ACTA SCIENTIFIC MEDICAL SCIENCES (ISSN: 2582-0931)

Volume 3 Issue 8 August 2019

Review Article

An Insight into Cancer and Anticancer Drugs

X Raichel Nivetha1, M Jeslin Jeba Soundari1, MSA Muthukumar Nadar1, D Premnath1, Paulraj Mosae Selvakumar2*
and Ruey-yi Chang3
1
Department of Biotechnology, Karunya Institute of Technology and Sciences (Deemed to be University), Coimbatore, Tamilnadu, India
2
Science and Math Program, Asian University for Women, Chittagong, Bangladesh
3
Department of Life Sciences, National Dong Hwa University, Hualien, Taiwan, China
*Corresponding Author: Paulraj Mosae Selvakumar, Science and Math program, Asian university for women, Chittagong, Bangladesh.
Received: June 03, 2019; Published: July 04, 2019
DOI: 10.31080/ASMS.2019.03.0340

Abstract
Cancer is one of the most common and widespread diseases in the human population and has been reported to be the second
major cause of death globally. The World Health Organisation states that about 200 different types of cancers have been identified
worldwide, each of which requires unique approaches for treatment. It also records that 1 in every 6 deaths in the world are due to
cancer which clearly evidences for the inevitable necessity for the control and cure of cancer. Unlike normal cells, cancer cells un-
dergo uncontrollable cell division and each division leads to multiple mutations in a continuous fashion. There are various strategies
towards targeting cancerous cells. With the advent of conventional therapies, various chemical derivatives are being used as anti-
cancer drugs. This article reviews on the various approaches put forth in the fight against cancer through cancer therapies and drug
designing by identifying potent targets. Here we will be discussing about the history of cancer and its advances towards development
of anticancer drugs from tip to toe.
Keywords: Cancer; Anticancer Drugs; Carcinogen; Cisplatin; QSAR

Introduction
There are over 200 different types of cancer diseases that have
been identified worldwide with 9.6 billion deaths recorded in the
year 2018 alone. The annual survey taken by the World cancer re-
search fund in the year 2018 states that over 8,218,216 cases are
diagnosed with cancer of which lung cancer tops the table with
over 2 million cases [1], followed by breast cancer and colorectal
cancer.

As we all know that cells are the basic unit of life, a healthy per-
son’s body cells divide continually and replace the dead ones in a
controlled manner. The dead cells are replaced by the healthy ones
by either shedding away (in case of skin) or getting itself buried
inside the bone marrow which is the graveyard of RBCs (erythro-
Figure 1: Normal cell division Vs. Cancerous cell division.
cytes) or get carried away along with the excreta. However, it is not
so in the case of cancerous cells. Cancer cells grow rapidly and un-

Citation: Paulraj Mosae Selvakumar., et al. “An Insight into Cancer and Anticancer Drugs". Acta Scientific Medical Sciences 3.8 (2019): 32-43.
An Insight into Cancer and Anticancer Drugs

33

controllably in a continuous fashion (Figure 1). While a normal cell these humors were balanced, a person was healthy. However, im-
stays in a human on an average of 7 to 10 years, cancerous cells ex- balance in any of these humors may cause disease. This theory was
ceeds the count (i.e.)cancer cells are immortal [2]. Moreover, these pioneered by the Romans and remained standard throughout the
cells do not die but accumulate in our body causing undesirable middle ages for over 1,300 years. During this period, the study of
and serious health hazards [3]. the body, including autopsies, was banned for religious reasons,
which limited the progress of medical knowledge [6]. This theory
Cancer cells can develop from any part of the body. Some of the was then followed by the Lymph theory which arose in the year
cancer cells show visible growths called tumors. These tumors 1540 as a result of the failure of Andreas Vesalius to confirm the
are a group of cells that show abnormal behaviour and can travel existence of black bile of the humoral theory [7] .The lymph theory
through the blood and lymphatic system by breaking through them proposed that cancer was developed by one of the fluid that runs
and spread to the entire body system. Metastasis is a terminology through our body called lymph. This theory was supported in 17th
given to such type of cancer cells that multiply and give rise to new century by Stahl and Hoffman who hypothesized that cancer was
tumors. But, there are other forms of cancers such as leukaemia, composed of lymph, a fluid in our body that is constantly thrown
which does not develop tumors. As tumors are visible, they can be out by the blood [8]. John Hunter, the Scottish surgeon from the
diagnosed easily when in comparison with non-tumorous cancer 1700s, agreed that tumors grow from lymph constantly released
cells. It is therefore, the responsibility of each and every individual from blood [23]. Lusitani and Tulp revealed the contagion theory
to diagnose themselves periodically and thereby alleviate the risks in 1649 and 1652, respectively. They proposed that cancer patients
in its initial stage itself. should be secluded outside cities and towns, in order to prevent
the spread of cancer [6]. The blastema theory that emerged in 1838
The UK cancer research organisation states that not all cancers demonstrated that cancer is not made by lymph but by cells. This
are malignant, and that over 50% of cancer diagnosed patients theory was proposed by a German pathologist Johannes Muller, and
have lived for more than 5 years. It also states that some cancer he believed that cancer cells did not come from normal cells. Muller
patients had survival rate of more than 90% [4]. One should follow continued that cancer cells developed from budding elements
a healthy lifestyle and undergo proper health check up that can (blastema). His student, Rudolph Virchow, concluded that all cells,
help us overcome this dreadful disease. As there are various ap- including cancer cells, are derived from other cells. The chronic ir-
proaches that are being applied towards combating cancer which ritation theory proposed by Virchow stated that chronic irritation
works out to be positive, there has been a huge change-over in the was the root of cancer, but he believed that cancers “spread like a
mindset of people towards the perspective of cancer which is a liquid” [6]. But In the 1860s, German surgeon, Karl Thiersch, dis-
healthy sign of getting rid of this disease. proved the theory by stating that cancers metastasize through the
spread of malignant cells and not through some unidentified fluid.
History of cancer Regardless of the advances in the understanding of cancer, from the

The word cancer was initially coined by the “Father of Medi- late 1800s till the 1920s, trauma was believed to cause cancer. The

cine”, Hippocrates, as carcinos and carcinoma which describes ul- first insight towards the cause of human cancer happened in the

cer causing and non-ulcer causing tumors. Later, it was modified 18th century when John Hill found that the reason behind nasal

by Celsus, a Roman physician, who termed it as cancer [5]. The polyps was due to the use of snuffs.

chapter of cancer begun as early as in 1600 BC when Edwin Smith

Similarly Percival Pott and Bernardin Ramazzini figured out that
papyrus, an Egyptian medical text which dates to the 16th and the
soot from Chimney and certain reproductive factors are associat-
17th dynasties of the Second Intermediate Period in ancient Egypt.
ed behind the cause of scrotal and breast cancer respectively [1].
This papyrus contained speculations that witnessed cancer to be
This belief was maintained in spite of the failure of injury to cause
a deadly serious disease associated to ‘the curse of the Gods’ [6].
cancer in experimental animals. The infectious disease theory was
proposed by Zacutus and Nicholas, the doctors in Holland. These
It was also at this period wherein several theories were put
doctors believed that cancer was contagious. They made this con-
forth in the view point of cancer. Firstly, the Humoral theory pro-
clusion based on their experiences with breast cancer in members
posed by Hippocrates believed that the body had 4 humoral bodily
of the same family circle.
fluids namely blood, phlegm, yellow bile, and black bile. When

Citation: Paulraj Mosae Selvakumar., et al. “An Insight into Cancer and Anticancer Drugs". Acta Scientific Medical Sciences 3.8 (2019): 32-43.
An Insight into Cancer and Anticancer Drugs

34

of cancerous cells, instead of following this property, they replicate

uncontrollably thereby promoting cancer progression.

Another characteristic of cancer cells is their replicative immor-

tality, a term for describing uncontrollable cell division. They can
divide multiple times than a normal cell of the body [12]. In gen-
eral, human cells proliferate by a concept known as “The Hayflick’s
limit”. The Hayflick Limit is a concept that explains the mechanisms
behind cellular aging. The conception states that a traditional hu-
man cell will solely replicate and divide forty to sixty times before it
cannot divide any more, and at last, these cells grow old and even-
tually break down by programmed cell death or apoptosis [13].
Cancer cells however resist contact inhibition by growing uncon-
trollably and this is termed as “replicative immortality”.

Cancer cells will divide for the most part by expressing a link
protein such as an enzyme, which reverses the wearing down of
chromosome ends that normally happens during each cell division
[14]. A telomere is a region of repetitive sequences at each end of
eukaryotic chromosomes in most of the eukaryotes that protect the
end of the chromosome from DNA damage or fusion with neigh-
boring chromosomes [15]. Telomerase is the enzyme responsible
for maintaining telomere length by the addition of guanine-rich

Figure 2: Timeline on various cancer theories of the past [5]. sequence repeats. In most tumor cells, the replication potential is
unlimited. The role of maintaining telomere length is poorly stud-
ied because of the inability of DNA polymerase to completely copy

The 17th and 18th centuries were the time when people believed DNA at the ends of chromosomes; therefore, approximately 50

that cancer was contagious although it’s not so. We now know that nucleotides are lost during each cell cycle, which results in gradual

certain viruses, bacteria, and parasites can augment a person’s risk telomere length shortening [16].

of developing cancer [6].

An error in DNA repair may attach a proto-oncogene to part of

Rationales for cancer progression a different gene, producing a “combo” protein with unregulated
activity [17]. Activated oncogenes cause apoptotic cells to survive
Cancer progression may be due to diverse reasons. Its develop-
and proliferate instead [3]. Genes that ordinarily block cell cycle
ment and progression are sometimes joined to a series of changes
progression are referred to as tumor suppressors. Tumor suppres-
within the activity of cell cycle regulators. The various reasons for
sors stop the formation of cancerous tumors once they are oper-
the development and progression of cancer are discussed below.
ating properly, and tumors may form when they mutate so they
no longer work. One of the foremost vital growth suppressors is
One reason may be due to loss of contact inhibition in cancer
growth macromolecule p53, that plays a key role within the cel-
cells that reflect the loss of a mechanism that normally maintains
lular response to deoxyribonucleic acid harm. p53 acts primarily at
tissue balance in our body [10]. Contact inhibition is a regulatory
the G1 checkpoint (controlling the G_11), where it blocks cell cycle
mechanism that functions to keep cells growing into a substrate.
progression in response to damaged DNA and other unfavorable
If the cell occupies the entire substrate, the normal cells will stop
conditions [11].
replicating. As motile cells come into contact in confluent ones,
they exhibit decreased mobility and mitosis [11]. However in case

Citation: Paulraj Mosae Selvakumar., et al. “An Insight into Cancer and Anticancer Drugs". Acta Scientific Medical Sciences 3.8 (2019): 32-43.
An Insight into Cancer and Anticancer Drugs

35

Types of cancer For a cell to divide into 2 daughter cells, it has to follow a series
of cyclic processes commencing from G0 phase and followed by
The American Cancer Society 2019 survey stated that the esti-
G1→S→G2→M, which is commonly known as the cell cycle wherein
mated annual incidence for 2019 had to be 40,000 cases or more.
cyclins and CDKs play a major role in triggering each phase. In or-
The most widespread type of cancer on the list is breast cancer,
der to ensure the correctness of the cell cycle process, there are
with 271,270 new cases expected in the United States in 2019. The
check points at G1, G2 and M phases respectively [21]. As far as the
next most typical cancers are carcinoma and prostatic adenocarci-
CDKs and cyclins are in a limited amount, the progression of cells
noma. For 2019, the calculable variety of latest cases of carcinoma
is limited too. But if there is any kind of increase in the concentra-
and body part cancer are 1,01, 420 and 44,180, respectively, add-
tion of these enzymes, the progression augments. The mechanism
ing to a total of 145,600 new cases of colorectal cancer [16].
of cancer is mainly due to genetic mutation which alters the en-
zyme concentration [22]. This increase may be due to four main
Type of cancer Expected Cases Expected deaths factors namely point mutation, DNA amplification, chromosomal
Bladder 80,470 17,670 rearrangement and epigenetic modifications such as methylation
Breast (Female - 268,600 - 2,670 41,760 - 500 or acetylation [23]. Uncontrolled cell growth is caused by the acti-
Male) vation of oncogenes such as RAS gene and MYC gene or by the in-
Colon and Rectal 145,600 51,020 activation of tumor suppressor genes such as p53, APC, BRCA 1/2,
(Combined) and these oncogenes are the reason why the cancer cells bypass
Endometrial 61,880 12,160 these three checkpoints too [24].
Renal 73,820 14,770
Leukemia (All Types) 61,780 22,840 WHO states that the first critical step in the management of
Liver and Intrahepatic 42,030 31,780 cancer is to establish the diagnosis based on pathological examina-
Bile Duct tion. Obtaining a tumor sample is achieved through performing a
Lung (Including 228,150 142,670 biopsy or aspiration that may require an intervention such as an
Bronchus)
image-guided procedure or endoscopy [1]. However the common
Melanoma 96,480 7,230
approaches towards cancer diagnosis involve physical examina-
Non-Hodgkin 74,200 19,970 tion, lab tests, imaging tests and biopsy [25]. During physical exam-
Lymphoma
ination, the examiner may look for abnormalities, changes in skin
Pancreatic 56,770 45,750
color, organ enlargement; lab tests involve urine and blood tests
Prostate 174,650 31,620
to check for blood cell count; imaging tests embody CT (Computed
Thyroid 52,070 2,170 Tomography) scan, bone scan, Magnetic resonance imaging (MRI),
antilepton emission picturing (PET) scan, ultrasound and X-ray, bi-
Table 1: Table showing most common types of cancer
opsy where cell samples are collected for testing below the micro-
recorded in the year 2019.
scope to, observe cell morphology [26].
Courtesy: American Cancer Society: Cancer Facts and Figures
2019. Atlanta, Ga: American Cancer Society, 2019 [1]. Carcinogens
A carcinogen is any substance that can increase the incidence of
The major types of cancer are carcinoma, sarcoma, melano-
neoplasm when compared with the occurrence in suitable controls
ma, lymphoma, and leukemia of which carcinomas are the most
in a defined test organism (Comprehensive Toxicology, 2010). Ac-
commonly diagnosed cancers that originate from the skin, lungs,
cording to the International Agency for Research on Cancer (IARC),
breasts, pancreas, and other organs and glands. Lymphomas are
a carcinogen is defined as a driving force that increases the risk of
cancers that arise from lymphocytes. Leukemia is a term used for
cancer [27]. It is believed that chemicals constitute the most di-
blood cancer that doesn’t usually form solid tumors. Melanomas
verse group of carcinogens [28]. IARC classifies chemicals on their
are skin cancers and sarcomas are relatively uncommon tumors
basis of their carcinogenicity into four main groups (Figure 3).
that arise in bone, muscle, fat, blood vessels, cartilage, or other soft
or connective tissues of the body [20].

Citation: Paulraj Mosae Selvakumar., et al. “An Insight into Cancer and Anticancer Drugs". Acta Scientific Medical Sciences 3.8 (2019): 32-43.
An Insight into Cancer and Anticancer Drugs

36
Anticancer drugs and their mechanism
An anticancer drug is a molecule that is effective in the treat-
ment of malignant or cancerous disease. There are many major
categories of antineoplastic drugs that hold alkylating agents, anti-
metabolites, natural products, and hormones and drugs that dem-
onstrate anticancer activity and used in the treatment of malignant
disease. The term chemotherapy is frequently related to the use
of anticancer drugs, though it more accurately refers to the use of
chemical compounds that treat disease generally [34].
Figure 3: The four groups of carcinogens classified under IARC.
The early period of the twentieth century was the time when
chemotherapy came in to picture. The famous German chemist Paul
Up to 4,000 chemicals have been identified in tobacco smoke Ehrlich who pioneered drug development coined the term "che-
thus far of which more than 70 chemicals are known to cause, ini- motherapy” to treat infectious diseases by the use of chemicals and
tiate or promote cancer [29,30]. As we all know that tobacco is a was the first person to put forth the effectiveness of animal models
potent carcinogen, it is classified under Group 1 carcinogen [40]. A to display a series of chemicals for their activity against diseases
carcinogen is termed genotoxic if it binds to the cytoplasmic DNA that had a major implication on cancer drug development [35]. In
which may cause genetic alterations due to DNA mutation [28]. 1908, he used rabbit model for treating syphilis that led develop-
Most of the carcinogens enter as inactive compounds as has to be ment of arsenicals to treat this disease. He also worked on treating
activated by enzymes [32]. Not all carcinogens require metabolic cancer additionally; however, it wasn’t that successful [35]. The
activation in order to induce cancer. These directly acting carcino- period of cancer chemotherapy thus arose in the 1940s with the
gens are carcinogenic at multiple sites which include agents such first use of nitrogen mustards and folic acid antagonist drugs [36]
as epoxides, mustard gases so on and so forth [33]. that served as a model for various alkylating agents and killed rap-
idly growing cancer cells by damaging their DNA [6]. The targeted
NH2 therapy revolutions consequently embarked thereafter, but many
of the early traditional principles are still being followed [36].
CH2
O
Food Abruptly after the discovery of nitrogen mustard, Sidney Far-
preservatives ber, a pathologist from Boston identified that aminopterin, a folic
Acrylamide
Benzo(a)pyrene acid similar vitamin was fundamental for DNA metabolism [37].
Aminopterin and amethopterin (also known as methotrexate) are
H2N O the analogues that blocked a critical chemical reaction needed for
N DNA replication. The research concluded that antifolates could
Cigarette smoke
suppress proliferation of malignant cells, and re-establish normal
Nitrosamine bone-marrow function. In 1947, Babe Ruth [38], a Nasopharynx
cancer victim, became one of the first human subjects of teropterin
Benzene (an aminopterin analogue) administration. Dr. Richard Lewisohn
NH2 of New York treated the patient with that drug, and after several
H2N months, Ruth's condition improved. However, she died the follow-
H2N NH2
ing year [25]. The National Cancer Institute in 1956 discovered
Dyes that methotrexate alone could cure choriocarcinoma, a germ-cell
Benzidine malignancy originating in placental trophoblastic cells [39]. Since
Phenylene diamine then, other researchers discovered drugs that block different func-
Industries SiO2 Mg3(Si2O5)(OH)4 tions in cell growth and replication and the era of chemotherapy
started so.
Silica Asbestos

Table 2: Some of the common carcinogens used in different The theory of using adjuvant therapies to supplement primary
industries (Courtesy: PubChem). surgery evolved in the middle of the 20th century where Gianni

Citation: Paulraj Mosae Selvakumar., et al. “An Insight into Cancer and Anticancer Drugs". Acta Scientific Medical Sciences 3.8 (2019): 32-43.
An Insight into Cancer and Anticancer Drugs

37

Bonadonna and his colleagues from the Instituto Tumori in Italy

in 1973, conducted a trial that demonstrated more constructive
survival outcomes which added on to use of Cyclophosphamide
Methotrexate Fluorouracil (CMF) after the initial mastectomy.

Adjuvant systemic therapy and radiotherapy are often given

following surgery for many types of cancer, including colon can-
cer, lung cancer, pancreatic cancer, breast cancer, prostate cancer,
and some gynecological cancers. Some sorts of cancer fail to profit
from adjuvant medical care, however. Such cancers include urinary
organ cell cancer, and certain forms of brain cancer. Radiotherapy
or systemic therapy such as chemotherapy, immunotherapy or bio-
logical response modifiers or hormone therapy are the commonly
given adjuvant therapy before cancer surgery.

The use of combination therapy to treat cancer was initiated

within the 60s by treating infectious disease employing a combina- Figure 4: Schematic representation of common
tion of antibiotics to cut back the chance of resistance. The therapy anticancer drugs and their target site [43].
worked for the treatment of cancer as well. Using this approach,
cancers that had previously been almost universally fatal such as
acute lymphocytic leukemia and Hodgkin’s lymphoma became cur- Recent drug delivery process
able. Since then, combination chemotherapy has been accepted to
Recently, several therapeutic approaches have been developed
be the treatment of many other cancers as well [40]. Combination
to target the immune cells and inflammatory cytokines. The prime
therapy gained momentum in cancer studies and more advanta-
aim of all these strategies is to enhance the response of the im-
geous than sequential therapy in the recent years, with various
mune system towards inflammation and cancer [44]. Variety of
studies demonstrating higher response rates with combinations of
nanoscale compounds based on synthetic polymers, proteins, lip-
drugs compared to mono therapies, and the FDA recently approv-
ids, and organic and inorganic particles have been employed for
ing therapeutic combination drugs that confirmed superior safety
the advancement of cancer therapeutics [45]. Zero dimensional
and efficacy to mono therapies [39].
(0-D) fluorescent nanoparticles, such as quantum dots (QDs), have
been materialized to be one of the most promising nanoparticles
Oncology clinical trials proved to be the cornerstone for im-
for targeted and traceable drug delivery systems [46]. Advances in
proving outcomes for individuals at danger living with cancer [40].
the field of nanomedicine include “smart” drug delivery includes
A clinical trial is a type of patient-based clinical research study
multiple levels of targeting and extended-release drug-delivery
which potentially allocates a participant, known as a human sub-
systems that provide further techniques of overcoming limitations
ject, to one or more biomedical or behavioral interventions to ex-
associated with traditional cancer therapy. In recent times, the idea
amine health-related outcomes [41]. Cancer patients take part in
of merging smart drug delivery with extended-release has paved
clinical trials to promote experimental treatments themselves, and
way in developing highly efficient nanoparticles with improved de-
to aid scientists comprehend their diseases to develop treatments
livery, bioavailability, and safety profiles [47].
for other patients. The participation confronts include access is-
sues like inclusion and exclusion criteria or country of residence, QSAR studies
and an often underestimated impact on a psychosocial, financial
Quantitative structure-activity relationship (QSAR) studies are
and physical stage [42].
essential to be understood when a protein is the target and there
is a need to find a suitable molecule, which can curb the activity of
The activities of various anticancer drugs and their target sites
target. QSAR existed even before computers became popular, nev-
are mentioned in figure 4, and a brief description of certain com-
ertheless, with the ease of computers and databases QSAR acts as
mercially important drugs are mentioned in table 2 respectively.

Citation: Paulraj Mosae Selvakumar., et al. “An Insight into Cancer and Anticancer Drugs". Acta Scientific Medical Sciences 3.8 (2019): 32-43.
An Insight into Cancer and Anticancer Drugs

38

S. No Name of the drug Nature Other names Structure and property

1. Aminopterin antineoplastic Aminopteridine, N N NH2

Aminopterine, APGA, NH N
N
Minopterin O
NH2

HN O

OH

HO

An Enzyme inhibitor that binds with dihydrofolate reduc-

tase and blocks tetrahydrofolate synthesis.
2. Methotrexate (or) Anti-metabolite methotrexate, H2N N N

amethopterin and anti-neoplastic MTX, Rheumatrex, N NH

N O
and Trexall.
NH2 NH
OH
O

O OH

Inhibits tetrahydrofolate dehydrogenase essential for thy-

midylate synthesis.
3. Thalidomide   Contergan, Thalo-
O
mid, Immunoprin,
O
Talidex, Talizer, Neu- N
rosedyn, Distaval O NH
O
O
O
N

O NH

Used in the treatment of multiple myeloma and complica-

tion of leprosy.
4. Mechlorethamine Chlormethine Cl Cl
Alkalyting agent N
Nitrogen mustard
CH3

Chlorethazine
An alkylating agent that forms DNA adducts and cross-
Mustine links, to inhibit quickly proliferating cells.
5. Actinomycin D Antibiotic Dactinomycin,
cosmegan O
O N

NHH3C
O CH3
H O
N O
O
NH NH
O NH O
O O
CH3
H3C CH3
CH3 N
O O
N H O
N NH

O O
CH3
H2N
H3C CH3
O

Inhibits transcription. and averts elongation of RNA chain

Citation: Paulraj Mosae Selvakumar., et al. “An Insight into Cancer and Anticancer Drugs". Acta Scientific Medical Sciences 3.8 (2019): 32-43.
An Insight into Cancer and Anticancer Drugs

39

6. Cisplatin Platinum-based Cisplatinum, Cl

antineoplastic platamin, neoplatin, Cl
cismaplat Pt
2–

NH2
H2N

 Interferes with DNA replication, and destroying proliferat-

ing cells.
7. Vincristine Alkaloid Leurocristine, CH3

Vincasar, oncovin
N
HO
H3C HO O

H N
H
OH O CH3
N
H O OH
CH3
O
N
O
H O
CH3

Ceases the tubulin dimers from polymerizing, and causes

apoptosis.
8. Doxorubicin a n t h r a c y - Adriamycin, Caelyx, O

cline and antitumor Myocet OH

antibiotic 
HO
OH
O
OH
HO
H O
O NH2

O
OH
H

Intercalates and inhibits macromolecular biosynthesis caus-

ing DNA damage.

9. Mercaptopurine  Purine analogue Purinethol H

N N

N
N
H
S

Inhibits purine synthesis and metabolism by altering the

synthesis and function of nucleic acids.

Table 3: A list of well known commercially available anticancer drugs (Courtesy: PubChem)

an essential component of drug discovery these days [48a,b]. The and activity optimization via QSAR studies saves the cost of prod-
QSAR studies on antitumor drugs like nitrosoureas, aniline mus- uct development as predictions inturn could reduce the need for
tards, and aryl triazenes concluded that present drugs in clinical expensive animal tests, thus promoting a greener chemistry [51].
use are more hydrophilic than one might expect [49]. The activity Some of the atomic physiochemical properties such as Distance
transforming the effect of the structural features may serve to il- atomic physicochemical parameter energy relationships (DAP-
lustrate groundwork of novel anticancer drug hypothesis entrants, PER), can be better understood by novel structure-activity rela-
and also to provide a better understanding towards mechanisms of tionship such as 3D QSAR method using molecular descriptors, is
action of drugs [50]. The rational identification of new lead drugs validated on standard datasets [52].

Citation: Paulraj Mosae Selvakumar., et al. “An Insight into Cancer and Anticancer Drugs". Acta Scientific Medical Sciences 3.8 (2019): 32-43.
An Insight into Cancer and Anticancer Drugs

40

Other novel approaches towards cancer treatment switching off their ability to 'trigger' cell cycle initiation.
Cancer treatment has advanced rapidly over the last 70 years
starting from cytotoxic agents against cancer tumors. However, Immunotherapeutic approaches using immune cells or target-
significant systemic side effects towards targeted therapies which ing immune cells involved in cancer and inflammation offer novel
trigger cancer-cell cause apoptosis towards cancer cells but approaches to treat these changes. These cytokines also adapt re-
healthy tissues remain intact [53]. sponses of the immune cells involved in inflammation and tumor
surveillance [44].
Recent evidences state that electron transfer (ET), reactive ox-
ygen species (ROS) and oxidative stress (OS) plays an important There might be some group of people who might feel that natu-
role in the mechanism of many anticancer drugs [54]. It has been ral way of treating cancer is novel and successful nowadays. But
found that most chemotherapeutics increase intracellular levels it is not so. Alternative treatments such as acupuncture, yoga,
of reactive oxygen species (ROS), and alter the redox-homeostasis meditation may play important roles in cancer care. These tech-
of cancerous cells. This is due to the induction of oxidative stress niques may improve cancer-related fatigue, pain, mental health,
and ROS-mediated cell damage in cancer [55]. The regular ET and quality of life when they are added to standard cancer therapy
functionalities that square measure typically there within the drug [57]. Some doctors reject alternative medicine completely to avoid
metabolites square measure quinones (or precursors), metal com- unfortunate cases. A study taken on the month of august recorded
plexes (or complexors), hydroxylamine and nitroso from ArNO2 in the Journal of the National Cancer Institute looked at 281 cases
or ArNH2, and conjugated imines (or iminium species). These ET with non-metastatic breast, lung, colorectal, and prostate cancers
agents work catalytically in redox cycling with the development of who chose to be treated solely with an alternative approach, and
ROS from oxygen which is then confirmed by the use of electro- compared their survival with patients who received conventional
chemical data. The generated metabolites generally hold reduction cancer treatment. And the result stated that overall; those in the
potentials acquiescent to ET in vivo, thus giving rise to ROS. The alternative medicine group were 2.5 times more likely to die [58].
resulting OS destroys the cancer cell in reply. The action has been
termed phagomimetic based on correspondence to phagocytosis. The national cancer institute states that the overall cancer death
It is important to make out that drug action is mostly multipronged rate has declined to over 26% since the early 1990s [58]. Though
[54]. cancer has reduced multifold, there are still new cases appearing
with new symptoms of cancer. The study continues that the num-
Increasing repetition of class tumors and side-effects of thera- ber of new cancer cases per year is expected to rise to 23.6 million
py agents cut back the clinical effectiveness of an outsized kind of by 2030 [58] which clearly demonstrate the ardent need for the
antineoplastic agents that square measure presently getting used. development of novel anticancer agents with specific biomarkers
Thus, there is constant need to develop alternative or synergistic as molecular targets.
anticancer drugs with minimal side-effects. One such strategy to
develop effective anticancer agents is to research anticancer agents Market survey on anticancer drugs
derived from natural sources such as plants and their derivatives. A market survey taken Global anticancer drugs by transparency
Vinca alkaloid and their derivatives have been used extensively for market research states that anticancer drugs at a global level was
the treatment of various types of cancers. Polyphenols form one of valued at US$ 85.0 Bn in the year 2016 and is projected to expand
the most important and widely used classes of plant-derived ther- at a Compound Annual Growth Rate (CAGR) of about 6 to 7% from
apeutics for cancer prevention or chemotherapy because of their 2017 to 2025 to reach US$ 155.6 Bn in 2025 thereby offering a
antineoplastic properties [44]. scrupulous perceptive of anticancer drugs market across the globe
its key trends, drivers, restraints, and opportunities [65].
Thomas., et al, reported that the new class of drugs was the first
to target KAT6A and KAT6B proteins behave as a new weapon for Worldwide, the global anticancer drugs market is segmented in
fighting cancer that are known to play an important role in driv- to North America, Europe, Asia Pacific, Latin America and Middle
ing cancer [54]. Unlike chemotherapy and radiotherapy that work East and Africa of which North America region contributed the
by causing irreversible DNA damage, this new class of compounds most. The global anticancer drugs market of North America is
stops cancer progression by causing cell senescence thereby projected to expand at CAGR of over 6% and European antican-

Citation: Paulraj Mosae Selvakumar., et al. “An Insight into Cancer and Anticancer Drugs". Acta Scientific Medical Sciences 3.8 (2019): 32-43.
An Insight into Cancer and Anticancer Drugs

41

cer drugs market, to an estimated growth rate of 6.7% over fore- Conclusion
cast period from 2017 to 2025 respectively. Markets such as India, The causes for cancer progression are still a maze of unrevealed
China, and Brazil are still emerging and markets such as Japan and mysteries. The appropriate role of the immune system in both in-
Australia are well established [66]. flammation and cancer is not yet absolutely established. Further-
more, cytokines released by different cells in response to cancer
Targeted drugs hold over 40% of the global anticancer drugs and inflammation exerts surplus of effects on inflammation and
market. Minimum side effects as compared to cytotoxic drugs, the cancer prognosis. There is much advancement towards cancer
high specificity of the drugs, and effective results of these drugs treatment in the recent past. However, the causes of many cancers
is expected to drive the growth of the market sector through 2025 are not fully understood, making it difficult to develop effective
[67]. Some of the high-flying companies competing in the antican- treatments, reflected in the high failure rate of cancer drugs dur-
cer drugs markets include F. Hoffmann-La Roche Ltd, Eli Lilly and ing clinical development. Although modified and comprehensive-
Company, Celgene Corporation, Novartis AG, Pfizer Inc, Amgen Inc, release drug-delivery systems have been studied broadly, there
Bayer AG, AstraZeneca, Takeda Pharmaceutical Company Limited, remain gaps in the literature regarding their usage in cancer treat-
Merck and Co., Inc. etc. [66,67]. ment.

Literature survey on anticancer drugs Though there many advances in the treatment of most cancers
34609 documents are obtained from the Scopus search engine by current drug delivery systems, much work lies ahead in scruti-
for the keyword “Anticancer Drugs” from the year 1953 to 2019 of nizing the death rates owing to cancer. Therefore, with the under-
which 27,000 documents are of article type. When the subject area standings analysed from the recent researches on advancements of
is concerned, Biochemistry, Genetics, Molecular Biology and chem- anticancer drugs and remembering the traditional techniques as
istry are the most dealt division (Figure 5) with nearly 7409 docu- well, one can identify new targets and thus design novel anticancer
ments followed by medicine(6852 documents) and pharmacolo- drugs to bridge the gap of drawbacks that are discussed above.
gy(5502 documents). USA is the most contributing country as per
the results analysed in Scopus [68]. Further analyses state that the Bibliography
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Citation: Paulraj Mosae Selvakumar., et al. “An Insight into Cancer and Anticancer Drugs". Acta Scientific Medical Sciences 3.8 (2019): 32-43.
An Insight into Cancer and Anticancer Drugs

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Citation: Paulraj Mosae Selvakumar., et al. “An Insight into Cancer and Anticancer Drugs". Acta Scientific Medical Sciences 3.8 (2019): 32-43.