Periodic Reporting for period 2 - TUMOR-LOCK (Tumor-lock: forbid the generation of circulating tumor cells)
Berichtszeitraum: 2022-12-01 bis 2024-05-31
No therapies are currently designed with the goal to prevent the spread of cancer. Rather, the general aim is to kill cancer cells, which may delay but not prevent metastasis formation, mostly due to the emergence of drug-resistant clones that are positively selected during a tumor-killing approach. Mechanisms that promote the spread of breast cancer cells have been investigated, yet, surprisingly, little is known about the molecular events that dictate their entry into the bloodstream (a.k.a. intravasation) and as a consequence, no anti-metastasis therapeutic approaches have emerged. Our project aims to go far beyond standard approaches, and identify a non-tumor-killing approach that selectively impairs
the entry of tumor cells into the circulation, thereby locking tumor cells in situ while avoiding selection for drug-resistant clones. We envision our “tumor-lock” strategy to be compatible with simultaneous administration of standard-of-care therapies during tumor progression, and to benefit patients at virtually all stages, i.e. suppressing both primary-to-metastasis and metastasis-to-metastasis cascading dissemination.
We hypothesize that our approach will lead to the identification of new targets, whose inhibition will blunt the ability of cancer cells to intravasate, resulting in metastasis prevention. Our Aims are specifically designed to test this hypothesis.
Particularly: in Aim 1 we will identify fundamental mechanisms governing CTC generation. This will include investigations of the tumor microenvironment, transcriptomic, genomic and epigenomic patterns, the circadian rhythm and the immune system. In Aim 2 we will identify actionable targets and treatment opportunities. This will include CRISPR-based genetic engineering and target identification, as well as phenotypic drug screens.
the entry of tumor cells into the circulation, thereby locking tumor cells in situ while avoiding selection for drug-resistant clones. We envision our “tumor-lock” strategy to be compatible with simultaneous administration of standard-of-care therapies during tumor progression, and to benefit patients at virtually all stages, i.e. suppressing both primary-to-metastasis and metastasis-to-metastasis cascading dissemination.
We hypothesize that our approach will lead to the identification of new targets, whose inhibition will blunt the ability of cancer cells to intravasate, resulting in metastasis prevention. Our Aims are specifically designed to test this hypothesis.
Particularly: in Aim 1 we will identify fundamental mechanisms governing CTC generation. This will include investigations of the tumor microenvironment, transcriptomic, genomic and epigenomic patterns, the circadian rhythm and the immune system. In Aim 2 we will identify actionable targets and treatment opportunities. This will include CRISPR-based genetic engineering and target identification, as well as phenotypic drug screens.
We have found that the circadian rhythm strongly affects CTC generation dynamics. (Diamantopoulou et al., Nature, 2022)
Summary:
The metastatic spread of cancer is achieved by the hematogenous dissemination of circulating tumor cells (CTCs). Generally, however, the temporal dynamics that dictate the generation of metastasis-competent CTCs are largely uncharacterized, often assuming that CTCs are constantly shed from growing tumors or shed as a consequence of mechanical insults. In this study, we have observed a striking and unexpected pattern of CTC generation dynamics in both patients with breast cancer and mouse models, highlighting that the vast majority of spontaneous CTC intravasation events occur during the rest phase. Further, we demonstrated that rest-phase CTCs are highly metastasis-prone, while CTCs generated during active phase are devoid of metastatic ability. Mechanistically, single cell-resolution RNA sequencing analysis of CTCs revealed a dramatic upregulation of mitotic genes exclusively during the rest phase in both patients and mouse models, enabling metastasis proficiency. Mechanistically, we found that key circadian rhythm hormones such as melatonin, testosterone and glucocorticoids dictate CTC generation dynamics, and as a consequence, that insulin directly promotes tumor cell proliferation in vivo, yet in a time-dependent manner. Thus, the spontaneous generation of CTCs with a high proclivity to metastasize does not occur continuously but it is concentrated within the rest phase of the host, providing a new rationale for time-controlled interrogation and treatment of metastasis-prone cancers.
Additional investigations related to the tumor microenvironment, transcriptomic, genomic and epigenomic patterns, as well as the immune system are ongoing.
Summary:
The metastatic spread of cancer is achieved by the hematogenous dissemination of circulating tumor cells (CTCs). Generally, however, the temporal dynamics that dictate the generation of metastasis-competent CTCs are largely uncharacterized, often assuming that CTCs are constantly shed from growing tumors or shed as a consequence of mechanical insults. In this study, we have observed a striking and unexpected pattern of CTC generation dynamics in both patients with breast cancer and mouse models, highlighting that the vast majority of spontaneous CTC intravasation events occur during the rest phase. Further, we demonstrated that rest-phase CTCs are highly metastasis-prone, while CTCs generated during active phase are devoid of metastatic ability. Mechanistically, single cell-resolution RNA sequencing analysis of CTCs revealed a dramatic upregulation of mitotic genes exclusively during the rest phase in both patients and mouse models, enabling metastasis proficiency. Mechanistically, we found that key circadian rhythm hormones such as melatonin, testosterone and glucocorticoids dictate CTC generation dynamics, and as a consequence, that insulin directly promotes tumor cell proliferation in vivo, yet in a time-dependent manner. Thus, the spontaneous generation of CTCs with a high proclivity to metastasize does not occur continuously but it is concentrated within the rest phase of the host, providing a new rationale for time-controlled interrogation and treatment of metastasis-prone cancers.
Additional investigations related to the tumor microenvironment, transcriptomic, genomic and epigenomic patterns, as well as the immune system are ongoing.
Our discovery that CTC dynamics are regulated by the circadian rhythm (Diamantopoulou et al., Nature, 2022) has opened completely new avenues for the development of new therapeutic strategies in breast cancer. These include time-of-day driven diagnostic and therapeutic approaches that will need to be tested in future clinical studies. We expect additional exciting data to be generated until the end of the project and including investigations of the tumor microenvironment, transcriptomic, genomic and epigenomic patterns, as well as the immune system and how these aspects shape CTC intravasation dynamics.