Homoeopathic Viscum album extract inhibits the growth of osteosarcoma cells

INTRODUCTION

Cancer remains a significant global health issue. While numerous advances have occurred in treatment methods, there is always space for a new clinical approach that can improve the patients’ health and quality of life.^[1,2] Osteosarcoma is not a common type of cancer despite being the most common primary osseous tumour. It is more prevalent in children and young adults between the ages of 10 and 30 years, but can occur in people of any age.^[3-4] Osteosarcoma most frequently occurs in the long bones of the extremities; in rare cases, it can occur in other bones like the jaw and talus.^[5,6]

For osteosarcoma, cure is achievable, but often requires aggressive surgical resection with amputation followed by chemotherapy. If a limb-salvage procedure is practicable, a course of multidrug chemotherapy precedes surgery to downstage the tumour, followed by wide resection of the bone and insertion of an endoprosthesis.^[7,8]

Viscum album (VA), a hemiparasite plant that grows in deciduous trees, is one of the research subjects in the idea of screening therapeutic plants to discover effective anticancer agents.^[9] Unfortunately, little is known about the screening of bioactive composites from parasitic plants and their possible active ingredients.^[10]

In complementary medical streams, especially anthroposophical medicine, VA extracts are used to treat cancer. As VA extracts are being investigated for their anticancer effects and improvement regarding quality of life, it opens doors for new studies with the homoeopathic version of VA as well.^[11-14]

For in vitro studies, the most used osteosarcoma cell line used is the U-2 OS, particularly because of their fast growth and high transfection efficiencies. The line was cultivated from the bone tissue of a 15-year-old girl with osteosarcoma.^[15,16] U-2 OS is widely used as an osteoblastic model for their high adherence efficiency and unrestricted cell division. These properties distinguish them from normal osteoblasts and occur mostly because of gene mutations and a collection of chromosomal abnormalities. These abnormalities cause overexpression of various oncogenes and inactivation of tumour-suppressor genes or other components of their regulation pathways.^[17,18] The aim of the present study was to evaluate the cytotoxic action of two homoeopathic medicines obtained from VA extract. The medicines used were VA ultradiluted in 10⁻³ (VAD3) and 10⁻³⁰ (VAD30) potency. The primary objective was evaluating the behaviour of these medications in cell culture followed by evaluation of their cytotoxic action.

MATERIALS AND METHODS

RESULTS

The finding of the first test was that cells of U-2 OS that was in contact with the different concentrations of VAD3 and VAD30 (10–100 μL/mL) were not viable [Table 1]. The control groups (cell culture without the homeopathic medicines) presented no alteration of viability, which means that both medicines caused considerable cell death. Even the lowest concentration (10 μL/mL) caused an intense decrease in cell viability and the IC₅₀ could not be calculated For this reason, lower concentrations ranging from 1 to 10 μL/mL (1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 μL/mL) were tested.

The MTT assay showed that the homoeopathic medicine was effective against the osteosarcoma cell lines tested. Using the new absorbance values, it was possible to calculate the cell viability and the IC₅₀ for each cell line with the VAD3 and VAD30 [Table 2].

For the homoeopathic VAD3, as observed in [Figure 1], the absorbance of the MTT reaction gradually decreased as the concentration of VA increased, indicating a lower number of living cells.

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Figure 1:

Absorbance levels obtained with the MTT test of VAD3 in U-2 OS cell line

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There was no significant difference in the analysis between the control sample and the 1 μL/mL of VAD3 sample. With the other samples tested, all of them presented a significant difference in the cell population in comparison with the control (P < 0 0001). With this result, it was possible to calculate that the IC₅₀ of the ultradiluted VAD3 in U-2 OS cells was 6 62 μL/mL.

With the ultradiluted VAD30 [Figure 2], after a 48 h incubation, the same pattern of absorbance was observed. There was no significant change with 1 μL/mL of VAD30 sample, but after 2 μL/mL, the significance in relation to the control sample was already greater (P < 0 0001). VAD30 had an IC₅₀ calculated result of 5 82 μL/mL, in which only 50% of the U-2 OS cell population survived; this implied that the cells were reduced significantly in a dose-dependent manner and the medication was extremely cytotoxic.

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Figure 2:

Absorbance levels obtained with the MTT test of VAD30 in the U-2 OS cell line

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DISCUSSION

Homeopathy is considered an important supplementary therapeutic source in cases of cancer Some in vitro validations have been made till date; for many years, the VA plant extract has been an object of scientific interest with its anticancer potential as well as its cardioprotective effects.^[19-21]

The results obtained in the present study are promising as they show the potential action of the ultradiluted VA (VAD3 and VAD30) against osteosarcoma U-2 OS cell lineage. This finding corroborates the literature regarding the cytotoxic action of VA extract.^[22] However, some studies have demonstrated side effects when VA extract is used in high dosages, including dose-dependent flu-like symptoms, fever, local reactions at the injection site and various mild unspecific effects.^[13] As little is known about the homoeopathic version, this study joins with the few existing in the literature today to reverse this scenario. Considering in vitro studies are a field of increasing interest in science, as they can show the action of the medication in cellular level with specific and direct results, our study brings a new perspective for homoeopathic science.

The predicted potential of action of this ultradiluted VA is important because it can show an indicative of concentration range that can be effective and beneficial to the patients as well. Several compounds with pharmacological properties have been found in the VA plant, among which we highlight viscotoxin and phoratoxin (both producing bradyarrhythmia and decreasing myocardial contractility) and galactose-specific lecithin I, which increases the immune response and release endorphins. The effects of VA extracts against cancer cells have been demonstrated in several instances,^[23,24] including an additive antitumor effect when used in combination with ionising radiation.^[25,26] However, further studies are needed to assess their true role in cancer treatment, as our study was not designed to go so far. Other in vitro studies should be performed to evaluate the possibility of these extracts inducing cell apoptosis as well as to determine the genomic responses to treatment with homeopathic VA.

CONCLUSION

This study brings a promising result that shows the action of VAD3 and VAD30 in the U-2 OS lineage of osteosarcoma cancer cells. This opens up the possibility of using this medicine in the treatment of these tumours; if not alone, at least in association with other medicines or techniques.