The aldehyde dehydrogenase enzyme 7A1 is functionally involved in prostate cancer bone metastasis

High aldehyde dehydrogenase (ALDH) activity can be used to identify tumor-initiating and metastasis-initiating cells in various human carcinomas, including prostate cancer. To date, the functional importance of ALDH enzymes in prostate carcinogenesis, progression and metastasis has remained elusive. Previously we identified strong expression of ALDH7A1 in human prostate cancer cell lines, primary tumors and matched bone metastases. In this study, we evaluated whether ALDH7A1 is required for the acquisition of a metastatic stem/progenitor cell phenotype in human prostate cancer. Knockdown of ALDH7A1 expression resulted in a decrease of the α2hi/αvhi/CD44+ stem/progenitor cell subpopulation in the human prostate cancer cell line PC-3M-Pro4. In addition, ALDH7A1 knockdown significantly inhibited the clonogenic and migratory ability of human prostate cancer cells in vitro. Furthermore, a number of genes/factors involved in migration, invasion and metastasis were affected including transcription factors (snail, snail2, and twist) and osteopontin, an ECM molecule involved in metastasis. Knockdown of ALDH7A1 resulted in decreased intra-bone growth and inhibited experimentally induced (bone) metastasis, while intra-prostatic growth was not affected. In line with these observations, evidence is presented that TGF-β, a key player in cancer invasiveness and bone metastasis, strongly induced ALDH activity while BMP7 (an antagonist of TGF-β signaling) down-regulated ALDH activity. Our findings show, for the first time, that the ALDH7A1 enzyme is functionally involved in the formation of bone metastases and that the effect appeared dependent on the microenvironment, i.e., bone versus prostate

Expanding the role of village malaria workers in Cambodia: Implementation and evaluation of four health education packages

Background: Early access to correct diagnosis and appropriate treatment is essential for malaria elimination, and in Cambodia this relies on village malaria workers (VMWs). Decreasing malaria transmission leave VMWs with diminished roles. Activities related to the control of other health conditions could keep these community health workers relevant. Methods: During 2022, 120 VMWs attended training at local health centres on four health education packages: 1. hygiene and sanitation; 2. disease surveillance; 3. management of mild illness; 4. vaccination and antenatal care. All training and evaluation sessions were documented through meeting minutes, and 19 focus group discussions (FGDs) were conducted among VMWs and health centre personnel. Audio-records of FGDs were transcribed and translated in English and underwent thematic analysis. Results: VMWs reported strong interest in the training and welcomed the expansion of their roles thus assuring their continued relevance. VMWs prioritized disease surveillance and management of mild illness among the available training packages because these topics were seen as most relevant. While training was considered comprehensible and important, the low literacy among VMWs was an impediment suggesting training materials need to be delivered visually. Since VMWs have limited resources, incentives could ensure that VMWs are motivated to undertake additional roles and responsibilities. Conclusions: The transformation of VMWs into community health workers with roles beyond malaria is a promising approach for sustaining health care provision in remote areas. Training needs to consider the low scientific literacy, time constraints and limited resources of VMWs

Triple therapy with artemether-lumefantrine plus amodiaquine versus artemether-lumefantrine alone for artemisinin-resistant, uncomplicated falciparum malaria: an open-label, randomised, multicentre trial

Background: Late treatment failures after artemisinin-based combination therapies (ACTs) for falciparum malaria have increased in the Greater Mekong subregion in southeast Asia. Addition of amodiaquine to artemether-lumefantrine could provide an efficacious treatment for multidrug-resistant infections. Methods: We conducted an open-label, randomised trial at five hospitals or health centres in three locations (western Cambodia, eastern Cambodia, and Vietnam). Eligible participants were male and female patients aged 2-65 years with uncomplicated Plasmodium falciparum malaria. Patients were randomly allocated (1:1 in blocks of eight to 12) to either artemether-lumefantrine alone (dosed according to WHO guidelines) or artemether-lumefantrine plus amodiaquine (10 mg base per kg/day), both given orally as six doses over 3 days. All received a single dose of primaquine (0·25 mg/kg) 24 h after the start of study treatment to limit transmission of the parasite. Parasites were genotyped, identifying artemisinin resistance. The primary outcome was Kaplan-Meier 42-day PCR-corrected efficacy against recrudescence of the original parasite, assessed by intent-to-treat. Safety was a secondary outcome. This completed trial is registered at ClinicalTrials.gov (NCT03355664). Findings: Between March 18, 2018, and Jan 30, 2020, 310 patients received randomly allocated treatment; 154 received artemether-lumefantrine alone and 156 received artemether-lumefantrine plus amodiaquine. Parasites from 305 of these patients were genotyped. 42-day PCR-corrected treatment efficacy was noted in 151 (97%, 95% CI 92-99) of 156 patients with artemether-lumefantrine plus amodiaquine versus 146 (95%, 89-97) of 154 patients with artemether-lumefantrine alone; hazard ratio (HR) for recrudescence 0·6 (95% CI 0·2-1·9, p=0·38). Of the 13 recrudescences, 12 were in 174 (57%) of 305 infections with pfkelch13 mutations indicating artemisinin resistance, for which 42-day efficacy was noted in 89 (96%) of 93 infections with artemether-lumefantrine plus amodiaquine versus 73 (90%) of 81 infections with artemether-lumefantrine alone; HR for recrudescence 0·44 (95% CI 0·14-1·40, p=0·17). Artemether-lumefantrine plus amodiaquine was generally well tolerated, but the number of mild (grade 1-2) adverse events, mainly gastrointestinal, was greater in this group compared with artemether-lumefantrine alone (vomiting, 12 [8%] with artemether-lumefantrine plus amodiaquine vs three [2%] with artemether-lumefantrine alone, p=0·03; and nausea, 11 [7%] with artemether-lumefantrine plus amodiaquine vs three [2%] with artemether-lumefantrine alone, p=0·05). Early vomiting within 1 h of treatment, requiring retreatment, occurred in no patients of 154 with artemether-lumefantrine alone versus five (3%) of 156 with artemether-lumefantrine plus amodiaquine, p=0·06. Bradycardia (≤54 beats/min) of any grade was noted in 59 (38%) of 154 patients with artemether-lumefantrine alone and 95 (61%) of 156 with artemether-lumefantrine plus amodiaquine, p=0·0001. Interpretation: Artemether-lumefantrine plus amodiaquine provides an alternative to artemether-lumefantrine alone as first-line treatment for multidrug-resistant P falciparum malaria in the Greater Mekong subregion, and could prolong the therapeutic lifetime of artemether-lumefantrine in malaria-endemic populations

Pf7: an open dataset of Plasmodium falciparum genome variation in 20,000 worldwide samples

We describe the MalariaGEN Pf7 data resource, the seventh release of Plasmodium falciparum genome variation data from the MalariaGEN network.  It comprises over 20,000 samples from 82 partner studies in 33 countries, including several malaria endemic regions that were previously underrepresented.  For the first time we include dried blood spot samples that were sequenced after selective whole genome amplification, necessitating new methods to genotype copy number variations.  We identify a large number of newly emerging crt mutations in parts of Southeast Asia, and show examples of heterogeneities in patterns of drug resistance within Africa and within the Indian subcontinent.  We describe the profile of variations in the C-terminal of the csp gene and relate this to the sequence used in the RTS,S and R21 malaria vaccines.  Pf7 provides high-quality data on genotype calls for 6 million SNPs and short indels, analysis of large deletions that cause failure of rapid diagnostic tests, and systematic characterisation of six major drug resistance loci, all of which can be freely downloaded from the MalariaGEN website

Comment on Weitzman et al. Resistance to Antimalarial Monotherapy Is Cyclic. <i>J. Clin. Med.</i> 2022, <i>11</i>, 781

Weitzman et al. used PubMed text mining to determine the trends of antimalarial resistance over the last 40 years [...

Triple Artemisinin-Based Combination Therapies for Malaria – A New Paradigm?

Recent gains in the fight against malaria are threatened by the emergence and spread of artemisinin and partner drug resistance in Plasmodium falciparum in the Greater Mekong Subregion (GMS). When artemisinins are combined with a single partner drug, all recommended artemisinin-based combination therapies have shown reduced efficacy in some countries in the GMS at some point. Novel drugs are not available for the near future. Triple artemisinin-based combination therapies, combining artemisinins with two currently available partner drugs, will provide one of the last remaining safe and effective treatments for falciparum malaria that can be deployed rapidly in the GMS, whereas their deployment beyond the GMS could delay or prevent the global emergence and spread of resistance to currently available drugs

Are national treatment guidelines for falciparum malaria in line with WHO recommendations and is antimalarial resistance taken into consideration? – A review of guidelines in non-endemic countries

Objective: Plasmodium falciparum infections are a relatively rare but potentially deadly disease found in returning travellers. We compare the national treatment guidelines of non-endemic countries with the WHO guidelines for the treatment of Plasmodium falciparum infections. Methods: Review. We identified non-endemic countries with an incidence rate of imported malaria of at least one per 100,000 population and at least 50 cases annually. Using PubMed and Google Search, we reviewed national guidelines published before 1 March 2021. Results: Thirteen guidelines were identified. For uncomplicated falciparum malaria, 11 of 13 countries (85%) recommend an artemisinin-based combination therapy as first-line regimen in adults, of which artemether–lumefantrine was the most common. For severe malaria, all guidelines recommend the use of intravenous artesunate. Only three countries adjust treatment recommendations based on expected artemisinin resistance. Conclusion: Treatment guidelines for uncomplicated falciparum malaria in non-endemic countries generally adhere to WHO recommendations but often fail to mention the risk of drug resistance in returning travellers. Artemisinin-based Combination Therapies (ACTs) should be the first choice for all uncomplicated malaria cases. Furthermore, the choice between ACTs should be based on regional resistance patterns

Short tandem repeat polymorphism in the promoter region of cyclophilin 19B drives its transcriptional upregulation and contributes to drug resistance in the malaria parasite Plasmodium falciparum

Resistance of the human malaria parasites, Plasmodium falciparum, to artemisinins is now fully established in Southeast Asia and is gradually emerging in Sub-Saharan Africa. Although nonsynonymous SNPs in the pfk13 Kelch-repeat propeller (KREP) domain are clearly associated with artemisinin resistance, their functional relevance requires cooperation with other genetic factors/alterations of the P. falciparum genome, collectively referred to as genetic background. Here we provide experimental evidence that P. falciparum cyclophilin 19B (PfCYP19B) may represent one putative factor in this genetic background, contributing to artemisinin resistance via its increased expression. We show that overexpression of PfCYP19B in vitro drives limited but significant resistance to not only artemisinin but also piperaquine, an important partner drug in artemisinin-based combination therapies. We showed that PfCYP19B acts as a negative regulator of the integrated stress response (ISR) pathway by modulating levels of phosphorylated eIF2α (eIF2α-P). Curiously, artemisinin and piperaquine affect eIF2α-P in an inverse direction that in both cases can be modulated by PfCYP19B towards resistance. Here we also provide evidence that the upregulation of PfCYP19B in the drug-resistant parasites appears to be maintained by a short tandem repeat (SRT) sequence polymorphism in the gene's promoter region. These results support a model that artemisinin (and other drugs) resistance mechanisms are complex genetic traits being contributed to by altered expression of multiple genes driven by genetic polymorphism at their promoter regions