Pulsed
Field Assisted Chemotherapy
Copyright
- James E. Bare
2004
[
A short comment on this paper, as it is now the year 2026. Since it's creation,
the principles in this paper have been adopted independently by at least two
companies that are producing FDA approved devices for cancer treatment. Namely -
Therabionics and their P1 device, and Novocure and their Optune Device. What was
a theory in 2004 is now a proven method
to create enhanced treatment outcomes.
Research into the physiologic
effects of low power, pulsed electromagnetic (EM) fields, has produced a number
of important discoveries. To date, with rare exception, these discoveries at
best are investigational, and have not been applied in a clinical manner.
Much of this research material is unknown to the general practitioner,
and has not been correlated into a potentially utilizable treatment method.
This paper proposes the fusion of existing cancer chemotherapy techniques
with low power pulsed EM field research discoveries. Evidence is presented that
the sum of these combined effects far exceeds that of each method individually.
A transmitted, pulsed EM field, can
be created which will safely produce whole body permeation/saturation. Such
saturation can create an interaction of the pulsed EM field with
chemotherapeutic medications, simultaneously,
at all tumor sites throughout the body. By creating a synergism of
biochemical, electrochemical , and electronic principles, the practitioner
should be able to achieve a superior treatment outcome.
Present chemotherapy regimens are
fraught with many shortcomings. The worst of these is toxicity , which can
include permanent damage to various vital organs including the heart, lungs and
kidneys. Even without such permanent damage, short term toxicity manifests as
severe nausea, repression of the hematopoietic system,
alopecia, and many other types of physical unpleasantness. Other major
problems with chemotherapy are development of cellular accommodation ( non
responsive/refractory to treatment), patient/family mental
stress, and in many cases no
clear cut outcome other than temporary
tumor shrinkage. Actual prolongation of patient survival post treatment is all
too often a secondary consideration in the application of chemotherapy.
The great majority of cancer
research is directed not to a solution of the these problems, but rather towards
a solution to cancer. For patients,
the only reason they consent to
such abusive treatment, is that the
consequences of untreated cancer
outweigh the negative repercussions of treatment.
What is needed is a new chemotherapeutic medication which will
selectively affect cancer cells, and has
minimal side effects/toxicity.
This medication would also have
improved outcomes from treatment, and be highly resistant to cellular
accommodation . Primary importance would be directed to improved patient
survival percentages and overall length of survival. Such a medication does not
now apparently exist, and next to an outright cure, could be considered as the
“Holy Grail “ of cancer treatment. It is the contention of this paper that
it may be possible to adapt at least a few of the presently utilized
chemotherapeutic medications, to a new treatment protocol. A protocol that will
produce the effects that meet this idealized vision of cancer treatment.
This transformation of available
chemotherapeutic medications and treatment is to be accomplished via a
synergistic combination of the medication with a low voltage and low current,
transmitted pulsed electromagnetic (EM) field.
The ideal transmitted EM field is one that can couple itself energetically to
the entire body. That is, the field may be used to treat the entire body at one
time. This will ensure that wherever the medication can be delivered within the
body, treatment congruence between the field and the medication will occur.
There is considerable scientific supporting evidence for this proposal that will
be discussed in the following paragraphs.
The utilization of electrical
pulses with chemotherapy medications is not new. This technique is being
investigated and employed by a variety of researchers and cancer treatment
specialists. The primary method utilized is some variant of what is known as
electropermeabilization or as it is also known, electroporation.
An ultra short time duration, but high intensity, electrical pulse , is
applied to a tumor or group of cells to produce short duration and reversible
pores within the plasma membrane. Pores through which various ions and molecules
may be introduced into the interior of the cell. To use this technique,
a tumor site is saturated with a chemotherapy drug and then pulsed through implanted electrodes with a very short and very
intense electrical signal.
An associated technique being
utilized by some clinicians and researchers is known as EChT or Electro Chemical
Treatment of tumors. In this method electrodes are inserted into the cancer site
along with a chemotherapeutic medication. In contrast to electropermeabilization,
relatively low currents and voltages are used on the tumor site. These
voltages and currents may be applied
for many hours at a time. The
migration of charged particles in the created field is somewhat akin to
electrophoresis and has produced some excellent responses to treatment.
Many of the chemotherapeutic drugs chosen for EchT or electropermeabilization techniques belong to the class known as Alkylating agents. These compounds are electrically polarized and capable of being influenced to migrate in an electrical field vector. There are obvious and non obvious reported problems to both of these electrically based methods. These include:
1. The techniques can only be used on specific localized tumors.
2. The patient must endure the implantation of electrodes and direct injection of the chemotherapy medication. Often deep within the body.
3. The effects occur primarily between the electrodes, with very large tumors needing
multiple placement of needle electrodes. The technique cannot be utilized with
extremely small tumors. This allows small metastatic sites to escape treatment.
4. Some tissues do not tolerate the direct application of chemotherapeutic medications, and there may be collateral damage to healthy tissue.
5. With EChT, there is also metallic ion migration off the electrodes into the surrounding tissues. This can create localized areas of metal toxicity.
6.
The patient must endure the bursts of electrical current into their body
from either EChT or electropermeabilization. In
EChT, the electricity is much akin to that delivered by a muscle
stimulator. An
electropermeabilization pulse is more akin to the spark derived from an
automotive ignition coil. To use a more graphic example of what a patient
experiences, imagine having a muscle stimulator or car ignition coil attached
directly to your colon.
In defense of
electropermeabilization and EChT, both methods overcome some major problems in
traditional oral or IV chemotherapy. Through direct injection into a tumor, the
medication can be concentrated at the site of the tumor without creating whole
body toxicity. Electropermeabilization and EChT offer a method to increase drug
delivery into the cancer cells, which has brought about some very significant
responses to treatment. Further, the amount of medication necessary to produce a
toxic response within the cancer cells, is at times, significantly reduced.
EChT and Electropermeabilization
are not the methods to be utilized in this proposal . They have been discussed
only to demonstrate that there are existing
synergies between electrical fields and chemotherapeutic medications.
Concept
Discussion:
The human body ( or for that matter
any mammals body) is very complex electrically
. Each cell within the body has a particular set of electrical parameters
within which it functions. The cells of the body operate and maintain their
homeostasis at least partially
through electro chemical processes.
Electrically charged particles such as ions, and proteins,
accumulate on both sides of the various membrane interfaces of a cell,
and create an electrical potential. Normal cells and cancer cells have many
different physiologic qualities, which
include those of their plasma
membrane potential and electrochemistry. A
normal cell has a plasma membrane
potential of about 70 to 100 mv (Cone, 1970, 1975, 1985). This is equal to an
electrical potential of between 10
and 20 million volts per meter ( Brown, 1999). The mitochondrial membranes of a
normal cell maintain an electrical potential of
almost 40 million volts per meter (Brown, 1999).
When a cell becomes cancerous,
plasma membranes degenerate and depolarize
( Marino et. al. 1994 ) .More
succinctly, the electrical potential across the membrane drops drastically.
The degeneration and loss of electrical potential of the plasma membrane
in cancer allows it to
become more permeable to water, and to
certain ions such as sodium that normally are found in abundance on the outside
of a normal cell. In cancer, sodium
is allowed through the cells plasma
membrane and accumulates within the cytosol. Meanwhile the ionic elements of
potassium, magnesium , calcium, and zinc, which
are normally found inside of the cell plasma membrane, tend to migrate out of
the cytosol (Seeger and Wolz, 1990). As the
distribution of ions shift, cancer cells tend to become very electronegative,
and the tissue areas surrounding the cancer cells become quite electropositive.
This electropositivity has been used for detection of cancer (Marino, et.
al, 1994). The combined effects of the low plasma membrane electrical
potential and ionic imbalance, assists in the conversion of a normal cells
aerobic based metabolism to that of a cancer cell with
an anaerobic based metabolism. Conversion to anaerobic glycolysis
(fermentation) as a primary mechanism for energy production results in excessive
accumulation of organic acids and acidic pH alterations in cancerous tissues (Seeger
and Wolz, 1990).
The loss of electrical potential
across a cancer cells plasma membrane is the foundation upon which this proposal
is based. The application of an
artificially created electrical field of a
few tens of millivolts at the plasma membrane of a cancer cell will create an
electrochemical imbalance of the cell.
An imbalance which this proposal intends to exploit.
Ions and molecules ( chemotherapy medications) enter cells through a variety of different methods. These methods include ion gating, osmosis, and endocytosis. In a normal cell, these mechanisms are all driven by cellular energetic pathways. Ion Gating and Osmotic methods are capable of only passing small ions through the cell plasma membrane. Endocytosis, can pass large macromolecules such as sugars, and most importantly medications. These three methods of transport can be artificially mediated and elicited by the presence of an external pulsed electrical field. (Teissie and Tsong 1981, Petrov and Mircevova, 1986 , Rosemberg and Korenstein ,1997 ) When so accomplished they are known as Voltage Dependent Ion Gating, Electro Osmosis, and Electro Endocytosis. By inducing these electrically driven methods of transport, pulsed electrical fields are capable of producing disruption of the cancer cells electro chemical balance and function ( Panagopoulos, Karabarbounis and Margaritis, 2002).
Electro endocytosis is of
significant interest to this proposal. Endocytosis is a process whereby the cell
plasma membrane invaginates and surrounds a large macro molecule. This piece of
plasma membrane then closes off to form a vesicle which transports the molecule
within the cell. The reverse process is known as exocytosis, whereby the empty
vesicle is transported back to the plasma membrane. The vesicle then opens, and
rejoins the plasma membrane. The
process of endocytosis must be balanced to some degree with the process of
exocytosis. If an extreme excess of endocytosis
in relation to exocytosis occurs, a possible compromise of the cells plasma
membrane may ensue.
It is well known that at very high
electrical field strengths, a process known as vesicle
electroformation occurs. This process can create extremely large or macro
size vesicles out of bilayer lipid membranes. A high electrical field strength
dependent process is not the mechanism this proposal seeks to utilize.
Rosemberg and Korenstein ( 1997)
have shown that the process of electro endocytosis can occur at very low
field strengths. They found it possible to incorporate molecules in the 1-2000
kD range into 85% of the cells used in their test.
Other researches have supported this finding. The necessary field
strength can be as low as 20 V/cm or a transmembrane potential of 6mv ( Teissie
& Tsong, 1981). Electrically
polar and nonpolar chemotherapeutic
molecules have been utilized with very low electrical field strengths to produce
highly significant positive treatment outcomes. Entin, et.
al. (2003) , used fields of 40V/cm (12
mv added transmembrane potential ) with Bleomycin, Taxol , and Cisplatin in
treatment of mice inoculated with melanoma cells. A low voltage
enhancement was also reported by Miyazaki, et.
al. (2003). Mice inoculated
with Colon cancer cells were given intratumor injections of Bleomycin and
exposed to fields of from 50 to 150V/cm . The use of
chemotherapeutic medications with electrical fields can result in
enhanced cellular sensitivity to the medication. Gray , et.
al. (2000) found severe over
dosage reactions to Adriamycin (ADM) occurred when ADM was administered to
animals kept in a static but very intense electrical field .
Cisplatin and it’s immediate
family of molecules acts directly upon DNA.
It has been used successfully in the combined treatment of
B-16 melanoma bearing mice
with low ( 20-100V/cm) field strength ( Entin et.
al., 2003). It seems apparent
that not only will the presence of cis-platinum type molecules within a cancer
cell be advantageous, but so would a simultaneous stimulation of the activity
level of the cells DNA. Cancer cells go through periods of rest and activity and
most chemotherapeutic drugs are primarily effective against rapidly dividing
cells. Application of chemotherapeutic medications is often timed to a perceived
interval of genetic/cellular activity. The usage of low voltage pulsed
fields seems to create an artificial “window”
of activity. Low voltage pulsed
electrical fields act not just upon the ability of a cell to aid molecular &
ionic transport, they also act upon the cells DNA. Binderman, et.
al.(1985) found that at between 13 to 50 V/cm , cell cultures of skeletal
origin would immediately show changes in cyclic AMP levels and enhanced DNA
synthesis . Blank and Soo ( 1997 )
reported a frequency dependent
effect on Na, K-ATPase enzyme activation in fields of from 3- 3000 Hz. Pulsed EM
fields have been linked not just to enzyme reactions but also to increased
transcription rates for specific genes. Pulsed EM fields act directly on signal
transduction pathways and with electrons in DNA to stimulate biosynthesis (
Goodman and Blank 2002).
Chemotherapy cellular resistance is
the most common cause of treatment failure and has several different etiologies.
The most ubiquitous method of resistance to treatment is that of
activation and expression of energy dependent transporters that literally remove
the medications from the cells ( Gottesman 2002). The medication, due to the
action of transporters, is not
allowed to accumulate to a toxic level and cannot perform it’s assigned task.
Even though small amounts of chemotherapeutic drugs do enter resistant
cancer cells, the drugs biochemical
action is thwarted. It is thought that the primary action of chemotherapeutic
drugs is the initiation of apoptosis. Apoptosis is at least partially mediated
by the behavior and chemical signals produced by the mitochondria. The
mitochondria of malignant cells are electrochemically different from those of
normal cells. This electrochemical difference acts to block mitochondrial
response to the medication, and thwarts the apoptotic cascade.
The plasma membrane potential of
mitochondria in cancers cells has been found to be elevated, in one case it was
approximately 60 mv higher than that of control epithelial cells
( Modica-Napolitano and Aprille 1987 ).
Elevated mitochondrial membrane potential coincides
with Cisplatin resistance in some cancer cell lines ( Dorward and Singh
1996). The high transmembrane
potentials of mitochondria are created by a relative electropositivity of the
outer membrane and a high negativity of
the inner membrane ( Johnson , et. al.
1981). Mitochondrial based apoptotic
mechanisms require that the plasma membranes of mitochondria depolarize,
resulting in diminution of the transmembrane potential ( Mayer and Oberbauer
2003). Due to their elevated electropotential, mitochondria of
cancer cells are going to have to
undergo a much greater fall in electrical potential than a normal cell to
initiate apoptosis. Further, formation of mitochondrial permeability transition
pores ( a key factor in the initiation of mitochondrial based apoptosis) is
inhibited as pH decreases (Nicolli , et.
al. 1994).
There are other inhibitors of treatment response within cancer cells. The majority of solid tumors show some if not total resistance to chemotherapy. This resistance is mediated by a local stress response to the microenvironment. When solid tumors are subjected to local conditions of hypoxia, acidic pH and low levels of glucose they react by stopping division. When cell division is arrested in this manner, chemotherapeutic medications become ineffective, that is they fail to induce apoptosis. ( Tomida and Tsuruo 1999 ). In summary, cancer cells are at least partially self protected against chemotherapy initiation of apoptosis through their electrochemistry.
Pulsed
Field Correction of Drug
Resistance:
Correction of cellular stress factors, inhibition of intercellular drug transporter mechanisms, excess acid production, and excess mitochondrial membrane potentials, may be possible through the application of external pulsed EM fields.
Rosemberg
and Korenstein ( 1997 ) found that
low voltage induced electro endocytosis could be used to incorporate
polysaccharides and
-
galactosides into cells. A confirmation of this effect was presented by Rols,
et. al.( 1995) . When stressed by hypoxic conditions, cancer cells produce
compounds that create neoangiogenesis. They also produce more hypoxia inducible
factor 1 (HIF1) , increase
expression of hypoxia regulated genes , and
metabolically shift to utilize the oxidizing
ability within the fatty acid synthesis pathway ( Hochachka, et. al. 2002 )
. Angiogenic responses to
hypoxia can lead to increased tumor growth , increased metastasis and poor
treatment outcomes ( Duffy, et. al. 2003). Through
the application of pulsed EM fields it
may be possible to circumvent these
stress responses to hypoxia. Di
Carlo, et.al. ( 2000), found that EM
field exposures protected chick embryo’s from hypoxic insult.
More definitively it was found that EM fields could be used to induce
increased heat shock protein 70 (hsp70) levels ( Han,et.
al. 1998, Carmody, et. al. 2000 ). Hsp70 plays an important part in the
protection of tissues to hypoxia ( Rafiee, et. al. 2003 ). Overproduction of
hsp70 has been found to protect
cancer cells from apoptosis following irradiation and chemotherapy
(Witkin, 2001). This must be judged against the consequences of a hypoxic
response. The expression of hsp 70
is key to preventing some of the sequences that lead to hypoxic response.
More importantly, hsp70 has been linked to anti cancer immune system
responses. Apoptosis can result in an immunogenic or non immunogenic response.
The immunogenic response is dependent upon the presence of hsp70. Stressed
cancer cells express hsp 70 on their plasma membranes , and can initiate an
antitumor response by the immune system ( Feng, et.
al. 2003). This response can be significant.
Mice were inoculated with Colon 26 cells and then treated with EChT and
Bleomycin. An 80 to 100 % response rate occurred. When the same mice were
reinoculated with Colon 26 cells, the mice rejected the cells and no tumor
growth was noted. Injection of a different cancer produced tumors in these same
mice (Miyazaki et. al. 2003 ). It
has been found that immunogenic response to necrotic and
apoptotic tumor cells can be
equivalent (Kotera et. al. 2001)
To clarify, the presence of pulsed
EM fields may inhibit many of the undesirable cellular metabolic responses of
cancer cells to hypoxia. These responses include; generation of hsp70,
inhibition of expression of HIF1, diminish the production of angiogenic proteins, initiation of
an anti cancer immune response, and possibly inhibit the activity of
the FAS to reduce cellular growth rates.
This proposed outcome from the use of pulsed EM fields to inhibit
angiogenesis and tumor growth is supported in the literature. Pulsed EM fields
were found to inhibit tumor growth with a reduction in the extent of
vascularization and increased areas of tumor necrosis compared to controls (
Williams, et. al.
2001).
In
a cancer cell, Na+ ions accumulate inside the cell and K+
ions accumulate outside the cell. Modification and
reversal of the local ionic
concentrations and can be created by an external AC field. ( Teissie and Tsong
1981). Further , elevated pHi will increase the delta pH across the plasma
membrane. It has been found that as a Multi Drug Resistant (MDR)
protein is expressed, the delta psi
or plasma membrane potential decreases ( Roepe, et. al. 1993). The
presence of a pulsed field will circumvent the fall in plasma membrane
potential. The energy within a
pulsed EM field is capable of being absorbed by plasma membranes at least
partially through the process of electro conformational coupling (Tsong,, et. al.,1989)
Once absorbed, this energy may be converted to the chemical bond energy
of ATP or to the potential energy
of concentration gradients ( Tsong, et. al.,
1989, Timashev 1981) . EM pulse responses of cellular membrane systems are
frequency dependent. This
response has been shown in several membrane enzyme systems ( Markin and Tsong
1991, Luchian, et. al., 2002,
Ruiz-Gomez, et.al., 2002,
Gluck et.al. 2001). Frequencies can also be utilized to affect cell
division and growth. Kirson et al.,2004 ,found that low intensity
frequencies in the 100 KHz to 300 KHz produced
an inhibitory effect on a variety of human and rodent cell tumor lines. This
effect was non thermal, and acted through both arrest of cell division and
destruction of cells undergoing division.
Movement
of ions and molecules across the mitochondrial membranes is normally
accomplished by a chemiosmotic mechanism that is free electron dependent. It is
possible that the presence of a pulsed field
could supplement, drive, or supplant this mechanism and
affect the electropotential gradient of mitochondria. This may result in
a diminution of the outer membranes electropositivity, allowing the Voltage
Dependent Anion Channels ( VDAC) to
open. As the electropotential of the mitochondrial membranes become depolarized
the probability of Mitochondrial Permeability Transition Pore ( MPTP ) formation
increases. (Petronilli, et. al., 1994). Formation of MPTP’s is a necessary
precursor to the initiation of mitochondrial based apoptotic mechanisms. Similar
pulsed fields gradients should act to inhibit the expulsion of drug molecules
from the cell. The transporters will have to work against an artificially
created concentration gradient that seeks to actively bring ions and molecules
into the cell.
From a practitioners viewpoint any
instrument that might generate a pulsed EM field must conform to several
criteria. Primarily, the device must be safe for the patient, and application
must be consistent from patient to patient. Secondarily the device must be easy
for the practitioner to utilize.
Presently, there is not such a clinical device approved for use by the US FDA.
Countries such as Canada have approved pulsed
EM field devices that meet this criteria. Below is a picture of a type of device
that will produce the necessary non thermal pulsed EM field. A variant of this
instrument is presently approved by Health Canada as a transmitted field TENS
device for the control of pain. Effective range is approximately 6 meters,
typical treatment distance of the patient from
the device is 2 meters.
Summary
:
The application of a transmitted
pulsed EM field of low potential makes it possible to modify the
electrochemistry and physiology of cancer cells.
Cellular membrane systems and cellular mitosis
are frequency responsive, and can be influenced by pulsed EM fields of
varying frequency sequences and duration. Frequency
sequences can be created to selectively encourage different metabolic responses.
The presence of the external field will produce a
change in transmembrane potentials . This change in potentials will
create osmotic, ion gating, and endocytotic effects at the cells plasma membranes.
Internal and external actions of the field will result in ion/molecular
transport, reversal of cellular stress factors, interfere with angioneogeneis,
increase DNA transcription rates,
produce an immune response, and
cause inhibition of drug resistance
mechanisms
It is the hypothesis of this paper
that the totality of these effects will be enhanced transport of
chemotherapeutic medications into the cells,
retention of the medications to achieve high concentration levels,
and increased responsiveness
to the utilized medication . As the concentration of the medication increases in
conjunction with the pulsed field altered cancer cell metabolism, apoptotic
effects should become predominant. Transmitted
pulsed EM fields when used in
conjunction with chemotherapeutic medications will; decrease the treatment
dosage substantially, produce
an enhanced response to treatment, and have minimal to no toxic side
effects.
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