bims-instec Biomed News
on Intestinal stem cells and chemoresistance in colon cancer and intestinal regeneration
Issue of 2022‒07‒31
five papers selected by
Maria-Virginia Giolito

  1. Cells. 2022 Jul 20. pii: 2243. [Epub ahead of print]11(14):
      Renewal of the intestinal epithelium is orchestrated by regenerative epithelial proliferation within crypts. Recent studies have shown that lysophosphatidic acid (LPA) can maintain intestinal epithelial renewal in vitro and conditional deletion of Lpar5 (Lpar5iKO) in mice ablates the intestinal epithelium and increases morbidity. In contrast, constitutive Lpar5 deletion (Lpar5cKO) does not cause a defect in intestinal crypt regeneration. In this study, we investigated whether another LPA receptor (LPAR) compensates for constitutive loss of LPA5 function to allow regeneration of intestinal epithelium. In Lpar5cKO intestinal epithelial cells (IECs), Lpar2 was upregulated and blocking LPA2 function reduced proliferation and increased apoptosis of Lpar5cKO IECs. Similar to Lpar5cKO mice, the absence of Lpar2 (Lpar2-/-) resulted in upregulation of Lpar5 in IECs, indicating that LPA2 and LPA5 reciprocally compensate for the loss of each other. Blocking LPA2 in Lpar5cKO enteroids reduced phosphorylation of Akt, indicating that LPA2 maintains the growth of Lpar5cKO enteroids through activation of the PI3K-Akt pathway. The present study provides evidence that loss of an LPAR can be compensated by another LPAR. This ability to compensate needs to be considered in studies aimed to define receptor functions or test the efficacy of a LPAR-targeting drug using genetically engineered animal models.
    Keywords:  LPA5; epithelial cells; intestine; lysophosphatidic acid; organoid
  2. Front Oncol. 2022 ;12 949715
      Objective: Disruption of the circadian rhythm is associated with cancer occurrence, response to chemotherapy, and poor prognosis. Thus, using internal clock-based chronotherapy to optimize the administration time may improve the therapeutic effects of anticancer drugs while reducing the side effects. Chronotherapy with 5-fluorouracil (5-FU) has been observed in colorectal cancer (CRC) for a long time, but its effect is under controversial and the mechanism remains unclear.Methods: Genome-wide clustered regularly interspaced short palindromic repeats (CRISPR) screening and RNA-sequencing were combined to identify the potential genes or pathways involved in 5-FU chronochemotherapy. Genetic deletion or overexpression of pyrimidine metabolic pathway genes were conducted to examine cellular viability with or without 5-FU via flow cytometry. Western blotting, qPCR, chromatin immunoprecipitation, gain-of-function and loss-of-function assays of several CRC cell lines in vitro and in vivo were used to elaborate and validate the mechanism of 5-FU chronotherapeutic effects.
    Results: Chronochemotherapeutic effects of 5-FU on CRC in vivo were verified. Furthermore, 5-FU chronochemotherapy related genes such as UPP2, UCK2 and UMPS in the pyrimidine metabolic pathway were identified. Disturbance in these genes, especially UMPS, perturbs 5-FU treatment outcomes in CRC cells. Mechanistically, the core circadian gene, brain and muscle aryl hydrocarbon receptor nuclear translocator-like protein-1 (BMAL1), extensively regulate gene expression in pyrimidine metabolic pathway by binding to E-box element in the promoter region of key genes such as UMPS and perturb their enzymatic activities, thereby maintain diurnal efficacy of 5-FU in CRC cells.
    Conclusion: This study uncovered a new mechanism by which a core circadian gene BMAL1 increases the effectiveness of 5-FU by enhancing the expression and enzymatic activities of key genes in the pyrimidine metabolic pathway in CRC cells. The findings suggest a novel strategy for CRC chemotherapy by targeting chrono-modulated genes of the 5-FU metabolic pathway.
    Keywords:  5-fluorouracil; BMAL1; CRISPR screening; chronochemotherapy; circadian rhythm
  3. Acta Biochim Biophys Sin (Shanghai). 2022 May 25. 54(7): 1-12
      More and more patients with advanced colorectal cancer (CRC) have benefited from surgical resection or ablation following neoadjuvant chemoradiotherapy (nCRT), but nCRT may be ineffective and have potential risks to some patients. Therefore, it is necessary to discover effective biomarkers for predicting the nCRT efficacy in CRC patients. Chromokinesin Kif4A plays a critical role in mitosis, DNA damage repair and tumorigenesis, but its relationship with nCRT efficacy in advanced CRC remains unclear. Here, we find that Kif4A expression in pretreated tumor tissue is positively correlated with poorer tumor regression after receiving nCRT ( P=0.005). Knockdown of endogenous Kif4A causes an increased sensitivity of CRC cells to chemotherapeutic drugs 5-fluorouracil (5-FU) and Cisplatin (DDP), while overexpression of Kif4A enhances resistance of CRC cells to the chemotherapeutic drugs. Furthermore, depending on its motor domain and tail domain, Kif4A regulates DNA damage response (DDR) induced by 5-FU or DDP treatment in CRC cells. In conclusion, we demonstrate that Kif4A may be a potential independent biomarker for predicting the nCRT efficacy in advanced CRC patients, and Kif4A regulates chemosensitivity of CRC cells through controlling DDR.
    Keywords:  DNA damage response; Kif4A; apoptosis; colorectal cancer; neoadjuvant chemoradiotherapy
  4. Biomedicines. 2022 Jun 22. pii: 1474. [Epub ahead of print]10(7):
      The use of zebrafish embryos for personalized medicine has become increasingly popular. We present a co-clinical trial aiming to evaluate the use of zPDX (zebrafish Patient-Derived Xenografts) in predicting the response to chemotherapy regimens used for colorectal cancer patients. zPDXs are generated by xenografting tumor tissues in two days post-fertilization zebrafish embryos. zPDXs were exposed to chemotherapy regimens (5-FU, FOLFIRI, FOLFOX, FOLFOXIRI) for 48 h. We used a linear mixed effect model to evaluate the zPDX-specific response to treatments showing for 4/36 zPDXs (11%), a statistically significant reduction of tumor size compared to controls. We used the RECIST criteria to compare the outcome of each patient after chemotherapy with the objective response of its own zPDX model. Of the 36 patients enrolled, 8 metastatic colorectal cancer (mCRC), response rate after first-line therapy, and the zPDX chemosensitivity profile were available. Of eight mCRC patients, five achieved a partial response and three had a stable disease. In 6/8 (75%) we registered a concordance between the response of the patient and the outcomes reported in the corresponding zPDX. Our results provide evidence that the zPDX model can reflect the outcome in mCRC patients, opening a new frontier to personalized medicine.
    Keywords:  chemosensitivity; colorectal cancer; personalized medicine; preclinical model; zebrafish avatar
  5. Cancer Discov. 2022 Jul 29. pii: CD-21-1026. [Epub ahead of print]
      Chimeric Antigen Receptor T-cell (CART) immunotherapy led to unprecedented responses in patients with refractory/relapsed B-cell non-Hodgkin lymphoma (NHL); nevertheless, two-thirds of patients fail this treatment. Resistance to apoptosis is a key feature of cancer cells that associates with treatment failure. In 87 NHL patients treated with anti-CD19 CART, we found that chromosomal alteration of BCL-2, a critical anti-apoptotic regulator, in lymphoma cells was associated with reduced survival. Therefore, we combined CART19 with the FDA-approved BCL-2-inhibitor, venetoclax, and demonstrated in vivo synergy in venetoclax-sensitive NHL. However, higher venetoclax doses for venetoclax-resistant lymphomas resulted in CART toxicity. To overcome this limitation, we developed venetoclax-resistant CART by overexpressing mutated BCL-2(F104L) which is not recognized by venetoclax. Notably, BCL-2(F104L)-CART19 synergized with venetoclax in multiple lymphoma xenograft models. Furthermore, we uncovered that BCL-2 overexpression in T cells per se enhanced CART anti-tumor activity in preclinical models and in patients by prolonging CART persistence.