A Phase IIb, single arm, multicenter trial of sacituzumab govitecan in Chinese patients with metastatic triple-negative breast cancer who received at least two prior treatments.

Refractory or relapsing metastatic triple-negative breast cancer (mTNBC) has a poor prognosis. Sacituzumab govitecan (SG) is a novel antibody-drug conjugate, targeting human trophoblast cell-surface antigen 2 (Trop-2). This is the first report of SG's efficacy and safety in Chinese patients with mTNBC. EVER-132-001 (NCT04454437) was a multicenter, single-arm, Phase IIb study in Chinese patients with mTNBC who failed ≥2 prior chemotherapy regimens. Eligible patients received 10 mg/kg SG on Days 1 and 8 of each 21-day treatment cycle, until disease progression/unacceptable toxicity. The primary endpoint was objective response rate (ORR) assessed by the Independent Review Committee. Secondary endpoints included: duration of response (DOR), clinical benefit rate (CBR), progression-free survival (PFS), overall survival (OS) and safety. Eighty female Chinese patients (median age 47.6 years; range 24-69.9 years) received ≥1 SG dose with a median of 8 treatment cycles by the cutoff date (August 6, 2021). Median number of prior systemic cancer treatments was 4.0 (range 2.0-8.0). ORR and CBR were reported 38.8% (95% confidence interval [CI]: 28.06-50.30) and 43.8% (95% CI, 32.68-55.30) of patients, respectively. The median PFS was 5.55 months (95% CI, 4.14-N/A). SG-related Grade ≥3 treatment-emergent adverse events (TEAEs) were reported in 71.3%, the most common were neutrophil count decreased (62.5%), white blood cell count decreased (48.8%) and anemia (21.3%); 6.3% discontinued SG because of TEAEs. SG demonstrated substantial clinical activity in heavily pretreated Chinese patients with mTNBC. The observed safety profile was generally manageable.

Deoxynivalenol globally affects the selection of 3' splice sites in human cells by suppressing the splicing factors, U2AF1 and SF1.

Deoxynivalenol (DON) is one of the most abundant mycotoxins and has adverse effects on several biological processes, posing risks of protein synthesis-disrupting effects and ribotoxic response. Therefore, chronic exposure to DON would fundamentally reshape the global expression pattern. Whether DON causes toxic effects on mRNA splicing, a fundamental biological process, remains unclear. In this study, we found that administration of the relative low dosage of DON dramatically changed the alternative splicing of pre-mRNA in HepG2 cells. The overall number of transcripts with aberrant selection of 3' splice sites was significantly increased in DON-exposed HepG2 cells. This effect was further confirmed in two other human cell lines, HEK293 and Caco-2, suggesting that this DON-induced alteration in splicing patterns was universal in human cells. Among these DON-induced changes in alternative splicing, the expression levels of two related splicing factors, SF1 and U2AF1, which are essential for 3' splice site recognitions, were strongly suppressed. Overexpression of either of the two splicing factors strongly alleviated the DON-induced aberrant selection of 3' splice sites. Moreover, SF1 was required for human cell proliferation in DON exposure, and the restoration of SF1 expression partially reinstated the proliferation potential for DON-treated cells. In conclusion, our study suggests that DON, even at a low dosage, has great potential to change gene expression globally by affecting not only protein synthesis but also mRNA processing in human cells.

T-2 toxin upregulates the expression of human cytochrome P450 1A1 (CYP1A1) by enhancing NRF1 and Sp1 interaction.

T-2 toxin is a major pollutant in crops and feedstuffs. Due to its high toxicity in a variety of organisms, T-2 toxin is of great concern as a threat to humans and to animal breeding. Overexpression of CYP1A1 may contribute to carcinogenesis, and CYP1A1 may be a promising target for the prevention and treatment of human malignancies. Therefore, it is essential to understand the regulatory mechanism by which T-2 toxin induces CYP1A1 expression in human cells. In this study, we confirmed that T-2 toxin (100 ng/mL) induced the expression of CYP1A1 in HepG2 cells through NRF1 and Sp1 bound to the promoter instead of through the well-recognized Aromatic hydrocarbon receptors (AhR). In cells treated with T-2 toxin, Sp1, but not NRF1, was significantly upregulated. However, T-2 toxin apparently promoted the interaction between NRF1 and Sp1 proteins, as revealed by IP analysis. Furthermore, in T-2 toxin-treated HepG2 cells, nuclear translocation of NRF1 was enhanced, while knockdown of Sp1 ablated NRF1 nuclear enrichment. Our results revealed that the upregulation of CYP1A1 by T-2 toxin in HepG2 cells depended on enhanced interaction between Sp1 and NRF1. This finding suggests the tumorigenic features of T-2 toxin might be related to the CYP1A1, which provides new insights to understand the toxicological effect of T-2 toxin.

AhR regulates the expression of human cytochrome P450 1A1 (CYP1A1) by recruiting Sp1.

Cytochrome P450 1A1 (CYP1A1) is abundant in the kidney, liver, and intestine and is involved in the phase I metabolism of numerous endogenous and exogenous compounds. Therefore, exploring the regulatory mechanism of its basal expression in humans is particularly important to understand the bioactivation of several procarcinogens to their carcinogenic derivatives. Site-specific mutagenesis and deletion of the transcription factor binding site determined the core cis-acting elements in the human CYP1A1 proximal and distal promoter regions. The proximal promoter region [overlapping xenobiotic-responsive element (XRE) and GC box sequences] determined the basal expression of CYP1A1. In human hepatocellular carcinoma cells (HepG2) with aryl hydrocarbon receptor (AhR) or specificity protein 1 (Sp1) knockdown, we confirmed that AhR and Sp1 are involved in basal CYP1A1 expression. In HepG2 cells overexpressing either AhR or Sp1, AhR determined the proximal transactivation of basal CYP1A1 expression. Via DNA affinity precipitation assays and ChIP, we found that AhR bound to the promoter and recruited Sp1 to transactivate CYP1A1 expression. The coordinated interaction between Sp1 and AhR was identified to be DNA mediated. Our work revealed a basal regulatory mechanism of an interesting human gene by which AhR interacts with Sp1 through DNA and recruits Sp1 to regulate basal CYP1A1 expression.

Efficacy and Tolerability of First-Line Cetuximab Plus Leucovorin, Fluorouracil, and Oxaliplatin (FOLFOX-4) Versus FOLFOX-4 in Patients With RAS Wild-Type Metastatic Colorectal Cancer: The Open-Label, Randomized, Phase III TAILOR Trial.

PURPOSE: Cetuximab in combination with chemotherapy is a standard-of-care first-line treatment regimen for patients with RAS wild-type (wt) metastatic colorectal cancer (mCRC); however, the efficacy of cetuximab plus leucovorin, fluorouracil, and oxaliplatin (FOLFOX) has never before been proven in a controlled and randomized phase III trial. To our knowledge, the TAILOR trial ( ClinicalTrials.gov identifier: NCT01228734) is the first randomized, multicenter, phase III study of the addition of cetuximab to first-line FOLFOX prospectively choosing a RAS wt population and thus providing confirmative data for the efficacy and safety of cetuximab plus FOLFOX versus FOLFOX alone. PATIENTS AND METHODS: TAILOR is an open-label, randomized (1:1), multicenter, phase III trial in patients from China comparing FOLFOX-4 with or without cetuximab in RAS wt (KRAS/NRAS, exons 2 to 4) mCRC. The primary end point of TAILOR was progression-free survival time; secondary end points included overall survival time, overall response rate, and safety and tolerability. RESULTS: In the modified intent-to-treat population of 393 patients with RAS wt mCRC, adding cetuximab to FOLFOX-4 significantly improved the primary end point of progression-free survival time compared with FOLFOX-4 alone (hazard ratio, 0.69; 95% CI, 0.54 to 0.89; P = .004; median, 9.2 v 7.4 months, respectively), as well as the secondary end points of overall survival time (current assessment after 300 events: hazard ratio, 0.76; 95% CI, 0.61 to 0.96; P = .02; median, 20.7 v 17.8 months, respectively) and overall response rate (odds ratio, 2.41; 95% CI, 1.61 to 3.61; P < .001; 61.1% v 39.5%, respectively). Treatment was well tolerated, and there were no new or unexpected safety findings. CONCLUSION: The TAILOR study met all of its objectives and relevant clinical end points, confirming cetuximab in combination with FOLFOX as an effective standard-of-care first-line treatment regimen for patients with RAS wt mCRC.