Global metabolic alterations in colorectal cancer cells during irinotecan-induced DNA replication stress

Study on the effects of rapamycin and the mTORC1/2 dual inhibitor OSI-027 on the metabolism of colon cancer cells based on UPLC-MS/MS metabolomics

mTORC1/2 dual inhibitors may be more effective than mTORC1 inhibitor rapamycin. However, their metabolic impacts on colon cancer cells remain unexplored. We conducted a comparative analysis of the anti-proliferative effects of rapamycin and the novel OSI-027 in colon cancer cells HCT-116, evaluating their metabolic influences through ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS/MS). Our results demonstrate that OSI-027 more effectively inhibits colon cancer cell proliferation than rapamycin. Additionally, we identified nearly 600 metabolites from the spectra, revealing significant differences in metabolic patterns between cells treated with OSI-027 and rapamycin. Through VIP value screening, we pinpointed crucial metabolites contributing to these distinctions. For inhibiting glycolysis and reducing glucose consumption, OSI-027 was likely to be more potent than rapamycin. For amino acids metabolism, although OSI-027 has a broad effect as rapamycin, their effects in degrees were not exactly the same. These findings address the knowledge gap regarding mTORC1/2 dual inhibitors and lay a foundation for their further development and research.

Decoding mitochondria's role in immunity and cancer therapy

The functions of mitochondria, including energy production and biomolecule synthesis, have been known for a long time. Given the rising incidence of cancer, the role of mitochondria in cancer has become increasingly popular. Activated by components released by mitochondria, various pathways interact with each other to induce immune responses to protect organisms from attack. However, mitochondria play dual roles in the progression of cancer. Abnormalities in proteins, which are the elementary structures of mitochondria, are closely linked with oncogenesis. Both the aberrant accumulation of intermediates and mutations in enzymes result in the generation and progression of cancer. Therefore, targeting mitochondria to treat cancer may be a new strategy. Several drugs aimed at inhibiting mutated enzymes and accumulated intermediates have been tested clinically. Here, we discuss the current understanding of mitochondria in cancer and the interactions between mitochondrial functions, immune responses, and oncogenesis. Furthermore, we discuss mitochondria as hopeful targets for cancer therapy, providing insights into the progression of future therapeutic strategies.

Merging Metabolic Modeling and Imaging for Screening Therapeutic Targets in Colorectal Cancer

Cancer-associated fibroblasts (CAFs) play a key role in metabolic reprogramming and are well-established contributors to drug resistance in colorectal cancer (CRC). To exploit this metabolic crosstalk, we integrated a systems biology approach that identified key metabolic targets in a data-driven method and validated them experimentally. This process involved high-throughput computational screening to investigate the effects of enzyme perturbations predicted by a computational model of CRC metabolism to understand system-wide effects efficiently. Our results highlighted hexokinase (HK) as one of the crucial targets, which subsequently became our focus for experimental validation using patient-derived tumor organoids (PDTOs). Through metabolic imaging and viability assays, we found that PDTOs cultured in CAF conditioned media exhibited increased sensitivity to HK inhibition. Our approach emphasizes the critical role of integrating computational and experimental techniques in exploring and exploiting CRC-CAF crosstalk.

Reactive oxygen species in colorectal cancer adjuvant therapies

Colorectal cancer (CRC), a prevalent global malignancy, often necessitates adjuvant therapies such as chemotherapy, radiotherapy, targeted therapy, and immunotherapy to mitigate tumor burden in advanced stages. The efficacy of these therapies is significantly influenced by reactive oxygen species (ROS). Previous research underscores the pivotal role of ROS in gut pathology, targeted therapy, and drug resistance. ROS-mediated CRC adjuvant therapies encompass a myriad of mechanisms, including cell death and proliferation, survival and cell cycle, DNA damage, metabolic reprogramming, and angiogenesis. Preliminary clinical trials have begun to unveil the potential of ROS-manipulating therapy in enhancing CRC adjuvant therapies. This review aims to provide a comprehensive synthesis of studies exploring the role of ROS in CRC adjuvant therapies.

Rewiring of mitochondrial metabolism in therapy-resistant cancers: permanent and plastic adaptations

Deregulation of tumor cell metabolism is widely recognized as a "hallmark of cancer." Many of the selective pressures encountered by tumor cells, such as exposure to anticancer therapies, navigation of the metastatic cascade, and communication with the tumor microenvironment, can elicit further rewiring of tumor cell metabolism. Furthermore, phenotypic plasticity has been recently appreciated as an emerging "hallmark of cancer." Mitochondria are dynamic organelles and central hubs of metabolism whose roles in cancers have been a major focus of numerous studies. Importantly, therapeutic approaches targeting mitochondria are being developed. Interestingly, both plastic (i.e., reversible) and permanent (i.e., stable) metabolic adaptations have been observed following exposure to anticancer therapeutics. Understanding the plastic or permanent nature of these mechanisms is of crucial importance for devising the initiation, duration, and sequential nature of metabolism-targeting therapies. In this review, we compare permanent and plastic mitochondrial mechanisms driving therapy resistance. We also discuss experimental models of therapy-induced metabolic adaptation, therapeutic implications for targeting permanent and plastic metabolic states, and clinical implications of metabolic adaptations. While the plasticity of metabolic adaptations can make effective therapeutic treatment challenging, understanding the mechanisms behind these plastic phenotypes may lead to promising clinical interventions that will ultimately lead to better overall care for cancer patients.

A metabolic map of the DNA damage response identifies PRDX1 in the control of nuclear ROS scavenging and aspartate availability

While cellular metabolism impacts the DNA damage response, a systematic understanding of the metabolic requirements that are crucial for DNA damage repair has yet to be achieved. Here, we investigate the metabolic enzymes and processes that are essential for the resolution of DNA damage. By integrating functional genomics with chromatin proteomics and metabolomics, we provide a detailed description of the interplay between cellular metabolism and the DNA damage response. Further analysis identified that Peroxiredoxin 1, PRDX1, contributes to the DNA damage repair. During the DNA damage response, PRDX1 translocates to the nucleus where it reduces DNA damage-induced nuclear reactive oxygen species. Moreover, PRDX1 loss lowers aspartate availability, which is required for the DNA damage-induced upregulation of de novo nucleotide synthesis. In the absence of PRDX1, cells accumulate replication stress and DNA damage, leading to proliferation defects that are exacerbated in the presence of etoposide, thus revealing a role for PRDX1 as a DNA damage surveillance factor.

Design, Synthesis, and Evaluation of Glucose Transporter Inhibitor-SN38 Conjugates for Targeting Colorectal Cancer

Irinotecan (1), a prodrug of SN38 (2) approved by the US Food and Drug Administration for treating colorectal cancer, lacks specificity and causes many side effects. To increase the selectivity and therapeutic efficacy of this drug, we designed and synthesized conjugates of SN38 and glucose transporter inhibitors (phlorizin (5) or phloretin (6)), which could be hydrolyzed by glutathione or cathepsin to release SN38 in the tumor microenvironment, as a proof of concept. These conjugates (8, 9, and 10) displayed better antitumor efficacy with lower systemic exposure to SN38 in an orthotopic colorectal cancer mouse model compared with irinotecan at the same dosage. Further, no major adverse effects of the conjugates were observed during treatment. Biodistribution studies showed that conjugate 10 could induce higher concentrations of free SN38 in tumor tissues than irinotecan at the same dosage. Thus, the developed conjugates exhibit potential for treating colorectal cancer.

Antitumor Efficacy of Dual Blockade with Encorafenib + Cetuximab in Combination with Chemotherapy in Human BRAFV600E-Mutant Colorectal Cancer

PURPOSE

Encorafenib + cetuximab (E+C) is an effective therapeutic option in chemorefractory BRAFV600E metastatic colorectal cancer (mCRC). However, there is a need to improve the efficacy of this molecular-targeted therapy and evaluate regimens suitable for untreated BRAFV600E in patients with mCRC.

EXPERIMENTAL DESIGN

We performed a series of in vivo studies using BRAFV600E mCRC tumor xenografts. Mice were randomized to receive 5-fluoruracil (5-FU), irinotecan, or oxaliplatin regimens (FOLFIRI or FOLFOX), (E+C) or the combination. Patients received long-term treatment until disease progression, with deescalation strategies used to mimic maintenance therapy. Transcriptomic changes after progression on cytotoxic chemotherapy or targeted therapy were assessed.

RESULTS

Antitumor activity of either FOLFIRI or E+C was better as first-line treatment as compared with second-line, with partial cross-resistance seen between a cytotoxic regimen and targeted therapy with an average 62% loss of efficacy for FOLFIRI after E+C and a 45% loss of efficacy of E+C after FOLFIRI (P < 0.001 for both). FOLFIRI-treated models had upregulation of epithelial-mesenchymal transition (EMT) and MAPK pathway activation, where E+C treated models had suppressed MAPK signaling. In contrast, with chemotherapy with E+C, EMT and MAPK signaling remained suppressed. FOLFOX or FOLFIRI, each in combination with E+C, were the most active first-line treatments as compared with E+C or to chemotherapy alone. Furthermore, FOLFOX in combination with E+C as first-line induction therapy, followed by E+C ± 5-FU as maintenance therapy, was the most effective strategy for long-term disease control.

CONCLUSIONS

These results support the combination of cytotoxic chemotherapy and molecular-targeted therapy as a promising therapeutic approach in the first-line treatment of BRAFV600E mCRC.