Do Plants Get Cancer? Treating Cancer with Light and Chlorophyll

[Guest guest]

(OK, this IS novel. Not applicable to CLL, but interesting

nevertheless.)

Experimental Therapeutic

British Journal of Cancer (2003) 89, 2333-2339.

doi:10.1038/sj.bjc.6601457

Combined hyperthermia and chlorophyll-based photodynamic therapy:

tumour growth and metabolic microenvironment

D K Kelleher1, O Thews1, A Scherz2, Y Salomon3 and P Vaupel1

1Institute of Physiology and Pathophysiology, Johannes Gutenberg-

University Mainz, Duesbergweg 6 D-55099 Mainz, Germany

2Department of Plant Science, The Weizmann Institute of Science,

76100 Rehovot, Israel

3Department of Biological Regulation, The Weizmann Institute of

Science, 76100 Rehovot, Israel

Received 30 July 2003; revised 7 October 2003; accepted 8 October 2003

The effects of combined and simultaneously applied localised 43°C

hyperthermia (HT) and an antivascular bacteriochlorophyll-serine-

based photodynamic therapy (Bchl-ser-PDT) on tumour growth and

several microenvironmental parameters were examined. Rats bearing DS-

sarcomas were allocated to treatment groups: (i) sham-treatment

(control), (ii) Bchl-ser-PDT (20 mg kg-1 i.v.), (iii) localised HT,

(iv) Bchl-ser-PDT+HT. The light source used was an infrared-A

irradiator, which, by use of appropriate filters, delivered the

different ranges of wavelengths required.

Following treatment, tumour volume was monitored. The greatest tumour

growth inhibition was seen with Bchl-ser-PDT+HT, and subsequent

experiments identified the pathophysiological basis for this effect.

Red blood cell flux in tumour microvessels declined rapidly upon Bchl-

ser-PDT+HT, reaching approximately 10% of initial values by the end

of treatment. Similarly, tumour oxygenation worsened, reaching almost

anoxic levels by the end of the treatment period. Assessment of

metabolic parameters showed a pronounced increase in lactate levels

and a decrease in ATP concentrations after combined treatment.

The results presented suggest that vascular collapse and flow stasis

resulting in a deterioration of tumour oxygenation and a switch from

oxidative to glycolytic glucose turnover are key elements in the

tumour eradication seen with this novel approach in which an

antivascular PDT and HT are combined and simultaneously applied.