Early growth response factor 1 (EGR1) is a transcription factor that is mainly involved in the processes of tissue injury, immune responses, and fibrosis. Recent studies have shown that EGR1 is closely related to the initiation and progression of cancer and may participate in tumor cell proliferation, invasion, and metastasis and in tumor angiogenesis. Nonetheless, the specific mechanism whereby EGR1 modulates these processes remains to be elucidated. This review article summarizes possible mechanisms of action of EGR1 in tumorigenesis and tumor progression and may serve as a reference for clinical efficacy predictions and for the discovery of new therapeutic targets.

Objectives: We aim to determine the feasibility, safety, maximally tolerated dose (MTD), recommended dose and potential anti-tumor activity of intrathecal pemetrexed (IP). Materials and Methods: Lung adenocarcinoma patients with recurrent or progressive leptomeningeal metastases (LM) after intrathecal chemotherapy were recruited. IP dose was escalated from 10 mg. A minimum of three patients and a maximum of six were enrolled in each cohort. Schedule protocol was IP twice per week for 2 weeks in induction therapy, followed by once per week for 4 weeks in consolidation therapy. Serial samples of plasma and cerebrospinal fluid (CSF) were obtained for pharmacokinetic studies. Results: Thirteen patients were enrolled between March 2017 and July 2018. EGFR driver oncogene was identified in most of the patients. Severe adverse events (AEs) were encountered in 31% (4/13) of the cases, including myelosuppression, radiculitis, and elevation of hepatic aminotransferases (EHA). Study protocol was revised due to lethal myelosuppression. Following protocol revision, vitamin B12 and folic acid supplementation was given at the beginning of treatment, and myelosuppression was well-controlled. Dose-limiting toxicities (DLT) were myelosuppression, radiculitis, and EHA. Two patients (2/2) developed dose-limiting myelosuppression at 15 mg level. One patient (1/6) experienced dose-limiting radiculitis and EHA at 10 mg level. MTD was 10 mg. Response rate was 31% (4/13) and disease control rate was 54% (7/13). The drug concentration showed a decreasing trend in serial CSF samples following each IP. After IP, the peak plasma concentration was reached at 4 h in two cases, 6 h in two cases, 9 h in one case, and 12 h in one case, respectively. Conclusion: Pemetrexed was appropriate for intrathecal administration. IP at 10 mg dose in combination with vitamin supplementation on the schedule of 1–2 times per week showed controllable toxicity and good efficacy. This regimen paves the way for subsequent clinical trial. Clinical Trial Registration: www.ClinicalTrials.gov, identifier NCT03101579.

Purpose: A phase I/II study of intrathecal pemetrexed (IP) combined with involved-field radiotherapy (IFRT) was performed to determine feasibility, safety, and antitumor activity for leptomeningeal metastases (LM) from solid tumors. Methods: Participants first received induction IP administration, followed by concomitant radiotherapy within 3 days. The concomitant regimen consisted of IP (pemetrexed 10 mg, dexamethasone 5 mg, once per week, 4 times in 4 weeks) and IFRT (40 Gy in 20 fractions). Six participants were recruited to assess feasibility in phase I, and then 28 patients were recruited further. All patients were assessed to investigate safety, efficacy, and outcomes. Results: Between April 2018 and December 2018, 34 patients (male: 15; female: 19; median age: 56 years) were enrolled, including non-small-cell lung cancer (21), small-cell lung cancer (5), breast cancer (4), and others (4). Thirty-two patients received concurrent therapy and 25 (74%) patients completed the treatment. Major adverse events (AEs) consisted of myelosuppression, the elevation of hepatic aminotransferases, and radiculitis. Total AEs rate was 53% (18/34), including 6 (18%) patients with grade 3 and 1 (3%) with grade 4 AEs. The response rate was 68% (23/34). The median overall survival was 5.5 (0.3–16.6) months. Median neurological progression-free survival (NPFS) was 3.5 (0.3–15.2) months. Six-month NPFS rate was 47%. One-year survival rate was 21.6%. Conclusion: IP at a 10 mg dose on a schedule of 1–2 times per week presented good efficacy and safety in CSF. The concomitant regimen is an efficacious therapeutic option for LM patients with solid tumors. Trial Registration: This study (IPLM) was registered at https://register.clinicaltrials.gov [ClinicalTrials.gov identifier: NCT03507244].

Temozolomide (TMZ) is the mainstream chemotherapeutic drug for treating glioblastoma multiforme (GBM), but the intrinsic or acquired chemoresistance to TMZ has become the leading clinical concern, which is related to the repair of DNA alkylation sites by O⁶-methylguanine-DNA methyltransferase (MGMT). Pyrvinium pamoate (PP), the FDA-approved anthelminthic drug, has been reported to inhibit the Wnt/β-catenin pathway within numerous cancer types, and Wnt/β-catenin signaling pathway can modulate the expression of MGMT gene. However, whether PP affects the expression of MGMT and enhances TMZ sensitivity in GBM cells remains unclear. In the present study, we found that PP and TMZ had synergistic effect on inhibiting the viability of GBM cells, and PP induced inhibition of MGMT and enhanced the TMZ chemosensitivity of GBM cells through down-regulating Wnt/β-catenin pathway. Moreover, the overexpression of MGMT or β-catenin weakened the synergy between PP and TMZ. The mechanism of PP in inhibiting the Wnt pathway was indicated that PP resulted in the degradation of β-catenin via the AKT/GSK3β/β-catenin signaling axis. Moreover, Ser552 phosphorylation in β-catenin, which promotes its nuclear accumulation and transcriptional activity, is blocked by PP that also inhibits the Wnt pathway to some extent. The intracranial GBM mouse model also demonstrated that the synergy between PP and TMZ could be achieved through down-regulating β-catenin and MGMT, which prolonged the survival time of tumor-bearing mice. Taken together, our data suggest that PP may serve as the prospect medicine to improve the chemotherapeutic effect on GBM, especially for chemoresistant to TMZ induced by MGMT overexpression.

Glioblastoma (GBM) is a common malignant tumor in brain, and the treatment is still a challenge owing to the high invasiveness and the existence of blood-brain barrier (BBB). Although temozolomide (TMZ) is the first line medication, its efficacy is not ideal, which is related to the defect of dose distribution and drug resistance. It is urgent to develop a novel BBB-permeable nanoagent with multiple therapeutic modalities for improving the treatment effect of GBM. In this work, we constructed an intelligent BBB-permeable nanoplatform (CTHG-Lf NPs) with hollow mesoporous copper sulfide nanoparticles (HM-CuS NPs) as temozolomide (TMZ) carrier and hyaluronic acid (HA) as gatekeeper, as well as further modification with glucose oxidase (GOx) and lactoferrin (Lf) for highly efficient synergistic therapy of orthotopic GBM. The modification of Lf endows CTHG-Lf NPs with good target and BBB-permeable ability. HA not only prevents the TMZ leakage during circulation, but also achieves responsive drug release at tumor site for effective chemotherapy (CT). GOx provides high hydrogen peroxide (H₂O₂) and gluconic acid for improving the treatment effect of chemodynamic therapy (CDT), and realizes the starvation therapy (ST) by consuming glucose. The good photothermal effect of CTHG-Lf NPs achieves the "mild" photothermal therapy (PTT), while enhancing the efficiency of Fenton-like reaction. The synergistic strategy with CT/CDT/PTT/ST can not only promote brain drug delivery, but also realize the combination of multiple mechanisms for effective tumor growth suppression in vivo.