Mistletoe Plant Extract in Patients with Nonmuscle Invasive Bladder Cancer: Results of a Phase Ib/IIa Single Group Dose Escalation Study

Mistletoe Extracts from Different Host Trees Disparately Inhibit Bladder Cancer Cell Growth and Proliferation

Extracts of European mistletoe (Viscum album) are popular as a complementary treatment for patients with many different cancer types. However, whether these extracts actually block bladder cancer progression remains unknown. The influence of different mistletoe extracts on bladder cancer cell growth and proliferation was investigated by exposing RT112, UMUC3, and TCCSup cells to mistletoe from hawthorn (Crataegi), lime trees (Tiliae), willow trees (Salicis), or poplar trees (Populi). The tumor cell growth and proliferation, apoptosis induction, and cell cycle progression were then evaluated. Alterations in integrin α and β subtype expression as well as CD44 standard (CD44s) and CD44 variant (CD44v) expressions were evaluated. Cell cycle-regulating proteins (CDK1 and 2, Cyclin A and B) were also investigated. Blocking and knock-down studies served to correlate protein alterations with cell growth. All extracts significantly down-regulated the growth and proliferation of all bladder cancer cell lines, most strongly in RT112 and UMUC3 cells. Alterations in CD44 expression were not homogeneous but rather depended on the extract and the cell line. Integrin α3 was, likewise, differently modified. Integrin α5 was diminished in RT112 and UMUC3 cells (significantly) and TCCSup (trend) by Populi and Salicis. Populi and Salicis arrested UMUC3 in G0/G1 to a similar extent, whereas apoptosis was induced most efficiently by Salicis. Examination of cell cycle-regulating proteins revealed down-regulation of CDK1 and 2 and Cyclin A by Salicis but down-regulation of CDK2 and Cyclin A by Populi. Blocking and knock-down studies pointed to the influence of integrin α5, CD44, and the Cyclin-CDK axis in regulating bladder cancer growth. Mistletoe extracts do block bladder cancer growth in vitro, with the molecular action differing according to the cell line and the host tree of the mistletoe. Integrating mistletoe into a guideline-based treatment regimen might optimize bladder cancer therapy.

Systematic analysis of mistletoe prescriptions in clinical studies

Purpose

Mistletoe treatment is discussed controversial as a complementary treatment for cancer patients. Aim of this systematic analysis is to assess the concept of mistletoe treatment in the clinical studies with respect to indication, type of mistletoe preparation, treatment schedule, aim of treatment, and assessment of treatment results.

Methods

In the period from August to December 2020, the following databases were systematically searched: Medline, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), PsycINFO, CINAHL, and “Science Citation Index Expanded” (Web of Science). We assessed all studies for study types, methods, endpoints and mistletoe preparations including their ways of application, host trees and dosage schedules.

Results

The search concerning mistletoe therapy revealed 3296 hits. Of these, 102 publications and at total of 19.441 patients were included. We included several study types investigating the application of mistletoe in different groups of participants (cancer patients of any type of cancer were included as well as studies conducted with healthy volunteers and pediatric patients). The most common types of cancer were breast cancer, pancreatic cancer, colorectal cancer and malignant melanoma. Randomized controlled studies, cohort studies and case reports make up most of the included studies. A huge variety was observed concerning type and composition of mistletoe extracts (differing pharmaceutical companies and host trees), ways of applications and dosage schedules. Administration varied e. g. between using mistletoe extract as sole treatment and as concomitant therapy to cancer treatment. As the analysis of all studies shows, there is no relationship between mistletoe preparation used, host tree and dosage, and cancer type.

Conclusions

Our research was not able to deviate transparent rules or guidelines with respect to mistletoe treatment in cancer care.

Mistletoe extracts for cancer treatment

This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

To assess the effects of mistletoe extracts (Viscum album , European mistletoe) as antitumour treatment and for supportive/palliative care in adults with cancer. We will assess whether mistletoe extracts administered alone or in combination with tumour‐specific therapies prolong progression free‐intervals (PFI) and/or overall survival (OS); enhance tumour response; alleviate treatment‐related adverse effects from conventional cancer treatment e.g. chemo‐ or radiotherapy; improve patient‐reported outcomes including health‐related QOL; and whether mistletoe extracts produce adverse effects.

Aloperine Exerts Antitumor Effects on Bladder Cancer in vitro

Background

Human bladder cancer is the most common malignant tumor of the urinary system and one of the 10 most common tumors of the whole body. Although most patients with bladder cancer exhibit a good prognosis with standard treatment, effective therapies for patients with a recurrent or advanced bladder cancer are unavailable. Therefore, highly effective drugs to treat such patients need to be developed. Aloperine (ALO), a natural compound isolated from Sophora alopecuroides, has antitumor properties. However, the role of ALO in human bladder cancer remains unclear.

Methods

In the present study, MTT was used to detect the cytotoxic effect of ALO on human BC cell line EJ and human urothelium cell line SV-HUC-1cells. Meanwhile, in order to investigate the effects of ALO on the proliferation, apoptosis, migration, and invasion of BC EJ cells and its mechanism by Cell Counting Kit-8 (CCK-8) assay, immunofluorescence, Hoechst 33342 staining, wound scratch assay, transwell migration and invasion assay, Western blot analysis.

Results

ALO can inhibit the proliferation and invasion of human bladder cancer EJ cells, and is low-toxic to human urothelium cells. Moreover, it can promote cellular apoptosis in vitro. Further analysis demonstrated the involvement of Caspase-dependent apoptosis following ALO treatment. ALO also downregulated the protein expression levels of Ras, p-Raf1 and p-Erk1/2.

Conclusion

ALO is a potential drug for human bladder cancer therapy.

Efficacy of mistletoe extract as a complement to standard treatment in advanced pancreatic cancer: study protocol for a multicentre, parallel group, double-blind, randomised, placebo-controlled clinical trial (MISTRAL)

Background

Most pancreatic cancer patients present with advanced stage at diagnosis with extremely short expected survival and few treatment options. A multimodal palliative approach is necessary for symptom relief and optimisation of health-related quality of life. In a recent open-label trial of mistletoe extract for advanced pancreatic cancer patients not eligible for chemotherapy, promising results on improved overall survival and better health-related quality of life were reported.

The objective of the present study is to assess the value of mistletoe extract as a complement to standard treatment (palliative chemotherapy or best supportive care) in advanced pancreatic cancer patients with regard to overall survival and health-related quality of life.

Methods

The trial is prospective, randomised, double-blind, multicentre, parallel group and placebo-controlled. In total, 290 participants are randomly assigned to placebo or mistletoe extract given subcutaneously in increasing dosage from 0.01 to 20 mg three times per week for 9 months. Stratification is performed for site and palliative chemotherapy. Main inclusion criteria are advanced pancreatic cancer and Eastern Cooperative Oncology Group performance status 0 to 2; main exclusion criteria are life expectancy less than 4 weeks and neuroendocrine tumour of the pancreas. Two ancillary studies on sub-sets of participants are nested in the trial: a biomarker study collecting blood samples and a cross-sectional qualitative study with semi-structured face-to-face interviews.

Discussion

To our knowledge, this is the first placebo-controlled randomised trial assessing the impact of mistletoe extract as a complement to standard treatment on overall survival and health-related quality of life in patients with advanced pancreatic cancer. The presented trial with its two nested ancillary studies exploring biomarkers and patient experiences is expected to give new insights into the treatment of advanced pancreatic cancer.

Trial registration

EU Clinical Trial Register, EudraCT Number 2014-004552-64. Registered on 19 January 2016.

ClinicalTrials.gov NCT02948309. Registered on 28 October 2016.

[Mistletoe in the treatment of cancer patients]

Mistletoe (Viscum album L.) continues to be the medical herb prescribed most frequently for cancer patients in German-speaking countries. Demand for this therapy often comes from patients themselves and requires careful consideration by the attending physician during consultation.In German-speaking countries, mistletoe extracts are available as approved drugs (based on monographs of the commissions C and E of the German Federal Institute for Drugs and Medical Devices). In Switzerland, treatment costs are generally covered by statutory health insurance. In Germany, coverage is limited to palliative care. In adjuvant cases, treating physicians can request coverage by the health insurance if patients suffer from side effects due to the antitumoral treatment.The spectrum of Viscum album extract includes mistletoe lectin I; II, and III, viscotoxins, flavonoids, amino acids, polysaccharides, and membrane lipids. Preclinical studies have demonstrated cytotoxic, apoptosis-inducing, and immunomodulatory effects.Many clinical studies indicate a supportive efficacy of mistletoe extracts in tumor patients, even though methodological quality is discussed controversially in many cases. Clinical data regarding effects on survival of patients is inconsistent; effects concerning quality of life as well as the tolerability of antitumoral treatments are evaluated more positively.In view of the high demand on the patient side and increasing scientific evidence, the general conditions for prescriptions should continue as well as the ongoing scientific evaluation.

Long-term survival of a patient with an inoperable thymic neuroendocrine tumor stage IIIa under sole treatment with Viscum album extract: A CARE compliant clinical case report

RATIONALE

Thymic neuroendocrine tumor (TNET) is very rare and characterized by a tendency to invade adjacent structures, frequent metastasis, resistance to therapy, and a poor prognosis. Viscum album extracts (VAE) have shown immunological, apoptogenic, and cytotoxic properties.

PATIENT CONCERNS

A 54-year-old Peruvian man was suffering from constant fatigue, cough, dyspnea, and fever for a couple of months.

DIAGNOSES

He was diagnosed with TNET (12.8 cm × 10 cm × 7 cm) stage IIIa, G1. Due to the size and extensive invasiveness (vena cava superior, also obstructing 85% of its lumen, pericardium, and pleura), the TNET was inoperable.

INTERVENTIONS

We report the case of this patient who declined chemotherapy and was treated instead with sole subcutaneous VAE 3 times per week for 85 months. No other tumor-specific intervention was applied.

OUTCOMES

Quality of life (QoL) improved substantially. The patient returned to work, and the tumor remained stable for 71 months. Thereafter, the tumor progressed, and the patient died 90 months after initial diagnosis. Besides self-limited local skin reactions around the application site, no side effects occurred.

LESSONS

This is an exceptionally good course of disease of an inoperable, large, obstructing, and invasive TNET with a reduced baseline condition (Karnofsky index: 50-60) due to pronounced symptoms. Given the considerable reduction of symptoms and improved QoL following the onset of VAE therapy and other reports describing long disease stability and improvement of the QoL using VAE in different cancer types, we presume that the VAE treatment was supportive in this case. As TNETs are rare and few trials are available, future treatments of TNETs using VAE should be carefully documented and published to help determine whether further investigation of the use of VAE in TNET treatment is worthwhile.

Aviscumine, a recombinant ribosomal inhibitor, increases the antitumor activity of natural killer cells

Aviscumine, a recombinant lectin I, has been identified as an immunomodulatory agent within a new class of ribotoxic stress-inducing anticancer substances that have demonstrated efficacy in phase I/II trials. The aim of the present study was to elucidate the presumed effect of aviscumine on enhancing human natural killer (NK) cell antitumor cytotoxicity. To measure the effect of aviscumine on human NK cell cytotoxicity, chromium-51-release assays against K-562 cells were performed with isolated NK cells from the whole blood of 34 healthy volunteers. Two effector-to-target cell ratios (12.5:1 and 25:1) were used by two independent investigators with a focus on the concentration-dependent effect (0.5 vs. 1 ng/ml aviscumine), reproducibility (first vs. second investigator) and the specificity of the effect by comparison to a heat-inactivated aliquot and interleukin 2 (IL-2) stimulation (10 ng/ml). The mediation of the effect via degranulation was demonstrated by flow cytometric analyses of CD107α expression. Statistics were performed with SPSS using Student's t-tests for normally distributed data. Aviscumine induced a significant and reproducible, concentration-dependent increase in NK cell cytotoxicity (n=22; P<0.01 for both concentrations and ratios), which was also demonstrated when administered in combination with IL-2 (n=12; 12.5:1 ratio, P<0.001; 25:1 ratio, P=0.025) and when compared with the heat-inactivated aliquots (n=12; 12.5:1, P=0.004; 25:1 ratio, P=0.007). The mediation of its effect via interferon γ degranulation was demonstrated by significantly enhanced CD107α expression (n=7; P=0.005). Taken together, the results indicate that aviscumine induced an increase in NK cell anticancer cytotoxicity. These results highlight its clinical potential as an immunostimulatory agent, particularly with regard to combined use with chemotherapeutics or immune checkpoint inhibitors. However, further studies are required.

Viscum album (L.) in experimental animal tumors: A meta-analysis

Mistletoe (Viscum album L.) has been used as complementary anticancer treatment for ~100 years. Although the clinical efficacy of mistletoe in cancer and associated survival benefits remain contested, several studies point to its effectiveness and others have reported antitumor and immunomodulatory properties. In the present review, a search was conducted for original articles reporting the outcomes of treatments for experimental animal tumors with mistletoe. The inclusion criteria were: Publication in English, from 1996 onwards and in peer-reviewed journals included in the database PubMed. The parameters analyzed were: Provenance and time of publication, rationale, methods (animal species used, mistletoe preparation, treatment protocol, tumor lineage, blinding, randomization, controls and concomitant treatments), outcomes and investigated mechanisms of action. A total of 37 studies met the inclusion criteria. The quality of the studies was adequate in the terms of sample size and use of controls, and the only animal species employed were mice and rats. However, few studies reported having performed random allocation and none reported blinding. There was wide variation in the type and preparation of mistletoe used, route of administration, regimen, tumor type and the mechanism of action assessed. A temporal trend was identified; earlier studies sought to establish the antitumor effect of mistletoe and its possible mechanisms, cytotoxicity and immunomodulation in particular, whereas the later ones tended to focus more on biologically active principles, genomics and oxidative stress. A total of 32/37 studies reported an antitumor effect, 3 of which had mixed results. A total of 2 studies did not detect any antitumor effect and a further 2 found stimulation of tumor growth in the treated groups. One study did not assess antitumor effects, investigating immunomodulation action instead. The quality of the studies was satisfactory and the majority reported positive outcomes. Nevertheless, there is a great deal of methodological heterogeneity among the studies, which precludes conclusive comparisons. Based on these results, the present authors strongly suggest developing guidelines for reporting in vivo mistletoe cancer treatment experiments.