quasi- mesenchymal transition and acquire stemness [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C018.

The awakening of dormant disseminated cancer cells appears to be responsible for the clinical relapses of patients whose primary tumors have been successfully cured months and even years earlier. In the present study, we demonstrate that dormant breast cancer cells lodged in the lungs reside in a highly mesenchymal, nonproliferative phenotypic state. The awakening of these cells is not triggered by a cancer cell-autonomous process. Instead, lung inflammation induced by the chemotherapeutic agent bleomycin effectively awakens dormant cancer cells, providing useful models for studying metastatic awakening. Mechanistically, the awakened cells shift from a highly mesenchymal to a quasi-mesenchymal phenotypic state in which they acquire tumorigenicity and proliferative ability. Once awakened, these cells can stably reside in this quasi-mesenchymal state and maintain their tumor-initiating ability, doing so without ongoing heterotypic signaling from the lung microenvironment. Epidermal growth factor receptor ligands released by the cells of the injured tissue microenvironment, including notably M2 type macrophages, promote dormant cancer cells to move toward this quasi-mesenchymal state, a transition that is critical for the awakening process. An understanding of the mechanisms of metastatic awakening may lead in the future to treatment strategies designed to prevent such awakening and resulting metastatic relapse.

The awakening of dormant disseminated cancer cells is likely responsible for the clinical relapses of patients whose primary tumors have been successfully cured months and even years earlier. In the present study, we demonstrate that dormant breast cancer cells lodged in the lungs reside in a highly mesenchymal, non-proliferative phenotypic state. The awakening of these cells is not triggered by a cancer cell-autonomous process. Instead, inflammation of the surrounding tissue microenvironment causes them to shift from a highly mesenchymal to a quasi-mesenchymal phenotypic state in which they acquire stemness and proliferative ability. Once awakened, these cells can stably reside in this quasi-mesenchymal state and maintain their stemness, doing so without ongoing heterotypic signaling from the lung microenvironment. EGFR ligands released by the cells of the injured tissue microenvironment, including notably M2 type macrophages, promote dormant cancer cells to move toward this quasi-mesenchymal state, a transition that is critical for the awakening process. An understanding of the mechanisms of metastatic awakening may lead in the future to treatment strategies designed to prevent such awakening and resulting metastatic relapse. Citation Format: Jingwei Zhang, Robert Allan Weinberg. Awakened dormant cancer cells undergo highly mesenchymal to quasi-mesenchymal transition and acquire stemness [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 3826.