Background Surgery is the main modality of cure for solid cancers and was prioritised to continue during COVID-19 outbreaks. This study aimed to identify immediate areas for system strengthening by comparing the delivery of elective cancer surgery during the COVID-19 pandemic in periods of lockdown versus light restriction. Methods This international, prospective, cohort study enrolled 20 006 adult (≥18 years) patients from 466 hospitals in 61 countries with 15 cancer types, who had a decision for curative surgery during the COVID-19 pandemic and were followed up until the point of surgery or cessation of follow-up (Aug 31, 2020). Average national Oxford COVID-19 Stringency Index scores were calculated to define the government response to COVID-19 for each patient for the period they awaited surgery, and classified into light restrictions (index <20), moderate lockdowns (20–60), and full lockdowns (>60). The primary outcome was the non-operation rate (defined as the proportion of patients who did not undergo planned surgery). Cox proportional-hazards regression models were used to explore the associations between lockdowns and non-operation. Intervals from diagnosis to surgery were compared across COVID-19 government response index groups. This study was registered at ClinicalTrials.gov , NCT04384926 . Findings Of eligible patients awaiting surgery, 2003 (10·0%) of 20 006 did not receive surgery after a median follow-up of 23 weeks (IQR 16–30), all of whom had a COVID-19-related reason given for non-operation. Light restrictions were associated with a 0·6% non-operation rate (26 of 4521), moderate lockdowns with a 5·5% rate (201 of 3646; adjusted hazard ratio [HR] 0·81, 95% CI 0·77–0·84; p<0·0001), and full lockdowns with a 15·0% rate (1775 of 11 827; HR 0·51, 0·50–0·53; p<0·0001). In sensitivity analyses, including adjustment for SARS-CoV-2 case notification rates, moderate lockdowns (HR 0·84, 95% CI 0·80–0·88; p<0·001), and full lockdowns (0·57, 0·54–0·60; p<0·001), remained independently associated with non-operation. Surgery beyond 12 weeks from diagnosis in patients without neoadjuvant therapy increased during lockdowns (374 [9·1%] of 4521 in light restrictions, 317 [10·4%] of 3646 in moderate lockdowns, 2001 [23·8%] of 11 827 in full lockdowns), although there were no differences in resectability rates observed with longer delays. Interpretation Cancer surgery systems worldwide were fragile to lockdowns, with one in seven patients who were in regions with full lockdowns not undergoing planned surgery and experiencing longer preoperative delays. Although short-term oncological outcomes were not compromised in those selected for surgery, delays and non-operations might lead to long-term reductions in survival. During current and future periods of societal restriction, the resilience of elective surgery systems requires strengthening, which might include...

1a,25-dihydroxyvitamin D 3 (1,25D 3 ) is a powerful differentiation agent, which has potential for treatment of myeloid leukemias and other types of cancer, but the calcemia produced by pharmacologically active doses precludes the use of this agent in the clinic. We have shown that carnosic acid, the major rosemary polyphenol, enhances the differentiating and antiproliferative effects of low concentrations of 1,25D 3 in human myeloid leukemia cell lines (HL60, U937). Here we translated these findings to in vivo conditions using a syngeneic mouse leukemia tumor model. To this end, we first demonstrated that as in HL60 cells, differentiation of WEHI-3B D 2 murine myelomonocytic leukemia cells induced by 1 nM 1,25D 3 or its low-calcemic analog, 1,25-dihydroxy-16-ene-5,6-trans-cholecalciferol (Ro25-4020), can be synergistically potentiated by carnosic acid (10 lM) or the carnosic acid-rich ethanolic extract of rosemary leaves. This effect was accompanied by cell cycle arrest in G01G1 phase and a marked inhibition of cell growth. In the in vivo studies, i.p. injections of 2 lg Ro25-4020 in Balb/c mice bearing WEHI-3B D 2 tumors produced a significant delay in tumor appearance and reduction in tumor size, without significant toxicity. Another analog, 1,25-dihydroxy-16,23Z-diene-20-epi-26,27-hexafluoro-19-nor-cholecalciferol (Ro26-3884) administered at the same dose was less effective than Ro25-4020 and profoundly toxic. Importantly, combined treatment with 1% dry rosemary extract (mixed with food) and 1 lg Ro25-4020 resulted in a strong cooperative antitumor effect, without inducing hypercalcemia. These results indicate for the first time that a plant polyphenolic preparation and a vitamin D derivative can cooperate not only in inducing leukemia cell differentiation in vitro, but also in the antileukemic activity in vivo. These data may suggest novel protocols for chemoprevention or differentiation therapy of myeloid leukemia. ' 2006 Wiley-Liss, Inc.

No abstract

Objective: Differentiation therapy with the hormonal form of vitamin D, 1α,25-dihydroxyvitamin D₃ (1,25D₃), is a promising approach to treatment of acute myeloid leukemia (AML); however, 1,25D₃ induces hypercalcemia at pharmacologically active doses. We investigated the in vitro and in vivoantileukemic efficacy of combined treatment with non-toxic doses of a low-calcemic 1,25D₃ analogue, 1,25-dihydroxy-21(3-hydroxy-3-methyl-butyl)-19-nor-cholecalciferol (19-nor-Gemini; Ro27-5646), and rosemary plant agents in a mouse model of AML. Methods: Proliferation and differentiation of WEHI-3B D– (WEHI) murine myelomonocytic leukemia cellsin vitro were determined by standard assays. Reactive oxygen species, glutathione and protein expression levels were measured by flow cytometry, enzymatic assay and Western blotting, respectively. Systemic AML was developed by intravenous injection of WEHI cells in syngeneic Balb/c mice. Results: 19-nor-Gemini had a higher potency than its parent compounds, Gemini (Ro27-2310) and 1,25D₃, in the induction of differentiation (EC₅₀ = 0.059 ± 0.011, 0.275 ± 0.093 and 0.652 ± 0.085 nM, respectively) and growth arrest (IC₅₀ = 0.072 ± 0.018, 0.165 ± 0.061 and 0.895 ± 0.144 nM, respectively) in WEHI cells in vitro, and lower in vivo toxicity. Combined treatment of leukemia-bearing mice with 19-nor-Gemini (injected intraperitoneally) and standardized rosemary extract (mixed with food) resulted in a synergistic increase in survival (from 42.2 ± 2.5 days in untreated mice to 66.5 ± 4.2 days, n = 3) and normalization of white blood cell and differential counts. This was consistent with strong cooperative antiproliferative and differentiation effects of low concentrations of 19-nor-Gemini or 1,25D₃ combined with rosemary extract or its major polyphenolic component, carnosic acid, as well as with the antioxidant action of rosemary agents and vitamin D derivatives in WEHI cell cultures. Conclusion: Combined effectiveness of 1,25D₃ analogues and rosemary agents against mouse AML warrants further exploration of this therapeutic approach in translational models of human leukemia.

Vitamin D derivatives, including its physiological form 1α,25(OH)2 vitamin D3 (1,25D), have anti-tumor actions demonstrated in cell culture and confirmatory epidemiological associations are frequently reported. However, their promise for use in the cancer clinic is still incompletely fulfilled, suggesting that a better understanding of the molecular events initiated by these compounds is needed for therapeutic advances. While ERK1/2 has been intensely investigated and is known to transmit signals for cell survival, growth, and differentiation, the role of other MAPK pathways has been studied sporadically. Therefore, we utilized acute myeloid leukemia (AML) cells in culture (HL60 and U937), to determine if ERK5 has a role in 1,25D-induced terminal differentiation which is distinct from the previously shown involvement of ERK1/2. We previously found that inhibition of kinase activity of ERK5 by specific pharmacological inhibitors BIX02189 or XMD8-92 results in higher expression of general myeloid marker CD11b, but a lower expression of the monocytic marker CD14. In contrast, the inhibition of the ERK1/2 pathway by PD98059 or U0126 reduced the expression of all differentiation markers studied. We report here for the first time that the differentiation changes induced by ERK5 inhibitors are accompanied by the inhibition of cell proliferation, and this occurs in the both G1 and G2 phases of the cell cycle. Of note, inhibition of ERK5 auto-phosphorylation by XMD8-92 results in a particularly robust cell cycle arrest in G2 phase in AML cells. This study provides a link between the 1,25D-elevated ERK5 pathway and changes in the cell cycle phase transitions in AML cells. Thus, combinations of vitamin D derivatives and ERK5 inhibitors may be more successful in cancer clinics than 1,25D or analogs alone.