NOXA-dependent contextual synthetic lethality of BCL-XL inhibition and “osmotic reprogramming” in colorectal cancer

A sophisticated network of BCL-2 family proteins regulates the mitochondria-associated (intrinsic) apoptosis pathway. Antiapoptotic members such as BCL-XL or MCL-1 safeguard the outer mitochondrial membrane and prevent accidental cell death in a functionally redundant and/or compensatory manner. However, BCL-XL/MCL-1-mediated "dual apoptosis protection" also impairs response of cancer cells to chemotherapy. Here, we show that hyperosmotic stress in the tumor environment abrogates dual BCL-XL/MCL-1 protection. Hypertonicity triggers upregulation of NOXA and loss of MCL-1 and thereby enforces exclusive BCL-XL addiction. Concomitant targeting of BCL-XL is sufficient to unlock the intrinsic apoptosis pathway in colorectal cancer cells. Functionally, "osmotic reprogramming" of the tumor environment grants contextual synthetic lethality to BCL-XL inhibitors in dually BCL-XL/MCL-1-protected cells. Generation of contextual synthetic lethality through modulation of the tumor environment could perspectively boost efficacy of anticancer drugs

Pre-existing subclones determine radioresistance in rectal cancer organoids

More than half of all patients with cancer receive radiation therapy, but resistance is commonly observed. Currently, it is unknown whether resistance to radiation therapy is acquired or inherently present. Here, we employed organoids derived from rectal cancer and single-cell whole-genome sequencing to investigate the long-term evolution of subclones in response to radiation. Comparing single-cell whole-genome karyotypes between in-vitro-unirradiated and -irradiated organoids revealed three patterns of subclonal evolution: (1) subclonal persistence, (2) subclonal extinction, and (3) subclonal expansion. Organoids in which subclonal shifts occurred (i.e., expansion or extinction) became more resistant to radiation. Although radioresistant subclones did not share recurrent copy-number alterations that could explain their radioresistance, resistance was associated with reduced chromosomal instability, an association that was also observed in 529 human cancer cell lines. These data suggest that resistance to radiation is inherently present and associated with reduced chromosomal instability

In vitro chemotherapy-associated muscle toxicity is attenuated with nutritional support, while treatment efficacy is retained.

PURPOSE: Muscle-wasting and treatment-related toxicities negatively impact prognosis of colorectal cancer (CRC) patients. Specific nutritional composition might support skeletal muscle and enhance treatment support. In this in vitro study we assess the effect of nutrients EPA, DHA, L-leucine and vitamin D3, as single nutrients or in combination on chemotherapy-treated C2C12-myotubes, and specific CRC-tumor cells. MATERIALS AND METHODS: Using C2C12-myotubes, the effects of chemotherapy (oxaliplatin, 5-fluorouracil, oxaliplatin+5-fluorouracil and irinotecan) on protein synthesis, cell-viability, caspase-3/7-activity and LDH-activity were assessed. Addition of EPA, DHA, L-leucine and vitamin D3 and their combination (SNCi) were studied in presence of above chemotherapies. Tumor cell-viability was assessed in oxaliplatin-treated C26 and MC38 CRC cells, and in murine and patient-derived CRC-organoids. RESULTS: While chemotherapy treatment of C2C12-myotubes decreased protein synthesis, cell-viability and increased caspase-3/7 and LDH-activity, SNCi showed improved protein synthesis and cell viability and lowered LDH activity. The nutrient combination SNCi showed a better overall performance compared to the single nutrients. Treatment response of tumor models was not significantly affected by addition of nutrients. CONCLUSIONS: This in vitro study shows protective effect with specific nutrition composition of C2C12-myotubes against chemotherapy toxicity, which is superior to the single nutrients, while treatment response of tumor cells remained

Specialized nutrition improves muscle function and physical activity without affecting chemotherapy efficacy in C26 tumour-bearing mice

Background: Skeletal muscle wasting and fatigue are commonly observed in cancer patients receiving chemotherapy and associated with reduced treatment outcome and quality of life. Nutritional support may mitigate these side effects, but potential interference with chemotherapy efficacy could be of concern. Here, we investigated the effects of an ω-3 polyunsaturated fatty acid (eicosapentaenoic acid and docosahexaenoic acid), leucine-enriched, high-protein (100% whey), additional vitamin D, and prebiotic fibres ‘specific nutritional composition’ (SNC) and chemotherapy on state-of-the-art tumour organoids and muscle cells and studied muscle function, physical activity, systemic inflammation, and chemotherapy efficacy in a mouse model of aggressive colorectal cancer (CRC). Methods: Tumour-bearing mice received a diet with or without SNC. Chemotherapy treatment consisted of oxaliplatin and 5-fluorouracil. Tumour formation was monitored by calliper measurements. Physical activity was continuously monitored by infrared imaging. Ex vivo muscle performance was determined by myography, muscle fatty acid composition by gas chromatography, and plasma cytokine levels by Luminex xMAP technology. Patient-derived CRC organoids and C2C12 myotubes were used to determine whether SNC affects chemotherapy sensitivity in vitro. Results: Specific nutritional composition increased muscle contraction capacity of chemotherapy-treated tumour-bearing mice (P < 0.05) and enriched ω-3 fatty acid composition in muscle without affecting treatment efficacy (P < 0.0001). Mice receiving SNC maintained physical activity after chemotherapy and showed decreased systemic inflammation. Therapeutic response of CRC organoids was unaffected by SNC nutrients, while cell viability and protein synthesis of muscle cells significantly improved. Conclusions: The results show that specialized nutritional support can be used to maintain muscle function and physical activity levels during chemotherapy without increasing tumour viability. Therefore, nutritional strategies have potential value in promoting cancer and chemotherapy tolerance

Pre-existing subclones determine radioresistance in rectal cancer organoids

More than half of all patients with cancer receive radiation therapy, but resistance is commonly observed. Currently, it is unknown whether resistance to radiation therapy is acquired or inherently present. Here, we employed organoids derived from rectal cancer and single-cell whole-genome sequencing to investigate the long-term evolution of subclones in response to radiation. Comparing single-cell whole-genome karyotypes between in-vitro-unirradiated and -irradiated organoids revealed three patterns of subclonal evolution: (1) subclonal persistence, (2) subclonal extinction, and (3) subclonal expansion. Organoids in which subclonal shifts occurred (i.e., expansion or extinction) became more resistant to radiation. Although radioresistant subclones did not share recurrent copy-number alterations that could explain their radioresistance, resistance was associated with reduced chromosomal instability, an association that was also observed in 529 human cancer cell lines. These data suggest that resistance to radiation is inherently present and associated with reduced chromosomal instability

Onward Spread from Liver Metastases Is a Major Cause of Multi-Organ Metastasis in a Mouse Model of Metastatic Colon Cancer

Colorectal cancer metastasizes predominantly to the liver but also to the lungs and the peritoneum. The presence of extra-hepatic metastases limits curative (surgical) treatment options and is associated with very poor survival. The mechanisms governing multi-organ metastasis formation are incompletely understood. Here, we tested the hypothesis that the site of tumor growth influences extra-hepatic metastasis formation. To this end, we implanted murine colon cancer organoids into the primary tumor site (i.e., the caecum) and into the primary metastasis site (i.e., the liver) in immunocompetent mice. The organoid-initiated liver tumors were significantly more efficient in seeding distant metastases compared to tumors of the same origin growing in the caecum (intra-hepatic: 51 vs. 40%, p = 0.001; peritoneal cavity: 51% vs. 33%, p = 0.001; lungs: 30% vs. 7%, p = 0.017). The enhanced metastatic capacity of the liver tumors was associated with the formation of 'hotspots' of vitronectin-positive blood vessels surrounded by macrophages. RNA sequencing analysis of clinical samples showed a high expression of vitronectin in liver metastases, along with signatures reflecting hypoxia, angiogenesis, coagulation, and macrophages. We conclude that 'onward spread' from liver metastases is facilitated by liver-specific microenvironmental signals that cause the formation of macrophage-associated vascular hotspots. The therapeutic targeting of these signals may help to contain the disease within the liver and prevent onward spread

Metabolic Syndrome at an Outpatient Clinic for Bipolar Disorders:A Case for Systematic Somatic Monitoring

OBJECTIVES:: The primary objective of the study was to determine whether the Monitoring Outcomes of Psychiatric Pharmacotherapy (MOPHAR) program improved somatic monitoring practices at an outpatient clinic for bipolar disorders in the Netherlands. The secondary objective was to determine in MOPHAR the frequency of metabolic syndrome (compared with its measurability before MOPHAR) and treatment thereof. METHODS:: Frequencies of physical examinations and laboratory tests before (retrospectively) and after (prospectively) the active introduction of MOPHAR were compared among adult patients (N=155). RESULTS:: A median of three measurements (range 0-19) per patient were performed before MOPHAR, compared with 24 measurements (range 3-24) after MOPHAR (p<0.001). MOPHAR revealed somatic abnormalities previously unknown to treating physicians. Metabolic syndrome was present in 53% of patients; of these, 98% were not known to have metabolic syndrome before MOPHAR. CONCLUSIONS:: Introducing a monitoring program largely improved knowledge regarding metabolic abnormalities, which are frequently present among patients with bipolar disorder

Differential anti-tumour effects of MTH1 inhibitors in patient-derived 3D colorectal cancer cultures

Reactive oxygen species (ROS) function as second messengers in signal transduction, but high ROS levels can also cause cell death. MTH1 dephosphorylates oxidized nucleotides, thereby preventing their incorporation into DNA and protecting tumour cells from oxidative DNA damage. Inhibitors of MTH1 (TH588 and (S)-crizotinib) were shown to reduce cancer cell viability. However, the MTH1-dependency of the anti-cancer effects of these drugs has recently been questioned. Here, we have assessed anti-tumour effects of TH588 and (S)-crizotinib in patient-derived 3D colorectal cancer cultures. Hypoxia and reoxygenation - conditions that increase intracellular ROS levels - increased sensitivity to (S)-crizotinib, but not to TH588. (S)-crizotinib reduced tyrosine phosphorylation of c-MET and ErbB3 whereas TH588 induced a mitotic cell cycle arrest, which was not affected by adding ROS-modulating compounds. Furthermore, we show that both compounds induced DNA damage that could not be prevented by adding the ROS inhibitor N-acetyl-L-cysteine. Moreover, adding ROS-modulating compounds did not alter the reduction in viability in response to TH588 and (S)-crizotinib. We conclude that TH588 and (S)-crizotinib have very clear and distinct anti-tumour effects in 3D colorectal cancer cultures, but that these effects most likely occur through distinct and ROS-independent mechanisms